EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: joeqsmith on June 06, 2015, 12:54:30 am

Title: Handheld meter robustness testing
Post by: joeqsmith on June 06, 2015, 12:54:30 am
The latest spreadsheet is now available on GoogleDocs here:
https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit?usp=sharing (https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit?usp=sharing)

Answers to Frequently Asked Questions may be found here:

https://docs.google.com/document/d/1gEPFeOZpsNSm0-7sA98w2P5XE5x77Oal9dQEYvQnF6g/edit?usp=sharing (https://docs.google.com/document/d/1gEPFeOZpsNSm0-7sA98w2P5XE5x77Oal9dQEYvQnF6g/edit?usp=sharing)

Because the generator used for these tests changed from the first round to the second, it is difficult to correlate the data.  The UNI-T UT90A that was used in the first round had been repaired and tested again in the second round.   You will notice that while it survived a 3.2KV 2 ohms pulse in the first round, it fails at 1.5KV 2 ohm during the second round.   This is because the pulse width on the new generator was increased by a fair amount to more closely represent the IEC standard.   

You will also note that the AM530 did not make it as far into the tests at the AM510 did in the first round.  Some of the meters that 5KY provided me with were a much higher grade.   

Because the generator used in the first round of testing had to be rebuilt for each test ran, when the Fluke 87V was finally tested we only knew it was not as robust as the winner of the $50 shootout, the Fluke 101.    During the second round, enough people had asked me about the 87V that I went ahead and reran one and was amazed that it did so poorly.   


I have very few rules when it comes to leaving comments on my YT channel. 

1) Don't personally insult anyone.  Me or otherwise. 

2) Don't use my channel to post ads.  I don't run ads and don't ask for donations.  I am not making any money by posting this content.  For you to try and profit from my efforts is in very poor taste.           

3) Don't ask about how to modify a meter or how to construct a transient generator like I show.   Also, don't attempt to post lists of materials and don't try to tell others how to modify their meter.  If I ignored you, you should be fine.  If you are persistent most likely you will get banned.   There are many concerns when it comes to working with higher voltages and currents, even at the levels I show in the videos.       
 
I have YT filters setup.  If really don't care if your vocabulary is limited but the filters are fairly effective at picking up people who are intent on breaking the first rule.  Just be aware they are being used.   

If you want to post about my channel to others, please don't post false statements about the tests I am running.  Obviously I don't have any control over this.  I am just asking that if you don't understand the tests being ran, maybe just point them to the FAQs and call it good.   

If the above rules bother you and you feel you can't follow them,  please feel free to unsubscribe. 

Thanks.   

Table of Contents

First attempts at designing a waveform generator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg688021/#msg688021 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg688021/#msg688021)

Selecting the first set of $50 USD meters to run
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg688363/#msg688363 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg688363/#msg688363)

Initial testing of the waveform generator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg688607/#msg688607 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg688607/#msg688607)

The first set meters have arrived and round I of the testing begins
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg695530/#msg695530 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg695530/#msg695530)

Home made high voltage attenuator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg696093/#msg696093 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg696093/#msg696093)

Fuses are now banned from testing and the low energy levels are explaine
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg697304/#msg697304 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg697304/#msg697304)

From here on, its always a 2 ohm source....
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg697665/#msg697665 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg697665/#msg697665)

The UNI-T UT139C shows up late from China.
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg698362/#msg698362 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg698362/#msg698362)

Member Meter Junkie shows off their surge generator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg699353/#msg699353 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg699353/#msg699353)

First set of $50 meters, Semi Finals
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg699631/#msg699631 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg699631/#msg699631)

The UNI-T UT139C joins the remaining four meters and is damaged
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg699833/#msg699833 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg699833/#msg699833)

First set of $50 meters, Finals
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg701147/#msg701147 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg701147/#msg701147)

Member Meter Junkie runs a second Fluke 101 on their IEC combo generator at 12KV
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg703553/#msg703553 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg703553/#msg703553)

I push the Fluke 101 to 13KV 100us FWHH
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg704183/#msg704183 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg704183/#msg704183)

Hackaday runs a story on the testing
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg705738/#msg705738 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg705738/#msg705738)

The first of the higher cost meters, the Fluke 87V
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg708183/#msg708183 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg708183/#msg708183)

Member TechnologyCatalyst(5KY) steps into the game with a Round II of meters
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg746543/#msg746543 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg746543/#msg746543)

Designing a programmable transient generator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg748162/#msg748162 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg748162/#msg748162)

Testing the new transient generator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg763288/#msg763288 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg763288/#msg763288)

Testing the second set of meters, Round 1
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg769212/#msg769212 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg769212/#msg769212)

Testing the second set of meters, The Finals
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg777164/#msg777164 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg777164/#msg777164)

Statistics
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg779711/#msg779711 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg779711/#msg779711)

Rebuilding the generator (20KV, 50us FWHH), the Fluke 107 is pushed to its limit
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg780700/#msg780700 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg780700/#msg780700)

UNI-T UT90A plays music
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg782212/#msg782212 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg782212/#msg782212)

Designing the  half cycle AC line simulator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg789734/#msg789734 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg789734/#msg789734)

Initial testing of the Half cycle AC line simulator
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg795033/#msg795033 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg795033/#msg795033)

The Fluke 17B+ Review
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg811544/#msg811544 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg811544/#msg811544)

A second UNI-T UT139C is tested
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg815680/#msg815680 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg815680/#msg815680)

The Fluke 115 Review
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg818828/#msg818828 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg818828/#msg818828)

My old Mastech MS9508 / Cen-tech P37772
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg829927/#msg829927 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg829927/#msg829927)

Discussing input protection circuits
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg832724/#msg832724 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg832724/#msg832724)

The SONY Cyber-shot DSC-RX10M2 high speed Sony camera
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg841421/#msg841421 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg841421/#msg841421)

The UNI-T UT15C VoltStick
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg848706/#msg848706 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg848706/#msg848706)

The Keysight U1231A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg852693/#msg852693 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg852693/#msg852693)

First look at the current inputs
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg863105/#msg863105 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg863105/#msg863105)

The VICI VC99
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg881819/#msg881819 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg881819/#msg881819)

The HIOKI DT4252
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg890263/#msg890263 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg890263/#msg890263)

The UNI-T UT181A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg908123/#msg908123 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg908123/#msg908123)

Talking about ESD
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg911717/#msg911717 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg911717/#msg911717)

The UNI-T UT181A Repairs
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg915451/#msg915451 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg915451/#msg915451)

Low cost pocket meters
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg934733/#msg934733 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg934733/#msg934733)

Testing various DMM probes
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg945681/#msg945681 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg945681/#msg945681)

The TPI 194 II
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg967246/#msg967246 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg967246/#msg967246)

Temperature testing Part I
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg985119/#msg985119 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg985119/#msg985119)

Modifying the UNI-T UT61E (added robustness, backlight)
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1023221/#msg1023221 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1023221/#msg1023221)

YX-360 analog meter
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1025998/#msg1025998 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1025998/#msg1025998)

The Brymen BM235
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1030093/#msg1030093 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1030093/#msg1030093)

Pen Meters
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1054346/#msg1054346 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1054346/#msg1054346)

Modifying the UNI-T UT61E (Improving temperature drift)
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1074263/#msg1074263 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1074263/#msg1074263)

The CEM DT-9939 / Extech EX540
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1110590/#msg1110590 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1110590/#msg1110590)

Designing an ESD gun
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1126104/#msg1126104 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1126104/#msg1126104)

The Woods DMMW3 pocket meter
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1146838/#msg1146838 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1146838/#msg1146838)

The ANENG meters
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1149808/#msg1149808 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1149808/#msg1149808)

Testing various DMM high current shunts
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1159237/#msg1159237 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1159237/#msg1159237)

Modifying the UNI-T UT61E (20A measurements)
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1168820/#msg1168820 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1168820/#msg1168820)

Modifying the UNI-T UT61E (Low Burden Voltage)
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1182031/#msg1182031 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1182031/#msg1182031)

SIBA branded UXCELL Multimeter Fuse, Real or Counterfeit
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1196539/#msg1196539 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1196539/#msg1196539)

The Gossen Metrawatt Metrahit Ultra M248B
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1207306/#msg1207306 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1207306/#msg1207306)

The Gossen goes to the chamber along with some lower cost meters
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1209697/#msg1209697 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1209697/#msg1209697)

Dave sends a 121GW prototype
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1231731/#msg1231731 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1231731/#msg1231731)

Testing Dave's ASTM fuses
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1236035/#msg1236035 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1236035/#msg1236035)

Mr Joules
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1245107/#msg1245107 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1245107/#msg1245107)

My first Fluke 189, Finally a Fluke meter that I would actually use
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1258001/#msg1258001 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1258001/#msg1258001)

PlastX, restoring lens
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1262271/#msg1262271 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1262271/#msg1262271)

Dave runs a crude HV test
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1282305/#msg1282305 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1282305/#msg1282305)

The ANENG 8008
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1284726/#msg1284726 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1284726/#msg1284726)

Transient Testing Resistors
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1295646/#msg1295646 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1295646/#msg1295646)

ANENG, 14KV or Bust
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1299489/#msg1299489 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1299489/#msg1299489)

Selector Switch Life Cycle Testing Part I
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1313951/#msg1313951 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1313951/#msg1313951)

The ALL-SUN EM135 Automotive Meter
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1337607/#msg1337607 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1337607/#msg1337607)

Selector Switch Life Cycle Testing Part II
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1345200/#msg1345200 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1345200/#msg1345200)

Harbor Freight's CEN-TECH 95670, the rebranded E0SUN EM129 automotive meter
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1369480/#msg1369480 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1369480/#msg1369480)

Upgrades to my temperature chamber made from a meat packing box
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1371562/#msg1371562 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1371562/#msg1371562)

The Brymen BM319s Automotive Meter
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1382595/#msg1382595 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1382595/#msg1382595)

The Brymen BM869s 50,000 Cycle Switch Life Test
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1386207/#msg1386207 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1386207/#msg1386207)

Repeating the Brymen BM869s Transient Test
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1400700/#msg1400700 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1400700/#msg1400700)

The Brymen BM839 Professional Meter
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1405549/#msg1405549 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1405549/#msg1405549)

The Brymen BM869s, It's 14KV or Bust
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1407796/#msg1407796 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1407796/#msg1407796)

Repairing the homemade wideband high voltage probe
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1417243/#msg1417243 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1417243/#msg1417243)

The Fluke 87V, hot off the production line, full on testing
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1429536/#msg1429536 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1429536/#msg1429536)

The Fluke 87V, Extended High Voltage Testing
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1460870/#msg1460870 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1460870/#msg1460870)

The Fluke 87V, Another look at the old 87V and why it failed
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1467255/#msg1467255 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1467255/#msg1467255)

The Fluke T6-600, a responce to AvE
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1519018/#msg1519018 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1519018/#msg1519018)

Appling 1KV to various meter's, a responce to VoltLog
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1547579/#msg1547579 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1547579/#msg1547579)

Member Kean's Damaged 121GW, trying to determine the root cause
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1598113/#msg1598113 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1598113/#msg1598113)

Lighting strikes and damages some of my test equipment
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1646627/#msg1646627 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1646627/#msg1646627)

The MeterK MK01
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1684985/#msg1684985 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1684985/#msg1684985)

Transient Testing a Vintage Fluke 189
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1748807/#msg1748807 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1748807/#msg1748807)

The Brymen BM27s / Amprobe PM55A, is it really as bad as member True claims?
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1787117/#msg1787117 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1787117/#msg1787117)

Applying 1KVDC to various 4.7M resistors, preparing for a possible future test
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1787645/#msg1787645 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1787645/#msg1787645)

Viewer questions and comments
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1822403/#msg1822403 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1822403/#msg1822403)

The Brymen BM869s is directly exposed to several Watts of 7MHz CW
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1906376/#msg1906376 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1906376/#msg1906376)

The Brymen BM27s / Amprobe PM55A, Round I of testing
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1908218/#msg1908218 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1908218/#msg1908218)

Demonstrating using Labview to communicate w/ 121GW and UT181A over BlueTooth
Vaseline?  Yes, that's right.  Future Darwin Award
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1929244/#msg1929244 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1929244/#msg1929244)

The Owon B41T+ review
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2053840/#msg2053840 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2053840/#msg2053840)

Measuring battery life
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2081572/#msg2081572 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2081572/#msg2081572)

Rebuilding my first digital volt meter, the Fluke 8000A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2174864/#msg2174864 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2174864/#msg2174864)

The Yokogawa TY720 review
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2223951/#msg2223951 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2223951/#msg2223951)

Vibration Testing
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2299404/#msg2299404 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2299404/#msg2299404)

The Brymen BM27s pocket meter,  Round II  low battery, cold Winter months and vibration
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2344941/#msg2344941 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2344941/#msg2344941)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: N2IXK on June 06, 2015, 01:09:35 am
Any muiltimeter with a legitimate Cat III rating can handle Cat II circuits. 

The higher the Category rating, the higher energy the meter is safe with. You can always use a Cat III or Cat IV meter on lower rated circuits, but not the other way around....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 06, 2015, 01:14:38 am
After doing many searches on this site, I see a lot of posts about how meters are rated and tested.  There were even a few posts where people attempted to put some high voltage on them.   To be clear,  my plan is not to do an insulation test.   I am interested in surge.   My plan is to construct a small generator that I will use to weed out the worst meters.   If any meters are working after my basic test, I plan to further test them to the actual standards.   

CAT III 600 would require the surge use a 2 ohm source with a 6KV peak (3000 Amps peak).   This would ride on top of the AC.  Nasty stuff.  CAT II uses a 4KV peak with a 12 ohm source (333 Amps peak).   The test is the standard 8/20 waveform with a short applied or 1/50 with an open. 

A few good articles if you are interested:

http://www.grainger.com/content/safety-digital-multimeter (http://www.grainger.com/content/safety-digital-multimeter)
http://cp.literature.agilent.com/litweb/pdf/5990-4578EN.pdf (http://cp.literature.agilent.com/litweb/pdf/5990-4578EN.pdf)
http://faculty.riohondo.edu/jfrala/fluke_multimeters_-_abcs_of_multimeter_safety_multimeter_safety_and_you_application_note.pdf
 (http://faculty.riohondo.edu/jfrala/fluke_multimeters_-_abcs_of_multimeter_safety_multimeter_safety_and_you_application_note.pdf)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 06, 2015, 01:49:15 am
To start out, I need a generator that can create something close to the CAT II waveform.    You saw from my first post my quick generator.   This thing could hardly do much of anything.   

Over the last few days I built up several circuits, blew up every bench supply I have (an repaired them) and am close now to what I am looking for.   

My plan to do a sort of hybrid waveform.   I plan to limit the peak to 2KV but stay with the 2 ohm source.   I also plan to limit the duration of the pulse (not sub 1.0us like  my first throw together setup).   I plan to cut it in half.   For a CAT III meter this will be no problem what so ever as it is 1/3 the peak and half the duration with the same impedance.   

The second generator I cobbled up worked fairly well with a 12 ohm source but I wanted something that could do the above and put out that full 1000 Amps.   

The DOE Handbook Electrical Safety is available on-line.   I have played with KV low current equipment most of my life from TV and radios to modern test equipment.   So I am not concerned about this little project.    However,  I thought it would be interesting to highlight a few paragraphs from this document.

To create the waveform, I have been using a 500mA wall mount supply.   I use this to create a high voltage signal that is rectified and stored into a bank of capacitors.   

In Fig. 3-4. Complete electrical hazard classification system showing 5 major groups and 54 classes.  You can see capacitors are called out as Classes 3.x.   They are broken down by operating voltage.   

13.7.3.3 Safety Practices
An analysis of high-voltage circuits should be performed by a qualified person before work
begins unless all exposed energized parts are guarded as required for high-voltage work. The
analysis must include fault conditions where circuit current could rise above the nominal rated
value. Depending on the results of the analysis, any of the following may apply:

1. If the analysis concludes that the current is above 5 mA or stored high-voltage capacitive
energy is above 1 joule for voltages between 100 and 400 V DC, or above 0.25 joule for
voltages equal to or greater than 400 V, then the work is considered to be energized work
and should be performed in accordance with Chapter 2, "General Requirements" and/or
Chapter 3, "Hazard Analysis." See Chapter 3 for details on electrical hazard classification.
2. If the analysis concludes that the current is between 0.5 mA and 5 mA and between 0.25
and 1 joules, then the worker may be exposed to a secondary hazard (e.g., startle reaction)
that must be mitigated.
3. If the analysis concludes that the current is below 0.5 mA and below 0.25 joules, then the
worker exposure is minimal and no special precautions are required, even for high voltage
circuits.


From above, I plan to run the storage caps at 2KV.  Well above the 400V limit.  Looking at Fig. 3-9. Hazard Classes 3.x, capacitors, > 400 V, we can see that for 1-10 Joules, it is considered Class 3.3d.    This is a Red colored box.   

10) A red Class (X.3) indicates injury or death could occur by proximity or contact; often
the hazard is shock, contact burn, or arc-flash burn; engineering controls are
necessary for operation (e.g., listing or equipment approval), and administrative
controls are necessary for electrical work in this Class.


It should be obvious what the above means....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 06, 2015, 01:53:39 am
After making some calculations for the controller and output stages I ran a quick simulation of both.     Attached you can see the simulated response with a 1Meg and a 0.1 ohm load attached.   Not quite a 1000 Amps in the simulation. 

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 06, 2015, 03:38:02 am
Here is the final test generator.   No high voltage is exposed except at the banana connectors that plug into the target.  I was going to run it from batteries and still may.   There are two banana jacks on the side used to supply the power.   The key is plastic and is used to disable the unit.   The cable is silicone and the connectors are a CSCB series, both rated for much higher voltages than I plan to run. 

In the picture, you can see the damaged BK meter with the Pearson current transformer.  This is a 5000A 20MHz part, PN 410.   

Looking through Amazon, there is not a great way to search for CAT ratings.  Interesting is that all the work that was put into the DVM spreadsheet and all the concern for safety, I can't seem to find them rated by CAT an fuses.   I read through the forum about meters that don't meet their specs. 


Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Halvmand on June 06, 2015, 11:03:48 am
Interesting. Looking foward to se some test results.
Do you have any meters in mind for destruction?

I would personally like to see the fluke ripoff get exited.
http://www.ebay.com/itm/F14129-Aimometer-MS8215-Auto-Range-Digital-Multimeter-DMM-AC-DC-Voltmeter-Amme-/261831441592?pt=LH_DefaultDomain_0&hash=item3cf65ebcb8 (http://www.ebay.com/itm/F14129-Aimometer-MS8215-Auto-Range-Digital-Multimeter-DMM-AC-DC-Voltmeter-Amme-/261831441592?pt=LH_DefaultDomain_0&hash=item3cf65ebcb8)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Halvmand on June 06, 2015, 11:08:18 am
Oops. That is only CAT II rated.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Fungus on June 06, 2015, 12:50:35 pm
However,  after a quick search on the internet, it seems there are many low cost CAT III rated meters available.   I would like to know if any of these can handle CAT II.   
Anything that's CAT III is also CAT II.

Why am I only interested in testing them at CAT II?  Well that's about the only thing I would ever dare use any hand held meter for.   
The difference between CAT II and CAT III is very subtle in practice.

You can't tell if a mains socket is CAT II or CAT III just by looking at it. It's mostly to do with the distance from the circuit breakers (ie. the length/inductance of the wire between you and the distribution panel).

Well that's about the only thing I would ever dare use any hand held meter for.   
Me? I wouldn't use anything less than CAT III for regular mains work and I'd want a meter which I KNOW is CAT III, which in practice means Fluke. The numbers printed on the front of certain other brands of meter have been shown to be lies many times in these forums.

A Fluke 101 can be had for under $45, is easy to find, and comes with proper covered probes for mains AC work.

For that price I don't see any point in using anything else.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: G0HZU on June 06, 2015, 01:20:46 pm
Quote
Me? I wouldn't use anything less than CAT III for regular mains work and I'd want a meter which I KNOW is CAT III, which in practice means Fluke. The numbers printed on the front of other brands of meter have been shown to be lies many times in these forums.

A Fluke 101 can be had for under $45, is easy to find, and comes with proper covered probes for mains AC work.

For that price I don't see any point in using anything else.

The only thing I'd add to that is that for the vast majority of today's hobbyists, one should rarely need to directly measure the mains voltage with a meter anyway.

I avoid it as much as possible and use a sealed 'meter in a plug' if I'm curious about what the mains voltage is. Otherwise, I'd rather debug any mains wiring inside a piece of electronics gear with the unit switched off and unplugged from the mains and after a discharge.

To put this in perspective, I don't think I've measured the mains voltage directly with a DMM for many years. Obviously it would be different if I was an electrical engineer working on domestic or commercial power distribution etc but I'm quite happy to use basic DMMs (here and at work) for most low voltage electronics work. But I always keep them well away from mains voltage (230V AC here in the UK).

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 06, 2015, 03:47:20 pm
Interesting. Looking foward to se some test results.
Do you have any meters in mind for destruction?


Yes, I have started to make a list.   

Mastech MS8264, 8261, 8217 and 2008B.  The Extech MN15A.  The UNI-T UT90A.

I don't care if it had a bad review, was shown to have a glass fuse or appeared to have no protection at all.    I don't care what color it is, how many features it has or how many digits.     I am looking for anything under $50 with a CAT III 600V rating and fused current or clamp.   I am not affiliated with any company and have no bias towards any manufacture of hand held meters.  So any meter that meets the above, I would add to the list.   


A Fluke 101 can be had for under $45, is easy to find, and comes with proper covered probes for mains AC work.

I'll check.  I have another Fluke in mind and am not apposed to testing more of them if they meet the criteria.     


Currently I am working on a short video showing how the generator works and the waveforms it produces.    I was looking around the room for loads, and there was an LED bulb that would no longer turn on.    I connected the bulb to the generator and zapped it.   You know, that thing came back to life!  I kid you not!  I screwed it back into my fixture and it is still on.   Maybe a lead free solder joint failure.......
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Fungus on June 06, 2015, 04:23:46 pm
A Fluke 101 can be had for under $45, is easy to find, and comes with proper covered probes for mains AC work.
I'll check.  I have another Fluke in mind and am not apposed to testing more of them if they meet the criteria.     

Under $42.50 delivered to your door: http://www.ebay.com/sch/i.html?_nkw=fluke+101 (http://www.ebay.com/sch/i.html?_nkw=fluke+101)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 06, 2015, 05:44:16 pm
I closed my Ebay's account many years ago but I did find it on Amazon for under $50, ships direct from China with free shipping.  :-+

As I plan to buy one higher cost DVM, I started to look at the warranty and manuals.   Let's look at the 101 manual. 

Quote
LIMITED WARRANTY AND LIMITATION OF LIABILITY
This Fluke product will be free from defects in material and workmanship for one year from the date of purchase. This
warranty does not cover fuses, disposable batteries, or damage from accident, neglect, misuse, alteration, contamination, or
abnormal conditions of operation or handling.

Would a manufacture consider purposely testing their products, misuse or abnormal?   I guess we will find out.

For the first tests I plan to use my homemade surge generator to test all of the meters.   One thing that may not be clear is for my basic home surge tests, I am not going to inject on top of the input signal.   Surge would normally ride on the AC and would be tested +/- at 0, 90, 180 270.   It should be clear what this means as far as the peak voltages.    My concern is not so much the peak, but the energy available from the line after an arc.  When I made this video showing the effects of having the surge on top of a 24V DC source it's not hard to understand why. 

https://www.youtube.com/watch?feature=player_detailpage&v=ZeRkEKBYdzw#t=64 (https://www.youtube.com/watch?feature=player_detailpage&v=ZeRkEKBYdzw#t=64)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 07, 2015, 01:18:07 am
Here's the first of what will be several videos showing the my homemade scaled down surge generator in operation.   You can see the output waveform with various loads attached.   

https://www.youtube.com/watch?v=eVYGB9g00S8 (https://www.youtube.com/watch?v=eVYGB9g00S8)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Halvmand on June 07, 2015, 06:30:07 pm
Great video.

I think this one from amprobe could be a fun test:
Amprobe AM-510 for 44 $ on ebay
http://www.ebay.com/itm/Amprobe-AM-510-Commercial-Residential-Multimeter-with-Non-Contact-Voltage-New-/351412552068?pt=LH_DefaultDomain_0&hash=item51d1d20184 (http://www.ebay.com/itm/Amprobe-AM-510-Commercial-Residential-Multimeter-with-Non-Contact-Voltage-New-/351412552068?pt=LH_DefaultDomain_0&hash=item51d1d20184)

This too:
Amprobe AM-34 for 45 $
www.ebay.com/itm/Amprobe-AM-34-Cat-III-AUTO-Digital-Multimeter-/271867163408?pt=LH_DefaultDomain_0&hash=item3f4c8bb310 (http://www.ebay.com/itm/Amprobe-AM-34-Cat-III-AUTO-Digital-Multimeter-/271867163408?pt=LH_DefaultDomain_0&hash=item3f4c8bb310)

Or this one if it would drop just a tinsy bit in price and be available outside europe. From your video you don't sound european.
PeakTech 2015. It has really good features i think. Could not find a teardown of it, but some of the higher end models seems well build.
http://www.peaktech.de/productdetail/kategorie/multimeter/produkt/p-2015.html (http://www.peaktech.de/productdetail/kategorie/multimeter/produkt/p-2015.html)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: blackbird on June 07, 2015, 07:36:15 pm
I would like to see the Elix AL72D tested. It is a cheap multimeter sold by ALDI and some other discount supermarkets. They claim CATII and maybe it will survive the 750VAC or 1KVDC.

This model is also sold as the Range RE93A and I think under many other 'brands'.

The retailprice of this multimeter is somewhere between €10 and €15.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: MarkL on June 07, 2015, 09:18:38 pm
joeqsmith:

I'm interested in your surge generator.  Perhaps a schematic would be helpful.

How are you triggering the discharge of the capacitor bank?  Or are you just charging it until it arcs over in the DUT?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 07, 2015, 09:25:15 pm
Great video.

I think this one from amprobe could be a fun test:
Amprobe AM-510 for 44 $ on ebay

This too:
Amprobe AM-34 for 45 $

Or this one if it would drop just a tinsy bit in price and be available outside europe. From your video you don't sound european.
PeakTech 2015. It has really good features i think. Could not find a teardown of it, but some of the higher end models seems well build.

Thanks.  Glad you enjoyed the sparks.   

I like that 510.   I looked for the PeakTech but it does not appear available.   I assume there are many more that fall into this price/rating range.   


I would like to see the Elix AL72D tested. It is a cheap multimeter sold by ALDI and some other discount supermarkets. They claim CATII and maybe it will survive the 750VAC or 1KVDC.

This model is also sold as the Range RE93A and I think under many other 'brands'.

The retailprice of this multimeter is somewhere between €10 and €15.

I looked for this meter and could not find it.  However, I am really looking for CAT III 600 and up.   

I have now added some test lead points and a ground clip.   



Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 08, 2015, 02:46:36 am
You saw the sparks fly from my old BK that was CAT II rated.  Then you saw the sparks fly from my old Fluke. 

Against my better judgement, I decided to sacrifice one more meter to the surge god.   After seeing how bad the Fluke arced and blowing the control IC off the BK,  I thought it would be good to tape it.   The DM-301 appears as cheap as they come.   It has no CAT rating at all.  There are no CE or TUV marks.  There is no brand name on it but it was made in Korea.   I picked it up in a Sears outlet just to have a handheld.   It got used a lot and is in pretty rough shape now.     The LCD is cracked and I no longer use it so putting it on my scaled down surge generator is no problem.

In this video I talk a little about how I plan to go about evaluating the low cost meters.   I also talk a little about the 1010 standard and how I base my pass/fail criteria on it. 

When you start looking at 5 seconds between transients, 5 transients per mode, say 3 connectors testing all combinations, say 10 modes, and both positive and negative....  Well that's a very very long time to test each meter.   This can make for a VERY boring video.   If you ever had to test a product to these standards, you know what I mean.  It's a lot of waiting.   

As you watch this video, I stripped out most of the dead time waiting for the tests.   I also did not show every dial setting being tested.  I did leave some of it in order to show how slow this testing can go.   So if you get bored watching, just fast forward.     :blah: :blah: :blah:

If you are looking for a video where 1K resistors are measured and I talk about how big the fuses are, how soft the rubber case is or how the plastic feels or the colors of the plastic, these videos will not be for you.    But if you want to see some low cost meters getting hit with the surge, get some popcorn.   I plan to increase the energy to each and every one of them to destruction.   Only one meter will come out on top and I don't care which brand or where it was made.   

Once I have found the best of the low cost meters that I have purchased, then next question I need to answer is can a higher priced name brand meter go up against it.   :box: 

Without further adieu,  setting the bar low as it gets, here's the no brand name DM 301.  Enjoy
https://www.youtube.com/watch?v=pInd17ibzDg&feature=youtu.be (https://www.youtube.com/watch?v=pInd17ibzDg&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 09, 2015, 01:26:49 am
Tonight I increased the voltage from my homemade surge generator until the unbranded DM-301 failed.   This will be the starting point for testing the new meters.   If the new CAT III 600 rated meters I order can't out perform this super low cost unrated meter,  well, those would be some very poor meters.   The bar is set low.   


Short clip showing the breakdown.   
https://www.youtube.com/watch?v=USwqyjUD-jw&feature=youtu.be
 (https://www.youtube.com/watch?v=USwqyjUD-jw&feature=youtu.be)
   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: ivan747 on June 09, 2015, 02:47:24 am

May I suggest the Amprobe AM220? It has what would appear to be HRC fuses but are really normal fuses with a ceramic tube, no sand and potentially no vacuum.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 11, 2015, 01:27:32 am
I have narrowed my search for a higher end meter test against what ever low cost meter survives to the highest energy surge.   Keysight's U1272A, Fluke's 28II or the 87V.   All are in roughly the same price range.     Leaning towards the Keysight only because I have not had any failures with my HP meters and you saw what happened with my first Fluke.   

If anyone out there has actually ran surge tests on these and have an idea where they fail, it would be helpful.   I would rather have the more robust meter of the three for my testing.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: ivan747 on June 11, 2015, 03:30:25 am
Dave hates (feline) cats. If you rename the thread he might see it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Mark on June 11, 2015, 09:43:20 am
joeqsmith:

I'm interested in your surge generator.  Perhaps a schematic would be helpful.

How are you triggering the discharge of the capacitor bank?  Or are you just charging it until it arcs over in the DUT?

I am also interested in this as I am working on surge testing at the moment, it would be interesting to compare home made vs professional unit.  Can you post your schematic JoeQ? 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 11, 2015, 11:00:39 am
The BK 2703C, Mastech MS8264, Amprobe AM-510, Extech MN16A, Fluke 101 are now on order.   Does the Fluke 101 come out on top?   Do they all outperform my unbranded DM-301?     :popcorn:

I am also interested in this as I am working on surge testing at the moment, it would be interesting to compare home made vs professional unit.  Can you post your schematic JoeQ? 

While I mentioned it in Part 2, for any questions about surge generators refer to the IEC 61180-1.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 11, 2015, 08:57:55 pm
I had planned on narrowing my search of low cost meters down to eight total.   These are marked as ordered. 

Searching Google, I came across this article that may be of interest for those wanting to make their own test jigs.   I read it and it seems very good including a model for one.
http://www.denverpels.org/Downloads/Denver_PELS_20070918_Hesterman_Voltage_Surge_Immunity.pdf
 (http://www.denverpels.org/Downloads/Denver_PELS_20070918_Hesterman_Voltage_Surge_Immunity.pdf)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 14, 2015, 02:16:04 am
The Cen-Tech P98674 (re-branded Mastech MS8229).       

https://www.youtube.com/watch?v=zzQ57h2vGV0&feature=youtu.be (https://www.youtube.com/watch?v=zzQ57h2vGV0&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 14, 2015, 02:39:04 am
The Cen-Tech was not on schedule, right? It looks like a nice meter on paper. I'm gonna see how it performs on the tests.
I'm impressed by your commitment to test so many units financing this by yourself. You truly are a curious person.

My only suggestion is that you come up with a definitive test so we can compare the meters directly, before you do more damage.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 14, 2015, 05:55:26 am
The Cen-Tech was not on schedule, right? It looks like a nice meter on paper. I'm gonna see how it performs on the tests.
I'm impressed by your commitment to test so many units financing this by yourself. You truly are a curious person.

My only suggestion is that you come up with a definitive test so we can compare the meters directly, before you do more damage.

The internet is filled with a lot of chat about this subject.  Most seems more based on emotion than data.  So, yes, I want to know for myself if there is a low cost meter out there that can go head to head with a name brand.   

I had not planned on testing this meter.  It was sitting in the store and met the criteria so I thought I would try it out.   Seems like a popular meter.  I like it other than that it was damaged. 

For now I plan to stay with my very low energy tests.  These are the same waveforms I show in the first video.   To test these meters will take a fair amount of time and this is not something you want to do in a real lab.   What I would like to do is narrow it down to two meters.  My hope then is to test these meters to the full standards.   So if this is something people want to do, the standards are available and there are labs that will run these tests for you.     Right now, I'm not even close.   If any of them do make it into the 3KV range, I will be impressed. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 14, 2015, 06:36:04 pm
Looking at the MS8229, not sure what VR10 & 11 are for.  Was not able to locate a manual for it.   Aligned it to my HP (in current cal) for voltage.   Also adjusted the temperature and capacitance.   Fairly tight now.     Picture showing adjustments.  Also showing input resistance vs range.    More than enough room to tuck a few parts in there.  Notice the unused traces and THs.  Will switch the fuse out.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 16, 2015, 12:22:12 am
The BK made it in.   Still sitting in the box.   Looks like they have all shipped now so I may hold off and then test them together.   

Made a few changes to my test setup as well.  If it was not a weak enough test already, I plan to raise the source to 14 ohms.   This will make everything under CAT II 600.     It's a pretty sorry test I know but these meters are pretty sorry as well.    Also added a bias input to the box which should help me detect when a meter fails.   

For the good meter, I have narrowed it down to the Fluke 28 II or the Keysight U1272A.    It sounds like the 28 II may be more robust than the 87V. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 16, 2015, 02:30:22 am
You're telling me that the Mastech/Cen-tech meter only required recalibration?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 16, 2015, 02:31:26 am
It sounds like the 28 II may be more robust than the 87V.

I have heard it is.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on June 16, 2015, 07:06:12 am
If you would like me to test your favorite meter,  my criteria now is that they must be a hand held meter,  marked CAT III (600V) or higher, cost under $50 US and be fused.
I don't have any of these meters and they are not my favorites, but if you are still interested in the under $50, CAT III and fused criteria, here are some more using pricing from Amazon.com.

Greenlee DM-45
Uni-t UT61E - very popular recommendation by some eevblog people
Tekpower TP2844R

I can probably find more, but it will make a dent in your wallet if I continue.  You have already ordered 8 meters and probably spent over $300 already.

BTW, can you provide some internal pictures of the DM-301?  I would be interesting to see the inside construction of this.   Your video showing the pcb was too fast and I can't see anything too clearly.

Protek made a DM301 that looks like the one in your video.

http://www.hcqelectronic.com/en/a/Digital_Multimeter/20140919/71.html (http://www.hcqelectronic.com/en/a/Digital_Multimeter/20140919/71.html)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: Fungus on June 16, 2015, 07:42:57 am
Dave hates (feline) cats.
I vote we start sending him cat-related items in the mail.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: SeanB on June 16, 2015, 08:35:56 am
Dave hates (feline) cats.
I vote we start sending him cat-related items in the mail.

So who will send him something packed in a bag that used to contain kitty litter?

Nearly got a kitten yesterday, but the little bugger was too fast, and vanished into a sewer......
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 16, 2015, 08:48:52 am
Muttley's close, he could send Dave a cat, bugger the litter.  :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 16, 2015, 09:47:04 am
Muttley's close, he could send Dave a cat, bugger the litter.  :-DD
I'm sure Dave would come around if he actually had a kitten at home.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on June 16, 2015, 10:06:43 am
(https://s-media-cache-ak0.pinimg.com/736x/a6/f9/c3/a6f9c3952e469b02123a9fa8b124ddcc.jpg)

(http://suptg.thisisnotatrueending.com/archive/10150465/images/1275204902142.jpg)

(http://pictures.mastermarf.com/blog/2009/090502-kitten-sandwich.jpg)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on June 16, 2015, 04:11:56 pm
Perhaps a boook....

(http://ecx.images-amazon.com/images/I/51vLP99ua4L.jpg)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 16, 2015, 11:14:32 pm
If you would like me to test your favorite meter,  my criteria now is that they must be a hand held meter,  marked CAT III (600V) or higher, cost under $50 US and be fused.
I don't have any of these meters and they are not my favorites, but if you are still interested in the under $50, CAT III and fused criteria, here are some more using pricing from Amazon.com.

Greenlee DM-45
Uni-t UT61E - very popular recommendation by some eevblog people
Tekpower TP2844R

I can probably find more, but it will make a dent in your wallet if I continue.  You have already ordered 8 meters and probably spent over $300 already.

BTW, can you provide some internal pictures of the DM-301?  I would be interesting to see the inside construction of this.   Your video showing the pcb was too fast and I can't see anything too clearly.

Protek made a DM301 that looks like the one in your video.

http://www.hcqelectronic.com/en/a/Digital_Multimeter/20140919/71.html (http://www.hcqelectronic.com/en/a/Digital_Multimeter/20140919/71.html)

Dang where were you when I was looking for meters?!  I may go ahead and get that Greenlee DM-45.   

The Protek you link to appears the same from the outside.  The circuit board may be different now.   Picture showing PTC, zener and cut away areas.   Note the fuse has a few certifications.   

Plan to put some sort of matrix together for the testing.   Will attach it to the first post.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: amyk on June 17, 2015, 04:05:43 am
That looks like an 830. I'm not surprised it did so well, there's not much to go wrong in them and if something arcs over on the surge that'll just "relieve" the stress instead of popping the IC.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on June 17, 2015, 04:09:35 am
Dang where were you when I was looking for meters?!
The subject header with kitty, kitty, kitty did not attract my attention and I didn't notice the CAT III handheld surge tests due to the way my screen wraps.

Anyway, if you want more suggestions, I will look for more meters that fit your criteria.  If not, no worries.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on June 17, 2015, 04:21:29 am
Picture showing PTC, zener and cut away areas.
I think the green component that I circled in blue looks to be a varistor (MOV).  If I'm correct, it is this component that is helping the DM-301 survive your tests.

Lightages did some youtbue tests with an insulation meter (up to 5000V) that you might be interested in. See

https://www.youtube.com/watch?v=hhBbvIf3E0s (https://www.youtube.com/watch?v=hhBbvIf3E0s)

https://www.youtube.com/watch?v=8eDWb7qkx4A (https://www.youtube.com/watch?v=8eDWb7qkx4A)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 17, 2015, 04:31:47 am
Dang where were you when I was looking for meters?!
The subject header with kitty, kitty, kitty did not attract my attention and I didn't notice the CAT III handheld surge tests due to the way my screen wraps.

Anyway, if you want more suggestions, I will look for more meters that fit your criteria.  If not, no worries.

Maybe down the road.  I set a limit for myself what I was willing to spend on this little project.   I did not want any special handouts or frees as I did not want to be biased by any brand.    But, if you or anyone else finds any that claim a different cert like the Greenlee, I am interested. 

I attached a spreadsheet to the first post that outlines what tests I plan to run.   All of the meters will be functional tested, then tested against the CAT I.  If any pass, they will go on to CAT II and so on. 

Should be a fun week with lots of smoke.


That looks like an 830. I'm not surprised it did so well, there's not much to go wrong in them and if something arcs over on the surge that'll just "relieve" the stress instead of popping the IC.

I am impressed with it what ever it is.   Dirt cheap and has been very reliable.  It will be very funny if there is not a meter in the bunch that can hold up to at least the same levels!   :-DD :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 17, 2015, 04:41:33 am
I think the green component that I circled in blue looks to be a varistor (MOV).  If I'm correct, it is this component that is helping the DM-301 survive your tests.

Yes, that is probably what it is, a MOV. The problem with the MOV in the Digitek is that it is directly across the input jacks. This protects the meter very well but under a bad overload condition the MOV could blow up. It should be after the current limiting resistors and the PTC instead.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 17, 2015, 05:00:15 am
Picture showing PTC, zener and cut away areas.
I think the green component that I circled in blue looks to be a varistor (MOV).  If I'm correct, it is this component that is helping the DM-301 survive your tests.

Yes, I believe it is as well.  I had traced out some of the board and the opposite side is the input for the voltage and resistance.  There is a string of resistors that make of the attenuator for the different ranges.   These are next to the PTC and zener.       However, the current input also goes through another attenuator, these are the resistors located next to the MOV.    I suspect the MOV clamps anything from the current input only but I did not care enough to dig into it that deep. 

I had seen Dave's video with the hi-pot tester where he showed a switch arcing.  These sort of videos really don't tell me what I want to know or do anything for me.       

For example, say a meter had a MOV right across it's input with say a 600V clamp.  You set the hi-pot to 5 KV and no problems are found.  The hi-pot can't supply enough current to do any damage and the MOV just is happy to do it's job and clamp it.     If you did not know any better you may watch that and think, hey that meter looks pretty good.   Its taking  5KV.

I hit the same MOV with a 2KV surge and we find out is was not rated for that energy and BLAM.   I want to know if these meters can take the level of energy that they claim they can or not.   

I would have liked to have seen Dave surge test each meter he has reviewed to the point of failure and record this.    That to me is far more useful data than dropping it off a bridge to see the LCD crack.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 17, 2015, 10:59:01 pm
Let the games begin.    A few friends wanted in on the fun and donated their meters.  The one is actually CAT III 600.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 18, 2015, 04:40:22 am
You have been asked a couple of times if you will share the schematic of your pulse generator. Will you please?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Halvmand on June 18, 2015, 03:23:06 pm
So the fluke did not even meet cat-I, or are you saving the best for last?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 18, 2015, 03:54:24 pm
The Fluke might not have been one of the five tested.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dom0 on June 18, 2015, 03:57:31 pm
The Fluke might not have been one of the five tested.

(https://imgs.xkcd.com/comics/frequentists_vs_bayesians.png)

:)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 18, 2015, 03:59:00 pm
There'll be a massive storm if the Fluke fails.

 :popcorn:

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 18, 2015, 10:02:50 pm
I have been testing meters all day.   For the lower than CAT I tests, six out of the ten passed. 

I have been running the 2KV 14ohm 2/10 on the six and so far everything is good.  I may just move to the 2 ohm, 2KV then to the 2 ohm 4K.   Try and thin the heard a little.   I plan to run the DM-301 on this test.     If anything lives through this, it will be time to make another transient generator that packs a bigger punch. 

I did manage to edit the video for my attenuator.   
https://www.youtube.com/watch?v=bj_YndfA4Qs&feature=youtu.be
 (https://www.youtube.com/watch?v=bj_YndfA4Qs&feature=youtu.be)    I'll demo this thing once the energy levels get up a little higher. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 04:40:18 pm
The generator is back up and putting out some nice pulses.    Time to unload the camera and get caught up.   

Starting off the CAT I tests, the Cen-Tech 98025 from Harbor Freight... 
https://www.youtube.com/watch?v=VnjKfzZeZlo (https://www.youtube.com/watch?v=VnjKfzZeZlo)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dom0 on June 19, 2015, 04:54:01 pm
https://www.youtube.com/watch?v=dLfhQn9LwyA&feature=youtu.be (https://www.youtube.com/watch?v=dLfhQn9LwyA&feature=youtu.be)

YouTube says this video may contain music and I can't watch it(*).

(*) Private entity 'GEMA' owns 99.99 % of music rights in DE but has a clinch with Google and doesn't license the rights to them.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 06:55:06 pm
Yep, the radio was on in the background and it picked up a few seconds of music as a copyright issue.    :--
I'll be more careful in the future.

Here's the Gardner Bender GDT-311
https://www.youtube.com/watch?v=l8SMr_OVBho&feature=youtu.be (https://www.youtube.com/watch?v=l8SMr_OVBho&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on June 19, 2015, 07:43:50 pm
Thanks for putting these together.  I think this thread is the first were anyone has shown DMM's subject to approximations of IEC surge waveforms.  A question is at just that amount of energy, do they die gracefully or survive?  Survive would be a plus, money wise.

Are any of the test meters safety rated by external NRTL labs?   The B&K that failed?

In Dave's early videos, the energies are far above their CAT ratings, but its most useful because it shows how the meters respond in a severe failure.

https://www.youtube.com/watch?v=M-FZP1U2dkM (https://www.youtube.com/watch?v=M-FZP1U2dkM) 

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 08:38:03 pm
Thanks for putting these together.  I think this thread is the first were anyone has shown DMM's subject to approximations of IEC surge waveforms.

No problem.   I am just as much interested myself in seeing how they stackup.   

A question is at just that amount of energy, do they die gracefully or survive?  Survive would be a plus, money wise.

Are any of the test meters safety rated by external NRTL labs?   The B&K that failed?

The old BK 2706A has no markings on it.


DM-301 is UL listed   
AMPROBE AM-510, CE CSA (Canadian and USA)
BK 3703C, CE
Gardner Bender GDT-311 shows it as Intertek Listed, UL 61010-1, CAN/CSA-C22.2
Klein MM500 is UL listed
FLuke 101, I can't read Chinese but there is no obvious mark on the box
EXTECH MN16A, ETL, CE
UNI-T UT90A,  I can't read Chinese but there is no obvious mark on the box


In Dave's early videos, the energies are far above their CAT ratings, but its most useful because it shows how the meters respond in a severe failure.

I am hitting them with far less energy than the IEC standards call for.    When I tested my old Fluke, that was the most violent failure so far.    But we are just getting started.....  :-DD   

Again the real energy would come from the mains and I am not using anything like this in my testing.    So even if a meter were to pass all of my tests,  it should be obvious that this does not
mean it would pass the real IEC standards.   
   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 08:54:41 pm
Halvmand's  AMPROBE AM-510
https://www.youtube.com/watch?v=Hcv6ADmf4Q8&feature=youtu.be (https://www.youtube.com/watch?v=Hcv6ADmf4Q8&feature=youtu.be)

This meter was later fully tested.  Gets the big  :-+

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 10:04:33 pm
The Mastech MS8261

https://www.youtube.com/watch?v=A-_76sAeSyM&feature=youtu.be (https://www.youtube.com/watch?v=A-_76sAeSyM&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 10:36:24 pm
The BK 2703C

https://www.youtube.com/watch?v=qeywr8VUNdY&feature=youtu.be (https://www.youtube.com/watch?v=qeywr8VUNdY&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 19, 2015, 11:28:16 pm
The UNI-T UT-90A

https://www.youtube.com/watch?v=ijFQJGlVAt8&feature=youtu.be
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: IanB on June 19, 2015, 11:49:25 pm
I am hitting them with far less energy than the IEC standards call for.    When I tested my old Fluke, that was the most violent failure so far.    But we are just getting started.....  :-DD   

Again the real energy would come from the mains and I am not using anything like this in my testing.    So even if a meter were to pass all of my tests,  it should be obvious that this does not
mean it would pass the real IEC standards.   


Correct me if I'm wrong, but meters are expendable and people are not. So believe the IEC tests are intended to ensure that any damage stays inside the meter and does not cause injury to a person holding it. For a meter itself to survive unharmed seems like a very strong requirement.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 12:20:35 am
Correct me if I'm wrong, but meters are expendable and people are not. So believe the IEC tests are intended to ensure that any damage stays inside the meter and does not cause injury to a person holding it. For a meter itself to survive unharmed seems like a very strong requirement.

I would suggest anyone interested in the subject to start by reading the IEC standards.   I read parts of one during one of the early videos.  There was also a fairly lengthy discussion on this forum a few years back.   If you see a problem with what I am doing, feel free to comment. 

I am involved in testing to the IEC standards from time to time and will say that surge is one of my favorite tests to run.   


Here's the EXTECH MN16A
https://www.youtube.com/watch?v=vhJmjSCcfzQ&feature=youtu.be (https://www.youtube.com/watch?v=vhJmjSCcfzQ&feature=youtu.be)


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 20, 2015, 02:09:38 am
I have been a long time lurker, and reader, of these forums.  I have not found the need to post until this thread.

I actually have done some IEC 61010 surge testing on meters, and I think you have done a great job building your own tester. I also like seeing how many of these low cost meters survive these surges. However, to meet the CAT ratings in 61010, they do not HAVE TO pass these surges.

My understanding of IEC 61010 is that the meter must not become a hazard when they take this surge. That means not flames or explosions when you hit the meter with the surge. Or, no broken cases or flying parts. But, the meter does not have to function after the surge to get the rating.  So, a meter that arcs over a trace or dial pad, but does not blow apart, would be considered a pass.

It is nice to know that some of these low end meters still function after your surges. But, they are not required to.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 20, 2015, 03:17:39 am
Halvmand's  AMPROBE AM-510
https://www.youtube.com/watch?v=Hcv6ADmf4Q8&feature=youtu.be (https://www.youtube.com/watch?v=Hcv6ADmf4Q8&feature=youtu.be)

This meter was later fully tested.  Gets the big  :-+

Nice to hear.
-The owner of an AM550 (or was it 560?)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 04:13:41 am
I have been a long time lurker, and reader, of these forums.  I have not found the need to post until this thread.

I actually have done some IEC 61010 surge testing on meters, and I think you have done a great job building your own tester. I also like seeing how many of these low cost meters survive these surges. However, to meet the CAT ratings in 61010, they do not HAVE TO pass these surges.

My understanding of IEC 61010 is that the meter must not become a hazard when they take this surge. That means not flames or explosions when you hit the meter with the surge. Or, no broken cases or flying parts. But, the meter does not have to function after the surge to get the rating.  So, a meter that arcs over a trace or dial pad, but does not blow apart, would be considered a pass.

It is nice to know that some of these low end meters still function after your surges. But, they are not required to.

Glad you felt inspired to post the first time.   I have never tested a multimeter for surge and while I have read the standards, I may have missed more than one or two things....

I am very interested in understand how people in the know interpret these standards.  So, let's start with what part are you referring to?   I have all the latest docs, so no problem to follow along. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 20, 2015, 04:30:20 am
How can we find a copy of  the IEC 61010-1 3rd edition?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on June 20, 2015, 07:58:39 am
Quick check and this pops up.

https://www.isa.org/pdfs/microsites121/s-820201/ (https://www.isa.org/pdfs/microsites121/s-820201/)

Quote
All text of IEC 61010-1:2001 is included. National Deviations are shown by strikeout through text
deleted and underline under text added. Tables, or portions of tables, that are to be deleted are
shown as shaded; figures to be deleted are marked with the overlay "X." There are eleven
annexes in this standard. Annexes G, H, DVA, DVB, and DVC are informative and are not
considered part of this Standard. The remaining Annexes are normative and are considered part
of this standard.

Have fun reading this 156 page doc, though it is not the latest revision, but should be close. If you want the full version it will cost you 340 Swiss Francs ($370 US currently) for either the english/french or the Spanish versions.


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: amyk on June 20, 2015, 12:47:01 pm
How can we find a copy of  the IEC 61010-1 3rd edition?
With Google. (http://www.google.com/search?q=IEC+61010-1%3A2010+pdf)

You can thank the Chinese for that... ;)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 01:39:39 pm
The Klein Tools MM500

https://www.youtube.com/watch?v=Bt3QG4pyqvw (https://www.youtube.com/watch?v=Bt3QG4pyqvw)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 20, 2015, 01:40:27 pm
I have all the documents at work, so I would not be able to post that section until Monday.  I can't post the whole document, since that is not allowed.

In 61010-1 3rd Edition, the over voltage and surge tests have been removed. They are now covered in 61010-2-033 for DMM's and 61010-2-032 for clamp meters.  Basically, a large surge event like 6kV or 8kV is a lightning type event, and would rarely happen. This is why the meter does not have to survive, but does still need to protect the user. The standard even states that you do not need any transient protection devices in the unit. However, "IF" you choose to install these protection devices, then they must be able to withstand 5 pulses in each polarity without being damaged. But, they are not required to be there, if the meter can take the surge without becoming a hazard.

A requirement that got tougher to meet in this latest standard is over voltage on any dial position. Past standards allowed you to state what level of protection you had designed in. For example, if you had a DMM that measured to 600V, you could say the the resistance input is only protected to 250V, and this was sufficient to pass the standard. Now, it states that the meter can not become a hazard if you have the full rated voltage on any switch position, and any jack combination. Again, the meter does not have to survive this, just not become a hazard. You can find a bunch of videos where the meter catches fire with 600V applied to the resistance input. That fails the IEC specs now. But, if it had failed gracefully, it would have passed.  Of course, the better designed units can survive that over voltage, and still function.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 20, 2015, 02:00:01 pm
The Klein Tools MM500


In your video, you said you believed that Klein unit could survive higher than a 10 foot drop.  A quick google search returned this.

http://youtu.be/7XL0JtSc-60 (http://youtu.be/7XL0JtSc-60)

Dave also took that meter on his mud run, and it survived that.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 02:11:57 pm
And last but not least, the Fluke 101

https://www.youtube.com/watch?v=ScILWjPJzSE (https://www.youtube.com/watch?v=ScILWjPJzSE)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on June 20, 2015, 02:20:39 pm
This was all discussed at length in a previous thread. https://www.eevblog.com/forum/projects/cat-ratings-and-interpretation/msg159305/#msg159305 (https://www.eevblog.com/forum/projects/cat-ratings-and-interpretation/msg159305/#msg159305)
In a multimeter, the only high voltage transient protection possible, if fitted, are MOVs or GDTs (gas discharge tube).
Good meters also have crowbar circuits to protect other ranges ( Ohms, caps, etc...) up to 1000V (with diodes or transistors). Cheaper ones, as per their user manuals, can often only cope with 250V max. (As mentioned by Meter Junkie, this protection must now match the max voltage CAT rating)
Another new requirement concerns fuse ratings. They must now be HRC fuses and must also match the max voltage CAT rating.

The test on the current ranges has also been modified and now consists of applying twice the max voltage CAT rating (2000V max), with a ruptured fuse in place, for 1 minute.
The high voltage transient tests remain the same.
There must not be any possibility of electrical shock, fire, sparking and explosion, during and after the test. Multimeters are not expected to function properly after the series of tests.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 02:23:42 pm
In 61010-1 3rd Edition, the over voltage and surge tests have been removed. They are now covered in 61010-2-033 for DMM's and 61010-2-032 for clamp meters.

...

Of course, the better designed units can survive that over voltage, and still function.

61010-2-033 is what I quoted. 

The goal is the same no matter.  One meter will be more robust than the others. 


The Klein Tools MM500


In your video, you said you believed that Klein unit could survive higher than a 10 foot drop.  A quick google search returned this.

Dave also took that meter on his mud run, and it survived that.

I like the video!!  I had never heard of the brand until now. 

If I needed to have a very limited meter on a mud run to do some 1K resistor measurements, this would be it.    :-+   It's so light weight and solid, after these tests I may try and see what it takes to damage it.  Maybe drop it out of a plane or shoot it out of a cannon...  :-DD

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on June 20, 2015, 06:16:14 pm
In 61010-1 3rd Edition, the over voltage and surge tests have been removed. They are now covered in 61010-2-033 for DMM's and 61010-2-032 for clamp meters.

...

Of course, the better designed units can survive that over voltage, and still function.

61010-2-033 is what I quoted. 

The goal is the same no matter.  One meter will be more robust than the others. 


The Klein Tools MM500


In your video, you said you believed that Klein unit could survive higher than a 10 foot drop.  A quick google search returned this.

Dave also took that meter on his mud run, and it survived that.

I like the video!!  I had never heard of the brand until now. 

If I needed to have a very limited meter on a mud run to do some 1K resistor measurements, this would be it.    :-+   It's so light weight and solid, after these tests I may try and see what it takes to damage it.  Maybe drop it out of a plane or shoot it out of a cannon...  :-DD

Klein is an american company that tends to focus on tools for electricians and telecommunications. I wonder who is manufacturing this meter for them. I am sure some others know of a few Korean multimeter companies. I can't think of any off the top of my head.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on June 20, 2015, 08:10:57 pm
Klein is an american company that tends to focus on tools for electricians and telecommunications. I wonder who is manufacturing this meter for them. I am sure some others know of a few Korean multimeter companies. I can't think of any off the top of my head.
Fine Instruments makes some of Klein's multimeters.  See

http://www.finest.co.kr/ci.html (http://www.finest.co.kr/ci.html)

Klein, however, has at least two multimeters that are "Made in the USA", but not for $50.

http://www.kleintools.com/catalog/multimeters/electricians-trms-multimeter (http://www.kleintools.com/catalog/multimeters/electricians-trms-multimeter)

http://www.kleintools.com/catalog/multimeters/electricians-hvac-trms-multimeter (http://www.kleintools.com/catalog/multimeters/electricians-hvac-trms-multimeter)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 20, 2015, 08:15:32 pm
It also looks like Klein gets a couple of their models from Mastech, at least from the appearance.
http://www.kleintools.com/catalog/multimeters/auto-ranging-multimeter (http://www.kleintools.com/catalog/multimeters/auto-ranging-multimeter)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 20, 2015, 08:39:15 pm
It's so light weight and solid, after these tests I may try and see what it takes to damage it.  Maybe drop it out of a plane or shoot it out of a cannon...  :-DD
Joe. Your disrepect of perfectly good test equipment worries me.
Some might say you are a sick puppy.  ;)

Great thread, watched it all the way.  :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 10:28:54 pm
It's so light weight and solid, after these tests I may try and see what it takes to damage it.  Maybe drop it out of a plane or shoot it out of a cannon...  :-DD
Joe. Your disrepect of perfectly good test equipment worries me.
Some might say you are a sick puppy.  ;)

Great thread, watched it all the way.  :popcorn:

 :-DD 

I'm glad you are enjoying it.   

Today was a good day.  The unbranded DM-301 has finally been beat!  Not to mention, it was put to rest.  I am sorry to say that I did not catch it on video.  I forget to press record.   |O 

For those who are concerned about how the meters are holding up.  Here's the final six meter getting hit with a 2KV transient with a 14 ohm source. 

https://www.youtube.com/watch?v=1-lRvF8Nen0 (https://www.youtube.com/watch?v=1-lRvF8Nen0)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 20, 2015, 11:31:16 pm
A few updates.   I began testing the meters today with enough energy to take out the low current fuses.   Rather than replace expensive fuses, I am no longer testing the current inputs.    However, all of the other modes are still being tested.   If you may recall, early on I talked about removing the fuses during the testing.   As it turned out, this was not a problem until today.   

I am very sorry to say that 2 of the six meters are no longer with us.   :'( :'(     The four remaining do not have an easy life ahead of them.    If your favorite company was knocked out of the running, it's not because it was treated unfairly.   For those who are concerned about meters not functioning during the test, these four surviving brands have shown they produce a more robust product.  You may argue that they do not need to but I can tell you, I personally would rather have a meter that does.   

On the generator side of things, I have been clear all along that I am not testing to the IEC standards.   This is a one off generator just to weed things out.   The energy has always been lower than the standard calls for.    I am nearing the end of what I can do with this one.   It was already at lethal levels but these last four I have a feeling are going to require more than I can put out.   But don't worry.  I have plans to build a slightly larger and more lethal version.....   So stay tuned!

If you want a preview of today's testing, enjoy the following short clip:
https://www.youtube.com/watch?v=16e0KvkWIi4 (https://www.youtube.com/watch?v=16e0KvkWIi4)

 








Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 21, 2015, 12:46:52 pm
So, which 2 of the 6 that passed the 2kV testing died?  Will you be hitting the remaining 4 with 3.5kV today?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 21, 2015, 01:31:12 pm
So, which 2 of the 6 that passed the 2kV testing died?  Will you be hitting the remaining 4 with 3.5kV today?

Just a warning, the results may not be what you're expecting.  I'll have the video up soon.   It will all be in one long video.  Nothing was cut, except for the functional testing at the end.   

Well, we can't make an omelet without breaking a few eggs.   Last night I added about 30% or so more capacity and higher voltage.   The test is set to go.     :-+ 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 21, 2015, 02:59:58 pm
Well, I'm not really hoping for a certain winner, so I don't know what you think I'm expecting. But, based solely on the strength of the brands, I would guess the Extech and Uni-T would be the 2 that didn't make your last test. I expect the Fluke to go the distance.

I am looking forward to see the rest of your testing.  I do surge testing on telecom equipment, but don't test meters for my job. I love blowing stuff up with that machine.  The lab I work in does have a surge generator that can do 12kV through 2 ohms for IEC testing.  My telecom testing does not require me to go that high, so I don't use that machine. But, I'm not going to spend money buying meters just to see how they hold up on that machine.  I guess I'm just not as curious as you. But, I am curious enough to follow this thread, and see which brand holds up the best.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on June 21, 2015, 03:13:25 pm
Joe,  continued good job  :-+,  I watch videos with as much anticipation as Game of Thrones  ;D.  I am away for awhile so can't post for sometime.  Keep up the good work.   :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 21, 2015, 03:41:11 pm
Well, I'm not really hoping for a certain winner, so I don't know what you think I'm expecting. But, based solely on the strength of the brands, I would guess the Extech and Uni-T would be the 2 that didn't make your last test. I expect the Fluke to go the distance.

I am looking forward to see the rest of your testing.  I do surge testing on telecom equipment, but don't test meters for my job. I love blowing stuff up with that machine.  The lab I work in does have a surge generator that can do 12kV through 2 ohms for IEC testing.  My telecom testing does not require me to go that high, so I don't use that machine. But, I'm not going to spend money buying meters just to see how they hold up on that machine.  I guess I'm just not as curious as you. But, I am curious enough to follow this thread, and see which brand holds up the best.

Quote
Just a warning, the results may not be what you're expecting.
   

It was more a general statement to the 20 or so people watching the videos.   I think we all have our favorites.  I have been fairly vocal about the Klein Tools meter being the last survivor.   But to be clear, they all get the same abuse.   I am not being paid to run these tests,  no distributors have provided me with free meters nor do I work and have never excepted any payment from any manufactures.   With all the hype, I just wanted to know myself how a small sample would hold up.

I watched several reviews on handheld meters before I started looking to run this little experiment.  Based on what I saw with the UNI-T brand,  I would have thought it would have failed during the first test.   

Really, you specifically should run these tests!   If you can do the 8/20 2 ohm, you are all set.   Think your work would let you rent the lab for 4 days free of charge?   :-DD


Joe,  continued good job  :-+,  I watch videos with as much anticipation as Game of Thrones  ;D.  I am away for awhile so can't post for sometime.  Keep up the good work.   :popcorn:

Thanks.   

If you want to know which ones live and and die, enjoy the following:
https://www.youtube.com/watch?v=x9oBQVn9LlA (https://www.youtube.com/watch?v=x9oBQVn9LlA)







Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on June 21, 2015, 05:07:45 pm
Got a sledge hammer and a large rock to make sure the failures are properly worked over? Failing that a train line, some duct tape and a passing goods train ( plus a high speed camera to catch the squish) works well. A coin on a train line becomes pretty flat afterwards, provided you can actually find it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 21, 2015, 05:20:47 pm
Wow, I am really surprised that the B&K died before the Uni-T.  I look forward to your next pulse machine.

There still seems to be some confusion about whether a meter should survive or just not harm the user. I compiled quotes from different posts in an old thread on CAT ratings. They were excerpts from different parts of the IEC standards but I don't know where this one is from specifically because the IEC documents are not freely available, or at least I have not found them yet. It would be really nice if the IEC would make their publications freely available instead of making people pay for them. It would seem to me to be in the public's best interest to have the information. Hopefully someone with the full standards can clarify this. The part I have states:

Quote
101.4  Functional  integrity
After the voltage of  4.4.2.101  has  been applied to the  METER, the  METER  shall continue to be
able to indicate the presence of HAZARDOUS  LIVE  voltages up to the maximum RATED  voltage.

If this is relevant, then any meter you have failed before this video that also has a CATII rating or higher can't be sold in the EU legally. The ones that failed this video with a CATIII rating also cannot. It is my understanding, from watching a video by Martin Lorton at the Fluke facilities, that the US has no restrictions on the legal sale of multimeters, not yet.

There is another part that specifies that any meter should not fail in a way that could harm the user. I wonder how that is actually tested without putting a person in harm's way?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 21, 2015, 06:33:26 pm
Today's tests went well.   However, I'm sorry to say, I am done for a while.   It has been a solid, three day frenzy with a lack of sleep, food and exorcise.  I managed to run the last set of tests but I am no longer thinking clear and have started to make some mistakes.

What you don't see in these videos is how often I have had the generator apart to rebuild for the next test.   While there is always some risk, this is not something I want to play with when I'm tired.   

Things are only going to continue to get worse for the remaining meters as the source impedance stays fixed at 2 ohms, the time is pushed out to 50uS and the peaks are nearing 4KV.   The attached waveform shows how far things have progressed.   The generator is set for the next tests...  Who will survive???
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 21, 2015, 06:40:03 pm
In your video, you said you believed that Klein unit could survive higher than a 10 foot drop.  A quick google search returned this.
Those $4 Chinese meters can survive that...

Here's me dropping one:

https://www.youtube.com/watch?v=DWBSBJ16zWg (https://www.youtube.com/watch?v=DWBSBJ16zWg)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 21, 2015, 07:58:40 pm


Really, you specifically should run these tests!   If you can do the 8/20 2 ohm, you are all set.   Think your work would let you rent the lab for 4 days free of charge?   :-DD


There wouldn't be a need to "rent it".  I can have access to it whenever I want.  My point was that I was not going to spend my money ordering out meters to blow up for the fun of it.  I would have fun doing it, but I have other uses for my money.

However, I really appreciate that dedicated people like you have no issue spending money for that kind of fun.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 21, 2015, 08:04:43 pm

I have a picture of the beast the day it arrived, but I don't know how to post it on here. It is pretty massive.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 21, 2015, 08:48:01 pm

I have a picture of the beast the day it arrived, but I don't know how to post it on here.
At the bottom of the page when posting there is a plus sign for attachments, click this and follow your nose.  ;)
Note the restrictions of type and size of files.
I suggest you compress the pics, usually 100K will give plenty of detail.

If you Quote somebodies post, you will see the various formats used to display pics.
Some host pics, others use EEVblog and upload.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on June 21, 2015, 10:46:31 pm

I have a picture of the beast the day it arrived, but I don't know how to post it on here.
At the bottom of the page when posting there is a plus sign for attachments, click this and follow your nose.  ;)
Note the restrictions of type and size of files.
I suggest you compress the pics, usually 100K will give plenty of detail.

If you Quote somebodies post, you will see the various formats used to display pics.
Some host pics, others use EEVblog and upload.

 I use IMGUR a lot, with an account on IMGUR. Haven't had ANY images deleted and seems to be pretty stable. In fact, looking back over a few older posts from a few years ago. I still used IMGUR without an account and those images have not been deleted either.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 22, 2015, 01:23:08 am
Cool, looks like a nasty bit of gear.  :o

Tip
Place a "Insert image" link in your post, then post, copy the original image's link URL, then edit post placing the URL between the "Insert Image" brackets.

Like this:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=157646)

Now if you quote this post you can see the syntax used.  ;)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 22, 2015, 02:01:22 am
Maybe I'll stop by Harbor Freight tomorrow, and pick up a $5 meter, and see what this machine will do to that.  I don't mind blowing up a $5 meter.  I just can't justify several $50 meters like Joe.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 22, 2015, 03:17:17 am


Really, you specifically should run these tests!   If you can do the 8/20 2 ohm, you are all set.   Think your work would let you rent the lab for 4 days free of charge?   :-DD


There wouldn't be a need to "rent it".  I can have access to it whenever I want.  My point was that I was not going to spend my money ordering out meters to blow up for the fun of it.  I would have fun doing it, but I have other uses for my money.

However, I really appreciate that dedicated people like you have no issue spending money for that kind of fun.

That's very nice of them to allow employees access to such equipment for their own use!  Do you have to be trained and have a second person around or can you just run it?   

No problem.  Maybe a few of us can learn something from it, plus have a little fun at the same time.

I've attached a picture of the surge generator.  It is 27 inches high, and 24 deep, and about 17 wide.  The thing weighs over 100 pounds, and can deliver the full 6000 Amps at 12 kV.  If I remember right, it set the lab back about $34,000.

 :-DD  Notice the slight difference in size!   :-DD    I was not able to find the correct manual for it.   Is the jumper on the left the 2 ohm and the right 12?   So you add a jumper for the source?   

I do not see where the power feeds into it from the manual or how if connects to the different circuits.  They have a simple schematic and call out the values used.  They do not show the AC at all.   Is it basically just for the telcom industry? 

Ones I am used to can impose the wave on the AC.  L-L L-N L-G ....  It then synchronizes with the AC wave.    I think we can handle a 30A 4-wire circuit with ours and are limited to 300V for the mains.    To test the meters you would need to have the signal ride on the AC.    Imagine the fun!!

If it really is just the waveform,  it still has the potential to do far more damage than my homemade generator.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 22, 2015, 03:48:10 am
Imagine the fun!!
You're  >:D  >:D  >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 22, 2015, 05:44:29 am

Quote
101.4  Functional  integrity
After the voltage of  4.4.2.101  has  been applied to the  METER, the  METER  shall continue to be
able to indicate the presence of HAZARDOUS  LIVE  voltages up to the maximum RATED  voltage.

If this is relevant, then any meter you have failed before this video that also has a CATII rating or higher can't be sold in the EU legally. The ones that failed this video with a CATIII rating also cannot. It is my understanding, from watching a video by Martin Lorton at the Fluke facilities, that the US has no restrictions on the legal sale of multimeters, not yet.

There is another part that specifies that any meter should not fail in a way that could harm the user. I wonder how that is actually tested without putting a person in harm's way?


I have stated this a few times as well about the standards should be available for free if the concern is really with the public.   If you want a copy, they are available for purchase.   

The requirements are not clear in many areas. 
Quote
REASONABLY FORESEEABLE MISUSE
  These people have no idea what I consider reasonable misuse!


Quote
61010-2-033:2012
....
101 Measuring circuits
....
101.4 Functional integrity
After the voltage of 4.4.2.101 has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.
....
NOTE The METER is not required to maintain its normal accuracy. A maximum deviation of 10 % is acceptable.
....
Conformity is checked by inspection while applying the maximum RATED voltage of each
voltage measurement range capable of MAINS voltage measurements.
.....

4.4.2.101 Input voltages
For measuring circuit TERMINALS RATED for MAINS CIRCUITS voltage measurements:
.....

Note 4.4.2.101 does not talk about surge.   For that, refer to 14.101. 

Quote
14.101 Circuits or components used as TRANSIENT OVERVOLTAGE limiting devices in
measuring circuits used to measure MAINS

This is the section I read aloud in the one video.     

Quote
The test voltage is applied between each pair of TERMINALS, used to measure MAINS, where
voltage-limiting devices are present.
NOTE This test can be extremely hazardous. Explosion shields and other provisions can be used to protect
personnel performing the test.


Hopefully that answers your question
Quote
I wonder how that is actually tested without putting a person in harm's way?


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 22, 2015, 07:52:15 am
That was pretty funny!   Did you take the battery apart and find some small button batteries inside?
It rattled enough...

Your recommended Fluke 101 is holding up just fine so far.
I'd be surprised if it didn't. We know Fluke take the component layouts, track gaps, etc., very seriously. I suspect they left out the current measurement in the 101 because it's impossible to do a safe layout for a low-impedance path through a meter that small.

If your tests could make it fail much below its rating then you'd probably be getting a call from Fluke to investigate.

My only real complaints with this meter is how slow the continuity test is and the lack of a back light for the LCD.   
It's not a great meter for electronics work but it's a pretty good meter for an electrician, especially with the safety probes (which I don't think any of your other meters have).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 22, 2015, 05:08:08 pm
It's not a great meter for electronics work but it's a pretty good meter for an electrician, especially with the safety probes (which I don't think any of your other meters have).

Could you start by post a few pictures of what you are calling safety probes?   I'll post a few of what was included with the meters.   I suspect you have seen a different set of leads supplied with the 101 than what I received.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 22, 2015, 10:33:52 pm
It's not a great meter for electronics work but it's a pretty good meter for an electrician, especially with the safety probes (which I don't think any of your other meters have).

Could you start by post a few pictures of what you are calling safety probes?   I'll post a few of what was included with the meters.   I suspect you have seen a different set of leads supplied with the 101 than what I received.

And here you go.  Pictures of the Fluke 101, BK 2703C and the MASTECH probes.    I fail to see why the Fluke 101 probes would be considered a safety probe.     


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 22, 2015, 10:37:25 pm
And a last minute entry arrives all the way from China. 





Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 22, 2015, 11:13:29 pm
I am very interested to see how the UT139C behaves with your tests. I have been recommending it as a worthy meter for almost anything a hobbyist would need a meter for. It sure looks like it has proper input protection, so hopefully we will see!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 23, 2015, 12:07:22 am
I am very interested to see how the UT139C behaves with your tests. I have been recommending it as a worthy meter for almost anything a hobbyist would need a meter for. It sure looks like it has proper input protection, so hopefully we will see!

I have started testing again.  I see no point in setting up to run the lower energy transients to see where UT139C fails by comparison.   Rather I have meters that will pass my current levels so I plan to just test this one with them.   If it lives, it will stay with the meters that pass.  If it dies, we just know it was not a contender for the top $50 meter bracket.   

While the IEC  standard calls for a 1.2us rise/50us decay with an open and a 2 ohm source at 4KV, I again caution everyone that even though I am now testing at slightly over 3.7KV with a 50us decay into an open and with a 2 ohm source, there is no AC involved.   Do not consider these tests as any more than they are, pure entertainment and maybe some bragging rights. 

Another meter just failed...   RIP my friend.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on June 23, 2015, 01:09:48 am
You killed the Klein.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 23, 2015, 01:36:36 am
:-DD    I was not able to find the correct manual for it.   Is the jumper on the left the 2 ohm and the right 12?   So you add a jumper for the source?   

I do not see where the power feeds into it from the manual or how if connects to the different circuits.  They have a simple schematic and call out the values used.  They do not show the AC at all.   Is it basically just for the telcom industry? 

Ones I am used to can impose the wave on the AC.  L-L L-N L-G ....  It then synchronizes with the AC wave.    I think we can handle a 30A 4-wire circuit with ours and are limited to 300V for the mains.    To test the meters you would need to have the signal ride on the AC.    Imagine the fun!!

If it really is just the waveform,  it still has the potential to do far more damage than my homemade generator.

The generator that I use is for telecom.  This is not the one I use, but is in my lab. This generator pictured is "supposed" to be for IEC 61010 testing only.

There are 2 output jacks. You plug into the ones on the right for 12 ohm, and on the left for the 2 ohm output. There are two plugs for each output to allow two wires to handle the current, but keep the wire gauge down so they are flexible.  This machine does not allow AC into it, and is just the pulse. When they want to use AC with it, they put an inductor in the circuit between the AC and the pulse. But there is no syncing the pulse with the peak of the AC.  Since the spec say the maximum AC that the pulse can be riding on is 400V, I guess you could get the equivelant by just adding an additional 400V to the pulse and setting it for 4,400 or 6,400, or 8,400.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 23, 2015, 01:43:38 am
You killed the Klein.

 :-DD :-DD :-DD

Klein has that "Tougher Than" project.   Someone needs to link these videos for them and show them that there are a few people who actually are putting their product through an electrical test rather than having a chicken peck at it or an RC car drag it. 


Klein, tougher than Cen-Tech
Klein, tougher than Mastech
Klein, tougher than Gardner Bender
Klein, tougher than BK Precision
Klein, tougher than EXTECH

and the list grows.....

Just finished testing.  Included the new 139C in the mix.   3 of the 5 meters survived and you know the Klein Tools MM500 is right there on top.  Lot's of sparks and some nice part fragments to show for the last several hours.

And you people that think a meter is hard to design to handle this sort of punishment, well, there appears to be a few companies that can get the job done! 

I am afraid this is the end of the road for the toy generator.  The remaining three meters have taken everything I could throw at them.   It will take me some time to build something larger.   In the mean time, enjoy the videos.  I'll put the new ones up in a day or so.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 23, 2015, 02:49:49 am
And here you go.  Pictures of the Fluke 101, BK 2703C and the MASTECH probes.    I fail to see why the Fluke 101 probes would be considered a safety probe.     
OK, they have them as well...

Point is: Many cheap meters don't have decent probes.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 23, 2015, 03:47:15 am
And here you go.  Pictures of the Fluke 101, BK 2703C and the MASTECH probes.    I fail to see why the Fluke 101 probes would be considered a safety probe.     
OK, they have them as well...

Point is: Many cheap meters don't have decent probes.

Many cheap ones may not but we are looking at some high quality, low cost meters  :-DD :-DD

Top set is for the AMPROBE AM-510, center is from the Klein Tools MM500, lower is from the UNI-T UT-90A.   Personally, for what I would use a hand held meter for, these are all fine.  If I had to pick, it would be the BK probes.  Guessing they are made by the same company as the MASTECH but with the threaded end, I have some other tips that will work with them.

I like some of the Fluke probes and own one of their sets.   Second picture shows the probes I purchased for the attenuator versus my Fluke probes.   These work very well for probing fine pitch and other small parts.   They are CAT III 3A rated. 

Hope this helps.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 23, 2015, 02:45:13 pm
I think we can handle a 30A 4-wire circuit with ours and are limited to 300V for the mains.    To test the meters you would need to have the signal ride on the AC.    Imagine the fun!!

So, based on this comment, it seems your work has a more powerful machine than what you built up. Any chance you can put the 3 survivors on that?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 23, 2015, 05:13:35 pm
I think we can handle a 30A 4-wire circuit with ours and are limited to 300V for the mains.    To test the meters you would need to have the signal ride on the AC.    Imagine the fun!!

So, based on this comment, it seems your work has a more powerful machine than what you built up. Any chance you can put the 3 survivors on that?

Not really.   I would like the test the high dollar meter against the surviving $50 meter on a real setup.   

Videos are done processing.  Should be able to post them tonight.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Mark on June 23, 2015, 05:19:02 pm
Look what arrived today!  An 8kV surge generator. 

I thought I had some cheap-assed multimeters for sacrifice, but I now remember throwing them out... so the cheapest I have is a Maplin N72CG...  it is looking nervous. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 23, 2015, 05:43:01 pm
Now we are talking!   :-+   2 phase 16A model? 

You get it all running, I am curious how fast it charges in 8KV.   Ours takes about 20 seconds for 5KV.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 23, 2015, 07:18:20 pm
Well,

I hit a $5 Harbor Freight DMM with 12kV through 2 ohms today.  I was less than impressed by the failure.  Just a flash, with no flying components.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Mark on June 23, 2015, 10:05:44 pm
Now we are talking!   :-+   2 phase 16A model? 

You get it all running, I am curious how fast it charges in 8KV.   Ours takes about 20 seconds for 5KV.   

30 sec for 8kV and 15 sec for 4kV, haven't had time to do much more than that with it!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 24, 2015, 12:34:15 am
Good deal.  Starting to not feel so alone.   Let's see some video from these real generators doing the deed! 

Running the surviving four meters at 3.2KV.   WARNING!!!!  THIS IS A VERY NON EVENTFUL VIDEO!!!!  It's just there so you know I ran the test.
https://www.youtube.com/watch?v=q3Q_CiqXTh8 (https://www.youtube.com/watch?v=q3Q_CiqXTh8)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 24, 2015, 01:20:47 am
I am very interested to see how the UT139C behaves with your tests. I have been recommending it as a worthy meter for almost anything a hobbyist would need a meter for. It sure looks like it has proper input protection, so hopefully we will see!

And here you go.   The brand new UNI-T UT-139C is tested against the four remaining meters.  It had never been subjected to any transients compared with the others that have been through a small war.  It had the advantage.   

Three meters remain in full functional condition after this....
https://www.youtube.com/watch?v=kD5mxS_SkQk (https://www.youtube.com/watch?v=kD5mxS_SkQk)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on June 24, 2015, 02:09:02 am
Interesting that the UT90A only failed on the diode test. I figured that it would have fried the resistance measurenment as well.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 24, 2015, 02:25:40 am
Interesting that the UT90A only failed on the diode test. I figured that it would have fried the resistance measurenment as well.

Don't worry, I took care of it in the next round!!  :-DD 

Testing continues tonight at 5KV 2ohm 40uS (open).  Still 1KV off their rated, no AC and 10uS short.     

 One more meter was lost so far besides finishing off the UNI-T UT90A.   One has passed and the last one is being tested now.   We may have our winner tonight!!   



After hitting it a second time, I took this meter apart.  Next to the PTC, there is R46.  There is a VERY thin trace that routes from R46 to the switch.  Then from that same section of the switch to a via to a much wider trace.  The two sections of thin trace were vaporized. 


As it turned out, there were three very small traces that were vaporized.  I spent some time repairing them and tried the meter out.  Close but after looking further there is a part that appears to be shorted as well.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 24, 2015, 02:36:21 am
I am sorry to say that I have been unable to declare a winner.  The two remaining meters must actually handle the 61010 standard and stay functional.   

Klein Tools, tougher than UNI-T
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 24, 2015, 05:43:51 am
baby Fluke still alive?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 24, 2015, 11:15:51 am

Time to start thinking about what to do with so many non-functional meters.......
Buy/Sell/Wanted.   DMMs like new little used.  :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 24, 2015, 04:23:30 pm
I am sorry to say that I have been unable to declare a winner.

Can you ramp it up any higher? Keep going until one of them breaks.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 24, 2015, 06:54:24 pm
Harbor Feight DMM at 6kV blowing the input fuse.  Slo-mo

https://youtu.be/EeOvQ7VUYt8 (https://youtu.be/EeOvQ7VUYt8)

Harbor Freight DMM with fuse shorted, blowing the traces. Slo-mo

https://youtu.be/BOsekwQO68Y (https://youtu.be/BOsekwQO68Y)

Uni-T 201 clamp getting chip blown off board at 6kV. Slo-mo

https://youtu.be/mdLRPyt0ND4 (https://youtu.be/mdLRPyt0ND4)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 24, 2015, 08:16:57 pm
Interesting that the UT90A only failed on the diode test. I figured that it would have fried the resistance measurenment as well.

But, should ANY meter even be subjected to a 4kV surge on the diode test, resistance, or continuity?

The way I read 61010, surge testing like this should only be done on the MAINS measurement terminal. These tests are to simulate a lightning strike while measuring MAINS, or an inductive kick on the mains if power is broken from the serving transformer when that measurement is being taken. When would anyone ever see a 4kV, or greater, spike when doing a diode test or continuity.

Now, I realize Joe is testing these to see which meter can take his abuse the best.  But, I don't think any of us should expect a meter to see an 4kV spike (or survive one) when doing a diode test.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 24, 2015, 08:23:57 pm
As far as I understand the standards, every function is to be tested with every terminal.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 24, 2015, 08:58:33 pm
As far as I understand the standards, every function is to be tested with every terminal.

That's not the way I read the standards.

If the meter measures to 600V, then the standards require that the meter does not become a Hazard when 600V is applied to ANY terminal, and set on any dial position. So, I agree with your statement that Voltage should be applied to diode test, or the current jacks, etc.  This falls into the "reasonable misuse" of the meter category, where a user could have the meter on the wrong dial position, or plugged in the wrong jacks, and you go to measure a Voltage.

But, not the surge pulses.  The standard does not require you to handle 4, or 6, or 8kV when you are measuring a diode. This would never happen as a "misuse" of the meter, and you would never get a 8kV spike when measuring a diode.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 24, 2015, 09:29:14 pm
Have you tested the Fluke 101 yet?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: IanB on June 24, 2015, 10:44:41 pm
Now, I realize Joe is testing these to see which meter can take his abuse the best.  But, I don't think any of us should expect a meter to see an 4kV spike (or survive one) when doing a diode test.

It's worse than that. I think the chances of there being a 4 kV spike on the mains at the exact instant I am measuring the voltage is in the millions to one region. I would have more chance of winning the lottery than experiencing that event. Consider that in the half century of my lifetime there have been multitudes of devices plugged in to the mains 24 h a day in all the homes I have lived in, and none of them have experienced damage from such a surge. That's tens of thousands of hours of constant connection to the mains without such an event. Compare that to the maybe five minutes total I have spent probing the mains (assuming each measurement takes only a few seconds to make).

I think that for the industrial electrician, a professional tool is required that meets such standards.

For normal consumers in a home environment, such testing regimes are  totally out of proportion to the risk. Mandating such testing for consumer retail devices is simply forcing prices up unnecessarily.

(On the other hand, if a device is marked with a certain rating, then it certainly ought to be required to be compliant with those standards.)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 24, 2015, 11:50:03 pm
As far as I understand the standards, every function is to be tested with every terminal.

That's not the way I read the standards.

Unfortunately I do not have the full standards, and that is why I qualified the statement. Like I said before, the IEC is doing a big disservice by making the standards available for payment only. These are public safety standards and as such should be made publicly free so the average Joe can see them.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 25, 2015, 12:47:29 am
As far as I understand the standards, every function is to be tested with every terminal.

That's not the way I read the standards.

Unfortunately I do not have the full standards, and that is why I qualified the statement. Like I said before, the IEC is doing a big disservice by making the standards available for payment only. These are public safety standards and as such should be made publicly free so the average Joe can see them.

Attached is the section of 61010-2-033 that talks about testing for mismatch inputs. It only mentions applying voltage, not surges.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 25, 2015, 12:53:52 am
Now, I realize Joe is testing these to see which meter can take his abuse the best.  But, I don't think any of us should expect a meter to see an 4kV spike (or survive one) when doing a diode test.

It's worse than that. I think the chances of there being a 4 kV spike on the mains at the exact instant I am measuring the voltage is in the millions to one region. I would have more chance of winning the lottery than experiencing that event. Consider that in the half century of my lifetime there have been multitudes of devices plugged in to the mains 24 h a day in all the homes I have lived in, and none of them have experienced damage from such a surge. That's tens of thousands of hours of constant connection to the mains without such an event. Compare that to the maybe five minutes total I have spent probing the mains (assuming each measurement takes only a few seconds to make).

I think that for the industrial electrician, a professional tool is required that meets such standards.

For normal consumers in a home environment, such testing regimes are  totally out of proportion to the risk. Mandating such testing for consumer retail devices is simply forcing prices up unnecessarily.

(On the other hand, if a device is marked with a certain rating, then it certainly ought to be required to be compliant with those standards.)
If you're dealing with inductive loads you may also encounter spikes. Even a little DC relay can generate 300v spikes. https://www.youtube.com/watch?v=c6I7Ycbv8B8 (https://www.youtube.com/watch?v=c6I7Ycbv8B8)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 25, 2015, 01:14:38 am
As far as I understand the standards, every function is to be tested with every terminal.

That's not the way I read the standards.

Unfortunately I do not have the full standards, and that is why I qualified the statement. Like I said before, the IEC is doing a big disservice by making the standards available for payment only. These are public safety standards and as such should be made publicly free so the average Joe can see them.

Attached here is the section of 61010-2-033 that discusses the surge testing. This only discusses the function of the meter that tests MAINS, and only "IF" transient protection is used (because it is optional).  IF it is used, it can't fail, but it does not have to be used.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 25, 2015, 05:43:59 am
Consider that one of the principal partners of IEC is the WTO.   Are the standards more about trade restrictions and bureaucracy than safety?

"... shall operate as intended ..."  As a designer, we know MOVs have a limited life like all parts.  They can fail in a not so nice way.  I would say this is intended operation.     

Maybe ask your TUV safety inspector their take on it.  See if you can nail them down....  Use the word "safe" a lot too!   

Again, my goal is not to debate a spec that is filled with holes.   

As for how products are used,  I would never underestimate man's ability to do stupid things, myself included!     

If you're dealing with inductive loads you may also encounter spikes. Even a little DC relay can generate 300v spikes.

I agree that while I am using the IEC standards as a guideline for my waveforms, there is nothing in those standards about the countless transients you can see when working even on low voltage.   If you ever used the old door bell as a transient generator, you know where I am coming from.     Testing the meters this way does not mean that they would withstand all of the conditions you can come up with.  It may however indicate what companies have considered protecting their designs for such events.     Would I buy or recommend a meter than lives or one that fails?   If it were to a novice, I would suggest the most bullet proof meter I could find.    If they wanted more features and a less robust meter down the road, so be it.     

One thing this testing has shown me is that as a novice, you could buy a very robust meter for under $50!   

The meters I have are all being tested the same.   Not having it automated, and every meter being different, there are a few things that change and this is why I left the entire tests in the video.  It's not there because it is so exciting to watch, it there if someone were to question what had been done.   So not a lot of drama or fluff but at least it may provide people with some sort of real world testing to help them make a decision when it comes time for them to purchase a meter.   

 :blah: :blah: :blah:



Time to start thinking about what to do with so many non-functional meters.......
Buy/Sell/Wanted.   DMMs like new little used.  :-DD

Are you making an offer??!!   :-DD :-DD :-DD     

I am sorry to say that I have been unable to declare a winner.

Can you ramp it up any higher? Keep going until one of them breaks.


This has always been the plan.   Don't underestimate my ability to break things!   :-DD   Yea, I can ramp it up alright!     The key has been to make small changes.  Otherwise, they may have all failed at once and we would not really learn anything from the experiment.

So stay tuned!

Now, I realize Joe is testing these to see which meter can take his abuse the best.  But, I don't think any of us should expect a meter to see an 4kV spike (or survive one) when doing a diode test.

As far as the current testing is concerned, I would expect the next meter I purchase to handle at least a 4KV spike in diode test.  I am way beyond that now and a few meters are still fine...   

I can believe that manufactures would make arguments like this to side step the fact that their products are not as robust as a competitors.   This makes no difference to me.  The testing continues.....


Have you tested the Fluke 101 yet?

Both Danaher meters are in good hands....  :-DD   


Sorry for the long post.    The moment you have all been waiting for... The SEMI FINALS!!!!

https://www.youtube.com/watch?v=YqdCe23OKsQ (https://www.youtube.com/watch?v=YqdCe23OKsQ)


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 25, 2015, 05:54:28 am
Great! One question. What happened to the UT139C. Your last video ended before the end of the testing. Did I miss something?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 25, 2015, 06:14:51 am
There's only room for one meter at the top!   I have continued to modify the home made generator throughout this testing and it is on the brink of failure as it is now being pushed to 6KV in an attempt to take down one last meter!   More capacitors means less room and more Teflon has had to be added to prevent internal arcs.   I never expected any of these meters to survive the conditions I have put them through.   I think the ones that have really deserve my business.   No matter of my personally feelings about Fluke after buying my first one in the early 80's,  they have come a long long way to improve their designs if they can make a $50 meter survive the tests so far.   

I wish the Fluke's continuity function worked better and it had back light for the LCD.   

The same for it's brother, the AMPROBE.  Dang, it's one tough meter!  It has more features than the Fluke, like AC/DC current and NCV.   Not to mention that the continuity feature is fast and it has an LCD back light.   

One last test to run, one last video to make.   


Great! One question. What happened to the UT139C. Your last video ended before the end of the testing. Did I miss something?

So many videos, so much data, so little time.  I watched and no, you did not miss anything.  I must have edited it out or something.    :palm:   That was the best part of the whole video too!!!   So I won't spoil it for you.   Let me make a single video just for the 139C.   It will be worth it!




Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 25, 2015, 06:18:40 am
Thanks! I was surprised that the UT139C died. It looked very promising and I have one here. I was impressed by it but maybe not now.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 25, 2015, 06:32:29 am
It's not so much that it died, it is how it died.  The video will be well worth watching.   I'll get it up there in the next day.   

I was joking with a friend of mine about this experiment and I made the comment that every one of the meters I had bought for it was better than any hand held I had ever owned in my entire life.   I think when it comes to making a recommendation the best you can do is help educate people so they can make better choices. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 25, 2015, 08:17:44 am
It's not so much that it died, it is how it died.  The video will be well worth watching.
Shrapnel?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 25, 2015, 11:06:20 am
It's not so much that it died, it is how it died.  The video will be well worth watching.
Shrapnel?


I'm sure if I ran the real test with the mains, we would have had some real drama.   

Video is processing now...
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 25, 2015, 12:23:05 pm
Thanks! I was surprised that the UT139C died. It looked very promising and I have one here. I was impressed by it but maybe not now.

Here is the UNI-T UT-139C taking the hit.   Enjoy.
https://www.youtube.com/watch?v=2GjB3eUpDFY&feature=youtu.be (https://www.youtube.com/watch?v=2GjB3eUpDFY&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 25, 2015, 12:55:16 pm
Fluke meters at the low end are very spartan, they don't skimp on protection but the features take a back seat. But sounds like that Amprobe is a real winner though. I mean in that price range it's got a decent set of features and it can take the abuse.

Although Fluke 101 has its compact size going for it for a sort of a pocket meter.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on June 25, 2015, 01:15:56 pm
I was amazed that you killed the Klein, I liked its small size/lack of features.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 25, 2015, 05:01:52 pm
As far as I understand the standards, every function is to be tested with every terminal.

But the meter is not required to survive.

I can see some companies will want the meter to survive on AC volts range, for example, but on diode test they would just let the thing break inside safely as per the standards.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 25, 2015, 05:13:13 pm
Fluke meters at the low end are very spartan, they don't skimp on protection but the features take a back seat.
You say that like it's a bad thing.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 25, 2015, 06:27:26 pm
Thanks for the video. The failure of the UT139C seems to have been either a faulty PTC, bad spacing on the tracks that caused an arc over and then the failure of the PTC which then overloaded the MOVs too many times and then every time after the MOVs were a dead short and caused the big flashes.

If you are willing, I think it would make good videos investigating the failure mode of at least some of the meters and see if they could be repaired by just replacing a part or two.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 25, 2015, 06:42:18 pm
Fluke meters at the low end are very spartan, they don't skimp on protection but the features take a back seat.
You say that like it's a bad thing.
Heh, I am just thinking of people who are just getting into electronics and what to recommend to them, if I was on a tight budget for my first multimeter I would be hard pressed between the Amprobe and the F-101. I would most likely pick the Amprobe. For mid range meters and upper tier, definitely Fluke 87.

Amazon lists AM-510 at $37.88. Pretty impressive.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 25, 2015, 08:02:29 pm
Heh, I am just thinking of people who are just getting into electronics and what to recommend to them, if I was on a tight budget for my first multimeter I would be hard pressed between the Amprobe and the F-101.
The Fluke lacks current measurement. Definitely not good for electronics work (it's aimed more at electricians).

Amazon lists AM-510 at $37.88. Pretty impressive.
Yep. Seems like a nice meter for that price.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 25, 2015, 08:21:57 pm
It is not my intent to diminish the work and findings of joeqsmith with what I am about to say. His tests show one thing and one thing only, ie the ability of a meter to survive his pulse tests. This is something to consider when buying a meter but it is not the only criteria that a newbie should used in selecting a meter. It is still unclear whether a meter needs to survive and function after a test similar to this to be considered to have met the requirements of the IEC specifications for CAT ratings. It could be, and is my understanding, than multimeters only need to not harm the end user in this failure mode, with a pulse test. If this is the case, then all meters that did not harm the user in this test still meet their CAT ratings under the IEC rules.

The AM-510 is not a good meter just because it passed these tests, rather it is a good meter because it has the functions most needed and works as advertised and for a really good price. The fact that it passed these tests is just another point to consider but not necessarily the most important. I have not seen a full review of the AM-510 and have no direct experience with it. The assessment that it is a good meter, on my part, is that it appears to be well built and has the functions that are necessary for most people, and at a very good price.

I only write this to address the inexperienced or newbies who might take such an impressive set of videos and their dramatic results as being the main criteria for buying a multimeter and focus only that aspect. Safety is important, but none of these videos demonstrated an unsafe condition that I could see.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 25, 2015, 09:08:57 pm
I have some experience with $100 Amprobe meters and they are certainly of good quality. It's a decent brand. So I had my suspicion that Am-510 was going to pass the torture test. This just reaffirms it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 25, 2015, 09:17:24 pm
Amprobe seems to use three different manufacturers for their products, at least three. The AM-5x0 series seem to be made by Uni-T, at least that what has been speculated by some here on the forums. The AM-270, AM-140 and 160 are definitely made by Brymen. The others in the AM-2x0 series are not clear. The XR series were originally sold by other brands and bought out so I am not sure who actually makes those. The HD series is an unknown to me but they sure seem to be made tough.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on June 25, 2015, 09:51:16 pm
Amprobe seems to use three different manufacturers for their products, at least three. The AM-5x0 series seem to be made by Uni-T, at least that what has been speculated by some here on the forums. The AM-270, AM-140 and 160 are definitely made by Brymen. The others in the AM-2x0 series are not clear. The XR series were originally sold by other brands and bought out so I am not sure who actually makes those. The HD series is an unknown to me but they sure seem to be made tough.

The HD series I think are old Wavetek models (Amprobe acquired Wavetek and these are the leftovers from that acquisition). Not sure about the XR series, maybe these are wavetek too? Haven't looked into it enough
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on June 25, 2015, 09:55:35 pm
Not sure about the XR series, maybe these are wavetek too?
XR came from acquistion of Meterman.

Dave did a video review way back in eevblog #6 of the Meterman 37XR.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 26, 2015, 02:46:39 am
Hi Joe,

Since you are skilled enough to build your own generator, and have demonstrated coupling voltage with the surges, I could use your advice.

I want to couple AC voltage with the surge generator I pictured in this thread. I've researched what inductor should be used to couple this, and 1.5 mH seems the most common recommendation. But, I also want a inductor that can handle a considerable amount of current. So, I found a few 10A inductors, but not a 1.5 mH. In the 10A rating, they have a 1 mH, and a 2.5 mH.  Could you tell me which size inductor would be the best to use with the 1.2/50 pulse width?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 26, 2015, 03:59:14 am
It is not my intent to diminish the work and findings of joeqsmith with what I am about to say. His tests show one thing and one thing only, ie the ability of a meter to survive his pulse tests. This is something to consider when buying a meter but it is not the only criteria that a newbie should used in selecting a meter.

No problem. 

This may be all you took away from this experiment but there was a lot to learn.   I understand, you sell products like hand held meters.   I'm not suggesting you would ever add your own bias to make more sales.   You just need to make sure that you understand what is going on before you use this information as part of your sales pitch.   

Safety is important, but none of these videos demonstrated an unsafe condition that I could see.

That was never a goal.   Comments like this are why I don't think you really understand what can happen.    I covered this subject upfront.  If you don't feel that there are any concerns when an arc is combined with a high energy source, so be it.  Personally, I would not trivialize it to my customers. 

Thanks for the video. The failure of the UT139C seems to have been either a faulty PTC, bad spacing on the tracks that caused an arc over and then the failure of the PTC which then overloaded the MOVs too many times and then every time after the MOVs were a dead short and caused the big flashes.

If you are willing, I think it would make good videos investigating the failure mode of at least some of the meters and see if they could be repaired by just replacing a part or two.

There is no reason to spend a whole lot of time attempting to repair low cost devices like these.  Just buy a new one.   The goal was to find a meter that would survive, then you wouldn't need to be so concerned about replacing it.   I showed where most meters were damaged in the video.     

That said, I did waste some time repairing the UNI-T UT90A.  The control IC was still good.  Three traces had vaporized.  One diode was shorted, 2 resistors were open.  I aligned it and it seems fine.  Nothing I would give away because of the damage to the switch area. 

Sounds like you are most interested in the UT139C.     Q8, Q9, Q2, Q3, R42 and the main control IC are all damaged.    While the heat cracked the insulation around the one PTC, both of them are still fine.   

Most of the damaged meters were ran again at even higher voltages, causing even further damage to them.

I was amazed that you killed the Klein, I liked its small size/lack of features.
   

Klein Tools, not as strong as a set of channel locks!!  :-DD :-DD

The case is glued together.  Indeed, there is a relay in it.   I had attempted to contact  Klein, Fluke and AMPROBE by email.     I would have returned the Klein to them if they wanted it.  I am not sure what the problem is with it.  It appears the source was damaged, not the input.    I tested it again tonight after I ripped it (literally) apart.  It appears the PTC itself will not withstand the voltage.  It arcs and I am sure this caused the damage.    Of all of the meters, the mechanical design of this thing is fantastic, except you can not service it.   


Muxr and Fungus, I agree about the AMPROBE.  It really is a nice meter for the price.   I like it better than the Fluke.    I would like to have have a higher end Fluke, Keysight and AMPROBE to try and destroy (and I don't mean drop it).   

If I had any bias towards one brand during this test, it was with Fluke.   Again, I have to admit, this low cost Fluke really has changed my 30 year old view of their products.   Good job Fluke!!  :-+


Hi Joe,

Since you are skilled enough to build your own generator, and have demonstrated coupling voltage with the surges, I could use your advice.

I want to couple AC voltage with the surge generator I pictured in this thread. I've researched what inductor should be used to couple this, and 1.5 mH seems the most common recommendation. But, I also want a inductor that can handle a considerable amount of current. So, I found a few 10A inductors, but not a 1.5 mH. In the 10A rating, they have a 1 mH, and a 2.5 mH.  Could you tell me which size inductor would be the best to use with the 1.2/50 pulse width?

Sorry, I can't be of help other than suggest your life insurance is paid up.  I just don't know enough about it.  It's not just the current and inductance, that's a lot of voltage.    The company who built your generator may be willing to supply you with information on their networks.   You may find it better to get the right network for your system. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 26, 2015, 05:19:32 am
It is not my intent to diminish the work and findings of joeqsmith with what I am about to say. His tests show one thing and one thing only, ie the ability of a meter to survive his pulse tests. This is something to consider when buying a meter but it is not the only criteria that a newbie should used in selecting a meter.

No problem. 

This may be all you took away from this experiment but there was a lot to learn.   I understand, you sell products like hand held meters.   I'm not suggesting you would ever add your own bias to make more sales.   You just need to make sure that you understand what is going on before you use this information as part of your sales pitch.   

Safety is important, but none of these videos demonstrated an unsafe condition that I could see.

That was never a goal.   Comments like this are why I don't think you really understand what can happen.    I covered this subject upfront.  If you don't feel that there are any concerns when an arc is combined with a high energy source, so be it.  Personally, I would not trivialize it to my customers.

Your videos on the whole subject did provide much to learn on the subject of high voltages with high energy and the protection against them. I did not say that your videos were only about the ability of a meter to survive his pulse tests. I said that the tests of the meters only demonstrated that about the multimeters being tested.

I think you misunderstood my intentions and/or the meaning of my message. Because of this I also think you misunderstand my knowledge and experience with these kinds of things. I specifically said that these tests should not be the focus of buying a multimeter and that there are other considerations too. You yourself have said that these tests are not up to the standards required by the IEC and so I am merely saying that they should be considered incomplete to determine the safety of a multimeter. To be clear, the multimeters I distribute and sell are only Brymen, in most of South America, no where else, and no other manufacturer. I take safety seriously and my history here on the forums can vouch for that. Brymen also takes safety seriously. All of their current lineup meet the latest IEC requirements, and all are 3rd party tested by UL.

My message was to those looking to decide what multimeter to buy, as inexperienced and new comers to the hobby, and possibly thinking that your videos should be the sole focus for a purchasing decision. It is similar to a person focusing only on the accuracy specification on DC volts and not considering the other specifications that also make a big difference.

I also fully understood the goal of your tests and videos. I never said anything otherwise. I also fully understand the problems of safety and the serious nature of electrical hazards. To imply that I am trivializing the safety of my customers is to not understand what I have been doing here on the forums for years, and to not understand what I said in that post. I get the feeling that you have never read anything I have posted before on this subject except here in this thread. That could explain why you could accuse me of being casual on the subject of multimeter safety.

Thanks for the video. The failure of the UT139C seems to have been either a faulty PTC, bad spacing on the tracks that caused an arc over and then the failure of the PTC which then overloaded the MOVs too many times and then every time after the MOVs were a dead short and caused the big flashes.

If you are willing, I think it would make good videos investigating the failure mode of at least some of the meters and see if they could be repaired by just replacing a part or two.

There is no reason to spend a whole lot of time attempting to repair low cost devices like these.  Just buy a new one.   The goal was to find a meter that would survive, then you wouldn't need to be so concerned about replacing it.   I showed where most meters were damaged in the video.     

That said, I did waste some time repairing the UNI-T UT90A.  The control IC was still good.  Three traces had vaporized.  One diode was shorted, 2 resistors were open.  I aligned it and it seems fine.  Nothing I would give away because of the damage to the switch area. 

Sounds like you are most interested in the UT139C.     Q8, Q9, Q2, Q3, R42 and the main control IC are all damaged.    While the heat cracked the insulation around the one PTC, both of them are still fine.   

Most of the damaged meters were ran again at even higher voltages, causing even further damage to them.

Wow, that is a bunch of damage to the UT139C. It certainly looked like it was well protected but that is why multimeters need third party testing to prove their claims. Even then, all the damage and arcing was contained in the housing, from what I could see, so it is still not evidence that it didn't match its CAT rating. (Take note, I never have, and am not saying now, that you are claiming to verify the CAT ratings nor that your videos are to be taken as evidence for such a test)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 26, 2015, 02:08:15 pm
Sorry, I can't be of help other than suggest your life insurance is paid up.  I just don't know enough about it.  It's not just the current and inductance, that's a lot of voltage.   

I find that statement kind of funny, since it is coming from a guy who was doing his testing with the open meter a few feet away, and even changing switch positions while timing out the surges. At least I built a blast chamber made with half inch Lexan for my testing.

But, I get you not wanting to give advice if something went wrong on my end.  I would have not coupled through 400V.  I would have started with less than 100V, and put some 10A HRC fuses in line to limit any danger. The spec says that blowing the circuit breaker would be a failure to this test, so opening those fuses would be an indication of failure. That would help limit any danger.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 26, 2015, 06:00:42 pm
Sorry, I can't be of help other than suggest your life insurance is paid up.  I just don't know enough about it.  It's not just the current and inductance, that's a lot of voltage.   

I find that statement kind of funny, since it is coming from a guy who was doing his testing with the open meter a few feet away, and even changing switch positions while timing out the surges. At least I built a blast chamber made with half inch Lexan for my testing.

But, I get you not wanting to give advice if something went wrong on my end.  I would have not coupled through 400V.  I would have started with less than 100V, and put some 10A HRC fuses in line to limit any danger. The spec says that blowing the circuit breaker would be a failure to this test, so opening those fuses would be an indication of failure. That would help limit any danger.

These videos certainly do not show proper safety, nor was it my intent to ever do so.    The ring, watch, use of 2-hands, use of home made non certified probes, the list goes on.     Without the line voltage, I am working on sub 20J.   Still lethal but it's a very controlled event and I am comfortable working on things of this nature.    The thing you did not mention is that I posted once how I had stopped testing because I was burned out and started to make some mistakes.       

If you look at what goes into a normal CDN you will find there is more than just an inductor.   Our network is about 2X larger than the generator.    Even with our setup, there is enough energy going back on the line that we have damaged other equipment in the lab.     

Yes, I did run a simple experiment using a single inductor to isolate a supply from the transient.  It was a very scaled down test.   I would hope the thing people took aware from this was how the arc started the event and the lower voltage sustained it.   Not that a simple inductor was all that was needed to isolate a real surge from the mains.   

One thing to consider is what tests should be ran to determine how electrically robust a multimeter is?  Sure dropping it, putting it into a bucket of water and plugging it into your AC outlet are all easy tests to perform but really it seems there should be some sort of standards the products could be tested to besides surge.   

The  IEC surge was the closest thing I could come up with.   As I noted, I dialed it way down lower than the IEC calls for and worked my way up.   Sure it does open the doors for people to read the standards are argue that they only need to fail safe.   :blah: :blah: :blah:   There are going to be people that don't get the point of the test.   

Again, I have no idea if the meters really would fail in such a way as not to meet the IEC standards.  If you want to know this, I would suggest you run them at an accredited lab.   This was not the intent!   If you want to know if one meter is more robust than another, I think the tests I have ran give a fair idea.   If you feel that the testing I performed is not an indicator of this, you are free to come up with your own tests and post them.     I would be very interested and welcome this and am sure others would be as well.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 26, 2015, 06:12:24 pm
The thing you did not mention is that I posted once how I had stopped testing because I was burned out and started to make some mistakes.         
That certainly must have taken a lot of time to do. I certainly enjoyed the experiment and I appreciate you sharing it with us.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 27, 2015, 12:28:37 am
Here is a video I found on Fluke's testing lab, and all the tests they do.  The surge and over voltage testing are at the very end.

http://assets.fluke.com/video-MULTI/44095317_fluke_safety_lab.html (http://assets.fluke.com/video-MULTI/44095317_fluke_safety_lab.html)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on June 27, 2015, 02:29:16 am
I can also say that I enjoyed them too. I think many people were grateful for your time and expense that put forward for the benefit of all.  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 27, 2015, 10:00:28 pm
I can alssay that I enjoyed them too. I think many people were grateful for your time and expense that put forward for the benefit of all.  :-+

 :-+

It would have been nice to run comparisons like this on more meters but I think going forward I'll leave this to others with more resources available to them.   

I still plan to put the winner up against the Fluke 28 II and/or the Keysight U1272A and at least see of one of these meters can withstand the testing that the low cost meters have.   My fear is that some of the $50 meters may actually hold up better and I may damage a meter costing more than the entire amount spent so far.     

It's been almost one month to the day since I started looking into running this experiment.  Enjoy the finals....

https://www.youtube.com/watch?v=RBkjr3b5hQo&feature=youtu.be (https://www.youtube.com/watch?v=RBkjr3b5hQo&feature=youtu.be)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: John Coloccia on June 27, 2015, 10:32:04 pm
"Looks like a hazardous condition to me"

 :-DD :-DD :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 27, 2015, 11:15:13 pm
Good stuff Joe! That intro was fun.

If I was Fluke I would send you a new 28-II or an 87V  ;D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: siggi on June 27, 2015, 11:29:15 pm
Great videos, nice objective robustness criteria. Sure beats "feels solid", "better feeling plastic" reviews :).
I didn't care much for the DMM scat, but to each his own.


Sent from my iPad using Tapatalk
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 27, 2015, 11:48:47 pm
 :clap:  :-+

Gotta love your evil lady.  >:D

Great job Joe, it'll be interesting to see if any manufacturers contact you with revised models for you to retest.  :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 28, 2015, 12:45:00 am
Great job Joe!!

Now that I know the top meter, I wouldn't mind getting the Fluke 101, and see how much higher it can go. Now, I wouldn't have to buy 10 meters like you did, I could get just the one.  It would be interesting to see how far beyond 6kV it could go, since I could take it all the way to 12kV.

Too bad none of the companies you contacted got back to you. Since Fluke was the winner, it would have been nice for them to send you something else. Maybe they still will. But, it sucks that no companies even acknowledged you emails.

You should consider selling those boxes. Like you said, they go for 10's of thousands.  You could make a killing selling yours to people who can't afford the big ones.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on June 28, 2015, 03:58:06 am
Thanks for all of the work you have put into these test, thumbs up from me.  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ivan747 on June 28, 2015, 04:39:51 am
Thank you for sharing your findings and involving us in the process too.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on June 28, 2015, 12:04:26 pm
I second this wholeheartedly.  Great job. :clap:

More later, but one thing you could use your surge generator for doing the exact same tests are evaluating surge protectors, they are more improperly built compared to DMMs and have similar input protective circuitry.  However the let-through voltages are lower on the MOVs and they are more subject to burn violently as they can be exposed to sustained overvoltages caused by say, lost-neutral events, as in the way home distribution is done in the USA.

Its used by a wider audience and models are introduced very often, you can make a business, or at least an endless series of review videos, checking them.

https://www.eevblog.com/forum/suggestions/surge-protectors-scams-and-saints/msg3891/#msg3891 (https://www.eevblog.com/forum/suggestions/surge-protectors-scams-and-saints/msg3891/#msg3891)


Great job Joe!!

Now that I know the top meter, I wouldn't mind getting the Fluke 101, and see how much higher it can go. Now, I wouldn't have to buy 10 meters like you did, I could get just the one.  It would be interesting to see how far beyond 6kV it could go, since I could take it all the way to 12kV.

Too bad none of the companies you contacted got back to you. Since Fluke was the winner, it would have been nice for them to send you something else. Maybe they still will. But, it sucks that no companies even acknowledged you emails.

You should consider selling those boxes. Like you said, they go for 10's of thousands.  You could make a killing selling yours to people who can't afford the big ones.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dom0 on June 28, 2015, 10:30:30 pm
Niiiicee!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: patw4pbj on June 29, 2015, 03:49:51 am
Fun and educational thread.  Thanks.


Sent from my iPad using Tapatalk
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 29, 2015, 11:22:08 pm
Thanks for all of the kind words.

A few things I would like to add.   There has been some debate about if a meter would need to be functional after surge testing or not.  I have heard from some manufactures who say they do not.   I have no idea and would have to ask.  However, I did find this series of videos on-line that Fluke put out.

http://download.fluke.com/video-safety/flukesafetyvideo.html (http://download.fluke.com/video-safety/flukesafetyvideo.html)

Watch the video "Meter Testing".   It will talk about the surge testing.   I typed in what I believe was stated in the video:   

“A special test machine is used to generate the over voltage transient and fault current as defined by national and international standards.  This meter is marked 1000 volts CAT III on the front of the case.  More importantly it has been certified by an independent testing laboratory.   A 1000 volt category three tester is require to survive a minimum of ten transients of both positive and negative 8000 volts without being damaged or creating a hazard.  Fluke goes a step further in designing and building our test tools for your safety.   With stout input protection and high energy fuses, our meters are built to survive.

As a short test we have programmed our test machine to increase the transient voltage in steps until the meter fails. 6000 volts, 9000 volts, 12,000 volts, 15,000 volts, 17,000 volts ……”   
 

Now I guess there is still room for interpretation but it seems pretty clear to me what Fluke requires.    Again, I am not testing to these standards and don't really care what is required.

As I mentioned in the last video, I spent some time looking at the UT90A after it was damaged.    Below are pictures showing the damage. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 29, 2015, 11:27:09 pm
I also looked at the AMPROBE AM-510.   Only one transistor had failed.   I looked through the carnage of meters and the M7 1000V diodes and H1A transistors were on other meters.   I pulled and tested them and rebuilt the two meters (no point using new parts).   These two meters now work very well.   



Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 29, 2015, 11:51:43 pm
The circuit boards were removed and sent to be recycled.   Here is all that remains.     

I have continued to attempt to contact both Fluke and Keysight to see if they will warranty their meters during the testing.  Finding just an email address has proven to be a problem.   Keysight seems to just want my info (some automated BS thing) and while Fluke has now responded, I have yet to get an answer.   For now, the next phase of testing is on hold.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on June 29, 2015, 11:58:01 pm
Quite the carnage ;D

Good job on the repaired ones.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 30, 2015, 12:47:22 am
Quite the carnage ;D

Good job on the repaired ones.


These were the only ones left that the control IC was not damaged.   Had I not fried them with the neon sign transformer, shot at them with arrows, used Dave's Dremel technique to attempt to repair them and rezapping them over and over again with my generator,  more could have been saved.     But really, which would have been more pointless?  :-DD

It was easy to align them both.  The AMPROBE has 4 pots.  It has a separate one for DC volts, AC volts, current and capacitance. 

Someone had asked on youtube what source was used.  The last test was with 2 ohms as well.   

The Fluke 101 and transient generator will remain untouched until the next test.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on June 30, 2015, 01:46:13 am
Had I not fried them with the neon sign transformer, shot at them with arrows, used Dave's Dremel technique to attempt to repair them and rezapping them over and over again with my generator,  more could have been saved. 

Yeah, it looked like the Klein just needed a new PTC, but the case was so trashed, what's the point?

The Fluke 101 and transient generator will remain untouched until the next test.

What's the next test?  You taking the generator up to 8kV??  Or, are some of these companies giving you higher end meters to test??
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 30, 2015, 03:16:55 am

Yeah, it looked like the Klein just needed a new PTC, but the case was so trashed, what's the point?

What's the next test?  You taking the generator up to 8kV??  Or, are some of these companies giving you higher end meters to test??

The Klein case was fused.   The PTC and resistor were fine on it (for low voltage).   When it arc'ed over, something further down the chain was damaged.   I may have attempted repairs if it were designed to be serviced rather than disposable.   

As far as the next test, it's still the same.   If you watched that last video I mentioned, we may be looking at 16 - 17KV to get the job done.    :-DD     You mentioned you may purchase a 101 to run on your system at work.   If you do, post the results. 

To be clear, I am not looking for the companies to give me anything except to warranty the higher end meter it if it fails first.  Seems pretty trivial.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 30, 2015, 07:36:23 am
Thanks for all of the kind words.

You've put in a lot of work and generated some useful data for the world.

A few things I would like to add.   There has been some debate about if a meter would need to be functional after surge testing or not.  I have heard from some manufactures who say they do not.   I have no idea and would have to ask.  However, I did find this series of videos on-line that Fluke put out.

I don't think the standard requires it.

Quote from: fluke
“Fluke goes a step further in designing and building our test tools for your safety.   With stout input protection and high energy fuses, our meters are built to survive.”   
 
Now I guess there is still room for interpretation but it seems pretty clear to me what Fluke requires.
The conclusion (yet again) is that Fluke hold themselves to a higher standard than what's required to get the official rubber stamp of approval.

Now.... if only their fuses weren't so expensive to replace and they could figure out how to make meters that start up in DC mode instead of AC. Then they'd be perfect.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 30, 2015, 12:02:59 pm
Quote from: fluke
“Fluke goes a step further in designing and building our test tools for your safety.   With stout input protection and high energy fuses, our meters are built to survive.”   
 
Now I guess there is still room for interpretation but it seems pretty clear to me what Fluke requires.
The conclusion (yet again) is that Fluke hold themselves to a higher standard than what's required to get the official rubber stamp of approval.

Now.... if only their fuses weren't so expensive to replace and they could figure out how to make meters that start up in DC mode instead of AC. Then they'd be perfect.




Quote
A 1000 volt category three tester is require to survive a minimum of ten transients of both positive and negative 8000 volts without being damaged or creating a hazard.
  Then they go on to say "..Fluke goes a step further ..."   Followed by a demonstration of the meter  running up to 17KV before failure.    So yes,  I agree with your comment that Fluke does hold themselves to a higher standard as 17KV is much higher than the 8KV required for the CAT III 1000V meter being shown.    Their words, not mine. 
 :-//   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on June 30, 2015, 12:22:29 pm
Seems quite clear to me, Fluke are very prepared to stand by their reputation, no need for company name changes and the like.  :-+
Something like "We are Fluke, we make good stuff, beat us if you can".  :popcorn:

Not that I've had lots to do with Fluke, I've sold a number of 15B's, got an extra one for personal use and been rapped with it. That's about a $70 unit and all I need for a HH DMM.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 30, 2015, 12:49:36 pm
I've sold a number of 15B's, got an extra one for personal use and been rapped with it.
Somebody rapped you with a Fluke? Knuckles or head? Either way it sounds nasty.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on June 30, 2015, 12:51:32 pm
So yes,  I agree with your comment that Fluke does hold themselves to a higher standard as 17KV is much higher than the 8KV required for the CAT III 1000V meter being shown.
17KV is much higher than the 12KV required for CAT IV 100V rating.

(And I'm sure most other manufacturers would have gone with the higher rating...)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 30, 2015, 04:58:38 pm
So yes,  I agree with your comment that Fluke does hold themselves to a higher standard as 17KV is much higher than the 8KV required for the CAT III 1000V meter being shown.
17KV is much higher than the 12KV required for CAT IV 100V rating.

(And I'm sure most other manufacturers would have gone with the higher rating...)

I assume you meant CAT IV 1000.  Note that the meter in the video is not CAT IV 1000.   It is CAT III 1000/ CAT IV 600, both require 8KV 2ohm 8/20 which is what they state.    Are you looking at a different video perhaps?

I have asked Fluke about the video I linked.  We will see if they get back with to me with an answer.   

Started to look at the specs for the Keysight and Fluke meters in detail and downloaded the manuals.    I had no idea the 28II did not support AC+DC RMS.   The 287/9 are not CAT III rated.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on June 30, 2015, 08:30:54 pm
The 287/9 are not CAT III rated.
???

A picture from the manual shows it 1000V CAT III rated.  Or am I misinterpreting your statement?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on June 30, 2015, 11:23:31 pm
The 287/9 are not CAT III rated.
???

A picture from the manual shows it 1000V CAT III rated.  Or am I misinterpreting your statement?

Good catch!

 :-//  I had gone to Amazon to get a price and the first one that came up was:
Quote
http://www.amazon.com/Fluke-287-Electronics-Multimeter-TrendCapture/dp/B0015PMU8E

and saw
Quote
Specifications include European Conformity (CE) marking, UL, CSA, IEC safety standard 61010 and is certified for Category I installations up to 1000V and Category II installations up to 300V

This appears to be a much better meter for my needs.   I'll get the manual for it.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 01, 2015, 03:06:09 am
Just keep in mind Fluke 287/9 series have that annoying leaky super cap problem. Don't know if it's been resolved yet.

If you're thinking of getting an upper tier Fluke meter, for day to day use, you might like the 87V better due to a streamlined interface and good battery life or since you work with high voltages a lot, 28/II is practically the same meter (feature wise) but in a super rugged case (that's not to say that 87V isn't industrial).

87V and 28/II are in my opinion the two best hand held meters Fluke make. I enjoy the 87V form factor better since it's smaller. But 28/II is a tank and it uses AA batteries.

287/9s have more features but in my opinion it takes away from the ergonomics and the battery life a go to meter should have. Data logging and higher resolution can be nice though.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 01, 2015, 03:58:24 am
I like the 28II and 87V, if they would just measure AC+DC RMS.   

Watched a few reviews of the 287 and that battery life is killer.   I don't care for the slow boot times or the display.   Seems they just don't quite have what I want.   

The Keysight may be a better fit but I did not care for the UI on it.   Let me keep looking.   

Maybe the 87IV was not popular.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on July 01, 2015, 05:37:30 am
But 28/II is a tank and it uses AAA batteries.
The 27 II and 28 II both use three AA cells for approximately 800 hours.  Eneloops work fine in them.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on July 01, 2015, 05:42:28 am
Maybe the 87IV was not popular.
The battery life of the 87IV/89IV/187/189 is only 72 hours with 4 AA.  I have a 187 and use Eneloops with it.  So battery life isn't an issue as I always have Eneloops charged and ready to go.

PS. The 87IV/89IV/187/189 is discontinued so the only way to buy it is used and obviously you won't get any warranty from Fluke should you try your experiments on it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 01, 2015, 10:29:29 am
But 28/II is a tank and it uses AAA batteries.
The 27 II and 28 II both use three AA cells for approximately 800 hours.  Eneloops work fine in them.
Duh I just replaced them last week and you'd think I'd remember. Thanks for the correction(s).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 01, 2015, 01:09:09 pm
17KV is much higher than the 12KV required for CAT IV 100V rating.
(I'm sure most other manufacturers would have gone with the higher rating...)
I assume you meant CAT IV 1000.
Yes.  :-[

Note that the meter in the video is not CAT IV 1000.
I know, but if they test them to 17000V then they could easily label it "CAT IV 1000V". For some reason they don't (maybe that would need better probes or something and push the price up, or maybe they just like to leave a safety margin on their ratings).


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 01, 2015, 07:12:09 pm
I know, but if they test them to 17000V then they could easily label it "CAT IV 1000V". For some reason they don't (maybe that would need better probes or something and push the price up, or maybe they just like to leave a safety margin on their ratings).

Labeling a meter CAT IV 1000V isn't "just" about meeting the 12kV surge requirements.  Having that rating means much harder creepage and clearance requirements too.  Maybe they meet the surge, but not the clearance, and that is good enough for them, so they are happy with the CAT IV 600V rating.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 02, 2015, 05:47:26 am
I had read https://www.eevblog.com/forum/projects/cat-ratings-and-interpretation/ (https://www.eevblog.com/forum/projects/cat-ratings-and-interpretation/).  Dated but I believe there is still no clear answer.   I contacted two different handheld meter manufactures to get their take and was given two different answers.      If the companies themselves are not clear on the requirements, I doubt any of us are going to arrive at the same conclusion.   The companies who take that stance that their meters must remain functional are most likely going to produce a more robust product.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 02, 2015, 07:31:23 am
Cranked up the generator to 6.5KV 40uS into an open using the 2 ohm source.   The waveform is attached.  This is about 700 volts over what I had the two final meters at.   I then repeated the test using the Fluke 101 all modes, both +/-.   Once again, the Fluke remains fully functional.     The more I beat it up, the more impressed I am.

This really is the limit of the generator.   There is no room inside to add more storage and pushing it harder is just going to damage it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 02, 2015, 02:02:34 pm
Cranked up the generator to 6.5KV 40uS into an open using the 2 ohm source.   The waveform is attached.  This is about 700 volts over what I had the two final meters at.   I then repeated the test using the Fluke 101 all modes, both +/-.   Once again, the Fluke remains fully functional.     The more I beat it up, the more impressed I am.

This really is the limit of the generator.   There is no room inside to add more storage and pushing it harder is just going to damage it.

What voltage are the caps in your bank rated for?  Couldn't you charge them with the output of that neon sign transformer that you used for your Jacob's ladder?  That way, you would need to get your internal DC converter to put out a higher voltage.  You would just need to limit what level you charged the caps to.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 02, 2015, 03:31:00 pm
Cranked up the generator to 6.5KV 40uS into an open using the 2 ohm source.   The waveform is attached.  This is about 700 volts over what I had the two final meters at.   I then repeated the test using the Fluke 101 all modes, both +/-.   Once again, the Fluke remains fully functional.     The more I beat it up, the more impressed I am.

This really is the limit of the generator.   There is no room inside to add more storage and pushing it harder is just going to damage it.

What voltage are the caps in your bank rated for?  Couldn't you charge them with the output of that neon sign transformer that you used for your Jacob's ladder?  That way, you would need to get your internal DC converter to put out a higher voltage.  You would just need to limit what level you charged the caps to.

The caps (storage) are the limiting factor.   Are you going to run the 101 on your 12KV setup?   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 02, 2015, 06:25:49 pm
The caps (storage) are the limiting factor.   Are you going to run the 101 on your 12KV setup?

The 101 is due today..........
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 02, 2015, 07:10:14 pm
 :-+  :-+ 


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 02, 2015, 11:37:34 pm
The 101 arrived, and I tested it after I got off work. 

The unit survived the full 12kV!!  I hit it 3 times, each polarity, on all switch settings. Everything was fully functional, as I tested every single position.

I actually started at a lower level, an not right a 12kV.  I hit it 3 pulses of each polarity at 6, 8, 10, and then 12kV.  After the Fluke passed all of that, I blew up another $5 Harbor Freight meter, just to prove to myself everything was working.

I recorded the testing, but there is no point in posting it, as NOTHING happened.

I also took a short video of the inside of the surge generator, so everyone can see it's construction. I'll post a link as soon as it finishes uploading.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 02, 2015, 11:45:29 pm
Here is a quick video of the inside of the surge generator. I'm assuming that people following this thread would be interested in it's construction.

I just stuck the GoPro camera in, and moved it around to show the capacitor banks, transformer, control panel, and massive contactor.

http://youtu.be/bifNjReS_Yw (http://youtu.be/bifNjReS_Yw)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 02, 2015, 11:57:48 pm
Nice construction. Looks roomy.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 01:08:38 am
The 101 arrived, and I tested it after I got off work. 

The unit survived the full 12kV!!  I hit it 3 times, each polarity, on all switch settings. Everything was fully functional, as I tested every single position.

I actually started at a lower level, an not right a 12kV.  I hit it 3 pulses of each polarity at 6, 8, 10, and then 12kV.  After the Fluke passed all of that, I blew up another $5 Harbor Freight meter, just to prove to myself everything was working.

I recorded the testing, but there is no point in posting it, as NOTHING happened.

I also took a short video of the inside of the surge generator, so everyone can see it's construction. I'll post a link as soon as it finishes uploading.

 :-DD :-DD I was afraid of that!   Fungus called this one!

So we are all clear, I have a few questions.

Are you using the 1.2/50 8/20 surge, 2 ohm source?
Was there any sort of bias on the meter when you hit it with the transients?   
Did you verify the waveform?   

And of course, what's it going to take to damage one of these!!??   It's a cheap $50 meter, how hard can it be?? 




Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 03, 2015, 01:40:25 am
That's pretty incredible 12KV!!

You know when Dave Taylor did the AmpHour interview about the history of Fluke. He mentioned how Fluke invested millions in just their PCB washing process. I thought it was a great anecdote on how seriously they take safety and quality.

It's good to see that even their Chinese made 101s are continuing that tradition. I am definitely impressed. Thank you for great tests Joe and Meter Junkie!

Here is the link to the AmpHour episode in question: http://www.theamphour.com/180-an-interview-with-dave-taylor-multi-talented-meter-maker/ (http://www.theamphour.com/180-an-interview-with-dave-taylor-multi-talented-meter-maker/)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 01:44:34 am
:-DD :-DD I was afraid of that!   Fungus called this one!

So we are all clear, I have a few questions.

Are you using the 1.2/50 8/20 surge, 2 ohm source?
Was there any sort of bias on the meter when you hit it with the transients?   
Did you verify the waveform?   

And of course, what's it going to take to damage one of these!!??   It's a cheap $50 meter, how hard can it be??

Yes, it was a 1.2/50   8/20 surge.  That is the only wave this machine does, as it was designed exclusivley to test 61010-1.  And yes, I was using the 2 ohm output, not the 12.  I was also only using about 4 inch leads into the meter, instead of the full length of the leads, to lower the resistance as much as possible.

No bias. I am looking into a CDN, but do not have one yet.  I doubt a bias would have done anything, as there was no arcing at all during the surge testing. Yes, it would add continuous energy after an arc started, but I don't believe there was any arcing.

I did not verify the waveform.  I do not have a high voltage probe for my scope. But, this machine is calibrated, and the waveforms verified during calibration.

It looks like Fluke may be true to it's claim that these meters will survive upwards of 17kV.  I'm going to open the Fluke, and see what MOV's they are using, and what type of capacity they have. Maybe they can clamp these levels.  It looks like someone my need to build a 20kV generator, or increase the length of the pulse to kill these with a surge.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 02:38:15 am
:-DD :-DD I was afraid of that!   Fungus called this one!

So we are all clear, I have a few questions.

Are you using the 1.2/50 8/20 surge, 2 ohm source?
Was there any sort of bias on the meter when you hit it with the transients?   
Did you verify the waveform?   

And of course, what's it going to take to damage one of these!!??   It's a cheap $50 meter, how hard can it be??

Yes, it was a 1.2/50   8/20 surge.  That is the only wave this machine does, as it was designed exclusivley to test 61010-1.

No bias. I am looking into a CDN, but do not have one yet.  I doubt a bias would have done anything, as there was no arcing at all during the surge testing. Yes, it would add continuous energy after an arc started, but I don't believe there was any arcing.

I did not verify the waveform.  I do not have a high voltage probe for my scope. But, this machine is calibrated, and the waveforms verified during calibration.

It looks like Fluke may be true to it's claim that these meters will survive upwards of 17kV.  I'm going to open the Fluke, and see what MOV's they are using, and what type of capacity they have. Maybe they can clamp these levels.  It looks like someone my need to build a 20kV generator, or increase the length of the pulse to kill these with a surge.

Good enough on the waveform.    What sort of rep rate were you hitting it at?   

I had asked Fluke about how the 101 stacked up against the 28II.  They responded with "The Fluke 28II is more robust than the Fluke 101 (which is only sold in Asia) and has a limited lifetime warranty."     Also, I asked them if they would release the test data for the 101.  They would not.   

I just finished up the generator.   Second box now contains the storage only.  They are bolted together as I don't think I want 10KV wires dangling around.    :-DD   Supply, trigger and network are on top.     We will see if that 101 can handle this.      Note the decay and amplitude now.   

If it lives through this, I think I need to throw in the towel and just admit, I am not tougher than my $50 Fluke!   :-DD

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on July 03, 2015, 02:40:04 am
I can't wait for a test video.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 02:53:35 am
What sort of rep rate were you hitting it at?   

I was hitting it as fast as the generator would charge, which was about 15 to 20 seconds to get to the full 12kV.  I went similar to what you were doing......started at AC voltage on the left of the dial, hit with 3 positive pulses, moved the dial to the right.  Hit all the modes on combo positions (ohms, continuity, diode). When I got to the end, I reversed the polarity, and went back right to left.

The video of me hitting the 12kV was a total of 12 minutes long, with all the pulses as described above.  If I have time this weekend, I will move it off the GoPro camera, speed it up so it's not 12 minutes, and post it.  It just seems like a waste, because it is just me changing dial positions, and hitting the discharge button.  No good blast to see, or hear.

Good luck with your 10kV testing (looks closer to 12kV on that waveform).   Based on my testing, you will be quite bored.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 03:52:18 am
i just logged into work to look at the documentation for our generator.  We store everything on our servers.  When the unit shipped to us, they provided waveforms of the unit from their test lab. Attached is the 12KV waveform.  The decay on this is much larger than your waveform. The measurement must not be from peak, but from one percentage to another.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 04:04:05 am
here are shots of where they set their markers to determine rise and fall.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 04:16:03 am
The video of me hitting the 12kV was a total of 12 minutes long, with all the pulses as described above.  If I have time this weekend, I will move it off the GoPro camera, speed it up so it's not 12 minutes, and post it.  It just seems like a waste, because it is just me changing dial positions, and hitting the discharge button.  No good blast to see, or hear.

Good luck with your 10kV testing (looks closer to 12kV on that waveform).   Based on my testing, you will be quite bored.

Yes,  its a full out 12KV.   Should have wrote thousands of volts dangling around.    Most of those tests I ran were VERY boring.   On the plus side I did explode a CC resistor and took out a 120V light bulb.    The first transients I had would take out a very tiny bulb.  The later ones could damage the larger automotive bulbs.   Good to see it finally be able to take out a 120 V one!    :-DD     

Looking at your waveform, you are already beyond what I have now.   I'll run it anyway.   At least then we have two meters that have been tested roughly the same.

Guessing that was a custom unit for Fluke.   Even using salvaged parts, building one in the 20KV range is going to cost more than the Fluke 28II.   I think if this 101 lives, I will just admit, Fluke really is the king of meters!   :-DD     Well that is unless someone wants to send us a couple of other brands to run through this test to prove it otherwise.   I don't think you will find a whole lot of even more expensive ones that are going to take this sort of abuse!     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 04:22:28 am
I think we are close on Tr.   I may be able to get a little more out of it.   Been too long of a day to do anything now.    :=\        I'll start with what I have, if that lives, Ill see how far I can push it with the new setup.   

Where is Fluke going to ever find free marketing like this!!  :-DD   Especially coming from someone who admittedly has not been one of their fans.     

So let me get some rest and then I will take one last crack at it!   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 02:20:20 pm
Joe,

I looked back at that document you posted on page 2 of this thread.  It was from Advanced Energy on building and testing surge generators.  That document shows the pulse length markers from the 50% amplitude on the rise, to 50% on the fall.  It matches the waveform from my generator dead on.

If you look at your latest waveform compared to that document, your decay pulse is more like 20 uSec, instead of the 50 you want. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 03:46:25 pm
Here is the video of me surging the Fluke at 12kV.  Boring as hell.  I left it normal speed at the beginning and end, so you can see the charge times, and here the contactor relay firing.  5x speed the for the rest of it.

It is not as clear as Joe's video, as I was trying to keep both the generator and meter in the picture, and still have some safety separation.  You can see the display change, and sometimes show O.L. after the hits, but that would clear on the next hit, or selector switch change.  I verified it was 100% functional after the hits.

http://youtu.be/4hk5Vmf65-4 (http://youtu.be/4hk5Vmf65-4)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 03:58:49 pm
Guessing that was a custom unit for Fluke.     

Found what looks to be that model on-line.  The specs say it can go to 33 kV, and deliver 30 kA.  I don't even want to know what a machine like that costs.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 04:32:28 pm
Joe,

I looked back at that document you posted on page 2 of this thread.  It was from Advanced Energy on building and testing surge generators.  That document shows the pulse length markers from the 50% amplitude on the rise, to 50% on the fall.  It matches the waveform from my generator dead on.

If you look at your latest waveform compared to that document, your decay pulse is more like 20 uSec, instead of the 50 you want.

They use FWHH to measure peak shape.   I am using the 100/0 which I thought was very clear from all of the scope shots.  But then I have made statements about how it compares with 61010 so I can see how I clouded things up.   

Still it's not a big deal.  I'm starting to sound a bit like a broken record but again, I was not too concerned about what I hit the meters with, as long as they were all tested the same.  Again, I am not trying to certify the meters for CAT III. 


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 08:55:24 pm
 :scared:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 09:16:43 pm
They use FWHH to measure peak shape.   I am using the 100/0 which I thought was very clear from all of the scope shots.  But then I have made statements about how it compares with 61010 so I can see how I clouded things up.   

Still it's not a big deal.  I'm starting to sound a bit like a broken record but again, I was not too concerned about what I hit the meters with, as long as they were all tested the same.  Again, I am not trying to certify the meters for CAT III.

I get that this was about comparing all the meters equally, and just seeing which was the toughest, and who ended up on top. I also get that your intent was never to "certify" that any of these meters actually meet IEC standards.

As for the waveform, I got by your earlier posts that the time you were talking about was based off of 100/0.  I had never bother to check how the standard measured them, and really did not care that much. I had assumed that you were trying to match that, because you referred to it so often.  So, I really paid no attention to your pulses until you asked me for the waveform of my generator.  When I did look up those pulses, that is when I noticed that mine were a lot different than yours, and even wondered if my machine was off. That is why I went back to that standard you had posted earlier, and realized that mine were right on, and yours were a little off from the standard.  I was not trying to get you to make yours perfect, I was just pointing out that I finally noticed the difference.

But, looking at your latest picture, you have REALLY stepped up your pulse width.  With your first 12 kV pulse you posted earlier, I was thinking I know you won't damage the Fluke, because that was less energy than I was giving it. But, with this latest pulse, it looks like you might be able to do some damage.  Imagine putting that pulse on some of those Mastech meters that you took out with 2kV, and the narrower pulse??

Have you bothered to check what your short circuit current waveform is yet?  Just wondering how close you are on that?

I'm really impressed with what you built, and how fast you did it.  You have built quite a fun experiment, and it got me interested enough in all this to actually do testing on it myself.  Thanks for sparking my interest enough to get me involved in all this.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 09:46:15 pm
THANK YOU!!  You stepped up, bought your own Fluke 101 and ran the test!  This saved me a lot of time knowing how hard I would have to push things.

It makes more sense to just use FWHH anyway. 

Yea, I stepped things up after you said you could not damage it.   The little toy generator is not so much a toy anymore.  Wearing gloves now and working one handed.  Today is really my last ditched effort to damage the Fluke 101.     

Would really like to see some other brands run on it.  Not low cost ones like I tested but ones that people just assume are good because they cost so much.    Not thinking there are too many that would want to play this game.   For those meters, it may be best to just stay with the drop and bucket tests.   :-DD 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 03, 2015, 10:01:17 pm
Guessing that was a custom unit for Fluke.     

Found what looks to be that model on-line.  The specs say it can go to 33 kV, and deliver 30 kA.  I don't even want to know what a machine like that costs.

So I could just order two of them?   :-DD

I think the 30A 8KV system we looked at last was around $80.   The 16A 2-phase 8KV system I am looking at now is around $30.   For non-certified, home project stuff, what I have is fine.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 03, 2015, 10:36:05 pm
I think the 30A 8KV system we looked at last was around $80.   The 16A 2-phase 8KV system I am looking at now is around $30.   For non-certified, home project stuff, what I have is fine.

My company paid $34K for our unit.  I could have just bought yours for the price of that 28 you mentioned, and used the rest for a nice vacation.......
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 12:27:01 am
Would really like to see some other brands run on it.  Not low cost ones like I tested but ones that people just assume are good because they cost so much.    Not thinking there are too many that would want to play this game.   For those meters, it may be best to just stay with the drop and bucket tests.   :-DD

I would really like to send you a Brymen BM829s, but it will cost me $80 to send it, plus the cost of the meter. It would be cheaper for me to build a pulse tester myself. I have around 10,000amps available at 48V with an impedance of around 0.1 ohm or less, and a neon transformer. The two don't work together but I would, like to build something that will do the job. The problem is that here in Chile it is hard to get anything, and loooooon time to get anything into the country.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 04, 2015, 01:36:18 am
Would really like to see some other brands run on it.  Not low cost ones like I tested but ones that people just assume are good because they cost so much.    Not thinking there are too many that would want to play this game.   For those meters, it may be best to just stay with the drop and bucket tests.   :-DD

I would really like to send you a Brymen BM829s, but it will cost me $80 to send it, plus the cost of the meter. It would be cheaper for me to build a pulse tester myself. I have around 10,000amps available at 48V with an impedance of around 0.1 ohm or less, and a neon transformer. The two don't work together but I would, like to build something that will do the job. The problem is that here in Chile it is hard to get anything, and loooooon time to get anything into the country.

I tried to see if it was available through Amazon.  Is it possible there are rebranded versions that you know would be identical?

Please don't let my small test box fool you.   It may seem like I did all this testing so fast that what I have shown is trivial.  There was a lot of time invested, not to mention the cost and dangers involved.    This isn't your little insulation tester.  If you make a mistake, you may end up paying the ultimate price!   There is a reason I have not disclosed any information about how it is built.   I don't want unskilled people to play with this stuff thinking that there is no risks involved! 
 
I would also like to point out that with the lack of standards on how to test them, using the IEC 61010 surge may not be the right way to evaluate them.   Making a tester that is not calibrated to a NIST standard may not give your customers confidence in the data you take.   

I would really like to see more electrical testing in reviews and would like to see something like this but I am just not sure this is the right answer. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 04, 2015, 01:52:49 am
I have around 10,000 amps available at 48V with an impedance of around 0.1 ohm or less, and a neon transformer. The two don't work together but I would, like to build something that will do the job.

48V at 10,000 Amps for what length of time??  Do you just have a large capacitor bank that you are charging, and then discharging.  What do you use that for??
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 02:07:49 am
I would really like to send you a Brymen BM829s, but it will cost me $80 to send it, plus the cost of the meter. It would be cheaper for me to build a pulse tester myself. I have around 10,000amps available at 48V with an impedance of around 0.1 ohm or less, and a neon transformer. The two don't work together but I would, like to build something that will do the job. The problem is that here in Chile it is hard to get anything, and loooooon time to get anything into the country.

I tried to see if it was available through Amazon.  Is it possible there are rebranded versions that you know would be identical?

Greenelee has the DM830A:
http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a (http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a)
Which is the BM829 re-branded. The price right now is much higher than the BM829S.

http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a (http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a)

Please don't let my small test box fool you.   It may seem like I did all this testing so fast that what I have shown is trivial.  There was a lot of time invested, not to mention the cost and dangers involved.    This isn't your little insulation tester.  If you make a mistake, you may end up paying the ultimate price!   There is a reason I have not disclosed any information about how it is built.   I don't want unskilled people to play with this stuff thinking that there is no risks involved! 
 
I would also like to point out that with the lack of standards on how to test them, using the IEC 61010 surge may not be the right way to evaluate them.   Making a tester that is not calibrated to a NIST standard may not give your customers confidence in the data you take.   

I would really like to see more electrical testing in reviews and would like to see something like this but I am just not sure this is the right answer.

Believe me, I am very familiar with high voltage with some good current behind it. I was the engineering manager for a scientific equipment company. I designed, helped build, and commissioned equipment that had 10kV 1A DC 100% duty cycle power supplies, 5kW RF power, and both combined. They also had electron beam gun heated crucibles that had 1-5kv bias on 200amp current for the filaments. I also had to build and certify the equipment to CSA special installation requirements.

I understand fully what kind of circuitry you have on those boxes, just not the details.

All a insulation breakdown tester will show is when arc over will occur, but no necessarily damage the item under test.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 02:16:16 am
I have around 10,000 amps available at 48V with an impedance of around 0.1 ohm or less, and a neon transformer. The two don't work together but I would, like to build something that will do the job.

48V at 10,000 Amps for what length of time??  Do you just have a large capacitor bank that you are charging, and then discharging.  What do you use that for??

Oh for probably something like 10 seconds. I have a bank of 8x 250Ah AGM batteries wired in 4 serial by 2 parallel. They have a new internal resistance of around 4 milliohm. So actually I would only get around 5000A. I forgot that I had to remove a third string when two batteries went bad.

I do have access to 3 banks of 4x4 of the same batteries, so yes I could easily get 10000A for 10 seconds at least.

They are for solar power storage.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 04, 2015, 04:13:10 am
Video showing the last couple of days including today running the 101 with that 13KV 100us FWHH 2 ohm setup, 3 hits both +/-.     

https://www.youtube.com/watch?v=DBBdhyzGk00&feature=youtu.be (https://www.youtube.com/watch?v=DBBdhyzGk00&feature=youtu.be)


Quote
Believe me, I am very familiar with high voltage with some good current behind it. I was the engineering manager for a scientific equipment company. I designed, helped build, and commissioned equipment that had 10kV 1A DC 100% duty cycle power supplies, 5kW RF power, and both combined. They also had electron beam gun heated crucibles that had 1-5kv bias on 200amp current for the filaments. I also had to build and certify the equipment to CSA special installation requirements.

I understand fully what kind of circuitry you have on those boxes, just not the details.

This should be a walk in the park for you then.    I look forward to seeing your setup.

Quote
Greenelee has the DM830A:
http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a (http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a)
Which is the BM829 re-branded. The price right now is much higher than the BM829S.

http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a (http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a)

I checked the links.  It's a bit too high priced for me just to run it against the Fluke 101.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 04:36:54 am
Quote
Believe me, I am very familiar with high voltage with some good current behind it. I was the engineering manager for a scientific equipment company. I designed, helped build, and commissioned equipment that had 10kV 1A DC 100% duty cycle power supplies, 5kW RF power, and both combined. They also had electron beam gun heated crucibles that had 1-5kv bias on 200amp current for the filaments. I also had to build and certify the equipment to CSA special installation requirements.

I understand fully what kind of circuitry you have on those boxes, just not the details.

This should be a walk in the park for you then.    I look forward to seeing your setup.

I really want to build something with some bite to it, the problem is getting the parts in Chile like I said. I will try, but I have so many other things to do.

Quote
Greenelee has the DM830A:
http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a (http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a)
Which is the BM829 re-branded. The price right now is much higher than the BM829S.

http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a (http://www.amazon.com/Greenlee-DM-830A-Digital-Multimeter-1000/dp/B003TO5YUU/ref=sr_1_1?ie=UTF8&qid=1435975207&sr=8-1&keywords=greenlee+dm-830a)

I checked the links.  It's a bit too high priced for me just to run it against the Fluke 101.

Yes I understand not wanting to throw money every which direction.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 04, 2015, 11:12:10 am
Happy 4th of July!!!!!

It seems like a good day to blow stuff up with a homemade surge generator....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 04, 2015, 03:32:43 pm
So, now that this testing is complete, what's next?

As discussed earlier in this thread, the possibility of most meters ever seeing a surge like this is very slim. It was very fun to see how the meters performed, even though they will seldom have to.

BUT, what is VERY likely to occur very often is users applying voltage to inputs that they should not (resistance, capacitance, amps, etc). The videos you see most often from Fluke and MG are meters catching fire from this mismatch.  2nd Edition of the standard allowed manufacturers to say what the input was protected to (like 240V on resistance, even though the meter can measure to 600V). 3rd Edition now requires the meter can not be a hazard if the full voltage gets put on any input. Since this is WAY more likely to happen, I wonder how many low end meters would survive this?

Do any of you guys have transformers that can deliver 600 to 1000V with some decent current behind it?  My 1000V transformer can only supply 500mA, and that is not enough energy for this testing. Maybe this would be easier to test with DC? Lightages could charge those batteries up to 1000V, and see how long meters could survive that with some decent current behind the voltage?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 04, 2015, 04:52:59 pm
Happy 4th of July!!!!!

It seems like a good day to blow stuff up with a homemade surge generator....

 :-+   Happy Independence Day!    As they were importing tea from China, now we import the Fluke 101 from China.  Although I saw a video where someone took it apart and they suspect that at least the board was made in India,  where the tea also came from.   Maybe I'll throw the thing into the harbor and see if that damages it!   :-DD

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 05:33:09 pm
Do any of you guys have transformers that can deliver 600 to 1000V with some decent current behind it?  My 1000V transformer can only supply 500mA, and that is not enough energy for this testing. Maybe this would be easier to test with DC? Lightages could charge those batteries up to 1000V, and see how long meters could survive that with some decent current behind the voltage?

The best I can do right now is high current or high voltage. I can't do both. I do have a big variac and some transformers I can play with along with a neon tranformer. I will see what I can do after I get caught up on some other things. If you don't hear from me again, I probably touched the wrong part of the circuit whilst experimenting. :scared: (don't worry, it won't happen)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 04, 2015, 06:31:17 pm
So, now that this testing is complete, what's next?

BUT, what is VERY likely to occur very often is users applying voltage to inputs that they should not (resistance, capacitance, amps, etc). The videos you see most often from Fluke and MG are meters catching fire from this mismatch.  2nd Edition of the standard allowed manufacturers to say what the input was protected to (like 240V on resistance, even though the meter can measure to 600V). 3rd Edition now requires the meter can not be a hazard if the full voltage gets put on any input. Since this is WAY more likely to happen, I wonder how many low end meters would survive this?

I thought this was covered in 4.4.2.101 and 101.   

Dave does a good job checking this on at least on some of the meters he reviews.  He plugs them into the outlet (220) and runs them through their paces.     

https://www.youtube.com/watch?feature=player_detailpage&v=bKvyoZa5J8Q#t=1968
 (https://www.youtube.com/watch?feature=player_detailpage&v=bKvyoZa5J8Q#t=1968)

If we are talking real world, do you want to go higher than this?    I think I could put something together fairly quickly if you want.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 06:42:46 pm
I can apply 1000V to each of the ranges, and even 5000V. It would only be with a few milliamps though. This did damage the UT61E but it does not demonstrate that the meter does not harm the user with these conditions. That would require something more like 1000V at 10 or 15 amps (or more) as would be available on a circuit of that type.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 04, 2015, 09:45:58 pm
But is a 1000 or 5000 at several amps very likely?   I can't answer that. 

I took a 1000uF, charged it to 440V, using a large solenoid and some 16AWG test leads I made for this test, spanked the 101 with it while in resistance, diode and continuity.    There are two time constants.  It decays rather rapidly to 240 volts, then just hangs out around there until I cut the power.   

This seems to have no affect on the 101, but I assumed from the 61010 standard, it wouldn't.   Here is a short video recorded at normal speed which provides some idea of the time constant.   

https://www.youtube.com/watch?v=X_7uIOD_qPA (https://www.youtube.com/watch?v=X_7uIOD_qPA)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 04, 2015, 10:54:28 pm
But is a 1000 or 5000 at several amps very likely?   I can't answer that. 

No, not very likely, but possible in some power supplies that I have worked on in the past, at least 1000V at 1A and higher. If  meter is rate at CATIII/1000V, then it better handle more than a couple of milliamps at 1000V on all functions and all input jacks. I still do not have the full IEC specifications for the tests, but the parts I do have do not indicate the current availability for this kind of test, at least I am not sure. I have one clause that states:

Quote
16.2 Multifunction meters and similar equipment
Multifunction meters and similar equipment shall not cause a HAZARD in any possible combination
of RATED input voltages, and settings of function and range controls. Possible HAZARDS include
electric shock, fire, arcing and explosion.
Conformity is checked by the following test.The maximum RATED voltage specified for any function is applied to each pair of TERMINALS in
turn, in every combination of function and range controls. The test source connected to the
equipment measuring TERMINALS during this test is limited to 3.6 kVA for measurement category I
or measurement category II. For measurement category III or measurement category IV, the test
circuit has to be capable of delivering 30 kVA.

During and after the tests, no HAZARD shall arise.
Multifunction meters and similar equipment are to be tested by changing the Function/Range Selector to all
possible settings while connected to the maximum rated source.

So based on this, I guess, that a meter rated at 1000V maximum input must be able to not cause harm with a source of 3.6A if CATI or CATII, and 30A if CATIII or CATIV. So an insulation tester capable of a few milliamps will not give you any real indication of the ability of the meter to pass this part of the test. If it fails at a few milliamps, that just mean it failed to operate after. It is very hard to cause harm to the user with a few milliamps contained in the meter housing.

I have another clause from somewhere that states:

Quote
101.4  Functional  integrity
After the voltage of  4.4.2.101  has  been applied to the  METER, the  METER  shall continue to be
able to indicate the presence of HAZARDOUS  LIVE  voltages up to the maximum RATED  voltage.

I do not know what the voltage required in 4.4.2.101 is, so I am shooting in the dark. Like I said before, it is ridiculous that a safety standard for the public, made by public funds, is hidden for payment.

Edit:

I should also say the fee is beyond reasonable. $340 for just the general part? So  much for trying to protect the public. It is just a big cash grab, just like lawyers and accountants.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 05, 2015, 12:45:47 am
I thought this was covered in 4.4.2.101 and 101.   

Dave does a good job checking this on at least on some of the meters he reviews.  He plugs them into the outlet (220) and runs them through their paces.     

https://www.youtube.com/watch?feature=player_detailpage&v=bKvyoZa5J8Q#t=1968
 (https://www.youtube.com/watch?feature=player_detailpage&v=bKvyoZa5J8Q#t=1968)

If we are talking real world, do you want to go higher than this?    I think I could put something together fairly quickly if you want.   

4.4.2.101 covers just the mains terminal, and it states that the MAINS must handle 1.9 times the rated voltage for the unit up to 900 and something for a 600 V meter, and up to 1100 V for a 1000V rated meter. Then, 101 covers handling the voltage on other inputs that are not expecting that voltage.  But, like I said, this is for 3rd Edition, and companies don't need to be supplying these until 2018.  The majority of the meters out there today are to 2nd Edition, and handling the full voltage is not required.

Yes, I know Dave puts 220 on to some meters he checks, but that is like some of the meters you tested surviving a 2,000V surge, when it could see as high as 6,000.  Look at the specifications for some of those cheap meters that were out early in your testing (I'm sure you still have the manuals laying around).. I would bet that if you look at the overload protection on some of those functions they are around 250V.  So, these could probably (if they really meet that spec) pass 250V, but could turn to a fire bomb at 480V, or the 600V the meter is rated for.

Now, would I use a $50 Mastech meter when measuring 480 or 600??  Heck NO!!   But, there are users that would, and they may not be safe if they had the meter set wrong.

As for the currents that could be available real world, you know that any AC line you are on could deliver greater than 30 Amps if presented by a dead short in the meter, after something fails due to the over voltage. Finding a DC system with that current behind it would be much harder, and would be something like a third rail on a train.  I wasn't saying that finding a DC high voltage application with current behind it would be common. I was saying it would be easier to have a DC test jig.

For us to get access to 600V with 30A of current behind it would be unlikely (and extremely dangerous). Even if we had a 240 to 600 step up transformer, you would need 80 Amps on the primary to get that current for testing.  With DC for testing, we could use batteries, or charge big enough caps to keep that power sustained for a while. For small caps they would create more of a "surge" that the front end could handle for a few milliseconds.  But, would they blow with more power behind it for a while??

I'm assuming they would, but I don't have access to AC with that power.  I've looked a caps to charge, but a 1300V 480uF cap runs around $200 (with my quick search), and you would need a lot of those to sustain this for a while. 

This seems harder to test, but a more likely failure that can happen.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 05, 2015, 12:51:04 am
I can apply 1000V to each of the ranges, and even 5000V. It would only be with a few milliamps though. This did damage the UT61E but it does not demonstrate that the meter does not harm the user with these conditions. That would require something more like 1000V at 10 or 15 amps (or more) as would be available on a circuit of that type.

Yeah, milliamps (like your Megger) won't show how bad a meter would be damaged.  I can get to 3000V with 500mA behind it, but I'm not sure even that would give enough power to wipe out meters like Fluke does to the Harbor Freight meters in all their videos.  Maybe I should just pick another one up to see. The last 2 I bought had the voltage jack fused, so maybe they changed the design.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 05, 2015, 02:18:15 am
Quote
I should also say the fee is beyond reasonable. $340 for just the general part? So  much for trying to protect the public. It is just a big cash grab, just like lawyers and accountants.
:-+

Quote
4.4.2.101 covers just the mains terminal
101 refers to 4.4.2.101.   Mismatch of leads is covered in 101.3. 

Quote
16.2 Multifunction meters and similar equipment
I would think this would be the limit of 4.4.2.101 as well but I am not sure. 

Again, I can see how come I get different answers from the companies who make the meters.  Someone at TUV needs to write the the IEC61010 guide for dummies!    I would buy it!  But I bet all we would see inside is how it is up to the companies themselves to determine the risks.

Quote
Yes, I know Dave puts 220 on to some meters he checks, but that is like some of the meters you tested surviving a 2,000V surge, when it could see as high as 6,000.

Sorry but I am not getting your point.   These are two separate tests.  Two separate goals.   Again, my goal was to determine which meters were more robust than others.  I did this by increasing the energy supplied to all the meters and seeing at what point they failed.  Again, this has nothing to do with safety or meeting the IEC standards.     What Dave is doing (IMO) is more real world common testing.  I have done just what he is testing to countless times.     

You like using that four letter word "safe" but if the goal is to determine something about safety, I can't help.   That's best to leave with the TUVs, CASs and ULs of the world! 

Quote
I can get to 3000V with 500mA behind it,

Is 3000V at 500mA a common thing people measure with their handhelds?   If your goal is only to damage them, I can pop the back covers off and I'll hang it on that neon sign transformer.   Seems I have seen that sort of thing happen before!   :-DD :-DD

If the goal is just to see if meters can survive common faults, I think we need to define what that is.   We could turn to IEC, but all they have is "REASONABLY FORESEEABLE MISUSE".    :-DD

If you can think of a test that is something that you feel is a common problem for the average handheld user, post about it.   

My first Fluke died twice.  Once from me measuring a HV supply that was near what the meter was rated for and I assumed it could handle it.   That was the first $70.    Later the meter was hit with a little back EMF and again died.   The HPs I now have have never failed.   I bought them both new.  The oldest must be more than 20 years old now.      The last two handhelds you saw.  The LCD was cracked after I dropped the one.  The other HF one had a mechanical failure with the LCD.   Then there's the BK that I think the switch just wore out on.   I really have not seen a lot of failures during my life.   I did see a guy hook a thermocouple input to the AC mains once that damaged a meter but even that is the only thing that comes to mind.   

I can see things like someone wanting to check their car ignition system and hooking it to the output of one of the coils.  For that matter, even on the primary side.    Or hooking it across something like a large starter solenoid or a fuel shut off valve with no flyback protection.     As mentioned earlier, many transients don't come from the line.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 05, 2015, 03:47:31 am
Sorry but I am not getting your point.   These are two separate tests.  Two separate goals.   Again, my goal was to determine which meters were more robust than others.  I did this by increasing the energy supplied to all the meters and seeing at what point they failed.  Again, this has nothing to do with safety or meeting the IEC standards.     What Dave is doing (IMO) is more real world common testing.  I have done just what he is testing to countless times. 

My point was that it would be pretty easy to protect the resistance input from 50V, or 220V, but not so easy to protect it from 1000V.  Just like it may be easy to protect the meters you tested from 2000V through 50 ohms, but not so easy from 13kV through 2 ohms. You wanted to see how much abuse they could take from surges, and I'm wondering how well they would hold up from a mis-match.

 
Quote
Is 3000V at 500mA a common thing people measure with their handhelds?   If your goal is only to damage them, I can pop the back covers off and I'll hang it on that neon sign transformer.   Seems I have seen that sort of thing happen before!   :-DD :-DD

If the goal is just to see if meters can survive common faults, I think we need to define what that is.   We could turn to IEC, but all they have is "REASONABLY FORESEEABLE MISUSE".    :-DD

If you can think of a test that is something that you feel is a common problem for the average handheld user, post about it.
 

I wasn't saying a meter commonly sees 3000V at 500mA. I'm not just trying to damage meters. I could come up with many ways to damage meters is that is what I was looking for.  I was saying that is all I have to work with, and that won't let me test these the way I would like.  I would like to see how they can handle 480V, 600V, or 1000V, on any input.  With that supply I was mentioning, I could give them the voltage, but the limited current would not simulate what would really happen if someone put a meter across 480V that had the potential to supply 30 Amps.  I've seen a dozen low end ($5 Harbor Freight) meters blown up on videos with that fault. I'm curious how $50 or $100 meters would do. I also know spikes can come from many sources other than a lightning strike. But, I'm also pretty sure there are a lot more meters plugged into high voltage on continuity or Amps, than seeing spikes.

Again, I'm not saying that you were testing these meters to meet IEC for spikes, and I want to test them to meet IEC for voltage on a jack that shouldn't be there.  I'm just curious what meters could handle that, and which couldn't. But, I don't have a way to test it, and I was hoping others did.  If not, and I want to see it, I'll have to look at building it myself (when I have the time, money, and enough desire).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 05, 2015, 04:04:32 am

Quote
4.4.2.101 covers just the mains terminal
101 refers to 4.4.2.101.   Mismatch of leads is covered in 101.3. 

Attached is 4.4.2.101 which covers the Voltage levels to the MAINS.  Yes, I know mismatch was specific to 101.3.  I was just saying that was in section 101, and not saying the specific section.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 05, 2015, 04:03:08 pm
To be clear then,  you would like to test them to the 4.4.2.101?   

If you just want to see how the meters hold up electrically,  you may not need the full 30A.   I have an 600Vish 350W supply sitting here from an old radio.   I could see someone who is attempting to work on old systems like this, hooking their meter to it.   It has not been turned on in many years.  Let me blow the dust off and see how the 101 likes it. 

Almost forgot, that will be 60Hz AC average voltage.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 05, 2015, 10:01:44 pm
To be clear then,  you would like to test them to the 4.4.2.101?   

To be clear, I don't want them tested to ANY standard.  You, more than anybody, should get what I'm saying.

When you started this whole thread, you wanted to determine how "robust" under $50 meters were.  To determine this you decided to see how well they could handle high voltage surges.  You referenced the surges required to meet CAT ratings, and built a generator loosely based off this standard.  You were not testing that they met the IEC standards, or trying to prove if any did not meet standards, you just wanted to see which meters held up to these surges the best, and that would determine which was more robust.

I also would like to see how robust meters are, but with another type of test.  Instead of how robust they are in surges, I would like to see how robust they are in handling a voltage on a position that is not expecting a voltage (like resistance, or capacitance).  I don't want to test them to a standard, but section 101.3 of 61010-2-033  (attached at the end) would serve as a decent test to base the testing off of. This section talks of putting the highest voltage the meter can test on the mains, on putting that on every jack, and every switch position.  It does not require the meter to survive, just not become a hazard.  So, for a robustness test, it would be interesting to see which meters can survive the highest voltages on these various switch positions. None of the meters should go much beyond the voltage they measure to.  I would expect that the PTC's and MOV's are set to clamp just above that level.  Once you get above that, it is just a matter of how long before those protection devices can't handle that voltage. I'm not trying to prove if any meter meet the attached standard, I'm just curious which ones could survive the longest.  I'm also not interested in testing this for the current jacks, just the functions that would work off the same jack as the voltage, but in the wrong switch position.

What voltage would meters see on these positions, and what is reasonable??  I don't know, and I don't care.  It's not about how high of a voltage is reasonable on that jack, just how you kept taking the surge as high as you could, until you could get a failure.  But, I do know a lot of inexperienced people put meters on high voltages without knowing it.  I had a friend that damaged a cheap meter because he tried to measure the voltage coming out of a dog shock collar, and that was on the voltage position. 

I would expect a unit like the Fluke 101 to be able to take the full 600V on all levels.  I don't know how far beyond 600V it would go, but I'll bet it would go farther than any of the units you tested for the surge.  I would bet the Mastech unit would fail not too far past 300V.  Look at the link for the spec sheet of the Mastech 8261 you tested.  It lists the maximum voltage on the mV position as 250V, and protection on other positions like resistance as 380V.  This would not be a "more robust" meter.

http://www.p-mastech.com/images/Manual/ms8261%20english%20manual.pdf (http://www.p-mastech.com/images/Manual/ms8261%20english%20manual.pdf)


I'm also not asking YOU to test this.  I was saying this wold be something I would like to see.  If nobody else does testing like this, I just may have to do it myself.  I'm sure that I can get enough power out of my transformer to damage the meter, and determine how robust it is for handling the voltage.  What I may not be able to determine id "how bad" the damage "could have" been.  Once a meter fails due to high voltage on the wrong input, it could become shorted inside, draw lot of current, and fail violently.  My transformer would not be able to show that.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 05, 2015, 10:41:14 pm
Quote
To be clear, I don't want them tested to ANY standard.  You, more than anybody, should get what I'm saying.
Never assume I understand anything.   :-DD :-DD

Quote
I don't want to test them to a standard, but section 101.3 of 61010-2-033  (attached at the end) would serve as a decent test to base the testing off of.

 :-+

Quote
I don't want to test them to a standard, but section 101.3 of 61010-2-033  (attached at the end) would serve as a decent test to base the testing off of. This section talks of putting the highest voltage the meter can test on the mains, on putting that on every jack, and every switch position.  It does not require the meter to survive, just not become a hazard.

You did not include everything.  The way I understand it, the DUT must survive.  But again, I bet we would get different answers from the manufactures as well.  No big deal.  See below...

Quote
101.3.1 General
Conformity is checked by inspection, evaluation of the design of the equipment, and as
specified in 101.3.2 to 101.3.3, as applicable.

101.3.2 Protection by a certified overcurrent protection device

During and after the test, no damage to the equipment shall occur.

101.3.3 Protection by uncertified current limitation devices or by impedances

During and after the test, no HAZARD shall arise, nor shall there be any evidence of fire,
arcing, explosion, or damage to impedance limitation devices or any component intended to
provide protection against electric shock, heat, arc or fire, including the ENCLOSURE and traces
on the printed wiring board.

No matter how this meter is protected (I am treating it as a black box) it needs to survive the test IMO.

That aside...   Watch the following as I amp up the 440V capacitor dump test....

Quote
https://www.youtube.com/watch?v=QEMCrGchLxs&feature=youtu.be
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 05, 2015, 10:58:39 pm
So the way I read the specs that I have seen, in the end:

1. All terminals must withstand the rated voltage of the highest voltage stated on the meter, in every position of the function switches.

2. If there are any current limiting devices, they must function without any outward sign of them function or failing in any way, and must not be damaged or incur damage to the meter.

3. After the tests have been run, surge and cross function testing, the specs imply but do not state explicitly, that the meter should function well enough to show the highest rated voltage on the voltage function.

4. The specs do not imply that the meter must function properly on all functions after the test, just that it must show a proper voltage reading on the voltage functions after being subjected to the tests.

5. The tests should be done with the included test leads as they are part of the impedance path.

6. In all cases, the user must not be exposed to any harm as result of the test voltages and currents being applied.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 05, 2015, 11:03:35 pm
Well, the specs say what they say.   I guess you could interpret them this way.   I would say for the part we are now looking at,  101.3.4 comes into play:

101.3.4 Test leads for the tests of 101.3.2 and 101.3.3

Sure you state that
Quote
5. The tests should be done with the included test leads as they are part of the impedance path.
But that's not what I see at all.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 12:53:25 am
What camera are you using for your videos?  It does a very nice job.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 06, 2015, 01:00:41 am
What I was referring to is this part that I have gleaned from other posts. Remember that I am only going on the parts that I have seen and they might be out of context.

Quote
16.2 Multifunction meters and similar equipment
Multifunction meters and similar equipment shall not cause a HAZARD in any possible combination
of RATED input voltages, and settings of function and range controls. Possible HAZARDS include
electric shock, fire, arcing and explosion.
Conformity is checked by the following test.The maximum RATED voltage specified for any function is applied to each pair of TERMINALS in
turn, in every combination of function and range controls. The test source connected to the
equipment measuring TERMINALS during this test is limited to 3.6 kVA for measurement category I
or measurement category II. For measurement category III or measurement category IV, the test
circuit has to be capable of delivering 30 kVA.

During and after the tests, no HAZARD shall arise.
Multifunction meters and similar equipment are to be tested by changing the Function/Range Selector to all
possible settings while connected to the maximum rated source.”
NOTE If test probes are provided with the equipment being tested then they are to be used for the test.
Compliance is checked by testing to verify no hazard occurs when switching selector settings.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 01:12:00 am
What I was referring to is this part that I have gleaned from other posts. Remember that I am only going on the parts that I have seen and they might be out of context.

Quote
16.2 Multifunction meters and similar equipment
Multifunction meters and similar equipment shall not cause a HAZARD in any possible combination
of RATED input voltages, and settings of function and range controls. Possible HAZARDS include
electric shock, fire, arcing and explosion.
Conformity is checked by the following test.The maximum RATED voltage specified for any function is applied to each pair of TERMINALS in
turn, in every combination of function and range controls. The test source connected to the
equipment measuring TERMINALS during this test is limited to 3.6 kVA for measurement category I
or measurement category II. For measurement category III or measurement category IV, the test
circuit has to be capable of delivering 30 kVA.

During and after the tests, no HAZARD shall arise.
Multifunction meters and similar equipment are to be tested by changing the Function/Range Selector to all
possible settings while connected to the maximum rated source.”
NOTE If test probes are provided with the equipment being tested then they are to be used for the test.
Compliance is checked by testing to verify no hazard occurs when switching selector settings.

I agree with you, and believe it does not have to function, just not become a hazard. However, that 16.2 section that you are posting is from 61010-1 2nd Edition.  It is not in 3rd Edition.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 06, 2015, 01:17:49 am
Does the 3rd edition and the supplements say anything about the need to use the test leads as supplied for the tests?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 02:07:13 am
Quote
To be clear, I don't want them tested to ANY standard.  You, more than anybody, should get what I'm saying.
Never assume I understand anything.   :-DD :-DD

Quote
I don't want to test them to a standard, but section 101.3 of 61010-2-033  (attached at the end) would serve as a decent test to base the testing off of.

 :-+

Quote
I don't want to test them to a standard, but section 101.3 of 61010-2-033  (attached at the end) would serve as a decent test to base the testing off of. This section talks of putting the highest voltage the meter can test on the mains, on putting that on every jack, and every switch position.  It does not require the meter to survive, just not become a hazard.

You did not include everything.  The way I understand it, the DUT must survive.  But again, I bet we would get different answers from the manufactures as well.  No big deal.  See below...

Quote
101.3.1 General
Conformity is checked by inspection, evaluation of the design of the equipment, and as
specified in 101.3.2 to 101.3.3, as applicable.

101.3.2 Protection by a certified overcurrent protection device

During and after the test, no damage to the equipment shall occur.

101.3.3 Protection by uncertified current limitation devices or by impedances

During and after the test, no HAZARD shall arise, nor shall there be any evidence of fire,
arcing, explosion, or damage to impedance limitation devices or any component intended to
provide protection against electric shock, heat, arc or fire, including the ENCLOSURE and traces
on the printed wiring board.

No matter how this meter is protected (I am treating it as a black box) it needs to survive the test IMO.

That aside...   Watch the following as I amp up the 440V capacitor dump test....

Quote
https://www.youtube.com/watch?v=QEMCrGchLxs&feature=youtu.be

You did not post all of 101.3.3, which is the section that we would be talking about, because these inputs are protected by PTC's and MOV's, and not fuses, which is what 101.3.2 seems to refer to.

Read all of 101.3.3.  It say the protection circuit could be damaged, but that it should not damage other parts of the unit. If that PTC is damaged, the unit will probably not be functional, but would not become a hazard. You stopped your post right at the VERY next key line that says "Any damage to a device used for current limitation shall be ignored".

I am attaching the rest of section 101.3.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 02:09:25 am
Does the 3rd edition and the supplements say anything about the need to use the test leads as supplied for the tests?

Yes, that is listed in the documents I posted above.  It states to use the supplied leads, and then to repeat the test with others leads described in the standard.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 06, 2015, 02:27:12 am
I am just using my old Cannon camera.   


Quote
You did not post all of 101.3.3, which is the section that we would be talking about, because these inputs are protected by PTC's and MOV's, and not fuses, which is what 101.3.2 seems to refer to.

It states "No part of this publication may be reproduced...".   I am not comfortable posting large sections.     

Quote
and not fuses, which is what 101.3.2 seems to refer to.
101.3.2 is for certified overcurrent protection device.   This can be more than fuses, or they would not state:
Quote
If the protection device is a fuse, ...
I believe this is any certified overcurrent device as it states.   This could be a PTC as long as it has been certified. 

101.3.3 is for uncertified current limitation devices.   This could be an uncertified fuse.  I saw a few of them.

We could debate the standards to no end.   There's really no point.    You see it one way, I see it another.  The manufactures don't agree.   No big deal.   One things for sure,  I would rather have a meter that remained functional than one that does not.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 06, 2015, 02:39:56 am
Quote
Read all of 101.3.3.  It say the protection circuit could be damaged, b

Quote
During and after the test, ... or damage to impedance limitation devices or any component intended to provide protection against electric shock,...

I have no idea where you would see this as allowing the protection circuit to be damaged.   :-//    It is interesting how many ways a poorly written standard can be interpreted. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 02:48:22 am
Quote
Read all of 101.3.3.  It say the protection circuit could be damaged, b

Quote
During and after the test, ... or damage to impedance limitation devices or any component intended to provide protection against electric shock,...

I have no idea where you would see this as allowing the protection circuit to be damaged.   :-//    It is interesting how many ways a poorly written standard can be interpreted.

What about the line that stated "Any damage to a device used for current limitation shall be ignored"?????
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 03:00:43 am
  :-//    It is interesting how many ways a poorly written standard can be interpreted.

Maybe they will finally make it clear by the 5th or 6th Edition......
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 06, 2015, 04:07:01 am
Quote
Read all of 101.3.3.  It say the protection circuit could be damaged, b

Quote
During and after the test, ... or damage to impedance limitation devices or any component intended to provide protection against electric shock,...

I have no idea where you would see this as allowing the protection circuit to be damaged.   :-//    It is interesting how many ways a poorly written standard can be interpreted.

What about the line that stated "Any damage to a device used for current limitation shall be ignored"?????

You only captured part of that sentence.  It states:
Quote
Any damage to a device used for current limitation shall be ignored if other parts of the equipment were not affected during the test.

Quote
If a device used for current limitation is damaged, it is replaced before the test is repeated.

In these two cases I believe they are referring to a user serviceable device.   UL, TUV and the like are not going to pull our their solder stations and start swapping parts.   I can see them changing a fuse.    So, if the fuse blew and no other damaged occurred, to the equipment, you can ignore that failure.   

Again, that's just the way I would read it.    If they made the standards clear, like I have to in my job, then companies could produce product which met these standards.  That would put a lot of government inspectors out of jobs and would allow a more fair global trade.   WTC is not tied with TUV for the fun of it.     If they made the standards that the people paid for, free for the people to read, the people may actually think,  :wtf: This is the safety standards we paid $$$$$ for you to come up with??   :-DD :-DD    If you have a TUV safety inspector you work with, ask them next time if some product you are working on is safe.  See what sort of response you get. 

All I can say is that the Fluke 101 can sit on the plate supply of the Drake TR-4 for at least 30 seconds in resistance, continuity, diode check and capacitance modes for at least 30 seconds and you can rotate the switch while the voltage is applied as much as you want.   If I had 10 more meters, I would have repeated that test on all of them.   I may have had 10 more dead meters too!  :-DD

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 06, 2015, 12:01:43 pm
If you have a TUV safety inspector you work with, ask them next time if some product you are working on is safe.  See what sort of response you get. 

I have never worked with TUV, only ETL and UL.

But, I have asked questions about standards on numerous occasions, trying to clear things up on standards. In areas where it did not seem clear, I ask specific questions about the meaning, and I have NEVER received a straight answer back. They will pretty much just do their testing, and tell you if you pass or fail. They never clarify the standard, probably because they don't know for sure either.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Neilm on July 06, 2015, 06:59:37 pm
But, I have asked questions about standards on numerous occasions, trying to clear things up on standards. In areas where it did not seem clear, I ask specific questions about the meaning, and I have NEVER received a straight answer back. They will pretty much just do their testing, and tell you if you pass or fail. They never clarify the standard, probably because they don't know for sure either.

The trouble is they can't say "if the fuse blows change it" as someone might have some other way of interrupting the current and they would not want to preclude that.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 07, 2015, 02:45:02 am
Looks like Hackaday picked up the story.   

http://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/ (http://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/)

I was fine with what they wrote until this part:

Quote
What’s the secret to Fluke’s success? You only need to look at what the Fluke 101 can’t do. Fluke’s budget meter doesn’t measure current. If you ever look inside a meter, you’ll usually find two fuses, one for measuring Amps and the other for all the other functions on the scope. There’s quite a bit of engineering that goes into the current measurement of a meter, and when it goes wrong you have a bomb on your hands. Fluke engineers rather intelligently dropped current measurement from this budget meter, allowing them to save that much on their BOM.

Which appears to have led to more confusion.   If people would have watched the videos, they would have known that no meter from the CAT III group was damaged in current mode.   They would also know that I stopped testing the current mode early on because the generator was putting out enough to blow the fuses and I did not want to replace them.   So all the meters were only tested using the modes that used the voltage input connections.   They would also have noticed that the Klein Tools meter had even less features than the 101 and was beat out by even the AMPROBE that has far more features.   The Gardner Bender meter failed in the first round of tests and where is it's current sense feature?

We can only run the tests, collect the data and post the results.    If people want to slant the data, I can't fix that.   

So, why does the 101 hold up so well?   I suspect circuit design, layout and part selection.   I have not taken this 101 apart but there is a video on youtube that shows the board.  Talk about an air gap.     But ... as much as it kills me to say it,  even more than the design, I suspect the culture within the company demands the meters meet a very high level of standards.    Again, some companies I contacted felt it was fine for a meter to not be functional after the surge test, while others require their products are not damaged.     The real test is going to be to get a high end meter and run it through the same tests.  That meter is going to have a lot more features than the 101.   

I gave up on contacting the service groups at the main companies.   If if blows I'll just return the thing and hope they warranty it.    Now if I could just find a meter I like.... 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on July 07, 2015, 02:53:13 am
Quote
Now if I could just find a meter I like....

:-+
But I'm getting low on   :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 07, 2015, 03:49:54 am
I think it will be hard to get ANY company to send a meter to anyone who's intention is to try and make it blow up. Even if they are 100% confident that it meets all safety standards and quality. The tests will be continued until failure and no company wants to help show its product failing, reasonably or not.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 07, 2015, 12:17:22 pm
I think it will be hard to get ANY company to send a meter to anyone who's intention is to try and make it blow up. Even if they are 100% confident that it meets all safety standards and quality. The tests will be continued until failure and no company wants to help show its product failing, reasonably or not.

Getting a meter in the USA is not difficult.  You place the order, they send you the meter.   They don't ask the intended use when an order is placed. 
To be clear, I have NEVER asked Fluke or Keysight to send me a meter.    What I have asked them is if they would warranty their products if they failed before the Fluke 101.  I also provided them the link to this forum.  Only one company responded (not Fluke or Keysight).   

Also, as I mentioned earlier, I don't think there is much more I can do to test the meters at home.  My plan now is to just run the higher end meter through the tests that the 101 has been through and see if it survives. 

Because I plan to keep the higher end meter, there are certain features I would like to have.    I would have bought the Keysight already but to be honest, their lack of response does not give me a lot of confidence in them.      If I could combine the higher count and AC+DC mode with the 28II, I would have bought it.       
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Meter Junkie on July 07, 2015, 02:33:50 pm
To be clear, I have NEVER asked Fluke or Keysight to send me a meter.    What I have asked them is if they would warranty their products if they failed before the Fluke 101.  I also provided them the link to this forum.  Only one company responded (not Fluke or Keysight).   

How are you contacting these companies? By sending an email to customer service from the website? A typical customer service person wouldn't have a clue what you are talking about, and be able to respond to you.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on July 07, 2015, 04:16:36 pm
To be clear, I have NEVER asked Fluke or Keysight to send me a meter.    What I have asked them is if they would warranty their products if they failed before the Fluke 101.  I also provided them the link to this forum.  Only one company responded (not Fluke or Keysight).   

How are you contacting these companies? By sending an email to customer service from the website? A typical customer service person wouldn't have a clue what you are talking about, and be able to respond to you.

I work in Biotech and our CS reps are trained to escalate with technical questions to the TS team. If the TS team doesn't know they forward it on to the scientists. I would imagine this is the same for them.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 07, 2015, 05:09:32 pm
Do we pull the trigger???  After all it should at least be as robust as the 101, right?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on July 07, 2015, 05:25:56 pm
I concur.  Luckily, eevblog is well indexed by google and appears first when a search is done on a topic discussed here.  Eevblog has more informed members that generate less noise compared to hackaday.

In toto this thread suggests Fluke's low end meters sacrifice feature sets, but maintain safety expected of its more expensive DMMs.  Following the videos as they evolved in the series, its clear to me showcasing Fluke was not the goal, it just happened this way, even if not so, so long as the surge energies be true, the meter has survived, QED.

Electricians often use clamp meters to measure current, so such users can opt to have just what they need and avoid the potential pitfalls that blow expensive DMM fuses.


Looks like Hackaday picked up the story.   

http://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/ (http://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/)

I was fine with what they wrote until this part:

Quote
What’s the secret to Fluke’s success? You only need to look at what the Fluke 101 can’t do. Fluke’s budget meter doesn’t measure current. If you ever look inside a meter, you’ll usually find two fuses, one for measuring Amps and the other for all the other functions on the scope. There’s quite a bit of engineering that goes into the current measurement of a meter, and when it goes wrong you have a bomb on your hands. Fluke engineers rather intelligently dropped current measurement from this budget meter, allowing them to save that much on their BOM.

Which appears to have led to more confusion.  If people would have watched the videos, they would have known that no meter from the CAT III group was damaged in current mode.     

So, why does the 101 hold up so well?  I suspect circuit design, layout and part selection.   I have not taken this 101 apart but there is a video on youtube that shows the board.  Talk about an air gap.     But ... as much as it kills me to say it,  even more than the design, I suspect the culture within the company demands the meters meet a very high level of standards.    Again, some companies I contacted felt it was fine for a meter to not be functional after the surge test, while others require their products are not damaged.     The real test is going to be to get a high end meter and run it through the same tests.  That meter is going to have a lot more features than the 101.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 08, 2015, 12:53:40 am
Do we pull the trigger???  After all it should at least be as robust as the 101, right?
nice! I dunno man.. Grats on the 87V though!  :-DMM
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on July 08, 2015, 04:49:49 pm
Looks like Hackaday picked up the story.   

http://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/ (http://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/)

I was fine with what they wrote until this part:

Quote
What’s the secret to Fluke’s success? You only need to look at what the Fluke 101 can’t do. Fluke’s budget meter doesn’t measure current. If you ever look inside a meter, you’ll usually find two fuses, one for measuring Amps and the other for all the other functions on the scope. There’s quite a bit of engineering that goes into the current measurement of a meter, and when it goes wrong you have a bomb on your hands. Fluke engineers rather intelligently dropped current measurement from this budget meter, allowing them to save that much on their BOM.

Which appears to have led to more confusion.   If people would have watched the videos, they would have known that no meter from the CAT III group was damaged in current mode.   They would also know that I stopped testing the current mode early on because the generator was putting out enough to blow the fuses and I did not want to replace them.   So all the meters were only tested using the modes that used the voltage input connections.   They would also have noticed that the Klein Tools meter had even less features than the 101 and was beat out by even the AMPROBE that has far more features.   The Gardner Bender meter failed in the first round of tests and where is it's current sense feature?

We can only run the tests, collect the data and post the results.    If people want to slant the data, I can't fix that.   

So, why does the 101 hold up so well?   I suspect circuit design, layout and part selection.   I have not taken this 101 apart but there is a video on youtube that shows the board.  Talk about an air gap.     But ... as much as it kills me to say it,  even more than the design, I suspect the culture within the company demands the meters meet a very high level of standards.    Again, some companies I contacted felt it was fine for a meter to not be functional after the surge test, while others require their products are not damaged.     The real test is going to be to get a high end meter and run it through the same tests.  That meter is going to have a lot more features than the 101.   

I gave up on contacting the service groups at the main companies.   If if blows I'll just return the thing and hope they warranty it.    Now if I could just find a meter I like....

Sorry but I disagree with you; It VERY MUCH is a big deal. It isn't about the current range being the weakest, that is never mentioned or discussed. It is about the BOM and space savings. The large HRC/HBC fuses are some of the most expensive things on the board and they are some of the biggest things on the board with the fattest traces. The money saved on dropping fuses from the BOM can be used for better higher quality component selection (while keeping the same profit margin) and the savings in space can be used to better route other traces, add cut-outs etc. By cutting the fuses, you can get higher rated MOVs and PTCs, with out the fat current traces and shunt you can get extra space to add cutouts, keep outs, etc. I made just this argument  on another site (would be funny if hackaday saw that discussion and that is where they get their idea from) and am standing by it. I think this was a conscious decision by Fluke because they knew they couldn't make a safe meter, hit this price point AND keep the current function but the thing that enables the performance at this price point IS the lack of a current function. It was very clearly a conscious decision, but Fluke knew what they were doing when they dropped the current function and what it would enable them to do that they couldn't while keeping it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 08, 2015, 05:44:33 pm
I agree, it's important when you look at the economics of the $50 meter. But from evaluating the technical merits of the protection on these meters, it isn't as important. Fluke chose better components, added more creepage, used better PCBs.. it's still the aim of what Joe attempted to test and succeeded at demonstrating. Yes they had to drop current measurement for it, but no one is disputing that.

We all know you pay more for less features with Fluke. I don't think that was ever disputed. Lower end Flukes are very spartan. The aim of the test was to show which meter had best durability/protection, and in particular with the Fluke 101 weather Fluke's reputation for trustiness was justified.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 08, 2015, 07:45:58 pm
Quote
I think this was a conscious decision by Fluke because they knew they couldn't make a safe meter,
I don't know if the Fluke 101 is a safe meter or not.   I thought I had made it clear, but again, safety was never a criteria.  I was only looking for the most robust meter out of the group.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 08, 2015, 07:49:32 pm
Sorry but I disagree with you; It VERY MUCH is a big deal. It isn't about the current range being the weakest, that is never mentioned or discussed. It is about the BOM and space savings. The large HRC/HBC fuses are some of the most expensive things on the board and they are some of the biggest things on the board with the fattest traces. The money saved on dropping fuses from the BOM can be used for better higher quality component selection (while keeping the same profit margin) and the savings in space can be used to better route other traces, add cut-outs etc.
The next model in the range is the Fluke 106. It has current measurement and it costs about 50% more. The physical size is very similar (12mm longer, 5mm wider).

Fluke don't describe it as "extremely rugged" like they do 101.  :-DMM


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 08, 2015, 07:52:44 pm
Quote
I think this was a conscious decision by Fluke because they knew they couldn't make a safe meter,
I don't know if the Fluke 101 is a safe meter or not.
It does have a standardized safety-level rating stamped on it. Fluke have shown themselves to be honest and conservative with their ratings.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 08, 2015, 08:50:59 pm
Quote
I think this was a conscious decision by Fluke because they knew they couldn't make a safe meter,
I don't know if the Fluke 101 is a safe meter or not.
It does have a standardized safety-level rating stamped on it. Fluke have shown themselves to be honest and conservative with their ratings.

Talking about safety is like debating the IEC standards. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on July 08, 2015, 09:16:38 pm
Quote
I think this was a conscious decision by Fluke because they knew they couldn't make a safe meter,
I don't know if the Fluke 101 is a safe meter or not.   I thought I had made it clear, but again, safety was never a criteria.  I was only looking for the most robust meter out of the group.

This isn't an evaluation of your tests defining safety; I am saying THEIR thought process. While not intricately linked, robustness and safety do share some commonalities. Many good design practices to ensure a safe meter will also ensure a robust meter. This is to say that while the two do not have to be linked they can be. Additionally, knowing what we know about fluke, they take user safety very seriously, to the point that a meter that is robust is likely safe as well. But it is only likely, not proven.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 08, 2015, 09:21:35 pm
Quote
I think this was a conscious decision by Fluke because they knew they couldn't make a safe meter,
I don't know if the Fluke 101 is a safe meter or not.   I thought I had made it clear, but again, safety was never a criteria.  I was only looking for the most robust meter out of the group.

This isn't an evaluation of your tests defining safety; I am saying THEIR thought process. While not intricately linked, robustness and safety do share some commonalities. Many good design practices to ensure a safe meter will also ensure a robust meter. This is to say that while the two do not have to be linked they can be. Additionally, knowing what we know about fluke, they take user safety very seriously, to the point that a meter that is robust is likely safe as well. But it is only likely, not proven.

Could be.  I don't care one way or the other.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 09, 2015, 02:20:21 am
Well the moment a few of you have been waiting for is near.   I said from the beginning that I would put the winner of the $50 shootout against an expensive meter.  I've had the 87V for a few days now and it's certainly not a great meter.  Not a lot of features.  But it does cost a fair amount of money and is pretty common.   

Again, I have no plans to test beyond what I have done with the Fluke 101.  I would expect the 87V to handle all of those tests and far beyond.  I base that on the Fluke video I had linked to earlier where they were testing at 17KV.   In other words, I plan to call it a draw after I am finished with these tests, unless something happens and the sky falls or the sun goes out.   Don't worry, I won't be dropping it off a bridge to see if the LCD will crack.   If it fails it will be from an electrical event. 
 
So expect another boring video like the last few.    One thing I plan to do is also test the leads supplied with the 101.   Maybe that will add some excitement.    :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 09, 2015, 02:48:22 am
I've had the 87V for a few days now and it's certainly not a great meter.  Not a lot of features.
You seem disappointed? Not sure which features you were expecting. It's a standard multipurpose industrial DMM with all the essentials. That's the point of it. That's why it's easy to use, boots fast, and that's why it has a long battery life and longevity.

Every feature it has is implemented well. Bar graph is fast, continuity latch is fast, and the UI is easy and quick exactly because it doesn't have a lot of features. 289 has a lot of features, but at the cost of a lot of compromises in day to day usability.

I'd probably look at Agilent meters if you're looking for featureful DMMs, because they pack tons of features in their meters of the same category.

Personally I think you're being harsh on it. I think it's the best all around no frills meter Fluke ever made.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 09, 2015, 03:00:20 am
I've had the 87V for a few days now and it's certainly not a great meter.  Not a lot of features.
You seem disappointed? Not sure which features you were expecting. It's a standard multipurpose industrial DMM with all the essentials. That's the point of it. That's why it's easy to use, boots fast, and that's why it has a long battery life and longevity.

Every feature it has is implemented well. Bar graph is fast, continuity latch is fast, and the UI is easy and quick exactly because it doesn't have a lot of features. 289 has a lot of features, but at the cost of a lot of compromises in day to day usability.

I'd probably look at Agilent meters if you're looking for featureful DMMs, because they pack tons of features in their meters of the same category.

Personally I think you're being harsh on it. I think it's the best all around no frills meter Fluke ever made.

Well that is the point of having different choices. He isn't that impressed and it is his money. There are other options and that is good.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 09, 2015, 03:02:58 am
I've had the 87V for a few days now and it's certainly not a great meter.  Not a lot of features.
You seem disappointed? Not sure which features you were expecting. It's a standard multipurpose industrial DMM with all the essentials. That's the point of it. That's why it's easy to use, boots fast, and that's why it has a long battery life and longevity.

Every feature it has is implemented well. Bar graph is fast, continuity latch is fast, and the UI is easy and quick exactly because it doesn't have a lot of features. 289 has a lot of features, but at the cost of a lot of compromises in day to day usability.

I'd probably look at Agilent meters if you're looking for featureful DMMs, because they pack tons of features in their meters of the same category.

Personally I think you're being harsh on it. I think it's the best all around no frills meter Fluke ever made.

Well that is the point of having different choices. He isn't that impressed and it is his money. There are other options and that is good.
I understand, hence the reason I suggested Agilent.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 09, 2015, 09:12:03 am
So expect another boring video like the last few.    One thing I plan to do is also test the leads supplied with the 101.   Maybe that will add some excitement.    :popcorn:
Could it be done with the back off to see if there's any sparks?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 09, 2015, 09:15:35 am
I've had the 87V for a few days now and it's certainly not a great meter.  Not a lot of features.  But it does cost a fair amount of money and is pretty common.   
'Boring' is sort of the point with that meter.

(...along with other words like 'dependable' and 'trustworthy').

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on July 09, 2015, 12:30:51 pm
Nice.  I look forward to your videos!  Thanks again, for doing these tests.  The 87V is a defacto standard in that class DMM, so these tests will attract attention from a lot of professionals, particularly if it fails  :o

One thing I've puzzled about is test leads, PVC or silicone have dielectric breakdowns in > 60kV/mm range, but that is for newly manufactured leads, varies by manufacturer, and non-sustained duration: corona resistance is not a specification for test leads.

http://www.shinetsusilicone-global.com/catalog/pdf/rubber_e.pdf (http://www.shinetsusilicone-global.com/catalog/pdf/rubber_e.pdf)

For old leads subject to wear and tear, its a different story, thus its always a good idea to get new leads periodically if you deal with kV, or test it to failure as we hope to see :popcorn:


Well the moment a few of you have been waiting for is near.   I said from the beginning that I would put the winner of the $50 shootout against an expensive meter.  I've had the 87V for a few days now and it's certainly not a great meter.  Not a lot of features.  But it does cost a fair amount of money and is pretty common.   

Again, I have no plans to test beyond what I have done with the Fluke 101.  I would expect the 87V to handle all of those tests and far beyond.  I base that on the Fluke video I had linked to earlier where they were testing at 17KV.   In other words, I plan to call it a draw after I am finished with these tests, unless something happens and the sky falls or the sun goes out.   Don't worry, I won't be dropping it off a bridge to see if the LCD will crack.   If it fails it will be from an electrical event. 
 
So expect another boring video like the last few.    One thing I plan to do is also test the leads supplied with the 101.   Maybe that will add some excitement.    :popcorn:

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 09, 2015, 12:55:37 pm
The 87V is a defacto standard in that class DMM, so these tests will attract attention from a lot of professionals, particularly if it fails  :o
What are the chances of failure?  :-//
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on July 09, 2015, 02:35:48 pm
I expect low.  But we can't know for sure unless we try a surge test and demonstrate it, then its not just an educated guess.  Many things can change over time and cause problems in new DMMs versus prior runs of the same model.  A test of just one meter can be criticized, but its better than nothing.

This is one reason in the past, say in the US military, samples of a procurement were tested per batch by independent military labs to insure they live up to their specification, but I don't know if they still do this.



The 87V is a defacto standard in that class DMM, so these tests will attract attention from a lot of professionals, particularly if it fails  :o
What are the chances of failure?  :-//

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 10, 2015, 03:07:50 am
You seem disappointed? Not sure which features you were expecting. It's a standard multipurpose industrial DMM with all the essentials. That's the point of it. That's why it's easy to use, boots fast, and that's why it has a long battery life and longevity.

Every feature it has is implemented well. Bar graph is fast, continuity latch is fast, and the UI is easy and quick exactly because it doesn't have a lot of features. 289 has a lot of features, but at the cost of a lot of compromises in day to day usability.

I'd probably look at Agilent meters if you're looking for featureful DMMs, because they pack tons of features in their meters of the same category.

Personally I think you're being harsh on it. I think it's the best all around no frills meter Fluke ever made.

The 87V is just over $400 now on Amazon.  For that price, I am disappointed in what the meter can and can't do.   Really what it comes down to is if the 87V is at least as robust as the 101.   That was my end goal for this experiment and I will see it through. 

Keysight never returned my attempts to contact them.   Watching Dave's reviews on the one with those buried fuses, it's as bad as the 87V.   It has the features I want but I have concerns on just how robust it would be.    To be honest, at this stage they would have to provide me with a meter to test knowing it could be damaged before I would consider it.   

I expect low.  But we can't know for sure unless we try a surge test and demonstrate it, then its not just an educated guess.  Many things can change over time and cause problems in new DMMs versus prior runs of the same model.  A test of just one meter can be criticized, but its better than nothing.

This is one reason in the past, say in the US military, samples of a procurement were tested per batch by independent military labs to insure they live up to their specification, but I don't know if they still do this.

The 87V is a defacto standard in that class DMM, so these tests will attract attention from a lot of professionals, particularly if it fails  :o
What are the chances of failure?  :-//


This is an excellent point.   I was very happy when another member took it upon themselves to run similar tests on the 101 (Well, that is until I stepped things for that last round  :-DD).  I would like to see a second 87V tested as well just so we have two data points.     Even then, that's too small of a sample size.     I'm sure Fluke already has the answer as that video made it sound like they test every design to failure. 

From what I understand from all of the posts I have read about the amount of money Fluke has invested in making their designs robust, and the 87V being a very popular meter and how long they have had to improve their designs, and again we are talking about it just doing as well as the lowest cost meter Fluke offers.  It doesn't even have to exceed it!   I assume the chances of a failure are very low.   

So expect another boring video like the last few.    One thing I plan to do is also test the leads supplied with the 101.   Maybe that will add some excitement.    :popcorn:
Could it be done with the back off to see if there's any sparks?

It would be better to leave the meter sealed to avoid adding any variables to the test.   

It's been a very long 5 weeks.  Thanks for being patient and supportive.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 03:29:53 am
Quote
The 87V is just over $400 now on Amazon.  For that price, I am disappointed in what the meter can and can't do.

That is why I suggested a Brymen BM829 (Greenlee DM830) or a BM869 (Greenlee DM860). For the price, their functionality is hard to beat. The Keysights are good too of course.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on July 10, 2015, 04:30:16 am
One year warranty only, no AutoHold feature, no latched continuity, short battery life, Peak hold 800mS minimum transient only, no Null in central position on the bargraph, double the burden voltage on mA, lower diode test voltage, tiny selector switch. There is a lot not to like on the Brymen meter, compared to the Fluke 87V.

In my view, the lifetime warranty alone is worth the price difference.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 10, 2015, 04:53:18 am
Quote
The 87V is just over $400 now on Amazon.  For that price, I am disappointed in what the meter can and can't do.

That is why I suggested a Brymen BM829 (Greenlee DM830) or a BM869 (Greenlee DM860). For the price, their functionality is hard to beat. The Keysights are good too of course.

It is my understanding that the meter must cost a lot for it to be any good and that it must be a name brand.  If I tested a meter that was less than $300, there are some (including myself) that would feel we did not met the higher cost target.    For the brand, Fluke seems to be very popular.   So we push ahead with the popular/robust 87V.   

If any of the other brands are any good for what I need,  consider that pretty much every handheld I damaged during these tests was better than every other handheld I have owned, the bar is set low.   :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 05:44:28 am
The 87V is just over $400 now on Amazon.  For that price, I am disappointed in what the meter can and can't do.   Really what it comes down to is if the 87V is at least as robust as the 101.
The price seems to have spiked recently for some reason.
(https://i.imgur.com/g1QQkTj.png)
I can see that being an issue. I've scored mine on Ebay for much less, so I may have a different perspective.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 05:46:09 am
Quote
The 87V is just over $400 now on Amazon.  For that price, I am disappointed in what the meter can and can't do.

That is why I suggested a Brymen BM829 (Greenlee DM830) or a BM869 (Greenlee DM860). For the price, their functionality is hard to beat. The Keysights are good too of course.
BM829 doesn't have a latched continuity test nor does it have auto hold, which in my view are essential features for a DMM. So I fail to see how their functionality is hard to beat, when pretty basic and commonly used features are missing.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 06:02:50 am
One year warranty only,
Greenlee is lifetime, as has been said many times

no AutoHold feature, no latched continuity, short battery life, Peak hold 800mS minimum transient only, no Null in central position on the bargraph, double the burden voltage on mA, lower diode test voltage, tiny selector switch. There is a lot not to like on the Brymen meter, compared to the Fluke 87V.
Yes, everyone has their preferences. There are many benefits to the Brymens (Greenlee) that the 87V does not have. I do not want to have to list them again for the nth time, but I guess I need to.

The BM869s has 50000/500000 counts, better DC and AC volts accuracy, better DC and AC current accuracy, AC+DC TRMS selectable on volts and amps, dual display, PC connection option, dual temperature, CATIV/1000V, dBm, 100kHz ACV bandwidth, 1Mhz frequency counter, the 87V does 250uS for repetitive peak detect but 1mS for one shot and BM869s does 0.8mS, 41 segment bar graph at 60 updates per second, 5 updates per second on the display . All of this for a lower price.
BM869s with one year warranty: $310 or less shipped worldwide
Greenlee DM860a with lifetime warranty: $360 shipped in the US

Fluke 87V: $400 shipped in the US

In my view, the lifetime warranty alone is worth the price difference.
And again if that is the main worth, the Greenlee rebadges have lifetime warranty too.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 06:06:40 am
BM829 doesn't have a latched continuity test nor does it have auto hold, which in my view are essential features for a DMM. So I fail to see how their functionality is hard to beat, when pretty basic and commonly used features are missing.

What you are doing is saying that these two functions are important to you and therefore all other benefits do not count. But that is to you, not everyone. Everyone has different wants or needs. If you want a Fluke for your reasons then I am happy that you have a Fluke. If you want something else, then I am just stating what is offered in another brand so it can be considered.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 06:11:28 am
better DC and AC volts accuracy, better DC and AC current accuracy, AC+DC TRMS selectable on volts and amps, dual display,
Better spec sheet accuracy which doesn't mean much. We all know Fluke, Keithley, Keysight add a lot of margin in their accuracy figures. Brymen certainly hasn't been around long enough to earn that reputation.

50K+ resolution on a DMM is overrated. Brymen BM869s is missing essential features that are actually important on a DMM. 87V doesn't just have a better battery life it has at least 4 times better battery life.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 06:19:36 am
better DC and AC volts accuracy, better DC and AC current accuracy, AC+DC TRMS selectable on volts and amps, dual display,
Better spec sheet accuracy which doesn't mean much. We all know Fluke, Keithley, Keysight add a lot of margin in their accuracy figures. Brymen certainly hasn't been around long enough to earn that reputation.

50K+ resolution on a DMM is overrated. Brymen BM869s is missing essential features that are actually important on a DMM. 87V doesn't just have a better battery life it has at least 4 times better battery life.

Brymen has been making Amprobe, Extech and other brands for many years. How long is not long enough?

You are demonstrating your preferences, and that is fine. You are also making assertions without facts based on your preferences. OK, whatever.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 06:22:28 am
Back on topic:

joeqsmith:

I am sure that the 87V will pass the tests and you will learn to like it. It is a great multimeter with many good characteristics. It has a following for a reason.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on July 10, 2015, 06:31:33 am
Greenlee is lifetime, as has been said many times
Again, I have searched on Greenlee's website and there is no concrete number of years as to what "lifetime" means like Fluke's warranty (Fluke 87V is minimum 10 years to buyer who purchased from authorized Fluke dealer).

What does Greenlee's limited lifetime warranty in terms of years to a buyer?  Is it 5?  Is it 10?  Is it 20?  Is it 100?  Greenlee needs to provide a number.  Limited lifetime is a marketing term that can mean anything.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 06:41:03 am
better DC and AC volts accuracy, better DC and AC current accuracy, AC+DC TRMS selectable on volts and amps, dual display,
Better spec sheet accuracy which doesn't mean much. We all know Fluke, Keithley, Keysight add a lot of margin in their accuracy figures. Brymen certainly hasn't been around long enough to earn that reputation.

50K+ resolution on a DMM is overrated. Brymen BM869s is missing essential features that are actually important on a DMM. 87V doesn't just have a better battery life it has at least 4 times better battery life.

Brymen has been making Amprobe, Extech and other brands for many years. How long is not long enough?

You are demonstrating your preferences, and that is fine. You are also making assertions without facts based on your preferences. OK, whatever.
I am speaking purely pragmatically about Brymen here.

If the intended purpose is a general purpose day to day DMM, you want something quick and dependable. With essential features implemented well, with long battery life. When you grab a meter you want it to work.

Latched continuity and auto hold are essential day to day features.

Even the 20K high res mode on 87V has limited use, because most of the time you just want to measure a value and the extra digits don't really help you, it just makes the number longer to read, the least significant digits are pretty much always inconsequential.

And I am not saying high resolution is useless, there are plenty of uses for high resolution measurements with a proper heat compensated bench DMM. But on a go to hand held DMM it's very low on the list of important features.

And I am not singling out Brymen here, I think Fluke's own 289 fails at this as well for much of the same reasons, although at least it has a proper continuity test and auto hold.

I just think it's misleading suggesting Brymen 869 as an alternative to 87V as this super bargain with tons of features without also mentioning its major shortcomings.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 06:55:45 am
Quote
Lifetime Limited Warranty
Greenlee Textron Inc. warrants to the original purchaser of these goods for use that these
products
will be free from defects in workmanship and material for their useful life, excepting normal wear and
abuse. This warranty is subject to the same terms and conditions contained in Greenlee Textron Inc.’s
standard one-year limited warranty

I agree it is not necessarily well defined. "useful life"?

http://definitions.uslegal.com/u/useful-life/ (http://definitions.uslegal.com/u/useful-life/)
Quote
Useful Life is the expected period of time, in years, during which a depreciating asset will be productive. It is the number of years, as set by the IRS, that depreciable business equipment or property is expected to be in use. The IRS has a depreciation table for almost every item, including computers, vehicles, and other equipment.

Not much clearer to no legal types, but one list of depreciation for tools says 20 years s a suggested "useful life".

This assumes that Greenlee is asserting this legal definition for their warranty. I contact them tomorrow to get an official word.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on July 10, 2015, 07:00:53 am
Greenlee sells pipes and fishing gear. Who is to say they will still sell rebranded Brymen meters 10 years down the line?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 07:05:05 am
I just think it's misleading suggesting Brymen 869 as an alternative to 87V as this super bargain with tons of features without also mentioning its major shortcomings.

It has shortcomings to you, just as the 87V has shortcomings to others. I have stated many times what are the advantages of the 87V and other Flukes. I just did again in this thread. What you like, others don't care. What others like, obviously don't impress you much neither. It is demonstrably true that the BM869s has more features and more accuracy than the 87V and for a lower price. It is also demonstrably true that the 87V has some features that are preferred over everything that the BM869s has. One person's preference should not dictate the "truth".
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 07:07:03 am
Greenlee sells pipes and fishing gear. Who is to say they will still sell rebranded Brymen meters 10 years down the line?

Please, don't start making red herrings.  Fluke could go bankrupt, or a new owner buy them just to run them into the ground, or the world could end.... ::)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 07:11:50 am
I just think it's misleading suggesting Brymen 869 as an alternative to 87V as this super bargain with tons of features without also mentioning its major shortcomings.

It has shortcomings to you, just as the 87V has shortcomings to others. I have stated many times what are the advantages of the 87V and other Flukes. I just did again in this thread. What you like, others don't care. What others like, obviously don't impress you much neither. It is demonstrably true that the BM869s has more features and more accuracy than the 87V and for a lower price. It is also demonstrably true that the 87V has some features that are preferred over everything that the BM869s has. One person's preference should not dictate the "truth".
Not having a latched continuity or auto hold or a much shorter battery life aren't preferences. They are real shortcomings on the Brymen 869 part when compared to 87V.

Nobody would prefer to have a 100 hour battery life over the 400 hour battery life. Nobody would prefer not to hear a continuity short or open. Ok some may not even realise how useful Auto Hold is.

I know you have a vested interest in presenting Brymen in the best possible light because you use EEVB to push your product. But please don't try to turn this on some fictional preferences I have. They are real tangible shortcomings.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 10, 2015, 07:21:22 am
Again accusations of me lying to sell product. You guys are really something. You make assertions based only on your preference and call anyone else who does not agree not educated. Logical fallacies and ad hominem  attacks always demonstrates something doesn't it?

Sorry joeqsmtih for suggesting you might be happier with the BM869s when you stated your disappointment with the 87V. Obviously your opinion is worthless to them too and my suggestion was uneducated and only in my interest.

I will not contribute anymore to polluting your thread by arguing. Sorry it came to this. Your hard work and time deserved more respect.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 07:22:41 am
Again they are not preferences. Try to acknowledge faults in your own products and you might have better arguments.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on July 10, 2015, 08:07:27 am
Again they are not preferences. Try to acknowledge faults in your own products and you might have better arguments.
Until you attempt to walk the tightrope of a supplier vs a keen electronics enthusist you'd never know.

We select products WE can stand behind, have confidence and trust in, AND KNOW there are many that for one reason or another cannot see what we see and rightly so, have their own opinions.

Is X product better than Y product, of course it is.
Beauty is in the eye of the beholder, it is a lesson we must all learn.

Live and let live.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 08:39:58 am
Again they are not preferences. Try to acknowledge faults in your own products and you might have better arguments.
Until you attempt to walk the tightrope of a supplier vs a keen electronics enthusist you'd never know.

We select products WE can stand behind, have confidence and trust in, AND KNOW there are many that for one reason or another cannot see what we see and rightly so, have their own opinions.

Is X product better than Y product, of course it is.
Beauty is in the eye of the beholder, it is a lesson we must all learn.

Live and let live.
Brymen has its merits. I've also stated in the past, if one of the features it offers are a must then yes. Also the price is pretty compelling. And frankly compared to $400+ on a Fluke 87V I can absolutely see it being a better buy in some cases.

But I was talking about tangible shortcomings that weren't being acknowledged and instead dismissed as just my preferences. Fast latched continuity isn't just a preference. It's superior solution. There is a real reason for it. And that reason is that without it a human ear cannot detect short changes in continuity.

Now one can choose to not care about fast latched continuity and that's absolutely fine. But don't just call it a preference as if the alternative solution is comparable. It's not. It's inferior.

After all this is an engineering forum, not a fashion one.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 10, 2015, 09:38:51 am
I have to say one more thing and then I am done on this topic. Perhaps I was too harsh on Lightgages.

We all have our biases, but he's generally a really helpful part of this community and I think it was unfair of me to call out his conflict of interest in the exchange.

It was a cheap shot and I should be better than that. Sorry Lightgages.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 10, 2015, 01:23:11 pm
Again accusations of me lying to sell product. You guys are really something. You make assertions based only on your preference and call anyone else who does not agree not educated. Logical fallacies and ad hominem  attacks always demonstrates something doesn't it?

Sorry joeqsmtih for suggesting you might be happier with the BM869s when you stated your disappointment with the 87V. Obviously your opinion is worthless to them too and my suggestion was uneducated and only in my interest.

I will not contribute anymore to polluting your thread by arguing. Sorry it came to this. Your hard work and time deserved more respect.

I would have added a Bryman to the test if they offered one in the $50 price range with a CAT III 600V rating.   The Ex-Tech I tested did not do very well.   In the next video I plan to show the 87V compared with another meter.   Don't expect me to do a full meter review but I thought there were a couple of things that were worth including. 

Personally, I don't mind people presenting alternatives.   There is no way I can afford test every meter out there.   Of course, if you sell products, there is always going to be a conflict of interest (intended or not).   

I have to say one more thing and then I am done on this topic. Perhaps I was too harsh on Lightgages.

We all have our biases, but he's generally a really helpful part of this community and I think it was unfair of me to call out his conflict of interest in the exchange.

It was a cheap shot and I should be better than that. Sorry Lightgages.

 :-+

BTW, that's a huge price difference!!!???   I wonder why it bounces around so much.   The 28II was actually less when I checked and it is sold as a more robust meter.   :-//

Hope to have the video up in the next day.   Get ready for it!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dadler on July 10, 2015, 06:09:07 pm
BM869s with one year warranty: $310 or less shipped worldwide

Hmm http://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/bm869s/ (http://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/bm869s/)

$220.68, plus I paid $8 DHL two day shipping to California, USA. It may cost more to ship "worldwide".

So perhaps "or way less"...
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 10, 2015, 10:34:00 pm
Only one meter will survive as the Fluke 87V is put against the Fluke 101.   

https://www.youtube.com/watch?v=6GyoulNOPD4 (https://www.youtube.com/watch?v=6GyoulNOPD4)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on July 10, 2015, 11:10:01 pm
Joe, sit back and have a well deserved rest.
Great work, we are all in your debt.
 :clap:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 12:23:43 am
That 101 can sure take the abuse. Nice conclusion to the tests.

Were you testing at 12Kv? (not sure if that was the latest iteration of your transient generator box).

I'd still give good marks to the 87V in that test. No arcing, failure in one range of a non voltage measurement function. Way beyond the point of where all the other meters failed (3Kv?).

Hopefully you can get your 87V repaired.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: miguelvp on July 11, 2015, 12:45:22 am
Hopefully you can get your 87V repaired.

He did in the video. Unless I dreamt it since I was watching the video in bed.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 12:54:33 am
Hopefully you can get your 87V repaired.

He did in the video. Unless I dreamt it since I was watching the video in bed.
You didn't I missed that part, somehow.  |O
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 11, 2015, 01:23:16 am
Joe, sit back and have a well deserved rest.
Great work, we are all in your debt.
 :clap:

Thanks. 

That 101 can sure take the abuse. Nice conclusion to the tests.

Were you testing at 12Kv? (not sure if that was the latest iteration of your transient generator box).

I'd still give good marks to the 87V in that test. No arcing, failure in one range of a non voltage measurement function. Way beyond the point of where all the other meters failed (3Kv?).

Hopefully you can get your 87V repaired.

Sorry but I have been running on autopilot for a while now.   I misspoke in a few places during the video.  The surge test was 13KV peak, 100us FWHH, 2ohm source, about 10 second recharge time, three hits per function, both +/-.   No changes were made to the generator from when it was used to test the 101. 

You can be sure, if parts where blown apart like this, there was an arc.   Who knows what that would do with some real energy behind it.   

For $412 US, I expect that the 87V would exceed the 101 in every way!   If the defense for the 87V is that you don't care about the robustness, then I would suggest there are many meters that may be better suited for your needs.    I am not willing to lower my expectations like this.  Fluke are the ones showing their videos of all of the dangers when working with high energy sources, they are the ones showing how far they will go to insure the robustness of their products.     Each and every meter Fluke makes should be at least as robust as their lowest cost meter!   If they can't deliver this, I am not interested.    Fluke would have to give me a meter at this point to prove to me that it would actually meet that goal before I would pay for a high end one.    All the marketing in the world will not change that.   

I would guess based on your last comment that you did not watch the full video.   During the video, I tore down the 87V, showed the damage, repaired it, retested it, then compared it with another lower cost meter.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 01:42:00 am
Yeah I since watched the whole video. (spoke too soon).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on July 11, 2015, 01:56:02 am
Interesting and entertaining videos.  Well done.

That said however, I would hardly call a one-off test of this sort any definitive test of a meter's robustness. 

Sure, if the Fluke 87 had failed spectacularly at a relatively low voltage that might say something, but that's not what happened.

If 100 fluke 87s had been compared to 100 101s across a variety of controlled tests then you might be able to make a valid conclusion about their relative "robustness".

I do think the Fluke 87V is a bit overpriced at $400 compared to its competitors but that's a different issue.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 02:06:23 am
I agree $400 is too much for an 87V. It was around $350 when this thread started. And even that was a bit steep, but ok.

So we can conclude that 101 is one hardy meter. Is it because of the lack of features that it's as robust? Perhaps.

How robust is 87V really? Is 13Kv just above its threshold of what it can take or is it just like all the other meters? We can't really say.

We know 87Vs have a reputation for robustness. And I or anyone else certainly can't ask for much more from you. You've provided great tests in all of this.

Some parts are supposed to fail (like the fuses) and this is why meters will have reinforced blast shielding in some sections. But it would take way too many resources to really measure all these variables.

Fluke doesn't seem to have creepage issues for instance (like arcing at the selector), which many of the cheap meters exhibited at far lower voltages. And perhaps some features are difficult to implement without leaving the meter exposed to transient vulnerability in a given mode.

So what I take from this is. A well designed simple bare minimum feature meter will have a better chance of surviving than a feature packed bargain. Fluke designs some good meters. But just because a meter is expensive doesn't make it more robust. The added features make it potentially more vulnerable to damage when exposed to unforeseen circumstances.

This doesn't change my mind on the 87V though. It anything it reinforces what I've been saying. A meter with a smaller set of well implemented core features is better than a feature packed meter with less well implemented essential features, because I think that more features increases the number of transient failure vectors.

Fluke 101 is just an extreme example of this. A meter with half of what I consider essential features, is practically indestructible.

Because after all both of these meters come from the same company. And I would imagine they used the same philosophy and know how to design both of these meters. One just happens to be much more capable and expensive meter.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 11, 2015, 04:15:21 am
That said however, I would hardly call a one-off test of this sort any definitive test of a meter's robustness. 

If 100 fluke 87s had been compared to 100 101s across a variety of controlled tests then you might be able to make a valid conclusion about their relative "robustness".

I assume you did not watch the entire video as this is what I stated in the conclusion.  This testing was all funded by me, using my time to design the generator and run the tests.   There is only so much I can do as one person.   From your comment, I assume you are willing to take it to the next step.    If not, that's fine too. 

Quote
Sure, if the Fluke 87 had failed spectacularly at a relatively low voltage that might say something, but that's not what happened.

Again, as I stated in the video, it was never my intention to dial the generator back down to see where the meters fail.  I only care which was the most robust.  I will never know at what level the 87V I tested would fail at, nor did I care.   I only know it is not as robust as the 101 I tested.   

Early on I also stated I had no desire to put out enough energy to cause "spectacular" failures.   There really was no point in this.   I even did a short video showing a sustained arc using a second supply.   If you plan to run your own tests, you are free of course to play with as much energy as you like.   I welcome this and I am sure there are many of us who look forward to watching your videos.   :-+   

Yeah I since watched the whole video. (spoke too soon).

Yeah, and I missed the other posts.  :-DD   Was not my intent to call you out, again...  :-DD

I agree $400 is too much for an 87V. It was around $350 when this thread started. And even that was a bit steep, but ok.

So we can conclude that 101 is one hardy meter. Is it because of the lack of features that it's as robust? Perhaps.


I tend to agree with your first comment, the 101 is one hardy meter.   

Quote
How robust is 87V really? Is 13Kv just above its threshold of what it can take or is it just like all the other meters? We can't really say.

We know 87Vs have a reputation for robustness. And I or anyone else certainly can't ask for much more from you. You've provided great tests in all of this.

As I stated above, I agree, it would be good to know where the UNI-T 139 fails as well as the 87V.   But I was really only looking for the most robust, not a metric of how they all lined up.     We can't say that the AMPROBE I tested is just as robust as the 87V because we just don't know.  It very well could be!    The UNI-T may even hold up to higher levels!    :-DD :-DD  Funny as it sounds, we really don't know.    We do know that two 101's were tested on two generators at 12KV in all modes by two different people and it had no effect on both meters.   We know that subjecting the 87V to the same tests as my 101 caused some damage to the meter.   

Quote
Some parts are supposed to fail (like the fuses) and this is why meters will have reinforced blast shielding in some sections. But it would take way too many resources to really measure all these variables.

I was planning to run a real surge test on them but the 101 exceeded the limits of what I could do.

Quote
Fluke doesn't seem to have creepage issues for instance (like arcing at the selector), which many of the cheap meters exhibited at far lower voltages. And perhaps some features are difficult to implement without leaving the meter exposed to transient vulnerability in a given mode.

So what I take from this is. A well designed simple bare minimum feature meter will have a better chance of surviving than a feature packed bargain. Fluke designs some good meters. But just because a meter is expensive doesn't make it more robust. The added features make it potentially more vulnerable to damage when exposed to unforeseen circumstances.

You must not have watched my first Fluke.  That thing arcs everywhere at the lowest settings I tested to!    Given no constraints, anything could be built.    As I stated in the video, it would have been interesting to run the 28II which is supposed to be the more robust meter on the generator and see if it holds up. 


Quote
This doesn't change my mind on the 87V though. It anything it reinforces what I've been saying. A meter with a smaller set of well implemented core features is better than a feature packed meter with less well implemented essential features, because I think that more features increases the number of transient failure vectors.

Fluke 101 is just an extreme example of this. A meter with half of what I consider essential features, is practically indestructible.

I agree, if people want a robust meter, they should spend $50 on the 101 and not $400 on the 87V.    Keep in mind again that the Klein Tools and Gardner bender both had even less features so they should have been even more robust but they were not.    And meters like the AMPROBE with all of it's features should have failed much earlier than the Klein Tools, which it did not.   

Quote
Because after all both of these meters come from the same company. And I would imagine they used the same philosophy and know how to design both of these meters. One just happens to be much more capable and expensive meter.

The 101 is not searchable on the USA site.  It could be it was farmed out and the engineers who designed it just did a better job with the requirements they were given.   I have no idea.    AMPROBE is also built by the same company and it fell far short from the Fluke 101.   In the end it really makes no difference.   Every meter is going to be different.  The goal was to see which was the most robust.   Those who followed along watched a $50 Fluke 101 that had been beat down, over and over for several weeks, withstand what a $412 Fluke 87V could not.  Any way we want to twist the story, that was the end result.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on July 11, 2015, 04:56:18 am
That said however, I would hardly call a one-off test of this sort any definitive test of a meter's robustness. 

If 100 fluke 87s had been compared to 100 101s across a variety of controlled tests then you might be able to make a valid conclusion about their relative "robustness".

I assume you did not watch the entire video as this is what I stated in the conclusion. 
Yet in several of your posts you seem to be making that claim.

Quote
This testing was all funded by me, using my time to design the generator and run the tests.   There is only so much I can do as one person.   From your comment, I assume you are willing to take it to the next step.    If not, that's fine too.

As I said, they were great videos.  Kudos. Not sure why the defensive tone. I have no interest in doing such testing myself. Is one not allowed to comment or point out limitations of a test? 

Quote
.   
Early on I also stated I had no desire to put out enough energy to cause "spectacular" failures.   There really was no point in this.
Yes, I realize that and I was not claiming otherwise.

My point was that only a failure at a lower voltage with arcing or something of danger to the user would present any meaningful knock on the 87V's  "robustness".

Look,I watched (most) of your videos and I think they're great! :-+  Don't mistake my pointing out the limitations of what conclusions can be drawn as some sort of fatal criticism. Yes, you have stated many of the limitations yourself but you also repeatedly make generalized conclusions based on the tests which I find unjustified.  I think it is very legitimate on an engineering blog to point these out for discussion. Don't take it personally.

I just don't think this test justifies making any generalized statements about relative robustness of a Fluke 101 versus a Fluke 87V. 

In the end, any test with an n=1 is just anecdotal in nature and not evidence. But it does make for fun viewing an interesting discussion.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on July 11, 2015, 04:58:54 am
I am 100% surprised that the 87V did not survive the same treatment as the 101.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on July 11, 2015, 05:12:14 am

I agree, if people want a robust meter, they should spend $50 on the 101 and not $400 on the 87V.   

But what if someone wants a robust full featured meter?   Agreed that based on your testing the Fluke 101 appears to be a very robust pocket meter. I think your testing surprised a lot of people on how robust that little meter is. But its features are limited.

As I said before, I agree that $400 is too much for an 87V , but what else with its feature set matches its build quality and accuracy?  One of the Brymens maybe?

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 11, 2015, 06:16:36 am
Quote
I have no interest in doing such testing myself.
And why does this not surprise me??

Quote
Is one not allowed to comment or point out limitations of a test? 
Pointing out what I have already pointed out is pointless but if you feel there is a point to it pointing, point away...  :blah: :blah: :blah:

Quote
Yes, you have stated many of the limitations yourself but you also repeatedly make generalized conclusions based on the tests which I find unjustified. 

I agree, if people want a robust meter, they should spend $50 on the 101 and not $400 on the 87V.   

But what if someone wants a robust full featured meter?   Agreed that based on your testing the Fluke 101 appears to be a very robust pocket meter. I think your testing surprised a lot of people on how robust that little meter is. But its features are limited.


This must be one of my repeated generalized conclusions you mentioned.   If you are asking for a recommendation,  I don't have one.  As lightages and others have stated many times, there is more to picking a meter than just one metric.     I do agree on your comment about the 101 having limited features and will go one step further and say all handled meters have very limited features!   Hello, that's why I have more than hand held meters to play with!   Dang, you are right!  Everything I seem to post IS generalized!   :-DD   

Quote
My point was that only a failure at a lower voltage with arcing or something of danger to the user would present any meaningful knock on the 87V's  "robustness".

Do you think when the backs blow off the devices, there's no arc?   Do you think if an arc is small, it presents no risk of danger?   Do you think if an arc is small that there is no chance that it can grow?   

Again, you may want to consider there was no line voltage to sustain an arc for a reason.

There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

I am 100% surprised that the 87V did not survive the same treatment as the 101.

We may not always see eye to eye but in this particular case I am right there beside you!!  I was floored.  But this is why we run the tests.    I would really enjoy having someone repeat a test like this with a brand new 101 and an 87V.   We have one other member with a real IEC generator.   Who knows, that 87V may just fail at 12KV, 50us FWHH.    Maybe a few of you could help defer the cost if they offered to run it.   The nice thing about going that route is then anyone could repeat this test using a standard generator.   They can also increment the voltage as they did with the 101.  If it does fail, it may provide some insight at what level.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 06:29:40 am
...
101 sure impressed, but I was also impressed by the Amprobe 510 which failed from much less of a transient than 87V. In fact your tests made me recommend it to a few people. I think it's a great little meter for someone just starting. That's the perspective I am coming from, not some spin.

Your poor experience with a 40 year old Fluke bench meter certainly stands but that's a bit apples and oranges comparison. Great progress has been made in almost every aspect of electronic design and manufacturing since then. 4-6 layer PCBs, components with built in protection, more focus on safety, CAT safety standards... the list goes on. I think back then the DMM industry was still trying to pull of a working DMM design off the ground, and they were still coming up with features we take for granted today. It's a bit unfair to paint today's products on account of shortcomings of products from 40 years ago.

Also 13Kv is nothing to sneeze at. That's quite a bit more of a transient than what all the meters that failed next to 101 were subjected to.

87V survived that same 13Kv zap in all the modes but the Ohm mode. I think that's pretty darn good. It's well beyond the CAT IV spec, which doesn't even cover wrong modes.

I think 87V did well. Not as impressive as 101 but still pretty good. I got both meters. 101 is a cool little meter, but it's not at all in the same league in terms of usability as the 87V.

I could not rely on a Fluke 101 as my main meter as it simply lacks essential features. First one being the lack of a tilting bail. But thanks to all your awesome efforts now I know  87V can safely survive 13Kv transients, provided I use the right mode  :)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on July 11, 2015, 06:31:23 am
Wow Joe.  Have a beer or something....

Well said Muxr. I agree.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 11, 2015, 07:35:11 am
Quote
Your poor experience with a 40 year old Fluke bench meter certainly stands but that's a bit apples and oranges comparison. Great progress has been made in almost every aspect of electronic design and manufacturing since then. 4-6 layer PCBs, components with built in protection, more focus on safety, CAT safety standards... the list goes on. I think back then the DMM industry was still trying to pull of a working DMM design off the ground, and they were still coming up with features we take for granted today. It's a bit unfair to paint today's products on account of shortcomings of products from 40 years ago.

Once bitten twice shy.   Fool me once shame on you, fool me twice shame on me.   That first impressions are hard to erase!

101 sure impressed, but I was also impressed by the Amprobe 510 which failed from much less of a transient than 87V.

Also 13Kv is nothing to sneeze at. That's quite a bit more of a transient than what all the meters that failed next to 101 were subjected to.

87V survived that same 13Kv zap in all the modes but the Ohm mode. I think that's pretty darn good. It's well beyond the CAT IV spec, which doesn't even cover wrong modes.

I think 87V did well. Not as impressive as 101 but still pretty good. I got both meters. 101 is a cool little meter, but it's not at all in the same league in terms of usability as the 87V.

... now I know  87V can safely survive 13Kv transients, provided I use the right mode  :)


You are twisting the data which is a bad thing for people reading the posts. 
Quote
...the Amprobe 510 which failed from much less of a transient than 87V.
Of course, the AMPROBE was tested from the beginning, the 87V was not tested until the end.    The 87V was never tested at lower voltages so we do not know where it fails.    It may have failed at 2KV.  We don't know.   

You brought up the AMPROBE.  So lets consider that meter.   It made it all the way into the finals where they were tested with a 5.8KV peak,  5us FWHH, 2 ohm source.   When it failed it would still measure voltage just like the 87V.    Consider that the AMPROBE could have continued to read voltages all the way up to 13KV as well.  Again, we don't know.   I didn't care as it had failed.   

And what failed on the UNI-T UT90A?  Again, the voltages still functioned fine. 

Had I waited until the end to test the UNI-T and the AMPROBE, they too would have failed at 13KV.  That does not mean they were more robust than the other meters. 

Don't twist the data to fit your desired outcome. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 08:13:58 am
I am not "twisting any data". Fluke 87V didn't fail at 3Kv, it wasn't tested at it. But we know for sure that UT and Amprobe failed at 3Kv.

Given the experience with Fluke meters [made in this century] including the 101 I simply give it a benefit of the doubt.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on July 11, 2015, 08:34:56 am
I am not "twisting any data". Fluke 87V didn't fail at 3Kv, it wasn't tested at it. But we know for sure that UT and Amprobe failed at 3Kv.

Given the experience with Fluke meters [made in this century] including the 101 I simply give it a benefit of the doubt.
You imply the 87V failed the surge test on ohms, this is a presumption as operational checks were not done UNTIL the end of all surge tests, so who knows when/how ohms got nuked.
The fact is OHMS was nuked and to ignore this is twisting the data.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 11, 2015, 08:53:53 am
I am not "twisting any data". Fluke 87V didn't fail at 3Kv, it wasn't tested at it. But we know for sure that UT and Amprobe failed at 3Kv.

Given the experience with Fluke meters [made in this century] including the 101 I simply give it a benefit of the doubt.
You imply the 87V failed the surge test on ohms, this is a presumption as operational checks were not done UNTIL the end of all surge tests, so who knows when/how ohms got nuked.
The fact is OHMS was nuked and to ignore this is twisting the data.
Where did I ignore that ohms was nuked? Did I say it wasn't? Pretty sure I acknowledged it.

You seemed to have missed my point about the Ohms comment I made. It has to do with safety, let me elaborate since I understand it may not be as obvious, sorry.

Transients may happen unexpectedly. Let's say you're measuring a mains circuit and a transient nukes your voltage reading without you realizing it. You continue measuring thinking the circuit is not powered on. Can you see how dangerous this could be?

So independent of the mode the meter was in when it failed (all modes were tested), we can agree that if you're going to lose one function of a meter while dealing with high voltage circuits it is better if that function isn't related to indicating dangerous voltages. And in fact this is exactly what the CAT rating attempts to certify. As far as I know CAT doesn't deal with Ohms at all. And according to Joe's test Fluke 87V passes this aspect of it with flying colors way beyond the required rating.

As far as which mode the meter was in when the ohms got nuked we can only speculate, so there is no data to be twisted, since the meter wasn't tested between each mode.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dadler on July 12, 2015, 01:38:28 am
There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?

How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?

Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 12, 2015, 01:57:08 am
There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?
As I stated before, I would not trust any meter without personally testing it.  I also have said I would never work on 440 and that I'm not trained for this.     

Quote
How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?
It doesn't.

Quote
Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?
At most I use it to measure 220 line CAT II stuff which I do not consider high risk.   Even that is rare for the work I do.     So to answer your question, no.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on July 12, 2015, 02:00:47 am
There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?

How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?

Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?


The 87V has a well deserved reputation for safety and accuracy based on experience of thousands of users over the span of almost 2 decades.  Nothing in his tests contradicts this and if anything confirms it, as Muxr pointed out.

Confirmation Bias (https://en.wikipedia.org/wiki/Confirmation_bias) is something that we're all susceptible to.

The 87V may be overpriced, but that is an entirely different matter.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dadler on July 12, 2015, 03:03:30 am
There is no way I would trust my life with the 87V.  That may seem like an unfair comment to a few of you but again, as so many of you have pointed out, what is my life worth.  It sure seems like there were a few that were quick to point out that spending more money buys safety.   Well my life is worth a lot more to me than risking it with a meter that I know fails at a lower energy than a $50 meter.

This logic does not follow for me. Would you trust your life with the 87V if the 101 never existed, or you had never tested it?
As I stated before, I would not trust any meter without personally testing it.  I also have said I would never work on 440 and that I'm not trained for this.     

Quote
How does the cost of one particular meter affect how much life-trustiness you would put in a different meter?
It doesn't.

Quote
Would you trust your life to the Extech that you gave the testimonial about at the end-- the same one you said you wouldn't subject to the tests?
At most I use it to measure 220 line CAT II stuff which I do not consider high risk.   Even that is rare for the work I do.     So to answer your question, no.

Ok, thanks for the clarification. I am glad you have run these tests, they are interesting--thanks for that.

I do think you are being at best imprecise and at worst quite wishy-washy with your conclusions.

As I read your words, you are essentially concluding that since the $50 fluke did not (seemingly/immediately) fail at a specific extreme test voltage, a more expensive meter that did (seemingly/immediately) fail at the same specific extreme test voltage is not safe.

If the 87V fails in some spectacularly minor way (with a test sample of one), when subjected to conditions far exceeding its ratings, I think it is not fair to conclude that it is not a safe device--That you wouldn't "trust your life with it".

Basically, I consider your argument to be a non sequitur.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on July 12, 2015, 05:28:31 am

I do think you are being at best imprecise and at worst quite wishy-washy with your conclusions.

That's fine.  I thought the conclusions were pretty clear.  The Fluke 87V did not survive the same tests that I put the Fluke 101 through.

As I read your words, you are essentially concluding that since the $50 fluke did not (seemingly/immediately) fail at a specific extreme test voltage, a more expensive meter that did (seemingly/immediately) fail at the same specific extreme test voltage is not safe.

That's what you got from it?    I would not consider any meter safe which I thought would have been made very clear by now.   I guess three devices with their backs blown off would be considered "seemingly".

If the 87V fails in some spectacularly minor way (with a test sample of one), when subjected to conditions far exceeding its ratings, I think it is not fair to conclude that it is not a safe device--That you wouldn't "trust your life with it".  Basically, I consider your argument to be a non sequitur.

Argument?  You asked me specific questions, I provided you answers.    In the end, the Fluke 87V was damaged by a transient that the Fluke 101 had no problem with.   

I have no idea what safe is,  but yes, I certainly would not risk my life with the 87V measuring a 440 main but again I wouldn't risk it with the 101 which appears even more robust or any other meter out there.  Maybe this is the part you feel is irrelevant.   

Do I think using the 87V places me at a higher risk than the 101, yes because it failed at a test that the 101 survived but that risk is minimal for me because as I have stated, I don't typically work on systems where I am at exposed to lethal energy levels.   There is always my home made attenuator that I mentioned to limit the risk as well.   

I am also not going to spend hundreds on a meter that is not as robust as a $50 product so I can measure non-lethal circuits.  Nor will I spend hundreds on a meter that can't calculate AC+DC.     

Well, I hopefully cleared up a few things.      If I get another meter from Fluke or find another one that will pass the last test setup, I will post about it, otherwise I'm on to the next project.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: oldway on July 12, 2015, 11:54:01 am
These tests are interesting but do not correspond with reality.

As an engineer in power electronics, what especially interests me is what happens with the multimeter when measuring a voltage like 550VDC on a 5000A DC drive and that there is an arc in the multimeter which occurs due to a transient voltage.

When there is great power in play, things go completely differently from what is seen in this test.

The simple harmless arc turns into a real explosion.

Therefore, on one hand, high voltage transients are not interesting  because they are improbable, on the other hand, it is irrelevant whether or not the meter is still functional, what matters is that the operator has not been hurt nor killed.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on July 12, 2015, 12:16:16 pm
Do I think using the 87V places me at a higher risk than the 101, yes because it failed at a test that the 101 survived

We've only seen one set of test conditions. The 101 might fail much more catastrophically than the 87V in real high-energy situations.

Bottom line: Connecting a multimeter up to a genuinely high energy device is dangerous. You need to think very carefully about how you approach it.

The best approach is not to do it at all and Waltzing up to it with a probe in either hand and the meter between your teeth isn't the way to go even if you did pay $5000 for the meter.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: oldway on July 12, 2015, 12:40:59 pm
Quote
Bottom line: Connecting a multimeter up to a genuinely high energy device is dangerous. You need to think very carefully about how you approach it.

The best approach is not to do it at all and Waltzing up to it with a probe in either hand and the meter between your teeth isn't the way to go even if you did pay $5000 for the meter.
Power electronics is not a job for everyone...You must be qualified...
If you make a mistake, you will probably never be able to make a second one !
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: hibone on July 12, 2015, 02:01:16 pm
why not rising the bar?

what about Cat. rated scopes?  >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on July 12, 2015, 04:18:38 pm
These tests are interesting but do not correspond with reality.

As an engineer in power electronics, what especially interests me is what happens with the multimeter when measuring a voltage like 550VDC on a 5000A DC drive and that there is an arc in the multimeter which occurs due to a transient voltage.

When there is great power in play, things go completely differently from what is seen in this test.

The simple harmless arc turns into a real explosion.

Therefore, on one hand, high voltage transients are not interesting  because they are improbable, on the other hand, it is irrelevant whether or not the meter is still functional, what matters is that the operator has not been hurt nor killed.

And,

Quote
We've only seen one set of test conditions. The 101 might fail much more catastrophically than the 87V in real high-energy situations.

Excellent points oldway.  This is really the crux of the matter.  Concluding anything from one (non real world) test with one meter is folly.  Basing a decision on which of those two meters to use in a real world high energy situation based on this test is outright foolish IMO.

CAT ratings (if real!) are at least somewhat better.

I am not a power electronics engineer but I've done a fair bit of work on 240V mains and on high energy PV solar installations and I know which meter I would choose for those tasks.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: oldway on July 12, 2015, 05:42:03 pm
Measuring ac and dc voltages up to 600V on high energy is an everyday task for power electronics engineer.

You need checking industrial power grid AC voltages, measuring batteries voltages of high power No breaks (up to 600V), field weakening threshold voltage (around 500V) of dc drive, and so on...

I must say I only trusted on Fluke multimeters to do that and I never had any problem.

But now, I am retired and I am not working with such dangerous voltages anymore.

Fluke 87V is a very good multimeter (I have also a 87IV, but I don't like it very much), but is far too expensive in Europe.
It should be sold for 200€, no more.

For this reason, if I would buy another multimeter, I would choose a Brymen 867's.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muxr on July 12, 2015, 06:50:52 pm
I too think Brymen is a better deal 87V is overpriced for most people. But 87V is a better meter. The only reason I have a set of 87Vs though is because you can get them on Ebay for much less, due to their popularity.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: sreeb on July 16, 2015, 02:15:34 am
From a safety perspective, it unclear to me how much value there is in a test that introduces a transient without the underlying mains voltage.

My understanding, dating from some companies long ago mandatory safety training, is that the serious danger is that the transient establishes an arc and the underlying voltage sustains it.  The video tape backed this up with lots of electrical road kill photos.

I never ended up working with high power and have never experienced transient induced arcing in real life though.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on July 16, 2015, 04:31:11 am
From a safety perspective, it unclear to me how much value there is in a test that introduces a transient without the underlying mains voltage.

My understanding, dating from some companies long ago mandatory safety training, is that the serious danger is that the transient establishes an arc and the underlying voltage sustains it.  The video tape backed this up with lots of electrical road kill photos.

I never ended up working with high power and have never experienced transient induced arcing in real life though.
Welcome to the forum.

There has been much discussion on Joe's thread and techniques but it all comes down to tests that satisfy Joe, based on his past and overall exerience with DMMs so that HE is happy to use a particular brand/model.
The real outcome is a new CAT standard, Joes standard, a standard that means more to him than anyone else.

CAT joeqsmith  :-+


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on July 16, 2015, 05:58:36 pm
Its a bit late but I hadn't the time until now to read in detail, but I suspect Fluke designs its DMM to far exceed IEC impulse test voltages to allow margin for error in production, be it component quality, to assembly.  We should consider that when producing a batch of devices, a range of performance can be expected due to parts and construction tolerances, but if the Fluke design criteria far exceeds required IEC criteria, then we can expect nearly if not all production to pass IEC criteria, with individual devices being more or less robust than a sibling. 

In the JQS video, the 87V malfunctions in ohms at 13kV, but that impulse is still above its 8kV rating and other functions appear normal.  Alas, there was no function test at under 13kV.  The Fluke educational video posted earlier in this thread shows an 87V dying at 17kV in volts mode, again far above the IEC requirement, but they did not show how well it functioned between each kV impulse test.

I think the clearest take home message is the lowly entry level Fluke 101 DMM, which appears to have only CE Fluke safety certification, no 3rd party safety certification,  is likely to take surge's well, and likely meets CAT III 600V criteria.  Chances are the 101 was designed like other Fluke DMMs, to survive far over the required IEC surge voltage.

That prompted me to search if indeed the 101 and other non-sold in the US Fluke meters have had 3rd party testing, as I noticed some 101 have a CSA mark, others do not. I found the CSA listing for the 101 and several other Fluke meters not marked CSA, which means these Flukes were tested to a point independently.  The devices made it far enough in the certification processes [safety issues] to receive a listing.  Why Fluke doesn't mark them after they've been granted a listing can be due to many speculative reasons, e.g. not paying recurring fees to keep production costs low, not completing less critical items in the CSA procedures, etc.,



I expect low.  But we can't know for sure unless we try a surge test and demonstrate it, then its not just an educated guess.  Many things can change over time and cause problems in new DMMs versus prior runs of the same model.  A test of just one meter can be criticized, but its better than nothing.

This is one reason in the past, say in the US military, samples of a procurement were tested per batch by independent military labs to insure they live up to their specification, but I don't know if they still do this.

The 87V is a defacto standard in that class DMM, so these tests will attract attention from a lot of professionals, particularly if it fails  :o
What are the chances of failure?  :-//


This is an excellent point.   I was very happy when another member took it upon themselves to run similar tests on the 101 (Well, that is until I stepped things for that last round  :-DD).  I would like to see a second 87V tested as well just so we have two data points.     Even then, that's too small of a sample size.     I'm sure Fluke already has the answer as that video made it sound like they test every design to failure. 
From what I understand from all of the posts I have read about the amount of money Fluke has invested in making their designs robust, and the 87V being a very popular meter and how long they have had to improve their designs, and again we are talking about it just doing as well as the lowest cost meter Fluke offers.  It doesn't even have to exceed it!   I assume the chances of a failure are very low.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on July 18, 2015, 05:49:51 pm
As clarification, IIRC, a transient in single phase mains voltage can propagate into an arc flash if the transient can ionizes the surrounding medium enough to reduce the impedance to allow the mains voltage to conduct.  This is were creepage, clearances and pollution degree ratings matter now, too. 

The IEC transient test is very similar as JQS demonstrates, 0V to kV and later 0 to -kV.  Its not the entire CAT test, but a key part of it. 

Quote from:  link=topic=48998.msg711016#msg711016 date=1437012934
From a safety perspective, it unclear to me how much value there is in a test that introduces a transient without the underlying mains voltage.

My understanding, dating from some companies long ago mandatory safety training, is that the serious danger is that the transient establishes an arc and the underlying voltage sustains it.  The video tape backed this up with lots of electrical road kill photos.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 04, 2015, 01:22:06 am
Many of you are aware that TechnologyCatalyst or 5ky, purchased several handheld meters out of his own pocket in order to run another $50 shootout.    The thread may be found here:
https://www.eevblog.com/forum/testgear/new-$50-multimeter-shootout-15-dmms-compared/ (https://www.eevblog.com/forum/testgear/new-$50-multimeter-shootout-15-dmms-compared/)  His Youtube channel  may be found here:
https://www.youtube.com/channel/UCYVMnw_W7-Rq-yJk80vprug/videos (https://www.youtube.com/channel/UCYVMnw_W7-Rq-yJk80vprug/videos)

One of the things that was brought up was testing these meters with some sort of electrical transient.   5ky has graciously accepted my offer to run them however with a slight twist.   

After running the first set of meters and now knowing roughly how they fail and what sort of energy is needed, I plan to start over from scratch and build a new transient generator.   The reason for the new generator is simple.  It will be programmable and allow me to automate some of the testing.   This will allow me to repeat tests and hopefully not spend near the time.  The last time, the UNI-T came in late from China and was just throne  into the mix and was damaged beyond repair.   I never knew just how poor of a design it was compared with the other meters.   The same for the Fluke 87V.   It would have been nice to know just where it failed at.     

Don't expect to see and covers blowing off the meters.   New generator does not mean more energy and 20J does not do the same damage as a KJ.   Like before, I plan to keep things at levels just high enough to stress the meters input protection circuits.   So if you are looking for a lot of fire and exploding parts, look else where.   I will keep the old generator just in case one of 5ky's meters does so well I think it could pass that test.       

I purchased a new Brymen BM869s as my basic home meter (huge step up for me).   A few members have asked about how robust this meter is.   My plan is to put this meter along with the 101 into the batch.   

5ky and I have not yet spoke.  I have a lot of work to do before I will be ready.    I may do some quick videos as I start to make some progress. 

In the mean time, here is an old 80's article on surge testing to kick things off ....
http://pml.nist.gov/spd-anthology/files/Dont_kid-kill.pdf (http://pml.nist.gov/spd-anthology/files/Dont_kid-kill.pdf)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on September 05, 2015, 03:09:59 am
No rush, the meters are all in a plastic tote awaiting your word  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 06, 2015, 02:06:52 pm
Video describing the new transient generator and initial testing of the power stages.

https://www.youtube.com/watch?v=1wD7Q1N1XY4 (https://www.youtube.com/watch?v=1wD7Q1N1XY4)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 07, 2015, 03:37:20 pm
Thinking about the AC wall socket test Dave shows during some of his meter videos....

Originally I had a 2M resistor in series with the output that I injected a voltage on to see if the meter was working.   Often, I had an AC wavefrom (wall transformer) in series with a DC supply so I could check both AC and DC modes without changing the setup.

With this test jig, I was thinking to have some sort of higher power bias that could substitute for the AC wall socket test Dave shows.    I had thought about just using a transformer but I loose the DC.   In the last video, this is why I showed the rectified signal.     

I know when I was testing with my 1KV high voltage supply (good for about 1mA) it was not enough current to overcome the protection circuits in the meters.    This is why I tested using the antique Drake radio's plate supply.  This is good for 300mA average.   None of the meters I looked at presented enough load to make that supply droop.     

Can't see making an arbitrary generator that can supply KVs at 100's of mA just to stress some meters....   So leaning towards a fixed transformer with rectifier like I showed.


 :blah: :blah: :blah:
For those crappy meters that actually get damaged when connected to the 220 line,  how much current was actually required to get them to fail?   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 08, 2015, 12:11:29 am
Have the Teflon spacers installed now and finally put a probe on it.   5.5KV pulse from new generator into an open.    110us FWHH can be set shorter.     Seemed to work fine down to 600 volts.   Very repeatable.   Ran into a couple of snags.  Noticed the new Brymen BM869s can't check the high voltage diodes I am using.   Is 14 volts drop too much to ask?  :-DD   The other problem is the relay I am using to trigger the generator welded the contacts after maybe 100 cycles.     Some good progress.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 09, 2015, 03:59:30 am
Relay problem is solved.  Also after damaging the voltage sense, added protection for the amplifier.   Output stage now seems bullet proof.

I now have several damaged 25W bulbs.  This may not seem like a big deal, but while the voltage is lower than the old generator, it will put out roughly the same energy.  More than double what I damaged every meter I tested, except for that Fluke 101.    It will be very interesting to see how this new batch holds up..... 

Made up the test cable for it.   Attached picture compares new one with the original and how it fits to the Brymen.    Want to make sure that we get all that energy into the meter.....

Have a small isolation transformer on order now.   Because I have never actually seen a meter fail this outlet test,  I plan to design the system to handle
500mA.   Plan to rectify the AC to get my DC and AC bias when running the transient tests.  Will have a way to turn off this supply. 

The last major part is the controller for it.  Watching Dave's last video on the old Fluke, I was thinking to use an MC6801.   Another option I am thinking about is to run the thing headless and just use a PC with Labview.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on September 09, 2015, 05:15:30 am
Looking firward to more tests.
 :-BROKE  :bullshit:  >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on September 09, 2015, 07:43:06 am
The last major part is the controller for it.  Watching Dave's last video on the old Fluke, I was thinking to use an MC6801.   Another option I am thinking about is to run the thing headless and just use a PC with Labview.   

Not sure what you mean by "use an MC6801" - build your own microcontroller?

These days almost everything is done with Arduinos.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 09, 2015, 11:46:35 am
The last major part is the controller for it.  Watching Dave's last video on the old Fluke, I was thinking to use an MC6801.   Another option I am thinking about is to run the thing headless and just use a PC with Labview.   

Not sure what you mean by "use an MC6801" - build your own microcontroller?

These days almost everything is done with Arduinos.

The Fluke used an old Hitachi 63xx.   They had an OTP 6301 for a while.  I think there was a lawsuit over it.   Being a bit of a nostalgic buff, it may be fun to wire wrap one last board.   Maybe put a GAL on there.  :-DD   

The 6801 is a microcontroller.  No USB, CAN, Ethernet, FLASH, ADC, DAC, EEPROM.....     Does have some digital ports, serial port and PWM.    :-DD    There was talk of contest using a 1K device.   Maybe this will be my entry.   :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 10, 2015, 10:37:52 pm
Made some progress on the new generator.   I cut and squared the parts to make the case.   These are 1/4 inch thick plate aluminum (in case she blows up!!).   I'll machine the front and back once I sort out the controller for it.    The Brymen does not appear all that concerned yet.....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 11, 2015, 01:11:55 am
Unopened tube of Motorola MC68701CLs with quality guaranteed by Cristine.   



Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 11, 2015, 01:45:23 am
The original Motorola parts were typically masked at the factory.   Hitachi came out with their clone which was CMOS and they had an OTP version. 

Second picture shows my homemade programmer  for the Motorola parts.   This was the 3rd programmer I had made.   Basically is emulates a SEEQ 2816AH device.  Has a dual ported Cypress part and a Lattice GAL for the logic.   Put you 68701 in the socket and hit the switch.   LCD

The transient generator does not need too many features.  Maybe a handful of switch inputs, couple of 8-bit ADC channels,  a few digital outputs a DAC and an LCD.   Maybe a little EEPROM to store some settings.   Nothing the most basic of PIC parts would have.    This transient generator needs something a little more classic....  :-DD

Time to see if the tools will still run.... 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 11, 2015, 02:25:17 am
Dang tools will run without DOSBOX.   

Hunting in my box of old displays, most are 16X2.  The largest one I had was damaged.   The one in the back I think is an old plasma unit.   I remember these looked pretty nice but it's way too large.    When the unit is running, I would like to have everything displayed on a single menu.   Getting it all to fit in 32 characters is going to be very cryptic.     Modern technology has spoiled me....

More searching in the junk pile and I uncovered an old Noritake VFD which will be perfect for this project.

Time to wire up something.       

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 12, 2015, 04:38:36 am
Once I tried to talk to some hardware, Windows helped me out.     :--   Then DOSBOX saved the day.   :-+   

I now have a 6801 talking with the display so I went ahead and ordered the push buttons.    All the hardware is now on order to finish it.   It's starting to come together but still thinking about 2-3 weeks out before I will try it out on a meter....       
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on September 12, 2015, 06:16:44 am
I love me some dosbox.   :-+

I'm digging the retro components.  This is going to be a slick build!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 12, 2015, 11:24:09 pm
Spent the day working some more on the wire wrapping and relearning the 6801 instruction set.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on September 12, 2015, 11:28:34 pm
I am impressed. I haven't touched wire wrap since 1985?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on September 12, 2015, 11:45:22 pm
Spent the day working some more on the wire wrapping and relearning the 6801 instruction set.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=170892)
Nice rats nest.  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muttley Snickers on September 13, 2015, 12:50:36 am
I wasn't sure as to the best place to leave these pictures so I will just plonk them here for now, found the listing on ebay au and this meter does have something about it that appeals, the overall look seems familiar and possibly the enhanced safety aspect after all if you cant plug in your probes then it's about as safe as it gets.

On the other hand if people that are unfamiliar with multimeter operations and procedures are in some way guided by the input jack shield as to the correct placement of the leads and that shield fails to work as intended as seen in the picture then they are better off without it.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 13, 2015, 05:33:21 am
Sold my Ziftel (??) Slit wrap gun many years ago.   Would have made this job easier.    I think the wire wrapping is done as long as I don't add any more features.   :-DD    The basic software is now all in place and I have checked the hardware out.     

The biggest problem I see is that my basic code now takes up 2263 bytes and the MC68701CL only has 2048.   I would guess it's about 80% done and I was thinking to add a current probe with some sort of auto shutdown as well.   It's going to be tight!

Shown reading the high voltage input along with my very safe Weston meter and 500A shunt.





Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 14, 2015, 12:18:13 am
Recessed the front cover to give it a bezel look.   Drilled and tapped the holes so I could assemble it and start thinking about how I want to start mounting parts inside once they all get here.   Its a fair bit larger than the original generator and is going to be fairly packed. 


   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on September 15, 2015, 04:42:47 am
That's going to be quite a bit larger than your old rig.  Did you make that new case?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 15, 2015, 09:48:06 am
That's going to be quite a bit larger than your old rig.  Did you make that new case?

I looked into buying a case but yes, I am making the case for it from scratch.  The rest of the parts should be here tomorrow.   I hope to have the whole system assembled next weekend.   Then it's just finishing the code for it, make the cover for the case and figure out how I am going to letter it. 

Won't be much longer.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 16, 2015, 11:49:49 pm
Remember ISP Expert and CUPL?   I am turning the hands of time back further to PALASM.   :scared:   Now where is that tube of 22V10's.....

I wound the current sense and tried it out.  Looks pretty good.   Not sure if is going to do anything to help the testing.  Hard to believe a meter would actually fail in ohms mode (or any mode) when stuck across the mains.  We will see. 

I have been working on the code and am now very close with 27 bytes left over.  2K will force you to have to think.   I just need to get the logic in there to run the tests and then start debugging. 

To top it off, the last of the parts arrived today.   The little step-up transformer looks pretty good.   I'll make a second video once I get things mounted in the case.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 17, 2015, 01:17:27 am
PALASM sort of works in a DOSBOX.  The menus seem to screw up but it will compile.    Found a tube of PALs and one GAL.   Was able to get the old parallel port programmer working under Windows.   All that for a few FFs.  One more thing done.   




Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 20, 2015, 04:41:09 pm
Retro Porn. 

https://www.youtube.com/watch?v=-yIKw0YGpHk
 (https://www.youtube.com/watch?v=-yIKw0YGpHk)

Maybe teak walnut or a nice cherry....   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on September 20, 2015, 08:00:52 pm
Man you're putting some work into this thing and it shows!  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 21, 2015, 04:24:28 am
Thank you sir.      I made the mounts and plastic spacers for the HV section today and wired it in to try it.  First hit, the CPU reset.  :palm:   A few changes to the grounding seems to have taken care of that.   Captured several transients with the DSO and its very repeatable.    Another week and it should be ready for a trial run.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on September 21, 2015, 04:30:47 am
Impressive work.  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 21, 2015, 05:25:34 pm
Impressive work.  :-+

Thanks!   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 23, 2015, 03:56:03 am
More retro porn...

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: fpliuzzi on September 23, 2015, 04:36:37 am
Wow... you've created a real stunner there - literally and figuratively. Looking forward to seeing this beauty in action.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 23, 2015, 12:30:42 pm
 
Wow... you've created a real stunner there - literally and figuratively. Looking forward to seeing this beauty in action.

 :-DD

Thanks.  It's a pretty big step up from the first generators.   

I plan to make one last video showing it in operation before I start running 5ky's meters.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on September 23, 2015, 03:52:17 pm
what is the case? Not the wood part but the body. It looks REALLY nice.

Edit: The WHOLE thing looks really nice, I can't wait to see it destroy some meters.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 23, 2015, 05:25:49 pm
what is the case? Not the wood part but the body. It looks REALLY nice.

Edit: The WHOLE thing looks really nice, I can't wait to see it destroy some meters.

Thanks.  If you look back a page or so, you will see some pictures as I was making the case.  It is 1/4" thick plate aluminum.  After I had machined the face plate, I buffed it.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 24, 2015, 09:51:04 pm
https://www.youtube.com/watch?v=PJTJJodEuyA
 (https://www.youtube.com/watch?v=PJTJJodEuyA)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 25, 2015, 12:13:57 pm
Making that last video I discovered a small design flaw in my code.   If you put out say a 5KV pulse, then aborted the run, then set the generator to say 1KV, the capacitors may have been charged anywhere from 0 to 5KV.   I had assumed that once the trigger threshold was met,  send out a pulse.    I had also wanted to add another feature anyway so the generator came back apart.     Now it checks to make sure the bank has discharged below the trigger before turning on the high voltage.   

While the cover was off, I gave it a light sanding with some 600, then another coat of clear.   


I have now been in contact with 5ky about his meters from the shootout he did.   Sounds like they will arrive next week.   We all owe him a big thanks for buying these meters out of pocket, taking the time to do the reviews, then be willing to have them destroyed!   :-+  :-+   His channel is here:
https://www.youtube.com/channel/UCYVMnw_W7-Rq-yJk80vprug/videos (https://www.youtube.com/channel/UCYVMnw_W7-Rq-yJk80vprug/videos)

Will it come down to the AMPROBE 530 and the Fluke 107???     And how does my new Brymen BM869s fit in there?   Stay tuned...... :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on September 25, 2015, 08:41:03 pm
what is the case? Not the wood part but the body. It looks REALLY nice.

Edit: The WHOLE thing looks really nice, I can't wait to see it destroy some meters.

Thanks.  If you look back a page or so, you will see some pictures as I was making the case.  It is 1/4" thick plate aluminum.  After I had machined the face plate, I buffed it.

Nice work, would make a really nice design for a SFF PC case. Ever since my old CoolerMaster ATCS case that I had, I have loved thick aluminum front panels. I was hoping that it was some commercially available case. Oh well, at some point maybe I will make my own.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 26, 2015, 05:03:23 pm
Thanks.   I looked at buying a case but they were so expensive if you wanted anything a little fancy. 

Last night, while testing the generator, I was able to damage one of the FETs.   I added some additional protection for these parts, added some copper foil for a better ground plane on the wire-wrap board and added another Ferrite bead.    Tried several more times to get the unit to fail or see if I could find any more software bugs.  It's looking very solid.   

I picked up a Cen-Tech 90899 7 function meter from Harbor Freight and was planning to use it for a baseline.   When I ran the last meter like this, it died on the first hit and I wanted to make sure I could dial things down far enough were it would survive.     I took it apart and the PCB layout has changed.   They have a small fuse for the low current settings.   The mA is shared with the volt ohm input so I removed the fuse and did a quick functional test on it.   I then connected the thing  to the generator, turned on the AC to the meter, no problems.   Then I turned the knob from AC 750 with the power on and bang....   Of course, I continued to rotate the knob with more bangs and pops.  The generator detected the over current and turned off.   The control IC appears to still function somewhat.   There are a few resistors that failed.       

This is the first meter I have ever seen fail this test.   So it looks like the 500mA step-up transformer will do nicely.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 27, 2015, 12:37:46 am
Looked like P2 and 5R4 were also damaged.  Did a quick swap but appears the IC was damaged too.   

Plugged it back in and removed the IC's encapsulation with one hit. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on September 27, 2015, 04:17:12 am
I'm liking the damage I see. Lets hope for more kaboom

Sent from my LG-ls990 using Tapatalk

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on September 29, 2015, 03:32:39 am
5ky's meters are on there way and should arrive this week. 

I'm liking the damage I see. Lets hope for more kaboom

My wife saw it run for the first time tonight on that cheap Harbor Freight meter.   Gave it a 5 nice 700V hits.   It's very quite except for the beep at the end of the test.  She was not impressed but thought the case looked nice.   Then I turned it up to kill all meters mode........... CRACK!!!!  She jumped. I jumped.   I think we have the kaboom thing down.  :-DD

After killing the HF meter (which was not my intent)  I removed the protection I had added to the UNI-T UT90.   This meter made it into the final 4 before the first failure with it.   It's basically stock now except my wire trace repair may hold up a little longer.   Because the waveform is different with the new generator, this should give us some idea how the new meters compare with the old.   

Rather than using the clamp to hold the meters, I bent up a holder which is then grounded to the generator.   I did this to see if any of the cases would arc through.   Doubtful.

My plan is to do a quick functional check of the meters and replace any of the blown fuses.   
Static test them all with the grill starter
Run them at their rated DC input voltage. 
Run them off the rectified AC signal (that killed the HF meter) in all of the modes.
The Brymen BM869s will be put through these same tests along with them.   The UNI-T UT90 and Fluke 101 already have survived these tests and will not be retested.   

The meters that make it through this basic testing with no damage (other than blown fuses) will get ran with the new generator.   The Fluke 101, UNI-T and the Brymen will be tested with them as well.     

When I tested the first meters, I used a source of 50, 14 a 2 ohms.  This time, I plan to keep the source at 2 ohms throughout the entire test. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 01, 2015, 02:17:37 am
Just a quick update.   5ky's meters arrived today in good shape.    Thanks again for sending these.   I think we will learn a lot from them. 

Of the 18 meters I started with, 4 are all ready damaged and of those, one will no longer power up.    :palm:     It's good to weed out those meters that are on par with Harbor Freight's free meters.   

My bet is the Fluke 107, AMPROBE AM530 are going to be there to the end, along with my Brymen BM869s.   

Stay tuned for the first of many videos.......
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 01, 2015, 05:02:21 am
I didn't bother packing them very well, but I figured they each survived three drops from 1 meter, so light padding would probably suffice.  The ones with the three input jacks instead of three are all of the ones with blown mA range fuses.

Let the games begin!  :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 02, 2015, 02:07:04 am
No problems at all with shipping. 

I have the first video edited and will post it in the next day after I review it. 

The second round did not go as planned at all.   I started out using the UT90A thinking if that passed surely all of the other meters would pass and we could go on from there.   What happened was five more meters were damaged.   Meters I thought would have had no trouble died.  Meters I thought for sure would fail earlier lived.    :palm:

The generator is working out very well.   The testing is going much faster. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 02, 2015, 10:57:53 pm
Round 1 results showing all of the meters getting the grill starter treatment, then subjected to a KV of DC in the DC range.  Then selecting all of the modes with rectified 220VAC applied.    Sorry for you people who want to see some sparks.   I'll see if I can do something about that in the next video.... 

https://www.youtube.com/watch?v=Ohk2dqsq7dM (https://www.youtube.com/watch?v=Ohk2dqsq7dM)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 03, 2015, 01:15:07 am
Awesome!  Not super surprised the uni-t's met their fate.  It also goes to show how crap those EX series Extechs are.  If I buy another, it'll be the E series (the rebranded Brymens).   :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 03, 2015, 01:16:03 am
Also, I'm really surprised that Fluke 107 is a different size from the 101.  I figured they'd reuse the same chassis to save costs, but I guess not!  That's fluke for ya: they don't cut costs to please their accountants.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 03, 2015, 01:15:50 pm
Whoah! Great magic trick at 0:52!

Can you do it backwards - turn Uni-Ts into flukes?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 03, 2015, 08:35:00 pm
After that 87V was damaged during my initial testing,  I would like to make a video of nothing but Fluke meters to see how much their protection varies.   For now, I think just seeing how 5ky's 107 holds up compared with the 101 will be interesting.   I am just expecting the 107 will survive everything the 101 does, but I thought that about the 87V too, but now know better.   

Awesome!  Not super surprised the uni-t's met their fate.  It also goes to show how crap those EX series Extechs are.  If I buy another, it'll be the E series (the rebranded Brymens).   :popcorn:

You have too many meters as it is!!   :-DD :-DD :-DD :-DD  I am trying my best to thin your heard! >:D

Hope you enjoy it.
https://www.youtube.com/watch?v=2YG6FjEkyXs
 (https://www.youtube.com/watch?v=2YG6FjEkyXs)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 03, 2015, 08:40:18 pm
Also, I'm really surprised that Fluke 107 is a different size from the 101.  I figured they'd reuse the same chassis to save costs, but I guess not!  That's fluke for ya: they don't cut costs to please their accountants.
Adding amps measurement means it needs fuses inside.

And maybe bigger track gaps ... although that wouldn't make it much bigger.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 04, 2015, 12:52:13 am
From the pictures I have seen of the 101 and 107, they don't look at all the same.   One look at the 101 and you can understand why it can survive the tests I have put it through.   

Again, this was a VERY good call on your part.   I doubt I would have bought this meter had you not recommended it.  I wonder if any of the new meters can survive this same amount of punishment.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 04, 2015, 03:55:17 am
From the pictures I have seen of the 101 and 107, they don't look at all the same.   One look at the 101 and you can understand why it can survive the tests I have put it through.
Yep. The 101 obviously has much more input protection. It will be interesting to see if the 107 survives as well as the 101.


Again, this was a VERY good call on your part.   I doubt I would have bought this meter had you not recommended it.
Aw, it was nuthin'  :-[

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 04, 2015, 04:21:12 am
I'm curious to see how the Amprobe holds up because Uni-T is the OEM of that specific model.  (take it apart along-side one of the Uni-T and you'll see a lot of similarities)  I assume Amprobe has them made to order so I'd imagine sufficient input protection is added.  We'll find out soon enough!

It was interesting to see that all of the CEM OEM ones (extech, circuit-test, southwire) all took damage.

How many are left completely unscathed now, seven or so?  They're dropping like flies  :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 04, 2015, 03:26:03 pm
I think you will be very surprised by what has survived.  Of the eighteen I started with only five are unscathed.   Consider the new generator is running about 30% capacity,  I'm sure I can narrow it down. 

I am seeing a lot of what I call 87V damage where they are still usable.   My plan is to run these separately.     

https://www.youtube.com/watch?v=UWClLK587v0 (https://www.youtube.com/watch?v=UWClLK587v0)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 04, 2015, 04:03:31 pm
Second half of the 1.5KV tests.

https://www.youtube.com/watch?v=vIDc91JeuAY (https://www.youtube.com/watch?v=vIDc91JeuAY)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 04, 2015, 07:08:14 pm
Excellent!  I'm rooting for that radioshack one.  You can get it for $25 on ebay/amazon brand new.  If it weren't for its pathetic 100 uF max capacitance range, it would be a really good all around meter WITH true RMS.  I'm actually quite surprised it's gone this far.

I have a feeling that 107 will go the distance like your 101 did.   :popcorn:

 :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on October 04, 2015, 11:25:22 pm
The unpopulated spots on the UT61E make me wonder how the European TUV tested version of the UT61E handles. It has those spots fully populated and has beefed up fuses if I remember correctly.

Sent from my LG-ls990 using Tapatalk

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 05, 2015, 01:49:20 am
joeqsmith:

I am rather impressed at the work and time you have put into these tests. Thank you very much for the time and effort, and cost! These tests certainly are weeding out meters that can't survive normal abuse, and not even abuse in some cases. Like I keep trying to tell people, the UT61E was capable of dying merely from walking around, and your tests kind of demonstrate that.

I am glad you like the BM869S so much and I hope it ends up at the end as one of the survivors.

5ky:

Thanks for throwing your money into the mix to get destroyed. This is a great service to all to learn what really is worth buying.

These tests certainly will demonstrate to people why they should consider spending money on good meters and not junk. From the tests so far, some meters will appear to be working right in some function but will be way off in other ways. This is a dangerous condition.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 05, 2015, 03:16:20 am
Excellent!  I'm rooting for that radioshack one.  You can get it for $25 on ebay/amazon brand new.  If it weren't for its pathetic 100 uF max capacitance range, it would be a really good all around meter WITH true RMS.  I'm actually quite surprised it's gone this far.

I have a feeling that 107 will go the distance like your 101 did.   :popcorn:

 :popcorn:

If I were to pick from the meters you purchased in this group, it would be that one meter that you kept that I said I would not test even if you sent it.   :-DD

The unpopulated spots on the UT61E make me wonder how the European TUV tested version of the UT61E handles. It has those spots fully populated and has beefed up fuses if I remember correctly.

Really??!!

joeqsmith:

I am rather impressed at the work and time you have put into these tests. Thank you very much for the time and effort, and cost! These tests certainly are weeding out meters that can't survive normal abuse, and not even abuse in some cases. Like I keep trying to tell people, the UT61E was capable of dying merely from walking around, and your tests kind of demonstrate that.

I am glad you like the BM869S so much and I hope it ends up at the end as one of the survivors.

5ky:

Thanks for throwing your money into the mix to get destroyed. This is a great service to all to learn what really is worth buying.

These tests certainly will demonstrate to people why they should consider spending money on good meters and not junk. From the tests so far, some meters will appear to be working right in some function but will be way off in other ways. This is a dangerous condition.

I hope that the videos I made showing the generator and talking about the amount of energy I am using were helpful to you and others as well.   

It may have been interesting to have another UNI-T 139C in this mix as well just to see how it would do against the 61s.     

The only bad thing about putting the Brymen through all of these tests is it didn't have an 87V sitting there with it.   However, I do have a way to reproduce these tests now and have everything documented as to what I did.  So, nothing says that if an 87V happens to show up that it wouldn't get some special treatment.    :-DD

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 05, 2015, 09:36:17 am
I have a feeling that 107 will go the distance like your 101 did.   :popcorn:
The 101 appears to have more input protection:

https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/ (https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/)

https://www.eevblog.com/forum/testgear/review-first-impression-of-the-fluke-107-multimeter/ (https://www.eevblog.com/forum/testgear/review-first-impression-of-the-fluke-107-multimeter/)

Most of the big components look identical but the 101 has an extra chain of seven resistors on the input. I can't see that in the 107.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=174497;image)


I'm in the camp that damaged meter is a as-good-as-dead meter. If you know for a fact that some of the ranges are broken then how far can you trust the other ranges?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 05, 2015, 10:04:54 am
That chain forms the 10MOhm impedance on the voltage range.
7x 1.433MOhm precision resistor. The 107 must have it too, probably on the other side of the PCB.
Protection is the same on both (1 fusible resistor, 1 PTC and 2 MOVs). 101 may have an advantage on wider trace separation.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 05, 2015, 10:15:44 am
That chain forms the 10MOhm impedance on the voltage range.
7x 1.433MOhm precision resistor. The 107 must have it too, probably on the other side of the PCB.

Yep, I wondered if it has it them the other side of the PCB...can't find a photo though. Anybody have one they can open up and take a peek?


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 05, 2015, 01:12:55 pm
I'm in the camp that damaged meter is a as-good-as-dead meter. If you know for a fact that some of the ranges are broken then how far can you trust the other ranges?

I'm not following--did the 107 already take damage or something?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 05, 2015, 01:19:20 pm
That chain forms the 10MOhm impedance on the voltage range.
7x 1.433MOhm precision resistor. The 107 must have it too, probably on the other side of the PCB.

Yep, I wondered if it has it them the other side of the PCB...can't find a photo though. Anybody have one they can open up and take a peek?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 05, 2015, 01:23:27 pm
I'm in the camp that damaged meter is a as-good-as-dead meter. If you know for a fact that some of the ranges are broken then how far can you trust the other ranges?

I'm not following--did the 107 already take damage or something?

No...just talking in general about the half-dead ones.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 05, 2015, 01:38:27 pm
The 107 must have it too, probably on the other side of the PCB.
Yep, I wondered if it has it them the other side of the PCB...can't find a photo though.
...pic of 107
:-+

OK, so the 107 is going to survive as well! We'll have a joint winner!!

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 05, 2015, 04:12:49 pm
Yeah, I concur.  Injured is as good as dead.

That being said, is there a difference between keeping the user safe and dying in the process, versus keeping the user safe AND surviving the incident?  I feel like one is safety, and the other is safety AND robustness. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 05, 2015, 05:13:38 pm
I would prefer that if a meter is going to fail, it fails completely and is obvious that it has failed. A situation where the meter still appears to work on some function but shows incorrect values on another or another range is just asking for someone to get hurt or for damage to occur. This is why it is always a good idea to have two reliable meters, and check them against each other regularly. If you are going to measure something potentially hazardous then you should always cross check before trusting the reading.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 05, 2015, 11:43:25 pm
Very few of the meters tested have failed 100% when they were damaged.   I am looking at seven of them now that have one or more features that still work correctly (but I doubt for much longer). 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 06, 2015, 12:46:40 am
I stand corrected.  There are only three meters with partial damage...  >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 06, 2015, 01:42:28 am
I stand corrected.  There are only three meters with partial damage...  >:D
I'm very sure you will fix that.  >:D
 :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 06, 2015, 04:35:42 am
I put together the next video showing the meters being ran at 2KV, 100us FWHH, 1us rise, 2 ohm source.   

https://www.youtube.com/watch?v=4gJ161tTBiI&feature=youtu.be (https://www.youtube.com/watch?v=4gJ161tTBiI&feature=youtu.be)


While the UNI-T UT90A was damaged during testing,  I pulled it apart and found my repaired trace was damaged but no other parts were taken out.  I repaired this area again.  Being it is the only meter that I has played Van Halen's Eruption, I figured I owed it one last life.   
     



Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 07, 2015, 12:45:14 am
The 87V clones are tested at 2.5KV.   

https://www.youtube.com/watch?v=1uIA6KIuH0k (https://www.youtube.com/watch?v=1uIA6KIuH0k)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 07, 2015, 01:16:43 am
The remaining working meters are tested at 2.5KV 100us FWHH 1us rise 2 ohm source.   

https://www.youtube.com/watch?v=friMJg9E7MY (https://www.youtube.com/watch?v=friMJg9E7MY)

The next video will show testing at 3 and 4KV.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 07, 2015, 05:00:19 pm
3 and 4KV testing...

This video is VERY long and there is not a lot of action (none).  You have been warned.

https://www.youtube.com/watch?v=mgwmCG9z9zw (https://www.youtube.com/watch?v=mgwmCG9z9zw)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 07, 2015, 09:50:13 pm
The damaged meters are ran at 4KV...

https://www.youtube.com/watch?v=bT1a3LaKCkI&feature=youtu.be (https://www.youtube.com/watch?v=bT1a3LaKCkI&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on October 07, 2015, 10:29:04 pm
That was entertaining.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 07, 2015, 11:18:34 pm
That was entertaining.

I tried to make up for what could very well be the most boring YouTube video ever created.   :-DD   

I knew if I didn't post that test data, someone would ask about why I skipped over it.   For those who have not watched that long 45 minutes of nothingness, skip to the last 2 minutes and you will know all you need to or just watch the last video.

Next up, 5KV.      5ky asked I return any of the working meters when I was done.  I am trying my best to save on shipping costs!

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 07, 2015, 11:28:34 pm
5ky asked I return any of the working meters when I was done.  I am trying my best to save on shipping costs!
:-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 08, 2015, 02:46:03 am
The new generator is running full tilt tonight.  All the stops are off.   This test will be much harder for the meters to survive than the transient used during the finals between the Fluke 101 and the AMPROBE AM-510.    IMO, any meter that passes this is pretty robust.   

If anything does survive, that meter/s will then be ran on the original generator.  Only one meter has survived on that test fixture and that's the Fluke 101.  Even Fluke's own 87V could not survive that test.   

....

First meter has been tested and actually PASSED!!!!  We have at least one meter that has a chance to take on the 13KV waveform!!!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on October 08, 2015, 03:14:16 am
Looking forward to a possible video.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 08, 2015, 05:06:30 pm
I expect to make three more videos.   One for 5KV, one for 6KV and then the finals using the original transient generator.   

With the Fluke 101 need to share the spotlight?  Will it just be the two Flukes or does the 101 really only pass because of it's lack of a current input?    Many have asked why buy a Fluke if others are just as good.   We know Flukes own 87V could not survive the final test.   What will people think if the Radio Shack meter survives what the 87V can't?   And what about the Brymen??   Am I really going to put my own $230 Brymen meter on this generator just to see if it passes a test where the 87V failed?   

 :popcorn:

Get your popcorn and soda's because we are nearing the end....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 08, 2015, 06:56:11 pm
I expect to make three more videos.   One for 5KV, one for 6KV and then the finals using the original transient generator.   
:clap:  >:D

Quote
What will people think if the Radio Shack meter survives what the 87V can't?
:wtf:  :o


Quote
And what about the Brymen??   Am I really going to put my own $230 Brymen meter on this generator just to see if it passes a test where the 87V failed?   
The cost of the Brymen and the Fluke 87V is miniscule compared to the time and effort you have put into this project thus far and because of that I'd be shocked if you didn't give them a taste of the evil lady. >:D

Do it Joe, do it.  :box:
 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: marber on October 08, 2015, 08:54:41 pm
With the Fluke 101 need to share the spotlight?  Will it just be the two Flukes or does the 101 really only pass because of it's lack of a current input?    Many have asked why buy a Fluke if others are just as good.   We know Flukes own 87V could not survive the final test.   What will people think if the Radio Shack meter survives what the 87V can't?   And what about the Brymen??   Am I really going to put my own $230 Brymen meter on this generator just to see if it passes a test where the 87V failed?   

Where is that 87V now anyway? :)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 09, 2015, 03:15:40 am
Where is that 87V now anyway? :)

Where it gets much better care than it ever did in my hands. 

Do it Joe, do it.  :box:

 :-DD   You're not the only one wanting to see this. 


Not to spoil the outcome, I have not run the high voltage test yet but I have ran the AMPROBE AM-530 all the way up to 5.9KV (max output).  Keep in mind that the AM-510 was in the finals with the Fluke 101.  Both companies owned by Danaher so I was not too surprised.   But as I continued to test the 530 at higher voltage levels, it never gave any signs of an arc.    Also, once it was damaged, it never really got any worse like all of the other meters.   It still read DC and AC voltages just fine.   So rather than try and finish it off, I thought it may be more helpful to some of you if I actually attempted to repair it.

I did a quick check and when in ohms, I could see the output was working but the input was loaded.   There is only one part in this node, Q9.   This is an H1A.   I pulled it and sure enough, it was damaged.   Installed a new one and all of the modes appeared to work.   The meter was never all that accurate, so I went ahead and aligned it.   From what I could tell:

VR1 sets the DC offset
VR9 sets the AC
VR6 sets the temperature
VR7 sets the capacitance

So if you happen to over voltage your AMPROBE AM-530 by accident and the ohms, diode and capacitance modes no longer work, check Q9. 


And for the few of you actually following this thread, here is the 5KV testing.  It's long but there is some damage for everyone to enjoy.....

https://www.youtube.com/watch?v=gPAIIqxnRj4 (https://www.youtube.com/watch?v=gPAIIqxnRj4)



Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 09, 2015, 12:19:35 pm
The first of the meters are subjected to the new generator's maximum level.   This included the AMPROBE AM-530.   

https://www.youtube.com/watch?v=mzxH6HHsuLQ&feature=youtu.be (https://www.youtube.com/watch?v=mzxH6HHsuLQ&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 09, 2015, 11:54:37 pm
The computer is compressing the last video and I will upload it tonight.   Then I am all caught up and am free to focus on the final video.   

Sorry for the length of some of these.  I sped things up further in this last video when the actual transients are being applied.   


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 10, 2015, 02:43:05 am
Glad to see fluke and amprobe living up to their names!  I hope Extech gets a new OEM in the near future because their EX series meters are a complete fail.

 :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 10, 2015, 03:55:18 am
For the record, the MM series by Extech are the Brymens.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 10, 2015, 05:07:40 am
For the record, the MM series by Extech are the Brymens.

Indeed.  Aren't there a good 4+ companies that relabel those?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 10, 2015, 03:34:40 pm
Finally, the last video is uploaded and I am all caught up!!  Watch as the Brymen BM869s, RadioShack 2200087 and the Fluke 107 are tested at 6KV, 100us FWHH, 2 ohm source.  Much worse than the AMPROBE AM-510 saw in the finals!     

https://www.youtube.com/watch?v=9MjyoJx2Rnw&feature=youtu.be (https://www.youtube.com/watch?v=9MjyoJx2Rnw&feature=youtu.be)

Next up, we may not be able to answer the question, "If Brymen BM869s is cheaper and as good, why people would still buy Fluke?"   People buy what they buy.   But we can get an idea if the Brymen BM869s can handle high level transients than Fluke's popular 87V.   

Found my original Fluke in a magazine.    $299 or roughly $1445 in today's dollars.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 11, 2015, 05:53:28 am
I might have to pick up one of those Brymens.  They look legit.  The price is what's crazy.  You could almost buy three of those for the price of a Fluke 87V.  Don't get me wrong, I love my 87V, but when you start looking at the list of things the Brymen can accomplish for 1/3 the cost, it's really impressive.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 11, 2015, 07:29:04 am
Which Brymen are you referring to?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 11, 2015, 10:05:12 am
Which Brymen are you referring to?

Whatever the flagship one is. 869s, correct?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 11, 2015, 10:32:35 am
The Fluke 87 V (lifetime warranty) costs 405$ in the US. The Greenlee DM-860A (Brymen 869S) costs 417$. Where do you get a third of the price from?
The Brymen 869S (12 month warranty only) costs 227$ in Europe, plus import duties in the US if any, and postage ($10.00)
A multimeter has an import duty rate of 1.7% into the US (About 5$ in this case).

http://www.alliedelec.com/greenlee-dm-860a/70160647/ (http://www.alliedelec.com/greenlee-dm-860a/70160647/)
http://www.tequipment.net/FlukeDigital87VMultimeter.html (http://www.tequipment.net/FlukeDigital87VMultimeter.html)
http://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/bm869s/ (http://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/bm869s/)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 11, 2015, 04:27:08 pm
I agree a third of the price is not comparing best prices. Usually it is more like 2/3 the price.

FYI a Greenlee DM-860A can be had for much less than $417.
http://www.ebay.com/itm/GREENLEE-DM-860A-DMM-500K-COUNTS-DM-860A-/131599331392?hash=item1ea3ee7040 (http://www.ebay.com/itm/GREENLEE-DM-860A-DMM-500K-COUNTS-DM-860A-/131599331392?hash=item1ea3ee7040)

The BM869S is closer to $250 with shipping included. The only difference is the lifetime warranty with the Greenlee.

Some people think the lifetime warranty with Fluke is worth the money. I am not here to argue about personal preferences as it is pointless. I am only stating facts.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 11, 2015, 05:10:43 pm
eBay is hardly a reliable outlet. 3 meters available.  ::)
Return policy 14 days. Greenlee warranty may not apply.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 11, 2015, 05:31:55 pm
http://www.westwayelectricsupply.com/dm-860a-dmm-500k-counts-dm-860a.html (http://www.westwayelectricsupply.com/dm-860a-dmm-500k-counts-dm-860a.html)
http://www.valuetesters.com/greenlee-dm-860a-digital-multimeter.html (http://www.valuetesters.com/greenlee-dm-860a-digital-multimeter.html)
http://www.globalindustrial.com/p/tools/test-measurement/Metrs-HVAC-R/dm-860a-industrial-digital-multimeter (http://www.globalindustrial.com/p/tools/test-measurement/Metrs-HVAC-R/dm-860a-industrial-digital-multimeter)
 :box:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 11, 2015, 05:53:44 pm
I don't like the Brymen red color. People might think I own a Uni-T or something.   >:(

Greenlee Green is a bit better, but a lot more expensive than Brymen Red. :-//

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 11, 2015, 05:57:16 pm
http://www.westwayelectricsupply.com/dm-860a-dmm-500k-counts-dm-860a.html (http://www.westwayelectricsupply.com/dm-860a-dmm-500k-counts-dm-860a.html)
http://www.valuetesters.com/greenlee-dm-860a-digital-multimeter.html (http://www.valuetesters.com/greenlee-dm-860a-digital-multimeter.html)
http://www.globalindustrial.com/p/tools/test-measurement/Metrs-HVAC-R/dm-860a-industrial-digital-multimeter (http://www.globalindustrial.com/p/tools/test-measurement/Metrs-HVAC-R/dm-860a-industrial-digital-multimeter)
 :box:
1. No stock? $325.00 is a good price, if available.
2. Very low stock $313.00
3. Unknown stock $366.00 ($40 less than the Fluke)

Big price differences between US retailers ($417.00~$313.00). Doesn't make much sense to me.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 11, 2015, 05:58:56 pm
I don't like the Brymen red color. People might think I own a Uni-T or something.   >:(

Greenlee Green is a bit better, but a lot more expensive than Brymen Red. :-//
Lifetime warranty, whatever that means at Greenlee.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 11, 2015, 06:35:04 pm
I don't like the Brymen red color. People might think I own a Uni-T or something.   >:(

Greenlee Green is a bit better, but a lot more expensive than Brymen Red. :-//

 :-DD Multimeters as fashion accessories....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 11, 2015, 06:35:35 pm
Oh, it's come down in price. I remember the 87V being a lot more when I bought mine.  Good to see it drop in price.  Half the price would be more accurate then.

However, if we're talking people in EU or AU getting getting an 87V versus the brymen, I'd say that's probably every bit of 1/3 the price for the brymen.

EDIT: I lied, just found my invoice.  Paid $314.  I bought it with Fluke's leather bag / probe set which was what jacked the entire order's price up.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 13, 2015, 01:19:08 am
The Brymen BM869s from TME was shipped to the USA in under a week for $235 US.   They are in-stock.   When I last looked on Amazon, the 87V was about $412 with shipping.   To be honest, I really was not too concerned about the price.  I knew what I wanted the meter for and what features I wanted.  Even at the same price, I would have picked the BM869s over the 87V.   

So many reviews on the BM869 but no one takes it apart.  Sure, they pop the cover but no one was willing to go further.   :palm:  That won't be a problem.   If I am willing to put 13KV to it, you know I am willing to take it apart.   Stay tuned....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 13, 2015, 02:16:51 am
I was starting to think that you might have touched the business end of your new rig or something because we hadn't heard from you in a couple days  :-DD

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on October 13, 2015, 02:18:28 am
The Brymen BM869s from TME was shipped to the USA in under a week for $235 US.   They are in-stock.   When I last looked on Amazon, the 87V was about $412 with shipping.   To be honest, I really was not too concerned about the price.  I knew what I wanted the meter for and what features I wanted.  Even at the same price, I would have picked the BM869s over the 87V.   

So many reviews on the BM869 but no one takes it apart.  Sure, they pop the cover but no one was willing to go further.   :palm:  That won't be a problem.   If I am willing to put 13KV to it, you know I am willing to take it apart.   Stay tuned....

I actually have one fully written up and proof-reading now. Full teardown and some performance analysis (no 13kV testing though lol), will post it soon Finally, got around to fixing my laptop so I can post it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 13, 2015, 02:43:54 am
The Brymen BM869s from TME was shipped to the USA in under a week for $235 US.   They are in-stock.   When I last looked on Amazon, the 87V was about $412 with shipping.   To be honest, I really was not too concerned about the price.  I knew what I wanted the meter for and what features I wanted.  Even at the same price, I would have picked the BM869s over the 87V.   

So many reviews on the BM869 but no one takes it apart.  Sure, they pop the cover but no one was willing to go further.   :palm:  That won't be a problem.   If I am willing to put 13KV to it, you know I am willing to take it apart.   Stay tuned....

I actually have one fully written up and proof-reading now. Full teardown and some performance analysis (no 13kV testing though lol), will post it soon Finally, got around to fixing my laptop so I can post it.

 :-+ Looking forward to it. 

I was starting to think that you might have touched the business end of your new rig or something because we hadn't heard from you in a couple days  :-DD

Yea, I think you know first hand that 15 meters is a pretty big project to take on.    :-DD  PM'ed you about the meters.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 14, 2015, 04:44:21 am
THE FINALS!!!!    With the RadioShack, Brymen BM869s and Fluke 107 taking on the 13KV generator.    Again, big thanks to 5ky for making this happen!!   

https://www.youtube.com/watch?v=Dchy-0u-W7A&feature=youtu.be (https://www.youtube.com/watch?v=Dchy-0u-W7A&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 14, 2015, 06:18:35 am
Hats off to you Joe.  :-+
What a great series.  :clap:

Your drop test.  :o 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 14, 2015, 06:31:33 am
Awesome!  I loved the supercut of the discharges at the end.

Also, the meters handled the 3 floor drop test better than I thought they would have.  Did any come out without damage outside of scuffs/scratches/cracks?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 14, 2015, 07:47:32 am
You seem full of praise for the Brymen and scorn for the Fluke 87V.
If I understand correctly, they both failed at 13kV on the Ohms range only and were both fixed by replacing a couple of transistors.
Can you explain the reason for the dichotomy?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: poida_pie on October 14, 2015, 10:27:00 am
Joe,
Thanks for doing all this work, showing how to safely test these meters.
After all this, I am now interested in how the Flukes were designed so that they survive the 12kV pulse.
Time to search for teardown photos of the input protection and maybe also schematics...
This is the result of your work: it's made me start thinking and looking for myself about how and why.

Brillant effort
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 14, 2015, 12:59:43 pm
Thanks for doing this. It's been a long slog but a lot of good data was produced.

I might have to get me a Fluke 107...

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 14, 2015, 01:01:51 pm
After all this, I am now interested in how the Flukes were designed so that they survive the 12kV pulse.

I don't think the secret is in the schematic.

A lot of the meters have the same level of protection but the MOVs and PTCs blew apart. The ones inside the Fluke didn't. Higher quality/better rated components in the Flukes...?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 14, 2015, 03:11:29 pm
You seem full of praise for the Brymen and scorn for the Fluke 87V.
If I understand correctly, they both failed at 13kV on the Ohms range only and were both fixed by replacing a couple of transistors.
Can you explain the reason for the dichotomy?
Yes, I was wondering too.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: poida_pie on October 14, 2015, 08:37:17 pm
After all this, I am now interested in how the Flukes were designed so that they survive the 12kV pulse.

I don't think the secret is in the schematic.

A lot of the meters have the same level of protection but the MOVs and PTCs blew apart. The ones inside the Fluke didn't. Higher quality/better rated components in the Flukes...?
Exactly, I wonder what happens to the various MOVs PTCs ect when fed 12kV. It may be a simple gross overload, or possibly something more sinister such as leakage like non ideal behaviour that permits overload into sensitive areas.
It's time for me to learn about MOVs and the other protection device's real properties.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 15, 2015, 07:03:53 am
Thanks for the kind comments.   

Also, the meters handled the 3 floor drop test better than I thought they would have.  Did any come out without damage outside of scuffs/scratches/cracks?
It would be very hard to say just how much damage was done during drop as the meters had all been pretty much destroyed beyond repair by this stage of testing.   There was one meter that it tore an IC off the board during drop.  Many of the LCDs were damaged.    That Circuit-Test was the only somewhat working meter I dropped.  It cracked the kickstand in half but really that meter held up very well which was why I gave it its own little segment.      I really thought the the INNOVA would do nothing in the drop because it is so light but that was not the case.   
 
I might have to get me a Fluke 107...

5ky has offered to allow me to continue to test the Fluke 107.   Don't be too surprised to see in a later video.   The things I did not like about the 101, like the ultra slow continuity test, lack of a backlit LCD were addressed, plus you can measure AC and DC currents.    Still not a very feature rich meter but hard to argue how electrically robust it is.   

After all this, I am now interested in how the Flukes were designed so that they survive the 12kV pulse.

I don't think the secret is in the schematic.

A lot of the meters have the same level of protection but the MOVs and PTCs blew apart. The ones inside the Fluke didn't. Higher quality/better rated components in the Flukes...?
Exactly, I wonder what happens to the various MOVs PTCs ect when fed 12kV. It may be a simple gross overload, or possibly something more sinister such as leakage like non ideal behaviour that permits overload into sensitive areas.
It's time for me to learn about MOVs and the other protection device's real properties.


Take it for what its worth, I have now put 23 meters to the recycle bins.  It's not a lot of data but worth a high level rundown of the types of failures I have seen from running these tests.   


I would say the highest failures that cause the meters to be non-repairable, the control IC is damaged.  This happens a lot.  To be clear, I am not at all suggesting that the IC is the problem with the designs where they fail. 

Transistors/diodes.    This is been a very common theme.  In these cases, most appear to be setup as a clamp.  In many cases, these parts will blow apart and become an open.  Then the transient will continue to the next part.  Normally the control IC.   In most cases where the IC was damaged, a clamp was damaged too.   Most, but not all.   In some rare cases I suspect the IC was damaged with no other damaged parts. 

PTCs have taken their fair amount of damage.  I most cases, they still work even though they arc over.  The arc will often damage the outside coating assuming it has one.  Parts that do not have this layer just arc around the outside.  Of course, this nice low impedance arc will go to the next thing down the chain, normally the clamp.    In some rare cases the PTCs were damaged beyond the point where they would function.

MOVs  Well, my own experience with MOVs is they degrade and short.  Their cases will catch fire and crack.   For the meter's I have damaged, I have never seen an MOV fail.    This does not surprise me at all nor should it surprise anyone here.   The MOVs used are normally behind a PTC and are going to handle a fair amount of energy.   Again, the amount of energy I am using to test these meters is VERY small.   Enough hits' I would expect to see them degrade.     This again is why I get confused when people talk about correlating these tests with meter safety.  That's just stupid.  There just is not enough stored energy to do anything like explode a meter.   And again, that was never a goal of mine....   Sorry for beating the dead horse, yet again....

Resistors  I was going to post HV resistors but that may confuse a few people.  In several cases, I have seen the front end built with 1206s and other small packages.   Some meters will use little MF 1/4 axial parts.   This is not always a problem but there was a meter in this last set of tests that used 1 pc of a 1/4 MF resistor in series with a PTC then to a MOV.    :palm:    Worse, I think that meter had footprints for some HV parts!!   Again, everyone wanting to make their profits.   Like the Brymen, this particular meter had two different circuits, each with their own single 1/4 MF resistor, going to the Vin jack.   Both of those resistors opened up. 

Circuit boards   There are two things I see happen.  Traces will not handle the surge and become damaged.   In some cases, this has caused even more damage to other circuits once they open up.    The other problem has been lack of creepage distance. 

Other  Let's stop using lead in solder again  :palm:   Here's an idea, make reliable products that don't end up in land fills!   I have seen more than one solder joint fracture.   Some are just poor hand soldering.    Normally, problems like this I just fix and move on with the testing.   That said, most of these are now lead free and look good.   Time will tell how this plays out.

So I stated in the video that I thought it would not take a whole lot to get the Brymen to pass that last test.  While the Brymen BM869s was damaged, the two transistors still sort of worked.  In most cases, when the diodes or transistors like this have failed, there was enough going through them to make the damage very visible.  :-DD   Take that Danaher 87V for example.  Three diodes damaged and the transient cracked every case.    As you saw from my video, that Brymen can read in the pf.   So shoving a MOV across the input with 2000pf may not be such a smart idea but in some cases this may not be critical.    I don't think you will find a single one size fits all fix.

If we wanted to talk about safety, I think you need to consider that in some cases what I wrote about the failures may have been by design to prevent a hazard.   Take for example the meter that I mentioned from 5ky that had the two 1/4W MF parts.   Sure I bitched about the pads allowing for a larger package.  However, that fact that they opened my have been by design to prevent a hazard.     :-//   I don't know, nor do I care as I have no interest in using a meter like this in a high voltage high energy applications.    I am interested in a meter that is robust as well as feature rich.   The Brymen BM869s is the best I have seen for my use.   

Sorry for the long post.  Hope it helps tie things together.   


You seem full of praise for the Brymen and scorn for the Fluke 87V.
If I understand correctly, they both failed at 13kV on the Ohms range only and were both fixed by replacing a couple of transistors.
Can you explain the reason for the dichotomy?
Yes, I was wondering too.

Fluke, what can I say that has not already been written in the history of Fluke and Danaher. 

"At Danaher, our vision is that associates and customers will demonstrate extraordinary loyalty; that we will be respected and admired by all who come into contact with us;...."

I admire the way the $400+ 87V is tested in your labs but blew the backs off of three diodes during a test that your $50 meter withstood!  A $50 meter that you do not even mention on your US website nor offer in the US.    Good Job Danaher, you have my respect!!    And really, isn't the fact that I have taken the opportunity to post videos about my very first digital meter that I have kept over three decades, demonstrate my extraordinary loyalty to the brand?     You have placed yourself on a pedestal for all to admire.   

Brymen, what can I say.  I am impressed with your website!   :palm:   I know you wrote that the BM869s would not survive my 6KV hit by design,  but you were willing to back me up and push ahead.   When the BM869s was damaged, did you back out knowing very well I had just hit the meter with far more than it was ever designed to handle?   No, you held up your end.   And when I offered to have a look at the meter to see what had happened, did you say that would void the deal.  No, you hung right in there.    That is trust!  You are an engineering company for engineers not some princess on a pedestal!  I have no doubt reading the history of your company where you are heading.   

If I wanted to buy a Danaher/Tektronix scope to put on a pedestal I would but I am surrounded by old LeCroy scopes for a reason!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 15, 2015, 07:16:54 am
Hard to argue with that Joe.

Companies that will stand behind the user are few these days.  |O
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 15, 2015, 12:06:00 pm
I might have to get me a Fluke 107...

5ky has offered to allow me to continue to test the Fluke 107.   Don't be too surprised to see in a later video.   The things I did not like about the 101, like the ultra slow continuity test, lack of a backlit LCD were addressed, plus you can measure AC and DC currents.    Still not a very feature rich meter but hard to argue how electrically robust it is.   

I like the size. Small is good.

I'm after something small that will fit in my little suitcase along with a bunch of Arduinos and stuff but people will stay say "Oh, a Fluke!"  when I pull it out :-DMM
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 15, 2015, 01:12:19 pm
Seems to me you resent having been snubbed by Fluke for not paying any attention to your multimeter 'killing fields'.
I admire the way the $400+ 87V is tested in your labs but blew the backs off of three diodes during a test that your $50 meter withstood!
That 'test' is of your own invention. It is not required by IEC regulations, who should know a thing or two about multimeter safety. The Fluke and the Brymen only require a set of crowbar transistors to protect that range up to 1000V, not 13kV.
A $50 meter that you do not even mention on your US website nor offer in the US.
A very basic cheap CAT III 600V averaging meter for the Asian market. Surely Fluke has the right to release some meters in specific markets, as they see fit.
Brymen is a smaller company trying to make it big in foreign markets. It is understandable that they would be more receptive to unusual requests coming out of the US.

For the record, I got stellar service from Fluke in China, being invited and escorted to their main office in Shanghai. I was allowed to try out several replacement sets of TL910 electronic test probes, until I was satisfied with their quality.
When I bought a Fluke 101 in Malaysia, I was given a good quality Fluke polo shirt, which was probably worth more than the meter!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 15, 2015, 08:08:44 pm
So Fluke is a big company and Joe didn't get attention for something he thought was important. The tests are well thought out and actually very informative to us and, more importantly, to Joe. It is his criteria for what makes a good company and/or good multimeter. This is what Joe relates and states emphatically.

The Brymen BM869S failed in a similar way to the Fluke 87V. So is it equal to Fluke? It doesn't mean that necessarily. It means that with Joe's tests, and in this case it failed in a similar way. Joe had more help and response from Brymen. It is reasonable to feel that a company is more interested in the customer when they respond and support the customer. This is not just Joe's experience, but also that of Wytnucls with Fluke in China. Does this make the experiences equal? No. Does this make them both invalid? No. They are data points to be considered.

Joe prefers the BM869S over the Fluke 87V for his reasons and from his experiences. He has stated his reasons clearly and without obfuscation. Some people will prefer Fluke over anything else based solely on their history and reputation. No problem with that.

Should you select a multimeter based solely on the tests of Joe and nothing else? That is up to you but Joe has his criteria and you might have your's that are in conflict. That is what choice is about. It is ironic that one of the cheapest meters from the models available from one of the most respected brands in the world bested the highest regarded model in these tests.


Many thanks Joe and 5KY for your contribution to our knowledge.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 15, 2015, 08:44:12 pm
I wouldn't dream of using my Fluke 101 on anything above CAT III 600V as per its highest rating, confirmed by a CSA safety listing.
I would have no qualms using a Fluke 87 V in a CAT III 1000V environment.
Nothing I have seen in these high voltage tests is going to change that position.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 15, 2015, 10:11:08 pm
So would you use a CATIV/1000V rated meter, tested and confirmed by UL, over a CATIII/1000V meter, confirmed again, in a high energy situation?  :box:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 15, 2015, 10:41:31 pm
Not particularly. In a CAT III situation, any properly rated meter for that environment would be fine. The Fluke 101 too, if not more than 600V.
If I need autohold, the Fluke 87 or the Gossen 26S, if in a cramped space, the 101.
When did you last work in a CAT IV 1000V environment?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 16, 2015, 01:09:58 am

I like the size. Small is good.

I'm after something small that will fit in my little suitcase along with a bunch of Arduinos and stuff but people will stay say "Oh, a Fluke!"  when I pull it out :-DMM


It's not too much larger than the 101.     I have often wondered just how much the 101 could take.   These are some very impressive meters!


I hope I made it clear that I have never asked for anything free from any of these companies.   I have provided them with the opportunity to be involved with the testing I have done.   It's no hair off my back if they take me up on it or not.    I have only reached out to three companies about these tests.   Obviously both Fluke and Brymen were included.   From the beginning, I stated I would be running the survivor of the low cost meters against some high cost meter to see how they compare.    When we look at Brymen, the cost was $240.  No where near the $410 for the Fluke 87V.  A fair amount of money for what I would pay for a meter.   So it's good to see where these companies stand on their warranties.     In the case of both Fluke and Brymen, I disclosed my intent and wanted to know if they felt their product would survive and if they would warranty them if damaged during the test.     That's it.     

Fluke not wanting to answer these questions is not that big a deal as obviously I went ahead and ran the tests anyway because I wanted to know the outcome.   

I have been clear about the goal for the tests from the beginning.   Nothing there has changed.   

The one thing that the Fluke fan boys are always going to hang their hat on is the fact that the 87V failed at 13KV.   No matter how I attempt to explain that the 87V was only tested at 13KV and I have no idea where it really would fail is ignored by the fan boys.    I had actually thought about blowing up some other cheapo meter at 13KV in the final video and just say "there Brand X didn't fail until 13KV, just like the 87V".   But there was already too much time invested (and it was not going to clear this matter up)

So, for the Fluke fan boys, you want to know just where the 87V fails?   The intent of building a programmable generator like the new one was to answer just this question!   

So get your popcorn out and get ready for the clash of the titans as the Fluke 87V takes on the Brymen BM869s.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 08:51:15 am
The crowbar transistor circuit on the Ohms range isn't meant to survive any voltage above 1000V. If you showed that it failed below that level, then that would be interesting!
Many cheap meters don't have such a circuit and instead, rely on the MOV/PTC for sole protection.

Brymen fan boys always brag about the low price, never about the 1 year only warranty. If the meters are so good, why don't you talk to your pals over there and find out why they don't offer a lifetime warranty? Now that would be interesting!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 16, 2015, 10:06:48 am
The crowbar transistor circuit on the Ohms range isn't meant to survive any voltage above 1000V.

Why not? :-//

I'd expect a Fluke to survive intact up to it's marked rating, not need to be sent off for repair. Isn't that the main reason I'm paying $400 for a meter with less functionality than competitors at half the price?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 10:34:53 am
Well, its marked rating is 1000V. High voltage transients on the Ohms range are extremely unlikely, unless done on purpose and no circuit protection is required under IEC 61010 above that, except for the blanket 'no harm to the user'.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 16, 2015, 11:07:21 am
Well, its marked rating is 1000V.
But as you know, "CAT III 1000V" rating requires an 8000V transient.

http://www.ni.com/white-paper/5019/en/ (http://www.ni.com/white-paper/5019/en/)

I'm sure this is deliberate design by Fluke but it seems disappointing that their flagship meter is designed like that. Voltages over 1000V aren't that unusual, even in hobby work.

no circuit protection is required under IEC 61010 above that, except for the blanket 'no harm to the user'.

But...aren't we always saying Fluke are expensive because they're above the very basic requirements.  :-//

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 16, 2015, 11:39:21 am
Fluke was not willing to provide details on what would be considered abuse and would never give me an answer if they would warranty the 87V if it failed during my tests.   That's their lifetime warranty.     Brymen with their 1 year warranty stated they felt the meter would not survive the 6KV test but they would warranty it anyway, taking part of the risk.    One looks good on paper, the other good in practice.   

To be clear, Brymen has never provided me with any products for free or for evaluation.   

I for one was very interested in seeing how this test would go, so I ran it last night.   If I sound tired in the video, that's the reason.  Without further delay....

https://www.youtube.com/watch?v=x2Dg1QA71wU&feature=youtu.be (https://www.youtube.com/watch?v=x2Dg1QA71wU&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 12:44:36 pm
Well, its marked rating is 1000V.
But as you know, "CAT III 1000V" rating requires an 8000V transient.

http://www.ni.com/white-paper/5019/en/ (http://www.ni.com/white-paper/5019/en/)

I'm sure this is deliberate design by Fluke but it seems disappointing that their flagship meter is designed like that. Voltages over 1000V aren't that unusual, even in hobby work.
.
no circuit protection is required under IEC 61010 above that, except for the blanket 'no harm to the user'.

But...aren't we always saying Fluke are expensive because they're above the very basic requirements.  :-//
You said that, not Fluke. There is no point protecting a meter against imaginary threats, pushing up the price and bulk of a meter. Besides, IEC would have come up with more stringent recommendations, if they felt it was necessary, like they do, once in a while.

8000V transients have been applied to the meter, with no threat to the user, as the UL, CSA and other listings confirm.
Voltages above 1000V are another ballgame and are not covered by the IEC low voltage regulations.

Do not apply more than the rated
voltage, as marked on the Meter,
between the terminals or between any
terminal and earth ground.


Measuring Resistance
Caution:
To avoid possible damage to the Meter or to
the equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before measuring resistance.


Measuring Capacitance
Caution:
To avoid possible damage to the Meter or to
the equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before measuring capacitance.
Use the dc voltage function to confirm that
the capacitor is discharged.


Specifications:
Maximum Voltage between any Terminal and Earth Ground: 1000 V rms
Overload protection mV, Ohm, Diode ranges: 1000V rms


The warranty does not cover damage from neglect, misuse, contamination, alteration, accident or abnormal conditions of operation or handling, including failures caused by use outside of the product’s specifications
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 16, 2015, 06:13:56 pm
Brymen fan boys always brag about the low price, never about the 1 year only warranty. If the meters are so good, why don't you talk to your pals over there and find out why they don't offer a lifetime warranty? Now that would be interesting!

From Merriam Webster:
"Definition of FANBOY
:  a boy or man who is an extremely or overly enthusiastic fan of someone or something "

others
http://www.urbandictionary.com/define.php?term=fanboy (http://www.urbandictionary.com/define.php?term=fanboy)
https://en.wiktionary.org/wiki/fanboy (https://en.wiktionary.org/wiki/fanboy)

I guess then that there are UT71D fanboys, Vici 99 fanboys, Fluke fanboys. Hard to tell what really counts if insults start flying.

A warranty is only as good as the manufacturer's intent to back it up. A warranty is one part of the buying decision equation. How it is weighted in that decision is up to the individual and his personal criteria. Is it more important than dual temperature function? Probably the answer is "yes" to many people. Is it more important than 50,000 count?  :-// Would I prefer a lifetime warranty in addition to every function I would want. Of course! Hmm, it is offered by another brand name but is it worth the extra money?  :-//
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 06:43:55 pm
Greenlee new 1 year lifetime warranty:  ::)

http://www.greenlee.com/support/warranty.html (http://www.greenlee.com/support/warranty.html)

(http://greenlee.ebizcdn.com/5f11b27f131494a1c014fcced2f13165)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: mtdoc on October 16, 2015, 06:50:11 pm
Any test engineer or working scientist knows that you can't draw any meaningful conclusion from testing with an n=1 (or 2) - so all this teeth gnashing about exactly what these tests ultimately prove is misplaced IMHO.  They are certainly interesting and entertaining and make for a good discussion. I say well done Joe! (even though I know he has not tolerated my critique in the past).  Joe's biases come through but that is not a criticism - we all have our biases.  Any strongly held opinions about the  87V based on these tests are unfounded IMO but that's ok - we all have opinions..

As far as Fanboyism.  My favorite and most used meter is my Brymen 257.  I have stated this several times on this forum and it's the meter I continue to recommend to others here as well.    I own several meters of various brands including a Fluke 87V (bought for $200 on eBay).    That said if I was in the market for a full featured high resolution multimeter, I would buy a Brymen 869 simply because on a bang/buck basis it far outshines the overpriced 87V IMO.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 16, 2015, 08:45:29 pm
Greenlee new 1 year lifetime warranty:  ::)

http://www.greenlee.com/support/warranty.html (http://www.greenlee.com/support/warranty.html)

(http://greenlee.ebizcdn.com/5f11b27f131494a1c014fcced2f13165)

If you are going to insult people and try to prove them wrong, at least find the right information instead of just that which appears to support your point of view:
http://www.greenlee.com/products/DMM-500K-COUNTS-(DM%2540d860A).html?product_id=19551 (http://www.greenlee.com/products/DMM-500K-COUNTS-(DM%2540d860A).html?product_id=19551)

It clearly states for that product, that it has a lifetime warranty.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 16, 2015, 09:14:38 pm
Joe:

I was sincerely surprised to see the 87V fail on the ohms at 1.5kV. Was this the one that you repaired or a new one? This does not remove my confidence in Fluke in any way, but it was a surprise. It is not likely a test condition that the vast majority of people will come across so I don't see it as any negative against the 87V. A person making this error in real life tests should be to blame and maybe shouldn't be working with a multimeter unsupervised.

The fact that the BM869S failed at a higher voltage doesn't mean much neither. I would suspect variation in component manufacturer could have as much to do with the difference as the circuit design.

What was nice to see in both cases is that they were so easily reparable for so little expense.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 09:24:14 pm
in·sult
speak to or treat with disrespect or scornful abuse.
synonyms: abuse, be rude to, slight, disparage, discredit, libel, slander, malign, defame, denigrate, cast aspersions on, call someone names, put someone down.

I don't know why you feel insulted. I referred everybody to a new Greenlee warranty of 12 months for all their products . Maybe I should feel insulted for being wrongly accused of insulting people.
A limited lifetime warranty can be anything the manufacturer wants it to be, even 12 months.
If you have tangible information that the limited lifetime warranty for the Greenlee meters is longer, I'd be glad to modify my previous post with the exact number of years. I don't have a point of view. I'm only interested in facts.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 16, 2015, 09:29:25 pm
Joe:

I was sincerely surprised to see the 87V fail on the ohms at 1.5kV. Was this the one that you repaired or a new one? This does not remove my confidence in Fluke in any way, but it was a surprise. It is not likely a test condition that the vast majority of people will come across so I don't see it as any negative against the 87V. A person making this error in real life tests should be to blame and maybe shouldn't be working with a multimeter unsupervised.

The fact that the BM869S failed at a higher voltage doesn't mean much neither. I would suspect variation in component manufacturer could have as much to do with the difference as the circuit design.

What was nice to see in both cases is that they were so easily reparable for so little expense.
Rubbish.

The Fluke (and argueably the Brymen also) is just not robust enough.......do some power electronics with contactors or large inductors and subject a meter to back EMF and poof.  :wtf:

Robust protection of a meter for this work is REQUIRED.
For entry level meters to survive and flagship models not.  :wtf:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 16, 2015, 10:13:31 pm
No, the meters did not fail in an unsafe manner. The tests that Joe did couldn't even show that. Both Fluke and Brymen meet the safety requirements as spelled out by the IEC for their CAT ratings.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 16, 2015, 10:28:50 pm
No, the meters did not fail in an unsafe manner. The tests that Joe did couldn't even show that. Both Fluke and Brymen meet the safety requirements as spelled out by the IEC for their CAT ratings.
I agree of course, but Joes tests were never about meter safety, only meter robustness.

That is, will a meter likely fail in real world usage with the transients that Joe defines.
Are those transient levels unreasonable? I don't think so.
Maybe some of the meters were never designed for use in such environments, only bench electronics.  :-\ Wouldn't we expect price to reflect the robustness of meters, we do but Joes tests show this thinking to be fatally flawed.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 16, 2015, 10:49:59 pm
The Fluke (and argueably the Brymen also) is just not robust enough.......do some power electronics with contactors or large inductors and subject a meter to back EMF and poof.  :wtf:
Yep. I was messing about with some little Neon lamps the other day and when there's no load on my little 5V->150V transformer the output goes over 1000V, no problem.

(As measured with a $5 meter set to 1000V mode. It survived the spark...)

Yes, you have to set the Fluke 87V to Ohms mode to kill it that way, but still...not good.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 16, 2015, 10:53:41 pm
I hope Fluke is watching this thread...  :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 10:59:06 pm
Use a high voltage probe when voltages above 1000V are likely to be encountered (Overvoltage Category I only).

40,000V DC 28,000V AC
Division ratio 1,000:1
60$

(http://www.elexp.biz/test/hvp40.jpg)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 16, 2015, 11:05:36 pm
I hope Fluke is watching this thread...  :popcorn:
Does it matter?

What matters is, are there mid priced meters out there that ARE electrically robust and WHO will donate them to Joe for further tests?

Daves EEVblog DMM's?

Where's my popcorn?  ;D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 16, 2015, 11:13:51 pm
Use a high voltage probe when voltages above 1000V are likely to be encountered.
+1
But how do the inexperienced know when to do this?

We've all made DMM range selection errors and subjected our meters to all sorts of abuse, sometimes it is just supidity, other times unexpected voltages. That the meter should protect you as per CAT or IEC ratings is a given, but simple user errors should not result in a  :-BROKE  :-DMM
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 16, 2015, 11:30:55 pm
There are usually plenty of warning labels on appliances with high voltages inside.
I don't have to tell you that electricity is dangerous and a fair amount of knowledge is required to avoid accidents.
Multimeters are not entirely foolproof and should be used with a minimum of caution.
For what it's worth, I can't think of any high-end meter that has an overvoltage protection above 1000V on the Ohms range. And I've read a lot of manuals to compile the multimeter lists.

This is what Gossen says about their multimeters:
Be absolutely certain that the measuring ranges are not overloaded beyond their allowable capacities.
Limit values are included in the overload capacity table (600V for the Ultra, with a 10 second limit)


Agilent's overload protection on the Ohm range (U1271):
1000 Vrms for short circuits with <0.3 A current.

Amprobe overload protection on the Ohm range (HD160C):
Overload protection, all ranges: 1500 V dc or 1000 V ac rms
Transient protection on voltage ranges only:
12 kV impulse (1.2 uS/50 uS) based on EN 61010-1:2001 impulse requirement for at CAT IV 1000 V/1500V dc product.
This product should not be used in installations where transients exceed 12 kV.

 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 17, 2015, 04:01:07 am
in·sult
speak to or treat with disrespect or scornful abuse.
synonyms: abuse, be rude to, slight, disparage, discredit, libel, slander, malign, defame, denigrate, cast aspersions on, call someone names, put someone down.

I don't know why you feel insulted. I referred everybody to a new Greenlee warranty of 12 months for all their products . Maybe I should feel insulted for being wrongly accused of insulting people.

Sorry for the delay in answering, but I wanted some time to think about what you said. I wanted to think if there was another way you were approaching this other than an attack against me, or Brymen, or Joe, or whatever.

Well you did say there are "Brymen fan boys" in an earlier post. That is an insult, I don't know who you were directing it at, but it IS an insult according to the definition you posted. How can you be insulted for doing what you have proven to have done by your own definition that you have provided?

A limited lifetime warranty can be anything the manufacturer wants it to be, even 12 months.
If you have tangible information that the limited lifetime warranty for the Greenlee meters is longer, I'd be glad to modify my previous post with the exact number of years. I don't have a point of view. I'm only interested in facts.

I am also interested in facts. If I insult someone or post information that is incorrect I expect to jumped on. I also post opinions and try to make it clear they are opinions instead of facts. I don't claim to be only interested in facts. People's opinions are also interesting. Are you claiming you don't post opinions?  :-DD

So you then admit that Fluke's lifetime warranty is only what Fluke wants it to be, or are they a special case? I only have the word of Fluke and Greenlee that their warranty is lifetime. Do you have special information? Discount the warranty of Greenlee at the expense of Fluke's. Do you have proof that Greenlee does not honor their warranty and everyone who has had a Fluke has always had their meter fixed without problems or exceptions? I remember evidence on this forum that Fluke decides what is a warranty issue or not even if the fault is obviously not that of the customer's. The 289 supercap corrosion problems are one example. I think I sided with Fluke on that issue but I think they could have handled it better. I remember there are other examples but I can't remember exactly what threads mention them at this point.

I really don't understand why you attack those who think that Brymen is a better buy for them. Do you have a vendetta? You have attacked me for having a bad experience with Uni-T, my experience with Brymen, and now attack Joe for having a well articulated position in favor of Brymen. He has his reasons and has spelled them out.

Amprobe (same parent company as Fluke) uses Brymen for some of its meters, as does Extech, as does Greenlee, as does some others.

You seem to find fault with anything Brymen. Why? Please explain how the legal wording in the warranty of Fluke is superior to Greenlee. Please explain how Brymen has ever let down its customers, show examples. If you read the manuals of everything that you have put in your spreadsheet, then you would have seen the warranty for Greenlee.

"Lifetime Limited Warranty
Greenlee Textron Inc. warrants to the original purchaser of these goods for use that these
products
will be free from defects in workmanship and material for their useful life, excepting normal wear and
abuse. This warranty is subject to the same terms and conditions (my emphasis)  contained in Greenlee Textron Inc.’s
standard one-year limited warranty.
For all Test Instrument repairs, contact Customer Service at 800-435-0786 and request a Return
Authorization.
For items not covered under warranty (such as items dropped, abused, etc.), a repair cost quote is
available upon request"

The conditions being, in bold:

"Goods manufactured by Greenlee Textron will be free from defects in workmanship and material for a period of one year from the date of user purchase, provided such goods are installed, operated, used and maintained in accordance with Greenlee's written instructions."
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 17, 2015, 08:42:33 am
I wanted to think if there was another way you were approaching this other than an attack against me, or Brymen, or Joe, or whatever.
Well you did say there are "Brymen fan boys" in an earlier post. That is an insult, I don't know who you were directing it at, but it IS an insult according to the definition you posted. How can you be insulted for doing what you have proven to have done by your own definition that you have provided?


Mmm....strong accusations on very weak evidence. Don't you have better things to do? I have never attacked Joe or yourself personally in any way. As for Brymen, they make good meters, but they are not perfect and I will point out their weak features, when people just gloss over their shortcomings. AFAIK, Dave's blog still allows free speech and I won't seek your permission before I post anything about Brymen and their products. I just happen to disagree with the way Joe is conducting tests on multimeters and inferring from them that the Fluke 87 is a lesser meter than the Fluke 101.  The term 'Fluke fan boy' (his spelling) was used by Joe in an earlier post than mine (post 496)(1). Did you feel insulted? I didn't think so; it just characterizes people who are passionate about a particular item. Dave himself used the term UNI-T fanboys, referring to people who defend their meters, like myself. If anything, I have a lot of respect for Joe for being able to build a quality high voltage tester at such short notice and for fixing multimeters as fast as I can tie my shoelaces. He certainly didn't convey to me that he felt insulted by anything I said.

(1) 'The one thing that the Fluke fan boys are always going to hang their hat on is the fact that the 87V failed at 13KV.'

So you then admit that Fluke's lifetime warranty is only what Fluke wants it to be, or are they a special case? I only have the word of Fluke and Greenlee that their warranty is lifetime. Do you have special information?

Fluke's lifetime warranty is spelled out unequivocally on the first pages of their manuals:
Each Fluke DMM will be free from defects in material and workmanship for its lifetime. As used herein,
“lifetime” is defined as seven years after Fluke discontinues manufacturing the product, but the warranty period shall be at least ten years from
the date of purchase.
This warranty does not cover fuses, disposable batteries, damage from neglect, misuse, contamination, alteration,
accident or abnormal conditions of operation or handling, including failures caused by use outside of the product’s specifications, or normal
wear and tear of mechanical components. This warranty covers the original purchaser only and is not transferable.

Greenlee should have such a statement to qualify their limited lifetime warranty, but they don't. You haven't found one either, it seems. I take it as being 1 year only, based on their new warranty conditions. If you think it is longer, give them a call and find out.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 17, 2015, 11:14:53 am
Wytnucls:

Fair enough. You are right in that I was being selective on who to call out on the use of "fan boy". It just has been my perception, perhaps wrongly, that you jump on anyone who likes Brymen. I apologize without qualification.

As far as the Greenlee warranty, I did call them. I even made thread about it. They said that lifetime meant lifetime, not one year, "lifetime" as stated in their text. The text I quoted from their website is legally binding and specifically states that it is lifetime for the multimeter using the conditions stated in the one year warranty. This means that the lifetime period is to be substituted for the one year period. The one year warranty is superseded by lifetime by that clause.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 17, 2015, 11:19:33 am
Lifetime by itself doesn't mean anything. It has to be qualified for the product. Is it 5 years, 10 years, 20 years, 50 years after purchase? Is it transferable from one owner to the next?
Word of mouth is not legal, they should refer you to their proper lifetime definition on their multimeter documents.

Gossen warranty: (3 years)
https://www.gossenmetrawatt.com/english/seiten/warrantyconditions.htm (https://www.gossenmetrawatt.com/english/seiten/warrantyconditions.htm)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 17, 2015, 05:54:50 pm
I have never attacked Joe or yourself personally in any way.   .................
The term 'Fluke fan boy' (his spelling) was used by Joe in an earlier post than mine (post 496)(1). Did you feel insulted? I didn't think so; it just characterizes people who are passionate about a particular item. Dave himself used the term UNI-T fanboys, referring to people who defend their meters, like myself.  ................ He certainly didn't convey to me that he felt insulted by anything I said.

It was not my intent to insult anyone with the Fluke fan boy comments and I certainly would not take any comments directed towards Brymen fan boys as an insult towards me.      As you state " characterizes people who are passionate about a particular item" was the intent of the comment.   

Quote
If anything, I have a lot of respect for Joe for being able to build a quality high voltage tester at such short notice and for fixing multimeters as fast as I can tie my shoelaces.

If my trouble shooting abilities make things seem simple, it is only because I have damaged so much stuff over the years!!!    :-DD  But, thanks.   


I treated all brands with equal prejudice (as far as the testing).  Sure I may be biased against Fluke and made that clear from the start but the reality is that all meters are tested the same.   Or at least I attempted to test them all the same.    In the end, twice now I have had to eat crow as I watched yet another Fluke out survive fifteen additional meters.   Even worse, again watching my favorite, shinny new Brymen, that came all the way from Poland,  which cost much more, being damaged in the name of science. 

The Fluke (and argueably the Brymen also) is just not robust enough.......do some power electronics with contactors or large inductors and subject a meter to back EMF and poof.  :wtf:

We've all made DMM range selection errors and subjected our meters to all sorts of abuse, sometimes it is just supidity, other times unexpected voltages. That the meter should protect you as per CAT or IEC ratings is a given, but simple user errors should not result in a  :-BROKE  :-DMM

For entry level meters to survive and flagship models not.  :wtf:

Yep. I was messing about with some little Neon lamps the other day and when there's no load on my little 5V->150V transformer the output goes over 1000V, no problem.

(As measured with a $5 meter set to 1000V mode. It survived the spark...)

Yes, you have to set the Fluke 87V to Ohms mode to kill it that way, but still...not good.

What you both are talking about has everything to do with why I am running these tests.   Watch a review and the meters may be taken apart and plugged into a wall socket at best.  Don't get me wrong, these people doing these reviews provide some very helpful data.   But if I buy a meter I want to know that the thing will survive some basic mistakes.   I would expect for many people, this will not be important.   It's hard to damage a meter looking at digital logic and car electrical system and maybe plugging it into your household wall socket now and then.  Sad that some meters I tested could not even survive this! 
 
Quote
I just happen to disagree with the way Joe is conducting tests on multimeters and inferring from them that the Fluke 87 is a lesser meter than the Fluke 101.

Quote
Any test engineer or working scientist knows that you can't draw any meaningful conclusion from testing with an n=1 (or 2) - so all this teeth gnashing about exactly what these tests ultimately prove is misplaced IMHO.  They are certainly interesting and entertaining and make for a good discussion. I say well done Joe! (even though I know he has not tolerated my critique in the past).  Joe's biases come through but that is not a criticism - we all have our biases.  Any strongly held opinions about the  87V based on these tests are unfounded IMO but that's ok - we all have opinions..

In the first series of meters I mentioned that I had only tested one of each meter and that this was not much of a sample size.  Obviously, we are never going to be looking at large same sizes for any of these reviews.    Many benchmarks are performed with minimal sample sizes and in some cases, even one sample  but it does not mean they are completely invalid or that we can not learn anything from them.   Statisticians are rolling there eyes now..... 

Let me start by saying that these products were obtained through normal channels.  In most cases they were procured through Amazon.   Why does this matter?  Well, if say the manufacture sent me meters directly for these tests, how would we know that these products were not special in some way in order to bias the tests?  So to be clear, in no case did Fluke or Brymen supply me with product for these reviews.   This is what I don't like about regulatory groups.  The companies ship the products to be evaluated.  Many times these may not be the final production parts.   They may need to make some changes and go back and forth a few times before they are certified.    In the end, do we really know the product that was certified is what will be supplied to you and me?  Or, will a MOV be removed to increase profits by some accountant.   Maybe a part was changed out for a cheaper part of what they think is the same quality and the product was not re-certified because of cost, time, etc.     So, because I obtain the meters my some means that the average person could,  I am making some assumption that the meters I test represent the average meter.     

Now this makes for another assumption.  I assume that the manufacturer has their process under control.    They may not and then my first assumption that my one meter represent the mean goes out the window.      So we could say for example, the 87V I tested does not represent the average 87V.  It was some outlier.  Then we also say that Fluke does not have control of their process.    Now I doubt they have a process control problem, but I don't know.  I would more guess that the meter just does not handle the transient by design in these other modes besides voltage.   It's a pretty old design when compared with the 101.  I am sure they have learned a few things and have improved their designs.   I have no data to back that up and am just giving them the benefit of the doubt. 

In the case of the 101 being the only meter to survive my first round of testing, we had a member repeat these tests using a different meter and commercially available transient generator.    The results were the same.   Even at 12KV they could not damage the 101.   I went further and increased the FWHH and added 1KV and still could not damage it.    I have some level of confidence that the 101 is very robust.   That said, I was not too surprised that the 107 survived this same test.     

Now had say the Fluke 87V failed at 2KV and the Brymen BM869s at 2.5KV, I would say we are well withing the margin of error of my tests and the meters them selves (what brand of components, date codes, etc).  But this is not at all what happened.   We have one meter living at 6KV and one failing at 1.5KV.    That's a pretty big window.   I bet if I tested 100 pcs of each meter we could find some 87Vs that would live to 1.7KV and some Brymens that fail at 5.5KV.      If the windows were much wider, I would really question their process and quality control. 

The problem in gaining confidence in the tests is that we are no longer talking about low cost meters.   I doubt that our members are going to run out and buy an 87V and BM869s knowing the 87V may be damaged at 1.5KV just to repeat the test and see which is more robust.     

I don't believe I have skewed the results or biased the test towards one brand or another.     Again, take it for what it is worth or feel free to step up to the plate and take a swing.   I am open to what ever tests the group can come up with to help determine which meters are more electrically robust than others.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 17, 2015, 09:28:38 pm
For what it's worth, I can't think of any high-end meter that has an overvoltage protection above 1000V on the Ohms range. And I've read a lot of manuals to compile the multimeter lists.

So...if you're poking around unknown devices (even battery powered ones) it's better to use Flukes cheapest meter instead of their flagship.  :-//

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: 5ky on October 18, 2015, 12:42:51 am
So much salt, and no popcorn!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 18, 2015, 01:57:40 am
Lifetime by itself doesn't mean anything. It has to be qualified for the product. Is it 5 years, 10 years, 20 years, 50 years after purchase? Is it transferable from one owner to the next?
Word of mouth is not legal, they should refer you to their proper lifetime definition on their multimeter documents.

I agree with you, it is not clear. The definition of "useful life" can be defined as the period over which a capitol purchase is discounted to zero value for the purposes of tax write offs. This still doesn't help much but most companies would write off a multimeter after 5 years. I don't think that this is the definition that Greenlee is using based on my conversation with their service rep.

I am sorry, but the clearest answer I got from Greenlee service is that they will replace almost anything as long as it has failed not by fault of the user. A verbal agreement is as good as a written contract if you can prove the verbal agreement occurred, with a recording for example. I suppose that some boss at Greenlee could say that their employee overstepped his bounds and they will not honor his agreement.

The point is, IMHO, that Greenlee does have a lifetime warranty and it might not be as clear as some others, but the others also have lots of room to deny the claim also as has happened to some here. The room to avoid a warranty claim also exists in the Gossen link you showed. I have no vested interest in Greenlee.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: oldway on October 18, 2015, 07:19:39 am
I have several Fluke multimeters and a 87V.
It is my favourite multimeter but I use it only as a bench meter.
For field service, I am using an old Fluke 73 that I bought in 1993.
There is a good reason for this.

Fluke 87V is far too expensive in Europe (more or less 500€). :--
Even used, it's hard to find one cheaper than 250€

My first 87V has been stolen during field service...It is highly risky because his high value. :scared:

If you don't need to have all the features of a 87V, the 101 seems to be a better option for field service.
Another option is the Brymen 869S that is not as well known as the Fluke 87V and is a lot cheaper for the same safety and features.

To be a real winner in Europe, Fluke should sell his 87V at the same price range as the Brymen 869S, I mean between 200 and 250€  :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 18, 2015, 10:34:13 am
Lifetime by itself doesn't mean anything. It has to be qualified for the product. Is it 5 years, 10 years, 20 years, 50 years after purchase? Is it transferable from one owner to the next?
Word of mouth is not legal, they should refer you to their proper lifetime definition on their multimeter documents.

I agree with you, it is not clear. The definition of "useful life" can be defined as the period over which a capitol purchase is discounted to zero value for the purposes of tax write offs. This still doesn't help much but most companies would write off a multimeter after 5 years. I don't think that this is the definition that Greenlee is using based on my conversation with their service rep.

I am sorry, but the clearest answer I got from Greenlee service is that they will replace almost anything as long as it has failed not by fault of the user. A verbal agreement is as good as a written contract if you can prove the verbal agreement occurred, with a recording for example. I suppose that some boss at Greenlee could say that their employee overstepped his bounds and they will not honor his agreement.

The point is, IMHO, that Greenlee does have a lifetime warranty and it might not be as clear as some others, but the others also have lots of room to deny the claim also as has happened to some here. The room to avoid a warranty claim also exists in the Gossen link you showed. I have no vested interest in Greenlee.
This is Brymen's warranty terms. I don't see much difference compared to the limitations of Fluke's or Gossen's limited warranties. I expect Greenlee's warranty will follow the same guidelines. No company will cover the cost of repair for an item that has been misused by the user, unless by prior arrangement or goodwill on their part. (UNI-T fixed my multimeter under their 3-year warranty, even though I had modified it extensively):

LIMITED WARRANTY
BRYMEN warrants to the original product purchaser that each product it manufactures will be free
from defects in material and workmanship under normal use and service within a period of one year
from the date of purchase. BRYMEN's warranty does not apply to accessories, fuses, fusible
resistors, spark gaps, batteries or any product which, in BRYMEN's opinion, has been misused,
altered, neglected, or damaged by accident or abnormal conditions of operation or handling.
To obtain warranty service, contact your nearest BRYMEN authorized agent or send the product,
with proof of purchase and description of the difficulty, postage and insurance prepaid, to BRYMEN
TECHNOLOGY CORPORATION. BRYMEN assumes no risk for damage in transit. BRYMEN will,
at its option, repair or replace the defective product free of charge. However, if BRYMEN
determines that the failure was caused by misused, altered, neglected, or damaged by accident or
abnormal conditions of operation or handling, you will be billed for the repair.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 18, 2015, 03:50:56 pm
So much salt, and no popcorn!

It seems you are not satisfied with the damage I have inflicted on your meters and I would hate to think I had an unhappy customer.   So, last night I tore the old generator apart and rebuilt some of the circuits to handle even higher levels.   Today I will find the limits of your Fluke 107.

That's a 20KV 50us FWHH wave there with about 15J available..   


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 18, 2015, 04:24:13 pm
Today I will find the limits of your Fluke 107.

Are we placing bets...?  :popcorn:

That's a 20KV 50us FWHH wave there with about 15J available..

Does it go up in steps or are we going straight to 20kV?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 18, 2015, 05:05:22 pm
This will be all up to the MOVs (2x K575 13 26 7mm). Should be able to handle 35 Joules @ 8/20uS, clamping at 600V.
Overvoltage protection is set at 600V on voltage only. No mention of protection on other ranges.
Unfortunately, the clamping ability deteriorates with each transient pulse.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 18, 2015, 07:20:38 pm
I hate working with lead free solder.
Then why on earth do you? It's muck.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 18, 2015, 07:31:51 pm
Because everything is built with that crap now, including this 107.   On the bright side, if I have the heat gun out, you know something didn't go so well for 5ky's Fluke. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 18, 2015, 07:37:44 pm
Because everything is built with that crap now, including this 107.   On the bright side, if I have the heat gun out, you know something didn't go so well for 5ky's Fluke.
Oh dear.  :o  :-DD
Your improved evil lady is truly wicked.  >:D

Will the 101 survive and be top of the heap?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 18, 2015, 08:15:56 pm
I don't understand why anyone would use lead free solder for hobby work.  :scared:

I am interested in seeing the new beast at work. I wish I could get parts here easily to build something too. In Chile, the parts supplies are sparse and delivery times from around the world take months.

Upon reflecting on all the testing, I have a couple of comments if I may. (I know, when have I asked permission before? :) )

The Digitek/Tekpower has a space for an MOV. This would have definitely saved the meter from some damage IMHO, but it would not save the user in a real life big fault. It would be across the inputs directly without current limiting and could make a BIG bang if the meter was subjected to a high voltage surge while connected to a CAT III condition. Maybe that is why it was left out. It exists in my DT2843R meters and it would be interesting to see what would happen.

The title of this thread is "Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests." This could mislead people to think that these are proper CATIII surge tests. Joe has already said many times in the thread that this is not the case, but it still remains in the title.

It is still in dispute whether a meter needs to survive and function after the fault conditions as spelled out in the IEC requirements for multimeters, or if they only need to not cause harm to the user when the fault occurs. ( Yes Joe, your tests are not to prove this nor anything other than your criteria for what is a robust meter).

From Joe's tests, no meter can be said to pass or not pass the IEC requirements since we do not know whether the meter needs to still function or only protect the user from harm as mentioned above. It probably can be said that certain meters would certainly fail the IEC requirements from the damage incurred by Joe's tests, which would predict a big flash over.

An lastly, Joe has spent a huge amount of time and some considerable expense to do this testing. 5KY has also spent some real money. They are electronics nerds to be respected! :)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 18, 2015, 08:19:25 pm
Because everything is built with that crap now, including this 107.   On the bright side, if I have the heat gun out, you know something didn't go so well for 5ky's Fluke.

That doesn't mean you need to continue to use lead free. Dilute the lead free with lead containing solder and be done with it!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 19, 2015, 12:52:55 am
Because everything is built with that crap now, including this 107.   On the bright side, if I have the heat gun out, you know something didn't go so well for 5ky's Fluke.
Oh dear.  :o  :-DD
Your improved evil lady is truly wicked.  >:D

Will the 101 survive and be top of the heap?

I doubt I will run the 101 until I find another brand that I feel will outperform it.   One thing is for sure, that Fluke 107 is one tough little meter.  If you are blowing these up on your hobby bench, tell us all about it!    Even if you just blew up your Brymen BM869s, I would like to hear details about what you did.     No need to tell us you damaged your 87V playing on your bench.  :-DD   
 
I don't understand why anyone would use lead free solder for hobby work.  :scared:

That doesn't mean you need to continue to use lead free. Dilute the lead free with lead containing solder and be done with it!

:palm:  No offense but I find how you derive conclusions very fascinating.  :-DD  The next video may help you understand my comment. 

I hope to have it up in a couple of hours.   Poor little Fluke never stood a chance....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 19, 2015, 02:36:15 am
I don't understand why anyone would use lead free solder for hobby work.  :scared:

That doesn't mean you need to continue to use lead free. Dilute the lead free with lead containing solder and be done with it!

:palm:  No offense but I find how you derive conclusions very fascinating.  :-DD  The next video may help you understand my comment. 

I hope to have it up in a couple of hours.   Poor little Fluke never stood a chance....

I meant to quote this:
Quote
Quote from: joeqsmith on Today at 06:06:44 AM

    I hate working with lead free solder.

Then why on earth do you? It's muck.

I only was agreeing with Tautech.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 19, 2015, 03:14:55 am
Most anything now days is some form of lead free.  If you watched my last couple of videos, you may have noticed I will at times use a Weller heat gun.  Some of the lead free solders have a pretty high transition temp that require me to throw heat to the PCB longer than I would like.   This is where my comment came from.   Putting the parts back is no problem but I don't mix lead free and lead solders.  Nor do I mix no clean and rosin.   :blah: :blah: :blah:

But I do damage meters..
5ky's Fluke 107 takes a  hit for science and somehow, I feel real good about watching it die!   
https://www.youtube.com/watch?v=X5GrYPBjSDs (https://www.youtube.com/watch?v=X5GrYPBjSDs)

THIS IS ONE TOUGH METER!!!!! 

Now that I have an idea where the 107 fails, I would love to put a 28 and 298 on the chopping block.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 19, 2015, 04:05:55 am
I would be interested to see a 28IIEX put through these tests, as well as the Amprobe HD160C. Maybe we can come up with a group donation to add more meters to the junk pile.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 19, 2015, 04:56:42 am
I would be interested to see a 28IIEX put through these tests, as well as the Amprobe HD160C. Maybe we can come up with a group donation to add more meters to the junk pile.
+1
Fluke 15B is the meter I'd like to see play with the evil lady.
I can get one to Joe for USD75 and happily pay half.
Any takers?

15B, 17B same internals.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 19, 2015, 08:48:29 am
It is still in dispute whether a meter needs to survive and function after the fault conditions as spelled out in the IEC requirements for multimeters, or if they only need to not cause harm to the user when the fault occurs.
From Joe's tests, no meter can be said to pass or not pass the IEC requirements since we do not know whether the meter needs to still function or only protect the user from harm as mentioned above. It probably can be said that certain meters would certainly fail the IEC requirements from the damage incurred by Joe's tests, which would predict a big flash over.

I suspect that, after reading several manufacturer's operating manuals, meters with a proper CAT rating should still operate correctly after the relevant high voltage transient tests, but applied on voltage ranges only. Other ranges should survive a voltage equal to their highest CAT rating voltage.
The final test may consist of subjecting all ranges to transients also (to check for damage containment), but it is not confirmed yet.
Amps ranges are tested for creepage, with ruptured fuses in place, while double the CAT rating max voltage is applied for 1 minute.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 19, 2015, 09:50:28 am
Fluke 15B is the meter I'd like to see play with the evil lady.
I can get one to Joe for USD75 and happily pay half.
Any takers?

15B, 17B same internals.

I was thinking the same thing (but one of the newer 15B+ and 17B+ versions...)

Also ... one of those old-school Fluke 27s. They're supposed to be pretty tough but I wonder if they'd hold up or not.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 19, 2015, 12:39:04 pm
The Amprobe HD160C won't fare any better. Overvoltage protection 1500Vdc or 1000Vac on all ranges. Transient protection on voltage ranges only:

Transient protection: 12 kV impulse (1.2
uS/50 uS) based on EN 61010-1:2001 impulse
requirement for at CAT IV 1000 V/1500V dc
product. This product should not be used in
installations where transients exceed 12 kV.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 19, 2015, 01:12:48 pm
This is the overload protection layout for the Fluke 87 (Early 1989 model):

For Volt/Ohm/Diode ranges:
2 MOVs 910V (RV1 RV2)
3 current limiting resistors R1(1kOhm 2W fusible opens for high energy signal) R2(909K 2W)  RT1(1.5K PTC goes to high impedance for sustained voltage overload for mVdc/Ohm/Diode)
1 spark gap (E1) 1500V

For Ohm/Diode ranges:
1 voltage clamp circuit: 3 NPN transistors (Q1 Q2 Q6) 2 diodes (CR7 CR8) 1 resistor (R58) 120kOhm
limits the overload current to U4(ADC) to a maximum of 10mA.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=177428;image)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 20, 2015, 06:01:32 am
If people are really interested in testing more meters, maybe we could do a Paypal account or kick start for each meter people want to run.
Paypal would be OK.

Kickstart takes ages and takes a big comission.

We need to know how many people are interested though. Let's have a show of hands...

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on October 20, 2015, 09:16:30 am
Fluke 15B is the meter I'd like to see play with the evil lady.
I can get one to Joe for USD75 and happily pay half.
Any takers?

15B, 17B same internals.

I was thinking the same thing (but one of the newer 15B+ and 17B+ versions...)

Also ... one of those old-school Fluke 27s. They're supposed to be pretty tough but I wonder if they'd hold up or not.
Nobody but Fungus seems to want to play.  :--

But we must ask Joe first if he wants to be inundated with meters to fry.  >:D
 :popcorn:

Joe?


This is the one I had in mind and Fungus, it is the latest plus model:
http://www.aliexpress.com/store/product/Fluke-15B-F15B-Digital-Multimeter-Auto-Manual-Range-AC-DC-1000V-10A-40M-ohm-Capacitance-100uF/917544_1187715988.html (http://www.aliexpress.com/store/product/Fluke-15B-F15B-Digital-Multimeter-Auto-Manual-Range-AC-DC-1000V-10A-40M-ohm-Capacitance-100uF/917544_1187715988.html)
I know this seller and he may want to play along,  :-\ especially if he can link this thread to his products.  :-DMM

If people are really interested in testing more meters, maybe we could do a Paypal account or kick start for each meter people want to run.
Paypal would be OK

We need to know how many people are interested though. Let's have a show of hands...
Paypal fine with me and I'll put some money where my mouth is.  :D

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 20, 2015, 01:30:48 pm
Nobody but Fungus seems to want to play.  :--

Give it a chance...it's only been a few hours.

As a reference: The last video in this series got 64 views.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 20, 2015, 03:02:31 pm
I said I was interested, I kind of started the idea no?

A Fluke 15B+ would be good, as would a UT71D, UT171B, a Keysight, Hioki, Gossen, Yokogawa, and Ideal.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 20, 2015, 05:29:40 pm
Planning to willfully damage a whole bunch of mainly very safe and expensive meters. And this to prove what again? You guys have gone mental.  ::)
Thankfully, not too many takers.

It would be far more useful (and cheaper) for everybody, if meters with suspected bogus CAT ratings, were subjected to transients in accordance with the IEC regulations, to separate acceptable meters from the dangerous ones.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 20, 2015, 09:42:25 pm
Mental?

I think that Joe is not mental, nor was 5KY. I might be.

The point is more data on where a multimeter fails? Maybe to educate and illuminate the differences between protection schemes and how a specific multimeter might be a better buy in the case of error in use? How a bottom of the line multimeter might be better suited to a newbie who could make some mistakes instead of a higher end one? Have we learned nothing from Joe's tests?

Wouldn't it be interesting if a Gossen couldn't take 1000V on the ohms range for example?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 20, 2015, 11:27:21 pm
You stand more chances of getting pregnant than experiencing high transients on the Ohms range. That's why meters aren't built to withstand that abuse. 1000V is the maximum required and, like all Gossen DMMs, have already been tested to comply with their CAT rating.
Multimeter protection is not rocket science. Most high-end multimeters have the same kind of layout. PTC, MOV and crowbar circuit. As expected, they will fail safely eventually, if pushed above their safety rating.
The message to beginners should be to only acquire meters which have been tested by approved independent agencies.
There is no need to muddy the waters with indiscriminate destruction on all ranges.


Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 21, 2015, 03:06:00 am
If you haven't seen it yet, DextersLab2013 posted a video using his new generator.    Looks like it does a nice job on them. 
https://www.youtube.com/watch?v=glzLlPO6CjY (https://www.youtube.com/watch?v=glzLlPO6CjY)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 21, 2015, 04:34:42 am
Planning to willfully damage a whole bunch of mainly very safe and expensive meters. And this to prove what again? You guys have gone mental.  ::)
Maybe...but if it's only a few $$$ then it's entertainment. People go to the cinema every day to watch them wreck nice cars, etc. :popcorn:

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 21, 2015, 04:37:05 am
You stand more chances of getting pregnant than experiencing high transients on the Ohms range.
The protection isn't just there for transients, it's there for when operators make mistakes.

Would you lend somebody your Fluke 87 at an electronics club meeting if you could lend them a 107 instead?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 21, 2015, 05:21:18 am
Well, the mistake is to test resistance on a live circuit, hence the 1000V protection. You may have to wait a few months before you get any transients.
If you play with higher voltages without a high voltage probe, you deserve that Darwin award.
As for the entertainment value, watching grass grow comes to mind. Maybe if you happen to live on the Atacama plateau:

(https://upload.wikimedia.org/wikipedia/commons/b/bb/Atacama_Desert_between_Antofagasta_and_Taltal.jpg)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 21, 2015, 05:51:34 am
OK, Wytnucls, keep baiting. I am going to ignore you from now on. I just thought perhaps we had a different point of view, but you have now proven you are trying to troll me.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 21, 2015, 08:40:02 am
Stop taking everything so seriously Personal information of another member removed by moderator, please "don't do that"!, that was meant as a teasing joke. I'm surprised you reacted that way because my Canadian friends usually have a good sense of humor.
I'm really sad you're going to ignore me. I enjoyed the few multimeter skirmishes we've had so far.
I'll get so bored and lonely now that I might watch a few Gossen DMMs getting blown up.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 21, 2015, 10:16:41 am
Wytnucls,  I have no problems with you trolling this thread. 

It would be far more useful (and cheaper) for everybody, if meters with suspected bogus CAT ratings, were subjected to transients in accordance with the IEC regulations, to separate acceptable meters from the dangerous ones.

But again, while I had thought about using a standard transient generator to run the meters using the standard IEC waveforms,  it was never my intent to validate CAT ratings.   Forget that for now and lets talk about the "and cheaper" comment.   I have a fair amount of experience using outside labs for testing although it has been several years.   What does lab time cost there?   Do you pay by the day, hour, job?    I would also be very interested in how much time you feel it would take to validate one meter to the IEC standards?    It sounds like you have a lot of experience in this area, so please fill us in.


The protection isn't just there for transients, it's there for when operators make mistakes.
...
Would you lend somebody your Fluke 87 at an electronics club meeting if you could lend them a 107 instead?

That 107 is very hardened and I would have no problems at all about giving one to someone as a basic meter.   

I can see from Wytnucls perspective why none of this makes any sense.   If all you are doing with your time besides trolling is looking up specs for meters (paperwork) and putting all of this information into a spreadsheet (more paperwork) , you will never damage a meter.  Safety is still a huge concern for these people as I understand some paper cuts can get infected if not treated.    These people will never make any mistakes in the lab other than maybe forgetting to change their meter's battery.   


I said I was interested, I kind of started the idea no?

A Fluke 15B+ would be good, as would a UT71D, UT171B, a Keysight, Hioki, Gossen, Yokogawa, and Ideal.

Sorry, but I see no point in testing another UNI-T.   None of the four tested survived any where near what the majority of meters tested did.   The only good use I have found for one was this and really, a cheap set of ear buds did much better.  :-DD   
https://www.youtube.com/watch?v=svJXiMMZzcQ   (https://www.youtube.com/watch?v=svJXiMMZzcQ)



Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 21, 2015, 10:54:13 am
The protection isn't just there for transients, it's there for when operators make mistakes.
...
Would you lend somebody your Fluke 87 at an electronics club meeting if you could lend them a 107 instead?

That 107 is very hardened and I would have no problems at all about giving one to someone as a basic meter.   

I also like the fact that there's no 250mA fuse that costs $12+shipping to replace.

Not one person had a working fuse on the 250mA range last time I did a 'bring your multimeter' day at the club.

If they blow the 10A fuse, well ... something else was probably going to blow anyway. The fuse might pay for itself by saving that thing.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 21, 2015, 11:11:06 am
Joe, you're not interested in IEC regulations testing. I get that. Not much fun as meters don't fail so spectacularly under those. If you change your mind, we can discuss it constructively, like I did for a couple of years with Lightages, Dave and others.
By cheaper, I meant acquiring cheaper meters as the expensive ones have a proper CAT rating already. There is no point retesting a Brymen CAT IV 1000V meter which has a UL listing. Your testing wouldn't validate the CAT rating by any means, but offer some valid guidelines for people who can't afford meters with recognized CAT ratings.
I have damaged a couple of meters actually, but that wasn't by playing carelessly with high voltages. I don't pretend to have your level of knowledge and skills, but paper cuts still hurt!
As for trolling, if it means not agreeing with someone publicly, then I guess I am trolling. Live with it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 21, 2015, 11:52:48 am
Actually, I am very interested in IEC regulations testing but not when it comes to handheld meters.     Under those standards the meters would fail much more spectacularly than what I show.    But that's ok,  I understand, between playing with spreadsheets, reading meter specs and trolling all day gives you little time to do anything else.  And that's fine. 

Yea, I figured you had no idea what it took to test a meter under IEC or what the lab costs would be.  Actually, that's too bad as I was hoping to see how they would compare around the world.   Maybe it's something you could research rather than trolling?  This way you can still spend time reading specs and playing with spreadsheets.   

Quote
There is no point retesting a Brymen CAT IV 1000V meter which has a UL listing. Your testing wouldn't validate the CAT rating by any means, but offer some valid guidelines for people who can't afford meters with recognized CAT ratings.

I don't see how anyone would ever draw a conclusion about a meters CAT rating from my testing.   Maybe you could explain this?    Most of my testing is under 10J.  The video from Dexterslab was 250ish?    Again, because you are special, I will repeat myself yet again,  I am just looking for robust meters.     If you have other test interests, you could always step to the plate and take a swing.   Keep in mind that playing with real hardware can be addictive!   :-DD

As for trolling, if it means not agreeing with someone publicly, then I guess I am trolling. Live with it.

I'm surprised you reacted that way because my (fill in the blank) friends usually have a good sense of humor. :-DD  Hang in there.  I can't afford to damage too many more Flukes.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 21, 2015, 12:16:54 pm
OK, Joe, keep baiting. I am going to ignore you from now on. I just thought perhaps we had a different point of view, but you have now proven you are trying to troll me.  :-DD




Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on October 21, 2015, 12:23:00 pm
The protection isn't just there for transients, it's there for when operators make mistakes.
...
Would you lend somebody your Fluke 87 at an electronics club meeting if you could lend them a 107 instead?

That 107 is very hardened and I would have no problems at all about giving one to someone as a basic meter.   

I also like the fact that there's no 250mA fuse that costs $12+shipping to replace.

Not one person had a working fuse on the 250mA range last time I did a 'bring your multimeter' day at the club.

If they blow the 10A fuse, well ... something else was probably going to blow anyway. The fuse might pay for itself by saving that thing.

It is useful. Some meters have a polyswitch instead to protect the mA range. The 107 doesn't seem to have one. Just as well, as they tend to fail if subjected to high voltages.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 21, 2015, 12:30:53 pm
OK, Joe, keep baiting. I am going to ignore you from now on. I just thought perhaps we had a different point of view, but you have now proven you are trying to troll me.  :-DD
:-DD

Lightages, no more Mastechs as well.  I'm not sure how many we have checked now with the re-branding BS but like the UNI-Ts they never seem to hold up very well.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on October 21, 2015, 01:05:02 pm
Yeah, I have yet to see a Mastech that I would buy at any price,let alone recommend even they would pass any kind of test. They all seem to be very poorly made. The Uni-Ts were just ideas to show the difference, if any between the old and new high end models.

I am still up for donating towards the testing of other meters.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on October 21, 2015, 03:29:19 pm
Great job Joe. :clap:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dexters_lab on October 21, 2015, 05:30:18 pm
If you haven't seen it yet, DextersLab2013 posted a video using his new generator.    Looks like it does a nice job on them. 

 :-+ >:D

thats just shy of 1700v, 185uF

it's a bit of a sledgehammer in comparison to your generator Joe, but it's good to show how well the blast protection might work  :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on October 21, 2015, 08:28:16 pm
That 107 is very hardened and I would have no problems at all about giving one to someone as a basic meter.   
I also like the fact that there's no 250mA fuse that costs $12+shipping to replace.
It is useful.

Sure, but very delicate.

And in Fluke's case, very expensive.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on October 21, 2015, 09:56:59 pm
Of concern to this thread is the sample size of n =1 for each meter and any generalizations to the rest of the production runs of each meter.

If a manufacturer does tight quality control, and Fluke makes public it follows a form of six sigma manufacturing, then the probability of product defect hover about 3 ppb. 

Thus, a single test device can be representative of the entire population, as any product in this batch is expected to be effectively defect free and made to perform as designed.  You could say the chance the single device doesn't represent the population its from is ~ 3 ppb.

Note, this holds only for a manufacturer that has a strict QC method like six sigma.  So for the other meters where the quality control is unknown, one cannot not say they failed or survived due to sample bias, or chance, a 'fluke'  :palm: ;).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 21, 2015, 10:58:13 pm
Saturation,

I believe what you wrote to be true as well and had posted on this subject a few pages back in an attempt to address mtdoc's comments.  See below.   Thanks for posting.   


Interesting and entertaining videos.  Well done.

That said however, I would hardly call a one-off test of this sort any definitive test of a meter's robustness. 

Sure, if the Fluke 87 had failed spectacularly at a relatively low voltage that might say something, but that's not what happened.

If 100 fluke 87s had been compared to 100 101s across a variety of controlled tests then you might be able to make a valid conclusion about their relative "robustness".

I do think the Fluke 87V is a bit overpriced at $400 compared to its competitors but that's a different issue.

In the end, any test with an n=1 is just anecdotal in nature and not evidence. But it does make for fun viewing an interesting discussion.

Any test engineer or working scientist knows that you can't draw any meaningful conclusion from testing with an n=1 (or 2) - so all this teeth gnashing about exactly what these tests ultimately prove is misplaced IMHO.  They are certainly interesting and entertaining and make for a good discussion. I say well done Joe! (even though I know he has not tolerated my critique in the past).  Joe's biases come through but that is not a criticism - we all have our biases.  Any strongly held opinions about the  87V based on these tests are unfounded IMO but that's ok - we all have opinions..


In the first series of meters I mentioned that I had only tested one of each meter and that this was not much of a sample size.  Obviously, we are never going to be looking at large same sizes for any of these reviews.    Many benchmarks are performed with minimal sample sizes and in some cases, even one sample  but it does not mean they are completely invalid or that we can not learn anything from them.   Statisticians are rolling there eyes now..... 

Let me start by saying that these products were obtained through normal channels.  In most cases they were procured through Amazon.   Why does this matter?  Well, if say the manufacture sent me meters directly for these tests, how would we know that these products were not special in some way in order to bias the tests?  So to be clear, in no case did Fluke or Brymen supply me with product for these reviews.   This is what I don't like about regulatory groups.  The companies ship the products to be evaluated.  Many times these may not be the final production parts.   They may need to make some changes and go back and forth a few times before they are certified.    In the end, do we really know the product that was certified is what will be supplied to you and me?  Or, will a MOV be removed to increase profits by some accountant.   Maybe a part was changed out for a cheaper part of what they think is the same quality and the product was not re-certified because of cost, time, etc.     So, because I obtain the meters my some means that the average person could,  I am making some assumption that the meters I test represent the average meter.     

Now this makes for another assumption.  I assume that the manufacturer has their process under control.    They may not and then my first assumption that my one meter represent the mean goes out the window.      So we could say for example, the 87V I tested does not represent the average 87V.  It was some outlier.  Then we also say that Fluke does not have control of their process.    Now I doubt they have a process control problem, but I don't know.  I would more guess that the meter just does not handle the transient by design in these other modes besides voltage.   It's a pretty old design when compared with the 101.  I am sure they have learned a few things and have improved their designs.   I have no data to back that up and am just giving them the benefit of the doubt. 

In the case of the 101 being the only meter to survive my first round of testing, we had a member repeat these tests using a different meter and commercially available transient generator.    The results were the same.   Even at 12KV they could not damage the 101.   I went further and increased the FWHH and added 1KV and still could not damage it.    I have some level of confidence that the 101 is very robust.   That said, I was not too surprised that the 107 survived this same test.     

Now had say the Fluke 87V failed at 2KV and the Brymen BM869s at 2.5KV, I would say we are well withing the margin of error of my tests and the meters them selves (what brand of components, date codes, etc).  But this is not at all what happened.   We have one meter living at 6KV and one failing at 1.5KV.    That's a pretty big window.   I bet if I tested 100 pcs of each meter we could find some 87Vs that would live to 1.7KV and some Brymens that fail at 5.5KV.      If the windows were much wider, I would really question their process and quality control. 

The problem in gaining confidence in the tests is that we are no longer talking about low cost meters.   I doubt that our members are going to run out and buy an 87V and BM869s knowing the 87V may be damaged at 1.5KV just to repeat the test and see which is more robust.     

I don't believe I have skewed the results or biased the test towards one brand or another.     Again, take it for what it is worth or feel free to step up to the plate and take a swing.   I am open to what ever tests the group can come up with to help determine which meters are more electrically robust than others.   



Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 21, 2015, 11:08:39 pm
If you haven't seen it yet, DextersLab2013 posted a video using his new generator.    Looks like it does a nice job on them. 

 :-+ >:D

thats just shy of 1700v, 185uF

it's a bit of a sledgehammer in comparison to your generator Joe, but it's good to show how well the blast protection might work  :-DD

If we call what you have a sledgehammer, I would say mine is a tack hammer.    And what PhotonicInduction has is a pile driver.  :-DD   

I bet the Fluke 101 and 107 would survive on your generator all day long.   Much of the time I monitor the voltage to see what to meter is doing and many of them don't draw much until they get ready to fail.   I would NOT hook your 87V to it!!   That 1.7KV may be enough to push it over the edge.    :-DD 

I look forward to seeing more videos of it doing some meter damage and getting that thing to put out is maximum blast.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dexters_lab on October 22, 2015, 08:23:34 am
If we call what you have a sledgehammer, I would say mine is a tack hammer.    And what PhotonicInduction has is a pile driver.  :-DD   

I bet the Fluke 101 and 107 would survive on your generator all day long.   Much of the time I monitor the voltage to see what to meter is doing and many of them don't draw much until they get ready to fail.   I would NOT hook your 87V to it!!   That 1.7KV may be enough to push it over the edge.    :-DD 

I look forward to seeing more videos of it doing some meter damage and getting that thing to put out is maximum blast.

have both the 101 and 107 plus a couple of other older Mastech jobs

happy to put anything on it, well apart from my own  ;D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 22, 2015, 11:57:39 am
You know you want to try that 101 on it!!   :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 30, 2015, 02:46:28 pm
I would like to get somewhere in the maybe a quarter cycle of a home feed.   Say, 220v 200A 60Hz or just to see the effects on these dead meters before I recycle them.     

:-+ >:D

thats just shy of 1700v, 185uF

it's a bit of a sledgehammer in comparison to your generator Joe, but it's good to show how well the blast protection might work  :-DD

Let's assume that is 267J at the connector with no sort of network and you can double that at the connector.   I think this is roughly what I would like to see.

If I target say 1/4 cycle of a 440 line at 200A, that's 366J.   

Because some of the meters do not arc until much higher voltage than what you have,  my plan is to have a second low voltage high energy generator that is triggered from the high voltage transient of the first generator.     Staying with a stored system and keeping the voltages low should keep it very small and somewhat safe.   

I know it is still no where near the energy of what you could see in real life but it may provide some insight as to how these meters would handle a higher energy transient.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 30, 2015, 11:52:44 pm
It's a start...

https://www.youtube.com/watch?v=9ii55eHfUWY (https://www.youtube.com/watch?v=9ii55eHfUWY)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on October 31, 2015, 01:56:23 am
Damn that looks promising. I love how when you hit that CEM, you can actually see lights cascading behind the board. A lot longer lived than I expected.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 31, 2015, 02:34:08 am
Damn that looks promising. I love how when you hit that CEM, you can actually see lights cascading behind the board. A lot longer lived than I expected.

I felt it was good enough to move forward with it.   It's too bad that all the other modes failed.  Really it was a pretty tough meter compared with most of them.   

All of the parts arrived from Digikey today.  Here it is for it's first tryout with the throttle all the way open. 

https://www.youtube.com/watch?v=mPXizuSZACs&feature=youtu.be (https://www.youtube.com/watch?v=mPXizuSZACs&feature=youtu.be)

This things still just a toy.   Imagine what a real arc flash is like.   If a meter comes apart with this little thing, I would guess you have some problems.   

I need to get it into a box and make up some sort of safety glass cover for the meter holder.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: crispy_tofu on October 31, 2015, 02:38:09 am
Wow, packs quite a punch  :box:  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 31, 2015, 05:08:35 pm
If it can explode a light bulb what will it do to 5KY's Circuit-Test DMR-6550?   Watch and find out. 

https://www.youtube.com/watch?v=yE2tl8NHIgM&feature=youtu.be (https://www.youtube.com/watch?v=yE2tl8NHIgM&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on October 31, 2015, 07:54:50 pm
Is it bad that I am actually laughing at this? The power is a HUGE step up.  :box:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on October 31, 2015, 08:35:18 pm
Is it bad that I am actually laughing at this? The power is a HUGE step up.  :box:

Can't blame you for laughing.   It is pretty entertaining to see up close.   

I'm not sure what if anything we can learn from it as the energy is way too low to simulate a real world condition.    Still, it's not something I would recommend the novice try as a starter project.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 01, 2015, 11:06:15 pm
I spent some time on the case for the new generator.   1/4" thick plate aluminum with a phenolic back plate.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 02, 2015, 01:49:34 am
Sanded out the machine marks and started working on the cover for the case.  Hope to have it finished by the end of the week.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on November 02, 2015, 03:28:43 am
Beautiful start to the case! Those binding posts though, hot damn.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Vgkid on November 02, 2015, 03:39:05 am
Those are some beefy lugs.
Where did you get those rack handles.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 02, 2015, 03:06:52 pm
Beautiful start to the case! Those binding posts though, hot damn.

Thanks.   Glue set, some sanding, stain and first coat of poly is on. 

Those are some beefy lugs.
Where did you get those rack handles.

I don't remember what those handles came off of but would guess it was some old gear I scrapped.   

When I started this project, I was thinking BIG cables with very low inductance.   So far I have only been using some test lead wire and may just go with that.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 04, 2015, 03:02:47 am
Finished up the new transient generator today and tried it out on some of 5kys meters.   I had a different knob picked out for it, but seem to have lost it.  So the small black one is there until I find it. 

https://www.youtube.com/watch?v=3fYVaXz8lVk&feature=youtu.be (https://www.youtube.com/watch?v=3fYVaXz8lVk&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 04, 2015, 07:19:58 pm
Well, she died today.  Wasn't even a fire ball of death.  Actually it wasn't even turned on.   The margins were just too tight on the diodes.   Was running about 80% and suspect the stray inductance caused enough back emf to wipe them out.   Ordered some new parts and will add protection for them.   Shouldn't take much to solve it.   On the up side, the diodes seem to handle the forward currents just fine.   Also the protection for the capacitor bank seems to have worked.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: dexters_lab on November 04, 2015, 10:13:32 pm
I would like to get somewhere in the maybe a quarter cycle of a home feed.   Say, 220v 200A 60Hz or just to see the effects on these dead meters before I recycle them.     

:-+ >:D

thats just shy of 1700v, 185uF

it's a bit of a sledgehammer in comparison to your generator Joe, but it's good to show how well the blast protection might work  :-DD

Let's assume that is 267J at the connector with no sort of network and you can double that at the connector.   I think this is roughly what I would like to see.

If I target say 1/4 cycle of a 440 line at 200A, that's 366J.   

Because some of the meters do not arc until much higher voltage than what you have,  my plan is to have a second low voltage high energy generator that is triggered from the high voltage transient of the first generator.     Staying with a stored system and keeping the voltages low should keep it very small and somewhat safe.   

I know it is still no where near the energy of what you could see in real life but it may provide some insight as to how these meters would handle a higher energy transient.   

just catching up on your new build Joe, you  really do finish off projects! Your new generators look beautiful, nice work... can we see inside the new higher energy unit, what volts/capacitance do you have in there? :-+

i still have not figured out the point where the magstim fires, a load of 100k ohm and it wont, but 1k does, i can put a coil in parallel with the DUT but then i am wasting energy in the coil. Your approach to use low energy high voltage to trigger the main charge is interesting... much like a xenon flash tube circuit in a way

i am taking the magstim over to a friend tomorrow, see if we can figure out why i am only getting 1700v instead of 2800v on the cap... i am sure we'll get around to making some things expire too, maybe i should try the fluke 101? >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 05, 2015, 12:21:32 pm
Thanks.   
just catching up on your new build Joe, you  really do finish off projects! Your new generators look beautiful, nice work... can we see inside the new higher energy unit, what volts/capacitance do you have in there? :-+

i still have not figured out the point where the magstim fires, a load of 100k ohm and it wont, but 1k does, i can put a coil in parallel with the DUT but then i am wasting energy in the coil. Your approach to use low energy high voltage to trigger the main charge is interesting... much like a xenon flash tube circuit in a way

i am taking the magstim over to a friend tomorrow, see if we can figure out why i am only getting 1700v instead of 2800v on the cap... i am sure we'll get around to making some things expire too, maybe i should try the fluke 101? >:D
,
Thanks.   Yes, I really "finished this project off" yesterday.    :-DD

There's not much in them both.    The new unit has a power supply, capacitor bank with some protection for it, an output network and a trigger circuit.    I originally thought about making the bank using different voltage/capacitance values  and then having a waveform with multiple breakpoints.   But I already had the generator that could produce several KV, so it was easier to just use the lower voltage caps and design a way to trigger it.   The problem I see is that some of the meters I have tested did not break down even with 6KVish.   If they don't break down, the second generator is not going to cause any damage.

Are you sure that your generator does not fire?  Are you putting a scope across the outputs and looking at them or still using the loop?         

With your generator being designed for one specific purpose, they may not have a network like a typical combo generator would have.   For a combo, they spec an open and short condition for voltage and current.   In the generators I have made, I am keep the open circuit voltage  tamed to something like the IEC waveform.  But for a short, I don't have the energy available (for good reason).   And again, even with the new generator, while I can output a 200V+ volt AC wave while I am injecting the transient, the two are not in sync and the transient is coupled to ground not riding on top of the AC.   And, I limit the AC to typically < 50mA but can only go as high as 500mA (for good reason).    All that to say, in open circuit mode, the majority of the energy is dissipated in the output network.    With a short (or a meter breaking down) some of the energy is dissipated in the output network.   

The following paper may be of interest to you.
http://www.denverpels.org/Downloads/Denver_PELS_20070918_Hesterman_Voltage_Surge_Immunity.pdf (http://www.denverpels.org/Downloads/Denver_PELS_20070918_Hesterman_Voltage_Surge_Immunity.pdf)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 07, 2015, 05:54:24 am
Increase the margins and added a couple of layers of protection for the diodes.  Ran several tests with it and it seems very robust now.   

Video showing 5ky's UTL meter along with some of the fuses that were used in these meters.    Why a company would put glass in a modern meter, I'm not sure.     

https://www.youtube.com/watch?v=cWKoRxNEsXk&feature=youtu.be (https://www.youtube.com/watch?v=cWKoRxNEsXk&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 09, 2015, 03:45:26 am
5ky's Fluke 107 is ran with the new setup.    Keep in mind it had been damaged during my previous tests.   

https://www.youtube.com/watch?v=h27MP58P4pg (https://www.youtube.com/watch?v=h27MP58P4pg)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 15, 2015, 04:56:20 pm
Cen-Tech 90899 meter with test leads on the new generator. 

https://www.youtube.com/watch?v=GHWb0kjrIY0 (https://www.youtube.com/watch?v=GHWb0kjrIY0)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on November 15, 2015, 06:23:57 pm
Nice test with the centech. Unacceptable to have the test less blow out like that

Sent from my LG-ls990 using Tapatalk

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 16, 2015, 12:14:18 am
Agree!  I would not want a live probe flailing around in front of me.     I tossed out most of the probes that came with the meters I first tested.  I think 5ky did the same.  It may have been interesting to pulse test these as well. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 18, 2015, 04:13:29 am
I made a viewing window using 1/2" Lexan.   Also shown is a new connector I made that ties the two generators to the meter.   I can use the standard banana cable shown, or I can also plug the meters test leads into this as well without using the test lead to banana adapters.       
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 20, 2015, 04:31:04 am
Looks like  I can get it through Amazon.   They also offer the 17B with a few more features.

http://www.amazon.com/SSEYL-Fluke-Digital-Multimeter-F15B/dp/B00SEZU4KO/ref=sr_1_4?ie=UTF8&qid=1447992356&sr=8-4&keywords=fluke+15b%2B (http://www.amazon.com/SSEYL-Fluke-Digital-Multimeter-F15B/dp/B00SEZU4KO/ref=sr_1_4?ie=UTF8&qid=1447992356&sr=8-4&keywords=fluke+15b%2B)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on November 20, 2015, 06:25:12 am
Finally got around to looking at this link showing the 15B+.   That's a step up over the 101 and 107.    I wonder if it is as robust. Any idea what it would take to get it sent to the US?

http://www.aliexpress.com/store/product/Fluke-15B-F15B-Digital-Multimeter-Auto-Manual-Range-AC-DC-1000V-10A-40M-ohm-Capacitance-100uF/917544_1187715988.html (http://www.aliexpress.com/store/product/Fluke-15B-F15B-Digital-Multimeter-Auto-Manual-Range-AC-DC-1000V-10A-40M-ohm-Capacitance-100uF/917544_1187715988.html)
Just money Joe.
As I've said I'll put up USD50.

Looks like  I can get it through Amazon.   They also offer the 17B with a few more features.

http://www.amazon.com/SSEYL-Fluke-Digital-Multimeter-F15B/dp/B00SEZU4KO/ref=sr_1_4?ie=UTF8&qid=1447992356&sr=8-4&keywords=fluke+15b%2B (http://www.amazon.com/SSEYL-Fluke-Digital-Multimeter-F15B/dp/B00SEZU4KO/ref=sr_1_4?ie=UTF8&qid=1447992356&sr=8-4&keywords=fluke+15b%2B)

The only difference betwen the 15 and 17 is the front case and keypad membrane with the extra buttons.
AFAIK they have the same PCB.

Note, the newer + versions have a backilght now.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on November 21, 2015, 07:40:23 pm

Would it be better to run the 115 or the 15B+?    It seems like the 115 would be more common but the 15B+ may be a newer design.
I'm not aware if the 15B is available directly from Fluke internationally. AFAIK the 15B is a China market unit only, those that I have got have no warranty outside China.
Despite this I've found them a quite good DMM for basic bench work and I have some confidence in their safety ratings as the Chinese also have 230VAC mains like here in NZ.

The 115 on the other hand is an international product, probably more widely used  :-// but it's hard to beat the 15B or the never plus model for price.

As we know any unit that you get and expose to your lady devil  >:D wil not be much good for further use so I'll put up USD50 if somebody adds the extra USD25 to get a 15B for you to test in the name of science.  ;)

Tell us what you'd like Joe.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on November 21, 2015, 09:16:31 pm
Finally got around to looking at this link showing the 15B+.   That's a step up over the 101 and 107.    I wonder if it is as robust.  Any idea what it would take to get it sent to the US?
It's an Asian model, so... you have to buy on eBay/aliexpress/whatever.

On the plus side: That means shipping is included!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 21, 2015, 09:50:12 pm
It looks like I can get the 15B+ through Amazon but if people would rather see the 115 or 117 ran, I have no problem getting one of them.    I haven't looked into Paypal yet.  So don't worry about it.   

As we know any unit that you get and expose to your lady devil  >:D wil not be much good for further use so I'll put up USD50 if somebody adds the extra USD25 to get a 15B for you to test in the name of science.  ;)

Tell us what you'd like Joe.

 :-DD   Not all of them die.    The 101 is still in great condition as far as I know.  I have never had it apart.   Even 5KY's 107, AM530 and my AM510 are all in good working condition.   The UT90 still works after damaging the traces twice (may need to do something about this).   Then there is the BM869s which is really proving to be a good little meter.   


After putting together the spreadsheet and reviewing the videos, one thing that is interesting is that both the Fluke 87V and the UNI-T 139C had the most thumbs down.   I assume both are popular meters is partly why.   Also that I did not increment the energy to see at what level these failed at compared with the other meters.   Hard to say. 

I had reran an 87V to find where it actually fails as a few people had asked about it.   No one has ever asked about the 139C but   now that I have a way to repeat the tests it may be interesting to see where it falls in.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 26, 2015, 05:03:00 pm
It's a little late to roast them for Thanksgiving but the the 17B+ is on it's way along with a few other meters.  I like the features the 17 has and the cost was a wash.

 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: vinicius.jlantunes on November 26, 2015, 05:16:16 pm
It's a little late to roast them for Thanksgiving but the the 17B+ is on it's way along with a few other meters.  I like the features the 17 has and the cost was a wash.

 :-+
I own a 17B+ and am curious to see how it goes.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 26, 2015, 05:47:43 pm
It's a little late to roast them for Thanksgiving but the the 17B+ is on it's way along with a few other meters.  I like the features the 17 has and the cost was a wash.

 :-+
I own a 17B+ and am curious to see how it goes.

Do you like it?   Looks like a nice little meter. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: vinicius.jlantunes on November 28, 2015, 01:10:52 am
It's a little late to roast them for Thanksgiving but the the 17B+ is on it's way along with a few other meters.  I like the features the 17 has and the cost was a wash.

 :-+
I own a 17B+ and am curious to see how it goes.

Do you like it?   Looks like a nice little meter.

Yeap! Pretty solid, The only thing I think could be better is the continuity test. But still a very good meter.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on November 28, 2015, 01:27:20 am
It's a little late to roast them for Thanksgiving but the the 17B+ is on it's way along with a few other meters.  I like the features the 17 has and the cost was a wash.

 :-+
I own a 17B+ and am curious to see how it goes.

Do you like it?   Looks like a nice little meter.

Yeap! Pretty solid, The only thing I think could be better is the continuity test. But still a very good meter.
That's a broad statement, don't you just mean it could be faster?

In this thread the 15/17B stack up pretty well against others in terms of voltage and current specs for continuity test:
https://www.eevblog.com/forum/testgear/multimeter-with-low-continuity-test-voltage/ (https://www.eevblog.com/forum/testgear/multimeter-with-low-continuity-test-voltage/)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 28, 2015, 06:41:46 am
There's fast, then there is Van Halen Eruption fast!  :-DD     

I did play with the continuity test on the 17B+ and it is a bit on the slow side.   I'll get some real numbers off it.   I plan to update the spreadsheet as I go now and may add the continuity testing I have done as well.   

Quote
"Pretty solid"
  :-DD  This thing feels very solid compared with most of the meters I have looked at.    It's not at all what I was expecting.   

Side tracked a bit today trying to catch on things.   Took about an hour to take my Laptop apart, fix a connector and put it back together.   My old HP6285A died about a month ago.  This is the third time I have been into it.   This time was a real bugger.   These have a dual SCR pre-regulator.  This section was not working.  I thought I may have damaged something in the over voltage fault circuit but everything checked out.   After about an hour, finally found that the trigger transformer had a bad solder joint on the primary side.  I am watching it bake for a while before calling it quits for the day.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: vinicius.jlantunes on November 28, 2015, 12:12:59 pm
That's a broad statement, don't you just mean it could be faster?

Yes that's what I mean, that it could be a bit faster. The rest is fine indeed. But it's nitpicking really, I think it's a great meter, I'm even thinking about getting one more for the lab!
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 28, 2015, 04:53:34 pm
After letting the meter sit at room temp after shipping (winter is setting in), I checked it for calibration.   For the most part, seems alright but the DC voltage is out more than I would have expected.   

At 10V 17B+ reads 9.95, or -50mV error
At 1V, 17B+ reads 0.994, or -6mV error

The specs state +/-0.5% of reading + 3 counts. On the 40V scale, the res is 10mV.   So if I am reading it right, a 10V signal could be off by +80/-20mV.     On the 4V scale, it's 1mV res, or +8/-2mV.   

Maybe I am not reading the spec right, or my math is wrong.  Seems like this meter is out on DC volts.  The rest of it looks good.  Maybe one of their DC calibration standards is off where the meters are being aligned.  :-//

My reference was last checked for cal last summer.   

Someone had posted that the 17B and 17B+ were the same board.  This is not the case at all.   The 17B+ is aligned digitally, not with pots. 

I would expect most of the higher end meters are aligned this way today.   I wonder with these meters, does Fluke make the tools available to align them?

At a glance, the layout looks alright.  All the basic parts in place you would expect.   They used a lot of grease on this one.  It was coming out of the vias and the center shaft of the rotary switch has so much it covers the back case half.   

Here are a few pictures of the 17B+ PCB and what I am calling excessive grease, along with a picture of my Fluke reference standard and HP34401 (both in cal)...
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on November 28, 2015, 06:14:01 pm
When it specified +3 counts, it is a bit confusing. It really means ±3 counts. Why they don't say it that way I don't know. So it really is ±80mv allowable error on the 40V scale when reading the 10V source.(edited for clarity)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Wytnucls on November 28, 2015, 06:19:49 pm
Fluke 17B+ manual:

Accuracy Specifications
Accuracy is specified for 1 year after calibration, at operating temperatures of 18 °C to 28 °C, relative humidity at 0 % to
75 %. Accuracy specifications take the form of: ±([% of Reading] + [Number of Least Significant Digits]).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: DG5SAY on November 28, 2015, 07:01:58 pm
Hi,
I have a 15B+ also with too much error.

At 10VDC, my 15B+ reads 9.87, or -130mV error
At 40VDC, my 15B+ reads 39.52, or -480mV error, thats nearly a half a Volt!! :--

The specs state for the 15B+ is also +/-0.5% of reading + 3 counts, like the 17B+.   

And yes, the 15B+ is also aligned digitally, not with pots, the older 15B has a pot to align.

Has anyone a tool to make a digital alignment?

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on November 28, 2015, 07:17:07 pm
Someone had posted that the 17B and 17B+ were the same board.  This is not the case at all.   The 17B+ is aligned digitally, not with pots. 
Not I, but I did state the 15B and 17B have the same board, maybe you got you wires crossed Joe.  :-DD

This has been mentioned in threads in the past, the only differences being a different front panel and 2 additional buttons on the rubber membrane for the extra functins of the 17B.

It wouldn't surprise me at all if the 15 and 17 B plus models shared the same PCB too.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 28, 2015, 07:55:21 pm
Someone had posted that the 17B and 17B+ were the same board.  This is not the case at all.   The 17B+ is aligned digitally, not with pots. 
Not I, but I did state the 15B and 17B have the same board, maybe you got you wires crossed Joe.  :-DD

This has been mentioned in threads in the past, the only differences being a different front panel and 2 additional buttons on the rubber membrane for the extra functins of the 17B.

It wouldn't surprise me at all if the 15 and 17 B plus models shared the same PCB too.

 :-DD So, I hunt down what  I had searched for and behold, it was your post  :-DD

Taken from the following:
https://www.eevblog.com/forum/testgear/fluke-17b-%28plus%29/ (https://www.eevblog.com/forum/testgear/fluke-17b-%28plus%29/)

Thank you all for the replies so far. Does anyone know if the continuity test on the new 17B+ latches on good or is still scractchy like what Dave tested on the review of the old 17B??
AFAIK the internals are the same as a 15B and the continuity test is excellent for a cheap DMM

The way I read this, your claim is the 17B+ has the same internals as the 15B.    No problem if I misunderstood.  Just wanted to make it clear that it is a new design.

When it specified +3 counts, it is a bit confusing. It really means ±3 counts. Why they don't say it that way I don't know. So it really is ±80mv allowable error on the 40V scale.

I guess the ink for the  "/-" added too much cost to the manual.  I saw it was +3 counts on their website as well.  So, let's then assume this meter is within their spec.   Still surprised it is off by this much.   I was thinking it would be right down the center.    Fairly deadly on all other modes.   

Hi,

Has anyone a tool to make a digital alignment?

I thought about getting the 15B+ to test.   It was a little less expensive.    If the boards really are the same, I would assume the 15B+ will fail around the same level as the 17B+.   

Seems like Fluke would make this tool available to the cal houses.   I was going to look into if Brymen offers the tools as well.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on November 28, 2015, 11:13:16 pm
At 10VDC, my 15B+ reads 9.87, or -130mV error
At 40VDC, my 15B+ reads 39.52, or -480mV error, thats nearly a half a Volt!! :--
1) What are the specifications for your 10V and 40V reference? 
2) Are you using a variable power supply set at 10V and 40V for comparison to the Fluke?
3) If you hook another meter to the same 10V and 40V reference source, what readings do you get?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 29, 2015, 07:27:26 am
If lightages is correct and the spec is wrong (which makes more sense), at 40 volts you could have as much as +/- 230mV. 

Using my bench meter as a reference, I set the supply to 40 volts and measure it with the 17B+ and got 39.83 or about 170mV of error not including the HP's contribution.   It seems alright but still surprised it is this far out.   Sorry about the dog hair.....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: DG5SAY on November 30, 2015, 07:51:50 am
At 10VDC, my 15B+ reads 9.87, or -130mV error
At 40VDC, my 15B+ reads 39.52, or -480mV error, thats nearly a half a Volt!! :--
1) What are the specifications for your 10V and 40V reference? 
2) Are you using a variable power supply set at 10V and 40V for comparison to the Fluke?
3) If you hook another meter to the same 10V and 40V reference source, what readings do you get?

1): 0.005% at VDC, good enough for a 15B+
2): no, the voltage is comming direct out of a Fluke 5100A
3): see pictures
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on November 30, 2015, 08:05:30 am
And yes, the 15B+ is also aligned digitally, not with pots, the older 15B has a pot to align.

Has anyone a tool to make a digital alignment?

It wouldn't surprise me if Fluke deliberately doesn't calibrate them perfectly. It would really eat into 87V sales if they did.  :popcorn:

PS: I was just searching the web and can't find anybody reverse engineering the calibration.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on November 30, 2015, 02:39:53 pm
1): 0.005% at VDC, good enough for a 15B+
2): no, the voltage is comming direct out of a Fluke 5100A
3): see pictures

Wow!   I am curious how tight it is in the other modes.   By far, the DC volts was off the furthest with the 17B+ I have. 

And yes, the 15B+ is also aligned digitally, not with pots, the older 15B has a pot to align.

Has anyone a tool to make a digital alignment?

It wouldn't surprise me if Fluke deliberately doesn't calibrate them perfectly. It would really eat into 87V sales if they did.  :popcorn:

PS: I was just searching the web and can't find anybody reverse engineering the calibration.

I doubt it would hurt the sales of the 87V too much.   The 87V has a bar graph and RMS which the 17B+ does not.   Even so, people are going to buy what they want.  The 87V is popular.  You want to be part of the crowd don't you?   

Testing for the 17B+ has started.   Because I have only the one meter to test, I hope to do a better job with the video.  Taking a little more time with it and making it more of a review.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on November 30, 2015, 10:54:27 pm
3): see pictures
Wow, the 15B+ is way out of spec (0.5% + 3 digits) at 9.84 and 39.40.  Definitely  :--

4) Was the 15B+ out of spec since day 1, brand new, or has this meter drifted over time?

off topic: I like the bigger digits compared to the 87V.

PS. I had to ask regarding your references because I had no idea what you had.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 01, 2015, 06:39:14 am
Well, it's been a long two day blitz of nothing but 17B+ testing.  The video is being uploaded now.   I made it more of a review and compared it with what I think would be a similar product from a different brand.   All in all, it's not a bad meter. 

I found a mistake in the spreadsheet as well that I have corrected when I added the results for the 17B+.   I have also added a second page for the continuity tests I have done.     

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 01, 2015, 07:11:03 am
Before I forget, I thought I saw a very strange condition when using the 17B+.   It was after one of the tests and I was verifying that the meter was functional.   What I though I had happen was I had it get into a state where the the RED warning light came on and stuck with a very small signal applied.   I tried to reproduce it with no luck.   Maybe not enough coffee or not enough sleep.   :-// 

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: DG5SAY on December 01, 2015, 07:52:37 am
3): see pictures
Wow, the 15B+ is way out of spec (0.5% + 3 digits) at 9.84 and 39.40.  Definitely  :--

4) Was the 15B+ out of spec since day 1, brand new, or has this meter drifted over time?

off topic: I like the bigger digits compared to the 87V.

PS. I had to ask regarding your references because I had no idea what you had.

4): it was out of spec "since day 1"! I own it now for 6 months and it has not changed since then.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 01, 2015, 01:10:57 pm
Here is my 17B+ review/test.   It's long....

https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be (https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be)

DG5SAY, are all of the other functions in-cal?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on December 01, 2015, 02:34:19 pm
Here is my 17B+ review/test.   It's long....

https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be (https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be)

DG5SAY, are all of the other functions in-cal?

Starts the video saying, I'm not going to do a full review....

Does a full review :-DD

That being said, nice review so far. Still watching/listening to it as I work on a document for work.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: DG5SAY on December 01, 2015, 03:55:59 pm
Here is my 17B+ review/test.   It's long....

https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be (https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be)

DG5SAY, are all of the other functions in-cal?

ACV is also out of spec (see my attachment in reply # 618), the other functions I have not yet thoroughly checked
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: retiredcaps on December 01, 2015, 04:25:21 pm
4): it was out of spec "since day 1"! I own it now for 6 months and it has not changed since then.
I'm surprised you didn't ask for a replacement or refund from seller if it was out of calibration since day 1?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: DG5SAY on December 01, 2015, 07:40:34 pm
4): it was out of spec "since day 1"! I own it now for 6 months and it has not changed since then.
I'm surprised you didn't ask for a replacement or refund from seller if it was out of calibration since day 1?

Sure, I did. But first, they don´t believe me. When I sent them my measurements, they offered me to exchange the multimeter. I should have sent it, however, at my own costs to China, clearly that I neither the device nor the money would have seen again! So I made a negative review and will never buy anything again from this eBay-Shop. End of the story.  :--

It is a multimeter produced exclusive for the chinese market. F... these chinese multimeter. I will buy from a german dealer with german guarantee only. From an offical german Fluke dealer this cheap 15/17B+ models are not available.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: vinicius.jlantunes on December 01, 2015, 11:08:09 pm
Well not only China I can assure you. Other non prime markets such as Brazil as well. That's how I got mine from the authorized distributor, and it came with a cal certificate. And most surprisingly, it is made in USA as far as I can tell!
So long story short, yours could be bad but it doesn't make all of them bad. It's still a fluke and miles ahead at least of all other crap available around here.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 02, 2015, 05:18:56 am
Here is my 17B+ review/test.   It's long....

https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be (https://www.youtube.com/watch?v=DvC5woDYGd4&feature=youtu.be)

DG5SAY, are all of the other functions in-cal?

Starts the video saying, I'm not going to do a full review....

Does a full review :-DD

That being said, nice review so far. Still watching/listening to it as I work on a document for work.

Thanks.   Dave and 5Ky's meter reviews go into other areas that I choose not to.  If there is something you would like to see that I did not cover, let me know.     

Had the the 17B+ had a crest feature or a bar graph, I would have shown them off as well.  I did not show the manual but there was not an English version included.  I also did not give a conclusion in the end.   I thought about just putting the original generator back to when it was used to test the Fluke 101 but if the 17B+ failed, we would not know how close it was.   So give me some time to sort out my next move and then I will do a part 2.     

In the mean time, look what showed up.   I know I swore I would not waste my time on another UNI-T.  When I was updating the spreadsheet and I saw number of thumbs down was about the same as the thumbs up for this video.   I see the thumbs down as a good thing as it means it's a popular meter.  Sadly, there was no good feedback.  However,  it was the only other meter besides the 87V where I was not sure at what level it failed.   Just for completeness, I decided to rerun the test using the new setup.   

The last two that 5KY sent were the UT61D and E.  These meters could not even survive the piezo  grill ignitor test.   You should see some of the ESD we get when winter comes and the house is dry...  So I am not sure yet what I am going to do with this one.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 02, 2015, 06:04:35 am
Sure, I did. But first, they don´t believe me. When I sent them my measurements, they offered me to exchange the multimeter. I should have sent it, however, at my own costs to China, clearly that I neither the device nor the money would have seen again! So I made a negative review and will never buy anything again from this eBay-Shop. End of the story.  :--

Sounds like you and the seller both had bad luck. What would you have done if you were the seller trying to sell multimeters with only one or two dollars profit margin?

PS: What happens if you turn the little trimmer next to the calibration connector? Does anybody know?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: DG5SAY on December 02, 2015, 07:42:40 am
Sure, I did. But first, they don´t believe me. When I sent them my measurements, they offered me to exchange the multimeter. I should have sent it, however, at my own costs to China, clearly that I neither the device nor the money would have seen again! So I made a negative review and will never buy anything again from this eBay-Shop. End of the story.  :--

Sounds like you and the seller both had bad luck. What would you have done if you were the seller trying to sell multimeters with only one or two dollars profit margin?

PS: What happens if you turn the little trimmer next to the calibration connector? Does anybody know?

And yes you´re right, that´s why I don´t struggle with them. It is not worth my time.

There is NO trimmer total in a 15B+! Only the 17B+ has a trimmer, I think it´s for temperature calibration.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 04, 2015, 04:14:09 am
Well, the 17B+ failed tonight.   I was pushing it pretty hard.   It looks like I may be able to repair it but will need to order parts.   I am impressed with how robust all three of the low end Fluke meters I have looked at.     
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 05, 2015, 07:02:06 am
I just finished the video showing the conclusion of my 17B+.   I'll upload the new spreadsheet later on in the day. 

https://www.youtube.com/watch?v=wiiii0gdcbM&feature=youtu.be (https://www.youtube.com/watch?v=wiiii0gdcbM&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 06, 2015, 04:42:00 pm
Ah.... The smell of good coffee and burnt UNI-T parts in the morning...   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on December 06, 2015, 07:10:56 pm
Ah.... The smell of good coffee and burnt UNI-T parts in the morning...
:-DD
Oh dear, at least they're consistant.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 07, 2015, 03:35:51 am
Return of the UT139C.

https://www.youtube.com/watch?v=zFvuigSS2Xk (https://www.youtube.com/watch?v=zFvuigSS2Xk)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 09, 2015, 01:41:34 am
Second half of my 139C testing.
https://www.youtube.com/watch?v=F-VaE1Gn1Nw (https://www.youtube.com/watch?v=F-VaE1Gn1Nw)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 11, 2015, 03:03:35 am
When I got the Brymen BM869s, I made a few videos where I was comparing  it with a few Flukes.  One was the 115.  I did not know it was made in China until it arrived and I looked at the packaging.  With it being a little older, I wonder if it will be less robust.       

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on December 11, 2015, 03:48:25 am
When I got the Brymen BM869s, I made a few videos where I was comparing  it with a few Flukes.  One was the 115.  I did not know it was made in China until it arrived and I looked at the packaging.  With it being a little older, I wonder if it will be less robust.     
Will a 115 be next on the bench Joe?
Check to see if it too has that Gawd awful calibration connection like the 17+  :-- , you want to be able to tweak your DMM too, don't you?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 11, 2015, 04:23:40 am
When I got the Brymen BM869s, I made a few videos where I was comparing  it with a few Flukes.  One was the 115.  I did not know it was made in China until it arrived and I looked at the packaging.  With it being a little older, I wonder if it will be less robust.     
Will a 115 be next on the bench Joe?
Check to see if it too has that Gawd awful calibration connection like the 17+  :-- , you want to be able to tweak your DMM too, don't you?
Yes, my plan is to run the 115 to failure next.  If people find it helpful, rather than just running the tests I'll continue to do some sort of mini review of them to at least show how they compare against some of the surviving meters.

As long as the equipment does not drift too much, or the factory has a way to align them in this country, no big deal.  It is sort of funny that the one adjustment the 17B+ has is in the temperature circuit.  And what failed, the temperature circuit.  They knew I was going to need to tweak it. :-DD   

I will give you that the reason the Mastech and AMPROBES are so tight is because I took the time to align them.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 13, 2015, 12:38:20 pm
The Fluke 115, Part 1

https://www.youtube.com/watch?v=cB0K5p7CgtE (https://www.youtube.com/watch?v=cB0K5p7CgtE)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muttley Snickers on December 13, 2015, 01:44:33 pm
Oops..... :palm:.....I haven't yet subscribed but we can soon fix that, a brilliant informative sequence of great videos, many thanks.... :-+

I have a couple of 117s and will need to check them again to see if there was any off mode current draw, I did test them once but cant remember and I religiously pull out the batteries when not in regular use, your 115 appeared to recover once the battery was removed and reinstalled the first time around but it may have been just a coincidence and something else altogether.

Kind regards.... :)

Muttley
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on December 13, 2015, 07:24:07 pm
Hey Joe, I have several people on another forum that want to know the EXACT specs of your HF test that blew the leads off. Specifically, FWHM, source impedance, was it the HV spike only or did it include the AC load as well, etc. Any details you can provide would be great. I have already been told I have an axe to grind because I panned the HF meter  |O
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 13, 2015, 11:42:41 pm
Oops..... :palm:.....I haven't yet subscribed but we can soon fix that, a brilliant informative sequence of great videos, many thanks.... :-+

I have a couple of 117s and will need to check them again to see if there was any off mode current draw, I did test them once but cant remember and I religiously pull out the batteries when not in regular use, your 115 appeared to recover once the battery was removed and reinstalled the first time around but it may have been just a coincidence and something else altogether.

Kind regards.... :)

Muttley

Thanks.   I have no idea what happened with the 115 during the testing.  If I were to guess, I think it caused a latchup condition in the control IC.   I would not be surprised at all if removing the battery is not was what caused it to recover.

To be clear, I wonder if they do not use for example safe state machines and the discharge caused it to go to an undefined state and hang, or if the device when metastable.  :-//   The way it somewhat still worked, I suspect it put it into an undefined state.   


Hey Joe, I have several people on another forum that want to know the EXACT specs of your HF test that blew the leads off. Specifically, FWHM, source impedance, was it the HV spike only or did it include the AC load as well, etc. Any details you can provide would be great. I have already been told I have an axe to grind because I panned the HF meter  |O

 :-DD I saw someone had asked about in the comments for the video as well.   They are always welcome to join the group.  You know what is funny about this?  When someone asked me to run another one, I had cut apart one of the probes from the other  ones to make my shorting stick for the first generator.   You see it in many of the videos.  It was very poorly made.   This made me think, I should run this meter with the leads.   I think this was the only time I really tried the leads that came with any meter.    Part of me was glad I did as it shows just what can happen with poor quality leads.    Imagine some high voltage wire flapping around in front of you!!   

I'm not sure why this would ever be a question.    As I said in the videos where I was making the second generator, I was targeting 400 joules.   I explained how I came up with that number as a goal.   All three generators use 2 ohms.  I pretty much gave up on the higher resistance values after the first rounds of testing.   Photonicinduction would laugh at that amount of energy but it's way higher than the sub 20 I had been using to test the meters.   

What would be fun is to put one on a real generator and see what happens!   Oh yea...... I think Fluke has some videos like that!  :-DD :-DD

At this time I have not added any testing with the line simulator to the spreadsheet.   All of the meters I have been looking at would not have a problem with it (well there is that UNI-T  >:D)

i like the details on the Hz response of the continuity and the hysteresis. +99pts ! :P

Thanks!  It makes a lot more sense to me as well versus just rubbing the leads together. 

The second half of the video is uploading and will be available shortly...
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 14, 2015, 12:15:05 am
The Fluke 115 part 2 of 2
https://www.youtube.com/watch?v=-BOH4bapUnI (https://www.youtube.com/watch?v=-BOH4bapUnI)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 14, 2015, 11:33:46 pm
I was looking at the two Fluke 115s I used for my reviews.   They look the same at a glance.... 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 15, 2015, 11:42:24 am
It's more than the color....   Notice the ratings and serial numbers. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 15, 2015, 11:54:29 am
Both "DESIGNED IN USA" but maybe they changed where they were made and corporate did not want to invest in having to re-certify them.    :-//       
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on December 15, 2015, 12:27:03 pm
Both "DESIGNED IN USA" but maybe they changed where they were made and corporate did not want to invest in having to re-certify them.    :-//     
I think it's possibly because they changed the regulations and they didn't want to change their input v protection to recertify. That would be my guess.

Either way, that is VERY disappointing for Fluke to do.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on December 15, 2015, 04:35:47 pm
Compare the PCBs side by side and check revision numbers.  IMHO, its likely they'll be identical.  Fluke likely dropped certification marks of other agencies to save money; a mark cost about $5,000-10,000 each per year per model in production. 

With IEC specifying standards and worldwide testing agencies harmonized to IEC, one agency mark is good as another effectively, but government entities may be slow to recognize other marks.

In North America, CSA is preferred over UL now, as it costs ~ 1/2 of UL.  Drop UL, no need for both.

VDE and TUV are redundant for the EU market, and can't hurt to put a free CE mark.  So drop at least one.

TUV is recognized in North America, so TUV and CSA are redundant but CSA may not be recognized in the EU.

The 'check ' mark is for AUS/NZ use.

Noticeably absent are marks for sale in PRChina, and Korea.





It's more than the color....   Notice the ratings and serial numbers. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 16, 2015, 01:32:04 am
If Fluke made a meter with the features and battery life of the BM869s, electrical robustness of the 107,  designed and made here in the USA and under 1K, I would be the first in line.   That's coming from someone who would never have owned another Fluke until I started trying to damage them.   :-DD   Hard to believe Fluke would not mark them over money but then again, times change.

Here's the donated Greenlee.   Looks like there are a few positive reviews on it:

http://www.amazon.com/Greenlee-DM-20-Ranging-Digital-Multimeter/dp/B000FRQO6C/ref=sr_1_1?ie=UTF8&qid=1450227983&sr=8-1&keywords=greenlee+dm-20\
 (http://www.amazon.com/Greenlee-DM-20-Ranging-Digital-Multimeter/dp/B000FRQO6C/ref=sr_1_1?ie=UTF8&qid=1450227983&sr=8-1&keywords=greenlee+dm-20\)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on December 16, 2015, 02:09:32 am
If Fluke made a meter with the features and battery life of the BM869s, electrical robustness of the 107,  designed and made here in the USA and under 1K, I would be the first in line.   That's coming from someone who would never have owned another Fluke until I started trying to damage them.   :-DD   Hard to believe Fluke would not mark them over money but then again, times change.

Here's the donated Greenlee.   Looks like there are a few positive reviews on it:

http://www.amazon.com/Greenlee-DM-20-Ranging-Digital-Multimeter/dp/B000FRQO6C/ref=sr_1_1?ie=UTF8&qid=1450227983&sr=8-1&keywords=greenlee+dm-20\
 (http://www.amazon.com/Greenlee-DM-20-Ranging-Digital-Multimeter/dp/B000FRQO6C/ref=sr_1_1?ie=UTF8&qid=1450227983&sr=8-1&keywords=greenlee+dm-20\)

An interesting looking meter, whats the COO?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 16, 2015, 02:28:47 am
An interesting looking meter, whats the COO?

Cost?  I have no idea.  Looks like the next higher up that replaced it is around $30.   I assume it's a rebranded.  Made in China, but looks like they could afford a UL listing. 

What's interesting is that the fuse is still good.   

Will have to test it with their leads.  Last time I tried that with a cheap meter, it did not work out so well for the meter.    :-DD Should be interesting.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on December 16, 2015, 02:53:22 am
An interesting looking meter, whats the COO?

Cost?  I have no idea.  Looks like the next higher up that replaced it is around $30.   I assume it's a rebranded.  Made in China, but looks like they could afford a UL listing. 

What's interesting is that the fuse is still good.   

Will have to test it with their leads.  Last time I tried that with a cheap meter, it did not work out so well for the meter.    :-DD Should be interesting.

COO = Country of Origin (which you answered).

I am intrigued to see a teardown and testing of this meter. It looks VERY different than anything out there. Kinda fat and chunky in a weird way.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ModemHead on December 16, 2015, 04:04:36 am
Here's the donated Greenlee.   Looks like there are a few positive reviews on it:

2000 count manual ranging, with the lowest ACV range being 200V, means the basic design is the same as your average "830" cheapie with a 7106 COB, maybe an extra opamp for continuity tester.  Interesting, I see that Greenlee de-rated the high ACV range down to 300V, most cheapies are marked 500, 600 or even 750V.  And omitted the usual hFE test socket.  Did they beef up the input protection as well?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 16, 2015, 01:15:57 pm
COO = Country of Origin (which you answered).

I am intrigued to see a teardown and testing of this meter. It looks VERY different than anything out there. Kinda fat and chunky in a weird way.

I figured COO = Cost of Ownership.  In the end you had to spell it out anyway.   ROTFLMAO

2000 count manual ranging, with the lowest ACV range being 200V, means the basic design is the same as your average "830" cheapie with a 7106 COB, maybe an extra opamp for continuity tester.  Interesting, I see that Greenlee de-rated the high ACV range down to 300V, most cheapies are marked 500, 600 or even 750V.  And omitted the usual hFE test socket.  Did they beef up the input protection as well?

I looked at the manual last night.  Its available on Greenlee's site.  I saw that 300V max and laughed.   I like the 300 and 200 volt ranges.  :-DD   I assume the 300 was originally marked at the higher level.   

My plan going forward is to follow the same sort of format as the last few videos I made.  So I will go ahead and remove the board so we can see what it looks like before.   Any bets on the input? 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 16, 2015, 01:25:36 pm
Here's the donated Greenlee.   Looks like there are a few positive reviews on it:

That thing looks horrible.  Awful screen. Range switch too small. Captive probes.   :scared:

I predict the insides will be terrible and it will fail on the barbecue-lighter test.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on December 16, 2015, 02:38:42 pm
As a side story, I use DMMs often on metal hulled ships.  AC, even DC, is typically transient heavy enough to kill or severely injure DMMs, and I've experienced in use failures, but not explosions, with non-Fluke DMMs doing a typical measurement.  Fluke DMMs tend to dominate use on steel hulled vessels.  After Joe's test I've rerun some test myself and put the 101 seagoing conditions and its working very well, plus easier to pocket.  Equipment has to be very reliable if depended on and one is in the middle of the Pacific for stretches of time.  I've never seen side by side tests like Joe does here with different brands and models, and it clearly shows what you pay for. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 16, 2015, 02:58:05 pm
As a side story, I use DMMs often on metal hulled ships.  AC, even DC, is typically transient heavy enough to kill or severely injure DMMs, and I've experienced in use failures, but not explosions, with non-Fluke DMMs doing a typical measurement.  Fluke DMMs tend to dominate use on steel hulled vessels.  After Joe's test I've rerun some test myself and put the 101 seagoing conditions and its working very well, plus easier to pocket.  Equipment has to be very reliable if depended on and one is in the middle of the Pacific for stretches of time.  I've never seen side by side tests like Joe does here with different brands and models, and it clearly shows what you pay for.
The Fluke 100 series seems quite unbeatable for reliable, safe, everyday usage (ie. non-EE work).

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on December 16, 2015, 03:19:10 pm
Yes, my 101 does 90% of what I need in the field.  The 10% is mostly modified sine wave converters that are way off on averaging meters then I have to macgyver the measurement.

Joe easily shows Fluke's secret sauce, they will scrimp on functions, but they don't on surge protection even for their cheapest cataloged DMM [ I think as of this writing, its the 101].

The Fluke 100 series seems quite unbeatable for reliable, safe, everyday usage (ie. non-EE work).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 16, 2015, 03:36:13 pm
Joe easily shows Fluke's secret sauce, they will scrimp on functions, but they don't on surge protection even for their cheapest cataloged DMM [ I think as of this writing, its the 101].

Yep. They're ideal for 'electrician' work. They're also only about $43 (delivery included!) so there's no excuse.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 16, 2015, 06:21:02 pm
As a side story, I use DMMs often on metal hulled ships.  AC, even DC, is typically transient heavy enough to kill or severely injure DMMs, and I've experienced in use failures, but not explosions, with non-Fluke DMMs doing a typical measurement. 

This is very interesting.  Could you provide more details about the cause of these transients and have you ever tried to characterize them? 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: saturation on December 16, 2015, 09:16:52 pm
Yes!  Marine electricals need DMMs made for industrial settings.  Electric motors power cranes,lift, tools, equipment and the power inverters, alternators or generators supplying AC or DC are common culprits.  Modern ones start out fine, but they quickly deteriorate from the seaborn environment and start to pollute the surroundings fairly soon.  While the supplies are all isolated in ships noise can be coupled inductively to all the power wirings or radiated, and on older ships deteriorating insulation from accelerated wear from environmental exposure increase their noise potential: UV, hot sunlight mostly.  Common environmental killers are distant lightning strikes traveling on the top of the water column and heavy static from the environment, when in very dry air.  Radios, radar like systems have high pulse demands for power causing a lot of switching transients, if not RF noise in the general area.

Metal hulls act a bit like Faraday cages and help protect from noise, in practice its less that perfect and worst top side, and best when you're deep in the vessel.  Typical civilian vessels are fiberglass and offer less protection other than the conduits.

Note, ships are cleanest when at dock, most of the system could be shut off and many ships get AC from dockside connections, like an RV in a camp.  Its at sea when noise is greatest and need for reliability, highest.  Military ships with electronic warfare gear and carriers are even worse.

More details:

http://www.cedrat.com/fileadmin/user_upload/cedrat_groupe/Publications/Publications/2006/06/en51_Power_Quality_on_Electric_ships_PSCAD.pdf (http://www.cedrat.com/fileadmin/user_upload/cedrat_groupe/Publications/Publications/2006/06/en51_Power_Quality_on_Electric_ships_PSCAD.pdf)


The pdf is a brochure for a simulator of shipboard electrical system but it highlights the issues in more detail.

As a side story, I use DMMs often on metal hulled ships.  AC, even DC, is typically transient heavy enough to kill or severely injure DMMs, and I've experienced in use failures, but not explosions, with non-Fluke DMMs doing a typical measurement. 

This is very interesting.  Could you provide more details about the cause of these transients and have you ever tried to characterize them? 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 16, 2015, 11:17:02 pm
Just finished reading it.  Thanks.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 17, 2015, 03:25:37 am
hi joeqsmith
can i suggest doing a sideshow, to try whipping the surges at some protection components with your gear, the aim is that by modding say the UNI-T with additional tested MOV or TVS, it then passes your surge test ?

Do you have a circuit in mind?  If so, post the schematic and I'll see what I can do.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 17, 2015, 03:27:22 am
So there I was tonight playing with this Greenlee meter and I notice that it appears to has some sort of backlight for the yellow knob.   It only comes on every now and then and I can't find details about it in the manual..   >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 17, 2015, 05:03:26 am
no i dont have circuit in mind. its just an idea because the UNI-T PCB always come with unpopulated MOV. if say by putting in the MOV, and it can stand up to some more surge, it could be good news for some DIY-ers who are interested to mod it but do not know the result for a real surge.

There are a few things you should consider.....

There are many many different MOVs in the world.   I would doubt they put it right across the inputs for example.  So even if you knew the MFG and PN for the MOV, hooking it to the generator is not going to tell you much.   

Even if you traced out that part of the circuit of the meter you are wanting to test, clearances would not be the same if I just threw something together.  If your goal is to test a specific meter with some changes, I think to really know what is going to happen we would use the real meter.   

Next is your statement about "...DIY-ers who are interested to mod it but do not know the result for a real surge."
First, let's talk "real surge".   Let's just assume that the IEC standards represent a real surge.  I have been involved with these tests from time to time.  Believe me, if something goes wrong there it can be a real thrill.   Even my little half cycle line simulator does not come close to the amount of energy we test to.   And believe me, with all the comments people have talked about safety and how the meters have never been shown to be unsafe during my tests, the last thing you want is for someone who has no clue to modify their own meter and then think it would survive these tests or worse, somehow be safe.    None of us want that.   This is why there are real labs that run these tests.

Its fun to look at some of the mods people have done to their handheld meters.  Some of those rat nests would light up on a real test and worse, after cutting holes in the case, may actually come apart.   No thanks...

If the goal is to "harden" the meters front end, I tried to show how to make an attenuator for a meter.  Once again, people started talking about safety, which was never the goal.  It is a good way to protect the meters front end.  That may be a better approach. 

That said, believe me, I know what you are getting at and you are not the first person to ask me about this. My advice is just buy a better meter if you are concerned about it.


Here's the donated Greenlee.   Looks like there are a few positive reviews on it:

That thing looks horrible.  Awful screen. Range switch too small. Captive probes.   :scared:

I predict the insides will be terrible and it will fail on the barbecue-lighter test.



 :-DD :-DD :-DD  You sir are a psychic!!!  I have finished my testing on the Greenlee and hope to have the video and updated spreadsheet in the next day or so.    Now about that backlight feature.....

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 18, 2015, 04:09:52 am
I was looking at a Newport HHM290 meter today.  What caught my eye was it measures inductance.  Then I noticed the two thermocouple inputs plus IR temperature.   Strange that they did not autorange everything.  It make the BM869s look small if that's even possible. 
 
http://www.newport.ca/Pdf/HHM290.pdf (http://www.newport.ca/Pdf/HHM290.pdf)

For those who are interested in knowing how the Greenlee DM-20 held up during my tests, enjoy.

https://www.youtube.com/watch?v=SIQuk0E6wdU&feature=youtu.be (https://www.youtube.com/watch?v=SIQuk0E6wdU&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on December 18, 2015, 03:38:21 pm
I was looking at a Newport HHM290 meter today.  What caught my eye was it measures inductance.  Then I noticed the two thermocouple inputs plus IR temperature.   Strange that they did not autorange everything.  It make the BM869s look small if that's even possible. 
 
http://www.newport.ca/Pdf/HHM290.pdf (http://www.newport.ca/Pdf/HHM290.pdf)

For those who are interested in knowing how the Greenlee DM-20 held up during my tests, enjoy.

https://www.youtube.com/watch?v=SIQuk0E6wdU&feature=youtu.be (https://www.youtube.com/watch?v=SIQuk0E6wdU&feature=youtu.be)

Proved to be an interesting test.

SL is the circuit board manufacturer, according to UL the E234156 (http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=ZPMV2.E234156&ccnshorttitle=Wiring,+Printed+-+Component&objid=1076390468&cfgid=1073741824&version=versionless&parent_id=1073814637&sequence=1) references "SHEN ZHEN SUN & LYNN CIRCUITS CO LTD". That would be your SL. Unfortunately, they are just the board maker, not the designer of the instrument. 94V-0 is a safety marking related to flammability (or lack thereof) if I remember correctly.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 19, 2015, 11:52:55 am
Good info Pedro.   It's just a guess that it was re-branded. 

I was a bit surprised by the amount of sparks that came out of it.  I did not mention it during the video but I did check the leads after the last test and they were fine.  Held up better than the HF meter's leads.   

It would be good to know if the meter had a problem.  The continuity test threshold being so high and that the diode check did not work, I suspect there was a problem with the source.  The original owner told me he used used it for a volt meter only, so I doubt very much that these features are something that was ever used.   May have been bad from the factory.

The spreadsheet has been updated to include this meter.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on December 21, 2015, 06:50:25 am
Joe, after downloading your spreadsheet, it is not clear just what each of the cell pass/fails represent.  :-//
Does it need a tweak or must we refer to your vids to understand what each test is?

Members often ask of DMM recommendations, must they watch all your vids?
Maybe a short further vid in the OP to just explain your methodology and spreadsheet results.

Can I also say it seems obvious (at least to me) that the thread title has many overlook the excellent work you have done, but maybe not so with the addition of DMM in the title.  :-\

Tell me to F off if you must, it is YOUR thread.  ;)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 21, 2015, 07:20:18 am
Joe, after downloading your spreadsheet, it is not clear just what each of the cell pass/fails represent.  :-//

"Fail" = Magic smoke escaped at the specified voltage.

Members often ask of DMM recommendations, must they watch all your vids?

You could try watching one of them...  :-//

PS: They're not 'recommendations'. It only measures one tiny aspect of a multimeter (resistance to sparks).
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on December 21, 2015, 08:25:08 am
Joe, after downloading your spreadsheet, it is not clear just what each of the cell pass/fails represent.  :-//

"Fail" = Magic smoke escaped at the specified voltage.

Members often ask of DMM recommendations, must they watch all your vids?

You could try watching one of them...  :-//

PS: They're not 'recommendations'. It only measures one tiny aspect of a multimeter (resistance to sparks).
|O  :palm:
When I opened the spreadsheet FIRST time the Column titles DID NOT appear, hence the reason for my post.
All good now.  :-+

I've watched them ALL.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 21, 2015, 09:17:18 am
|O  :palm:
When I opened the spreadsheet FIRST time the Column titles DID NOT appear, hence the reason for my post.
All good now.  :-+

 :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 21, 2015, 03:32:34 pm
 :-DD   Glad you figured it out. 

I will be the first to admit there may be a better way to present the data in the spreadsheet.    If anyone has a way to format it that they feel would make things more clear to the reader, feel free to post it.   I am not at all apposed to changing it.

I had though about moving the original round I tests to it's own page so the main page just has the format that I plan to use moving forward.

Can I also say it seems obvious (at least to me) that the thread title has many overlook the excellent work you have done, but maybe not so with the addition of DMM in the title.  :-\
This has came up from time to time but no one has offered what they feel is a better suited title. 


PS: They're not 'recommendations'. It only measures one tiny aspect of a multimeter (resistance to sparks).

One?

1) Continuity, short detection resistance
2) Continuity, open detection resistance
3) Continuity, short circuit current
4) Continuity, open circuit voltage
5) Continuity, max frequency using a 50% duty cycle before meter misses beats
6) Continuity, min pulse width the meter can detect
7) ESD, 5 +/- transients in each mode using a piezo grill ignitor
8) DC withstand voltage, meter is supplied its maximum specified DC voltage, sometimes higher  :-DD
9) 220 VAC line, meter is supplied with a full wave rectified 220V signal with the mode switch being rotated
10) Low voltage low energy surge test, up to 5KV 100us FWHH 2 ohm source, limited to less than 20J
11) High voltage low energy surge test, up to 12KV 50us FWHH 2 ohm source, limited to less than 20J

If I stay with the current format, there are other tests going on as well like basic accuracy, comparing them with other meters in their class or price range.   I showed the NCV feature of the UT139C for example.   If I continue to test meters, I am sure the test methods will improve along with the tests performed.     

And if that is not enough, now we get to see what can happen when some of these crappy meters breakdown with a higher energy source attached.  It does not answer the question if a meter is safe or not but for the people who post that the meters were not shown to be unsafe during the tests at sub 20 joules, it does give viewers some indication of what a small amount of energy could do to a meter.   

Just an FYI, testing one meter like the 115 where it survives takes about 10 hours not including the editing time.   :palm:   The Greenlee still took about 8 hours from start to finish. 

There are many tests others have done that really do not interest me.  Two tests I would like to run are DC temperature drift and RF susceptibility.  Both way outside of what I could do at home.   

This may help you with your counting skills
https://www.youtube.com/watch?v=UtiMNzGAl6w (https://www.youtube.com/watch?v=UtiMNzGAl6w)

 :-DD :-DD :-DD :-DD :-DD :-DD :-DD :-DD
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on December 21, 2015, 06:47:10 pm
Joe, I thought just the addition of "DMM" would enable more hits from a forum search:

Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld DMM surge tests.

Anyway, I'll butt out now, please carry on with what history will show as magnificent work.  :-+
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 21, 2015, 07:43:19 pm
Joe, I thought just the addition of "DMM" would enable more hits from a forum search:

Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld DMM surge tests.

Anyway, I'll butt out now, please carry on with what history will show as magnificent work.  :-+

 :-+

One member mentioned they could not read the entire title due to screen wraps.  I think I made it even longer when I added the DMM part.   We call that being customer led.  :-DD

A few people have asked about why it's not sticky and the fact that it is not I believe is the answer to how it is perceived.

Consider that even if the meters were being supplied to me for free (which thanks to 5ky / TechnologyCatalyst many were), they can not be resold after they are tested and have no value.  I would not even risk giving the working ones away after they have been stressed. 

So believe me, this has never been about making a profit!  :-DD   Even if I turned on the youtube ads, maybe I could buy a new Harbor Freight free meter?  :-DD   Its more been interesting for me to see just how wide of a spectrum there is in the robustness of the meters, even within the same brand.   

So don't look for it to go down in the history books unless you're looking on the basement floor in a back corner somewhere.  :-DD 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 26, 2015, 09:49:14 pm
After six years of use, my Mastech MS9508 / Cen-tech P37772 LCD was starting to become intermittent. 

Notice that the LCD is starting to pop out.  The On and Hold buttons are letting some photons escape.  Sparks are coming from the transistor test socket.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: tautech on December 26, 2015, 10:32:41 pm
After six years of use, my Mastech MS9508 / Cen-tech P37772 LCD was starting to become intermittent. 

Notice that the LCD is starting to pop out.  The On and Hold buttons are letting some photons escape.  Sparks are coming from the transistor test socket.
:-DD
No holidays for you and your surge tester.  >:D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 27, 2015, 01:22:12 am
:-DD
No holidays for you and your surge tester.  >:D

Consider the video a gift.

It's amazing just how complicated this meter is.  I got a lot of use out of this meter over the last six years and if the display wasn't becoming intermittent again,  I would have kept using it.   

It's a manual range meter and would take a fair amount of time to run a full test, so instead I just did a quick teardown, functional and hit it with the half cycle line simulator.   

What meter to fun first in 2016?   Would like to see that Keysight GDT protection in action

https://www.youtube.com/watch?v=NKgK8qbuREk&feature=youtu.be (https://www.youtube.com/watch?v=NKgK8qbuREk&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: rsjsouza on December 27, 2015, 03:00:27 am
joe, thanks for sharing - great christmas gift. One small detail that may increase your audience: on the video title, change the model of the meter from MS9508 to M9508.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Stupid Beard on December 27, 2015, 10:17:17 am
What meter to fun first in 2016?   Would like to see that Keysight GDT protection in action

Maybe not the first meter, but it'd be nice to see a BM257 run at some point. You've run a lot of lower end Flukes and compared them to your BM869 as a comparison to Brymen meters, but it seems to me that a BM257 or similar would be a fairer comparison in terms of price range / size / etc.

Thanks for the videos. I've been watching them from the beginning and it will be interesting to see what survives in 2016.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on December 27, 2015, 01:24:33 pm
I just was thinking that instead of blowiing up a bunch of more meters, why not run a video on the protection devices that can be found inside. Run a PTC or two, some MOVs, gas discharge tubes, etc. This would give easy subjects to video, and some fun fireworks perhaps. It would also be much cheaper and easier to video. This would help illustrate the actual safety of the safety devices themselves.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on December 27, 2015, 02:02:34 pm
I have a feeling the larger GDT devices will survive the test, but the other protective devices will certainly fail. The more common larger GDT devices will absorb enough energy to clamp a spike down to 1kV even if the spike is a direct lightning hit. The traces will vapourise, but the GDT will still be there unbroken in the carnage. Seen that in plenty of telecoms applications, where you find the green module blackened and burned, with nothing left of the incoming wiring, the IDC Krone socket, the PCB holding the GDT units or the earth wire, unless you used 10mm cable for it. About 10% chance the PBX after it has survived unscathed, they generally blow all the line cards, power supply and any extension card that ran into the incoming frame. The phones however typically will survive, unless they were in use when the lightning hit.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 27, 2015, 05:22:21 pm
What meter to fun first in 2016?   Would like to see that Keysight GDT protection in action

Maybe not the first meter, but it'd be nice to see a BM257 run at some point. You've run a lot of lower end Flukes and compared them to your BM869 as a comparison to Brymen meters, but it seems to me that a BM257 or similar would be a fairer comparison in terms of price range / size / etc.

Thanks for the videos. I've been watching them from the beginning and it will be interesting to see what survives in 2016.

Brymen makes some nice looking meters.   I looked at the manual for this one.   It's not very expensive.     

I have a feeling the larger GDT devices will survive the test, but the other protective devices will certainly fail. The more common larger GDT devices will absorb enough energy to clamp a spike down to 1kV even if the spike is a direct lightning hit. The traces will vapourise, but the GDT will still be there unbroken in the carnage. Seen that in plenty of telecoms applications, where you find the green module blackened and burned, with nothing left of the incoming wiring, the IDC Krone socket, the PCB holding the GDT units or the earth wire, unless you used 10mm cable for it. About 10% chance the PBX after it has survived unscathed, they generally blow all the line cards, power supply and any extension card that ran into the incoming frame. The phones however typically will survive, unless they were in use when the lightning hit.

Looking at the Keysight, if the waveform has a fast leading edge, will it damage other components before the GDT responds?  I would have expected to see something like small MOVs or transorbs on the Keysight meter to handle this.  Maybe they are there or maybe they are not needed.   The other thing I don't like is how they latch until the energy dissipates.   In Dave's video (again hard to tell for sure) looked like they have two stages.   If the first R fails short and the GDT is tuned on we now have a very low impedance path.  All that energy from the line is would now be going through the meter and leads.   Once it starts to breakdown, seems like it could go bad fast.   Normally when I have damaged MOVs with a surge (not my toy setup) they will short, then open up.   :-//     Would really like to see a schematic of the front end and run it against the other meters. 

Keysight may not care if the meter is damaged as long as it does not present a hazard.   Personally, I would want the meter to survive the 6KV like all of the low cost Flukes, the Brymen BM769s and 5KYs Radioshack.   

I just was thinking that instead of blowiing up a bunch of more meters, why not run a video on the protection devices that can be found inside. Run a PTC or two, some MOVs, gas discharge tubes, etc. This would give easy subjects to video, and some fun fireworks perhaps. It would also be much cheaper and easier to video. This would help illustrate the actual safety of the safety devices themselves.


I am still open for ideas.   My response is below.   

no i dont have circuit in mind. its just an idea because the UNI-T PCB always come with unpopulated MOV. if say by putting in the MOV, and it can stand up to some more surge, it could be good news for some DIY-ers who are interested to mod it but do not know the result for a real surge.

There are a few things you should consider.....

There are many many different MOVs in the world.   I would doubt they put it right across the inputs for example.  So even if you knew the MFG and PN for the MOV, hooking it to the generator is not going to tell you much.   

Even if you traced out that part of the circuit of the meter you are wanting to test, clearances would not be the same if I just threw something together.  If your goal is to test a specific meter with some changes, I think to really know what is going to happen we would use the real meter.   

Next is your statement about "...DIY-ers who are interested to mod it but do not know the result for a real surge."
First, let's talk "real surge".   Let's just assume that the IEC standards represent a real surge.  I have been involved with these tests from time to time.  Believe me, if something goes wrong there it can be a real thrill.   Even my little half cycle line simulator does not come close to the amount of energy we test to.   And believe me, with all the comments people have talked about safety and how the meters have never been shown to be unsafe during my tests, the last thing you want is for someone who has no clue to modify their own meter and then think it would survive these tests or worse, somehow be safe.    None of us want that.   This is why there are real labs that run these tests.

Its fun to look at some of the mods people have done to their handheld meters.  Some of those rat nests would light up on a real test and worse, after cutting holes in the case, may actually come apart.   No thanks...

If the goal is to "harden" the meters front end, I tried to show how to make an attenuator for a meter.  Once again, people started talking about safety, which was never the goal.  It is a good way to protect the meters front end.  That may be a better approach. 

That said, believe me, I know what you are getting at and you are not the first person to ask me about this. My advice is just buy a better meter if you are concerned about it.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on December 27, 2015, 06:01:21 pm
A little info on GDT and usage and turn on.

http://www.citel.us/gas_discharge_tubes_overview.html (http://www.citel.us/gas_discharge_tubes_overview.html)

Littelfuse datasheet, they are probably the devices installed.

http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_gdt_catalog.pdf.pdf (http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_gdt_catalog.pdf.pdf)

they are rated to handle a pulse with a risetime of 1kV/us, so turn on is pretty fast. Failure is by going open circuit on the 2 terminal devices, though you do get safety ones that have a shorting bar that fails the device as a short circuit when it is ruptured.

Page 10 shows that it pretty much is turning on after around 300ns of the transient being applied, most of this probably due to lead inductance. They tend to stay on until the voltage drops below the holding voltage of around 140V, though they can easily clamp at over 1kV on a high energy pulse limiting the downstream side to that. Probably that is why they use 2 in series, so the voltage is clamped hard by the second stage to the breakover voltage of the second device.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 27, 2015, 07:28:46 pm
A little info on GDT and usage and turn on.

http://www.citel.us/gas_discharge_tubes_overview.html (http://www.citel.us/gas_discharge_tubes_overview.html)

Littelfuse datasheet, they are probably the devices installed.

http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_gdt_catalog.pdf.pdf (http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_gdt_catalog.pdf.pdf)

they are rated to handle a pulse with a risetime of 1kV/us, so turn on is pretty fast. Failure is by going open circuit on the 2 terminal devices, though you do get safety ones that have a shorting bar that fails the device as a short circuit when it is ruptured.

Page 10 shows that it pretty much is turning on after around 300ns of the transient being applied, most of this probably due to lead inductance. They tend to stay on until the voltage drops below the holding voltage of around 140V, though they can easily clamp at over 1kV on a high energy pulse limiting the downstream side to that. Probably that is why they use 2 in series, so the voltage is clamped hard by the second stage to the breakover voltage of the second device.
:-+

Can't imagine having a GDT directly across the inputs of a handheld.   While many devices are rated to handle the surge test, you would need to look at the whole system not just one component.   In Dave's video on the Keysight meter, it looks like they have it in the divider as you would expect.    I have no idea what parts they used.  They may switch at under 100 volts for all I know.   While a  few hundred ns may not seem like a lot of time, consider what it takes to protect the down stream circuits.   One thing the GDTs have going for them is very low capacitance.   

While you are doing your research, you may want to have a look at the Bourns application notes as well for GDTs.  These are pretty good from what I remember.   

This paper gives some general information on protection. 
http://www.onsemi.com/pub_link/Collateral/TND335-D.PDF (http://www.onsemi.com/pub_link/Collateral/TND335-D.PDF)

Looking at the meters I have tested, the one thing you can't count on is the PCB.  I have seen a lot of what I would consider unintentional spark gaps in the layouts.  :-DD   Looking at 5ky's Innova, I doubt they ever thought about clearance from the circuitry on the PCB to the shield.   But, it seems like it could be important.   :-DD

https://www.youtube.com/watch?feature=player_detailpage&v=3fYVaXz8lVk#t=254 (https://www.youtube.com/watch?feature=player_detailpage&v=3fYVaXz8lVk#t=254)

This was another one of 5ky's meters where the PCB was doing a very good job protecting some of the circuitry while I was testing at lower energy levels.   
https://www.youtube.com/watch?feature=player_detailpage&v=9ii55eHfUWY#t=378 (https://www.youtube.com/watch?feature=player_detailpage&v=9ii55eHfUWY#t=378)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on December 27, 2015, 08:22:44 pm
The series resistance on the input does look like it will at least attenuate the pulse, though the survival of the resistor is not guaranteed, so it has a blast shield to keep the pieces more or less together. Then they cascade that again so it is likely it will safely absorb the pulse without blowing up, though the chances of it surviving are not that good it will at least absorb the test pulse. Low capacitance is a major advantage over a MOV, and the residual capacitance will likely help as well.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on December 27, 2015, 10:12:17 pm
PS: They're not 'recommendations'. It only measures one tiny aspect of a multimeter (resistance to sparks).

One?

OK, more than one...  :-[
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 27, 2015, 10:28:10 pm
The series resistance on the input does look like it will at least attenuate the pulse, though the survival of the resistor is not guaranteed, so it has a blast shield to keep the pieces more or less together. Then they cascade that again so it is likely it will safely absorb the pulse without blowing up, though the chances of it surviving are not that good it will at least absorb the test pulse. Low capacitance is a major advantage over a MOV, and the residual capacitance will likely help as well.

Agree, it has to help.  At least it will limit the current.  I would have expected that second stage to have a small MOV.  My guess is they have some other clamps further down the chain to protect the sensitive parts.   

I thought about getting their low end U1232A.  It's CAT III 600 and I would hope would survive at least as well as the Brymen.  When you look at this review, they have some small package GDTs in there.   From all of my tests I have not seen an MOV fail however, some of the PTCs and in rare cases the high voltage resistors have.
I doubt these smaller package GDTs would fail.  My concern would be ICs, diodes, transistors that are down stream from it.

https://www.youtube.com/watch?feature=player_detailpage&v=RYFlHDNA1aA#t=1040 (https://www.youtube.com/watch?feature=player_detailpage&v=RYFlHDNA1aA#t=1040)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 27, 2015, 10:33:28 pm
PS: They're not 'recommendations'. It only measures one tiny aspect of a multimeter (resistance to sparks).

One?

OK, more than one...  :-[

Just having a little fun with you.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 31, 2015, 12:55:50 am
Looking closer at Dave's video, I am not sure what the GDTs they used are.  Appear to be marked 2000 1411.  Littlefuse has a SL1411A series but they are not rated for the sort of voltage needed.  They also don't use blue lettering on white from what I have seen.   Maybe it's custom.   2000 maybe a 2KV breakdown.  This would be in the  ballpark.   Dave did a video showing a insulation tester.  He could use that to at least determine where the tube fires.   

Looks like two separate circuits.  Both use an R, PTC, GDT.   Makes sense.   Would really like to have some values for the R and PTC as well.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on December 31, 2015, 11:49:55 am
Video showing a simple protection circuit based on a production meter using a R, PTC and MOV.    The MOV is then replaced with a GDT.   

https://www.youtube.com/watch?v=wYCGnYglRjY (https://www.youtube.com/watch?v=wYCGnYglRjY)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: SeanB on December 31, 2015, 12:36:08 pm
I would guess they put in some secondary protection, to handle the initial pulse and either clip it using a series resistor further down, with a SMD MOV that is going to handle the limited energy easily, or a simple diode clamp to either a power rail or a zener clamp. Once the spike has been clamped the residual low voltage will be easy to handle.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 01, 2016, 01:45:06 am
Every meter I have looked at that has survived has some type of down stream protection.   With the Keysight meter,   we don't know what the entire circuit is nor do we know how it would stack up against all of the other meters.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 04, 2016, 12:18:21 am
http://www.amazon.com/Morris-59050Vage-Continuity-Tester-12-300V/dp/B005BH6HRM (http://www.amazon.com/Morris-59050Vage-Continuity-Tester-12-300V/dp/B005BH6HRM)

So your touching the side metal contact with your body and jamming it into a live circuit? 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on January 04, 2016, 12:31:48 am
Yup, just like those neon lamp live circuit testers.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muttley Snickers on January 04, 2016, 01:08:17 am
I see an opening and excuse to post these pictures, no teardown was required as it seemed to be an incorporated feature..... :palm:

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 04, 2016, 02:01:57 am
I see an opening and excuse to post these pictures, no teardown was required as it seemed to be an incorporated feature..... :palm:
  Nice!   I bet where the leads solder in would jump.  Maybe if we were lucky, it would go from the red trace to the neon bulb first, then to the black for some added excitement.    :-DD     Then the leads look like they would light up.   

Sound like Lightages has one that uses the humans body to complete the circuit rather than the leads.  Any pictures of this one?

The one I have is marked P-85.  Its rated for 12 - 440 volts AC/DC.   The Morris Products 59050  looks like it and is rated for 440 as well.   

It uses a couple of A76 button batteries.  No power switch.   It detects continuity around 6Meg.  Solid on at 2Meg.  Short circuit current is about 500nA.   If you supply 220VRMS to the across the inputs, the current is about 4.9uA   I tried the piezo grill starter then maxed out the new generator on it but it would not breakdown.   :--  That was with nothing in series.     So I used the old generator set to 12KV and it still works.     

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 04, 2016, 06:01:50 pm
While looking for something with neon bulbs that goes through the human body, I came across this UNI-T CAT IV 600V rated and another banned member.    :-DD 

Could this be the 1st UNI-T that can actually survive on the new generator?   I think we will find out..
https://www.eevblog.com/forum/testgear/%28-product-review-%29-uni-t-ut15c-volt-stick-ip65-cat-iv-600v/ (https://www.eevblog.com/forum/testgear/%28-product-review-%29-uni-t-ut15c-volt-stick-ip65-cat-iv-600v/)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 05, 2016, 01:23:13 am
I had been asked about running a Vichy VC99. Unless anyone is aware of a Vichy meter that is CAT III 600 rated, I can't see a reason to try one.  I would need to change the impedance and have a new section just for CAT II class or just run it with the 2 ohm source.  The CAT III meters have a hard enough time surviving. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 08, 2016, 02:33:30 am
2016 is starting out on a good note.  A new camera has been added to the mix.    A GGT (glass gas discharge tube) has been added to the test jig.   Will it survive the half cycle line test?  Will it even survive the basic test?  Sure looks pretty delicate. 

The first of three new meters arrived today.  Hint, it's a brand I have never ran,  costs more than a shot of Dewars 18 year old scotch at the bar,  uses gas discharge tubes and you know the plan is to see what it takes to damage it. 

So stay tuned. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: fanOfeeDIY on January 08, 2016, 03:36:15 am
So stay tuned.

I will. :)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 13, 2016, 04:16:52 am
Finally trying out the new camera.  My plan is to make up my own opto-coupled trigger cable that will be driven from the transient generator.   To start, I plan to use the signal generator to output a burst of 1KHz pulses into a counter.  The signal generator's trigger out will trigger the camera that will be pointed at the counter.  Then I should be able to determine the trigger jigger and latency.     

This video shows a glass type gas discharge tube at low speed.  Then I setup the counter at 1KHz and recorded at 240 and 960 fps.  Looks like it can almost keep up at 960 as expected.   Picture looks pretty poor.   Guessing it's an operator problem...

https://www.youtube.com/watch?v=rXPnqfkgAzo&feature=youtu.be (https://www.youtube.com/watch?v=rXPnqfkgAzo&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Stupid Beard on January 13, 2016, 05:02:57 am
This video shows a glass type gas discharge tube at low speed.  Then I setup the counter at 1KHz and recorded at 240 and 960 fps.  Looks like it can almost keep up at 960 as expected.   Picture looks pretty poor.   Guessing it's an operator problem...

The picture quality issue might be insufficient light. You generally need a lot more light at faster frame rates. I am by no means knowledgeable in that area but that's what it looked like to me.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 16, 2016, 03:36:58 am
This video shows a glass type gas discharge tube at low speed.  Then I setup the counter at 1KHz and recorded at 240 and 960 fps.  Looks like it can almost keep up at 960 as expected.   Picture looks pretty poor.   Guessing it's an operator problem...

The picture quality issue might be insufficient light. You generally need a lot more light at faster frame rates. I am by no means knowledgeable in that area but that's what it looked like to me.

I am guessing you are right.  The old Cannon I use will get real grainy like this even with stills in low light.   The parts to make the trigger for the camera are now all on order.  I had not realized the mini-USB they use is actually a 10-pin until after I had ordered some standard 5 pin ones.    But the two connectors for the transient generator are here so I can get started making changes to that.   One connector will be a standard 50 ohm output, the other will be an isolated type for the camera.   

In retrospect, attempting to build the generator on old technology was not the brightest idea I have had.   There are about 50 bytes if code space left and no I/O pins to make this programmable trigger.   :palm:   

I have a 22V10 on the board with one unused input that I plan to use to make a multiplexer with a few of the other signals and hope to somehow cram it all in there.   

The other two meters I wanted to run also arrived.  Lots to do.....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 17, 2016, 03:05:24 am
FFE7 to FFEF is still free....   :-DD    Just to be clear, the ROM starts at F800, or 2K total.   

I ended up putting two trigger outputs on the generator.  One is a programmable pre-trigger that will drive the high speed camera, the other is at the time the transient is fired.   Both are just 5V 50 ohm outputs.  I'll make a separate circuit for the camera. 

trigger1: two additional BNCs for the pre-trigger and trigger
trigger2: added pre-trigger  to display, shown at 200ms
trigger3: trigger outputs.   bottom trace rising edge is the pre-trigger.  200ms to trigger rising edge (top trace) 

Joined a camera forum and asked about the Sony's remote.   May have to modify the camera to make this work.   :palm:   Hope to have the Sony remote and a few other parts next week and I can start playing with it. 


01506                         *  INVALID INTERRUPT REQUIESTED
01507                         *
01508  A ffe6 3b              INVALID_IRQ RTI         

M6801 Portable Cross Assembler  0.05  Page 31
 Sat Jan 16 20:16:13 2016 
Options - MD,MC,NOG,NOU,W,NOMEX,CL,FMT,O
 
LINE   S PC   OPCO OPERANDS S LABEL    MNEMO OPERANDS COMMENT
01509                         *
01510                         * INTERRUPT VECTORS
01511                         *
01512  A fff0                          ORG   IRQ_VEC  FFF0 - ROM
01513  A fff0      ffe6     A          FDB   INVALID_IRQ SCI
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 19, 2016, 12:53:16 am
Strange UNI-T ad where they go after Fluke. 

https://www.youtube.com/watch?v=7fFjiLU5bF0 (https://www.youtube.com/watch?v=7fFjiLU5bF0)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: PedroDaGr8 on January 19, 2016, 04:06:33 am
Strange UNI-T ad where they go after Fluke. 

https://www.youtube.com/watch?v=7fFjiLU5bF0 (https://www.youtube.com/watch?v=7fFjiLU5bF0)

Wow, that is truly truly weird.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 19, 2016, 04:30:52 am
I need to drill a few more holes in my custom made camera mount.      The last parts for the trigger should be in tomorrow.  Won't be long now.....

In the mean time, finally some fire and smoke....  In this video, I put the meter proto board the test again and capture the results with the new camera.   

https://www.youtube.com/watch?v=bUSIf3QOEA8 (https://www.youtube.com/watch?v=bUSIf3QOEA8)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 21, 2016, 01:35:39 am
Finished up the remote and tested the camera's trigger delay.   

https://www.youtube.com/watch?v=jNF-j2B8caU&feature=youtu.be (https://www.youtube.com/watch?v=jNF-j2B8caU&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 21, 2016, 04:35:53 am
And finally, the new camera with modified remote is connected to the surge generator for the very first auto trigger....   And it works!!!  :phew:

I'm thinking it's time to look at a meter with some GDTs in it!  >:D

https://www.youtube.com/watch?v=ms5OIBnQ_ig (https://www.youtube.com/watch?v=ms5OIBnQ_ig)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 23, 2016, 01:24:08 am
One of the meters I wanted to run was the UNI-T UT15C VoltStick.   The UNI-Ts have been some of the worst meters I have looked at and this one in particular has a CAT IV 600 rating and it basically just reads voltage so you would think it would be very robust.

There is a review of it on this site
https://www.eevblog.com/forum/testgear/%28-product-review-%29-uni-t-ut15c-volt-stick-ip65-cat-iv-600v/ (https://www.eevblog.com/forum/testgear/%28-product-review-%29-uni-t-ut15c-volt-stick-ip65-cat-iv-600v/)

Will it overthrow 5Ky's Fluke 107??? 

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 23, 2016, 09:44:31 am
I like the picture they used for the packaging of the UT15C.  Hope you enjoy the review.

https://www.youtube.com/watch?v=i8pRlvgJw-o (https://www.youtube.com/watch?v=i8pRlvgJw-o)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on January 23, 2016, 01:01:36 pm
I thought the continuity test would be the failure point but it's the only thing that survived.  :-//

Quite a surprising amount of components inside it for such limited/low-accuracy functionality.  :popcorn:

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 23, 2016, 10:20:39 pm
I thought the continuity test would be the failure point but it's the only thing that survived.  :-//

Quite a surprising amount of components inside it for such limited/low-accuracy functionality.  :popcorn:



Hey there Mr Fungus.   I really thought this was going to be the first UNI-T that survived beyond 5ky's Fluke 107 or at least hung in there with the low end Flukes.   Mainly because of the CAT IV 600V rating on it and the it appears to be purpose built to measure  AC line voltage.    There were no reviews I could find that were in English so I thought I would run one.   I agree, it is very complex for what it does.   

I have updated the spreadsheet to include the UT15C.  No other changes were made.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ehuesman on January 24, 2016, 06:36:23 pm
Hi Joe,

Your videos and this thread have been extremely helpful in my decision making about buying a budget multi-purpose multimeter, so thank you very much for the work you put in. I've posted my own thread concerning a couple models I've narrowed it down to, based in large part on your information. My question here has to do with your spreadsheet attached to this thread. Is there a way to annotate or color-code the headings so that I know the CAT rating each test applies to? Meaning, if one of the tests was "3.0KV 2 ohm", which CAT protection level would that fall under? I can look at the spreadsheet now and see where certain models failed, but I can't tell if the failure was before or after their supposed CAT rating (unless I'm missing something, which is totally possible, and in that case I apologize).

I'm specifically interested in the two Amprobe models and the Greenlee model you tested. The AM-510 and AM-530 are both supposed to be CAT III and the DM-20 was labeled a CAT II.

Thanks in advance!

- Eric
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 24, 2016, 09:21:11 pm
Hi Joe,

Your videos and this thread have been extremely helpful in my decision making about buying a budget multi-purpose multimeter, so thank you very much for the work you put in. I've posted my own thread concerning a couple models I've narrowed it down to, based in large part on your information. My question here has to do with your spreadsheet attached to this thread. Is there a way to annotate or color-code the headings so that I know the CAT rating each test applies to? Meaning, if one of the tests was "3.0KV 2 ohm", which CAT protection level would that fall under? I can look at the spreadsheet now and see where certain models failed, but I can't tell if the failure was before or after their supposed CAT rating (unless I'm missing something, which is totally possible, and in that case I apologize).

I'm specifically interested in the two Amprobe models and the Greenlee model you tested. The AM-510 and AM-530 are both supposed to be CAT III and the DM-20 was labeled a CAT II.

Thanks in advance!

- Eric


Eric,  I'm glad you found the videos helpful.   Yes, I can easily color code the spreadsheet to show the CAT rating each test applies to.   In every case, THEY DON'T!!   :-DD   
There are two big differences.   Because IEC is concerned with safety and I am only concerned with robustness, the meters NEVER see the energy levels they could if tested to the IEC standard.      The real generators will meet both the open and short circuit waveform requirements.   I limit the shorted energy to less than 20 Joules. 

For tests below 6KV, I now test with a open circuit, 100us FWHH.   6KV and above are now ran with a 50us FWHH, more like the IEC standard.     

Now........  Consider if the meter would not break over and had a 10M input.  It will not matter what the short circuit waveform looks like.    It's hard to push a few thousand amps through an open.    This is only going to come into play when something goes wrong.

I have not been buying meters that are lower than CAT III.   So I always test with a 2 ohm source now.   

For the 2nd edition of the standard, CAT III & IV 1.2/50us open waveform peaks are:
CAT III 50, 800 V peak
CAT III 100, 1500 V peak
CAT III 150, 2500 V peak
CAT III 300, 4000 V peak
CAT III 600, 6000 V peak
CAT III 1000, 8000 V peak
 
CAT IV 50, 1500 V peak
CAT IV 100, 2500 V peak
CAT IV 150, 4000 V peak
CAT IV 300, 6000 V peak
CAT IV 600, 8000 V peak
CAT IV 1000, 12000 V peak

A meter that is rated to CAT III 1000 does not mean it is also rated to CAT IV 600!!!!   So don't read more into this than what it is!

Obviously, I have been playing around with some higher energy levels but nothing that has been added to the spreadsheet and even then, these energy levels are still far below what we would test for with the IEC standards.   

Hope this helps.


   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: ehuesman on January 24, 2016, 09:58:29 pm
I'm sure your answer would be helpful if I had the slightest clue as to what you were talking about, lol. I should've paid more attention to what you were saying in your videos. Based on some of your remarks and the title of the thread, I made the assumption (I know...) you were checking the multimeters against their claimed safety standard. I don't understand what you just told me, but I do understand my assumption was wrong.  |O

Either way, your testing was still a good guide for me and definitely was crucial in my decision to only go with independently tested models, so thank you.
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 24, 2016, 10:51:29 pm
 :-DD  Yea, sorry about that.  I know my videos tend to be dry and my monotone voice can put you to sleep.   So I won't blame you your not following along real close.   

I am currently playing with my first ever Keysight handheld meter.  Planning on a two part video like the last few.   More of a review.   

Maybe Keysight with it's fancy gas discharge tubes will dethrone the Flukes...   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 27, 2016, 04:10:46 am
I am amazed how susceptible some of the handheld meters are to RF.   You would think they would be stable with a 10v/m h/v gigish.   Somehow I doubt it. 

Funny, I have never had the need to put a meter in a chamber.  Any of you ever look into this? 

Almost forgot, the first half of my Keysight meter review is uploading now for those of you interested in a little GDT action.  So stay tuned....

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 28, 2016, 01:00:27 am
Part 1 of the Keysight U1231A.  I have not yet ran any of the surge transients yet and am hoping to get to it this weekend.   

https://www.youtube.com/watch?v=gjYPyuS8uhM (https://www.youtube.com/watch?v=gjYPyuS8uhM)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 30, 2016, 04:45:39 pm
That was quick.   :box:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Lightages on January 30, 2016, 07:51:35 pm
That was quick.   :box:

 :-//
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 30, 2016, 08:44:36 pm
That was quick.   :box:

 :-//

From above:
Quote
I have not yet ran any of the surge transients yet and am hoping to get to it this weekend.   
The weekend is here.  Can I interest you in a slightly used Keysight meter?
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 30, 2016, 11:46:47 pm
Keysight's gas discharge tubes in action. 
https://www.youtube.com/watch?v=lE5CKaLzvqU (https://www.youtube.com/watch?v=lE5CKaLzvqU)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on January 31, 2016, 12:45:49 am
As a side note, I downloaded the datasheet for the controller IC and then tacked a couple of leads to the supply pins.   The device will pull about 60ma (should be below 5) and will begin to heat up.    All those surrounding parts could not save it. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 01, 2016, 12:11:30 pm
Keysight meter is ran on the half cycle line simulator.   

https://www.youtube.com/watch?v=ju9JcAzgOeo (https://www.youtube.com/watch?v=ju9JcAzgOeo)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Muttley Snickers on February 01, 2016, 01:23:01 pm
Well that's a shame Joe, I really did like the look, form factor and feature set of these meters and if the other meter that is currently very popular wasn't out yet then I was looking to grab a few of the U1232A's whilst Keysight still had the bonus deal in place, I would imagine that a warranty claim is out of the question but you never know until you try.

Thank you for your fine efforts...... :-+


Muttley
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 02, 2016, 04:36:33 am
If the meters do what you want, I see no reason not to get them just because of the results from this test.   I was not at all surprised this Keysight meter was damaged beyond repair and was actually expecting it was going to fail at a much lower level.   Seeing that switch breakdown shows just how slow those things are to turn on.   It wouldn't have taken much to harden that design but seems that is always the story.   

I have yet to try to get any of the meters that have failed repaired under warranty.  Imagine the poor service tech.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on February 02, 2016, 11:45:50 am
If the meters do what you want, I see no reason not to get them just because of the results from this test.

Yep.

eg. The UT61E has a very capable 22000 count chipset and plenty of features. It's a very good meter for the price from a capability point of view. It even does data logging via serial cable.

It failed Joe's first test but there's no reason not to get one if you're a hobbyist who mostly works with low voltage DC stuff.

PS: You can get a UT61E and a super-robust Fluke 101 for less than $100. Two meters is always better than one and that's a very capable combination. It covers just about everything you'll ever need a multimeter for. If I was just starting out and had $100 to spend I could do a lot worse than buy those two.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 03, 2016, 02:48:11 am
It's too dry here to own a 61D or E.   Would hate to have a meter fail because I walked across the carpet without my wrist strap on and touch the leads.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 04, 2016, 04:35:55 am
I picked up a UNI-T UT210E clamp meter.   I had read some of the reviews on this site for it and a friend on mine was looking for a clamp so I thought we could check it out.   A few of us played with it today (just for the AC/DC current) and it's actually not a bad little clamp for the price.  More accurate than I was expecting.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on February 04, 2016, 08:32:05 am
It's too dry here to own a 61D or E.   Would hate to have a meter fail because I walked across the carpet without my wrist strap on and touch the leads.

In that case you leave the 61E on your bench (which must be grounded or you wouldn't be able to do anything) and you only carry the Fluke 101 around the house. :-)

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 04, 2016, 11:55:11 am
It's too dry here to own a 61D or E.   Would hate to have a meter fail because I walked across the carpet without my wrist strap on and touch the leads.

In that case you leave the 61E on your bench (which must be grounded or you wouldn't be able to do anything) and you only carry the Fluke 101 around the house. :-)

I will be the first to admit at home I rarely practice proper ESD handling.  I actually only have a couple of square feet of grounded mat on my bench where I solder and it's rare I use a strap.  As bad as it sounds, I would guess many hobbyist do not use anything for ESD.       
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 07, 2016, 02:29:46 am
Looking at the current inputs on a couple of meters. 

https://www.youtube.com/watch?v=_x9yV2ah4fg&feature=youtu.be (https://www.youtube.com/watch?v=_x9yV2ah4fg&feature=youtu.be)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 08, 2016, 12:32:54 am
It turns out there was not a second spark gap as I stated in the video.  Well, there was but I doubt it was an intended one.   The trace that routed to the current input was gone to about half way up the board.   I suspect this is when the control IC lost it's lid. 

In gap2, you can see how the arc jumped all the way to the common pads and started to erode them.   This is a fairly wide gap compared to what I am suspecting is an actual spark gap in gap1.   







Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 08, 2016, 12:42:13 am
Just because a meter uses a large fuse in the current does not mean that the layout is any better.   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: crispy_tofu on February 08, 2016, 01:10:52 am
The images don't seem to work...  :-[
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 08, 2016, 02:16:21 am
The images don't seem to work...  :-[

For some reason, when I pull from the camera directly it does not always copy. :-//    Fixed.

Here is the Fluke 17B+.   Note that they use an inner plane. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 08, 2016, 03:42:33 am
From another one of Danaher's divisions, 5ky's AM530.   Nice slit for the mA range and again, a fair amount of clearance. 
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 10, 2016, 12:18:04 pm
I was looking at Dave's video with Doug Ford where they put the Fluke 28II on Doug's generator.   At the start of the video Doug states:  4.2-4.3KV, <1ms discharge and 400J for the small generator.    I suspect this would be a fair bit different as he talks about charging the cap.    It appears they ran it with the selector in DC mode.   

My setup only puts at most in the 20J range at under 6KV.  Even when I test with the old generator at higher voltages, the generator is below 20J.  The pulse on the low voltage generator can be as wide as 100us FWHH and up to 50us on the high voltage generator.    This is why I never see the level of damage shown in Dave and Doug's video.   

Dave talks about the meter failing safe and is what he would expect.   I would assume the resistor shown lifted was in place or the MOVs would not have cut loose.    Based on how poorly the 87Vs I looked at performed, it makes sense to me that the 28II would see a fair amount of damage.   It would have been interesting to see the Fluke 101, 107, 17B+ and 115 on this same generator and then compare the results with the 28II.   

https://www.youtube.com/watch?feature=player_detailpage&v=M-FZP1U2dkM#t=653 (https://www.youtube.com/watch?feature=player_detailpage&v=M-FZP1U2dkM#t=653)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 11, 2016, 01:09:44 am
Two new meters are on order.   Maybe in a week or so I'll have something to show....
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on February 11, 2016, 08:34:57 am
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=199811;image)

 :palm:

What meter is that?

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: Fungus on February 11, 2016, 08:38:06 am
Two new meters are on order.   Maybe in a week or so I'll have something to show....

A blue one...?  :popcorn:
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 11, 2016, 11:30:05 pm
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=199811;image)

 :palm:

What meter is that?

It was 5ky's dt-9962T (rebranded Southwire)
https://www.youtube.com/watch?v=ZbZQx0SD7-Y (https://www.youtube.com/watch?v=ZbZQx0SD7-Y)
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 11, 2016, 11:39:07 pm
Two new meters are on order.   Maybe in a week or so I'll have something to show....

A blue one...?  :popcorn:

I would like to get one of his new meters when it becomes to see how it fairs with the others I have tested.   Maybe we will finally see one that holds it's own with the Flukes.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 16, 2016, 02:00:11 am
The first of the two meters made it in today. 

The attached picture shows the old and new test leads I plan to start using.   The new generator is fairly low risk to use.  Once it is down with the five transients, it turns off the HV supply.  Still, it's possible to touch the exposed ends of the banana connectors and have the generator fire.   The new ends are made by Multi-Contact.   I also made up a new set of leads for the scope probe, so there is now no exposed contact area.   

The new leads are the same length and gauge so it should not make a difference when testing.  I'll keep the original leads for meters that do not support the new ends or when using the alligator clips.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 17, 2016, 01:55:37 am
Second meter arrived today.   One is blue.   

I picked up the UNI-T UT210E a few weeks back and took it to work where it was passed around and abused for a few days.   I don't think anyone had a bad word to say about it.   No one used anything other than the current clamp.   This is the first UNI-T product I decided to keep, for now anyway.    My plan is to see what sort of BW it really has then maybe modify it.   

Hope to start testing again soon.   
Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 23, 2016, 03:42:19 am
A few people has asked me about running the Vici VC99 meter.   At first glance, I saw it was only rated for CAT II 1000 and did not plan to run it.   However it seems like a fairly popular meter for some reason.   Looking at the packing, they mention Fluke.   My guess is the printing would have been "Compared".   Maybe suggesting this is some how like a Fluke?  They have the color very close but that transistor socket would need to go. 

Looking at page 1 of the manual, its a 3 7/6 digit meter.  Or 4 1/6.   

The last statement on page 1 states "Please don't modify the circuitry arbitrarily, it may cause safety problem."   It's a good point.

My plan for this meter will be to review it like the last few I have looked at, then run it with the 2 ohm source rather than the 12 ohms called for by CAT II.   
   

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 28, 2016, 12:48:08 am
I wanted to make a couple of enhancements to my test jig before running these next meters.  During the shakedown run, I appear to have created a new rocket engine by accident.

Title: Re: Hear kitty kitty kitty, nope not that kind of cat. CAT III handheld surge tests.
Post by: joeqsmith on February 29, 2016, 06:30:44 pm
The VICI VC99 takes on the Flukes

https://www.youtube.com/watch?v=Q23eArAsXmo (https://www.youtube.com/watch?v=Q23eArAsXmo)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 01, 2016, 12:04:14 am
Spreadsheet has been updated.   The blue meter is next.
:scared:

I'll get my  :popcorn: ready, it's all gone watching the Vichi fry.  >:D



BTW, Joe, the thread title change is great.  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 01, 2016, 03:44:32 am
Great review on the VC99, Joe! Waiting for the smurf meter... ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 02, 2016, 01:06:33 pm
Great review on the VC99, Joe! Waiting for the smurf meter... ;)

Thanks.   Hopefully making more of a review, showing more how the meters are built and looking at the current inputs will be helpful to a few people.   

Just to be clear, the smurf meter is not the EEVBLOG rebranded Brymen.   A few people have asked about running a Hioki.  I am interested in it because it uses gas discharge tubes as part of its input protection like the Keysight meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 02, 2016, 10:07:44 pm
Great review on the VC99, Joe! Waiting for the smurf meter... ;)

Thanks.   Hopefully making more of a review, showing more how the meters are built and looking at the current inputs will be helpful to a few people.   

Just to be clear, the smurf meter is not the EEVBLOG rebranded Brymen.   A few people have asked about running a Hioki.  I am interested in it because it uses gas discharge tubes as part of its input protection like the Keysight meter.
Either the Hioki, the Davymen or a Itinlu (http://www.amazon.com/dp/B018IJBQPM/ref=sxr_pa_click_within_right_aps_sr_pg1_1?psc=1) DMM should be an interesting review.

BTW, I really loved your experiments with GDTs: I always had the impression nothing else in the world was better than GDTs for protection and the only reason they weren't used more was simply cost.

This idea was etched in my brain due to the massive GDT panels in telco distribution boxes, which probably made sense to protect kilometers of cables and their comparatively large reactance - a very different scenario inside a tiny and sensitive equipment such as a DMM.

Hopefully the Hioki fares better than the Agilent. Looking forward for this one.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 02, 2016, 11:54:07 pm
I saw where Martin?? did a review and talked about running a test like this using various parts.  Apparently he never got around to it or decided it was beyond his skill/comfort level.  It would have been interesting to see EEVBLOG put out a video like this as part of how the meter protection works.   Both of these guys could do a much better job than I have.    It's just hard to draw any conclusion from these tests.  My only goal was to show the difference in clamping speeds.   

The GDTs have their place for sure.   I think they would work very well in a meter if designed correctly but looking at how the Keysight  had no other clamp, I knew it was not going to fair well.   

Davymen?  Never heard of it.  Looked that the Itinlu, it's CAT II like the VICI and unfused.  Send a link for the other one and I will have a look at it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: blacksheeplogic on March 03, 2016, 12:34:05 am
The GDTs have their place for sure.   I think they would work very well in a meter if designed correctly but looking at how the Keysight  had no other clamp, I knew it was not going to fair well.   

I don't think you can really say it was not designed correctly. The design meets the relevant safety requirements as intended, failed in a safe manner and although non-functional it presented no safety risk in that failed condition.

As a user of that meter, we may prefer that it continued to operate but we really don't know what the designers thought process on this was. It may be that they felt a meter which sustained this kind of an event should be withdrawn or serviced/checked before being put back into the field in which case remaining functional after the event was not important to them.

Also, if the meter was sent back after it failed in the field due to this kind of non-dellibrate event it would very probably be replace under warranty without a great deal of fuss.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2016, 01:10:53 am
I don't think you can really say it was not designed correctly.

You may not think so but I stand by what I wrote. 

I have no idea if any of the meters I have looked at would fail in a safe manner or not if tested to the IEC standards.  These tests are about the electrical robustness of the meters.  If you want to know if a meter is safe or not, have it tested by an accredited lab.   

Do you feel the GDTs, MOVs, PTCs and secondary clamps are all there for safety alone?   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 03, 2016, 02:03:56 am
I saw where Martin?? did a review and talked about running a test like this using various parts.  Apparently he never got around to it or decided it was beyond his skill/comfort level.  It would have been interesting to see EEVBLOG put out a video like this as part of how the meter protection works.   Both of these guys could do a much better job than I have.    It's just hard to draw any conclusion from these tests.  My only goal was to show the difference in clamping speeds.   
I too always wanted to do an evaluation with GDTs and equivalent protection devices (I did one on varistors). The main issues are the controlled high voltage generator and the companion probe - so yes, so far you are the best equipped of all of us.

Davymen?  Never heard of it.  Looked that the Itinlu, it's CAT II like the VICI and unfused.  Send a link for the other one and I will have a look at it.
Sorry, I thought I had edited the "Davymen" out as soon as I had realized it was an extremely lame attempt to brand Dave's Brymen. This should have never surfaced.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 03, 2016, 03:09:57 am
@joeqsmith

are you going to test the Digitek DT-2843R too? or you already did it?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2016, 03:16:46 am
I saw where Martin?? did a review and talked about running a test like this using various parts.  Apparently he never got around to it or decided it was beyond his skill/comfort level.  It would have been interesting to see EEVBLOG put out a video like this as part of how the meter protection works.   Both of these guys could do a much better job than I have.    It's just hard to draw any conclusion from these tests.  My only goal was to show the difference in clamping speeds.   
I too always wanted to do an evaluation with GDTs and equivalent protection devices (I did one on varistors). The main issues are the controlled high voltage generator and the companion probe - so yes, so far you are the best equipped of all of us.

The probe is IMO one of the more useful things I made during this little adventure.   I never use my old Tektronix probe anymore.   It would not take a lot to build a generator.   I think the biggest mistake I made was not using modern parts.  But it was fun to wire wrap one last board and attempt to cram all that code in 2K.  Most of these tests are run below 10J.  Not something you want to mess with, but really I have a fair amount of safety built in to the system.   For example, covered leads now so there is nothing really exposed.  The generator turns off the power supplies once it is done and discharges them.  Of course I have my shorting stick.   And now the door that covers the meter if I am doing something stupid like looking at glass fuses.   I really only get concerned now when I play with that half cycle system.  When I use it, I arm it then walk away..   :-DD 


Davymen?  Never heard of it.  Looked that the Itinlu, it's CAT II like the VICI and unfused.  Send a link for the other one and I will have a look at it.
Sorry, I thought I had edited the "Davymen" out as soon as I had realized it was an extremely lame attempt to brand Dave's Brymen. This should have never surfaced.

That completely went over me!  :-DD :-DD  I would like to get a couple of the meters he is involved in working out the specs for.  One to benchmark and one for my own.    Last I looked they were still making changes to the specs.   Looking forward to seeing what they come up with.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2016, 03:25:51 am
@joeqsmith

are you going to test the Digitek DT-2843R too?

You two just like seeing those glass fuses pop don't you?! :-DD   Looks like there is an 102KD14 MOV right across the input leads? Can anyone confirm this?
 

(https://www.eevblog.com/forum/testgear/digitek-dt-2843r-acdc-true-rms-multimeter-mini-review-and-teardown/?action=dlattach;attach=37357;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 03, 2016, 04:04:06 am
yes, there is a MOV, a picture of mine, sory for the bad quality
Title: Re: Handheld meter electrical robustness testing.
Post by: blacksheeplogic on March 03, 2016, 04:18:17 am
I don't think you can really say it was not designed correctly.

You may not think so but I stand by what I wrote. 

I have no idea if any of the meters I have looked at would fail in a safe manner or not if tested to the IEC standards.  These tests are about the electrical robustness of the meters.  If you want to know if a meter is safe or not, have it tested by an accredited lab.   

Do you feel the GDTs, MOVs, PTCs and secondary clamps are all there for safety alone?

It's OK and I understand you are only testing robustness, but that is irrelevant to the point made. You are using your robustness criteria and passing a judgment on their design as being incorrect. My point was that their design criteria was possibly different to yours and based on their design requirement requirements it was designed correctly.

You don't have to like it, or buy their meter because of it, and it's perfectly valid to complain or criticize the electrical robustness of the meter that did not meet your expectations. But it's not correct to say it was not designed correctly based on your design criteria.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2016, 10:08:06 am
I don't think you can really say it was not designed correctly. The design meets the relevant safety requirements as intended, failed in a safe manner and although non-functional it presented no safety risk in that failed condition.

It's OK and I understand you are only testing robustness, but that is irrelevant to the point made.

You come on here and want to post about safety on a meter that was tested at sub 20J.   Now you post you understand.   I doubt you have any clue what is going on in the videos which explains why you failed to answer my question.   

You are using your robustness criteria and passing a judgment on their design as being incorrect.
I have not edited my original post and stand by it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2016, 10:13:17 am
yes, there is a MOV, a picture of mine, sory for the bad quality

Thanks.   I have seen a placeholder for what appeared to be a MOV across the inputs on another meter.   I believe this is the first meter I have seen with a MOV on the front side of the PTCs. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2016, 01:12:44 pm
For all of you Hioki fans, thanks for being patient.   Watch as their DT4252 is put to the test.

https://www.youtube.com/watch?v=ZCQCmhr5AYQ (https://www.youtube.com/watch?v=ZCQCmhr5AYQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 08, 2016, 01:47:06 pm
Measure down to 10A...?  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2016, 11:28:07 pm
Measure down to 10A...?  :-//

Maybe down was correct and the "0" was supposed to be an "m"?   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2016, 06:33:04 pm
The Hioki DT4252 part 2.

https://www.youtube.com/watch?v=Acqktm1fgHo (https://www.youtube.com/watch?v=Acqktm1fgHo)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 10, 2016, 11:05:02 pm
tuff meter, huh?   :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2016, 11:22:44 pm
tuff meter, huh?   :-+

If it had just a small amount more plastic in that guard I would not be surprised if I could not damage it.   

I have updated the spreadsheet for those interested.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 10, 2016, 11:46:42 pm
tuff meter, huh?   :-+

If it had just a small amount more plastic in that guard I would not be surprised if I could not damage it.   

I have updated the spreadsheet for those interested.

hehe, I really would like to have one of these...but heh "just dreams" nevermind

and thanks for the nice testing videos  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: quarks on March 11, 2016, 01:46:47 am
Great work and very informative :-+ :-+ :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on March 13, 2016, 04:59:21 pm
Great work, Joe, as always on this entire series.

Hioki builds great devices, but this Hioki DMM series continues to have 2 shortcomings. 

First, the creepage distances are a bit close [ as Joe points out too] in other areas.

https://www.eevblog.com/forum/testgear/new-hioki-multimeer-and-first-project/msg736814/#msg736814 (https://www.eevblog.com/forum/testgear/new-hioki-multimeer-and-first-project/msg736814/#msg736814)

Why is there no NRTL safety rating beyond CE or KCC [ the are not recognized in the USA by OSHA ]?  It may be because of what Joe shows.

From the slow motion, where the creepages are too close, added areas of arcing occur. If all the arcing is stopped by the plastic spacer it would be best to reshoot the video showing no added arcing occurs. 

The basic Hioki design out of box however, has a fault, and it allows arcs to propagate despite the GDT input protection at the 8kV impulse, which is the CAT III, 600V rating.

You can see the GDT glowing in the videos.  the GDT is simply not fast enough for this application.

http://blog.circuitprotection.com/communications/movs-vs-gdts-which-one-do-i-use/ (http://blog.circuitprotection.com/communications/movs-vs-gdts-which-one-do-i-use/)

It would be better to use both the MOV and GDT at the inputs or MOV alone.  The GDT acts to prolong the life of the MOVs particularly in high energy overvoltage.

Recall, this is a test impulse.  The real world worse case is that the impulse rides atop high energy AC, such as line voltage, and if the arcing occurs, it provides the pathway for an arc blast.

In this screen grab, one arc extended around the plastic shield from V+ terminal.  Another extends from the center GND terminal from one of end of the fuse and from the fuse end to the ground plane.  You can also see the GDT glowing.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=208195;image)

In this grab, the corona post arcing lights up the fault areas.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=208197;image)

The meter surviving the arc is a good thing, but that could be because so much energy is shunted across the inputs nothing appears to the more high impedance DMM circuitry.

However, the point of the protective devices is to protect the user first, not the DMM, for the specific CAT rating of the meter.




The Hioki DT4252 part 2.

https://www.youtube.com/watch?v=Acqktm1fgHo (https://www.youtube.com/watch?v=Acqktm1fgHo)
Title: Re: Handheld meter electrical robustness testing.
Post by: mos6502 on March 13, 2016, 07:11:19 pm
However, the point of the protective devices is to protect the user first, not the DMM, for the specific CAT rating of the meter.

Well, that's a bit of a flaw in this entire test series. It's like doing crash tests with cars, and then concluding that the car that deformed the least must be the best one, without considering what would have happened to the occupants.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 14, 2016, 12:57:42 am

From the slow motion, where the creepages are too close, added areas of arcing occur. If all the arcing is stopped by the plastic spacer it would be best to reshoot the video showing no added arcing occurs. 

It would be better to use both the MOV and GDT at the inputs or MOV alone.  The GDT acts to prolong the life of the MOVs particularly in high energy overvoltage.

Recall, this is a test impulse.  The real world worse case is that the impulse rides atop high energy AC, such as line voltage, and if the arcing occurs, it provides the pathway for an arc blast.

In this screen grab, one arc extended around the plastic shield from V+ terminal.  Another extends from the center GND terminal from one of end of the fuse and from the fuse end to the ground plane.  You can also see the GDT glowing.

The meter surviving the arc is a good thing, but that could be because so much energy is shunted across the inputs nothing appears to the more high impedance DMM circuitry.


If you like, I can re-shoot the video with the 14KV pulse and the small insert.   

What I mention in the video as being a possible secondary clamp are marked BZ 4CZRV  and BZ 5DGS9.   

You are very much correct, both of these generators are very low energy (less than 20J).  The original generator will output a 50uS FWHH with an open but will not meet the IEC current waveform.  For reason!! 


However, the point of the protective devices is to protect the user first, not the DMM, for the specific CAT rating of the meter.

Well, that's a bit of a flaw in this entire test series. It's like doing crash tests with cars, and then concluding that the car that deformed the least must be the best one, without considering what would have happened to the occupants.

Car crash testing infers safety, which again is not what these tests have ever been about.   Of course the internet is filled with people who will never figure this out. 


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 14, 2016, 01:29:18 am
Guessing it is a BZ series TVS from Littlefuse.  Very fast...

You pointed out how it arcs without the fuse on the right.  If I rerun the meter, would you like the fuse in place (which should prevent that arc)?     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 15, 2016, 02:58:36 am
Guessing it is a BZ series TVS from Littlefuse.  Very fast...

You pointed out how it arcs without the fuse on the right.  If I rerun the meter, would you like the fuse in place (which should prevent that arc)?   

I looked up the parts I suspected were TVSs.  Looks like the BZ is the part and the rest is the date code.  The BZ is a SMAJ24A or SMBJ24A,  400W unidirectional TVS.  Switching time will be very fast on these.  Once the GDT fires, it should dissipate most of the energy.   



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 15, 2016, 03:04:53 am
I took a few pictures of the second breakdown that was pointed out.   In this first picture, the red line shows the path, starting with the input, across the slit (note the plastic insert from testing), to the fuse holder.  Because there was no fuse installed, it was going to go between the common and Amp connectors or instead it jumped to the right side of the fuse holder and followed its way back to the common.
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 15, 2016, 03:27:14 am
In these two pictures we can see where the arc took place.  The blue is where I touched it with the ink pen during the video.   Again, had the fuse been in place, it would have just jumped at the one side (with this generator).   

What makes it unique is normally once a meter arcs, they will fail functionally as I increase the levels. In most cases the meters are not repairable.   I would guess in many cases there is some form of arc that happens before the meters become nonfunctional.  I may not always hear it or see it on the DSO.   

Some meters like the Flukes, Brymen, AMPROBEs, there has been enough additional protection circuitry that it has saved the control IC and I have been able to repair them to some degree (less PCB damage).     In the case of the Hioki, we have a meter that requires about 10KV to arc across a controlled gap and no damage to any of the electronics.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 15, 2016, 04:03:22 am
Closer view of area
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 16, 2016, 02:00:51 am
However, the point of the protective devices is to protect the user first, not the DMM, for the specific CAT rating of the meter.

I would guess that most of the safety in hand held meters comes from the mechanics.   Things like spacing, wall thickness, double walled, etc.  Things like the GDTs, MOVs, secondary clamps, PTCs are there to protect the meter so it does not need to be replaced or repaired.   Maybe have a look at patents 5396168, 5606481, 5920188
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 20, 2016, 02:32:53 am


https://www.youtube.com/watch?v=a2NVLzWV3_Q (https://www.youtube.com/watch?v=a2NVLzWV3_Q)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 20, 2016, 03:08:05 am
nice meter  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 21, 2016, 02:19:47 am
nice meter  :-+

I don't like how the Hioki has an error when there is a large offset in an AC signal.  Not a fan of the display or back light on it.   

I was looking at the Digitek DT-2843R you asked about.  5ky had sent me a TekPower TP2844R.   The circuit boards for the two meters are very similar.  There is a placeholder for the MOV on the TekPower but it was not populated.   The Digitek PCB is marked K10062843R,  the TekPower is K10052844R.   It may do better with the MOV installed across the inputs with my tests but it seems like a bad idea.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 21, 2016, 02:54:10 am
nice meter  :-+

I don't like how the Hioki has an error when there is a large offset in an AC signal.  Not a fan of the display or back light on it.   

I was looking at the Digitek DT-2843R you asked about.  5ky had sent me a TekPower TP2844R.   The circuit boards for the two meters are very similar.  There is a placeholder for the MOV on the TekPower but it was not populated.   The Digitek PCB is marked K10062843R,  the TekPower is K10052844R.   It may do better with the MOV installed across the inputs with my tests but it seems like a bad idea.

thank you for taking a look into it, I saw your video testing it, and from that other guy too, I just wanted to know more clearly how it would do with some harder testing, and yeah better be careful.
and about the hioki, I liked it, it's a very robust meter, that can handle some bad stuff very well, I would buy one without doubt if I could, did a search just for curiosity, but they don't sell them here in brazil, I found a rebranded brymen, but the price is ridiculous, I think it's the same model that Dave is selling, maybe in the future I get something better if I can.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 22, 2016, 02:25:04 am
nice meter  :-+

I don't like how the Hioki has an error when there is a large offset in an AC signal.  Not a fan of the display or back light on it.   

I was looking at the Digitek DT-2843R you asked about.  5ky had sent me a TekPower TP2844R.   The circuit boards for the two meters are very similar.  There is a placeholder for the MOV on the TekPower but it was not populated.   The Digitek PCB is marked K10062843R,  the TekPower is K10052844R.   It may do better with the MOV installed across the inputs with my tests but it seems like a bad idea.

thank you for taking a look into it, I saw your video testing it, and from that other guy too, I just wanted to know more clearly how it would do with some harder testing, and yeah better be careful.
and about the hioki, I liked it, it's a very robust meter, that can handle some bad stuff very well, I would buy one without doubt if I could, did a search just for curiosity, but they don't sell them here in brazil, I found a rebranded brymen, but the price is ridiculous, I think it's the same model that Dave is selling, maybe in the future I get something better if I can.

This would be the one time it would be fun to run it with the included probes on a real generator rather than my toy setup.  It would not tell you anything about how it compares with the other meters but we could get a pretty good idea about safety.  If I remember, next order I'll see if Digikey stocks the MOVs and get a few.  Maybe just hook one across my toy generator and get some good high speed footage from it.   

I had seen a video where someone was showing a bunch of pocket meters.   They did not take them apart or try to stress them.  I may pick up a few low end ones and see how they look. 
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 22, 2016, 03:39:23 am
if you get some pocket meters, let us see how they are, I'm curious too
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 22, 2016, 01:08:34 pm
Not a problem.  I ordered a few of them.  Maybe in a couple of weeks I'll have some time to start checking them.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 26, 2016, 02:30:11 am
Attempt to test an MOV directly connected to my generator.   

https://www.youtube.com/watch?v=f99Ra1O_u7s (https://www.youtube.com/watch?v=f99Ra1O_u7s)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 26, 2016, 02:54:10 am
 you are the one who likes the firecrackers  :-DD , I'm curious how the pocket meters will do, or how many will just pop, and thanks for taking the time to test with the MOV  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 26, 2016, 03:17:23 am
you are the one who likes the firecrackers  :-DD , I'm curious how the pocket meters will do, or how many will just pop, and thanks for taking the time to test with the MOV  :-+

 :-DD I just could not leave the video ending with not being able to run the test.  Dave had made a recent video showing his new high speed camera.  He had attempted to blow a few caps without success.   I figured, may as well show the same thing.  Then I forgot to arm the camera on the first cap.   |O  These cameras are pretty good for the price but they are just not fast enough.   

I had actually ordered a few MOVs that are very close to what is used in the Digitek.  This was before I attempted to test the smaller part.  Sorry it did not work out but I am still thinking that putting all of this current through the leads and meter is not good.

Looking at the UT20, it is marked CAT II 300V.  Without even seeing the other ones I ordered, I can pretty much guess that none of them will hold to the levels 5ky's Fluke 107 did.  :-DD     

I plan to spend some time looking at that UT210E first.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2016, 05:20:08 am
What's bigger than the Brymen BM869s?  The UNI-T UT181a!   There is not a lot of information about this meter.  This site has a few reviews of it and there are some pictures showing the insides which is what perked my interest in seeing one first hand.  So many PTC, MOVs, diode clamps.   :scared:  The two 139s I looked at were damaged around 5KV.   By far one of the more robust UNI-T handheld meters I looked at.  When I received the UT210E and pulled it apart, again it appears they are actually making an attempt add protection.   This is a major change from the UT61D & E which had no protection.  |O |O   

I started this thread with a bias against Fluke.  How that has changed....   When it came to UNI-T, my only bias was from watching videos, that is until I started testing them.  I went from no bias, to no clue, to their really bad, to their better than most, to WOW a mA DC/AC current probe that works for under $100!!    :-DD 

I am not a big fan of the battery pack, but I was not a fan of Brymen putting that 9V transistor battery in the 869s.  It comes with the serial interface which the 869s did not.  It also came with a couple of K-types where the 869s came with only one.   It even has a little carry case.   The Brymen is UL listed.  Then I look at this 181 and there is an Intertek mark on it?! 

So here you go, 1st picture both meters showing AC+DC.  I am liking that tri-display, plus a digit here and there.   Looks like my original battery in the Brymen is finally starting to fail.

2nd picture showing both meters with 1 Volt DC off the Fluke.   

As much as I am not a fan of UNI-T (well except for the 210E) the little I have played with this 181A, I have to admit, I like it.  It's just the honeymoon. Give me some time with it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2016, 05:45:05 am
I get feedback on some of my meter videos that talk about the testing not being real world and how meters would never see these sort of conditions.  Recently, I had an opportunity to pull apart a power supply that had been hit with a real line transient.  So to be clear, not to the IEC or any other standard.   I then wondered what would happen if I ran the same power supply on my home made generators.   
 
https://www.youtube.com/watch?v=Ls0ug-Y5FfQ (https://www.youtube.com/watch?v=Ls0ug-Y5FfQ)


Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 31, 2016, 06:19:40 am
yeah that gives a pretty good idea, what could happen without some good input protection, even if your generator isn't that powerfull, now I'm curious about the new meter, looks like you wont pop this one  :-DD  I like your videos too  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: Mark on March 31, 2016, 05:15:14 pm
I was about to start a thread about the UT-171B vs the Brymen 869S so I am glad I saw your posts on the UT-181A.  I had fallen in love with the 181's huge easy-to-read screen but when I found out about the 2 update/sec rate I was so disappointed.  Is the update rate really that bad for such a modern meter? 
The 171B seems to be around 5/sec which is why I started looking at that meter as an alternative, but the niggly feeling that there is no such thing as a "high end UNI-T" remains...
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 31, 2016, 10:29:58 pm
@ Joesmith

here is a teardown of my oldie, Motech MIC 2200 A, the pics aren't great quality, but I think you can have an idea, just tought you might be interested, ok? it probably wouldn't survive your tests lol

the only reference to the brand, but it's not the same meter, BKprecision got the multimeter part from Motech

http://www.radiomuseum.org/r/motech_digital_multimeter_mic_7s.html (http://www.radiomuseum.org/r/motech_digital_multimeter_mic_7s.html)

Intersil 7106
(https://www.intersil.com/content/dam/Intersil/documents/icl7/icl7106-07-07s.jpg)




Title: Re: Handheld meter electrical robustness testing.
Post by: crispy_tofu on March 31, 2016, 10:38:02 pm
I wonder if that's an ICL7106...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2016, 11:00:56 pm
@ Joesmith

here is a teardown of my oldie, Motech MIC 2200 A, the pics aren't great quality, but I think you can have an idea, just tought you might be interested, ok? it probably wouldn't survive your tests lol

the only reference to the brand, but it's not the same meter, BKprecision got the multimeter part from Motech

Thanks!  I like looking at old equipment and how it was built.  It's too bad that the LCD is cracked.     

I saw an old 80's digital hand held for sale local but they wanted about $40 for it with unknown condition.  Had the side slide switches. 


I was about to start a thread about the UT-171B vs the Brymen 869S so I am glad I saw your posts on the UT-181A.  I had fallen in love with the 181's huge easy-to-read screen but when I found out about the 2 update/sec rate I was so disappointed.  Is the update rate really that bad for such a modern meter? 
The 171B seems to be around 5/sec which is why I started looking at that meter as an alternative, but the niggly feeling that there is no such thing as a "high end UNI-T" remains...

 :-DD :-DD  First let me say I have that same feeling about UNI-T.    You are not alone!!  This will be the eighth product I looked at from them and I am trying to keep an open mind.   In all honesty, I keep thinking "Please, what ever you do, don't fail that stupid ESD test!!!"    :palm: :-DD   

There was a decent write up on this site about the 181A.   Have a look.     My plan was to basically follow the same review format I used to show the last six or so meters.   People seem to get more out of it rather than just stressing their inputs.   If you have something you would like to see with the 181, just let me know and I will see if I can set up a test for you. 

I may do that instead of playing with the 210E this weekend, so let me know.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on March 31, 2016, 11:11:27 pm
@ Joesmith

here is a teardown of my oldie, Motech MIC 2200 A, the pics aren't great quality, but I think you can have an idea, just tought you might be interested, ok? it probably wouldn't survive your tests lol

the only reference to the brand, but it's not the same meter, BKprecision got the multimeter part from Motech

Thanks!  I like looking at old equipment and how it was built.  It's too bad that the LCD is cracked.     

I saw an old 80's digital hand held for sale local but they wanted about $40 for it with unknown condition.  Had the side slide switches. 


it's not cracked, probably the seal failed, I tryed to seal it again with some vitral warnish, it's probably a manufacturing problem, never fell or anything like that, it works just fine, I don't have any precision reference, but I did compare it to the Digitek and it hasn't drifted to much, almost spot on
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on April 01, 2016, 12:02:30 am
That's great research, Joe.  The Fluke patent is particularly interesting because that is now widely used by others, the plastic shields to supplement the creepage and clearances.  As for the RS patents, in the early days of DMMs, input protection varied from maker to maker, but the prime focus was avoiding damage due to incorrect settings such as measuring voltages on ohms range.  There was not much talk about impulses.

Once the IEC model for impulses on line voltage was agreed on, by 1992? CAT ratings were created, with a goal of user safety.  I think only Fluke continues to state their meters survive the CAT rating impulse while the IEC criteria don't specify the device be functional after a successful test.

Today, I don't think any DMM can survive the required maximum impulse for its CAT rating without externally added impulse protective devices.  However, your video series shows some DMMs can be designed to not only pass the CAT rating but also survive the rated impulses.

IIRC, some of your videos also show cheaper meters failing short of their CAT rating, while better brand meters being more consistent. 


However, the point of the protective devices is to protect the user first, not the DMM, for the specific CAT rating of the meter.

I would guess that most of the safety in hand held meters comes from the mechanics.   Things like spacing, wall thickness, double walled, etc.  Things like the GDTs, MOVs, secondary clamps, PTCs are there to protect the meter so it does not need to be replaced or repaired.   Maybe have a look at patents 5396168, 5606481, 5920188

Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on April 01, 2016, 12:44:08 am
I think Joe is doing everyone a great service, not only does he have the skills to play with kV, he gives a superb post mortem, repairs the meter quickly [if possible?], then subject it to more impulses.  Plus, more kudos for buying these meters himself to avoid patron bias, like a one man Consumer Report.

I don't think anyone on the net has demonstrated just what an impulse would do and compare it against other DMMs, than this series. 

IIRC the highest test impulse is ~ 12kV for CAT IV 1000V.  Joe's videos show test as high as 14kV or 15kV?
These are close enough to represent a slightly higher than CAT IV requirement for real world testing.

If the meter survives 15kV then all is well.  If not, one could bicker strictly speaking that its higher than the IEC requires.

In Fluke promo video, they show the 87V failing at 17kV, but making it past 15kV [ but they do not show a full functional test between and the test is only done on the V scale.]


https://www.youtube.com/watch?v=IzwN8yibjjA (https://www.youtube.com/watch?v=IzwN8yibjjA)


Begins at 16:00


I get feedback on some of my meter videos that talk about the testing not being real world and how meters would never see these sort of conditions.  Recently, I had an opportunity to pull apart a power supply that had been hit with a real line transient.  So to be clear, not to the IEC or any other standard.   I then wondered what would happen if I ran the same power supply on my home made generators.   
 

Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on April 01, 2016, 12:53:35 am
Joe I think you clearly show how to remediate this meter to make it a true CAT III, and thanks for ID the other protective devices.  The Hioki is built very well, I just can't figure why they didn't go just a tiny bit more to give it the kind of impulse hardening you show can be done, fairly cheaply and easily too. 




https://www.youtube.com/watch?v=a2NVLzWV3_Q (https://www.youtube.com/watch?v=a2NVLzWV3_Q)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 01, 2016, 01:00:20 am
I don't think anyone on the net has demonstrated just what an impulse would do and compare it against other DMMs, than this series. 

Nope.

I get feedback on some of my meter videos that talk about the testing not being real world and how meters would never see these sort of conditions.  Recently, I had an opportunity to pull apart a power supply that had been hit with a real line transient.

The office where my missus works recently had some sort of power surge. It left their telephone switching board looking a bit like the PCB in your video.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 01, 2016, 01:12:44 am
it's not cracked, probably the seal failed, I tryed to seal it again with some vitral warnish, it's probably a manufacturing problem, never fell or anything like that, it works just fine, I don't have any precision reference, but I did compare it to the Digitek and it hasn't drifted to much, almost spot on

That's too bad.   I have the second calculator I ever bought and it is slowly turning black as well. Maybe you could find a replacement LCD for it if you wanted to keep the meter.     

For home, I used to have a bunch of loose parts that I would use to check my meters.   I finally stuck them all in a box along with a non temperature controlled reference and a few other parts to aid in meter check out.  This has really helped me speed up my testing during these transient tests.

 
That's great research, Joe.  The Fluke patent is particularly interesting because that is now widely used by others, the plastic shields to supplement the creepage and clearances.  As for the RS patents, in the early days of DMMs, input protection varied from maker to maker, but the prime focus was avoiding damage due to incorrect settings such as measuring voltages on ohms range.  There was not much talk about impulses.

Once the IEC model for impulses on line voltage was agreed on, by 1992? CAT ratings were created, with a goal of user safety.  I think only Fluke continues to state their meters survive the CAT rating impulse while the IEC criteria don't specify the device be functional after a successful test.

Today, I don't think any DMM can survive the required maximum impulse for its CAT rating without externally added impulse protective devices.  However, your video series shows some DMMs can be designed to not only pass the CAT rating but also survive the rated impulses.

IIRC, some of your videos also show cheaper meters failing short of their CAT rating, while better brand meters being more consistent. 

I have a friend who worked for a company that made meters in the 70s.   He did a lot of repair work for them.  He was telling me about some of the meters that would get returned for repairs and some of the damage they had.    :phew:  It makes sense back then that the main goal would be making the product survive.   

The testing the member had done after the first round of meters was done using a real generator.  This at least backed up what I found during my testing with the Fluke 101.   I try to be clear about what exactly I am doing when I run these test but was really happy to see someone attempt to repeat my results.   :-+   Because this test, IMO shows exactly what you stated.  A meter can be designed to not only pass but survive and in some cases survive far beyond what they are rated for!   

I had mentioned early on that I had spoke with a few companies about the IEC testing and how they interpreted the requirements.   In a nut shell,  Fluke was the one company that told me that they design the meters to survive the tests.   How the 87V fits into this I am not sure.   Too old a meter any they changed their goals perhaps.  It was a big surprise for me to see how poorly it performed.   Brymen was very upfront with me when I started to test the 869s.  That meter survived higher than they thought it would.   If I had a virgin one, I would repeat the tests to get a better idea what levels it can take.  Hioki was not too big of a surprise for me.  I have used their gear.  They know the environment and their products need to survive in it.   The Keysight was a disappointment but I was not too surprised after watching Dave's review.  His camera did a very good showing how that meter was built.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 01, 2016, 01:32:45 am
I think Joe is doing everyone a great service, not only does he have the skills to play with kV, he gives a superb post mortem, repairs the meter quickly [if possible?], then subject it to more impulses.  Plus, more kudos for buying these meters himself to avoid patron bias, like a one man Consumer Report.

I don't think anyone on the net has demonstrated just what an impulse would do and compare it against other DMMs, than this series. 

...

In Fluke promo video, they show the 87V failing at 17kV, but making it past 15kV [ but they do not show a full functional test between and the test is only done on the V scale.]

Thanks and glad your enjoying them.   We can't forget about 5KY's contributions as well!  Big thanks for giving me the opportunity to see just how much a Fluke 107 can take!! :-DD   

When I run that half cycle generator, the meters are placed in their VAC mode as well.  This seems to be the right thing to do for a test like this.     I can believe that the 87V without doing any sort of functional testing  and only using the VAC mode would not have a problem at higher voltages than the last one I looked at.   But, then what would be the point of the  test??  :-DD   


Joe I think you clearly show how to remediate this meter to make it a true CAT III, and thanks for ID the other protective devices.  The Hioki is built very well, I just can't figure why they didn't go just a tiny bit more to give it the kind of impulse hardening you show can be done, fairly cheaply and easily too. 


 I'll tell you why.  They are trying to save me from having to build another generator!!  :-DD   Really, I have no idea.   Maybe it would make it unsafe some how?   That's actually a pretty nice little meter.   

The office where my missus works recently had some sort of power surge. It left their telephone switching board looking a bit like the PCB in your video.

Hope no one was hurt.   I think most people involved with electrical and electronics are aware that events like this can/do happen.   
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 01, 2016, 02:16:04 am
yes I intend to keep the oldie( it was a gift from somebody very close), but here in brazil it's probably impossible to find a replacement for this LCD, now they started to sell rebranded Brymens here, but they prices are ridiculous, I probably could get a fluke cheaper,but now I can't afford jack...I hope in the near future I'll get at least one real good meter, but...
I'll take a look at my stuff, to see if I can put something togheter

and your videos really do a good service, they are a good reference for people, and thanks to that guy who donated the meters for to testing, a real nice gesture
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 02, 2016, 02:47:00 am
yes I intend to keep the oldie( it was a gift from somebody very close), but here in brazil it's probably impossible to find a replacement for this LCD, now they started to sell rebranded Brymens here, but they prices are ridiculous, I probably could get a fluke cheaper,but now I can't afford jack...I hope in the near future I'll get at least one real good meter, but...
I'll take a look at my stuff, to see if I can put something togheter

and your videos really do a good service, they are a good reference for people, and thanks to that guy who donated the meters for to testing, a real nice gesture

Wow, the Flukes are less expensive than Brymen!  That's a twist! 

It was a real nice gesture when 5ky (TechnologyCatalyst on youtube)  agreed to donate those meters.   I doubt very much I would have continued to test meters had it not been for that.   It also forced me to come up with a better way to test them and to start publishing the results.   It was a big win for the few people who are following along.   

Weekend is here and I have a UNI-T calling my name.....
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 02, 2016, 04:57:30 am
yes I intend to keep the oldie( it was a gift from somebody very close), but here in brazil it's probably impossible to find a replacement for this LCD, now they started to sell rebranded Brymens here, but they prices are ridiculous, I probably could get a fluke cheaper,but now I can't afford jack...I hope in the near future I'll get at least one real good meter, but...
I'll take a look at my stuff, to see if I can put something togheter

and your videos really do a good service, they are a good reference for people, and thanks to that guy who donated the meters for to testing, a real nice gesture

Wow, the Flukes are less expensive than Brymen!  That's a twist! 

It was a real nice gesture when 5ky (TechnologyCatalyst on youtube)  agreed to donate those meters.   I doubt very much I would have continued to test meters had it not been for that.   It also forced me to come up with a better way to test them and to start publishing the results.   It was a big win for the few people who are following along.   

Weekend is here and I have a UNI-T calling my name.....

kinda strange really, the Brymens are rebranded by Minipa, they sell cheaper meters, they have a big "line" of rebranded chinese meters, that I really doubt that they match the CAT ratings printed on them, some are  unfused  :palm: , there are other brands, but I wouldn't say they are safe, but man, you got me going on that Hioki, now I want one  :-DD

now maybe they are few, but like TheRadioTech started with few people and now has almost 1000 subscribers, continue and more and more people will start to follow  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on April 02, 2016, 03:58:29 pm
Yes, mea culpa thanks to TC for providing the meters!

Your generator remains impressive, early in this thread Meter Junkie shows the Fluke 101 using an industrial quality one which is in $5k range, to start, I think the video shows a MegaPulse by Compliance West. 

https://www.youtube.com/watch?v=4hk5Vmf65-4 (https://www.youtube.com/watch?v=4hk5Vmf65-4)

For the rest of us, one can do limited tests using much easier to access and afford kV sources like a hipot tester or an electrophoretic supply.

Given your generator, setup, and interest, keep on testing! 

An idea, you could show how good older branded meters are, or not, on their impulse resistance.  There are many pre-CAT and older CAT rated meters sold on Ebay. 

Fluke 23, 25, 77, 8021, first generator 80s series, HP and Tektronix DMMs, Craftsman, Micronta, Beckman Industrial etc., as well as Japanese meters from the golden era such as Hioki, Sanwa, Yokogawa [ that were made in Japan.]

Also you can extend your tests to dielectric withstand of the chassis to the PCB, particularly in older meters, which could have deteriorated over time.



Thanks and glad your enjoying them.   We can't forget about 5KY's contributions as well!  Big thanks for giving me the opportunity to see just how much a Fluke 107 can take!! :-DD   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 02, 2016, 04:28:58 pm
Imagine having a generator like that at home!  My concern would not be so much from dieing of electrocution but from my wife.   

I had thought about using a Hi-pot tester early on when I was trying to think of how to benchmark them.   My concern was that it would not represent an actual transient condition and with it being such a low energy, it may not allow me to sort them out.  It would be interesting to see someone running some different tests in parallel but there is a fair amount of cost and time involved.    There is a guy on youtube that has done a lot of meter reviews and he talked about running some test like this but in the end never did any more with it.   

I would be all for testing a few older meters for fun but sourcing them is a problem.  I have not had an eBay account in maybe 10 years.  People will comment how they trust their old ..... meter on mains.  Fluke will tell you otherwise in many cases.   

Well, break time is over.   Shooting video today so again, if anyone wants to see something specific with the 181A, now is the time to ask.  Meters don't typically live very long in my hands.
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 03, 2016, 02:44:27 am
The original review showing the internals of the 181A:

https://www.eevblog.com/forum/testgear/uni-t-ut181a-pictures/ (https://www.eevblog.com/forum/testgear/uni-t-ut181a-pictures/)

Spent the day using the meter.  The update rate does appear to be 2Hz regardless of the range.  I would have thought with the lowest resolution range, the update rate would increase but it appears to remain fixed.  A little strange is that the bar graph is actually updated at a fairly good rate.   That said, for me personally the 2Hz is not that big of a deal but I did send UNI-T an email about it.     

Hope to have the first part upload it in the next day or so.         
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 03, 2016, 09:35:47 pm
The UNI-T UT181A gets no special treatment....   Video is long, so grab some popcorn before you load it up.

https://www.youtube.com/watch?v=PjNXbKlr3MI (https://www.youtube.com/watch?v=PjNXbKlr3MI)
Title: Re: Handheld meter electrical robustness testing.
Post by: Maxlor on April 03, 2016, 10:37:29 pm
Heh, the end of that is rather anticlimatic. It'd be really disappointing if that's all it takes to kill that meter. I'm hoping and guessing that it's the soft power feature that's causing the issue there (why do manufacturers feel they have to add soft power on high end meters?)

Btw, one thing you mention in nearly every video is the term FWHH, but I don't understand what that means. Maybe you explained it already somewhere, but I missed it? If not, maybe you could show a scope trace of what it means exactly if you find the time.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 03, 2016, 11:21:47 pm
 :wtf: dead with one hit??? yeah that old saying is always right, when it looks too good... I'm really disapointed, I tought it would perform better tha that, but the video was excelent
Title: Re: Handheld meter electrical robustness testing.
Post by: smithnerd on April 03, 2016, 11:57:36 pm
The old Uni-T Achilles heel.  :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 05, 2016, 01:51:25 am
Heh, the end of that is rather anticlimatic. It'd be really disappointing if that's all it takes to kill that meter. I'm hoping and guessing that it's the soft power feature that's causing the issue there (why do manufacturers feel they have to add soft power on high end meters?)

After the video, I pulled both batteries and reinstalled.  It's dead. Disappointing yes but typical for that brand. 

Btw, one thing you mention in nearly every video is the term FWHH, but I don't understand what that means. Maybe you explained it already somewhere, but I missed it? If not, maybe you could show a scope trace of what it means exactly if you find the time.

If you look up full width half maximum you would find it.  The width of the pulse at half the height.    So if I use a 1KV pulse, that is 1KV peak, and at 500V if you measured the width, you would have in my case, 100us in most cases.   If I call out a 2 ohm source, that's the impedance from the generator to the meter. 

:wtf: dead with one hit??? yeah that old saying is always right, when it looks too good... I'm really disapointed, I tought it would perform better tha that, but the video was excelent

Yes, just that one hit damaged it.   But data is data and there is no reason to try and sugar coat it.  Glad you enjoyed the video. 

The old Uni-T Achilles heel.  :palm:
Three of the five that failed this were UNI-T.  This was a test I really thought was a waste of my time to even run as that starter is not much of a pulse.   

I was asked about the pulse it put out.  This is a little difficult to say as I really do not have the equipment to measure it.   Static discharges will typically have <1ns rise times and their decay in in the 10s of ns.   Then there is a lot of current and noise that loves to corrupt the measurement. 

In this picture, I show a couple of home made targets I put together a to attempt to measure the pulse.   These discs are FR4 and there are several 1206 resistors that are embedded inside of it to attempt to minimize the inductance.


...

Sorry, I looked and have no scope shots of the data I took from it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 05, 2016, 02:36:49 am
are you going to try to find out what went wrong and fix it? just a question not a request
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 05, 2016, 03:01:04 am
are you going to try to find out what went wrong and fix it? just a question not a request

No problem.  I am sure that you are not the only one wondering.   The video was released with Part 1 in the title.  There will be a part 2 but at this time is it way to premature to say what that is going to cover.  Worst case, there will not be ANY UNI-T products in the house once I am done.   Give me some time to figure out my next step.   

In the mean time, there is still a UT10A on it's way and the 20 is sitting here waiting for me to run it.   Then there's the 210 project.   Lot's to do.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 05, 2016, 03:16:47 am
yeah, I was wondering if it's even repairable, because it went total dead, no errors or anything, but I'll wait you to organise yourself there, and the other content to come   :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 05, 2016, 08:18:10 am
Just an observation: The non-contact UNI-T clamp has more input protection than most UNI-T multimeters.

Does that make sense to anybody?  :-//

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 05, 2016, 08:43:47 am
This was a test I really thought was a waste of my time to even run as that starter is not much of a pulse.   

Do you think it's similar to the sort of sparks people can generate by walking on nylon carpet, etc?

Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on April 05, 2016, 10:08:20 am
Wow, that was a shocker and it didn't even get past a warm up.... :-BROKE :-+

Boot up times hardly count for much if shortly after you kick the bucket.... ::) :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 05, 2016, 12:20:26 pm
Just an observation: The non-contact UNI-T clamp has more input protection than most UNI-T multimeters.

Does that make sense to anybody?  :-//

I really believe they are attempting to improve their products.   

This was a test I really thought was a waste of my time to even run as that starter is not much of a pulse.   
Do you think it's similar to the sort of sparks people can generate by walking on nylon carpet, etc?
Here, with carpet, during the winter the air can become very dry and I get get some pretty good static going.   If we use the human body as a means of measuring the energy (because that is very scientific), I will say I have had a lot more pain touching things with my finger from a normal discharge than I have with this starter.   In the end, I really don't know.  The one thing I do know is that the vast majority of meters handle this transient with no problems.   

Wow, that was a shocker and it didn't even get past a warm up.... :-BROKE :-+

Boot up times hardly count for much if shortly after you kick the bucket.... ::) :P

I agree.  The better display, better user interface, added temperature port and other features mean nothing if it's dead.   

I did write UNI-T a few days ago about the display update rate and was hoping that even though the meter is now damaged that we could at least open some sort of dialog.   It is very rare when a company will respond to my emails but you never know.   
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on April 05, 2016, 03:19:19 pm
Yes, certainly can.

Quite shockingly poor protection, know one would know without this thread.  Uni-T can make good meters as its been the OEM for several Amprobe models, I have an older post on eevblog with copies of testing documents showing the OEM.

Joe, do you know the output voltage of your spark igniter?  Its really not supposed to kill the meter unless the input protection components didn't work for various reasons: counterfeit, wrong spec used, PCB defect etc.,.  The tear down you showed shows it should have worked.  It would be great for you to trace it out and zoom into the protection areas.

Too bad, it was even ETL certified and IP65.

The saga continues, no doubt. :popcorn:

This was a test I really thought was a waste of my time to even run as that starter is not much of a pulse.   

Do you think it's similar to the sort of sparks people can generate by walking on nylon carpet, etc?


Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 05, 2016, 05:43:22 pm
I did write UNI-T a few days ago about the display update rate and was hoping that even though the meter is now damaged that we could at least open some sort of dialog.   It is very rare when a company will respond to my emails but you never know.

Did you send them a link to this video?

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 05, 2016, 07:47:30 pm
joeqsmith, that was an excellent video! Nowadays anyone can slap a powerful Cortex A processor to handle a beautiful GUI, but the appalling susceptibility to transients only shows UNI-T is blatantly lying on their CAT Ratings.  :--

I would completely understand if they had marked this meter as a portable "lab meter" where you are not really required to have any ratings... Their webpage (http://www.uni-trend.com/en/product/2014_0711_586.html) does not mention any CAT ratings, but its manual (http://www.uni-trend.com/uploads/soft/wanyongbiao/UT181A--Manual-English.pdf) does.

I suspect they will eventually do the same releases as the UT-61: UT-181A, UT-181B, C, D... until it gets somewhere close to its alleged safety.
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on April 05, 2016, 10:19:51 pm
The CAT rating has nothing to do with being able to function after being hit with a high voltage. The CAT rating is for the safety of the user, not the meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 05, 2016, 10:36:53 pm
and end up with a $300+ brick...is kinda ouch!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 06, 2016, 12:08:30 am
Quite shockingly poor protection, know one would know without this thread.  Uni-T can make good meters as its been the OEM for several Amprobe models, I have an older post on eevblog with copies of testing documents showing the OEM.

Joe, do you know the output voltage of your spark igniter?  Its really not supposed to kill the meter unless the input protection components didn't work for various reasons: counterfeit, wrong spec used, PCB defect etc.,.  The tear down you showed shows it should have worked.  It would be great for you to trace it out and zoom into the protection areas.

When you look at how many meters survived this with no problems,  they certainly have a few examples they could have copied from.

I posted my homemade targets a page back and had looked for the data I took but looks like I did not save anything. 

Keep in mind, I am not sure that a hand held meter is even required to pass any sort of ESD event.   What I can tell you is looking at a manual from Fluke and Hioki, they both call out EN61326, which references 61000-4-2.  My guess is that the meters would fall under Annex A, criteria B.   Looking at the manual for the UNI-T,  I do not see a reference to an EMC standard, only for the safety.   The basic current wave shape for the -4-2 standard should be on-line.

I did write UNI-T a few days ago about the display update rate and was hoping that even though the meter is now damaged that we could at least open some sort of dialog.   It is very rare when a company will respond to my emails but you never know.
Did you send them a link to this video?

I wrote them a day before I posted the video, so no. 

joeqsmith, that was an excellent video! Nowadays anyone can slap a powerful Cortex A processor to handle a beautiful GUI, but the appalling susceptibility to transients only shows UNI-T is blatantly lying on their CAT Ratings.  :--

I would completely understand if they had marked this meter as a portable "lab meter" where you are not really required to have any ratings... Their webpage (http://www.uni-trend.com/en/product/2014_0711_586.html) does not mention any CAT ratings, but its manual (http://www.uni-trend.com/uploads/soft/wanyongbiao/UT181A--Manual-English.pdf) does.

I suspect they will eventually do the same releases as the UT-61: UT-181A, UT-181B, C, D... until it gets somewhere close to its alleged safety.
Thanks.  Glad you enjoyed it.  I really have no idea if any of the meters I have looked at would be considered safe or not.  Certainly, I have never thought of an ESD test as being safety related.

and end up with a $300+ brick...is kinda ouch!
Agree.  But maybe that grill starter test is just too harsh of an environment.


I thought someone would have ran these test and while searching, came across this:
http://www.bartek.com/Bartek/ESD.html (http://www.bartek.com/Bartek/ESD.html)
Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on April 06, 2016, 01:08:02 am


I thought someone would have ran these test and while searching, came across this:
http://www.bartek.com/Bartek/ESD.html (http://www.bartek.com/Bartek/ESD.html)

That Uni-T is pathetic, your tests has made me much less likely to recommend Uni-T.

The gun looks like a modified vinyl anti-static gun.
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 06, 2016, 01:28:30 am


I thought someone would have ran these test and while searching, came across this:
http://www.bartek.com/Bartek/ESD.html (http://www.bartek.com/Bartek/ESD.html)

That Uni-T is pathetic, your tests has made me much less likely to recommend Uni-T.

The gun looks like a modified vinyl anti-static gun.

yeah, I have an old eletronics magazine that shows one of these for vinyl, if I find it I'll post a pic
Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on April 06, 2016, 01:42:47 am


I thought someone would have ran these test and while searching, came across this:
http://www.bartek.com/Bartek/ESD.html (http://www.bartek.com/Bartek/ESD.html)

That Uni-T is pathetic, your tests has made me much less likely to recommend Uni-T.

The gun looks like a modified vinyl anti-static gun.

yeah, I have an old eletronics magazine that shows one of these for vinyl, if I find it I'll post a pic
We still use them in the lab for getting powders in the tube in hyper dry environments.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 06, 2016, 01:47:17 am
That Uni-T is pathetic, your tests has made me much less likely to recommend Uni-T.
The gun looks like a modified vinyl anti-static gun.

Vinyl? Post a little more info. 



Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on April 06, 2016, 01:52:29 am
That Uni-T is pathetic, your tests has made me much less likely to recommend Uni-T.
The gun looks like a modified vinyl anti-static gun.

Vinyl? Post a little more info.

VInyl as in vinyl records:

(http://img.usaudiomart.com/uploads/large/645566-zerostat_3_vinyl_antistatic_gun_by_discwasher_made_in_england.jpg)

(http://img.usaudiomart.com/uploads/large/645568-zerostat_3_vinyl_antistatic_gun_by_discwasher_made_in_england.jpg)

Also a video of one being used to break-up static charge.
https://www.youtube.com/watch?v=aq9RyIsTRUI (https://www.youtube.com/watch?v=aq9RyIsTRUI)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 06, 2016, 02:04:29 am
found it! and got some info too, the pic isn't great but...

the voltage output should be from 15 to 20.000 volts, it produces it by torsion of the piezo element
I think that's more stuff there, I need to dig deeper at my magazines, if I find some more usefull info I'll post it later
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 06, 2016, 02:23:58 am
Quite shockingly poor protection, know one would know without this thread.  Uni-T can make good meters as its been the OEM for several Amprobe models, I have an older post on eevblog with copies of testing documents showing the OEM.

Joe, do you know the output voltage of your spark igniter?  Its really not supposed to kill the meter unless the input protection components didn't work for various reasons: counterfeit, wrong spec used, PCB defect etc.,.  The tear down you showed shows it should have worked.  It would be great for you to trace it out and zoom into the protection areas.

When you look at how many meters survived this with no problems,  they certainly have a few examples they could have copied from.

I posted my homemade targets a page back and had looked for the data I took but looks like I did not save anything. 

Keep in mind, I am not sure that a hand held meter is even required to pass any sort of ESD event.   What I can tell you is looking at a manual from Fluke and Hioki, they both call out EN61326, which references 61000-4-2.  My guess is that the meters would fall under Annex A, criteria B.   Looking at the manual for the UNI-T,  I do not see a reference to an EMC standard, only for the safety.   The basic current wave shape for the -4-2 standard should be on-line.

Let me start with again, I have no idea what the meter are required to pass, if anything for ESD.   And again,  EN6132601:2013 Annex A calls for an 4KV contact, 8KV air criterion B.   Looking at 61000-4-2:2009, 4KV contact is level 2 and 8KV air is level 3. 

Taking the grill starter and roughly measuring the air gap when it will arc, assuming 33KV/cm.  Of course, we all know this is a swag.  I would estimate the peak is about 15KV.    :wtf:

OK, I know, the meters only rated to  :blah: :blah: :blah: and your hitting it with  :blah: :blah: :blah:, why would you ever think it would survive.....     Keep in mind, the product is not supposed to be damaged during this test.

Well, while everyone who asked, asked about the peak voltage.  Not one person asked me about the current.   Level 2, contact is 4KV and requires a first peak of 15A with a rise time of 0.8ns.  At 30ns it decays to 8A.  At 60ns it decays to 4A.

Measuring this is normally done with a target.  This is called out in the standards.  Of course, as a hobbyist I built my own.  So keep this in mind...  The target is 2 ohms and you follow this with a 20dB attenuator then less than 1 meter of good coax. The standard recommends RG400.  Then into the DSO.   Of course, you need a fast DSO to look at this.   

What I have is my homemade target.  I think this is 1206's or 0805s placed inside the PCB.   All in parallel to reduce the inductance.   As you can see from the picture, I use an SMA to couple to target to the attenuators.   In my case rather than 20dB (10x) I use 26dB.  Why?  Because as much fun as I am having destroying meters, I have no desire to damage my best DSO.   The is also a very fast clamp in-line with the DSO, just in case.  The attenuators are all Mini-Circuits and are rated to 6GHz.   I am using roughly 0.5 meters of RG400 cable terminated with SMAs.   This mess then connects to the 5GHz LeCroy 8500A, set to 20GS/s.   

Next, I hold the grill starter to the target and push the button.  That's it.   

Looking at the attached screen shot (which I just took so ignore that fact I am too lazy to set the clock) the peak is roughly 100mV.   So 0.1 * 19.19 = 2 Volts across our 2 ohm target or 1Amp peak.   Even a level 1 requires 7.5A!!   We can see at 30ns we are supposed to be at 8A but our signal is fully settled out by then as we only have a width of about 5ns!!

Now sure, we can say the peak, open circuit voltage is about double but the energy is not even in the ballpark.  Hope this helps answer anyone who has a question about this test.

I have added a picture of the test setup.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 06, 2016, 02:54:45 am
Interesting product.  I am old enough that I should have seen one, but never have. 

found it! and got some info too, the pic isn't great but...

the voltage output should be from 15 to 20.000 volts
I think that's more stuff there, I need to dig deeper at my magazines, if I find some more usefull info I'll post it later

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 06, 2016, 02:56:28 am
The CAT rating has nothing to do with being able to function after being hit with a high voltage. The CAT rating is for the safety of the user, not the meter.
Lightages, you are right. Despite this, it does not inspire much confidence if the meter does not survive in an extremely low energy scenario...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 06, 2016, 03:05:14 am
The CAT rating has nothing to do with being able to function after being hit with a high voltage. The CAT rating is for the safety of the user, not the meter.
Lightages, you are right. Despite this, it does not inspire much confidence if the meter does not survive in an extremely low energy scenario...
Oh come on, after watching three UNI-T meters fail this test including their top of the line one, I have the highest confidence that this brand will continue to fail these tests!   :-DD


Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 06, 2016, 03:14:07 am
I'm in doubt now, but I think even the Digitek survived the test or not? need to see the video again lol

yep  :-DD it did survive  :-DD

https://youtu.be/Ohk2dqsq7dM?t=6m23s

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 06, 2016, 04:30:20 pm
I am starting to suspect that even the Harbor freight stuff (http://www.harborfreight.com/7-function-multimeter-98025.html) would fare better than these Uni-T meters...
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 06, 2016, 10:27:45 pm
I am starting to suspect that even the Harbor freight stuff (http://www.harborfreight.com/7-function-multimeter-98025.html) would fare better than these Uni-T meters...

and you could throw it in the trash without any remorse, and a top end meter that can't take some stress, as Dave sayid before and he is absolutely right,  what a waist of money...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 07, 2016, 12:25:45 am
I am starting to suspect that even the Harbor freight stuff (http://www.harborfreight.com/7-function-multimeter-98025.html) would fare better than these Uni-T meters...

I don't think I have ever tested the Harbor Freight meter with the grill starter.   Does make you wonder.   

and you could throw it in the trash without any remorse, and a top end meter that can't take some stress, as Dave sayid before and he is absolutely right,  what a waist of money...

I think I will pick another one (HF) up for the pocket meter testing.   Cause you know that there is going to be some carnage during that test!  Two of the meters are UNI-T.   Did you know that you can always download that spreadsheet from the first post rather than hunting through the videos?   

Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 07, 2016, 01:38:49 am
I am starting to suspect that even the Harbor freight stuff (http://www.harborfreight.com/7-function-multimeter-98025.html) would fare better than these Uni-T meters...

I don't think I have ever tested the Harbor Freight meter with the grill starter.   Does make you wonder.   

and you could throw it in the trash without any remorse, and a top end meter that can't take some stress, as Dave sayid before and he is absolutely right,  what a waist of money...

I think I will pick another one (HF) up for the pocket meter testing.   Cause you know that there is going to be some carnage during that test!  Two of the meters are UNI-T.   Did you know that you can always download that spreadsheet from the first post rather than hunting through the videos?

yes I know, but it's .xls format, I need to find a plugin or something like that for firefox to open it, most stuff on the net like manuals and other stuff is PDF format so I open it directly in firefox. and about hf meter, is this thing survives the test it would be hilarious, at least if it doesn't, won't be a big loss, I'm kinda curious if you can repair the uni t, it was looking good compared with the fluke, the menus and etc
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 07, 2016, 02:19:16 am
yes I know, but it's .xls format, I need to find a plugin or something like that for firefox to open it, most stuff on the net like manuals and other stuff is PDF format so I open it directly in firefox. and about hf meter, is this thing survives the test it would be hilarious, at least if it doesn't, won't be a big loss, I'm kinda curious if you can repair the uni t, it was looking good compared with the fluke, the menus and etc

I have uploaded the last data I collected that included the UT181A.  I also converted the data to PDF.

thank you very much Sir, much apreciated  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: ProBang2 on April 07, 2016, 02:22:57 am

"yes I know, but it's .xls format, I need to find a plugin or something"

If you are using Windows, then there are 3 free solutions to look at .xls (Excel) files:

1) Download the free Excel-Viewer from Microsoft:
https://www.microsoft.com/pt-BR/download/details.aspx?id=10 (https://www.microsoft.com/pt-BR/download/details.aspx?id=10)

2) Register in the free Microsoft Cloud (5GB free cloud-memory) and open (/work with) the downloaded file there:
https://products.office.com/pt-BR/office-online?legRedir=true&CorrelationId=4f3ee5d7-73f2-4bfa-bbb6-4a1e9b9da2ed (https://products.office.com/pt-BR/office-online?legRedir=true&CorrelationId=4f3ee5d7-73f2-4bfa-bbb6-4a1e9b9da2ed)

3) Download and install the open source freeware Office-Suite from "Libre-Office". (Full Office-Software: Writer, Calculation, Presentation, Math...)
https://www.libreoffice.org/download/libreoffice-still/?type=win-x86&version=&lang=pt-BR (https://www.libreoffice.org/download/libreoffice-still/?type=win-x86&version=&lang=pt-BR)

Recommended: # 3
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 07, 2016, 02:58:54 am
I am starting to suspect that even the Harbor freight stuff (http://www.harborfreight.com/7-function-multimeter-98025.html) would fare better than these Uni-T meters...

I don't think I have ever tested the Harbor Freight meter with the grill starter.   Does make you wonder.   

and you could throw it in the trash without any remorse, and a top end meter that can't take some stress, as Dave sayid before and he is absolutely right,  what a waist of money...

I think I will pick another one (HF) up for the pocket meter testing.   Cause you know that there is going to be some carnage during that test!  Two of the meters are UNI-T.   Did you know that you can always download that spreadsheet from the first post rather than hunting through the videos?

yes I know, but it's .xls format, I need to find a plugin or something like that for firefox to open it, most stuff on the net like manuals and other stuff is PDF format so I open it directly in firefox. and about hf meter, is this thing survives the test it would be hilarious, at least if it doesn't, won't be a big loss, I'm kinda curious if you can repair the uni t, it was looking good compared with the fluke, the menus and etc

Roberto, perhaps this?
https://addons.mozilla.org/en-us/firefox/addon/docs-online-viewer/ (https://addons.mozilla.org/en-us/firefox/addon/docs-online-viewer/)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 07, 2016, 05:37:56 am
thanks guys, I'll have a look at these
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 07, 2016, 11:13:27 am
The 181A is given a drink and bullet to bite down on..   The 210E knows from experience that this can't be good!
Title: Re: Handheld meter electrical robustness testing.
Post by: Len on April 07, 2016, 08:17:34 pm
The 181A is given a drink and bullet to bite down on..   The 210E knows from experience that this can't be good!

Tell me when it's over. I can't watch.  :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 07, 2016, 10:25:10 pm
The 181A is given a drink and bullet to bite down on..   The 210E knows from experience that this can't be good!

damn, are going to use it for target practice???  :-DD  with a bullet like that, there won't be much left, well at least it isn't an AAS50 rifle  :phew:

from Hateful Eight  "Y'all keep your mouth shut and do what I tell ya'. Anybody opens their mouth, gonna get a bullet. Anybody moves a little weird....little sudden--gonna get a bullet. Not a warning. Not a question; a bullet. Let me hear you say, 'I got it'. "  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on April 07, 2016, 11:09:33 pm
How big are those clamp meters ?  :-//
If this listing below is any guide they must be huge, anyway race you to the rubbish bin.... :-BROKE

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 08, 2016, 01:31:34 am
We all bleed red .....     
(Except UNI-T which bleeds Fluke yellow!)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 08, 2016, 10:27:15 pm
any survivors?  :-DD what's next?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2016, 01:32:04 am
Spent the day with it.   Maybe in another day I will post part 2. 

I am still waiting on one of the pocket meters to show up before I do this review.   The 210E is getting no where.  The 181A is taking too much time.

any survivors?  :-DD what's next?
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 09, 2016, 01:44:19 am
when I saw the 181A with the bullet, I tought you would just trash it, I just asked because I tought that you really would targed practice on it
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2016, 01:58:50 am
I have done some pretty bad things to meters that were not worth the effort to repair.   High voltage with the Jacobs ladder, shot with arrows, dropped from the roof onto concrete, dremel tooled...   Shooting one is pretty high on the list but it will be a 12G at close range....   So stay tuned to see how it turns out..

when I saw the 181A with the bullet, I tought you would just trash it, I just asked because I tought that you really would targed practice on it
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 10, 2016, 12:39:15 am
Part 2 of my UNIT-T UT181A review. 

https://www.youtube.com/watch?v=1kYcY2ogmqo (https://www.youtube.com/watch?v=1kYcY2ogmqo)
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 10, 2016, 02:29:05 am
Again an excellent video, glad you could get it working again, and now with some voodoo magic  :-DD and like you sayd it's not acceptable that a meter like that is so sensitive to ESD and cheaper meters do survive just fine, very informative  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on April 10, 2016, 10:05:59 am
That DC DC converter likely failed because the ESD diodes to the ADC were feeding the pulse into the 3V3 rail, and this raised the output voltage of the regulator beyond what it could stand, or the internal ESD diodes avalanched and turned on the parasitic SCR inside it which killed it.  Easy to solve by simply having a small SMD diode to allow this energy to flow back to the battery across the converter ( it is step down so the diode will almost never be forward biased except in an ESD or overvoltage event), and add a little extra capacitance to the supply rails to tame the spike a little, just doubling the ceramic capacitors would do for this.
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on April 10, 2016, 08:57:22 pm
Great job remediating the problem. 

For other readers, a big difference between the tests is that static discharge waveforms are in nanoseconds while the impulse waveform are in microseconds.   So the energies involved relative to human injury is mJ for static versus J for impulses, but to high impedance electronics, its still deadly.  Why Uni-T didn't take it into account is puzzling given the effort to get ETL listed, typically the ETL consultant would have mentioned it.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 10, 2016, 11:07:26 pm
Thanks for the comments.   Just in case the UNI-T group ever visits,  if there is a rev B of this meter a few things I would like to see are:

Certify to EMC standard 61326.
Adapters for the European charger.
Offer a spare battery as an accessory.
Store the current settings on power down or function change (like the BM869s).
Better material for LCD cover (prone to scratching). 
When logging data with Windows, download the battery life.
Open source the interface or at least provide a communications library for it.

I am not sure how well this thing would  survive a drop test.  Maybe offer a slip on rubber sleeve as an accessory.

All in all, I really like the meter for hobby work but I would not recommend it with it being as susceptible as it is to static.

Today, I turned on the Fluke reference for an hour with it set to 1mv.  I then connected the Fluke to the UT181A (which was just sitting out in open air).  I then let it run for five and a half hours collecting the data.   Keep in mind the house temperature varies throughout the day.   It appears pretty stable.  Then again, they spec a temperature coefficient of 0.1 * +/-(0.025 +20 counts)/deg C.   

Plot is showing +/-3uV   
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on April 10, 2016, 11:18:16 pm
Thanks Joe, this was an excellent effort on your part and it made for a great video, it clearly shows that improvements for reliability can be made to some meters and perhaps some manufacturers who see this may take it on board.

I did like the way you utilised the hold button on the first meter before switching to the second to retain the measured value for comparison, I wish others would do the same thing when comparing meters so we don’t have to remember what the previous meter displayed, this was a nice touch.

To sum up……. :-+ :) ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 10, 2016, 11:23:08 pm
The meter goes into a low power mode when data logging.  I was hoping to finish off the battery this weekend but it still has a fair amount of charge left.   

I put the meter into my temperature chamber  :-DD (cardboard box with two layers of foam, fan and heater).   Normally I run this off a PC but for this, I just ran it open loop, using the Brymen to monitor the temperature next to the meter.

I started out at room temp (21.4C).   I then just set the heater to a fixed current.   At 18 minutes, it was at 32.2 C.   At 1 hour it reached 34.2 C.  At least a 10 deg rise.   

After three days of testing and around 30 hours of hard time, the last picture shows the battery remaining.   They do not talk about the battery life but I would guess based on my normal use, its about 40 hours between charges.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Maxlor on April 10, 2016, 11:35:02 pm
That was interesting to watch, thank you for making the video. I'm a bit puzzled though by one thing: Obviously Uni-T put in some effort into making the meter robust to transients, so how could they miss the ESD susceptibility? Or rephrased, how would the meter survive transients, but not ESD events? Is this because of the (presumed, on my part) much smaller rise time of static discharges?

In any case, it feels like they're stepping up their game. If you look at what they've been doing so far, the next generation of meters in a couple of years will probably be hard to fault, but cost a third of what a Fluke costs. Which will hopefully make Fluke and others think about some strategic improvements as well. And your videos as well as those of your fellow videobloggers sure help with making issues more visible :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 10, 2016, 11:37:08 pm
Thanks Joe, this was an excellent effort on your part and it made for a great video, it clearly shows that improvements for reliability can be made to some meters and perhaps some manufacturers who see this may take it on board.

I did like the way you utilised the hold button on the first meter before switching to the second to retain the measured value for comparison, I wish others would do the same thing when comparing meters so we don’t have to remember what the previous meter displayed, this was a nice touch.

To sum up……. :-+ :) ;)

Using the hold was an excellent idea!   Thank you very much for that.

The video ran a little longer than I had hoped.  It's hard to condense three days into under an hour and know what to show.  Enough people had asked about the peak voltage that I thought it would be good to at least make an attempt to explain the standards and how the grill ignitor compared with it.   

I wanted to make sure people understood that the meter was fully functional after the repairs and that when I repeated the grill starter test that I was not holding back.   Adding the Harbor Freight meter at least gave some perspective that the grill starter would still damage a low end meter.   After running at 15KV, connecting the UT61E was just to show what sort of signal was coming out of the generator.   Still not a lot of energy but that has never been a goal. 

So thanks again for that little tip.   If anyone has a question about the meter or would like to see some other test ran on it, let me know and I will see what I can do.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 10, 2016, 11:51:45 pm
That was interesting to watch, thank you for making the video. I'm a bit puzzled though by one thing: Obviously Uni-T put in some effort into making the meter robust to transients, so how could they miss the ESD susceptibility? Or rephrased, how would the meter survive transients, but not ESD events? Is this because of the (presumed, on my part) much smaller rise time of static discharges?

In any case, it feels like they're stepping up their game. If you look at what they've been doing so far, the next generation of meters in a couple of years will probably be hard to fault, but cost a third of what a Fluke costs. Which will hopefully make Fluke and others think about some strategic improvements as well. And your videos as well as those of your fellow videobloggers sure help with making issues more visible :)

Thanks. 

I dug into the standards and still to be honest, I have no idea if they need to meet the 61326 standard.  All I ever seem to hear about is safety and 61010.  So, maybe they are fine not meeting it.   

I think what Saturation posted is spot on.  These are two completely different transients and what works for one may not work for another.   One thing the EMC standard is clear about, when it comes to ESD the product can not be damaged.  When we look at the 61010, I am still not sure if this is a requirement or not. 

Great job remediating the problem. 

For other readers, a big difference between the tests is that static discharge waveforms are in nanoseconds while the impulse waveform are in microseconds.   So the energies involved relative to human injury is mJ for static versus J for impulses, but to high impedance electronics, its still deadly.  Why Uni-T didn't take it into account is puzzling given the effort to get ETL listed, typically the ETL consultant would have mentioned it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2016, 10:35:41 am
Last of the pocket meters made it in.   Both the UT181A and the UT10 were ordered on the same date.  Maybe in a few weeks I'll have a chance to look at them.  Time to have a look at that 210E.

I did end up sending UNI-T a second email with links to the videos and my recommendations for the 181.  Who knows, maybe we will see a UT181B in the future. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2016, 09:54:34 pm
What happens when your meter is used to measure the output of a microwave oven transformer?   

https://www.youtube.com/watch?v=eY5Rh2gokgg&feature=youtu.be (https://www.youtube.com/watch?v=eY5Rh2gokgg&feature=youtu.be)

And you thought my tests were harsh!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 13, 2016, 10:56:57 pm
ahh, it doesn't show the test, just the damaged meter...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2016, 11:22:56 pm
Yea, I know!  We were shorted!  I was reading the description.    If it were me, I would have left the cover off, pointed the camera at it, then connect the thing back up.    :-DD :-DD

I need a microwave transformer...

This happened to my multimetr after I have tried to measure voltage on secondary winding of a samsung microwave owen after replacement of a burned glas fuse. I do not know what I was fhought about that moment, but as I red later the voltage level on it is about 3 kV. Thanks god I still have both of my hands. As autopsy shown, it is only 1 ptc and couple of resistors inside, and this is all input overvoltage protection of this multimeter. I wrote an email to manufacturer but they use "ostrich policy" in their job. So, I writing about this for those people, who is going to buy this fake rated device. Do not do it, even for low voltage works, because some day, somehow, you may forget about CAT ratings, and stick it to mains, or worse house incoming power supply 380 V, but nobody will tell you that will happen after that!

Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 13, 2016, 11:28:51 pm
heh, I have one here lol, from an old 1600 watts microwave, the capacitor is rated for 2400 VAC , the magnetron too and no I won't kill my meter with it   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 14, 2016, 12:47:30 am
Looks like a good sized transformer.   I wonder if any handheld meter would survive a 1 minute hookup.   
Title: Re: Handheld meter electrical robustness testing.
Post by: RobertoLG on April 14, 2016, 02:19:09 am
Looks like a good sized transformer.   I wonder if any handheld meter would survive a 1 minute hookup.

ya, it's about 6 kilos, the microwave was almost as big as an old CRT TV, with no spinning plate.  the only way to find out is to do the test lol, and that guy from the video learned a lesson he'll never forget at least.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on April 15, 2016, 06:32:20 pm
I have a microwave sitting around........ Should i connect a cheapie meter I do not like to it on DC volts and see where the smoke comes out?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 15, 2016, 08:23:46 pm
Or take its guts, create a cheapie microwave gun and aim at the unloved DMM.

Something similar as to what these bozos did a while ago...

http://gizmodo.com/this-kid-took-apart-a-microwave-to-create-an-insane-an-1612804394 (http://gizmodo.com/this-kid-took-apart-a-microwave-to-create-an-insane-an-1612804394)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 16, 2016, 03:33:33 am
Looks like TME is selling the UT71D for $170 US.  Not the cheapest handheld to kill this way.   
Title: Re: Handheld meter electrical robustness testing.
Post by: gameru on April 16, 2016, 04:03:01 pm
Looks like TME is selling the UT71D for $170 US.  Not the cheapest handheld to kill this way.

Only a couple things are cheap on TME.It's a good shop,but with high prices
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 01, 2016, 05:28:36 am
A viewer had asked about making lower current measurements in the 4 to 20mA range using the Fluke 17B+.   

https://www.youtube.com/watch?v=89HDlSq8WEg&feature=youtu.be (https://www.youtube.com/watch?v=89HDlSq8WEg&feature=youtu.be)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 01, 2016, 05:51:17 am
Nice use of the current shunt on the Fluke 101.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 01, 2016, 03:33:50 pm
With the 4-20, I would think the risk would be fairly low but you never know.   

Nice use of the current shunt on the Fluke 101.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 01, 2016, 06:34:44 pm
Nice use of the current shunt on the Fluke 101.  :popcorn:
With the 4-20, I would think the risk would be fairly low but you never know.   

What's the risk? A burnt out resistor?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 01, 2016, 07:39:07 pm
I'm sure you can find a suitable high power shunt if you know the current range:

eg. http://www.ebay.com/itm/320757994835 (http://www.ebay.com/itm/320757994835)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 01, 2016, 08:58:14 pm
Working in an industrial environment and hooking up to anything with an unprotected device would have a risk.   Assuming your working in the range of 24V or less would seem like a risk.  With what I show, there is no blast shield, no fuse, the wires hang right out there for you to touch and the banana connectors are not what should be used.  A clamp would be much safer choice and because you are not going in-line would make things go quicker.   

Again, I think the risk would be fairly low but buying a meter that has all the protection built-in seems like a small price to pay if this is your job. 

Nice use of the current shunt on the Fluke 101.  :popcorn:
With the 4-20, I would think the risk would be fairly low but you never know.   

What's the risk? A burnt out resistor?

Title: Re: Handheld meter electrical robustness testing.
Post by: blacksheeplogic on May 02, 2016, 01:48:20 am
Working in an industrial environment and hooking up to anything with an unprotected device would have a risk.   Assuming your working in the range of 24V or less would seem like a risk.  With what I show, there is no blast shield, no fuse, the wires hang right out there for you to touch and the banana connectors are not what should be used.  A clamp would be much safer choice and because you are not going in-line would make things go quicker.   

Again, I think the risk would be fairly low but buying a meter that has all the protection built-in seems like a small price to pay if this is your job. 

If you are measuring inline (not using a clamp) a DMM with a ma range is probably a good option if you have any concerns first. A number of process meters won't appreciate any excessive voltages on the terminals. Both of mine are rated for 30V/24ma MAX on the terminals with the meter being essentially a very expensive fuse in the case of an overload.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 05, 2016, 01:23:54 am
I'm sure a few of you are wanting to see some meter carnage!    After all, watching a UNI-T survive 15KV gets pretty boring.   

I finally broke out the pocket meters and did a quick check on them.  Suddenly the Harbor Freight free meter does not seem so bad.   These are all CAT II 300V rated but my plan is to not change anything in the test setup.   They are small and while I have not had them apart yet, I have to believe these things are going to make a mess.   

Maybe over the weekend I can get something together.   So stay tuned...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 06, 2016, 11:42:47 am
Having a look at the new pocket meters.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 07, 2016, 04:58:16 pm
Much to my surprise, one of the pocket meters has actually been holding up rather well.   Imagine if you made some "high end" meter and it could not handle what a sub $20 CAT II pocket meter could handle.  Should have everything wrapped up today.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 07, 2016, 07:48:39 pm
The last meter just won't die. I have the Dremel, X-acto and dope out.   Time for a break while things dry....   
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 07, 2016, 08:38:37 pm
The last meter just won't die.
Sub $20 meter....... :wtf:  :o

Looking forward to this vid....... :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 08, 2016, 01:45:43 pm
It finally died.  However there's not working dead, then there is 600 Joules of dead.    :-DD     Looks like one more day of testing.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 08, 2016, 06:53:43 pm
It's in the computers hands now.  I just packed it into one 40 minute video that I will upload later today along with a new spreadsheet.   

On the plus side, I doubled down and used both the modified UT181A and the Brymen as a side-by-side reference.  Having used the 181A for a few weeks now, I hope that UNI-T releases a B model that addresses some of my concerns because I rather like the meter in some sick, demented way...

Looking down the road, there are only a few meters that I would like to add to the list.  One would be a Gossen, the other Dave's fat boy custom meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on May 08, 2016, 07:34:39 pm
You think Dave's meter has a chance of surviving at least half way through? Should at least meet the CAT ratings though.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 08, 2016, 10:36:42 pm
I'm sure it will meet the standard the way they are interpreted.   Maybe once things get closer, Dave will fill us in on his take about some of these details.  He has certainly reviewed enough meters and done several videos where he mentions fuses, MOVs, GDTs, creepage, clearances, layout......   Should be some what of a multimeter expert.   If his goal is to have a product that is robust as a $20 pocket meter, I'm sure he will make it happen.   


As far as my guess on how it would do against the meters I have tested, we would have to run one.  My track record is not very good.   A few examples:

Will the Fluke 87V survive the same transients the Fluke 101, 107, 115, 17B+ survive.  My guess would have been a big yes. 

Will the AMPROBE AM530 which costs about double the AM510 be able to survive the same levels. My guess was the 530 would far exceed the 510.     

Will the UNI-T UT181A, their top of the line meter,  survive an low energy ESD event.   My guess was all day long. 

You think Dave's meter has a chance of surviving at least half way through? Should at least meet the CAT ratings though.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 08, 2016, 10:51:49 pm
If you want to see some low cost pocket meter carnage, here you go..

https://www.youtube.com/watch?v=QNRFTMk8MVI (https://www.youtube.com/watch?v=QNRFTMk8MVI)

The updated spreadsheet is also available. 
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 09, 2016, 01:43:57 pm
Gave one of those Victors to a mate years ago and saw him get it out of his "good stuff" drawer the other day for some checks on auto wiring. That it was still going strong did surprise me at the time but not so much now after noticing that it measured up as reasonably accurate against the others you tested.

That they all didn't fail at 1.5kV was astounding.  :scared:

Great stuff as always Joe.  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 09, 2016, 04:37:13 pm
Thanks.   I was thinking the two UNI-Ts would not survive the grill starter.   Just shows a meter with no MOVs can take a fair amount of abuse.  Maybe by design, but my guess is they got lucky this time.   Sad the 181A with all of it's fancy protection could not take the abuse.   But the layout has to be done right.....

That they all didn't fail at 1.5kV was astounding.  :scared:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 09, 2016, 05:48:50 pm
Interesting that some of them actually blew the case open when they failed even though it's still in the "low energy" range.

I wouldn't like to have one in my hand when that happens.

(More proof that the magnetic hanger supplied with high-end meters is really a safety feature, not just a convenience)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 10, 2016, 12:14:56 am
I keep waiting to see one actually open up all the way but my setup just does not pack that big of a punch. 

Interesting that some of them actually blew the case open when they failed even though it's still in the "low energy" range.

I wouldn't like to have one in my hand when that happens.

(More proof that the magnetic hanger supplied with high-end meters is really a safety feature, not just a convenience)


Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on May 10, 2016, 12:34:22 am
How would this thing below go ?, I had a play with one of these recently only for a few minutes and for a couple of awkward applications I can see a spot for one in my toolbox, they are around thirty odd bucks I think and sold under many names including Mastech.

 
Title: Re: Handheld meter electrical robustness testing.
Post by: smithnerd on May 10, 2016, 12:39:57 am
Any chance of some hi-res pictures of what's left of the VC921 PCB?

That model has been discussed here before, but the PCB looks to have been redesigned:

https://www.eevblog.com/forum/testgear/victor-vc921-pocket-multimeter-worth-a-bash/ (https://www.eevblog.com/forum/testgear/victor-vc921-pocket-multimeter-worth-a-bash/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 10, 2016, 02:12:22 am
Have a look at these.

Any chance of some hi-res pictures of what's left of the VC921 PCB?

That model has been discussed here before, but the PCB looks to have been redesigned:

https://www.eevblog.com/forum/testgear/victor-vc921-pocket-multimeter-worth-a-bash/ (https://www.eevblog.com/forum/testgear/victor-vc921-pocket-multimeter-worth-a-bash/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 10, 2016, 02:31:42 am
There's lots of different ones that look identical outside the color.  Like the MS8211 and the 8211D.  Some show CAT II, some CAT III.  $22 to $50 depending who sells it.   

How would this thing below go ?, I had a play with one of these recently only for a few minutes and for a couple of awkward applications I can see a spot for one in my toolbox, they are around thirty odd bucks I think and sold under many names including Mastech.
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on May 10, 2016, 02:12:20 pm
Great video Joe, thanks again.  Given how less robust these DMMs are designed it becomes like a teaching video of where and how they fail, and mitigating one failure can just expose another.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 10, 2016, 05:00:27 pm
Thanks. 

Just an FYI.  Notice that I had marked the UT10 failing at 4KV when it broke down but when I ran the HIOKI I marked it as a pass.  I'm sure this will be a source of confusion.   When I ran the UT10, I took it to 5KV and knew it was not going to become non functional with the energy levels I test with.  Like the HIOKI, I wanted to know if I prevented it from breaking down, could it be ran at a higher level.   To be sure, I reset the generator to 4KV while I was making the changes as the meter did not appear to breakdown at 3K.  Once I had reworked the meter three times, it because permanently damaged.   The HIOKI on the other hand actually continued to survive after I had increased the creepage with the added plastic.   

I think in the start of these tests I was looking for any sort of a breakdown as a failure.  Of course, I also changed the matrix several times as I was sorting out how much an average meter could handle and how much time I wanted to spend finding their limit.  Using the scope is how I was judging if a meter started to breakdown but the scope and visual does not insure it.  I started looking for permanent damage to judge a pass/fail.   This is why so many meters early on were hit over and over when I knew they were arcing internally.   The UNI-T fan boys did not like their 139C getting treated like this.    :-DD    And of course, safety was never a concern....

I did get a comment about rotating the selector switch of the UT20 while it was obviously arcing.  No gloves and such.  If I were plugging them into a wall socket here, I would have something over my hands but the max current I can get out of the generator is only a few hundred mA and I set the trip point to 40 or so.  They also noticed that when I run the 1/2 cycle simulator, I only point to the meters with that long discharge probe.   When I play with that setup, I stand off to the side and back on the other side of the room just in case.  So far, the really has not been a case where I was concerned.  I think the worst was blowing up the glass fuse in the VICI.  I knew that was going to make a mess and closed the door. 

Great video Joe, thanks again.  Given how less robust these DMMs are designed it becomes like a teaching video of where and how they fail, and mitigating one failure can just expose another.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 11, 2016, 09:23:16 pm
Joe, one more great video, thank you.

My cynical side tells me the short creepage in the UT-10 is in fact the DMM protection circuit...  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 12, 2016, 12:44:22 am
My dark side says they are not that smart but it's possible.  If I ran that half cycle line simulator on a stock one, it would have cut loose.

Someone just asked me about the AM510s capacitance range.  I looked it up and see they show 4000uF on their site.
http://www.amprobe.com/amprobe/usen/digital-multimeters/am-500-digital-multimeter-series/amp-am-510.htm?pid=74033 (http://www.amprobe.com/amprobe/usen/digital-multimeters/am-500-digital-multimeter-series/amp-am-510.htm?pid=74033)

Attempted to read a 1000uF with mine and it over ranged.  Tried it on 5ky's AM530, no problem.   I tried a few tests and it over ranges at 100uF.   I looked in the manual that was shipped with the 510 and it states 100uF max.   So their website is wrong! 

They may offer a newer version of the AM510 than the one I bought.   The manual for the 530 shows 4000uF.  I ran 5Ky's against the Brymen at 2200uF and it's close but I had done a complete alignment on that meter after I damaged and repaired it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 12, 2016, 02:04:36 am
Joe, the online version of the manual (http://content.amprobe.com/manualsA/AM-510_Commercial-Residential-Multimeter_Manual.pdf) also says 100uF, thus I suspect the website suffered a Ctrl+C Ctrl+V issue...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2016, 03:29:00 pm
Interesting link showing a commercial generator.   Follow their other link where they modify it.    Imagine some of these low end meters on that setup!   

http://www.electricstuff.co.uk/surge.html (http://www.electricstuff.co.uk/surge.html)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2016, 04:37:24 pm
After testing so many meters, I have a fair number of test leads.  The meters get recycled but I hung onto the leads thinking I may do something with them.   

One way to test them would be to put some DC current through them.  The HF meter for example can measure up to 10A.  I would think the leads could handle at least 12.   

Another may be a pull test on the connections.   

Maybe I apply that half cycle transient through them without a fuse.
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on May 14, 2016, 05:31:44 pm
Hi Joe, IIRC the IEC safety requires a sustained 10-15kV for test leads for working voltages of 1kV with potential breakdown test points in various locations and mechanical stress configurations.

Here's the full suite as applied to Amprobe test leads. 

After testing so many meters, I have a fair number of test leads.  The meters get recycled but I hung onto the leads thinking I may do something with them.   

One way to test them would be to put some DC current through them.  The HF meter for example can measure up to 10A.  I would think the leads could handle at least 12.   

Another may be a pull test on the connections.   

Maybe I apply that half cycle transient through them without a fuse.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2016, 06:16:02 pm
 :-+  They drop test probes???!!!  :-DD :-DD  Pretty sure I could perform that test at home.   

I am looking at page 19.  Wow!!   So am I reading this right.  For the cable they show 29.0mm for both the creepage and clearance.  Then we see a test voltage of up to 14880 for the cable.   The sub-clause they refer to is 6.4 (for example) which refers to section 6.8 

"Solid insulation between ACCESSIBLE parts and HAZARDOUS LIVE parts shall pass the voltage test of 6.8 for BASIC INSULATION"   

In 6.8.4
"Voltage tests are applied, using the values specified in table 9. No breakdown or repeated flashover shall occur. Corona effects and similar phenomena are disregarded."

Then going to table 9, they step from 20 to 25 to 30mm.   For 29mm, I would have guessed they would use 30mm which calls for a AC peak 50/60 Hz or DC or 17.9KV.  For AC RMS, they show 12.6KV.   

I have no idea where the 14880 came from.   :-//     

Hi Joe, IIRC the IEC safety requires a sustained 10-15kV for test leads for working voltages of 1kV with potential breakdown test points in various locations and mechanical stress configurations.

Here's the full suite as applied to Amprobe test leads. 
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on May 15, 2016, 02:48:35 pm
Yes, I think a bottom line is test leads are pretty robust for DMM applications at 1kV given how overrated the requirements are.  I guess this takes into account user abuse [ e.g. yanking, pulling], and field wear and tear.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 15, 2016, 11:09:11 pm
Some of the leads from the free Harbor Freight meters, I don't think would handle the 10A.   I have a few sets of these I could try.   

In the report you linked, strange that they show rms/peak/dc but the standards call out a different number for rms and dc.   Strange.   For 30mm using the 1.5/50 impulse, they call out 23.3KV for 30mm.    I could run them on that generator and if they fail, that would be a good indicator there is a problem with them.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 18, 2016, 03:49:23 am
Made up some adapters that will allow me to place the probes in line with some sort of current source. 

My plan is to twist the probes together and hit them with the older generator with it set to the 15KV.  The probe tips will not be connected to anything.   Not even close to the voltage levels called out in the standards require but none of my testing ever is.

Then I plan to have some sort of computer programmable current source that will step the current and hold it for some time.  It will increase the current until the probes open up or I run out of current.   
 
Any probes that I can't damage that way, I plan to just connect across the half cycle generator.

May change the order. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 20, 2016, 12:41:37 am
Finished with the current source test setup.   I ran some tests with it using a few different probes and the differences are pretty dramatic.   I already melted one lead (in the range it was rated for!). 
Title: Re: Handheld meter electrical robustness testing.
Post by: Maxlor on May 20, 2016, 09:32:36 am
Finished with the current source test setup.   I ran some tests with it using a few different probes and the differences are pretty dramatic.   I already melted one lead (in the range it was rated for!).
Tease!

Looking forward to the video :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 03:03:58 am
 :-DD  I am just trying to get a feel for how it is all going to work.    Say you have two meters.  Both have a 10A current input.  You would sort of expect the leads that were supplied with the meter to handle 10A forever.    You would expect the leads would not drop too much voltage and dissipate a lot of heat.     But some brands seem like they have leads that would not even handle 5 Amps for an extended period.     One I put 50 through!   Yea, that's 50 Amps and it did not open up!   One was very cheap, the other a name brand.     

The software I wrote will record the data that is collected for each lead and allow me to view all of the probes performance at once.  It would also allow me to use the data to compare other leads later on..

When 5KY provided me with the meters, he did not supply the leads but it does appear that there many of them are purchased through the same supplier.    The other problem I see is some of the leads are not marked and I am not sure what meter they came with.   Depending how this works out, I may add lead testing to any reviews I do down the road.
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on May 21, 2016, 11:49:50 am
Wow.  If those leads are NRTL certified that would be a big problem.

Finished with the current source test setup.   I ran some tests with it using a few different probes and the differences are pretty dramatic.  I already melted one lead (in the range it was rated for!). 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 01:36:41 pm
I have no idea if any of these probes are certified.  They have a CE mark on them and most will state CAT ...   

Looks like a nice day outside.  I have my wireless router and my tablet PC ready....   The indoor testing is first.  Here is the line up.  All virgin except I plan to use one of my own set of probes that I normally use as a sort of base line.   



Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 21, 2016, 01:57:18 pm
Fry up at Joes place everybody, bring your own plate, knife, fork and .... :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on May 21, 2016, 02:12:44 pm
Any results would certainly be helpful!  FWIW all Fluke and Amprobe branded probes are NRTL.

I have no idea if any of these probes are certified.  They have a CE mark on them and most will state CAT ...   

Looks like a nice day outside.  I have my wireless router and my tablet PC ready....   The indoor testing is first.  Here is the line up.  All virgin except I plan to use one of my own set of probes that I normally use as a sort of base line.   




Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 21, 2016, 03:51:38 pm
:-DD  I am just trying to get a feel for how it is all going to work.    Say you have two meters.  Both have a 10A current input.  You would sort of expect the leads that were supplied with the meter to handle 10A forever. 

A lot of those meters say things like "10A for 10 seconds maximum" in the fine print.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 04:00:41 pm
In the video I will provide the CAT rating, current rating and the wire insulation OD?   I may measure the length as well.   

I am leaving the probes all bundled up for the HV test basically trying to get a worst case condition.   

Any results would certainly be helpful!  FWIW all Fluke and Amprobe branded probes are NRTL.


For the high current test, I will not be using a meter.  I would have jumped out the fuses for this test anyway.  No plans to pussy foot around.  I will run one lead at a time.   I am planning to start at 2A then increase every 30 seconds by 2A.   So say 40A or 20 steps, so 10 minutes per probe.  I plan to measure the voltage drop across the test leads and the current to get the power dissipated.   The whole setup is controlled by a computer so I will just sit back and monitor the action.   

The 40A I am not so sure about.  The current source is no problem.   Using some 6AWG with my custom made connectors and the power supply is a couple of KW.   I guess we just see how it goes.   If the leads handle 40, I may increase it to 80 or 100.   :-DD  The sun is out and we have a bit of wind.   It's a perfect day for it. 

A lot of those meters say things like "10A for 10 seconds maximum" in the fine print.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 04:10:49 pm
I kept 5KY's UT61E for a mechanical sample because it is such a popular meter.  I could jumper out the fuse on this meter and run it.  I can see someone doing something like this in real life.   

Well the coffee is gone, time to get back to work.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 21, 2016, 04:29:26 pm
I kept 5KY's UT61E for a mechanical sample because it is such a popular meter.  I could jumper out the fuse on this meter and run it.  I can see someone doing something like this in real life.   

So can I  :-DD

Last time I did "multimeter workshop" at the Arduino club nobody had a multimeter with an intact fuse on the 200mA range. Not even one.   :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 06:33:07 pm
What would a person use?  Maybe a bolt?  Too hard to find something that fits.   Wire!!!   So RG58 braid packed in there. 

I'm sure the UNI-T clan is going to be all up in arms.  I can hear it all now.  "Only and idiot would do something like this!!"   :-DD :-DD  Maybe the professional trolls will even chime in on the Youtube comments....

Time to head outside...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 21, 2016, 08:30:16 pm
What would a person use?  Maybe a bolt?  Too hard to find something that fits.   Wire!!!   So RG58 braid packed in there. 

The traditional fuse replacement (in the USA) is a .22 bullet.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 08:38:43 pm
I checked, it was too short and I don't own a 22 mag.  :-DD

Testing is going pretty good.  I am running them all to 20A to start.  Amazed what a difference I am seeing.   I get the bad feeling that like when the 87V did so poorly, the high end leads may not be the best....   Lots more to go. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2016, 11:58:39 pm
What are your tests leads insulation made of?  Vinyl?    Silicone?  Other?   
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on May 22, 2016, 12:20:31 am
Like many others here I have numerous meters with various leads sets, funnily enough I very rarely if ever use the original leads that come with the meters regardless of the quality, I've never been much of soft silicone fan because I find that out in the field they tend to get caught up on anything and everything, my preference is for a less flexible lead with a smooth rather than sticky insulating material, each to their own.

Years ago I bought 20 sets of cheaper average quantity leads just because they had all of the attributes I was looking for and they get given a hard time in factories, plants and machine shops with chompers all over the place. They are similar to the UNI-T UTL-23 leads and the specs say ABS, we bought a number of their meters years ago and most went back but I didn't mind the leads at the time so went hunting and loaded up for peanuts, otherwise the TL-71 leads that come with our 117's are very nice but I save the good leads for special occasions.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 22, 2016, 03:56:56 am
I was thinking asbestos after today.

All of the testing is done and I have started editing the video.  I need to work out some sort of conclusion.  Hope to have it uploaded by Monday.  In the mean time, here is a little spoiler.  If horizontal is samples, I bet you can guess the vertical axis.   The two data sets are from the same brand of probe.  One is fairly old, the other is the latest and greatest.....   
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on May 22, 2016, 05:43:42 pm
What would a person use?  Maybe a bolt?  Too hard to find something that fits.   Wire!!!   So RG58 braid packed in there. 

I'm sure the UNI-T clan is going to be all up in arms.  I can hear it all now.  "Only and idiot would do something like this!!"   :-DD :-DD  Maybe the professional trolls will even chime in on the Youtube comments....

Time to head outside...

Standard fuse replacement when I was younger was to wrap the fuse with some wire, typically some 2.5mm wire, or the foil out of a cigarette pack you grabbed off the nearest smoker.

For the larger fuses a 7.65mm R5 round was perfect as a replacement, there were always empty cases around.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 22, 2016, 09:45:33 pm
Some major abuse of some perfectly good, brand new test leads.   

https://www.youtube.com/watch?v=fQowDZstguw (https://www.youtube.com/watch?v=fQowDZstguw)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 23, 2016, 12:55:39 am
Not the fry up that I would have expected with any of the cheap leads and that most withstood up to 20A or more is staggering.

Joe, did you do any probe lead length comparison that could have affected Vdrop results ?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 23, 2016, 02:18:42 am
I had ran a few tests ahead of running the probes.  I calibrated the voltage using the Fluke reference.  The shunt used was decent.  Then I showed the setup with the UT210E.  I am also fairly confident that the majority of the loss was in the test leads cables and not the 6 AWG cables or my connections.  Of course there will be errors but my goal was really to try and test them the same and compare results..

So like you, not only was I also very surprised just how far I could push some of the test leads, I am also confident in the numbers I was throwing up.   

Seeing that very old Fluke lead holding 60A for that length of time was very impressive!   70Amps to finally fuse it!   And this is why you want a fused meter and don't want to put the wrong fuse or worse, defeat your fuse even if they do cost a few dollars each!   Better than burned hands!
 
As always, there were some mistakes during the video but the obvious one was I show the gray Mastech probes were the best, not the plain black and red.   Too much sun. 

Without knowing anything about the wire they used, its pretty hard to say anything about the resistivity.   Below, the brand, overall length, wire insulation OD, Resistance at 4A, Gold Plate

CENTECH, 32", 0.02", 0.375
Agilent, 55", 0.05", 0.047
Fluke (101), 55", 0.05", 0.047
HIOKI, 43", 0.04", 0.043,  gold
AMPROBE, 42", 0.04", 0.041
Brymen, 46", 0.045, 0.033, gold
KLEIN, 41", 0.045", 0.150
Mastech (plain), 40", 0.04", 0.074
VICI, 42", 0.042", 0.084
Mastech (gray), 41", 0.04", 0.026
ProbeMaster, 46", 0.04", 0.031, gold



Not the fry up that I would have expected with any of the cheap leads and that most withstood up to 20A or more is staggering.

Joe, did you do any probe lead length comparison that could have affected Vdrop results ?
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 23, 2016, 02:26:52 am
Thanks Joe, great work as always.  :-+

That there's a range of 13" over the lead lengths is surprising  :o so is there any sense in recalculating the results to reflect the lower R/foot leads.  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 23, 2016, 02:40:07 am
I would need to know the resistivity of the wire. 


Ignoring the KLEIN and Centech test leads, the following graph shows the remaining probes voltage drops at 4 Amps.   Note that the sample time is roughly 10Hz, or about 10 seconds of data.   For the most part, the readings are fairly stable.




Thanks Joe, great work as always.  :-+

That there's a range of 13" over the lead lengths is surprising  :o so is there any sense in recalculating the results to reflect the lower R/foot leads.  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 23, 2016, 02:43:56 am
Oh wait, are you thinking just normalize the data?  Sure, this makes sense.   

Attached is the drop with 10 Amps through them. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 23, 2016, 02:52:02 am
Here is the data for all of the probes except the Centech at 20 Amps.   That red line at the top is the VICI lead which is marked 20A, where all of the others are marked 10A.   :-DD    I would expect that VICI lead to be the lowest of the group!   

And this is why we run the tests.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 23, 2016, 11:06:45 am
Ohms/inch on right.  Treating the probe as homogeneous, ignoring the probe tip, banana jack, plating, crimps.   

I will normally use a set of the gold Probe Master probes like I tested for general use.  For finer areas, I use the Fluke needles that were on the far right of the bench.  For big stuff, I have the modular type Probe Masters with most of the ends.  A fair investment but comes in handy.   It is also rare I will use a hand held meter to measure current directly.
Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on May 23, 2016, 03:58:08 pm
Those leads catching on fire like that should be completely unacceptable. Smoking and melting is ok, catching on fire is not.

Also, I have a feeling the FLuke leads in china, just like the meters, are made by Uni-T (maybe to slightly better specs than their own stuff).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 23, 2016, 11:57:44 pm
I am not sure.  If you bought a meter that was not fused,  maybe buy a better meter?  If you are in the habit of jumping out your fuses, well some things can't be fixed.   No leads caught fire until they were pushed to destruction.   I'm thinking had I used the test leads tip as a contact at 50A, the tips would have been hot enough to melt the handle.   Keep in mind that the last Fluke probe from the 101 was dissipating over 450Watts when it caught fire!   

They all seem safe enough assuming a fused meter with the correct fuse, except for the Harbor Freight.   The Harbor Freight meter is not fused and even if it were the leads would not handle the 10A.    I ran 5 leads (not shown in the video) with the same results.   
 

Those leads catching on fire like that should be completely unacceptable. Smoking and melting is ok, catching on fire is not.

Also, I have a feeling the FLuke leads in china, just like the meters, are made by Uni-T (maybe to slightly better specs than their own stuff).
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2016, 07:06:54 am
Those leads catching on fire like that should be completely unacceptable. Smoking and melting is ok, catching on fire is not.

I hope you don't work at the health and safety office and are thinking of putting up the price of all out multimeters and making the leads from some horrible plastic.  >:(

This situation is almost impossible in real life. Something else would fail first.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 24, 2016, 04:57:24 pm
This is partly why I ran 5KY's UT61E.  I'm sure the UNI-T owners don't like it but it's good data and the meter was already dead several times over.   Even with the fuse jumped, the PCB could not handle the rated current.   Good leads in the harbor freight meter, measuring the output current of your welder.  That may be the winning real life combo!   

This situation is almost impossible in real life. Something else would fail first.
Title: Re: Handheld meter electrical robustness testing.
Post by: blacksheeplogic on May 26, 2016, 09:01:41 am
Those leads catching on fire like that should be completely unacceptable. Smoking and melting is ok, catching on fire is not.

Thanks to the EU, for the price of a good fused meter you can buy these instead. 10A with an interrupt rating of 20KA. Even with the fuse blown they still work, although, it's a scaled reading. Someone obviously though this was a good idea.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2016, 11:36:19 am
Quote
Fluke provides protection through fusing in its digital multimeters (DMMs), but fused probes provide protection to those who have multimeters that lack the protection designed into Fluke models.

Sure, you picked up a free harbor freight meter with it's non fused 10A input.   

Quote
In addition to meeting entity and organizational requirements for fused test probes, you might also want fused probes because you’re interested in additional levels of protection.

Next you decide to spend over $100 for "additional levels of protection" when you go you check the current the mains provide to your house by looking across them.  :-DD  You blow you fuse/s and can't afford new ones because they cost more than your free meter.   So you jump them out.   

Quote
Voltage readings with a blown fuse are approximate and vary with the meter impedance.

 :-DD

http://en-us.fluke.com/community/fluke-news-plus/safety/new-fluke-accessories-keep-you-prepared-organized-and-safer.html (http://en-us.fluke.com/community/fluke-news-plus/safety/new-fluke-accessories-keep-you-prepared-organized-and-safer.html)

Thanks to the EU, for the price of a good fused meter you can buy these instead. 10A with an interrupt rating of 20KA. Even with the fuse blown they still work, although, it's a scaled reading. Someone obviously though this was a good idea.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 26, 2016, 06:26:02 pm
Those leads catching on fire like that should be completely unacceptable. Smoking and melting is ok, catching on fire is not.

Also, I have a feeling the FLuke leads in china, just like the meters, are made by Uni-T (maybe to slightly better specs than their own stuff).
Pedro, IIRC these probes are required to use flame retardant plastic, not flame resistant.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2016, 12:45:29 am
I was asked about running one of the Probe Master test leads to failure.  Until now, only the old Fluke probe survived to 60A.  The PM probes look like they use some nice cable.   They should for the price!   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2016, 01:07:53 pm
I corrected the OD to add 0.10 to the spreadsheet.   I ran 46" of Belden 0905 8899 002 test lead wire as well.  This is 18 AWG.  For those wanting to make your own test leads, this may be one to consider.     

https://www.youtube.com/watch?v=CqDxMGs_zfg&feature=youtu.be (https://www.youtube.com/watch?v=CqDxMGs_zfg&feature=youtu.be)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2016, 03:14:57 pm
Plots showing the resistance of the probes included with my BM869s compared with the two Probe Master 8017S probes I tested.  The current is being swept from 2 to 20Amps. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2016, 04:23:30 pm
Pictures of the Probe Master 8017S after pushing more than 60A through it.  I cut away the plastic to get a better picture of it.   The expose area of wire appears to be the hot spot.   The wire looks in very good condition.  Also shown are the pin's solder cup and wire tip.  There are no signs of the wire fusing.  It appears to have unsoldered from the heat. 

I wonder if they make these now with lead free solder and how they would differ.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 11, 2016, 03:02:31 am
While waiting for Dave's thick brick meter to be released, I thought I would see if I could find some other brand to try out.   I emailed Gossen just to see if they would respond.  No luck.   :--    I may get one of their low end meters and give that a try like I did with Keysight. 

I came across a company in Korea who exports to the US.  One of their distributors is in Oregon.  They don't have the manual on-line for the meter I want to look at.  Not much in the way of reviews for them.   What's really strange is they seem to make some nice stuff. 

When I first started to look at running these tests, I had a couple of damaged meters.  One was a BK, the other some unbranded cheapo meter I picked up at Sears.  The Sears meter was made in Korea.  You may remember that meter took some major abuse while I was sorting out how much energy it was going to take to run these tests.   

So stay tuned while I blow the dust off the generator.. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 16, 2016, 12:54:26 am
Finally, a meter that is not only designed to survive a 6KV transient but measure it too!    8)
Title: Re: Handheld meter electrical robustness testing.
Post by: gameru on June 17, 2016, 09:04:42 am
Finally, a meter that is not only designed to survive a 6KV transient but measure it too!    8)

We will see a review?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 17, 2016, 02:22:32 pm
I had not thought about it.  I have used the older version of it as well.  The UI is a little different on this new one and I actually like it better.     They are pretty nice if you need this sort of equipment but they come at a price.   This one was around $10,000 US. 

When I was evaluating the original unit,  the HIOKI reps were really good to work with.  I explained what I needed it for and I wanted to run it against the normal CE tests as part of our evaluation process.  They had no problems with this and left the demo unit with me.   Keep in mind, so did other suppliers.   In the end I really liked this particular instrument.   That was maybe eight years ago.   

I would recommend have them bring one in and let let you try it out if you are interested.     There is also a fair amount of documentation on-line. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 19, 2016, 02:03:35 am
Old thread on TPI

https://www.eevblog.com/forum/testgear/multimeter-help/?action=post;last_msg=333115 (https://www.eevblog.com/forum/testgear/multimeter-help/?action=post;last_msg=333115)

TPI actually imports the product from Korea.  The manufacture is Summit.   The meters were UL certified (E188344).  It's also ROHS compliant.  The 194 was replaced with the 194II.   This is a 50K count meter rated for CAT IV 600V and CAT III 1000V.    One thing that sets it apart from any of the meters I have looked at it that it measures inductance.   It also has a tri-display. 

I've had the meter for a few days and it has some short comings.   I wrote TPI to make sure that my concerns were not unfounded.  My plan is do some sort of mini review like I have been, then see how it stacks up against the others..   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on June 19, 2016, 10:31:11 am
Joe, the link should have been:
https://www.eevblog.com/forum/testgear/multimeter-help/ (https://www.eevblog.com/forum/testgear/multimeter-help/)

The 194 you mentioned seems to be very interesting, but the avocado green is really flashy! I wonder if it glows in the dark...  :-DD

Overall the specs are good. I was surprised to see a 50mVDC range, but then the ±10 digits brought me back to reality - it may be suitable mostly for trend analysis (similarly to the 500k count on my BM857). I like how they clearly specify the bandwidth in the AC specs. However, no mention of bargraph update rate (the text actually seems to indicate it is 4Hz).

BTW, nice Hioki meter!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 19, 2016, 12:20:27 pm
It looks like Kawasaki colors....  Very unique.  Think of it as a theft deterrent. 

The manual for the 194II shows for the 50mV range, 1uV resolution, 0.05% +5 counts.   The manual for the 194 shows +/-0.1% or reading, +/- 10 counts.   The older manual shows only the 192 having the inductance mode.   The picture of the 194 shown in that manual seems to back that up.   The newer 194II supports it. 

I was not able to find the newer manual on-line at Summit or TPI.    :--   I contacted TPI and they provided me with a PDF.  I would attach it but the 1M limit strikes again.   

Joe, the link should have been:
https://www.eevblog.com/forum/testgear/multimeter-help/ (https://www.eevblog.com/forum/testgear/multimeter-help/)

The 194 you mentioned seems to be very interesting, but the avocado green is really flashy! I wonder if it glows in the dark...  :-DD

Overall the specs are good. I was surprised to see a 50mVDC range, but then the ±10 digits brought me back to reality - it may be suitable mostly for trend analysis (similarly to the 500k count on my BM857). I like how they clearly specify the bandwidth in the AC specs. However, no mention of bargraph update rate (the text actually seems to indicate it is 4Hz).

BTW, nice Hioki meter!
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on June 19, 2016, 09:56:38 pm
If I understood correctly what you said, the 194I has inductance measurements? That is impressive. The 50mV scale improvement also turns it into a more interesting range. I guess they are able to reach these levels due to a reduced bandwidth.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 19, 2016, 10:24:49 pm
If I understood correctly what you said, the 194I has inductance measurements? That is impressive. The 50mV scale improvement also turns it into a more interesting range. I guess they are able to reach these levels due to a reduced bandwidth.
Yes the 194II has an inductance measurement where the 194 did not.   

I found out about the brand from a friend who had one a few years back.  Apparently it was destroyed when gasoline was spilled on it.  I don't plan to do any chemical tests with this one.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 21, 2016, 10:43:18 pm
I have started working on my review for the TPI194II.  In the mean time,  here is TPI's review of the 194. 

https://www.youtube.com/watch?v=W3lYmqpd5lo (https://www.youtube.com/watch?v=W3lYmqpd5lo)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 22, 2016, 04:42:54 am
Made some good progress with the TPI meter.  I have a couple more tests to run and then pull it apart.   It's looking like I may start the transient testing before the end of the week.   

I wonder if it will at least survive the gas grill ignitor test.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 23, 2016, 12:48:28 am
I would like to find someone who has the TPI 194II.   It appears to have a few software bugs.  I would like to know if they are unique to this one meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2016, 12:17:45 am
I received a response today from TPI about one of the problems I was having with this meter.  You can decide if its a user problem, or a user interface problem.  I have finished with editing and I hope to have Part 1 uploaded shortly.   Because there is not a lot of information about the brand and particular meter, I am going to hold off a few days once I post the video before starting the transient tests.  This will give you an opportunity to review the video and if there is some test you would like to have ran, ask.    Once I start testing, you know how it goes.   Very few meters survive or are repairable.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2016, 03:25:05 am
Here you go, part 1 of my review for the TPI194II made by Summit.   Again, after watching if there is something specific you would like to see done with the meter before it is transient tested, feel free to post it. 
   

https://www.youtube.com/watch?v=fkf0V3Xvq_w (https://www.youtube.com/watch?v=fkf0V3Xvq_w)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 25, 2016, 02:20:25 am
In some of the other videos, I had used an RF generator and small antenna to see how sensitive the meters were to RF.   I forgot to do this with the TPI and will include it with part 2.   

TPI is checking into the scrambled data displayed after logging.  I think I will wait until next week before I start working on part 2 and give them a chance to find the problem. 

Strange that there is not more information about this brand out there.   
Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on June 25, 2016, 03:02:38 am
In some of the other videos, I had used an RF generator and small antenna to see how sensitive the meters were to RF.   I forgot to do this with the TPI and will include it with part 2.   

TPI is checking into the scrambled data displayed after logging.  I think I will wait until next week before I start working on part 2 and give them a chance to find the problem. 

Strange that there is not more information about this brand out there.

The ONLY thing I know about this brand is that they supposedly make meters for Snap-On, like the EDM604AC which should look very familiar to you, and also Bluepoint (Snap-On value brand). I guess now though we know that they are made by Summit. Looking at their lineup they have several that are very clearly Summit meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 25, 2016, 02:17:56 pm
The one my friend had was sold under the Blue-Point brand.   He thought TPI had made the meter.  This is where I first heard about them.   

The ONLY thing I know about this brand is that they supposedly make meters for Snap-On, like the EDM604AC which should look very familiar to you, and also Bluepoint (Snap-On value brand). I guess now though we know that they are made by Summit. Looking at their lineup they have several that are very clearly Summit meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 30, 2016, 12:21:15 am
No word from TPI yet about the scrambled data while logging.   I have been using the meter for normal day to day use and there are a few things worth mentioning.

The orange lettering on the lime green case makes it difficult to read.    It makes this sick sounding last breath death beep when turned off.   If the meter actually put out a decent sound level, It would really be bad.   Maybe this is why the audio is so low.   Turn it off, in the bad of my head I think cheap buggy meter.     This meter smells really bad.  It's been out of the box a week and it smells as bad as it did the first day I pulled it out.   

The meter itself has been working fine.   It still has the original battery.   I plan to give TPI the remainder of the week before I start working on part 2.   It won't be long...





Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2016, 09:39:02 pm
Part 2 of the TPI 194 II

https://www.youtube.com/watch?v=YOyZeiHYA4A (https://www.youtube.com/watch?v=YOyZeiHYA4A)
Title: Re: Handheld meter electrical robustness testing.
Post by: Hydrawerk on July 03, 2016, 11:10:39 pm
Did you damage the DMM with just 270V in the ohms range? This is quite poor result for a CAT IV 600V DMM.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2016, 01:07:42 am
There is a small transformer that I double the line voltage with, then full wave rectify and use this as the input to the meters.  So, yes, pretty much AC applied, rotated the switch and both the resistance  and conductance modes were damaged.   I could see this happening on the bench.   There really is a lack of protection in this meter which is very poor when you consider the price.   

However, the meter did fail safe and I was not injured during the testing, so the protection circuit did it's job.   Well that's what I see posted from time to time anyway.   :-DD   



Did you damage the DMM with just 270V in the ohms range? This is quite poor result for a CAT IV 600V DMM.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 04, 2016, 12:07:51 pm
Joe, I feel bad for you for frying a $250+ meter (almost) beyond repair. Just like unfused current inputs, an unprotected ohms input is below acceptable in 2016...  :(
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2016, 05:21:28 pm
Don't feel too bad for me.   I run these tests to see how well they perform.   I do agree with you 100%.   Having a meter that fails this or that stupid grill starter ESDish test is really bad and is really unacceptable for ANY meter.    But then again, the UT61E remains very popular, so  there are people that really don't care about this stuff.   

I did write TPI to see if I could get a replacement IC through them.  Keeping my fingers crossed that there will be a part 3! 

Joe, I feel bad for you for frying a $250+ meter (almost) beyond repair. Just like unfused current inputs, an unprotected ohms input is below acceptable in 2016...  :(
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 05, 2016, 11:47:52 am
But then again, the UT61E remains very popular, so  there are people that really don't care about this stuff.   

The UT61E has a lot of counts for the price.

The horrible drift, temperature coefficients, etc., mean it's more like 2200 than 22000 in real life but "22000" is what people see.

Plus: The web is full of pictures&videos of people using UT61Es. A lot of people will assume it's a good meter based on that. Popularity breeds popularity.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 05, 2016, 12:42:43 pm
But then again, the UT61E remains very popular, so  there are people that really don't care about this stuff.   
Plus: The web is full of pictures&videos of people using UT61Es. A lot of people will assume it's a good meter based on that. Popularity breeds popularity.

I think there is a fair amount of truth to that. 

I thought about running some temperature tests on the meters that have survived.  I had done this with the UT210E after someone had asked about long term drift.   I think I could cram them all in there....
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 10, 2016, 12:41:06 am
The free Harbor Freight and Innova 3320 meters are back again.  Both of these meters are non functional and have been through several tests.   I saved these as they had one feature I wanted to show off.   The can both measure 10A and are not fused.   

So, how much current does it take to damage a cheap non-fused meter, watch and find out.

https://www.youtube.com/watch?v=-ZQRDoNQr34 (https://www.youtube.com/watch?v=-ZQRDoNQr34)
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on July 10, 2016, 06:09:45 pm
Put them back together, with the leads, and return to Harbour freight. Say you took them out of the pack, and wanted to measure a single AA cell voltage, and this is what happened. Try to keep a straight face as they take the slightly abused part kit out of the package and look at it.

Who knows, if you video using the cellphone camera ( and you are in a single party state so do not need consent) another viral video will result.
Title: Re: Handheld meter electrical robustness testing.
Post by: Maxlor on July 10, 2016, 08:57:07 pm
Sales staff have to deal with exactly that kind of behaviour fairly often (except usually it's meant in earnest.) I doubt they'd appreciate the humor.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 11, 2016, 05:54:53 am
Sales staff have to deal with exactly that kind of behaviour fairly often (except usually it's meant in earnest.) I doubt they'd appreciate the humor.

Yeah, they're probably on minimum wage and work long hours. They certainly won't know the nuances of multimeter safety. No need to go down there and try to make them look bad on camera over a freebie item.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 12, 2016, 08:42:03 am
Put them back together, with the leads, and return to Harbour freight. Say you took them out of the pack, and wanted to measure a single AA cell voltage, and this is what happened. Try to keep a straight face as they take the slightly abused part kit out of the package and look at it.

Who knows, if you video using the cellphone camera ( and you are in a single party state so do not need consent) another viral video will result.

Maybe if I were a child. 

I have yet to turn a meter in for warranty but I may with the TPI.  They responded to my request to obtain a replacement control IC and offered to replace the meter.   I provided them with a link to the second video where the meter was damaged to make sure they understood that this was intentional.  If they are still willing to replace it, I may see if they would care if I attempted the ESD testing on this meter and maybe some of the surge testing on this meter prior to returning it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 16, 2016, 10:59:30 pm
All of the working meters went for a little car ride today. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 16, 2016, 11:03:25 pm
Not a real good test but placed the Fluke DC standard outside the chamber, set for 1 volt.   Meters were held at 40C for 1 hour.  Opened the door to take for some pictures.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 16, 2016, 11:08:29 pm
I used the Brymen as a reference for both sets of meters.   Notice that I had enabled the high res mode for the second set.   

I then took the meters to -10 C and again let them settle for about an hour.   Notice anything strange?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 16, 2016, 11:13:45 pm
The TPI/Summit 194II died.  I tried to cycle it a few times and no luck.  I warmed up the chamber to -5 and it powered up but would read 0V rather than 1.0.   

I took it out of the chamber and let it warm up but noticed I could no longer turn it off.   :-DD

After several minutes it returned to normal.  I could power it on/off and the voltage read the correct values.  Keep in mind that this meter is damaged and a new one may actually perform better.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 16, 2016, 11:22:05 pm
Data I took before opening the door.   They actually did better than I expected.   Besides the TPI not working, the Fluke 101 & 107 had the most drift.  I really thought the two AMPROBEs and the Mastech were going to be the worse of them.

Note too how far out that AMPROBE AM530 is now.  I thought I had tweaked that meter in tighter than that when I repaired it.  Maybe not.  :-// 

Maybe some time I will run the higher res meters with a 1mV and get some more data points.   

Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on July 17, 2016, 01:09:09 am
Nice study, too bad you couldn't test the UT61E in this with its known temp drift issues.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 17, 2016, 10:28:56 am
Joe, good unfused Amp testing (sorry, I am trying to catch up on my video queue)

One detail about the temp testing: I wonder if there was thermal influence in the lead contacts? I am thinking about the interface between different metals, cable resistivity, etc... Despite the voltmeters have a very high input impedance, the differences are in the 10-3 to 10-4 range...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2016, 02:41:06 pm
Nice study, too bad you couldn't test the UT61E in this with its known temp drift issues.

I looked to see if I could find the GS certified 61E for a reasonable price.   

Joe, good unfused Amp testing (sorry, I am trying to catch up on my video queue)

One detail about the temp testing: I wonder if there was thermal influence in the lead contacts? I am thinking about the interface between different metals, cable resistivity, etc... Despite the voltmeters have a very high input impedance, the differences are in the 10-3 to 10-4 range...

Glad you enjoyed the unfused testing.  If I could have found a reputable Amazon supplier of counterfeit large body HRC fuses, I would like to do just a fuse test.   

Yes, there will be an effect from the cables.  Thermal and resistance both.   This is true for inside the meters as well.  A few things to consider, I used the same brand/type of leads through the chain and the thermal effects are going to cancel for the most part.  If we look at the Brymen's location in the first test, we can see it is the second meter in the chain.   In the second test, it is the eighth meter in the chain.  The difference between these two locations in the chain is roughly 80uV.  However, the meter was set to high resolution on test and low during the other.   Actually, its a little worse on the first set where it's the second meter in the chain.    5KY's Fluke 107 has 4mV of error.  This is 18 times worse than the Brymen.  Consider the Fluke was the 4th in the chain in the second batch.

I updated the sheet to show the 5th place data for the Brymen and also included the first data set.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2016, 04:23:13 pm
Fluke paper on various cable effects.

http://www.techni-tool.com/site/ARTICLE_LIBRARY/Fluke%20-%20How%20cables%20and%20connectors%20impact%20measurement%20uncertainty.pdf (http://www.techni-tool.com/site/ARTICLE_LIBRARY/Fluke%20-%20How%20cables%20and%20connectors%20impact%20measurement%20uncertainty.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: Hydrawerk on July 29, 2016, 09:23:01 pm
I wonder why the Fluke 87V failed at tests when exposed to a 1500V pulse. Isn't it UL listed? Was there already a faulty MOV or PTC?
https://www.youtube.com/watch?v=x2Dg1QA71wU (https://www.youtube.com/watch?v=x2Dg1QA71wU)
There seems to be good protection on the PCB of Fluke 87V. I am not sure if Fluke 101 is better designed.
https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/ (https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 30, 2016, 04:21:01 am
I wonder why the Fluke 87V failed at tests when exposed to a 1500V pulse. Isn't it UL listed? Was there already a faulty MOV or PTC?
..
There seems to be good protection on the PCB of Fluke 87V. I am not sure if Fluke 101 is better designed.

Does a meter (any meter) need to be functional in order to pass the IEC standards?  Good protection from a safety perspective or good protection from an ability to survive a transient?

I am not sure what it would take to damage the 101.   The 107 failed at a level about 10X higher than the 87V.   There was another member who ran the 101 on a purchased generator to repeat my tests and indeed it survived.  I was not too surprised as I had added another 1KV and doubled the FWHH of the pulse beyond what the standard called for.   If by better designed, you mean the 101's ability to survive a transient  over the 87V, I don't think there is any question.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 02, 2016, 02:38:16 am
It's been a while I posted about any new meters and longer since anything was good enough to put on the home made generator.   

A few people had asked me about running one low cost meter in particular.  One member offered to send one.  So I have gone ahead and purchased it.  I also picked up a another UNI-T UT61E.  Maybe adding some MOVs will help it at least make it to the surge test.    If it's anything like the UT181A, it will need more than MOVs to get it to survive.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 04, 2016, 04:35:50 am
No updates to the spreadsheet this time.   Just having some fun.

https://www.youtube.com/watch?v=VHZ5cQPGo64 (https://www.youtube.com/watch?v=VHZ5cQPGo64)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 08, 2016, 02:53:51 pm
I have been curious about the GS version of the UT61E since I first read about it.  I was unable to find a distributor that would sell one and ended up getting another standard UT61E.  There have been several posts where people have recommend adding MOVs to the 61E.   

Both 5kY's UT61E and D  failed the grill starter ESD test.  My goal with this next video is to have a look at what effect the MOVs would have on the ESD test and see if I can improve the robustness of this new 61E.

So stay tuned....


 
Title: Re: Handheld meter electrical robustness testing.
Post by: MosherIV on September 09, 2016, 01:38:10 pm
Hi Joeqsmith

I need to put an order in to Farnell (here in the UK) for fuses for my Fluke187. I can get 4 of these
http://uk.farnell.com/epcos/b72210s0381k101/varistor-40-0j-385vac/dp/1004398 (http://uk.farnell.com/epcos/b72210s0381k101/varistor-40-0j-385vac/dp/1004398)

(they are the same as the ones I bought but just from different side of Farnell, I think you call them Element14 in US)
for you to install in the UT61E if you like?

pm my an address I can send them to.

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on September 09, 2016, 04:38:52 pm
I have been curious about the GS version of the UT61E since I first read about it.
GS version?
Title: Re: Handheld meter electrical robustness testing.
Post by: MosherIV on September 09, 2016, 05:32:05 pm
Quote
GS version ?
GS certified. This version is sold in the European markets. As mentiined it has beefed up input protection compared to the Chinese version.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2016, 07:08:24 pm
Anyone interested in a slightly used UT61E?  Appears to have little wear. Includes some spare parts, original box and manual.

A little pre warning.  There will be two parts.  The first video runs about an hour.  I spent a fair amount of time explaining the  what/whys and ran several tests to prove out my results.   Like any problem, there are going to be many solutions.  I touched on only a few. 
   
It's not a good video for the person who just wants some circuit they can copy but I do show everything that is going on including the mods. 

So if you're one of these people who have added MOVs or GDTs to your UT61E or if you have told people this is a smart thing to do, these videos are just for you.   
Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on September 10, 2016, 12:08:39 am
Anyone interested in a slightly used UT61E?  Appears to have little wear. Includes some spare parts, original box and manual.

A little pre warning.  There will be two parts.  The first video runs about an hour.  I spent a fair amount of time explaining the  what/whys and ran several tests to prove out my results.   Like any problem, there are going to be many solutions.  I touched on only a few. 
   
It's not a good video for the person who just wants some circuit they can copy but I do show everything that is going on including the mods. 

So if you're one of these people who have added MOVs or GDTs to your UT61E or if you have told people this is a smart thing to do, these videos are just for you.

Can't wait to see the videos!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 10, 2016, 03:34:08 am
Enjoy.

https://www.youtube.com/watch?v=cMutvk_6xhY (https://www.youtube.com/watch?v=cMutvk_6xhY)
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on September 10, 2016, 01:24:56 pm
Hi Joe
Thanks for the video.
Great work, appreciate the effort you put into this.  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 10, 2016, 02:19:18 pm
Hi Joe
Thanks for the video.
Great work, appreciate the effort you put into this.  :-+

Glad you enjoyed it.  Here is the conclusion.

https://www.youtube.com/watch?v=d6LTsaOqk30 (https://www.youtube.com/watch?v=d6LTsaOqk30)
Title: Re: Handheld meter electrical robustness testing.
Post by: whitevamp on September 10, 2016, 04:53:59 pm
thank's for the vids.
keep up the great vids.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 10, 2016, 06:52:08 pm
Thanks for the video, a good upgrade for the meter, and very good as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on September 10, 2016, 10:50:19 pm
Yes, good work Joe. I am glad that you put in those disclaimers about this making any difference for safety. All the modifications surely made a difference in the survival of the meter but people really still need to understand that this does not make the meter any more suitable for high energy power work. Thanks for the time and money you put into the videos.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 10, 2016, 11:47:05 pm
Yes, good work Joe. I am glad that you put in those disclaimers about this making any difference for safety. All the modifications surely made a difference in the survival of the meter but people really still need to understand that this does not make the meter any more suitable for high energy power work. Thanks for the time and money you put into the videos.

I have never made any claims about safety, only robustness.   I watched several videos on the UT61E before I made these last two.   This included yours. 

https://youtu.be/hhBbvIf3E0s?t=84

I didn't understand most of your comments about it somehow relating to the IEC standards.  The UT513 is an insulation tester and supplies a DC voltage.    My guess is had spark gaps been installed the meter would not have survived.  I am not even sure if you had MOVs in it like the GS meter that it would make it. 

What I don't like about your video is that it leaves people with the idea that the meters can survive 5KV.  If you measured the voltage across the meter when you ran the test, my guess is you had no where near the 5KV claimed.  If you look at the manual for the UT513, the short circuit current is less than 2mA.  The PTC would not even flinch at this.  Novices watching that video may think, hey 5KV, let me hook my Brymen to a 5KV 10KW supply.

Title: Re: Handheld meter electrical robustness testing.
Post by: MosherIV on September 10, 2016, 11:52:09 pm
Thanks Joeqsmith  :-+

Guess just fiting the MOVs does not do much  :(

Always enjoy your videos :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2016, 12:15:00 am
Thanks Joeqsmith  :-+

Guess just fiting the MOVs does not do much  :(

Always enjoy your videos :-+

Glad you enjoyed them. Isn't it better to know why I was concerned.
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on September 11, 2016, 03:09:07 am
Yes, good work Joe. I am glad that you put in those disclaimers about this making any difference for safety. All the modifications surely made a difference in the survival of the meter but people really still need to understand that this does not make the meter any more suitable for high energy power work. Thanks for the time and money you put into the videos.

I have never made any claims about safety, only robustness.   I watched several videos on the UT61E before I made these last two.   This included yours. 

https://youtu.be/hhBbvIf3E0s?t=84

I didn't understand most of your comments about it somehow relating to the IEC standards.  The UT513 is an insulation tester and supplies a DC voltage.    My guess is had spark gaps been installed the meter would not have survived.  I am not even sure if you had MOVs in it like the GS meter that it would make it. 

What I don't like about your video is that it leaves people with the idea that the meters can survive 5KV.  If you measured the voltage across the meter when you ran the test, my guess is you had no where near the 5KV claimed.  If you look at the manual for the UT513, the short circuit current is less than 2mA.  The PTC would not even flinch at this.  Novices watching that video may think, hey 5KV, let me hook my Brymen to a 5KV 10KW supply.

Again we seem to talk past each other. I am agreeing with you, agreeing with your assertions, and never accused you of making any claims to safety. I acknowledge what you say and agree.

My video was never meant to show anything other than the meter did not survive a simple insulation tester voltage. If you ever take the time to read what I have said about meter safety you will know where I stand. My video was a simple experiment and talked about one thing. I never said that a meter that could survive a 5kV test voltage was a safe meter. A meter that is rated at 600V CATIV that can't withstand 5kV at low energy could imply that it does not meet that rating. That was my point and intent.

Your work is appreciated.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2016, 06:05:28 am
The UNI-T UT90A was one of the first meters I purchased to benchmark.   It's been damaged and repaired so many times I call it the cat (because it has nine lives).   So here's for all you UT90A fans.

https://www.youtube.com/watch?v=aRuI_q_K5RY (https://www.youtube.com/watch?v=aRuI_q_K5RY)
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on September 11, 2016, 04:33:08 pm
Van Halen Eruption !!    :-DD :-DD
 ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 12, 2016, 03:58:04 am
Van Halen Eruption !!    :-DD :-DD
 ;D

:-DD I couldn't toss out a meter that could do this! 

With the UT61E now passing some basic transients I thought it needed a backlight to go with all that added protection.   So here's my twist on adding backlight to the UT61E.     

https://www.youtube.com/watch?v=S36LfKmSjKw (https://www.youtube.com/watch?v=S36LfKmSjKw)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 12, 2016, 08:02:18 pm
Van Halen Eruption !!    :-DD :-DD
 ;D

:-DD I could toss out that could do this! 

Wow, even I have a rough time decoding that.    :-DD 

I couldn't toss out a meter that could do this! 

Anyway..... the first meter I ever owned was I think made by Heathkit. It used vacuum tubes and was given to be.   The first new meter my parents bought for me for my birthday.  It was a Micronta capable of reading 50,000 ohm with what they called a range doubler.    I used the meter all of my high school years and repaired / made lots of little projects with it.   I then got my first Fluke (in my 20's)  and it's been digital ever since. 

Today I am going back in time and playing with the first analog meter I have owned since those early years.  This is pretty much the bottom of the barrel for meters but I am finding some things I actually like about it even over my Brymen!   :-DD   

So stay tuned.....
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on September 12, 2016, 08:24:02 pm
How much extra do you think it would cost Uni-T to build the new super meter?

(compared to the existing one)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 12, 2016, 09:09:19 pm
How much extra do you think it would cost Uni-T to build the new super meter?

(compared to the existing one)


I'm have no idea what their engineering costs are, cost to tool a new board, line setup, changing test fixtures, changing procedures, buying parts.....  Are they subsidized, what sort of pricing do they get .... Who knows.  It's not as simple as saying they just sprinkle a few parts in.  I would say your guess is as good as mine.   

I'm not sure what the super meter would even be.  I would start with the UT181A.  I doubt they sell any where near the qty as their low end meters like the 61 and 139 but that's by far the best meter I have seen them offer.   I would gladly pay another $50 for the UT181B that came with a spare battery pack, better materials for the LCD lens (scratch resistant),  more robust case design (I do like the looks of it), meet the EMC standards / more electrically robust,  added AC charger adapters, store the settings in the NVRAM, maybe add the 4-20mA as a percentage.   Just having the meter certified for both standards would be fairly costly.  The rest of what I would like to see is just fluff.  And to be very clear, for them not to try and reduce the bit of quality I am seeing in the 181A I have today! 

Really, I guess what I am suggesting is for them to make an effort to go after that Fluke 289.  The owner of the one I borrowed for that review really liked that UNI-T.  When I told him the price, he was floored.  Then again, could they sell enough to make back their investment? 

If they ever make the 181B, you can bet I will test it again.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on September 12, 2016, 09:17:22 pm
How much extra do you think it would cost Uni-T to build the new super meter?

(compared to the existing one)


I'm have no idea what their engineering costs are, cost to tool a new board, line setup, changing test fixtures, changing procedures, buying parts.....  Are they subsidized, what sort of pricing do they get .... Who knows.  It's not as simple as saying they just sprinkle a few parts in.  I would say your guess is as good as mine.   

We already know they make different versions of their meters.

I'm not sure what the super meter would even be.

I mean the UT61E but with decent protection like the one you built. It has a decent chipset in it, it's a shame you can zap it with simple ESD.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 13, 2016, 12:52:28 am
How much extra do you think it would cost Uni-T to build the new super meter?

(compared to the existing one)


I'm have no idea what their engineering costs are, cost to tool a new board, line setup, changing test fixtures, changing procedures, buying parts.....  Are they subsidized, what sort of pricing do they get .... Who knows.  It's not as simple as saying they just sprinkle a few parts in.  I would say your guess is as good as mine.   

We already know they make different versions of their meters.

I'm not sure what the super meter would even be.

I mean the UT61E but with decent protection like the one you built. It has a decent chipset in it, it's a shame you can zap it with simple ESD.

Not working for them, I really would have no way of knowing what their costs are.  It's too bad that UNI-T does not represent themselves on this site like some of the other companies.  I'm sure several people would have questions/comments for them.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 14, 2016, 12:39:46 am
The Tekpower Sunwa Sannuo Samwa Sunwei or Sanwa clone something or other YX-360TRE-B analog multimeter.  The box for this meter is marked Sunwa. 

Enjoy.

https://www.youtube.com/watch?v=_c7tD7UeXUg (https://www.youtube.com/watch?v=_c7tD7UeXUg)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 15, 2016, 11:02:48 pm
If the Tekpower Sunwa Sannuo Samwa Sunwei or Sanwa clone something or other YX-360TRE-B analog multimeter did not look bad enough already on the inside, I had a go at further improving it's robustness. 

https://www.youtube.com/watch?v=hM2z3GttMkY (https://www.youtube.com/watch?v=hM2z3GttMkY)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 16, 2016, 03:36:58 pm
I have been looking at the manual for the EEVBLOG rebranded BM235.   Even if you don't own the meter, the manual is worth having a look.  Dave gives it his own personal touch.   :-+

Page 1 is a letter from Dave.  A couple of comments that caught my eye:

Quote
It's a beaut little meter, one of the safest and well built meters in a small form factor.
Quote
With the CAT IV rating (exceptional for this size of meter), you can feel confident and safe that you can use this meter on any high energy mains rated equipment in almost any scenario.

Under the general specification, it shows the meter meets EN61326.   Really, it looks pretty good.  What I would expect after running the BM869s.  It looks like they make some nice products.   

There are several nice photos starting on page 27.   It appears there are place holders for several small MOVs, RV1, RV5, RV6 RV7.   There also seems to two extra clamps (Q4,Q5 & Q6,Q7) that are not populated.    Last thing that stands out is it appears PTC1 is a smaller body than PTC2.   I believe any of the PTCs I have seen fail (breakdown) have been a small 5mm type.   I mentioned that when I attempted to harden the UT61E and replaced them.   
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 17, 2016, 06:48:19 pm
Joe, you were wondering why they used 2 sets of batteries for the resistance ranges. The simple reason is that the 9V battery is not ( at least in the regular zinc carbon variety) able to supply 100mA or more, which is needed in the lower resistance ranges to drive the meter to full scale. Using a single ( in your one 2 AA cells so you have enough voltage to drive the LED and the buzzer, otherwise the regular version uses a single cell only)  AA dell will make it able to supply the required current for a long while ( at least long enough to measure 100 or so seconds at a time) without the terminal voltage dropping due to the cell internal resistance rising as it polarises internally with the reaction products. A 9V battery will polarise very fast at 100mA ,in the order of a second or so, but at 1mA or less it will take a long time.

Resistance readings you need to set the zero every time you change range, and do it again after every 100 or so readings as the batteries age and change terminal voltage. However these meters and others of the same type were very common in repair shops decades ago, and served very well to fix almost all equipment that came in. They however are not so useful now, just from the loading the constant current draw ( the ranges DC and AC are basically designed to draw a similar current at FS on each range, so they are pretty heavy loads on modern equipment) is not something you have to consider with a modern meter with a relatively constant high input impedance.

As to the AC range, those meters almost invariable are calibrated to read an average voltage with half wave rectified AC, but are calibrated so the scale reads RMS voltage instead. Thus on AC with DC applied they read high by around 30%, but for the use of checking transformer AC voltages this is fine. As well the AC voltage ranges are non linear at the bottom end, simply because they tend in modern meters to use a silicon diode, as opposed to the original use of a germanium point contact diode, with it's lower forward voltage drop. Basically AC voltage below 20% of full scale will be inaccurate, but that was often pointed out in the older manuals.

As to those extra diodes you added, very nice, I should add them to my old Hioki meter, as I have burnt a few resistors, funny enough pretty much those you cooked ;) in the years I have had it. Was new in around 1980 when I got it as a birthday present. Still use it as well.

You were wondering how they damp the meter movement from damaging itself, which is done using the aluminium former that the movement coil is wound on. This forms a shorted loop in the meter magnetic field, and thus provides a frictionless damping for the meter needle,  damping fast acceleration by being both an eddy current damper in the magnetic field of the magnet to fast angular acceleration of the needle, and also being a shorted turn in the transformer formed from the coil and conductive frame so reducing the effect AC current has on the meter movement. However the pivot mountings are the weak point, dropping the meter often either breaks the pivot off of the coil as the drop of shellac holding the pin there breaks, or it bends the pin and adds a massive friction load with the bent pin, or simply moves the coil into contact with the frame, or out of the linear portion of the gap field making the response less linear than it was.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 17, 2016, 07:56:56 pm
You were wondering how they damp the meter movement from damaging itself, which is done using the aluminium former that the movement coil is wound on. This forms a shorted loop in the meter magnetic field, and thus provides a frictionless damping for the meter needle,  damping fast acceleration by being both an eddy current damper in the magnetic field of the magnet to fast angular acceleration of the needle, and also being a shorted turn in the transformer formed from the coil and conductive frame so reducing the effect AC current has on the meter movement. However the pivot mountings are the weak point, dropping the meter often either breaks the pivot off of the coil as the drop of shellac holding the pin there breaks, or it bends the pin and adds a massive friction load with the bent pin, or simply moves the coil into contact with the frame, or out of the linear portion of the gap field making the response less linear than it was.

This is interesting. When I was searching old meter manuals, this never came up. I assumed this is what the small cap in parallel with the works was for.   Are you suggesting this technique was used for this particular meter?
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 17, 2016, 08:07:07 pm
Joe, movement dampening was used widely in AVO's, they had a 2 rotary dial UI and the movement is well dampened when the dial AC was in the Off position and the DC dial in the DC position.
Yeah sounds silly I know but it's well documented in the manuals and even on the meter backplate as for "Transit".
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 17, 2016, 08:17:53 pm
Very common on all d'Arsenoval movements as this method of damping is both very effective and very low cost to add to the meter during manufacture, plus it does not affect accuracy in any way at all in use.

You could get some very sensitive fast response movements which did not use the shorted eddy current turn, instead using a insulating slot on the former to make it undamped, and these were used mostly as mirror galvonometers in equipment like scanners, where they wound the movement to a higher current ( using a thicker wire) plus using a crossed coil to make the deflection depend on the current rather than force against a spring. Done more to get a good transient response so you could do XY scanning with 2 sets of coils orthogonal to each other, to drive a display very fast with some semblance of positioning accuracy. Damping on those was mostly by using a vane on the movement in the air to keep overshoot within limits, but they would still have a little oscillation around the balance point for step changes in coil current.

Putting the meter in DC current range for transit was also used on those meters with no dedicated position, the AVO had those 2 switch positions which meant the meter movement was shorted along with the eddy current winding, to provide extra damping of the needle during transit.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 17, 2016, 09:08:48 pm
Even with the cheapest of analog meters, we still have an opportunity to learn something.  :-+   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 19, 2016, 01:26:30 pm
The EEVBLOG rebranded Brymen BM235. 

Also, I have updated the spreadsheet to include the BM235.

https://www.youtube.com/watch?v=g3uYcHAumhA (https://www.youtube.com/watch?v=g3uYcHAumhA)
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on September 19, 2016, 02:52:31 pm
Nice review Joe.
This is the best review yet of the BM235, IMHO
I especially liked the reverse engineering of the input protection circuitry.
I also liked the comparisons with the other meters.
Thanks for the time and effort you put into your videos.

3DB  ;D
 
Title: Re: Handheld meter electrical robustness testing.
Post by: whitevamp on September 19, 2016, 07:32:03 pm
nice review/testing oi the bm235
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 19, 2016, 08:20:27 pm
Joe, around 8 minutes in you show the pillar that's been modded to clear the PCB.
There were a couple of cracked inductors and Dave did a vid on the fault:
https://www.eevblog.com/forum/blog/eevblog-884-eevblog-bm235-multimeter-repair/ (https://www.eevblog.com/forum/blog/eevblog-884-eevblog-bm235-multimeter-repair/)
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on September 19, 2016, 11:33:20 pm
Hi tautech, after Joe showed the modification that Brymen had apparently done to the case mating sleeve by removing material I pulled my meter back apart to check and inserted a sliver of aluminium foil which is around 10 microns in thickness over the top of L3 and then put the meter back together and cranked up the screws with the batteries out just in case, after re-inspection there was no evidence on the foil that the sleeve was making contact with L3 on my particular meter.

As you mentioned after a recent component issue in that area perhaps Brymen felt that the clearance was insufficient thus their modification. My meter was one of the first sold and the case mating sleeve is intact and not modified as Joe’s appears to be.
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on September 20, 2016, 12:09:19 am
Nice review on the BM235 Joe. I am getting a little pissed off with Brymen though. the BM235 seems to have had a few small problems and then this quality control problem with the test lead jacks?

Except for that problem, the BM235 looks to be a great addition to the Brymen family. They certainly take safety seriously.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 20, 2016, 03:43:11 am
Nice review Joe.
This is the best review yet of the BM235, IMHO
I especially liked the reverse engineering of the input protection circuitry.
I also liked the comparisons with the other meters.
Thanks for the time and effort you put into your videos.

3DB  ;D

Thanks!  As usual, when I went back and watched it there are a few things I wish I would have changed.  For example, I frequently use the nS mode of the BM869s and never even mentioned it.  I also made a big deal of the UT61E being able to accurately measure 100Mohms but never brought it up.  Never mentioned the cost of the HIOKI......  Glad you are enjoying them. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 20, 2016, 04:27:13 am
Hi tautech, after Joe showed the modification that Brymen had apparently done to the case mating sleeve by removing material I pulled my meter back apart to check and inserted a sliver of aluminium foil which is around 10 microns in thickness over the top of L3 and then put the meter back together and cranked up the screws with the batteries out just in case, after re-inspection there was no evidence on the foil that the sleeve was making contact with L3 on my particular meter.

As you mentioned after a recent component issue in that area perhaps Brymen felt that the clearance was insufficient thus their modification. My meter was one of the first sold and the case mating sleeve is intact and not modified as Joe’s appears to be.

Looking at the main half of the case (with the display) measuring the height of the lower lip to the upper lip, I get 0.165".  From the upper lip to the top of the boss measures 0.165".  From the top of the boss to the top of the PCB measures 0.412".     So, the lower lip to the top of the pcb is 0.412-2(.165)  or 0.082".    When the back case is installed (which has the batteries), the lower lips fits tight against the lower lip of the main case.  The mating boss on the back case is flush with the upper lip.   Measuring from the back case lower lip to the upper lip I measure 0.082".   So, the idea is that the back cases boss actually rests against the top side of the PCB.   

I would normally put some clay in there to measure it (or I like the dental stuff) but is seems that I can view the boss looking through the large fuse holder.  I attempted to get a picture of it but that's a real SOB to get in there with my camera and a light.  Attached are a couple of pictures showing the zero clearance.  That boss would touch off on L3.  You can see they were hand soldered.  I suspect they had some returns and thought it was a bad fillet, so add more solder and missed it was a clearance problem.  Good question for Brymen.  I'm fine with their short term fix. 

Also shown are two of the pictures I took showing the how the connector was not soldered flush to the PCB causing the offset in the bore.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on September 20, 2016, 05:37:32 am
I just had another look at mine and the female boss/ mating sleeve is making contact with the main PCB as you suggested but saturating the sleeve end with an engineering marker did not leave any recognisable imprint, the mating boss on the rear of my meter only just clears L3 laterally and it wouldn't take much to have it make contact and potentially have side pressure applied once the case was reassembled.

Excellent work and many thanks.   :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 20, 2016, 05:47:09 am
Good point!  I had not thought of that.  So the outside boss actually fits down beside L3. Does look like there could be enough clearance.   Wow, one wrong drop and there could be a fair amount of side loading as you suggest in that little bead.
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on September 20, 2016, 04:49:46 pm
I passed on the link for the video to Brymen. They said "As the poor installation of the input jack assemblies, I have informed our production to pay attention to it and improve it. Thanks for feeding back it to us. "
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 20, 2016, 11:43:17 pm
With YouTube, one metric they provide is what external sites view your content.  You would think being such a small fish in the world of on-line videos, no one would care.  Yet some fairly large distributors and meter manufactures seem to visit from time to time. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on September 21, 2016, 08:24:42 am
The EEVBLOG rebranded Brymen BM235. 

Brymen definitely seem to have some quality control issues there.

Misaligned posts (you'd assume the posts would be held in a jig while they were being soldered but apparently not), interference problems between the case+PCB. Dave has already done a couple of videos on fixing electrical problems from poorly chosen components (whining capacitor, LCD contrast).

It just shows how difficult it is to get everything right in production.
Title: Re: Handheld meter electrical robustness testing.
Post by: spronkey on September 21, 2016, 08:55:13 am
I passed on the link for the video to Brymen. They said "As the poor installation of the input jack assemblies, I have informed our production to pay attention to it and improve it. Thanks for feeding back it to us. "

Maybe the one Joe got was last off the production line on Friday :) I find it amusing that a company like Uni-T seems to have no trouble with quality of production, despite the shortcomings in design, yet Brymen seems to struggle a bit.

Just wanted to add thanks for all your work testing these meters Joe, really interesting to watch and learning a lot. Also great when looking to purchase some of these meters - especially the ESD type tests.

How much will the transient tests be wearing out the MOVs on these meters? It'd be interesting to see a test on a meter where the MOVs have worn out, and to see whether it changes the way the meter responds to transients.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 21, 2016, 01:41:06 pm
Just wanted to add thanks for all your work testing these meters Joe, really interesting to watch and learning a lot. Also great when looking to purchase some of these meters - especially the ESD type tests.

How much will the transient tests be wearing out the MOVs on these meters? It'd be interesting to see a test on a meter where the MOVs have worn out, and to see whether it changes the way the meter responds to transients.

No problem. Glad to share the little bit I have done.  I learn something from each meter I look at and some of them still impress me.  There was no way I would have thought that the BM235 would survive at these levels.  I know the fan boys (Fluke 87V, UNI-T, etc)  hate seeing their meters so low in the standings and will deny it, suggest the test is bad, suggest I had it in for their meter...  It's pretty funny really that people can be so attached to their meters.  I just run the tests and present the data.   

About MOVs wearing out, it's a good question and I don't think it's something I can answer.  The MOVs will be rated for some level, some number of hits at some standard.  These are normally a direct hit.  Now you put a PTC and maybe a resistor in front of it...   I have some experience with them being damaged in real life, catching fire, splitting, etc.

Let's consider the EEVBLOG rebranded BM235.   I tested five of the function selections (LoZ, V, ohms, mV and diode).  I then ran eleven different levels (1KV, 1.5, 2, 2.5, 3, 4, 5, 5.8ish, 6, 8 and 10KV).   Each function is tested with five transients at each level in both positive and negative polarity.  So 5 * 11 * 5 * 2 or 550 transients total!
But they are not at the same energy levels....    Again, the MOVs are normally taking a direct hit, with a very low impedance source.   The small MOV in the BM235 is rated
for 40J with the 8/20us.   But in the meter, we have a 1.5K PTC and a 1K resistor limiting the current into the device.  We can pretty much ignore the 2ohm source of the generator.   Even if the MOV was taking a direct hit from my generators, I test with under 20J.  Most meters were damaged with less than 10J available! 

So, where does that leave us.  What I can tell you is that I have yet to see an MOV fail as part of my testing.  What fails are the PTCs, input resistors, high speed clamps, ICs, PCB traces.

Consider the Fluke 107 that 5KY's sent me.  That meter has seen the worst of any meter I have tested.   You would really have to be stupid and hook it to a MOT or something to damage it.  15KV 100us FWHH to damage it!  And what failed, not the MOVs.  The high speed clamps and the PCB.     
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 25, 2016, 05:27:53 am
MOV units degrade slowly. The energy rating is not an indication of life, just how much they can take in a single shot. I have had them connected across the mains, and find that the large or small ones fail only after over 5 years of being abused, generally by going either low resistance, and thus blowing apart, or going dead short and either vaporising the one lead or turning into a skid mark on the mounting and a powder all over the inside of the equipment. Nice failure mode, generally takes out the fuse or breaker doing so.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on September 25, 2016, 06:45:38 am
Just on the subject of MOVs, I was recently called out by a client to check and rectify their existing security system which I had installed years earlier, the premises have been hit twice by direct lightning strikes destroying everything in the past but this time it appears to be a transient or surge up the phone line, Telstra did attend to the site and confirmed that they do have a line surge device on the line at the entry point but obviously something got past it. Here is a picture below of the damaged MOV measuring 26 ohms in situ, the other two appear ok and are each around 17 megohms.

The rest of the existing control panel was in good order and operational apart from failing to communicate so I simply replaced the main PCB with a new one as I didn’t want any further issues, the site was 500 kms round trip so I stayed for a few days and did some other maintenance around the place to make it a worth while journey, we also ate rabbit for a week. 
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 25, 2016, 08:35:28 am
Just on the subject of MOVs, I was recently called out by a client to check and rectify their existing security system which I had installed years earlier, the premises have been hit twice by direct lightning strikes destroying everything in the past but this time it appears to be a transient or surge up the phone line, Telstra did attend to the site and confirmed that they do have a line surge device on the line at the entry point but obviously something got past it. Here is a picture below of the damaged MOV measuring 26 ohms in situ, the other two appear ok and are each around 17 megohms.

The rest of the existing control panel was in good order and operational apart from failing to communicate so I simply replaced the main PCB with a new one as I didn’t want any further issues, the site was 500 kms round trip so I stayed for a few days and did some other maintenance around the place to make it a worth while journey, we also ate rabbit for a week.

Just how does the response time SLA work there, 500km is going to eat badly into the 5 minute response time for an alarm activation.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on September 25, 2016, 09:04:17 am
Hi Sean, the system just reports via SMS message to the clients mobile over PSTN for mains outages, alarm/ fire events and also notifies of low water tank levels in which case we can remotely pump water up to the header tanks from either the dams or the bore, on an event he can readily contact neighbours who will rapidly attend to check things out in addition to remote camera surveillance, all pretty nifty stuff but mobile phone coverage in that particular remote location is ordinary at best and the latency of his satellite internet connection makes it a bit tricky to do stuff in real time reliably.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 25, 2016, 12:25:54 pm
MOV units degrade slowly.
Not always the case. 

The energy rating is not an indication of life, just how much they can take in a single shot.
I don't think anyone made this claim.  However if I put 10J into a 1J part or a 100J part, which do you think will survive longer?  This is a question of derate and it's not something simple that could be answered.    OP's question was  "How much will the transient tests be wearing out the MOVs on these meters?" and my claim again is that I have yet to see a MOV fail during my testing.  And I would go so far as to say if I took for example the EEVBLOG rebranded Brymen BM235 and attempted to run a test using my transient generator, I could not get MOVs to fail.  The generator is just not capable and the PTC with the added resistor will really go a long way to prevent any sort of overheating in the MOV. 

If you are interested in reading a little on MOV's MTBF, Kenneth Brown published a fairly basic article several years back.   Again, how you would model it, not so simple.   
http://iaeimagazine.org/magazine/2004/03/16/metal-oxide-varistor-degradation/ (http://iaeimagazine.org/magazine/2004/03/16/metal-oxide-varistor-degradation/)
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on September 25, 2016, 02:52:38 pm
Yes, on a historical note, it tooks decades before MOV makers put in-lines fuses with MOV [ you can still get them without it], as when they finally fail they fail catastrophically; although a 'used' one can be taken out of service by testing its pass through voltage, that's practically impossible once imbedded in devices. 

In good DMM designs the casing holds in the debris and fire, but in prior years particularly in surge strips when higher joules were all the rage, the high joule capacity MOV would burn with enough energy to eat through the strip housing; in the past, the solution of the designers was too use a metal container  :-//.  A simple in line fuse or better yet in-line and a thermally activated one as double fail safe, saves the day.

(http://mediaweb.kirotv.com/photo/2012/05/17/Surge-Protector_4037022_ver1.0_1280_720.jpg)

MOV units degrade slowly. The energy rating is not an indication of life, just how much they can take in a single shot. I have had them connected across the mains, and find that the large or small ones fail only after over 5 years of being abused, generally by going either low resistance, and thus blowing apart, or going dead short and either vaporising the one lead or turning into a skid mark on the mounting and a powder all over the inside of the equipment. Nice failure mode, generally takes out the fuse or breaker doing so.
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on September 25, 2016, 02:54:40 pm
Muttley just on the off chance, do you know what part number of MOV that is or do you know if a fuse is inline with it?  It failed fairly gently so I'm presuming it has an in line fuse.

Just on the subject of MOVs, I was recently called out by a client to check and rectify their existing security system which I had installed years earlier, the premises have been hit twice by direct lightning strikes destroying everything in the past but this time it appears to be a transient or surge up the phone line, Telstra did attend to the site and confirmed that they do have a line surge device on the line at the entry point but obviously something got past it. Here is a picture below of the damaged MOV measuring 26 ohms in situ, the other two appear ok and are each around 17 megohms.

The rest of the existing control panel was in good order and operational apart from failing to communicate so I simply replaced the main PCB with a new one as I didn’t want any further issues, the site was 500 kms round trip so I stayed for a few days and did some other maintenance around the place to make it a worth while journey, we also ate rabbit for a week. 

Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 25, 2016, 03:16:50 pm
Well, the MOV's on Mutley's boards are on a phone line, so the typical value for these is 250VAC rating, and generally there is also a upstream dual spark arrestor, typically a 470VAC device. Limited energy on a phone line, you will find the few kilometres of fuse wire, otherwise known as the twisted pair cable, are a very effective energy limiter to reduce the power into the board.

However most of the time the board fails from having an inadequate ground connection, as typically the installers either use the mains wiring, with a 0.75mm earthing conductor, which is very inductive as it is typically quite long and only connected to a poor local grounding system. Ideally you need a 4mm cable (minimum) direct to a good ground rod array, directly into the ground and with minimum length, with the telco side spark gap connected there as well.

Attached is an old failed electric fence load unit, which has to absorb the 4J of power in each pulse from the energiser, and which typically gets a belt every second. The VDR elements there rarely fail, unless hit by lightning, and the typical failure is the high voltage transformer suffering from insulation breakdown. 6 1kV MOV units in series, and the IR led is the touch detector, measuring the voltage pulse on each cycle and communicating it as a light intensity pulse to a remote phototransistor on the main board. Cheap way to get a 20kV optoisolator.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 25, 2016, 03:24:11 pm
Most applications, like line cords, the MOVs will be directly across the source.  I doubt that would ever be allowed in a hand held meter (certified).  There was one meter I looked at that had the footprint for a MOV right across the input.   :palm:  It was a not populated.   Every meter I have looked at has something to limit the current to the MOV (combination of resistors and PTCs).   Then the MOVs are always clamping above the rating of the meter.  Even if one were to short, we have a second device in play to keep the MOV from coming apart (or catching fire, etc). 

The meters on nice high impedance devices (except for the current inputs) so they can get away with the PTCs / resistors.   Tough to add a few Kohms in line with your AC outlet and have it still be useful.   :-DD      As mentioned, a fuse or CB is an option.   

There was a pretty good article I read once about the marketing side of line cord surge protectors.   Marketing kept pushing for lower clamping voltages as a sales pitch.   Of course, this led to all sorts of problems.  Pretty funny really.  Again, nothing to do with hand held meters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on September 25, 2016, 11:59:28 pm
Muttley just on the off chance, do you know what part number of MOV that is or do you know if a fuse is inline with it?  It failed fairly gently so I'm presuming it has an in line fuse.

Greetings Saturation, there are no fuses that I am aware of in line with the phone connection on any security system that I ever worked on or installed and I have done quite a few, all three of the MOVs are 14D471K and the relay for the mode 3 is still working and tested as good, I just had a look at the earlier original iteration of this series (Bosch Solution 16) and they also used similar MOVs, this was the first time I had seen this occur on any panel.

Anyway the reason for the post was just to point out that large transients can be present on systems and equipment that most of us take for granted, the next time I hear a thunderstorm on the other side of the hill instead of fitting off equipment particularly phone related I will instead go to the fridge and sit it out.

Data sheet and picture below.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 28, 2016, 06:02:48 pm
Tested a cheap meter on 7500V neon sign transformer. it survived .....for a while at least.

https://www.youtube.com/watch?v=wN6zXposTV4 (https://www.youtube.com/watch?v=wN6zXposTV4)

Then I went a little Photonic on it, and cooked it to death.

https://www.youtube.com/watch?v=VXOQGJ2UjY8 (https://www.youtube.com/watch?v=VXOQGJ2UjY8)

Battery expired in 2011, but still has life in it ( Yay Energiser) so put it in another cheap meter to eke the last life out of it ( Ok, I am out of 9V batteries, and only going to buy more later the month if I can get past the one shop with them pretty cheap).

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 28, 2016, 10:17:17 pm
Sean, that's not a neon sign transformer... This is a neon sign transformer!!  :-DD :-DD

https://youtu.be/RBkjr3b5hQo?t=379
Title: Re: Handheld meter electrical robustness testing.
Post by: PedroDaGr8 on September 28, 2016, 11:04:29 pm
You should rename your channel on YouTube to MeterAbuse. :-BROKE
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on September 29, 2016, 11:33:44 am
Tested a cheap meter on 7500V neon sign transformer. it survived .....for a while at least.

Then I went a little Photonic on it, and cooked it to death.

Battery expired in 2011, but still has life in it ( Yay Energiser) so put it in another cheap meter to eke the last life out of it ( Ok, I am out of 9V batteries, and only going to buy more later the month if I can get past the one shop with them pretty cheap).
Sean, I don't think you were going Photonic on your last video. To me you were simply using a non-orthodox method of reflow soldering to bring it back to life. Sure, a few cooked plastics here and there, but that happened even with Dave and his attempts to restore a TV in one of his episodes.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 07, 2016, 03:24:28 am
Some time ago someone had offered to give me a pen type Mastech MS8211.  Another person had asked about running one.   Fairly inexpensive so I picked up a MS8211D.  It's marked CAT III 600V, has some sort of current, a funky retractable tip and a strange logic sort of LED indicator.   I have not had it apart yet but I wonder if it even uses a fuse as t looks like it can only read into the mAs.   

Hope to have some time in the next week or so to do something with it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 11, 2016, 12:51:12 am
Some time ago someone had offered to give me a pen type Mastech MS8211.  Another person had asked about running one.   Fairly inexpensive so I picked up a MS8211D.  It's marked CAT III 600V, has some sort of current, a funky retractable tip and a strange logic sort of LED indicator.   I have not had it apart yet but I wonder if it even uses a fuse as t looks like it can only read into the mAs.   

Hope to have some time in the next week or so to do something with it.
Joe, that was me, although mine is safer as it does not do current measurements. I have hi res pictures of its guts if you are interested (I am away from my computer now)

Keep in mind the retractable mechanism is flimsy and the thread on the tip started to miss steps until the point of not pushing it out anymore.

Otherwise, it is an interesting form factor.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 11, 2016, 02:43:31 am
You must be the one who offered to send the defective one.   I had a few people write me about it.  Not sure why it would be popular.  The first thing I noticed was how poor that retractable tip was constructed.  I hope to have a some time this week to run it.

If there is anything you want to see with it while it is still in working order, let me know.   
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on October 11, 2016, 06:16:30 pm
Sean, that's not a neon sign transformer... This is a neon sign transformer!!  :-DD :-DD

https://youtu.be/RBkjr3b5hQo?t=379

I said it was the baby neon sign transformer, the other 14kV ones are at home, where they can make a really respectable snap crackle and pop. They also deliver 30mA, and the one electronic one is running my neon collection.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on October 12, 2016, 11:17:31 pm
Hi Joe, If you haven't already blown up the Mastech 8211 can you verify the maximum current it will cope with in regards to current draw, the manual states 200mA and I've been looking at these things for years but the two main concerns were current limitations and a lack of a backlight.   :-+

Also Mastech's web site appears to have recently expired, shorted out, blown a fuse or something.    :-BROKE :palm: :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 12, 2016, 11:52:12 pm
Hi Joe, If you haven't already blown up the Mastech 8211 can you verify the maximum current it will cope with in regards to current draw, the manual states 200mA and I've been looking at these things for years but the two main concerns were current limitations and a lack of a backlight.   :-+

Also Mastech's web site appears to have recently expired, shorted out, blown a fuse or something.    :-BROKE :palm: :-DD

You are in luck!  I have not yet done anything with it.  You want to know what is the maximum current it can measure for both DC and AC?  The manual does show 200mA with a 100uA res.  The max display is listed at 1999, so I would assume 199.9mA.  The manual does mention the resettable fuse.  They also show a frequency range of 40-200Hz.   

Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on October 13, 2016, 12:05:17 am
Thanks Joe,   :-+

For my needs just DC is fine, I carry a couple of larger meters in the truck anyway and was only looking at these things after having a short play with one a while back, I thought that for around thirty bucks one could live permanently in the tool box, some devices we test pull around 150-180 mA but occasionally they can draw slightly more, many thanks.   :)
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on October 22, 2016, 11:29:23 pm
Haven't seen Joe about the place in a while, hope he is ok and the Mastech didn't get the better of him.   :scared:

He is also about to hit 1000 subscribers so a big thank you and congratulations are probably in order, Thank you Joe and well done.   :-+

Joe's Videos.
https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg/videos (https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg/videos)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 23, 2016, 01:46:11 am
Haven't seen Joe about the place in a while, hope he is ok and the Mastech didn't get the better of him.   :scared:

He is also about to hit 1000 subscribers so a big thank you and congratulations are probably in order, Thank you Joe and well done.   :-+

Joe's Videos.
https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg/videos (https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg/videos)

I have moved the spreadsheet to GoogleDocs.   The latest may be found here.   

https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit#gid=400910915 (https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit#gid=400910915)

I would say I got the better of the Mastech MS8211D.   Not real impressed with the design or quality.   
https://www.youtube.com/watch?v=0vwGgdmdbyI (https://www.youtube.com/watch?v=0vwGgdmdbyI)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 23, 2016, 01:09:34 pm
From youtube
Quote
I'm surprised you had all the features and were able to function test this unit with that wire and solder blob.

Note that the two diodes in question are shorted so the solder bridge would have no effect if it stayed in place.   Also the clipped lead is not making contact with anything.  It was held in place with the insulating tape that was used to prevent the crystal from shorting against the IC's pads.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 24, 2016, 10:42:30 pm
A message body...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 30, 2016, 04:47:41 pm
Sitting here is a new in the box AIMO MS8211. It's marked 600V CAT III and is similar to the MS8211D in that it's a pen type as well.   It has a back light, non-contact voltage detector and even a little flash light in the tip.   It does not have the logic probe like the D model.   Unlike the D model, they also use a mechanical 250mA fuse rather than the PTC to protect the current input.  They claim the diode test is 1mA at 2.8V.  This would also be a step up from the D model.   

Keep in mind, like the D I doubt it will hold up to the testing well.  Again, these pen probes just seem like a bad idea.

As usual, if there is any specific test you would like to see ran feel free to ask.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on October 30, 2016, 06:38:37 pm
How about doing the high voltage testing one time with the bare board in the case, with a mirror ( well insulated) so we can see both sides of the board at the same time to show where the arc over occurs.  Need to have the cover on for this, and latch it down well for your own safety, as it will make copper vapour as it blows.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 30, 2016, 07:50:44 pm
The mirror is an interesting idea.  Cheaper than a second camera!  :-DD

I don't talk about safety much when I run these tests.  The energy levels are normally so low, there is very little risk.  The generator has a fair amount of safety features designed in as well.  The half cycle generator adds a little more risk.  The cameras are about two and a half feet back to avoid any damage to them.  I am no where near the device I am testing when they go off.    I keep the output shorted up until I am ready to run the test.  If I test with fuses, light bulbs or other things with glass I will normally cover them up to at least contain the fragments.  Once the transient has fired, I shut the system down and short the outputs before doing anything else.  Running an open board would pose less of a risk than having something that can contain the pressure, like my fuse powered rocket.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 07, 2016, 02:48:24 am
Some things just never get old.....    Video is finished with some bonus material.  About a half hour total. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 07, 2016, 02:54:40 pm
Joe just recently posted another video on his Youtube channel so here it is linked below.   :-+

https://www.youtube.com/watch?v=f-wLD1JwU5Q (https://www.youtube.com/watch?v=f-wLD1JwU5Q)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 08, 2016, 01:26:36 am
Sad to see the pen meter fail with the 220V line test but on the plus side at least it survived the grill starter unlike the vast majority of UNI-T meters I have looked at. 

We will see what Fluke has to say about the VHS tape.   

In the mean time, I have a little nicer analog meter I plan to look at next.  It's a Ketai Instruments KT-7050 sold under the Tekpower brand.  I may see if the schematics are available and just see if I can made it more robust rather than just damaging it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joseph nicholas on November 08, 2016, 01:45:01 am
My cheap meter stopped working after only 9 months on all its voltage scales. I decided to buy a MF-47 analogue miltimeter kit.  At least if it gets damaged I know it would be easy to fix if needed from handy through hole parts.  It will probably be my go to meter of choice for trouble shooting.  I was inspired to do this after seeing the abismal quality of construct of the digital I bought.  The circuit board looked like it was stored in a wet basement for several years.  It was corroded and mouldy.  I bought it as new.  When I viewed the you tube video of a teardown of the same meter the internals were nothing like the video showed.  The exteriors were exactly the same.  When I got the meter the  a wire fell out of one of the probes for no reason.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on November 10, 2016, 11:51:40 am
@Joeqsmith
Take a bite out of UNI-T  :-DD :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joseph nicholas on November 10, 2016, 01:41:37 pm
I found mine on ebay.  I haven't gotten the kit yet to assemble but I'll tell you how it goes.  This is perhaps the uglyest multi-meter ever made but it has a bale, and what could be some decent test leads for a change.  I paid something like 10.00usd for it but after I paid the site raised the price so go figure.  While I am waiting for the analog meter I tried to fix the cheapy.  It too has some schematics on line but unfortunatly no joy.  I doubt I cooked the chip because the thing still counts and works in the other modes.  Eventually I know I will fix it and it too should last. 

jnicholas
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2016, 04:24:40 am
This is perhaps the uglyest multi-meter ever made but it has a bale, and what could be some decent test leads for a change.
jnicholas

 :-DD  It looks cleaner than that first analog meter I tore apart.  If that wasn't ugly enough, I really made a mess of it with all my mods.   :-DD
Looking forward to seeing the kit. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 11, 2016, 04:33:05 pm
Joe, that was a pretty cool mushroom in the high speed camera.
Despite it is stronger than your UNI-Ts, I can't help but imagine this is actually much more unsafe than a DMM on the table: the potential to burn the hand that holds the pen while this happens is pretty high.

Anyways, that was another excellent video! Thanks for doing this.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 12, 2016, 02:02:11 am
Joe, that was a pretty cool mushroom in the high speed camera.
Despite it is stronger than your UNI-Ts, I can't help but imagine this is actually much more unsafe than a DMM on the table: the potential to burn the hand that holds the pen while this happens is pretty high.

Anyways, that was another excellent video! Thanks for doing this.

Thanks for the compliment.   I do like that camera.  It captures things that we just don't see with the slower one. 

I get what you are suggesting about how this meter could be less safe than the UNI-T's even though it held up a little better.  Keep in mind, while the grill starter did not end it's life, that little rectified AC waveform did.  IMO, its a pretty poor design.  We can look at the mushroom cloud and think it's worse but I really don't know.  The energy is just so low I am really not sure what it tells us.  If we ran fuse tests on every meter using an actual CAT III line, what would actually happen?  Meters we think look safer may indeed come apart with some a much more dramatic effect.   I just don't know.   We need to leave safety to the experts. 

When I made those couple of videos showing how stupid it is to jumper out an HRC fuse, at one point I stuck in some 28 AWG or something of that sort.  When I hit it with my generator, I did not even have enough energy to blow that wire.  It's pretty pathetic relative to photonicinduction's sort of destruction.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 12, 2016, 03:05:48 am
Well, my reason to assume the relative safety levels is based on the distance between the operator's body and the source of the explosion...

However, there's always a chance the dial of the meter on the table comes flying after the event and hits the operator in the head...  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 12, 2016, 04:41:21 am
Well, my reason to assume the relative safety levels is based on the distance between the operator's body and the source of the explosion...

However, there's always a chance the dial of the meter on the table comes flying after the event and hits the operator in the head...  :-DD

I'm not sure I follow.  Are you suggesting because it is a pen meter that the operator would be holding it where a meter with leads, they would be holding the leads and not the meter and this means the pen is less safe?  There could be some merit to that. 

That knob flew about 8' across the room and hit the wall. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 12, 2016, 12:58:45 pm
Well, my reason to assume the relative safety levels is based on the distance between the operator's body and the source of the explosion...

However, there's always a chance the dial of the meter on the table comes flying after the event and hits the operator in the head...  :-DD

I'm not sure I follow.  Are you suggesting because it is a pen meter that the operator would be holding it where a meter with leads, they would be holding the leads and not the meter and this means the pen is less safe?  There could be some merit to that. 
Joe, yes I am suggesting that.

One ergonomic aspect that I noticed with the pen DMM I have is that it is impossible to do the "hand on the pocket" rule if measuring high energy circuits, unless an alligator clip on the negative side is used. With a traditional table DMM you can also hold both probes in one hand. Anyhow, I digress.

That knob flew about 8' across the room and hit the wall.
I have experienced situations where flying remnants of average energy short circuits (mains) were targeted at me. Fortunately I used glasses at the time, which saved my eyes from any damage.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 12, 2016, 05:12:24 pm
That make sense.  There was a couple of clips included with the last meter that will fit over both ends.   In practice, I would never use a meter like this in the first place.  One wrong click on the dial and they are in current mode.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2016, 09:07:03 pm
All tucked in and waiting for things to get stable....

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2016, 09:43:38 pm
Attached shows the previous data as well as the test I ran today.   Note that instead of running them from -10 to 40C, I ran them from -20 to 60C.   I also changed from a 1V reference to 1mV.  We can see running with 1mV we can now actually get some idea about their drift. 

While I have heard how poor the UT61E was, it is not as bad as the $300 Extech! Now again, I have been inside that Extech but I very much doubt anything I have done would have changed its TC.   The UT181A that I damaged, repaired, modified the PCB out performed my BM869s.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2016, 04:40:33 pm
Comparing 5KY's UT61E with mine. Even thought the two meters are similar, I have a feeling UNI-T belongs to a resistor of the month club.   The JML datasheet shows +/-200ppm.  Not sure what the others are.  May just swap out the few passive parts and see what difference it makes.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 21, 2016, 04:07:35 am
Can you make a $50 UT61E more temperature stable than Dave's BM235 without buying an expensive reference?  What about making it even more stable than the BM869S and keep the parts cost under $1.00? 

Stay tuned for the next video where I will show how I pull it off.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 21, 2016, 11:22:37 pm
Here you go, for less than 35 cents in parts in single qtys, the UT61E takes on my two Brymen meters.   

https://www.youtube.com/watch?v=0ObW8AA42OY (https://www.youtube.com/watch?v=0ObW8AA42OY)
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on November 21, 2016, 11:44:27 pm
Best Eleotron, couldn't even afford a "c".
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2016, 04:10:05 am
2017 is shaping up... 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on December 21, 2016, 08:34:56 am
2017 is shaping up...

And shipping out by the look of it, what's in the box ?.   :-//

The suspense is killing me meters.   :-BROKE
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 07, 2017, 03:55:04 am
That was some box that I had shown up.  Name was pretty close.   

That analog meter is still sitting in the box and I had planned to run it next.   I think I am going to side step that and run this CEM meter. I had wanted to run the Extech EX540 but it was in such poor condition and needed some repairs.  So next up, the CEM DT-9939.   If there is anything you would like to see while it is still functional, just ask.   

http://www.ruby-electronics.com/store_item/DT-9939_Waterproof_Industrial_Wireless_USB_RMS_Multimeter_with_Capacitance_Frequency_Duty_Cycle (http://www.ruby-electronics.com/store_item/DT-9939_Waterproof_Industrial_Wireless_USB_RMS_Multimeter_with_Capacitance_Frequency_Duty_Cycle)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 10, 2017, 02:50:31 pm
I have completed my review of the CEM DT-9939 I bought from Ruby Electronics for $120.  40,000 count, AC+DC, wireless, tri-display, GS and TUV certified.     

https://www.youtube.com/watch?v=wkrbohiuUwU (https://www.youtube.com/watch?v=wkrbohiuUwU)
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on January 11, 2017, 03:50:27 am
G'day Joe,

Thanks for the video it was very good and I think you did pretty well on price for the CEM, Jaycar down here did have them for $229 AUD not long ago but recently put them up to $279 AUD, I've owned a few CEM meters over the years and recently gave one away to my brother in law whom I don't like very much, one thing to watch out for is they have a tendency to go out of specification with even the slightest bounce on the bench because of the trimmers, easy fixed but still a pain.

Jaycar do offer a life time guarantee on the CEM meters which I have tested and they did come to the party on one I blew up, one thing to watch out for though is their current catalogue states a life time guarantee but the website states only 9999 months which equates to only 833.25 years, this could be a bit of a worry for immortals.

Jaycar - Digitech QM-1576
https://www.jaycar.com.au/ip67-true-rms-cat-iv-dmm-with-meterbox-smartphone-app/p/QM1576 (https://www.jaycar.com.au/ip67-true-rms-cat-iv-dmm-with-meterbox-smartphone-app/p/QM1576)

Title: Re: Handheld meter electrical robustness testing.
Post by: 3nigm4 on January 11, 2017, 08:16:30 am
...one thing to watch out for is they have a tendency to go out of specification with even the slightest bounce on the bench because of the trimmers, easy fixed but still a pain.
I think that adding a voltage reference (like done un the UT61E) may improve this... I'll take a look... if I find it's schema

Jaycar do offer a life time guarantee on the CEM meters which I have tested and they did come to the party on one I blew up, one thing to watch out for though is their current catalogue states a life time guarantee but the website states only 9999 months which equates to only 833.25 years, this could be a bit of a worry for immortals.
:-DD :-DD :-DD

Jaycar - Digitech QM-1576
https://www.jaycar.com.au/ip67-true-rms-cat-iv-dmm-with-meterbox-smartphone-app/p/QM1576 (https://www.jaycar.com.au/ip67-true-rms-cat-iv-dmm-with-meterbox-smartphone-app/p/QM1576)
I investigated a bit, disassembling Meterbox apps to look for names used in BT connetion; I planned to replace the internal RF module with a BT module, but trying an HM-10 (BLE), it is seen by apps only if named DM-9969 or DM-9989 that are those sold with a BLE module.
In the code I've found DT-9939 but even a strange DT-9939B... looking to QM-1576 seems that it is the only DT-9939B on the market: a DT-9939 with a BT module while the one with RF module is the QM-1575

Edit: the QM1575 cost even less :-+
https://www.jaycar.com.au/40-000-count-ip67-true-rms-cat-iv-dmm-with-wireless-usb-and-storage/p/QM1575 (https://www.jaycar.com.au/40-000-count-ip67-true-rms-cat-iv-dmm-with-wireless-usb-and-storage/p/QM1575)

Edit2: it seems no more listed as an available choice (thanks to Muttley Snickers report)
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on January 11, 2017, 09:00:18 am
Greetings 3nigm4,

I think you might find that the Jaycar listing for the QM-1575 you posted could in fact be a stale Google page as Jaycar no longer list that model in either their current paperback catalogue nor on their site when you search for that model number or check the list of digital multimeters. If they were still available at that price then I would buy one tomorrow without hesitation.

 :) :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: 3nigm4 on January 11, 2017, 09:43:51 am
It seems they forget to remove the page too  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joseph nicholas on January 11, 2017, 10:09:37 am
Hi, The reviews and testing are excellent on joe's posts.  Of all the meteres he shows in the rap up, the cheap Uniti e model looks to be the best bang for the buck.  The tri state display on the Jaycar meter featured there and the water proof thing are nice but I guess I admit I don't get it.  All these expensive meters would most likely would not be used in the field.  In a work setting, I think something like a MF-47 analogue Simpson clone would make me more comfortable since it can measure up to 2.5K without blowing up.  Most of these high end meters are going to see service in the on the bench, not during a rain storm hanging from a high tension pole. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 11, 2017, 01:13:24 pm
...one thing to watch out for is they have a tendency to go out of specification with even the slightest bounce on the bench because of the trimmers, easy fixed but still a pain.
I think that adding a voltage reference (like done un the UT61E) may improve this... I'll take a look... if I find it's schema

If you find a schematic for it, please post it.  I have used the Extech for several years now.  Beyond loaning it out where one person felt the need to turn the selector past the dead stop along with getting it back with a blown fuse now and then, no problems.

That selector switch could stand a redesign, along with the PCB and front end..... 

Hi, The reviews and testing are excellent on joe's posts.  Of all the meteres he shows in the rap up, the cheap Uniti e model looks to be the best bang for the buck.  The tri state display on the Jaycar meter featured there and the water proof thing are nice but I guess I admit I don't get it.  All these expensive meters would most likely would not be used in the field.  In a work setting, I think something like a MF-47 analogue Simpson clone would make me more comfortable since it can measure up to 2.5K without blowing up.  Most of these high end meters are going to see service in the on the bench, not during a rain storm hanging from a high tension pole. 

Thanks, glad you enjoy them.  I guess when it comes to what products we buy, what we call high end, the bang for the buck and what we are comfortable is a matter of choice.  For work, it may be mandatory.

One day, I may run something I would consider higher end.   The 87V which is the highest cost meter I have ever looked at did very poor so I think I would want to try a Gossen with their GDT protection.  It can't be as bad as the Keysight meter I looked at. Someone asked me about running a new HIOKI pocket meter and had I been able to find one, I would run it.

The 61E aside from not being certified, no backlight (in case I crawl under the car), no temperature and the fact that it can be damaged with such little effort, I would have no need for it.  But the HF free meter may be a better bang for the buck.  I know it was not in the line up because I have destroyed every one of them I have looked at.   This 61 is the 3rd one I've looked at and the only reason it is still alive it because it was reengineered by a state side hobbyist.   Same for the UT181A. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 14, 2017, 02:34:28 am
A friend of mine had purchased one of the Ruby CEM meters and received it today.   Theirs was also the blue CEM with the TUV/GS markings.  They gave me their old meter.  Picture attached.  I plan to keep this one because I find it so funny to see the Vicor logo on it.   

Much nicer shunt and a replaceable fuse than what HF gives away now. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 14, 2017, 07:47:08 pm
Viewership has grown enough that today I have started working on an FAQ sheet for this testing.  Hoping that will help out down the road.  Just finished reading every YT comment.  Once completed, feel free to add comments about common questions you feel I have not addressed.   

I have noticed people trying to use the channel to run ads now.   I am not sure if reporting them (youtube allows it) really helps.  So far, I just add them to the banned list.  Strange as my account should be so far in the noise floor, seems using a more popular channel would make more sense.   

Time to read 45 pages of this thread.  The down side of testing....

*******************************
Wow, that's a long thread.   I erased a few posts that didn't add any value (mostly where I would update the spreadsheet) and I have a bad habit of having extra blank lines at the end of posts which I cleaned up. 

Two years of meter carnage and we remained civil enough that the thread remained open!   :-DD   

Lot's of great comments and questions.  Will make a for a good document moving forward.  Not that people will read it but at least I can now just refer to it if someone asks a common question.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 15, 2017, 01:35:22 am
Answers to Frequently Asked Questions may be found in the following link. 

https://docs.google.com/document/d/1gEPFeOZpsNSm0-7sA98w2P5XE5x77Oal9dQEYvQnF6g/edit?usp=sharing (https://docs.google.com/document/d/1gEPFeOZpsNSm0-7sA98w2P5XE5x77Oal9dQEYvQnF6g/edit?usp=sharing)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 15, 2017, 12:53:55 pm
Viewership has grown enough that today I have started working on an FAQ sheet for this testing.  Hoping that will help out down the road.  Just finished reading every YT comment.  Once completed, feel free to add comments about common questions you feel I have not addressed.   

I have noticed people trying to use the channel to run ads now.   I am not sure if reporting them (youtube allows it) really helps.  So far, I just add them to the banned list.  Strange as my account should be so far in the noise floor, seems using a more popular channel would make more sense.   
I guess that is the downside of being mildly popular... Perhaps they think they can get away with the fact the channel owner likes the traffic of the comments to increase its own popularity... I don't know - Youtube ratings and algorithms can be mysterious.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 15, 2017, 03:57:44 pm
Viewership has grown enough that today I have started working on an FAQ sheet for this testing.  Hoping that will help out down the road.  Just finished reading every YT comment.  Once completed, feel free to add comments about common questions you feel I have not addressed.   

I have noticed people trying to use the channel to run ads now.   I am not sure if reporting them (youtube allows it) really helps.  So far, I just add them to the banned list.  Strange as my account should be so far in the noise floor, seems using a more popular channel would make more sense.   
I guess that is the downside of being mildly popular... Perhaps they think they can get away with the fact the channel owner likes the traffic of the comments to increase its own popularity... I don't know - Youtube ratings and algorithms can be mysterious.

Yea, I don't mind putting in the time to make these tests happen, buying the meters and make it all available for free.  But why would someone feel it's ok to try and make a buck off it, just poor character IMO.   
Title: DT-9939 Weird/"Crashing" Behavior -- Turned Out To Be the Battery
Post by: gby on January 21, 2017, 02:39:17 pm
I was in the market for a fairly high feature high resolution meter that could interface with a PC when I read the last few posts and watched Joe's CEM DT-9939 video review.  Being curious I sought out Ebay to see what they were going for there and found a number of active auctions with starting price of $89.95 with $19.95 shipping.  Some listings by Ruby Electronics and some by other seller names....but all shipping from Saratoga, CA with the same prices.  Long story short I got one for $109.90 delivered and just got it yesterday.  I bought from an alternate seller name ab3c but inside the case was a Ruby Electronics orange card.  So far I like it and it seems reasonable for what it is....a middle level meter in accuracy but high level meter in features, resolution.

However, when I first started checking it out it did some weird things that made me think it was defective.  The first time I turned the knob to Hz% with leads open circuit I got 0's and the meter froze.  Turning to another position did nothing.  I had to go to turn the knob to the off position to get it working again.  I then tried Ohms followed by the continuity setting.  In the continuity setting once I shorted the leads the beeper started and continued going even when I un-shorted the leads  :scared:!  I turned the knob to another position and the beeping continued.  I had to go back to the off position to un-freeze the meter.  It did this multiple times.

To make a long story short it was the Golden Power 9V battery included with the meter.  Open circuited it measured 8.3 Vdc but loaded with 220 Ohm it dropped right away to 6.9 Vdc.  Removing the load it went back up to 8.3 Vdc.  With this battery in the meter the low battery indication did not come on since at low load it was high enough.  With a load like the continuity test it seemed it went low enough to "crash" the meter chip.

I put in a fresh Duracell 9V battery and everything works as it should.  So, word to any owners out there that old/high droop batteries may not trigger the low battery indication but the meter works badly/"crashes".

The included Golden Power 9V battery was stamped 2014-07 on the bottom and the calibration check sheet was dated 2013-5-14.  So, I highly suspect these are old stock meters that were made at least 2 years ago.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 21, 2017, 08:55:21 pm
Hope you enjoy the new meter.  A friend bought one as well and when he went to turn it on, the meter was dead.  Same GP battery.  What was strange is the battery reads about 9.4 volts until you plug it into the meter.  Then it's dead.  Almost like it has a bad crimp.   I saved the battery and plan to pull it apart.   

Problems I have seen with them so far:

Antenna placed on wrong side of PCB shorting to shield
Missing shield
Ground spring cut
Switch contacts not making contact with PCB
Cracked plastic sleeve over banana connector
Open solder joint in RF adaptor
Missing star washer
Missing screws in RF adaptor
Shield over control IC not placed correctly or poor soldering in this area

As long as you are willing to double check the meter over and correct any quality problems, its a great meter for the price. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 26, 2017, 12:51:10 am
I am not sure why but my subscribers are starting to increase at a faster rate.  It seems only fitting we should do something special once we hit 2000 so I have opened a poll where you can decided what meter should be ran to celebrate this milestone. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 30, 2017, 12:47:36 am
This was the second analog meter I bought to check.  It was sold under the Tekpower brand as a PN# TP 7050.  It appears the OEM is Ketai Instrument  KTI and their PN# is KT-7050. 

I've picked this thing up at least five times to run it, but I keep putting it back in the box.

The meter is made with mostly surface mounted parts.  Its much nicer than the first one but costs about 3X.  Notice they have a couple of MOVs in there.  There is a note in the lower right corner of the meter plate "fuse & diode protection".

One thing I don't like is they don't have a separate connector for the low current input.  Then they use glass fuses.  If the fuse blows, the meter will no longer function.  So, if I hit this thing with a transient and the fuse blows, I would have to continue to replace it.  So here lies the reason the meter sits.   

I thought about trying to modify their design similar to what I had done with the first analog meter and see if I could improve it but the schematics don't appear to be available.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 01, 2017, 12:10:06 am
A few people have commented about using my grill starter for running some simple ESD tests on these meters.  Some think it's pretty harsh compared with the real world.  I am thinking about trying to make my own simulator.  A quick search, I see it's come up before. 

https://www.eevblog.com/forum/projects/diy-esd-gun/ (https://www.eevblog.com/forum/projects/diy-esd-gun/)


After I damaged the UT181A, I was asked about the open circuit voltage of the starter and decided to add a little section on ESD testing.  You can see that here:

https://youtu.be/1kYcY2ogmqo?t=113 (https://youtu.be/1kYcY2ogmqo?t=113)

What I would like to do is design one that would follow the EN61326 standard.  My plan is to run direct contact and just use a fixed voltage.  There are some differences between the IEC standards and what we used to call the HBM.  Rise times are much faster.   When I designed the other transient generators, the rise times are actually fairly slow.  I can see this being a challenge for the ESD pulse.   

Another key difference between these standards is the rise time of the voltage strike. The HBM model specifies a rise
time of 25 ns. An IEC pulse has a rise time of less than 1 ns and dissipates most of its energy in the first 30 ns. If it
takes 25 ns to respond, the device rated using the HBM specification can be destroyed before its protection circuits are
even activated (see Figure 1).



I have attached a paper published by ON Semi that explains a little more about the ESD pulse.  The paper also gives some background and what you could expect to find in the wild.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 01, 2017, 06:15:42 pm
I have yet to find any pictures of a gun taken apart.  This article mentions the case design. 
http://incompliancemag.com/article/a-brief-history-of-electrostatic-discharge-testing-of-electronic-products-2/ (http://incompliancemag.com/article/a-brief-history-of-electrostatic-discharge-testing-of-electronic-products-2/)

Time to do a little patent research. 
https://www.google.com/patents/US4926285 (https://www.google.com/patents/US4926285)

If I can get something made that is better than the grill starter (seems like 1A 5ns pulse would not be too hard to improve), my plan would be to test the meters with the leads supplied with them.   I am not really sure how they test them for the EMC cert.   Rerun  the meters I have and then maybe get a couple of UNI-T or anther Vici that failed and rerun them as well. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 02, 2017, 01:48:30 am
The more I read, the more I wonder if it could be done at the home hobbyist level.  I think I just need to try a few ideas and see how things look.  The standard calls for 4KV.   Went through the junk pile, one of these may be alright for the storage.   I plan to mount it on the copper board below.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 02, 2017, 05:56:00 pm
I was looking for a test procedure that describes the test setup for multimeters in more detail and found the attached.   Section 5 covers the ESD testing.  Now, I have to believe even the UT181 would survive this test and question the point of it.  I suspect other test houses may perform it differently but really don't know.

Using the handheld as basically a moveable bench meter, I can see having the common lead connected to ground of the instruments.  In my case, this is also earthed.   I won't always use the leads supplied and some are very short.   Now it's winter, the house is VERY dry and I walk to my office (all carpet) and approach the bench.  No wrist strap and I don't touch the mat.  Rather I touch the other lead to the meter at the tip.  I was really expecting they would have one lead attached to the plain, and the other lead floating then touching the tip of the lead.  Criteria B means it must self recover.   Then I would run it in every switch setting and I would test the meter in the end to make sure the thing still works. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 04, 2017, 06:37:23 pm
I finished my first attempt to construct a home made ESD gun.   The grill starter would put out about a 1A 5ns wide pulse was all but the open circuit voltage was around 15ish KV.  The gun starts with a regulated 4.0KV supply and I plan to again only do direct contact assuming I get something that works well enough.   

Again, my home made 2 ohm target is attached to the scope with a 26dB attenuator and about a meter of RG400.  So for example, 100mV would be about an ampere.  The standards don't really cover the open circuit waveforms.   They want 15A in that sub ns range.  Then decay to roughly 8A in 30ns and 4A in 60ns.

There is some risk playing around with this gun.  The LeCroy 64xi display will flicker then there is always the stupid USB problems.   The 64xi does not have near enough top end to see what is really going on but I don't like playing with the faster scope while I am working out the design.   So here are the first waveforms off it.  At about 60ns the scope is showing 350mV or about 3.5A.  Construction is pretty poor right now but it's already looking better than the grill starter.

I was digging into that first test report where they tested the meter without the leads.  Looking at the EN 61326-1:2013

3.11
port
any particular interface of the specific device or system with the external electromagnetic
environment
EXAMPLE See Figure 1 for an example of Equipment Under Test (EUT).
Note 1 to entry: I/O ports are input, output or bi-directional, measurement, control, or data ports.
Note 2 to entry: Within this document, ports intended to be connected with earth potential for functional reasons
(functional earth ports) are considered as I/O ports
Note 3 to entry: Within this document the protective earth port (if any) is considered as part of the power port.

5.2.4 I/O ports
Where there are multiple I/O ports, which are all of the same type, connecting a cable to just
one of those ports is sufficient, provided that it can be shown that the additional cables would
not affect the results significantly.
If not otherwise specified in more specific parts of the IEC 61326 series, electrostatic
discharges shall not be applied to inner pins of plug-in ports or cable connectors (but to
connected connectors accessible during the intended use of the EUT).


6.4.3 Performance criterion B
The equipment shall continue to operate as intended after the test. No degradation of
performance or loss of function is allowed below a performance level specified by the
manufacturer, when the equipment is used as intended. The performance level may be
replaced by a permissible loss of performance. During the test, degradation of performance is
however allowed. No change of actual operating state or stored data is allowed. If the
minimum performance level or the permissible performance loss is not specified by the
manufacturer, either of these may be derived from the product description and documentation
and what the user may reasonably expect from the equipment if used as intended.


IMO, that first reports ESD test was pointless and did not follow the sprit of the standards.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 04, 2017, 08:41:25 pm
After several more attempts, shown attached to the higher BW scope.  2 amperes per division.  It's an improvement, but getting the 15A out of it with any sort of edge is not trivial..  Starting to see why there are no home made guns out there. 

Touching the this onto my fingers, compared with the grill starter, this is a pretty good poke.   Feels more real worldish from my finger ESD experiences...  :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2017, 12:15:24 am
Much better.  2A / division, 15A peak.   
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on February 05, 2017, 12:41:47 am
Nice Joe, did we never did doubt you'd get there.  :clap:

More carnage awaits.  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2017, 12:58:09 am
Thanks.  It's getting there but that 4ns edge is still too slow.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on February 05, 2017, 01:05:28 am
Thanks.  It's getting there but that 4ns edge is still too slow.
Oopps, right, yeah I did read that the other day.

Quote
An IEC pulse has a rise time of less than 1 ns and dissipates most of its energy in the first 30 ns.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2017, 06:03:41 pm
Trying a few new ideas today.  It's come a long way since I started working on it.  Shown zoomed out and in.   Around 1.5ns now. 

I wonder if I inject this across the two leads, would ANY meter survive.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2017, 08:18:25 pm
Here are five overlaid shots.  10A peak with a sub 500ps rise.   Also shown zoomed out.   The current is way too high at the 60ns and I have detuned it a little further.  My plan will be to keep the waveform lower than the IEC standard calls for.   

The next step will be to make some sort of box for it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2017, 09:13:44 pm
Looking at the distribution of 50 shots, about 70ps of error on the rise time.  Note how the scope misses finding the edge.  I have it throw out this data. 
Amplitude moves around about a half amp or about 5% error.

Scope showing about 10A peak, 7A@30ns and 3A@60. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2017, 09:21:39 pm
With the same setup, just the RG400 moved to the higher BW scope.  We can see the peak currents are closer to 11A.   The rise time is about 100ps less as well. 

IMO its pretty good for a home made gun. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 06, 2017, 12:57:42 pm
It's almost finished.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 06, 2017, 09:57:36 pm
Joe, this progress is incredibly interesting. Are you getting these values under load or open circuit?

I have cooked some ideas to create spark gaps years ago but had to postpone my plans due to newborn babies along the way. Give it a few years and "I'll be back". :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 06, 2017, 10:55:08 pm
Joe, this progress is incredibly interesting. Are you getting these values under load or open circuit?

I have cooked some ideas to create spark gaps years ago but had to postpone my plans due to newborn babies along the way. Give it a few years and "I'll be back". :P

Hello.  The IEC standards call out the calibration method for the guns.   The don't have much on the open circuit voltage but we know they want 4KV.   In that last picture, you can see my home made 2 ohm target and attenuators that I am using to get the current waveforms. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 07, 2017, 03:39:05 am
It's pretty much ready now.  Sorry John, this one's not getting a nice wooden case.   

Besides the pulsed output, the gun also has a DC output.  The display in the upper right is a ballpark of the voltage in KV.  Shown at 1.4KV and hooked to the Brymen using my high voltage attenuator.  Also shown are the target and grill starter.

Now I need a new free HF meter to try it out on....
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 08, 2017, 05:51:56 pm
The completed gun..

https://www.youtube.com/watch?v=Qimtx8z6FUQ (https://www.youtube.com/watch?v=Qimtx8z6FUQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: Daruosha on February 10, 2017, 03:59:49 pm
Keep up the amazing work man! I enjoyed a lot and your videos encouraged me to do some more research on ESD protection standards and tests. Thanks again.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 11, 2017, 07:48:44 pm
Keep up the amazing work man! I enjoyed a lot and your videos encouraged me to do some more research on ESD protection standards and tests. Thanks again.

Thanks and glad you are enjoying them.
Title: Re: Handheld meter electrical robustness testing.
Post by: Daruosha on February 13, 2017, 10:26:12 pm
It seems that I am having a hard time to understand and differentiate the safety vs robustness.

You managed to kill two fluke 87v's by puting a 1,500V pulse on their resistance measurement mode, however CAT IV 600V class, claims protection against 8,000V input surges an yes, at least the flukes failed safely.

Is it correct to conclude the CAT rating has nothing to do with the robustness and it is only a parameter of how a multimeter will fail in terms of safety?
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on February 13, 2017, 10:32:06 pm
It seems that I am having a hard time to understand and differentiate the safety vs robustness.

You managed to kill two fluke 87v's by puting a 1,500V pulse on their resistance measurement mode, however CAT IV 600V class, claims protection against 8,000V input surges an yes, at least the flukes failed safely.

Is it correct to conclude the CAT rating has nothing to do with the robustness and it is only a parameter of how a multimeter will fail in terms of safety?
Correct.
Joe's robustness testing demonstrates how a meter can survive (or not) ESD and common or not so common misuse.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 14, 2017, 03:03:29 am
And if I may add, I based my testing loosely around the IEC surge test.  This is part of the safety standards and the CAT rating you mention.  I did not do this to attempt to confuse or mislead people into thinking I was looking at safety.   There just are no industry standards that really covered what I was attempting to show (how robust the meters are compared with one another).  Of course, calling the thread, hear kitty kitty not that kind of CAT did not help I'm sure but I assumed people would figure it out.  :-DD

The big difference between what I am doing and what the standard calls for is the amount of energy available.  So while I now basically follow the open circuit voltage waveforms, I do not use the short circuit current waveforms.   I do use the 2 ohm source and limit the rise times.     Of course, if a meter did not break down, the current would not mater.   It would absorb very little of the energy available. But some meters do breakdown and rather than the meter possibly violently coming apart, they may spark a little is all.     

Way back when I first started testing, I was not using the standard waveform shape.  Another member had access to a standard generator and offered to test a Fluke 101.  Knowing this, I changed over to the waveform, but doubled the decay time from the IEC standard and I went up another KV.  Basically, I wanted to know that the Fluke 101 was actually going to survive.  The member repeated the tests and we got to see a Fluke 101 survive the real transients.   

More often than not, when a meter is damaged, I can't repair them.  I added a new generator that basically simulates the energy in a half cycle 440 CAT III bus.  I will put the dead meter into the AC volts mode and apply the high voltage wave that caused the meter to break down.  If the meter does break down, the half cycle simulator turns on and feeds all that energy into the meter.  I don't keep any metrics on that test and it's really only there to give some sort of perspective how the meters handle higher energy levels. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Daruosha on February 14, 2017, 03:42:16 pm
Thanks for sharing the idea behind the tests. Well, that's shane there is no ratting for multimeter robustness and no one the industry (i'd like to exclude you) has properly tested and rated the handheld multimeters for robustness. In fact it's quite surprising!

Anyhow your tests are pretty unique and I believe if you document all your tests methodology and their results, perhaps it could lead to a new trend and attract knowen manufacturers. I hope.

It sounds to much to ask, can we have all your test results in a single sheet including torture pulse duration and voltages? I found an Excel sheet, in the first post,  but it looks just a bit outdated and not well documented. Also how the various multimeter failed, they just failed with no explosion or something nasty happened too?




Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 15, 2017, 12:58:54 am
Thanks for sharing the idea behind the tests. Well, that's shane there is no ratting for multimeter robustness and no one the industry (i'd like to exclude you) has properly tested and rated the handheld multimeters for robustness. In fact it's quite surprising!

Anyhow your tests are pretty unique and I believe if you document all your tests methodology and their results, perhaps it could lead to a new trend and attract knowen manufacturers. I hope.

It sounds to much to ask, can we have all your test results in a single sheet including torture pulse duration and voltages? I found an Excel sheet, in the first post,  but it looks just a bit outdated and not well documented. Also how the various multimeter failed, they just failed with no explosion or something nasty happened too?

If you watch my videos, the last meter I tested was the CEM DT-9939.  This is the last meter entered into the spreadsheet, so it appears up to date.   Looking at the header,  the peak amplitude (voltage), source impedance and FWHH (I would guess what you are calling pulse duration)  are shown for each level.  The videos for each test are online so if someone wanted to dig into what was done, you can go so far as to watch it.  There you would find that I subject each mode of the meter to five transients each both positive and negative (again right from the IEC standards).   I already covered what my goal was so I am not sure why you would ever think a meter would explode during my testing.  There is a link to a FAQ on my YT About page.  That may provide some additional information.

I spoke with a few companies about their testing and wanted to know if they would make their data public and in all cases was told no and it is one reason I started running these tests and making them public.  If you look at the reports that are available to the public, what information do you find?   Not too long ago I linked one from TUV and that had a lot more detail than most!

If someone wanted to really run this test on a bigger scale, personally I would just follow the IEC surge test using all of the standard equipment.  I would get that generator on the AC mains and I would build a nice blast room to go with it!  :-DD   I would step the voltage in small increments and functional test the meter between each step as I do and document the results.   Simple enough to do, but a huge investment.  For a company, what would be the advantage to making this data public?  Some companies like Fluke may be able to make a marketing spin with it but then they would also have to show their 87V as well.  It's one thing for a hobbyist to say the 87V is not very robust, it would be a whole different game for Fluke to come out with data showing where it fits.   I just don't see the companies ever doing this.   Even if they did, I would be concerned the testing would be corrupt.   Look at that TUV Intertek report where they ESD test the meter without the test leads.  The average person may not care but if bought a meter and knew this was how they got it to pass, I would not be happy.    Really it seems it should be a not for profit, independent group running the tests as a watchdog public service.  This would require some major cash flow. 

I would like to see it on a large scale.   Public education would need to be part of it. I really don't see how you would turn it into a business.  The money needs to come from somewhere.    Look at the comments in this thread and consider this is a tech sort of audience.   I suspect the majority of people who would purchase a meter could care less about this sort of thing, so they are not going to fund it.  You need to make enough to feed and house yourself along with your staff.   Seems like a rough road. 

Just blabbing...   If you would like to make a go of it your self I would be interested in hearing about it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2017, 12:09:26 am
i wanted to try to understand the amount of energy released into a DUT under test, i ended up finding this https://www.onsemi.com/pub/Collateral/TND410-D.PDF (https://www.onsemi.com/pub/Collateral/TND410-D.PDF)

so in the  IEC 61000-4-2 level 4 contact test, 8kV (it says 30A max, i thought there is no limit since it is suppose to be a surge?), i calculate that the amount of energy the DUT must absorbed if 100% discharged in 30ns = 28.8J, but that doesnt look right as there is a discharge curve and the actual amount of energy absorb look more like 50% (15J?) in 30ns and maybe 75% (22J?) in 60ns? is my guess somewhat  in the right direction?

i assume if DUT survived the 30ns (or 60ns) 8kV discharge, the DUT wins (irregardless of how much energy was not absorbed but left over in the discharge capacitor) am i right?

and if based on human body model, the max current it states is 5.33A for 8kV, so much lower (energy going thru DUT = 5.1J ?).

with this, i assume that if i include in circuit design some kind of TVS with 50J of absorption capability, it is sure way to survive 99% of mishaps? yes?

Think mJ.  My big generator puts out about 20 when cranked up.
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on February 20, 2017, 03:41:25 am
and if based on human body model, the max current it states is 5.33A for 8kV, so much lower (energy going thru DUT = 5.1J ?).

with this, i assume that if i include in circuit design some kind of TVS with 50J of absorption capability, it is sure way to survive 99% of mishaps? yes?

Think mJ.  My big generator puts out about 20 when cranked up.

Drat.  I was hoping it would be MJ.

"The meter didn't survive the test, but at least the scope in the room on the other side of the house did!"

 :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2017, 11:17:26 am
My scope's LCD was wigging out while I was working on the new gun.   It's also common for the USB devices to have to be power cycled in my office. 

For high energy transients, I like watching this guy's channel. 
https://www.youtube.com/watch?v=coW1RHUsf_I (https://www.youtube.com/watch?v=coW1RHUsf_I)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on February 20, 2017, 11:20:48 am
I only have two of the latest hand soldered pre-production prototypes, I ain't sacrificing one to the impulse gods  :P
it hasn't been Intertek tested yet.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2017, 11:40:00 am
That's fine.  When I posted the comment about my offer, I was thinking we would run nondestructive tests on it. Are they getting both the EMC and safety certs?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 23, 2017, 04:07:53 am
What's in the box.

https://www.youtube.com/watch?v=PeQpyn3926k (https://www.youtube.com/watch?v=PeQpyn3926k)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on February 24, 2017, 05:22:02 am
Joe, thanks for the tour of the box. Pretty handy checker.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 25, 2017, 01:54:53 am
The 87V on the chopping blocks.  Interesting, they only look at the AC voltage mode and they do not appear to functional test the meter between steps.  How do they know where it fails?

https://www.youtube.com/watch?v=Cij9I1y84kc (https://www.youtube.com/watch?v=Cij9I1y84kc)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 25, 2017, 10:13:08 am
The 87V on the chopping blocks.  Interesting, they only look at the AC voltage mode and they do not appear to functional test the meter between steps.  How do they know where it fails?

You can clearly see it jump in the air at 2:02  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 25, 2017, 07:28:38 pm
A jumping meter is the criteria for pass/fail.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: zaoka on February 26, 2017, 01:07:16 am
Joe did you ever seen Iwatsu multimeters?

Like  Hioki these are top class stuff...  :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 26, 2017, 01:34:37 am
I think I used one of their scopes many years ago but I have never seen any of their handhelds.   

The one in this link does not look too bad:
https://www.eevblog.com/forum/testgear/iwatsu-voac22-dmm-teardown/ (https://www.eevblog.com/forum/testgear/iwatsu-voac22-dmm-teardown/)
Quote
Yokogawa is the OEM manufacturer for Iwatsu

Do you own one? If so, do you like if?
Title: Re: Handheld meter electrical robustness testing.
Post by: zaoka on February 26, 2017, 02:34:30 am
These are made under different names:

Yokogawa TY720 https://www.youtube.com/watch?v=goj8HomoKJY (https://www.youtube.com/watch?v=goj8HomoKJY)
Kyoritsy KEW1062
...

Iwatsu makes bench meters, I seen older model and never owned it. That latest model is really fancy https://www.iti.iwatsu.co.jp/en/products/voac/voac7602_top_e.html (https://www.iti.iwatsu.co.jp/en/products/voac/voac7602_top_e.html)

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 26, 2017, 03:15:30 am
Joe, these are interesting clips. The fact they don't functionally test the meter after each "shock" is most probably related to the nature of these tests: they are supposed to contain and withstand arc flashes instead of "surviving".

I suspect the power strip in fumes is most probably due to the varistors.

I do prefer the results of your tests, as they measure the amount of headache a DMM can give you (as I only work with average power circuits).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 26, 2017, 03:38:38 am
Joe, these are interesting clips. The fact they don't functionally test the meter after each "shock" is most probably related to the nature of these tests: they are supposed to contain and withstand arc flashes instead of "surviving".

I suspect the power strip in fumes is most probably due to the varistors.

I do prefer the results of your tests, as they measure the amount of headache a DMM can give you (as I only work with average power circuits).

The opening statement was:
"It's important that test instruments and other electrical test tools are independently evaluated to make sure they can survive high voltage transients"

At 9:29
"With stout input protection our test instruments are built to survive"  then they go on to show you some big boy toys. 

Now I'm not suggesting that you need to actually test the instrument to know that it survived the test....  Of wait, that's exactly what I am suggesting!  Of all the meters they sell, the one that failed at the lowest level during my tests is shown to be a superstar.   :-DD 

Of course, I wouldn't claim a meter passed ESD without ever testing it with the leads.
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on February 26, 2017, 06:18:51 am
That was a great video update. You fooled me at first... ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 27, 2017, 04:54:58 am
I finished testing the Woods DMMW3.  I should have the video and spreadsheet uploaded tomorrow. 

Had some fun with the old 101 and 107 while I was at it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on February 27, 2017, 05:14:54 am
Any chance you'd do a video on the Aneng AN8002 cheapie? I just keep thinking about seeing the little fella in the box, since somebody posted about the AN8001 a few months back. I say the 8002 just for the temp measurement
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 27, 2017, 05:53:46 am
Any chance you'd do a video on the Aneng AN8002 cheapie? I just keep thinking about seeing the little fella in the box, since somebody posted about the AN8001 a few months back. I say the 8002 just for the temp measurement

 :-DD :-DD :-DD

Ok, here's the deal.  I was out of coffee and needed to order some.  A few people had asked about this meter and I ended up with a KASUNTEST ZT102 and the KT6666 along with my coffee.    The ZT102 looks very close to the one you are asking about.  There are a few videos on YT for it.  If you want to see these stressed to failure, stay tuned...

In the meantime.
https://www.youtube.com/watch?v=6mRRrYt-kbI (https://www.youtube.com/watch?v=6mRRrYt-kbI)
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on February 27, 2017, 06:16:35 am
Really got to wonder how many names they're selling these under.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 27, 2017, 05:39:20 pm
The Woods DMMW3 pocket multimeter

https://www.youtube.com/watch?v=TN-tvr_QxzY (https://www.youtube.com/watch?v=TN-tvr_QxzY)


The ZT102 will be next..
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on February 27, 2017, 07:03:23 pm
IMPRESSIVE video, as always! I happen to know how much time it takes to make videos. Getting all that testing done, and uploading in a day, is crazy fast. Then you actually repair the meter, geez, wish I had the knowledge and skills. You really LIT the CANDLE, several times.

Looks like a better meter for pocket use then my old Radio Shack "clamshell" meters. I would never test current with it anyways, but for quick voltage and continuity tests would seem handy for $30. Also, I don't have anything that small that can read Hz.

Thanks once again for taking all that time and effort to educate us with these tests. Don't know of anyone else willing to fry meters like you do!

Look forward to the ZT102 video.
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on February 27, 2017, 07:04:06 pm
It would be neat to see how it fares with more space/creapage distance.
Looking forward to the zt102.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 28, 2017, 01:47:44 am
IMPRESSIVE video, as always! I happen to know how much time it takes to make videos. Getting all that testing done, and uploading in a day, is crazy fast. Then you actually repair the meter, geez, wish I had the knowledge and skills. You really LIT the CANDLE, several times.

Looks like a better meter for pocket use then my old Radio Shack "clamshell" meters. I would never test current with it anyways, but for quick voltage and continuity tests would seem handy for $30. Also, I don't have anything that small that can read Hz.

Thanks once again for taking all that time and effort to educate us with these tests. Don't know of anyone else willing to fry meters like you do!

Look forward to the ZT102 video.

Thanks. 

Yes, it's a fair amount of time to run a meter.  The manual ranging meters are the worse!  Or meters that have a lot of features and just refuse to die.   :-DD   

I knew when I saw the first pictures that this meter was not going to do well.  It's just too tight.   Normally there is little I can do to repair a meter.  Most of the time I will damage some hard to get part making them recycle bin filler material.   

Personally, I will take function over form.   The smallest meter that I actually like is that 101.  That thing is just so robust.   People were complaining about it not having a current input and I always felt that was a plus.   It prevents non experienced electrical people from making at least one mistake.  And if you blow it up, you know there is a good story behind it!  :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 28, 2017, 01:54:57 am
It would be neat to see how it fares with more space/creapage distance.
Looking forward to the zt102.

I had looked at some inexpensive pocket meters before and I took a calibrated dremel tool to is to improve the brakedown.   This put more an more stress on other parts until it failed.

I don't think there is much I could do to improve the robustness of that meter because of the lack of space.  IMO, I would have left out that 200mA circuit and tried to make the meter more robust using that space.

I watched a few reviews of the ZT102.  The reviewers all seemed to like it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on February 28, 2017, 02:06:42 am
I was thinking about the low current range. For the most part, I very rarely actually measure current below .5 Amps. Especially when it comes to home wireing, I don't do it.
Title: Re: Handheld meter electrical robustness testing.
Post by: kwass on February 28, 2017, 05:11:28 am
The Woods DMMW3 pocket multimeter

Thank you for that in-depth testing!!!
The DMMW3 did better than I thought it would in your torture test.  It's not a Fluke but I still like it.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 28, 2017, 01:08:43 pm
The Woods DMMW3 pocket multimeter

Thank you for that in-depth testing!!!
The DMMW3 did better than I thought it would in your torture test.  It's not a Fluke but I still like it.

If we only consider the meters ran after I changed my test setup, it's pretty bottom of the barrel. Attached, the top graph is roughly the number of meters that failed each test. The lower graph shows how many meters survived after each test. 

Many people mention the Fluke 87V is the gold standard.  I believe that as well.  Notice that large peak in the top graph and the sharp roll off in the lower?  Once we get beyond that we are starting to see the better meters stand out.  Products that are more robust than the 87V are to the right of that hump.   

Dave's rebranded Brymen 235, the Fluke 115, the 101, the 107 and even that HIOKI I looked at are really in a whole different class when it comes to their front end robustness.   This is where I am expecting Dave's 121GW to fall in.

Some meters will place the high speed clamps after the switch.  The Woods is not like that.  Once I damaged the meter the first time and repaired it,  I only tested the meter in its voltage mode.   You may believe the meter was just running all fine and dandy but we know the meter was damaged again right away.   It was the same circuit and with those clamps not being switch out, the  would fail just like before.

For me personally, $30 for the Woods or just under $50 for the 101 it's no contest. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 28, 2017, 07:51:37 pm
The opening statement was:
"It's important that test instruments and other electrical test tools are independently evaluated to make sure they can survive high voltage transients"
Yes, you are right. I glossed over these statements.

At 9:29
"With stout input protection our test instruments are built to survive"  then they go on to show you some big boy toys. 

Now I'm not suggesting that you need to actually test the instrument to know that it survived the test....  Of wait, that's exactly what I am suggesting!  Of all the meters they sell, the one that failed at the lowest level during my tests is shown to be a superstar.   :-DD 

Of course, I wouldn't claim a meter passed ESD without ever testing it with the leads.
Likewise. As I told you before, I prefer your tests as they give you a measure of the headache you will have with your equipment.

BTW, I just got a Fluke 27/FM and it is an incredible piece of gear that I suspect would survive a nuclear blast.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 28, 2017, 07:59:18 pm
BTW, I just got a Fluke 27/FM and it is an incredible piece of gear that I suspect would survive a nuclear blast.

 ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on February 28, 2017, 08:55:10 pm
My go to "SAFE" meter is the EEVBlog BM235, but just to have a little home meter, I just bought the KASUNTEST ZT102, Amazon Prime, delivered for $20. I saw it on EBay for $16, but waiting 2-3 weeks from China with return hassles, made it silly to go that route. As you all know these are rebranded under other names. The EBay site was however informative, in that there are 3 models, one is a 2000 count, not many features, another one has NO temp option, in that switch position is just a 2nd "off" setting. The 3rd one is actually the ZT102, as it shows the temp option on the dial.

If I'm lucky enough to find a replacement fuse, I hope it's not 50% of the cost of the meter. :) Almost disposable at this price.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 28, 2017, 11:29:55 pm
My go to "SAFE" meter is the EEVBlog BM235, but just to have a little home meter, I just bought the KASUNTEST ZT102, Amazon Prime, delivered for $20. I saw it on EBay for $16, but waiting 2-3 weeks from China with return hassles, made it silly to go that route. As you all know these are rebranded under other names. The EBay site was however informative, in that there are 3 models, one is a 2000 count, not many features, another one has NO temp option, in that switch position is just a 2nd "off" setting. The 3rd one is actually the ZT102, as it shows the temp option on the dial.

If I'm lucky enough to find a replacement fuse, I hope it's not 50% of the cost of the meter. :) Almost disposable at this price.

I have the KT6666 on order as well.  My plan is to run the 102 first.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 02, 2017, 06:28:20 pm
They both made it in. 

Sharing the current input is never a good idea. I don't think any meter has survived where the designers have done this.  Does anyone think this meter will survive the new ESD test?   
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on March 02, 2017, 07:04:29 pm
My ZT102 came as well, I have to go pick it up locally. All I can do here is compare it to my BM235. Since I most likely will never use it for current measurements, at least I won't have to waste time looking for replacement fuses! :) For $20 delivered I figured why not, I'm sure it will be better for little home measurements then the old clamshell RadioShack pocket meters.

As far as your question:

I'm going to say it's going to FAIL your ESD test, not that I'm rooting for that outcome. As always I look forward to your video!
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on March 02, 2017, 07:58:56 pm
Interesting '101' copy.  There are several re-brands with teardown videos on youtube and the creepages are again too narrow at the inputs, so its unlikely to meet it CAT III 600V rating  :o.  My guess it will arc somewhere at the arrows, as you apply the pulse to each input. 

They both made it in. 

Sharing the current input is never a good idea. I don't think any meter has survived where the designers have done this.  Does anyone think this meter will survive the new ESD test?   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2017, 01:32:45 am
Anyone trace it out?  Looking at the pictures, just the one PTC and what looks like a transistor clamp.   Ditch the 10A and mA.  Leave the mV DC, temp and backlight.  Leave the crappy switch.  Add a few parts and make the thing survive. 

Caught some of Dave's live show tonight and is sounds like he is suggesting that the 121GW will not be as robust as the 235 because of the size.  I'm sure it will be better than my sponge prototypes.   With my tests not putting out much energy, it may do better than he expects. 
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on March 03, 2017, 01:47:23 am
How can Dave rightly call it the "121GW" unless it would survive a 1.21GW burst of electricity?    :D


(Sent with Tapatalk, so apologies for the lackluster formatting)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2017, 11:53:26 pm
How can Dave rightly call it the "121GW" unless it would survive a 1.21GW burst of electricity?    :D


(Sent with Tapatalk, so apologies for the lackluster formatting)

 :-DD :-DD

Right, Fluke 101 or the 121GW, which would Doc use?   :-DD   The name does seem to make you think it would survive a pretty big hit. 

Title: Re: Handheld meter electrical robustness testing.
Post by: zaoka on March 04, 2017, 05:12:17 pm
Would be nice to test new Metrix line... http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html (http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html)

Nobody tested these yet?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 04, 2017, 09:45:34 pm
Would be nice to test new Metrix line... http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html (http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html)

Nobody tested these yet?

I assume with the cost, it puts it out of the range of what most hobbyists would spend.  They may buy a more common like Fluke or Gossen.  Maybe TE will send one to Dave for a review.   
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on March 05, 2017, 02:54:54 am
Would be nice to test new Metrix line... http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html (http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html)

Nobody tested these yet?

I assume with the cost, it puts it out of the range of what most hobbyists would spend.  They may buy a more common like Fluke or Gossen.  Maybe TE will send one to Dave for a review.   

Are you still planning to run the ESD tests on the ZT102?
Thanks!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 05, 2017, 03:06:37 am
Would be nice to test new Metrix line... http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html (http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html)

Nobody tested these yet?

I assume with the cost, it puts it out of the range of what most hobbyists would spend.  They may buy a more common like Fluke or Gossen.  Maybe TE will send one to Dave for a review.   

Are you still planning to run the ESD tests on the ZT102?
Thanks!

I sometimes run the ESD before the AC line test.  Normally, the meters are subjected to all of the tests until they fail.  Since I started doing ESD testing, it looks like the only meter I did not test was the TPI 194II  and that was because it was damaged during the AC line test.   Interesting is someone posted a comment on YT about me not running that test on all the meters.  Strange. 

I finished running the ZT102.  It did not perform like I was expecting.   The video is going to have some extra bonus content in there as well.  I should have it edited and uploaded soon. 
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on March 05, 2017, 03:43:04 am
Would be nice to test new Metrix line... http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html (http://www.chauvin-arnoux.com/en/produit/mtx-3291.html?liste=/en/produits/31/98/multimeters/trms-digital-multimeters.html)

Nobody tested these yet?

I assume with the cost, it puts it out of the range of what most hobbyists would spend.  They may buy a more common like Fluke or Gossen.  Maybe TE will send one to Dave for a review.   

Are you still planning to run the ESD tests on the ZT102?
Thanks!

I sometimes with run the ESD before the AC line test.  Normally, the meters are subjected to all of the tests until they fail.  Since I started doing ESD testing, it looks like the only meter I did not test was the TPI 194II  and that was because it was damaged during the AC line test.   Interesting is someone posted a comment on YT about me not running that test on all the meters.  Strange. 

I finished running the ZT102.  It did not perform like I was expecting.   The video is going to have some extra bonus content in there as well.  I should have it edited and uploaded soon.

Thanks, the suspense is killing me! :)

The ZT102 seemed within spec, and close in basic home AC/DC and temp readings to my BM235, not using it to measure current. I did learn that unlike the BM235 you can use 1.8v Energizer lithium batteries to run it, get those cheap Chinese AAA leakers out of there! It's a bit flimsy feeling compared to the BM235, but at 1/6th the cost, I was not expecting much to begin with. While the LCD screen is not as good as the 235, it suffers from the disappearing characters when looking from a top down angle, the 235 screen suffers that as well, just not as badly.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 05, 2017, 06:24:19 pm
I'm finished with editing and it's uploading while I post.   

For me personally, I would take the BM235 over the ZT102/AN8002 for basic electrical work any day.  Sure, it costs a little more but its also certified and is a lot more robust.   If I needed a pocket meter for light electrical work,  I would still go with the 101.  I have no need for current or the TRMS feature and I am not at all a fan of having a shared current input.  I would rather have the robustness the 101 offers.   

For the bench, I'll stick with the Brymen BM869s for now.  It's not as robust as some of the meters I have looked at but it has many features that I tend to use.  I think my next pick would be that CEM DT9939 that Ruby sold for $120.  That was a deal.  Again, not a super robust meter, lots of drift with temperature but hard to beat that price with the features.   

If the UNI-T UT181A had been more robust (electrically and mechanically) along with addressing the other concerns I have with it, it would be a very nice meter.  As it comes from the factory, I'm not impressed with it but I feel it's better than the TPI 194II was. Now that was an over priced princess.

https://www.youtube.com/watch?v=HrcxnbkkhYg&feature=youtu.be (https://www.youtube.com/watch?v=HrcxnbkkhYg&feature=youtu.be)
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on March 05, 2017, 09:35:13 pm
I'm finished with editing and it's uploading while I post.   

For me personally, I would take the BM235 over the ZT102/AN8002 for basic electrical work any day.  Sure, it costs a little more but its also certified and is a lot more robust.   If I needed a pocket meter for light electrical work,  I would still go with the 101.  I have no need for current or the TRMS feature and I am not at all a fan of having a shared current input.  I would rather have the robustness the 101 offers.   

For the bench, I'll stick with the Brymen BM869s for now.  It's not as robust as some of the meters I have looked at but it has many features that I tend to use.  I think my next pick would be that CEM DT9939 that Ruby sold for $120.  That was a deal.  Again, not a super robust meter, lots of drift with temperature but hard to beat that price with the features.   

If the UNI-T UT181A had been more robust (electrically and mechanically) along with addressing the other concerns I have with it, it would be a very nice meter.  As it comes from the factory, I'm not impressed with it but I feel it's better than the TPI 194II was. Now that was an over priced princess.

https://www.youtube.com/watch?v=HrcxnbkkhYg&feature=youtu.be (https://www.youtube.com/watch?v=HrcxnbkkhYg&feature=youtu.be)

I haven't seen that screw driver tester in 30 years, nice find.

Awesome test! You made the ZT102 hop, skip, and then turn into a 4th of July fireworks display! Excellent SLOW MO shot.
I didn't think it would get as far as it did. I'm still interested in the Woods meter, just to have in my travel bag, but again was surprised the ZT102 did better overall in robust tests, perhaps the UL listing makes the Woods cost more?

Do you think the ZT102 would pass tests for a UL listing?

Thanks for testing the fuse as well, since I'll never use the ZT for current, good to know if I blow the fuse, it will still work in the other modes, can't thank you enough for revealing that! I'm tired of tracking down oddball replacement fuses.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 06, 2017, 01:31:27 pm
I didn't think it would get as far as it did. I'm still interested in the Woods meter, just to have in my travel bag, but again was surprised the ZT102 did better overall in robust tests, perhaps the UL listing makes the Woods cost more?

Do you think the ZT102 would pass tests for a UL listing?

Thanks for testing the fuse as well, since I'll never use the ZT for current, good to know if I blow the fuse, it will still work in the other modes, can't thank you enough for revealing that! I'm tired of tracking down oddball replacement fuses.

Having any product certified will cost money.  Going for both the safety as well as EMC will cost even more.  And if you don't do your job as a designer, it's not like UL will give you a free pass if your product fails.  You pay again.  This is why most will test their products during the development cycle rather than waiting until the last minute.  And sure, that cost is going to be added on.

I really have no idea if the ZT102 would pass the safety standards or not.  I am not even sure what it means to pass.  I'll leave that to the experts to sort out.   

One thing I can tell you, like I mentioned in the video, I have exposed that Fluke 101 to all the transients I have shown (except the highest level that eventually damaged 5KY's Fluke 107)  and you have never seen sparks or flames emit from it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 06, 2017, 04:28:26 pm
Not a bad little meter for low voltage hobby use.

(I think it needs uA though)

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 06, 2017, 05:47:34 pm
I haven't seen that screw driver tester in 30 years, nice find.

Am I the only person still using one of these? :popcorn:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=297085;image)

(just kidding, I'm not really... I remember using on in my youth though)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 06, 2017, 06:50:41 pm
I haven't seen that screw driver tester in 30 years, nice find.

Am I the only person still using one of these? :popcorn:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=297085;image)

(just kidding, I'm not really... I remember using on in my youth though)


I like some of John Wards videos.  This one seems to have struck a nerve.  He may have my first video showing the UT139C getting damaged beat.   :-DD :-DD   Funny thing about that video is add a little review to it, then watch it die at the same level then it's ok.   :-DD

https://www.youtube.com/watch?v=wLAJ-keFmpk (https://www.youtube.com/watch?v=wLAJ-keFmpk)

I wish Photonicinduction were creating content again.  I really enjoyed following him. 
https://www.youtube.com/watch?v=AGXQNLq19FQ (https://www.youtube.com/watch?v=AGXQNLq19FQ)


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2017, 02:55:35 am
The spreadsheet has been updated to include the ZT102.  I also took out the KT6000 also known as the AN860B and took the continuity data for it.  This is included in the spreadsheet as well.   Watched a couple of videos on it.   

His freq test shows it is much worse than the ZT102.  That thing had no problems at 200MHz.   


https://www.youtube.com/watch?v=92Asdrcb_DE&t=19s (https://www.youtube.com/watch?v=92Asdrcb_DE&t=19s)

https://www.youtube.com/watch?v=ZPS_MCUFnjM (https://www.youtube.com/watch?v=ZPS_MCUFnjM)
Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 08, 2017, 04:11:51 am
Not a bad little meter for low voltage hobby use.

(I think it needs uA though)

The Zotek ZT98/Aneng AN8004 has the microamp setting.   Why not get one of each. :)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 08, 2017, 09:53:34 am
The Zotek ZT98/Aneng AN8004 has the microamp setting.   Why not get one of each. :)

http://www.ebay.com/itm/172513539473 (http://www.ebay.com/itm/172513539473)

So it does... and cheaper, too!

But no capacitance or temperature - you can't win.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2017, 12:45:41 pm
The KT6000 is TRMS, has temp, uA, a relative mode and the current inputs are not shared.   They claim CAT IV 600V.  Has 250V glass fuses and one vary small PTC and two transistors for the input protection.  Lots of room inside.
Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 08, 2017, 03:48:15 pm
So it does... and cheaper, too!

But no capacitance or temperature - you can't win.

I won't even mention that the cheaper sibling is only 2000 count.   Still I got one of each on order for the price....as well as a Aneng ANG860B+ (Zoltek ZT17B+/Kasuntest 6000).   Based on some review videos the frequency and measurements on the smaller meters are better but the larger has a few more features (min/max - manual ranging) that might come in handy.   Plus I can't wait to test out some 20A circuits with it!  :bullshit:

I also noticed that while the meters seem to be identical on the outside, they tend to sell in different price ranges...

Aneng (Cheapest) http://www.ebay.com/itm/ANG860B-Digital-Multimeter-Backlight-Auto-Ammeter-Voltmeter-Ohm-Portable-Meter-/282298159352?hash=item41ba4810f8:g:acIAAOSwux5YWaCU (http://www.ebay.com/itm/ANG860B-Digital-Multimeter-Backlight-Auto-Ammeter-Voltmeter-Ohm-Portable-Meter-/282298159352?hash=item41ba4810f8:g:acIAAOSwux5YWaCU)
Zoltek (More Expensive) http://www.ebay.com/itm/ZOTEK-VC17B-Auto-Manual-Ranging-LCD-Display-Multimeter-with-Thermocouple-/282371228533?hash=item41bea30375:g:e1QAAOSwB-1Yps2g (http://www.ebay.com/itm/ZOTEK-VC17B-Auto-Manual-Ranging-LCD-Display-Multimeter-with-Thermocouple-/282371228533?hash=item41bea30375:g:e1QAAOSwB-1Yps2g)
Kasuntest (Most Expensive) http://www.ebay.com/itm/KASUNTEST-6000-Counts-TRMS-Auto-Ranging-Digital-Multimeter-with-Capacitance-Hz-/282318275160?hash=item41bb7b0258:g:bOMAAOSwUKxYcR1~ (http://www.ebay.com/itm/KASUNTEST-6000-Counts-TRMS-Auto-Ranging-Digital-Multimeter-with-Capacitance-Hz-/282318275160?hash=item41bb7b0258:g:bOMAAOSwUKxYcR1~)

which makes me wonder if there are any internal differences - I can't imagine the probes being that much of a differentiator...
Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 09, 2017, 02:50:50 pm
The KT6000 is TRMS, has temp, uA, a relative mode and the current inputs are not shared.   They claim CAT IV 600V.  Has 250V glass fuses and one vary small PTC and two transistors for the input protection.  Lots of room inside.

I received the Aneng version of the KT6000 yesterday and played with it for a bit and was quite impressed feature-wise.  I can see this replacing the 17B+ for my microcontroller testing work which has been a bit of a let down.  The continuity seems as good as on the ZT102 (and dare I say some high end flukes) and it has the micro-amp setting.  It measured a 1pF capacitor (at 3pF with the leads RELed out vs 1.7pf on Peak Atlas LCR) and a 10000uF capacitor (took close to 10 seconds to get to Mf range, but it DID show a fairly accurate value).  It would light LEDs (Red - White) with displayed voltage and test Zener diodes up to around 3V.  Measured 10MOhm resistor and 1.2 within specs.

Thanks for blowing up all these meters in the name of science, Joe. - Can't wait for the robustness testing on the KT6000 and still waiting for the ZT102 based meter to arrive via slow boat.






Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2017, 11:34:21 pm
3pf?! Wow! Have you tried running it up to 20A? Have you checked to see if yours would measure higher than 8MHz.   

I have not done anything with mine yet.  Maybe this weekend.  If you run into a problem with yours and want me to try something, just ask.  Rare these meters survive my reviews.... 
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on March 11, 2017, 12:37:05 am
Thanks for blowing up all these meters in the name of science, Joe. - Can't wait for the robustness testing on the KT6000 and still waiting for the ZT102 based meter to arrive via slow boat.

@joeqsmith, I think you should put "blowing up meters in the name of science" in your signature.   ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 11, 2017, 01:05:19 am
I was just kidding about doing a 20A test with it.  I don't have the Lexan-protected safe box to do testing like you do...I'll probably keep this meter in a mA ranges max.

As for frequency at 500mV, 1V and 5V the best I could do stably was 10MHz.   After that is sometimes would show the higher frequency briefly before going to all 0's - up to 20MHz then, nothing.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 11, 2017, 01:59:15 am
I was just kidding about doing a 20A test with it.  I don't have the Lexan-protected safe box to do testing like you do...I'll probably keep this meter in a mA ranges max.

Too late to back out now.  >:D

Direct Current
20A +/-1.5%+3, res 10mA
Max measuring voltage drop: measuring range 20A is 200mV
Max input current: 20A (no more than 10 seconds)
Overload protection: 20A/250V fuse

For AC, is basically the same except
Max input current: 10A (no more than 15 seconds)

Think that's a 20A 250V glass fuse in there?  I don't have another meter that claims 20A and my bench supply is good for 6A.   

But I think I can get us a constant 20A and the Brymen can read 20A with a pretty low drop.  Wonder what current that little baby shunt will open up at.  :-//

As for frequency at 500mV, 1V and 5V the best I could do stably was 10MHz.   After that is sometimes would show the higher frequency briefly before going to all 0's - up to 20MHz then, nothing.

The manual has a CAUTION about auto range only in frequency mode.   I wonder if they won't switch to the low range.  Did you try both the mv and volts functions?  Same results?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 11, 2017, 02:01:44 am
I wonder if there is something that could be adjusted to get it to read higher than 10MHz.   Pretty sad after seeing that pocket meter up at 200MHz.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 11, 2017, 02:09:18 am
" I don't understand why this guy damages all multimeters?!?"
 :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on March 11, 2017, 02:28:02 am
" I don't understand why this guy damages all multimeters?!?"
 :-DD

And .... we just love ya for doing it!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 11, 2017, 02:42:14 am
" I don't understand why this guy damages all multimeters?!?"
 :-DD

And .... we just love ya for doing it!
:-DD

Brymen with my 1mV/A shunt and KT6000 direct.  No doubt the Brymen and shunt will take 20A.  I wonder about the leads they supply with this thing.  Maybe I should include them when I run it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 11, 2017, 02:51:10 am
Quote
Ig Saturation   5 days ago   
Excellent as always Joe.  It blew close to where I thought it would, and the arc energy atomized the tracings with it.  You could get another blast off that meter by doing the 10A input.

It does appear the 10A circuit survived.  We can't have that.   Time to get the window fan out....
Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 11, 2017, 05:47:26 am
The manual has a CAUTION about auto range only in frequency mode.   I wonder if they won't switch to the low range.  Did you try both the mv and volts functions?  Same results?

With V setting, I can get 100KHz at 20V (the V max on the Func Gen) or 80KHz at 5V.   Much worse than with mV

1Hz seems to be the bottom of the range on both V an mV.   

I couldn't find any way to turn off AUTO mode for frequency.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 12, 2017, 12:57:48 am
It won't be long now....  Can it out survive Fluke's golden standard 87V...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 12, 2017, 09:30:08 pm
The spreadsheet and video for the KT6000 have been uploaded.

https://www.youtube.com/watch?v=4PjmFqzlfLc (https://www.youtube.com/watch?v=4PjmFqzlfLc)

Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 12, 2017, 09:59:30 pm
One thing I noticed was that the Duty Cycle % go way off as you increase past 100KHz.  Both sine and square waves were spot on to 100KHz then started drifting.   I'll take some measurements later tonight and post what I mean.  I think it just means that the 100KHz is the ceiling for accuracy across frequency.  Ironically, its where a couple of the Fluke meters cap frequency at...

Also, my meter exhibits the same issue going from AC-DC-AC where it under-reads after going back to AC.  It has shown similar behavior when switching between modes like resistance and capacitance.  I've found myself going to off first when switching modes which is totally not cool.
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on March 12, 2017, 10:37:23 pm
The spreadsheet and video for the KT6000 have been uploaded.

https://www.youtube.com/watch?v=4PjmFqzlfLc (https://www.youtube.com/watch?v=4PjmFqzlfLc)

FIRE & SMOKE reward when you get to the end of the video, NICE!
Some manual spec busting too.

If I'm interpreting this video and the ZT-102 video, correctly, while lacking some of the extra features, it seems the ZT-102 is overall more robust, correct?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 13, 2017, 01:40:08 am
FIRE & SMOKE reward when you get to the end of the video, NICE!
Some manual spec busting too.

If I'm interpreting this video and the ZT-102 video, correctly, while lacking some of the extra features, it seems the ZT-102 is overall more robust, correct?

The ZT102 was damaged at 3KV.  The KT6000 was damaged at 4KV.  So no, I would not interpret the ZT102 as being more robust. 

Your interpretation may only consider the voltage modes of the two meters where I am looking for any electrical failure. 

The two Fluke videos I linked of the 87V are interesting as they don't functional test the meter between levels and they only test the one mode.  Can the 87V really survive the levels they show in during the video, clearly it depends on the test procedure.  It did very poorly in my testing because I look at all the modes and test the meters between each level.   

The Hioki was a rare exception where electrically the meter was not damaged but the plastic was starting to melt.  The meter could have done much better in the tests had the plastic insert been extended.  So I made a note of it and moved on. 

It is because of these details that I leave the videos on-line.  If someone has a question about what was done, or how a meter failed, they just need to watch the video.
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 13, 2017, 03:15:50 am
These ZT/KT meter versions are rather afforable.
As a spare meter for electrical/car wirk it would either be one of these, or the more expensive am-510a.
Anyone tried the AM-500A?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 13, 2017, 11:03:10 pm
These ZT/KT meter versions are rather afforable.
As a spare meter for electrical/car wirk it would either be one of these, or the more expensive am-510a.
Anyone tried the AM-500A?

Yes, you can save a lot of money on a product by not having them certified, use glass in place of HRC fuses, use stamped connectors, leave out MOVs, don't test your software, used a single LED for your back light....  It all adds up. 

The HF free meters are very affordable as well. For garage work, why not.  Of course the new ones you can't replace the fuse, there is no back light, no beeper.....    But they are inexpensive.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 13, 2017, 11:38:02 pm
The KT6000 shunt was pretty small.  Here are the ones I had saved.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 15, 2017, 11:06:04 pm
Wow, we broke 2000 followers.  Dave mentioned that the GW121 may be a while yet.  Seems I have seen that post before so starting to look at the runner up in the poll, Gossen.  I think unlike what I did with Keysight where I bought a lower cost meter to run, I would like to buy something that I would actually want to use. 

In the mean time, I had thought about making a video just about the shunts I had saved.  Maybe take some dimensions, make some calculations and then run them.  I bet Watt loading on some of them is really bad.  And who knows what material they use.  TCs may be all over the place.  Take them to failure like I did with the meter test leads and see what we can learn from it. 

If you have any thoughts on running them, feel free to chime in. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 16, 2017, 05:50:02 am
I look forward to the shunt shootout. Your tests look reasonable. The TC might be difficult, but it was something I have long been pondering.
That RS meter shunt looks massive, when compared to the others.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 16, 2017, 05:03:28 pm
That RS shunt is by far the largest I have seen in a handheld.  I think this video is going to be a David vs Goliath story except David looses big time.    :-DD

Metrahit looks interesting...
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 16, 2017, 08:27:28 pm
That RS shunt is by far the largest I have seen in a handheld.  I think this video is going to be a David vs Goliath story except David looses big time.    :-DD

Metrahit looks interesting...
It looks like it will go this way.
RS-760H/mm2000/UT61E....ZT102
This will be interesting. That ZT shunt might be good for a watt. If you measure the size/resistance, you can do some ebay shopping.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 17, 2017, 02:48:52 am
The videos close to 30 minutes so far and I still have not damaged a shunt but not to worry..  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 17, 2017, 11:28:17 pm
Watched Dave's reviews of the Gossen power meter.  :--  No way I would spend over $1000 on a meter with a tacked on resistor.  Too bad, like some of the features.  Review was not too great.  Hardly turned the thing on.   

Looked at various pictures of the internals of other Gossen products.  Some look like they were made in the 90's. 

Now looking at the lower end Extra.  From the manual, they mention the KS30 for additional protection.  Search their site, nothing.   I would like to get the KS30 with it if I go this route but can't find anyone who carries it.   Time to send them an email.   

Quote
The multimeters are protected against transient overvoltages of
up to 8 kV with wave-front durations of 1.2 ms and halftimes of
50 ?s in the voltage measuring range. If longer pulse durations are
expected, for example when conducting measurements at transformers
or motors, we recommend the use of our KS30 measuring
adapter. It provides protection against transient
overvoltages of up to 6 kV with wave-front durations of 10, and
halftimes of 1000 ?s.
Continuous load capacity is 1200 VRMS. Additional influence error
caused by the KS30 measuring adapter amounts to approximately
-2%.
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 19, 2017, 04:40:03 am
The shunt testing is finished.  Was going to test the shunt out of the 121GW but the foam would not conduct.  And I thought it was the lowest burden meter out there.

Video should be up in the today sometime. (lack of sleep)
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 19, 2017, 05:06:20 am
The shunt testing is finished.  Was going to test the shunt out of the 121GW but the foam would not conduct.  And I thought it was the lowest burden meter out there.

Video should be up in the today sometime.
I'll be looking forward to it. I saw your post, and expected to see a video.
Is is just me, or do some of those shunts look different... :-BROKE >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 19, 2017, 12:19:22 pm
Warning, its long.  12 shunts X 5 seconds per Ampere X (100A - 3A).  Even speeding this up, it's still about 45 minutes.  I ran some checks using nichrome wire as well. 

https://www.youtube.com/watch?v=ne4Ls2mPF-s (https://www.youtube.com/watch?v=ne4Ls2mPF-s)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 19, 2017, 07:57:56 pm
If all of the shunts were identical, there are still some errors in the setup.  Sensing the voltage near the supply for example adds some error, it will not vary like the temperature sensor placement or the biggest problem, inserting the shunts into the clamps. 

To give you some idea of the variance of the jig, here is the plots showing the resistance across the entire 100 Ampere sweep for all of the 5mohm shunts.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 19, 2017, 08:12:53 pm
Two of these shunts were from CEM branded meters.  They appear to have the same diameter and length so we expect these two will behave the same.   Only looking at these two, the first graph shows their resistance.  The next plot shows their voltage drop.  These two were very linear across the entire 100A sweep.   The temperatures were within 70deg C which is better than I would expect as there is a large temperature gradient across the surface.  Those clamps are a plated brass with lots of thermal mass. 

One thing I wish I had explained was Watt density.  We are looking at the power dissipated with how much surface area the part has.  The Kunsuntest ZT102 and free HF meter both calculated out to 12W/in^2.  The nichrome with even higher resistance really pushes this up and why it makes good toasters and hair dryers. Lots of heat in a very small space.. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 19, 2017, 08:16:15 pm
For the few people that are interested, I have attached the raw data I collected during these tests.   Voltage, current, power and temperature.  One file for each shunt tested. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 19, 2017, 08:19:52 pm
I look forward to watching the video. Unfortunately at the earliest it will be Monday, or Tuesday night.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 19, 2017, 08:30:30 pm
In no way have I seen the insides of as many DMM's as Joe but in cheaper ones the shunts seem to be made of copper or brass.  :--
Unless they're made of materials accepted for shunts like Constantan, no wonder there's some variability.  ::)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 19, 2017, 08:49:36 pm
In no way have I seen the insides of as many DMM's as Joe but in cheaper ones the shunts seem to be made of copper or brass.  :--
Unless they're made of materials accepted for shunts like Constantan, no wonder there's some variability.  ::)

Manganin is made up of about 86% copper, 12% manganese and nickel, so yes they do look like copper.   Constantan has about 55% copper and nickel.   

https://books.google.com/books?id=sxkPJzmkhnUC&pg=PA158&lpg=PA158&dq=constantan+or+manganin&source=bl&ots=AJxv8bmzp-&sig=0FcOzbS9QGymOEuqr71AYjH5p8M&hl=en&sa=X&ved=0ahUKEwi_0uqOuOPSAhWm7YMKHcPjCREQ6AEIajAL (https://books.google.com/books?id=sxkPJzmkhnUC&pg=PA158&lpg=PA158&dq=constantan+or+manganin&source=bl&ots=AJxv8bmzp-&sig=0FcOzbS9QGymOEuqr71AYjH5p8M&hl=en&sa=X&ved=0ahUKEwi_0uqOuOPSAhWm7YMKHcPjCREQ6AEIajAL)
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 20, 2017, 06:36:21 am
Nice job, I enjoyed it.
What was the software you were using?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 20, 2017, 10:34:15 am
Nice job, I enjoyed it.
What was the software you were using?
I use LabVIEW.

Voltage drop measures at 10.00 Amperes

Using large body HRC fuses
Brymen, BM869s, 312mV
UNI-T, UT61E, 239mV, Modified 
CEM, DT9939, 350mV
UNI-T, UT181A, 294mV
Fluke, 115, 280mV
AMPROBE, AM530, 353mV
Fluke, 107, 325mV
Other...
Cen-Tech, 98025, 131mV, No fuse
External Shunt, 10mV

I made one more attempt to further improve the UT61E by adding even more copper and reduced it another 20mV was all. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 20, 2017, 06:39:55 pm
Joe, one more excellent video. Thank you for the work.

I think that Centech will start stamping their meters with "exclusive 100A fuse" in the 10A input. That or the input will actually be marked as 100A (20 sec max).  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on March 20, 2017, 09:48:24 pm
LOL, yeah. Instant upgrade of fuse and higher current rating. Weee!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 20, 2017, 11:33:28 pm
Voltage drop of the meter test leads swept from 2 to 20 Amperes in 2A increments.   One meter stands alone....     
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 21, 2017, 12:13:48 am
Is that Centech yellow/green?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 21, 2017, 02:46:42 am
Is that Centech yellow/green?

You bet it is.  They could make the meter with 100A for a 20 seconds and if the shunt doesn't melt off the board, the leads would open.   

I wonder how the probes included with the two Kasuntest meters would do.  Better yet, I wonder what leads the 121GW will include.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 21, 2017, 03:37:38 am
You bet it is.  They could make the meter with 100A for a 20 seconds and if the shunt doesn't melt off the board, the leads would open.   

I wonder how the probes included with the two Kasuntest meters would do.  Better yet, I wonder what leads the 121GW will include.   
You should have filmed that.
on the 1.21GW That will be a good guess.
I have a pair of Probemasters on my 87-1, and a set of modified(cut off safety shroud) gold Brymen's on the 3456A, with a set of Fluke probes floating around. My biggest problem with the HF meter, is that the probes are too short :( .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 22, 2017, 12:12:37 am
He mentioned they would start testing in January but I guess that was pushed out.  Better to make sure they are happy with it before it gets released. 

I did capture the lead tests.  Here is the free cen-tech meter leads.   
https://youtu.be/fQowDZstguw?t=1222
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 01:55:50 am
The UT61E, a real 20A meter.   

Some calculations,  fuse & Manganin sheet stock
https://www.digikey.com/product-detail/en/schurter-inc/0090.0020/486-2707-ND/2644881 (https://www.digikey.com/product-detail/en/schurter-inc/0090.0020/486-2707-ND/2644881)


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 01:57:27 am
Current through the shunt, voltage across the shunt and calculated resistance compared with the original shunt.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 01:59:19 am
Much lower Watt density.    Note also the added copper in the terminals. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 02:00:59 am
Checking alignment against the Brymen BM869s.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 02:09:22 am
A nice and toasty meter.  Brymen looking at the drop across the modified UT61E.  The UT61E will over range a bit over 22 Amperes. 

Does it reach 200mV at 20A like their claim in the Kasuntest manual, no.  The fuse and shunt get pretty warm with 10W but I ran it like this for a five minutes with no problems.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 11:43:04 am
The Kasuntest KT6000 at 22A.  2 more Watts.
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on March 24, 2017, 04:07:00 pm
Where did you get the manganin sheet from?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 04:21:54 pm
Watched Dave's reviews of the Gossen power meter.  :--  No way I would spend over $1000 on a meter with a tacked on resistor.  Too bad, like some of the features.  Review was not too great.  Hardly turned the thing on.   

Looked at various pictures of the internals of other Gossen products.  Some look like they were made in the 90's. 

Now looking at the lower end Extra.  From the manual, they mention the KS30 for additional protection.  Search their site, nothing.   I would like to get the KS30 with it if I go this route but can't find anyone who carries it.   Time to send them an email.   

Quote
The multimeters are protected against transient overvoltages of
up to 8 kV with wave-front durations of 1.2 ms and halftimes of
50 ?s in the voltage measuring range. If longer pulse durations are
expected, for example when conducting measurements at transformers
or motors, we recommend the use of our KS30 measuring
adapter. It provides protection against transient
overvoltages of up to 6 kV with wave-front durations of 10, and
halftimes of 1000 ?s.
Continuous load capacity is 1200 VRMS. Additional influence error
caused by the KS30 measuring adapter amounts to approximately
-2%.



Their response below. 

Quote
Daer Joe,

Thank you for your Email.

I just checked the article KS30 and it was discontinued several years ago.

This was a mistake in our manual and we will correct it asap.

If you require a quotation for M250A you can contact our US subsidiary:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2017, 04:24:52 pm
Where did you get the manganin sheet from?

Came from a friend of mine.  Looks like you can order wire or sheet stock of pretty much any size.   I plan to make a video of the 61E but am still waiting on the proper fuses.  This is were a lot of the heat is going now.  Old 15A Fluke fuse, surprised it survived over 20A. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 26, 2017, 03:29:06 pm
Measuring 20A with the UT61E.  This meter is starting to look as bad as my UT90A.   

https://www.youtube.com/watch?v=RRhFYERTSxY (https://www.youtube.com/watch?v=RRhFYERTSxY)
Title: Re: Handheld meter electrical robustness testing.
Post by: oh2hyt on March 29, 2017, 06:22:12 am
I read whole thread last week. And originally youtube suggested your videos to me.

Nice work, keep going - without pressure.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 29, 2017, 11:15:00 am
Thanks and glad you are enjoying them.

YouTube gives you all sorts of metrics.  One is the source of the traffic.  By far the highest is YouTube recommended which is about 40%.  YouTube search is very high as well.  External is about 6%, of which Google search makes up about 40% and  EEVBLOG is about 6%.   A little strange as this thread is really about the only place I post about it.   

If 60 minutes of talking about wire was not enough, someone had asked me about the shunts having an offset after they were heated.  In the last video, I never let the meter cool enough which may have led to some confusion.  I was planning a very quick video on this as time permits.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2017, 02:33:44 am
Using my MIG welder on the UNI-T UT61E.    :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2017, 03:09:47 am
Using the oxy acetylene torch on my UT61E.  Time to machine up some parts.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2017, 04:47:38 am
Enjoy

https://www.youtube.com/watch?v=ns02v6ebCGU (https://www.youtube.com/watch?v=ns02v6ebCGU)
Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on March 31, 2017, 01:45:12 pm
So, Joe, has anyone from UNI-T contacted you for a place on the engineering team?   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2017, 11:08:10 pm
So, Joe, has anyone from UNI-T contacted you for a place on the engineering team?

Now that would be funny.  Actually, no one from any company (manufacturer,  designer or distributor) has ever contacted me about any of my multimeter videos beyond the few responses I have received to questions I have asked. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 01, 2017, 07:56:32 pm
Looking at some of the meters burden voltage in the 1uA range.

https://www.youtube.com/watch?v=7ivcPLOOACg&feature=youtu.be (https://www.youtube.com/watch?v=7ivcPLOOACg&feature=youtu.be)
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on April 02, 2017, 10:22:22 am
Know that the new EEvblog meter will be given a very thorough test in that lab. I think though that those shunts might be a hard thing to make in bulk cheaply, unless you made a custom machine that took a precut length of material, used a welder to do an automated join both sides to a solderable material, then finished the join to an acceptable dimension, and then bent it appropriately, followed by another jig that allowed automatic grinding up to the required value. following that a journey through a polishing machine to get them shiny again and then installed.

Do like that PTFE housing there, very nice looking, and probably costs as much as the BOM of the meter alone.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 02, 2017, 02:15:38 pm
I used silver solder with a torch.  The two ends I machined from brass.  I do use a lot of Teflon in my projects.   

Want to talk about cost, what's fully burdened engineering time cost now days?  Spread that across one meter....  This one UT61E is a goldmine!  :-DD  IMO, it's a better meter functionally now but it's still poor.  That 1K shunt could be improved and still no temperature and no AC+DC and.....  It's a very poor investment from cost standpoint but for the few people who watch my videos, it may be worth it in entertainment.     

I have had a few people post about making a kit, to me its a really bad idea but sounds like that would be something you may be interested in pursing. Drop some Evanohm in there.
 
http://www.goodfellow.com/catalogue/GFCat4J.php?ewd_token=M5lGZEHfcEMRY5GH6lqFqvdENYjdCH&n=owTbQj1aBHgd3f2gHi6hCcK12EZeOa (http://www.goodfellow.com/catalogue/GFCat4J.php?ewd_token=M5lGZEHfcEMRY5GH6lqFqvdENYjdCH&n=owTbQj1aBHgd3f2gHi6hCcK12EZeOa)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 02, 2017, 04:52:50 pm
The remainder of the meters I have that support the uA range are checked.  Also someone had asked about running them at a higher current.   I also tossed in the Fluke 101 because everyone knows it can't read current. 

https://www.youtube.com/watch?v=RMI68kXJNCo (https://www.youtube.com/watch?v=RMI68kXJNCo)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 08, 2017, 09:29:55 pm
The TPI looking at the drop across the UT181A, the Brymen looking at the drop of the UT61ELB.   Hope to have the video on-line in a few hours.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 08, 2017, 10:30:51 pm
Enjoy

https://www.youtube.com/watch?v=14eHpHQxm54 (https://www.youtube.com/watch?v=14eHpHQxm54)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 16, 2017, 05:57:28 pm
I still have not pulled the trigger on a Gossen to run.  These are the three I am considering for my 2000 follower review.  Functionally none of them are as good a fit for me as the Brymen BM869s or the UNI-T UT181A.     

M205A $243, 6000 count, basic meter
If I go this route, it’s like buying the low end HIOKI just to see how they do.   
http://www.tequipment.net/Gossen-Metrawatt/M205A/Multimeters/?b=y&v=7758 (http://www.tequipment.net/Gossen-Metrawatt/M205A/Multimeters/?b=y&v=7758)
 
M248A, $732, 310000 count
It can’t measure conductance, can’t measure two temperature inputs, has no bar graph but they offer a BT version. 
http://www.tequipment.net/Gossen-Metrawatt/M248A/Multimeters/?search=true (http://www.tequipment.net/Gossen-Metrawatt/M248A/Multimeters/?search=true)

M249A, $1053, 60000 count
Measures conductance and it can measure power.  Dave did a review of it and it looked like shit on the inside.  Some tacked down axial resistor.  I was not impressed.   I asked Gossen if this was a production meter as they link Dave's video.  No response but Howardlong provided the information below. 

I am leaning towards the Ultra being a better fit and something I would actually use.  If you own one of the Ultra, I would be very interested in hearing how you like it.  Any problems? 

Gossen provides a link to your video and I asked them if the meter was a proto or if the tacked down resistor was current production.  I have not heard back.  Did you ever find out?

I guess it is no more and they had a re-spin, this is mine, purchased about 18 months ago.

Full 20MP Hi-res image here (https://pryxta.bn1303.livefilestore.com/y4pC4au-4M7lCipjwHUZ0xNlrwsyaYTkGHzy9AIhraCci74StpSfHeNlIaUThPurALi1Bs7W16RHV_5ntNdZtVTUwWLhDhz2LxdOQfSCz5nQGc5aLHO_SEbQ3xeF3Nbv_1LNbQDoQXOoTU7KtqKXgHwkG0Y2e6VHj0QCcSpE8TMs4r7EL0IdB9aEEJheILiPPb9/P1000081.JPG)

(https://www.eevblog.com/forum/supporters-lounge/the-eevblog-multimeter-prototype/?action=dlattach;attach=308420;image)


Thanks for the picture.  Looks good.  After 18 months, any complaints with it?  The only bad comment I have seen was on Dave's video where the person shorted the current inputs to the mains and damaged the meter.

I hardly ever use it. Being an Energy meter with simultaneous I and V, I bought it on the premise I'd be able to use it for measuring microcontroller power in and out of low power modes, but I'm afraid I've found it's useless for that. The relatively slow auto-ranging means the burden voltage changes so it has too much effect on the DUT. I really should've thought that through!

I am sure it's good for higher power simultaneous I and V.

The other thing is that there is a physical prevention of you having probes plugged in and/or moving the dial in certain modes with probes plugged in. I find it a bit of an irritation, a bit nanny state if you like, I'd rather it beeped at me instead.

The ground probe is stackable at the meter end which means it protrudes out. Now while a stackable probe is great in some circumstances, it means it won't fit into its purpose made case with it plugged in. I like to have a meter ready to go, probes connected, you can't do that with this meter if you use the carrying case.

I find using the meter itself a bit daunting, the UI isn't too obvious to me, I find I have to refer to the manual. This may also be down to lack of use though!

Despite being soft power on, the two AA cells are the same ones supplied with the meter 18+ months ago, so that works OK.

I would say that it does look the part when you get it out on the bench!

With apoogies, this is off topic.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 23, 2017, 12:50:36 am
I was looking to improve the burden voltage for the UT61E's mA ranges. 
https://www.youtube.com/watch?v=tgA6Ii_KAPs (https://www.youtube.com/watch?v=tgA6Ii_KAPs)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 25, 2017, 01:17:33 am
Painted the little PCB case I made for the powered shunt.  Used some rub on lettering.  Hit it with some of the wife's clear nail polish and things went to down hill.  I've letter like this countless times.  Maybe Revlon changed their formula.   :-DD   I didn't show it doing any AC like I did with the UT61E mods.  So here's a shot comparing it with the EEVBLOG BM235 meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on April 25, 2017, 02:22:42 am
Unfortunate situation with the lettering there. I've had clear nail polish dissolve cured paint before. Hard to know what to expect until the chemicals meet.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 25, 2017, 02:50:30 am
The last bottle my wife picked up for me was marked 3994 Clear 76. The contents are starting to get pretty thick and turning yellow (I had a VIC20 when she bought it).  It lists the contents on the bottle.  Females play with some pretty bad chemicals.   The new stuff was a 771 Clear and has a peal off sticker I just found on the underside listing the contents.  New formula. 

I used to just spray them with clear coat (enamel to match the paint) but like the nail polish for quick jobs.  Looks like it's back to enamel spray. 

I need to write Revlon a letter explaining I am a dissatisfied customer  :-DD :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on April 25, 2017, 04:49:10 am
I need to write Revlon a letter explaining I am a dissatisfied customer

That'd be a hoot :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 29, 2017, 02:24:31 am
SIBA branded fuses sold by UXCELL. 

https://www.youtube.com/watch?v=EWu8wMspROQ (https://www.youtube.com/watch?v=EWu8wMspROQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on April 29, 2017, 03:40:41 am
That was a nice video, thanks.
I have a set of those Cross pens/pencils.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on April 29, 2017, 04:32:59 am
SIBA branded fuses sold by UXCELL. 

I've always been leery of fuses from who-knows-where. Good to see some tests that quantify it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 29, 2017, 05:23:12 pm
Even if we ignore the whole safety side of it, it would be interesting to have a few meters that use this fuse and see if there are cases you could damage the meter with a counterfeit where it would have normally survived.  The problem with that is the counterfeit fuse supplier's may not have very good quality control (why would they?) and the trip time/current could vary a fair amount. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on April 30, 2017, 05:04:43 am
Yeah, you'd probably have to test a fair number of them to get any kind of statistical significance. Sounds expensive, but interesting. It would also be interesting to see how accurate, relative to their spec sheet, and consistent the genuine ones are.

One potentially good thing about the fake one you tested was the lower resistance.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 04, 2017, 02:45:19 am
There was a fairly good drop in the burden voltage on the UT61E when I changed to the 20A fuse.  But consider I had beefed up the shunt, connectors and surrounding traces to handle the additional current.   So I will give you that putting on of these counterfeits in say the UT61E's 500mA it would further improve the burden and I believe the diodes would handle the added current in that one case.  However they are not using 4000 series diodes and I have those large TVSs in there now.   I wouldn't attempt it on any meter I cared about without looking at the circuit to make sure it could handle it. 

A friend of mine gave me his old RadioShack meter today.  It's catalog number 22-813.   On the back it states "Custom manufactured in China for RadioShack Corporation".   This in one of those really bad designs where they share the V/ohms with the mA.  One wrong turn of the knob and at best you pop a fuse.  Worse, the mA is between the ohms and volts.   :palm:   Oh yea, it's also unfused for the 10A input.  I wonder if it's like that crappy Tekpower analog meter where the fuse is in-line with the input, so once blown nothing works.   

I am still looking at Gossen.  I have been trying to get some questions answered by them and downloaded their LabVIEW drivers.  The software looks fairly straight forward but I have been unable to locate any sort of programmers manual.  Maybe Dave will make the 121GW available soon.   
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on May 04, 2017, 06:39:20 pm
So I will give you that putting on of these counterfeits in say the UT61E's 500mA it would further improve the burden and I believe the diodes would handle the added current in that one case.  However they are not using 4000 series diodes and I have those large TVSs in there now.   I wouldn't attempt it on any meter I cared about without looking at the circuit to make sure it could handle it. 

Agreed!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 05, 2017, 10:53:16 pm
So I will give you that putting on of these counterfeits in say the UT61E's 500mA it would further improve the burden and I believe the diodes would handle the added current in that one case.  However they are not using 4000 series diodes and I have those large TVSs in there now.   I wouldn't attempt it on any meter I cared about without looking at the circuit to make sure it could handle it. 

Agreed!

The data I took at 504mA, the SIBA dropped 705mV and the UXCELL, 367mV.   So, 1.399 ohms for the SIBA and 0.728 ohms on the UXCELL.  At 220mA (upper end of 61E) the drop would be 308mV for the SIBA and 146mV for the UXCELL assuming it was linear.  If it were linear, that's a gain of 162mV.  It seems like a lot and indeed may be worth it but... again it's not linear.    So just for you let's look at the real world with another UXCELL fuse.


UT181A is in series with the UT61E and the BM869s is looking at the voltage across the 61E.  SIBA_drop showing 836.8mV of burden at 220.7mA.  Pretty much what I showed in the last video for the 61E.  Now look at the UXCELL_drop at the same current.  764.9mV of drop.   So in the real world, we gained 72mV is all.   Not much when you figure we are still over a half volt drop anyway.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 06, 2017, 02:00:09 am
Call me Brandy Loyale, but I just ticked on " I think the Fluke 87V is really a good meter and want to see if a third one would be better"

TBH I don't think a 3rd or 30th would make a lot of difference, but would like to ask if Mr. Smith can recommend some simple improvements to the 87V so it can survive more of his advanced Lab testing   >:D 

and still work after a shuffling casual walk on carpet touch n zap test   :horse:

An external protection box would be nice, so as not mess with the meter's insides and void warranties   :-+

No problem.  Many people are brand loyal. 

I have been researching Gossen a fair amount the last few months.  They used to offer a product that would increase the robustness of their meters.  I have been unable to find any further information about it and when I asked Gossen, they stated it was discontinued.   It would have been interesting to know more about it. 

You are correct that I never tested the 87V with my little grill starter or run the basic AC line test on it.  Now days, the ESD would be much closer to the standard as that little piezo was a pretty do nothing test.  It sure took out a lot of UNI-Ts though.   :-DD    If I ever do get another 87V, it won't get any special treatment next time.     

In all these cases, I am afraid there would be little I could recommend someone do to their meter.  For ESD, it's easy enough to control it in the home lab.  In the case of the 87V, I understand the one I looked last was one revision older than the current one being sold.  It is possible they made improvements to harden it.     

I keep holding out for Dave's new meter.  I am expecting that thing to be rock solid.   If it holds up as well as his rebranded 235, maybe we can do a run off between the Fluke 101, 115, the BM235 and the 121GW.   
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 06, 2017, 02:41:24 am
isn't that 121GW a rebranded Finest Instruments meter? if so, I wouldn't hold my breath...
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 06, 2017, 03:35:37 am
interesting... it looks like a finest aka klein...
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on May 06, 2017, 03:37:59 am
The 121GW is a Finest built meter, designed and constructed in cooperation with Dave Jones. It is also going to be fully certified to IEC CAT rating standards as far as Dave has said.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 06, 2017, 03:45:32 am
thanks
hopefully it won't be as slow in autoranging  and capacitor measurement as the 397, which is a painfully slow meter...
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on May 06, 2017, 04:18:26 am
SIBA_drop showing 836.8mV of burden at 220.7mA.  Pretty much what I showed in the last video for the 61E.  Now look at the UXCELL_drop at the same current.  764.9mV of drop.   So in the real world, we gained 72mV is all.   Not much when you figure we are still over a half volt drop anyway.

As with many things, real-world and/or typical usage may not be as significant as theoretical calculations. In this case, saving 10% likely wouldn't matter for most circumstances. The risk of poor protection, inconsistent production quality and performance, etc. would be significantly more compelling reasons not to use them.

Good stuff, Joe. Thanks for the additional test cases.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 08, 2017, 04:50:10 am
Joe:

Have you considered any of the Chauvin Arnoux/Metrix products for examination? For example the MTX 3293 is interestingly different from many meters. It's in a similar price range to the high end Gossens, but since Gossen are not doing so well in their customer support it might be time to abandon that idea and look elsewhere?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 09, 2017, 02:35:12 am
With Dave always talking about how great the Gossen is, it reminded me of another highly regarded meter that I tested that did not fair so well. 

A few friends of mine had watched Dave's video as well and asked me about running one.  When one of my friends sent me a Gossen ad last Winter (I'll hunt around for it) and the wording made it sound like it was indestructible, it just seemed fair to give them an opportunity to prove they are every bit as good as some of the other meters I have looked at.   

A quick search on their site and I found the link below along with some other info.

https://www.gossenmetrawatt.com/english/seiten/cautiondangerousmultimeters.htm (https://www.gossenmetrawatt.com/english/seiten/cautiondangerousmultimeters.htm)

Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 09, 2017, 04:29:44 am
What happens if you like a meter so much that you don't want to destroy it?  ;D

For example, the MTX 3293 has built-in data recording and graphing. along with IR and Bluetooth comms. Maybe Metrix are more forthcoming with their protocol information than Gossen?

I have no use for that meter, so for me it would only be a toy. But you have to admit it breaks the mold of standard meter designs...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 09, 2017, 11:43:05 am
Most line powered bench meters are not designed to be used with high energy circuits like the handhelds.  Imagine the poor electrician taking their 3458 to the job site?    :-DD   Handhelds are sometimes designed to be very robust and safe.  Personally, for my electronics hobby, I would have little use for a handheld meter.  The Brymen 869s has been an exception.

Normally I have no need for graphing or data logging.  That's what the PC and LabVIEW are for (which Metrix supports). I like the wireless RF link on the CEM meters.  It's been handy.   

Someone else had asked about running the Metrix brand in a YT comment.  Maybe it was you.  I looked around for pictures showing the internals.  There was not a lot of info.  Dave's channel is large enough, maybe one day they will send him one to do a quick show and tell.   If I get one, it will see the same basic tests that all the handhelds I get go through so they would have to be pretty sure of their product to ever send me one.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 13, 2017, 12:32:42 am
I have posted Part 1 of my review of the Gossen Metrawatt.  If you're looking for me to drool over it and put it on a pedestal to worship, don't watch. 

https://www.youtube.com/watch?v=9LjWtdgJhkg (https://www.youtube.com/watch?v=9LjWtdgJhkg)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on May 13, 2017, 01:21:46 am
On the contrary. Sounds like I must watch it to see what happened. :-/O
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on May 13, 2017, 01:33:28 am
On the contrary. Sounds like I must watch it to see what happened. :-/O

But it's only Part 1, which means he didn't destroy it yet.   



Er, well, either that or he DID destroy it and part 2 is about the resurrection effort.   :-DD



Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 13, 2017, 01:43:02 am
Sure looks pretty, swear I didn't DROOL!
Left us with CLIFFHANGER though, like a network series TV show.
I'm staying "tuned", to find out if the butler bugged the new meter!
Nice work Joe.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 13, 2017, 01:51:44 am
Someone on this site recently posted about knuckle draggers who blow stuff up on Youtube.

If only PhotonicInduction lived in Australia, then you two could take the piss out of some crap.

PhotonInduction is lame, any moron can break stuff, it's the lowest form of matter. The thing I like about Dave's videos is that for the most part they're informative and productive. There are already too many videos of knuckle draggers just breaking and blowing stuff up on youtube.

You are right, I stress them to the point of being damaged, attempt to repair them to better understand why they failed and on a few RARE occasions, have attempted to go Steve Austin on them making them stronger than they were before.  Then I repeat the cycle and attempt to stress them to the point of failure all over again.   And while I am waiting for the iron to heat up, I am watching PhotonicInduction!   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on May 13, 2017, 01:52:39 am
If you're looking for me to drool over it and put it on a pedestal to worship, don't watch. 

But I like watching people drool over DMMs while putting them on pedestals to worship!  :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on May 13, 2017, 03:45:39 am
I would like to know how often in the real world a surge or some other anomaly comes along and puts a technician at risk while in the process of troubleshooting a fault in a piece of (let's just say consumer) equipment.

My guess - not very damned often. Techs love the Fluke 87 and it's variants for a good reason. It's reliable and consistent, and safe. Period.

It is not necessary that it survive a gazillion volts at 1/2 height or whatever. In the EXTREMELY UNLIKELY event that it's ratings are exceeded in a given situation, the Fluke will "fail safe" and further - Fluke will fix it for FREE.

Meanwhile - you can rely on it's readings, accurate to a level exceeding spec by an order of magnitude even if the meter is over thirty years old.

What more can you ask from a multimeter for it's intended function?

I'm a Fluke fan-boy?

You bet - and for good reason.
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on May 13, 2017, 04:30:05 am
I would like to know how often in the real world a surge or some other anomaly comes along and puts a technician at risk while in the process of troubleshooting a fault in a piece of (let's just say consumer) equipment.

My guess - not very damned often. Techs love the Fluke 87 and it's variants for a good reason. It's reliable and consistent, and safe. Period.

It is not necessary that it survive a gazillion volts at 1/2 height or whatever. In the EXTREMELY UNLIKELY event that it's ratings are exceeded in a given situation, the Fluke will "fail safe" and further - Fluke will fix it for FREE.

Meanwhile - you can rely on it's readings, accurate to a level exceeding spec by an order of magnitude even if the meter is over thirty years old.

What more can you ask from a multimeter for it's intended function?

I'm a Fluke fan-boy?

You bet - and for good reason.

That might have been true in the past, but the market has evolved a lot since then. The competition are just as safe and accurate, while being cheaper and richer in functionality. The only thing Fluke seems to offer these days is the brand itself.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 13, 2017, 06:29:47 am
...
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 13, 2017, 01:54:47 pm
While I'm not sure about the frequency of the surges, without a doubt they do happen. A local employer, a mining operation, had a electrician injured when he was measuring receptacle voltage (995V Phase to Phase), apparently the PT's onboard the equipment were acting up and they were unsure as to why. When the electrician measured phase to phase the meter had an internal arc and pulled a arc on the terminals of the receptacle when he attempted to pull away. The meter was a Southwire meter, they eventually had to pull it due to a failed IP67 rating, you could try googling MSHA (Mine Safety and Health Administration and Southwire) and you might find something I'm not sure. I believe the IP67 failure was not a factor in the accident but it came up during the investigation.

Edit: Found it https://arlweb.msha.gov/Alerts/Equipment/2014-11-21-southwire%20alert.pdf (https://arlweb.msha.gov/Alerts/Equipment/2014-11-21-southwire%20alert.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on May 13, 2017, 02:06:27 pm
While I'm not sure about the frequency of the surges, without a doubt they do happen. A local employer, a mining operation, had a electrician injured when he was measuring receptacle voltage (995V Phase to Phase), apparently the PT's onboard the equipment were acting up and they were unsure as to why. When the electrician measured phase to ground (~575V), the meter had an internal arc and pulled a arc on the terminals of the receptacle when he attempted to pull away. The meter was a Southwire meter, they eventually had to pull it due to a failed IP67 rating, you could try googling MSHA (Mine Safety and Health Administration and Southwire) and you might find something I'm not sure. I believe the IP67 failure was not a factor in the accident but it came up during the investigation.

I was actually referring to consumer level equipment repair. The mere thought of high energy stuff scares the crap out of me.

My training pretty much ends where the plug goes into the wall.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 13, 2017, 02:08:54 pm
I would like to know how often in the real world a surge or some other anomaly comes along and puts a technician at risk while in the process of troubleshooting a fault in a piece of (let's just say consumer) equipment.

My guess - not very damned often. Techs love the Fluke 87 and it's variants for a good reason. It's reliable and consistent, and safe. Period.

It is not necessary that it survive a gazillion volts at 1/2 height or whatever. In the EXTREMELY UNLIKELY event that it's ratings are exceeded in a given situation, the Fluke will "fail safe" and further - Fluke will fix it for FREE.

Meanwhile - you can rely on it's readings, accurate to a level exceeding spec by an order of magnitude even if the meter is over thirty years old.

What more can you ask from a multimeter for it's intended function?

I'm a Fluke fan-boy?

You bet - and for good reason.

If I repaired consumer products or just considered how often my own AC line powered equipment has been damaged in my house over my lifetime, would I somehow feel it relates to what can happen through out the world under all conditions?   Would I ever suggest that any of the testing I show has anything to do with how safe a meter would be if exposed to a real surge condition?  Of course not.   

I would imagine there are people who believe jumping a fuse with wire is an acceptable practice for all environments. It may very well be a person could be fine in their little bubble.     

My interest has always been in low energy robustness.  That's why I make a bigger deal about the EMC than the safety standards.  It's not that I don't care about safety as much as it is rare I am at risk in the home hobby lab.

I can understand owning an expensive meter like the 87V, having total confidence in it and then with all your love for the meter, someone comes along and shows that it can be damaged at levels that many low cost meters also fail at.  Rather then simply acknowledge it, you choose to defend it and claim the tests have nothing to do with what you do in real life.  That's all fine.  I see the same response from many of the meters I run.  I would expect that if I ran Dave's 121GW and it failed the puny grill starter test, Dave would defend that the test was pointless and not how it is conducted in the real world. 

But again, that's not why I run the tests.  I have no love for any meter. I would toss the Brymen aside if I found something I liked better.  I run them against a standard to see how electrically robust they are with one another.  I can't help it if you feel Fluke got a bad shake in the testing. I run the test and present the findings. If you have no interest in watching the videos and feel there is nothing you can learn from them, to be honest I don't understand why you are wasting your time with them.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 13, 2017, 02:24:43 pm
While I'm not sure about the frequency of the surges, without a doubt they do happen. A local employer, a mining operation, had a electrician injured when he was measuring receptacle voltage (995V Phase to Phase), apparently the PT's onboard the equipment were acting up and they were unsure as to why. When the electrician measured phase to ground (~575V), the meter had an internal arc and pulled a arc on the terminals of the receptacle when he attempted to pull away. The meter was a Southwire meter, they eventually had to pull it due to a failed IP67 rating, you could try googling MSHA (Mine Safety and Health Administration and Southwire) and you might find something I'm not sure. I believe the IP67 failure was not a factor in the accident but it came up during the investigation.

I was actually referring to consumer level equipment repair. The mere thought of high energy stuff scares the crap out of me.

My training pretty much ends where the plug goes into the wall.

Oops, I may have misread your post all together!   If so sorry about that.

I think it would be difficult to say.  I had a radio given to me that had been connected to a tower outside of the home.  Lightning hit the tower and the radio died.  Insurance covered it.  When I removed the cover, there was a fairly large hole in the metal chassis.  It was impressive to see. 

I have had friends tell me other stories over the years of their own experience with lightning hits in their homes. Funniest one was a toaster that caught fire.  Lucky they were home at the time.  Worst was a neighbors house that caught fire.  We have a tree that was hit and it took out about an inch of bark down the length of the tree. 

They do sell the crap out of line cord surge protectors for a reason. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 13, 2017, 02:56:03 pm
I would like to know how often in the real world a surge or some other anomaly comes along

It definitely happens.

If you're the sort of person who pokes bits of metal into mains sockets then why skimp?

It's not even a case of skimping: The safest meter in joe's testing is the Fluke 101 which costs $42, shipping included. If socket-poking or power supply repair is a daily thing then you'd have to be an idiot to use anything else.

For working with low voltage DC though isolated power supplies then it's not so critical. Anything that passes the static electricity test will be probably be good enough.

(just don't lend it to anybody or leave it where children might find it and poke it into a mains socket on a random setting...)
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on May 13, 2017, 05:10:10 pm
I would like to know how often in the real world a surge or some other anomaly comes along

It definitely happens.

Please forgive my ignorance, could you please describe under what conditions this happens? And what happens?

I see a lot of discussion here that these cheap-ass multimeters are "low voltage only". Yet *none* of them failed to measure voltage in mains. I also didn't see meters failing below 1kV. So, where the danger comes from? (assuming probes are of any decent quality).

My next question would be how failing to survive a "high-energy test" compromises safety (if the meter does not completely explode, of course).
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on May 13, 2017, 05:56:46 pm
Think of you having them in a power outlet, with an airconditioner plugged into the power strip. You are measuring the drop in mains voltage when the unit power on the compressor. While doing that, with the compressor running, your breaker trips, disconnecting the compressor. However, there is a very large transient from the still running motor, and this generates a 2kV or more pulse on the mains wiring leading to the unit. Your meter gets this pulse, with more than enough energy to damage it, and a non protected meter will have the input side blown. Then somebody turns the mains back on, and you, believing that the meter reading of zero volts, then goes to disconnect the mains wiring from the compressor, and connect yourself across the mains. RIP
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 13, 2017, 06:09:53 pm
Please forgive my ignorance, could you please describe under what conditions this happens? And what happens?

I see a lot of discussion here that these cheap-ass multimeters are "low voltage only". Yet *none* of them failed to measure voltage in mains. I also didn't see meters failing below 1kV. So, where the danger comes from? (assuming probes are of any decent quality).

My next question would be how failing to survive a "high-energy test" compromises safety (if the meter does not completely explode, of course).

This has been discussed before, but no one can agree on how relevant the safety precautions are.

There can be dangerous power surges in the mains due to nearby lightning strikes or faults in the distribution system that allow high voltages to jump over onto the low voltage side. The usual impact of this is to damage equipment in your house like televisions or computers, or in the worst case to set your house on fire.

Now you have to ask what is the probability that such an event will occur while you are probing the mains with your meter? In my case since I measure the mains for maybe a few seconds in any given year (about 0.00005% of the time) I would say the probability is essentially zero that I will ever encounter a dangerous surge while using a multimeter. Especially since I am not likely to probe the mains during a lightning storm.

If someone is an electrician who uses the meter every day as part of their job, then the probability is different. If I were using a meter at work I would want a safe meter.

A different question is static electricity. I can certainly build up a charge while walking across the carpet. Most things I touch are not damaged by this, but a meter is different. It has metal probes that are specifically designed to carry electricity inside the meter and apply it to the internal circuits. So in the unlikely case that I pick up a big charge and then touch the metal part of the meter probe, I could potentially fry the meter. Here I would agree that protection is warranted for a typical home user.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 13, 2017, 06:28:31 pm
My next question would be how failing to survive a "high-energy test" compromises safety (if the meter does not completely explode, of course).

That's the thing - they often do explode. Watch the videos in this thread, :popcorn: I wouldn't want to be holding one in my hand when they go off.

Even if they don't explode they might be damaged internally and give false readings or catch fire next time you connect them to mains voltage.

Or ... the cheapo cables could melt (never wrap cables around your hand, just in case).

Under what conditions? Lightning strikes aside; any large inductor can generate many thousands of volts if it's suddenly disconnected on one side. Do you know what your neighbor is doing in his garage right now?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 13, 2017, 06:36:51 pm
Not too long a member posted about doing some wiring in their RV and going across the lines with the meter in the current mode.    We have seen a few posts here about the MOTs.  There was the tractor magneto. Funny when you start to think about the ways people have damaged their meters. 

With some of the crap meters I have looked at where they share the current and voltage input then toss a glass fuse in there with it, that we don't here some better stories. 

Fluke has some good info on their website.   I've posted a few links in this thread.  You could Google "ABCs of multimeter safety - Fluke"

Maybe read the following:
https://www.lanl.gov/safety/electrical/docs/electrical_measurement.ppt#32 (https://www.lanl.gov/safety/electrical/docs/electrical_measurement.ppt#32)

The PDF linked here may be of interest as well
http://gps.sozialnetz.de/go/id/pn/ (http://gps.sozialnetz.de/go/id/pn/)

Title: Re: Handheld meter electrical robustness testing.
Post by: exe on May 13, 2017, 08:46:59 pm
Fluke has some good info on their website.

Thank you for the links. I read them, but I don't trust them. We too have a marketing department that weekly writes scary articles to pursue people to use our services. And, despite Fluke wildly insists, I don't care if my DMM to survives a 10kV transient. I want to survive it, but I don't really care about equipment. But two things I learned from that docs: 1) do not use crappy probes 2) be careful with inductive loads. Still not clear how I can get damaged in other cases. I can only think of a case that the arc gets through the DMM's body.

That's the thing - they often do explode. Watch the videos in this thread

No, that's the author makes them exploding. How many meters actually exploded just by connecting to mains? That's my question: how dangerous they are when you don't try to "measure" 3kV pulses on purpose and use proper probes. It doesn't mean I'm proposing to abandon you flukes, guys, and replace them with Mastech or Uni-T. I'm not saying this. Please keep burning multimeters. I just want to understand how real the threat is.

Some scientific date would be nice. Like,  10% of Mastech customers die annually because of electric shock. Or, Fluke users live 10 years longer and have less changes of divorce. Or at least some statistics how many transient a typical household has (I found no such date).


There can be dangerous power surges in the mains due to nearby lightning strikes or faults in the distribution system that allow high voltages to jump over onto the low voltage side. The usual impact of this is to damage equipment in your house like televisions or computers, or in the worst case to set your house on fire.

I was waiting for this comment :). To my mind, home equipment is much less protected from power surges than an "average" multimeter. So I think for an average hobbyist there is more danger to get killed/injured by a dishwashing machine, or a microwave, or a faulty phone charger. Or by my DIY power supply, which only has a conventional toroidal transformer to protect me from mains (and maximum isolation voltage not even specified).

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 13, 2017, 09:08:25 pm
I was waiting for this comment :)

Nobody's saying you're definitely going to die. The combination of events needed to blow up your multimeter when it's connected to the mains at home is very unlikely.

OTOH so are the chances of dying in a car crash. I bet your car has seatbelts and airbags though.  :popcorn:

How many meters actually exploded just by connecting to mains?

Enough that they eventually developed some standards and safety ratings.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 13, 2017, 09:25:35 pm
To exe and others, this entire thread and all Joe's vids need to be studied to fully comprehend the robustness and safety aspects Joe has enlightened us all about.
Early on Joe mentioned he had lost faith in Fluke meters after one he owned expired from static damage.....it was news to me that meters could be so easily damaged  :o and I've been a close watcher of Joe's work since.
His tests are now more advanced and refined from those days and now when he lines DMM's side by side we have a very good look at how they compare against one another.

Joe's work will live on for decades here and to be found by others and we all owe him a depth of gratitude for the issues he has raised and explored for the benefit of us all.

Edit
In the time that it takes write a reply to challenge findings or opinions one could have read a good # of posts in this thread and learnt something.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2017, 12:32:51 am
I have a ceiling fan and needed to replace its switch.  Drove to all the local stores and could not find one switch that was UL rated.  This switch has the potential to cause an electrical fire.  I would GLADLY pay for a good certified switch but there are none to be had.   We do not make them here anymore that I have found.   I doubt the average consumer will care unless something happens.  Even then my guess is the finger would be pointed at the installation and not the switch itself.  There used to be public service announcements to help educate the general population about things like UL.  Now we talk about quality rather than practice it.  Fan I would guess is I would imagine nearing 40 years old now.  The larger white switch is make by KTE and was the original The smaller switch is what I used to replace it.  Note the CSA and RL marks on it.  The pull mechanism in this switch failed in maybe 5 years or so.  That's how bad the quality is.   The new switch is even cheaper made with no cert.   

Keeping stats like this I'm sure is a mental illness of sorts, like stamp collecting.
 
About home appliances, they have their own safety ratings, for now.  Like the switch, I am not suggesting all the crap we import is certified for safety.  The outside metal cases are grounded.  Double insulation, single ground point.  Bond wire testing.  HI-POT testing.   Nothing like a hand held device you would hold in your hand while you are probing mains.  Not that someone could not rewire their microwave to short the two lines together while the covers are off with no fuse in place, but I have seen a few crap meters that had no fuse where someone could easily do just this, short the lines.   And even if you did own a meter that had HRC fuses to help protect you, nothing prevents you from being stupid and shorting out the fuse with a wire.   

Again, I have little to no interest in multimeter safety because I do not work in an industry where it concerns me and I know enough to limit my own risks at home.   

If I Google "electrical fatality statistics", there's all sorts of information that comes up.  I added the word "multimeter" to the search (this stuff is not rocket science).  Now here is an interesting article. Could be a fear based ad still.

http://iaeimagazine.org/magazine/2008/07/16/multimeter-accident-prevention-plan-an-electrical-inspectors-survival-guide/ (http://iaeimagazine.org/magazine/2008/07/16/multimeter-accident-prevention-plan-an-electrical-inspectors-survival-guide/)
Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on May 14, 2017, 12:37:22 am



If I repaired consumer products or just considered how often my own AC line powered equipment has been damaged in my house over my lifetime, would I somehow feel it relates to what can happen through out the world under all conditions?   Would I ever suggest that any of the testing I show has anything to do with how safe a meter would be if exposed to a real surge condition?  Of course not.   

I would imagine there are people who believe jumping a fuse with wire is an acceptable practice for all environments. It may very well be a person could be fine in their little bubble.     

My interest has always been in low energy robustness.  That's why I make a bigger deal about the EMC than the safety standards.  It's not that I don't care about safety as much as it is rare I am at risk in the home hobby lab.

I can understand owning an expensive meter like the 87V, having total confidence in it and then with all your love for the meter, someone comes along and shows that it can be damaged at levels that many low cost meters also fail at.  Rather then simply acknowledge it, you choose to defend it and claim the tests have nothing to do with what you do in real life.  That's all fine.  I see the same response from many of the meters I run.  I would expect that if I ran Dave's 121GW and it failed the puny grill starter test, Dave would defend that the test was pointless and not how it is conducted in the real world. 

But again, that's not why I run the tests.  I have no love for any meter. I would toss the Brymen aside if I found something I liked better.  I run them against a standard to see how electrically robust they are with one another.  I can't help it if you feel Fluke got a bad shake in the testing. I run the test and present the findings. If you have no interest in watching the videos and feel there is nothing you can learn from them, to be honest I don't understand why you are wasting your time with them.

My intention was not to diminish your tests or your results, but I do think my question was valid on it's own. Possibly it might have been better posted in another context. By all means do keep it up and I don't feel I'm wasting any time watching your videos.

And as for learning - there's no doubt in my mind your training and experience is an order of magnitude better than mine, if not more.

I do cringe a little at some of your tests...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2017, 12:48:12 am
...

I bet your car has seatbelts and airbags though.  :popcorn:
...

Enough that they eventually developed some standards and safety ratings.
And don't forget HRC fuses that I recently was schooled on how they can easily be replaced with wire.   I do like the slot cut into the case to allow for maybe an external power supply.  Good stuff. 
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 14, 2017, 12:52:37 am
I have no problem with appropriate levels of safety and robustness, but requirements should be measured against the actual levels of danger in the environment.

For instance, I measure things related to electronics on the workbench, either battery powered or isolated from the mains. If protection devices made a meter less suitable for those measurements, I would rather my instrument didn't have such protection devices. A fuse, for example, increases the burden voltage on current measurements. I have never blown a meter fuse, and I never intend to. Why do I need one? Let me choose a meter with a fuse for electrical work, and a meter without a fuse for electronic measurements.

The mains. Why do I care? I measured it once and it was 120 V AC at 60 Hz. What a surprise! Do I never need to measure it again? If I am doing electrical work around the house, I care if the power is disconnected or not. For that I should use a voltage test device. A multimeter is not the right tool for that job. Very occasionally I might care about continuity. So yes, a continuity meter is good, after I have verified the power is off.

Sadly, all the safety codes and regulations are designed to guard against the ignorant, the people who don't know what they are doing. This is called "the nanny state". It's a shame, but I guess we have to live with it.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 14, 2017, 01:13:43 am
Yes Ian, we need protecting from ourselves when we know no better.

There are very common use cases where a DMM might also be exposed to unexpected transients, the first to mind would be the collapsing field (back EMF) from a relay coil or similar.
It might only have a low voltage applied to it but interrupt the supply and you could be in for a shock and a buggered DMM.
How high could the back EMF event be.....as high as it needs to be to find a discharge path.  :scared:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2017, 01:54:39 am
My intention was not to diminish your tests or your results, but I do think my question was valid on it's own. Possibly it might have been better posted in another context. By all means do keep it up and I don't feel I'm wasting any time watching your videos.

And as for learning - there's no doubt in my mind your training and experience is an order of magnitude better than mine, if not more.

I do cringe a little at some of your tests...

I am not a repair tech nor am I an electrician.  I am open to discussing your thoughts about the testing I have done.  It's not like there is a pool of information where there are industry standards on how to benchmark meters for their electrical robustness.  This is what happens when you take a simple idea like "I wonder if a cheap $50 meter is more robust than a $400+ meter" and act on it.  Because it's not something that is commonly done (maybe never) it leads to confusion.  Then we have the internet with it's vast pools of experts on the mater.  After a couple of years, it seems we have heard it all. 

There is little you or anyone could post that would diminish the testing I have done to date.  It's just data to me that I collect it and present.  Everything is open as far as what I have done.  If you feel your 87V is "reliable and consistent, and safe. Period"  that's all fine.  Your personal feelings do not go against anything in the data I have shown for the 87V.  I have never collected data for safety or reliability.  Nor have I studied what I would consider makes a meter consistent.  So I won't disagree with you as I have no data that says otherwise.   

I am only looking electrical robustness and the 87V is just not very robust when compared with some of the other meters I have looked at.  I will give you that the 87V is way more robust than the UNI-T's that failed the puny grill starter test.  That has become a standing joke around here.  Even my wife will ask, "did it fail the grill starter" :-DD 

What's to cringe at?   :-DD  The energy levels are fairly low, I have a fair amount of safety checks built into the generator and if I play with something that may pose a high risk it's behind a half inch thick plate of Plexiglas (more to protect the camera).   Any time I play with the half cycle generator, I am a fair way away and out of the direction of the blast.  The risk is low for me but it's not something I would suggest the fuse jumping crowd get involved with.   

https://www.copeplastics.com/plexiglas-impact-resistance.html (https://www.copeplastics.com/plexiglas-impact-resistance.html)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2017, 02:08:35 am
Sadly, all the safety codes and regulations are designed to guard against the ignorant, the people who don't know what they are doing. This is called "the nanny state". It's a shame, but I guess we have to live with it.

IMO, it has a lot to do with trade as well.   
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 14, 2017, 03:31:10 am
I have a ceiling fan and needed to replace its switch.  Drove to all the local stores and could not find one switch that was UL rated.  This switch has the potential to cause an electrical fire.  I would GLADLY pay for a good certified switch but there are none to be had.   We do not make them here anymore that I have found.   I doubt the average consumer will care unless something happens.  Even then my guess is the finger would be pointed at the installation and not the switch itself.  There used to be public service announcements to help educate the general population about things like UL.  Now we talk about quality rather than practice it.  Fan I would guess is I would imagine nearing 40 years old now.  The larger white switch is make by KTE and was the original The smaller switch is what I used to replace it.  Note the CSA and RL marks on it.  The pull mechanism in this switch failed in maybe 5 years or so.  That's how bad the quality is.   The new switch is even cheaper made with no cert.   

Keeping stats like this I'm sure is a mental illness of sorts, like stamp collecting.
 
About home appliances, they have their own safety ratings, for now.  Like the switch, I am not suggesting all the crap we import is certified for safety.  The outside metal cases are grounded.  Double insulation, single ground point.  Bond wire testing.  HI-POT testing.   Nothing like a hand held device you would hold in your hand while you are probing mains.  Not that someone could not rewire their microwave to short the two lines together while the covers are off with no fuse in place, but I have seen a few crap meters that had no fuse where someone could easily do just this, short the lines.   And even if you did own a meter that had HRC fuses to help protect you, nothing prevents you from being stupid and shorting out the fuse with a wire.   

Again, I have little to no interest in multimeter safety because I do not work in an industry where it concerns me and I know enough to limit my own risks at home.   

If I Google "electrical fatality statistics", there's all sorts of information that comes up.  I added the word "multimeter" to the search (this stuff is not rocket science).  Now here is an interesting article. Could be a fear based ad still.

http://iaeimagazine.org/magazine/2008/07/16/multimeter-accident-prevention-plan-an-electrical-inspectors-survival-guide/ (http://iaeimagazine.org/magazine/2008/07/16/multimeter-accident-prevention-plan-an-electrical-inspectors-survival-guide/)

The article you linked to, was worth reading. I was unaware of "fused" test leads. While probably not desirable in electronics work, certainly worth considering for high voltage electrical jobs.

http://www.epanorama.net/newepa/2011/12/29/fused-multimeter-probes/ (http://www.epanorama.net/newepa/2011/12/29/fused-multimeter-probes/)

https://www.amazon.com/Fluke-SureGrip-Degree-Operating-Temperature/dp/B005GFLCGK?th=1 (https://www.amazon.com/Fluke-SureGrip-Degree-Operating-Temperature/dp/B005GFLCGK?th=1)

Unfortunately, the last statement in the article (1st link):

"People buying cheap meters typically wouldn’t be interested in spending more than the cost of the meter on leads. Sadly, safety is often overlooked."
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 14, 2017, 03:49:41 am
...

I can always count on you adding to the technical discussion.  :-DD   Did you need to add or remove a period?  :-DD

I posted a link to a picture of a nasty exploded glass fuse inside a meter... then I thought it might not be such a good idea, and I couldn't delete the post...

Title: Re: Handheld meter electrical robustness testing.
Post by: exe on May 14, 2017, 08:04:31 am
Thank you very much, guys, for comprehensive answers. Now got my own opinion on the subject.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 14, 2017, 08:16:33 am
They had to remove the carpets on the ISS:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 14, 2017, 09:12:09 am
They had to remove the carpets on the ISS:

It's all extra weight, and accidentally dropping one isn't much of an issue up there.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 14, 2017, 09:14:06 am
Magnetic hangers, too. They're actually a safety feature, to free up a hand and get the meter a bit further away.

And of course you're supposed to wear gloves and safety glasses, too.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 14, 2017, 04:24:20 pm
They had to remove the carpets on the ISS:

It's all extra weight, and accidentally dropping one isn't much of an issue up there.

I think Wytnucls meant to reduce the danger of static electricity blowing up the meters...
Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on May 14, 2017, 04:58:43 pm
My intention was not to diminish your tests or your results, but I do think my question was valid on it's own. Possibly it might have been better posted in another context. By all means do keep it up and I don't feel I'm wasting any time watching your videos.

And as for learning - there's no doubt in my mind your training and experience is an order of magnitude better than mine, if not more.

I do cringe a little at some of your tests...

I am not a repair tech nor am I an electrician.  I am open to discussing your thoughts about the testing I have done.  It's not like there is a pool of information where there are industry standards on how to benchmark meters for their electrical robustness.  This is what happens when you take a simple idea like "I wonder if a cheap $50 meter is more robust than a $400+ meter" and act on it.  Because it's not something that is commonly done (maybe never) it leads to confusion.  Then we have the internet with it's vast pools of experts on the mater.  After a couple of years, it seems we have heard it all. 

There is little you or anyone could post that would diminish the testing I have done to date.  It's just data to me that I collect it and present.  Everything is open as far as what I have done.  If you feel your 87V is "reliable and consistent, and safe. Period"  that's all fine.  Your personal feelings do not go against anything in the data I have shown for the 87V.  I have never collected data for safety or reliability.  Nor have I studied what I would consider makes a meter consistent.  So I won't disagree with you as I have no data that says otherwise.   

I am only looking electrical robustness and the 87V is just not very robust when compared with some of the other meters I have looked at.  I will give you that the 87V is way more robust than the UNI-T's that failed the puny grill starter test.  That has become a standing joke around here.  Even my wife will ask, "did it fail the grill starter" :-DD 

What's to cringe at?   :-DD  The energy levels are fairly low, I have a fair amount of safety checks built into the generator and if I play with something that may pose a high risk it's behind a half inch thick plate of Plexiglas (more to protect the camera).   Any time I play with the half cycle generator, I am a fair way away and out of the direction of the blast.  The risk is low for me but it's not something I would suggest the fuse jumping crowd get involved with.   

https://www.copeplastics.com/plexiglas-impact-resistance.html (https://www.copeplastics.com/plexiglas-impact-resistance.html)

I just cringe at the impending destruction of a perfectly decent (for most of us anyway) meter. It's cool you're able to fix most of them however.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2017, 06:36:58 pm
I just cringe at the impending destruction of a perfectly decent (for most of us anyway) meter. It's cool you're able to fix most of them however.

If you would have taken the time to look at the on-line spreadsheet, in the first set of tests I ran 13 meters.  Of these, 3 were repaired and 1 survived without damage.  When I changed to the new generator, I have ran 40 meters.  Some of these were damaged during the first tests and had been repaired.  Of these, 13 where undamaged or repairable. 

The few that have had no detectable damage to date are the Fluke 101, 115 and the Brymen BM235.  The HIOKI DT4252 was right there.  Also, no other meter has withstood the levels that 5KY's Fluke 107 was exposed to.  The 107, even though its damaged, has proven to be the most robust of the meters I have looked at.  Of course all that data is on-line.

So roughly 30% recovery is all.  Certainly not what I would consider most.  Normally the lower end meters just don't have enough protection to save the custom IC.  Of the meters I keep, I have no use for the vast majority of them beyond using them as a visual comparison against other meters.  Once they have been stressed, they really have no value.  I would not give them away because of the risk.  A member did ask for a few parts off one once which I took the time to strip and send to them.  Not even a simple thank you. 

I have a job, pay taxes and buy these meters out of pocket.  There's no handouts and I am certainly not asking for any.  No one pays me to do these reviews.  I don't work for a company that produces, distributes or sells handheld meters of any kind.  My interest is in seeing how the meters compare with one another and that means running them to failure.

I understand there being people who can't afford a meter.  Although I have no idea why they would be wasting time on their cell phones watching my videos. I certainly understand wanting to feel good about the items you buy, especially when you feel you are buying high quality products and paying a premium.  If you don't want to know how the meters compare, the best thing is just not watch.  There are reviews where people just talk about the input circuitry and then give you their opinions.  I doubt you would find a bad review of the 87V if this is all you are after.
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on May 14, 2017, 06:47:55 pm
Yeah, kids in Africa could have eaten those meters!  :palm:

When will we see part 2 on the Gossen? The suspense is killing me!
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 14, 2017, 07:05:13 pm
I'm sure mzacharias is not the only one who cringes slightly at the destruction of perfectly functional items, even if it is in the name of science.

What a meter may lack in robustness it may make up for in other qualities. For example, the Radio Shack 22-812 meter that doesn't have very good input protection. It is a meter that I rather like for it's PC communication and data logging capabilities. I wrote software that allows me to plug two, three or any number of them into a computer and log measurements from them all simultaneously, something that the data logging programs from meter vendors do not typically allow you to do. Add to that that the meter is (was) inexpensive enough that it was actually practical to own two, three or more of them.

I would like to add the BM869s to my logging system, but the vendor's cable requires me to figure out how to program against the USB interface, and I cannot find a simple serial interface for it unless I make one. And even if I did, the 869 costs way more than the 22-812, so owning lots of them is not so easy to consider.
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 14, 2017, 08:33:51 pm
Yeah, kids in Africa could have eaten those meters!  :palm:

When will we see part 2 on the Gossen? The suspense is killing me!

Gonna need to stock up on more POPCORN!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 14, 2017, 11:57:20 pm
Would the Fluke 114, 115, 116, 117 series survive carpet surfing reasonably well such as the 101 or 107?

I need the TrueRMS, min max and Low Z features which 101 and 107 lack

My 114 has held up well so far, not that I have done any serious deliberate carpet surfing with it.. yet 

That said, if I have to spend $100 (on yet another meter  :-\ ) that will survive carpet trekking in an office to office client troubleshoot scenario,
what choice is there ?  :-//

BTW:  what's the continuity buzzer like on the 101 and 107?  If it's not typical  'Fluke Speed' the meter is a no go for me.

Of course, after seeing that report I linked where the lab did not directly test the leads, it does tend to water down the consumers trust (or at least my trust) in independent  certifications.  Or maybe I am doing it all wrong and the UNI-T would have survived.  :-//  IMO, the leads would be tested but I have seen reports like this before.   The Gossen and the 121GW if/when it becomes available will also be tested this way.  Direct discharges to the inputs.   

Anyway, I have only tested the Fluke 101, 107 and 115.  All certified for the EMC standards.  All can survive the puny grill starter and the new gun.  The 115 does tend to hang but I have yet to kill it.  These are direct discharges to the ports.   My guess is you would be hard pressed to damage your 114 this way but I have never looked at one.  I wouldn't run out a but a new meter if the 114 does what you want.   

You could prove it to yourself and try to damage your 114 by petting your cat, sliding across the carpet, whatever you can come up with for ESD around the home or lab.  Then post about it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 15, 2017, 01:29:00 am
For continuity, I measure the open circuit voltage, short circuit current, 50% DC, max frequency before meter skips, lowest detectable pulse, short circuit resistance and resistance that it opens back up.  I do not measure the beepers sound pressure or the audio frequency.  I also don't record if they latch or not.   

I have data for both the 115 and 101 but I never measured the 107. 
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 15, 2017, 03:10:51 am
Thanks,  I will assume the 114 and 115 will have same performance being the same build style

and same deal with 101 and 107

perhaps, but never assume anything...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 15, 2017, 04:00:58 am
Would you know how well the continuity buzzer on the 101 and 107 compares to the 115?

If only there was a spreadsheet somewhere with actual data on this...  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on May 15, 2017, 04:11:37 am
...

I can always count on you adding to the technical discussion.  :-DD   Did you need to add or remove a period?  :-DD

I posted a link to a picture of a nasty exploded glass fuse inside a meter... then I thought it might not be such a good idea, and I couldn't delete the post...

Ah, mystery solved. In such cases perhaps it would be helpful to put something similar to "-- post deleted --" in the body to minimize confusion, speculation, and the like.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 15, 2017, 04:13:55 am
...

I can always count on you adding to the technical discussion.  :-DD   Did you need to add or remove a period?  :-DD

I posted a link to a picture of a nasty exploded glass fuse inside a meter... then I thought it might not be such a good idea, and I couldn't delete the post...

Ah, mystery solved. In such cases perhaps it would be helpful to put something similar to "-- post deleted --" in the body to minimize confusion, speculation, and the like.

Indeed, good point...
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on May 15, 2017, 12:09:51 pm
I have a ceiling fan and needed to replace its switch.  Drove to all the local stores and could not find one switch that was UL rated.  This switch has the potential to cause an electrical fire.  I would GLADLY pay for a good certified switch but there are none to be had.   We do not make them here anymore that I have found.   I doubt the average consumer will care unless something happens.  Even then my guess is the finger would be pointed at the installation and not the switch itself.  There used to be public service announcements to help educate the general population about things like UL.  Now we talk about quality rather than practice it.  Fan I would guess is I would imagine nearing 40 years old now.  The larger white switch is make by KTE and was the original The smaller switch is what I used to replace it.  Note the CSA and RL marks on it.  The pull mechanism in this switch failed in maybe 5 years or so.  That's how bad the quality is.   The new switch is even cheaper made with no cert.   


You can't always trust something that is stamped with a "UL" label, either because it may be faked.
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on May 15, 2017, 12:39:31 pm
While I'm not sure about the frequency of the surges, without a doubt they do happen. A local employer, a mining operation, had a electrician injured when he was measuring receptacle voltage (995V Phase to Phase), apparently the PT's onboard the equipment were acting up and they were unsure as to why. When the electrician measured phase to phase the meter had an internal arc and pulled a arc on the terminals of the receptacle when he attempted to pull away. The meter was a Southwire meter, they eventually had to pull it due to a failed IP67 rating, you could try googling MSHA (Mine Safety and Health Administration and Southwire) and you might find something I'm not sure. I believe the IP67 failure was not a factor in the accident but it came up during the investigation.

Edit: Found it https://arlweb.msha.gov/Alerts/Equipment/2014-11-21-southwire%20alert.pdf (https://arlweb.msha.gov/Alerts/Equipment/2014-11-21-southwire%20alert.pdf)

Jordan,

I am not an electrician, I am a Facilities Engineer (Mechanical) and my company offered a training course on NEC's Arc Flash standards, a few years ago, that I took and learned quite a bit.  In my job, I don't actually open up equipment and put a meter on them, I would have our in-house Electricians do that, however, I do need to sometimes look on as an Electrician or Controls Mechanic troubleshoot a piece of equipment, so I do need to be aware of arc flash dangers and what to look for.  However, while I am not an Electrician, I know enough to get into trouble and to avoid trouble  ;D and I am inclined to say that a multimeter is wrong device to measure voltage when you are that close to most multimeter's design limits (i.e. 995V circuit is too close to a typical industrial multimeter's 1KV limit, which is what most multimeters state are their limits, and those that aren't typically have a much lower rating).  One of the ex. in that class was an HVAC technician trying to troubleshoot a 4160V, chiller.  There was the HV side and a LV side (not sure what the voltage on the LV side was, but it was used for the chiller controls), the tech found that the LV side appeared to be OK, so without thinking he hooked his multimeter to the HV side and the next thing he knew there was a flash of light (the meter "blowing up") and he was on fire and running through the building.  He lived long enough to tell his coworkers that he realized he used the wrong tool for the job. Like I said, I am not an Electrician, therefore I don't know what's available to use to measure voltage drop for high voltage circuits, but it seems to me that a multimeter is the wrong device, or at the very least marginal, even at the lower end of NEC's definition of High Voltage circuits (600V and above).
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on May 15, 2017, 01:03:14 pm
I would like to know how often in the real world a surge or some other anomaly comes along and puts a technician at risk while in the process of troubleshooting a fault in a piece of (let's just say consumer) equipment.

Since I discovered this site which has always stressed getting meters that meet their CAT ratings, I have wondered the same thing myself, only from a slightly different perspective, I always felt that if these surges were so common place, then there'd be be tons of folks crying about their busted electronics, like their 'spensive, flat screen, UHTV's, computers, smart phones (while charging), etc. I am sure they are not "hardened" for what would be considered CAT 2 transients, like a Fluke or other reputable multimeter, so there should be many failures of these kinds of equipment.  And, if it were really a problem, there'd be an outcry to harden electronics to survive these transients.  At least in the US, you don't really see that, which leads me to believe overall the US has fairly clean electric supply (as opposed to generation, but that would be a different discussion ::)), but as others have said, that may not be the case in other parts of the world, so a meter that meets its CAT rating may be more of a necessity in those areas.  I have not known anyone who has lost a piece of electronic equipment due to a transient unless lightning was involved.     

But, that said, I do understand the position of this site, its hard to argue being less safe and recommending meters that will obviously not meet their CAT ratings and could potentially put someone's life in danger if, for example, an Electrician is lead to believe that an UT-66E is just as good as a Fluke IV for much less, and the Electrician proceeds to buy and use his UT-66E on industrial equipment.  I think that is why people stress that the UT-66E (and other inexpensive multimeters) is perfectly fine if your plan is to use it on what most folks refer to as "LV" circuits (i.e. <120V) and don't recommend using it to measure inside your electrical panel. 
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on May 15, 2017, 01:55:38 pm
DMM in particular, are expected to be used in fault conditions to its appropriate CAT rating, not clean line power used by consumers.  Most PSU are made with surge in mind the ITIC curve is the common standard:

https://www.eevblog.com/forum/chat/understanding-%27itic(cbema)-curve%27/ (https://www.eevblog.com/forum/chat/understanding-%27itic(cbema)-curve%27/)

In real world use surge exposure depends on what you do.  If you are an electrician working any source of inductive loads or outdoors during bad weather, even far away from your location, CAT III and IV conditions occur fairly daily.  The only times I've been hit was working outdoors on land or ship board electronics. 5x in 30+ years but I'm not a service engineer or tech, and was doing field testing of electronic devices and normally not exposed to such spikes.  Its not life threatening in my application, but being without a DMM miles from civilization and no way to do measurements, pretty much ends the installation.  But if we use a true Fluke DMM, we never have problems no matter where we go.

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 15, 2017, 07:45:49 pm
I would like to know how often in the real world a surge or some other anomaly comes along and puts a technician at risk while in the process of troubleshooting a fault in a piece of (let's just say consumer) equipment.

Since I discovered this site which has always stressed getting meters that meet their CAT ratings, I have wondered the same thing myself, only from a slightly different perspective, I always felt that if these surges were so common place, then there'd be be tons of folks crying about their busted electronics, like their 'spensive, flat screen, UHTV's, computers, smart phones (while charging), etc. I am sure they are not "hardened" for what would be considered CAT 2 transients, like a Fluke or other reputable multimeter, so there should be many failures of these kinds of equipment.  And, if it were really a problem, there'd be an outcry to harden electronics to survive these transients.  At least in the US, you don't really see that, which leads me to believe overall the US has fairly clean electric supply (as opposed to generation, but that would be a different discussion ::)), but as others have said, that may not be the case in other parts of the world, so a meter that meets its CAT rating may be more of a necessity in those areas.   
I am not an expert in this area, but I think that outcry may have happened and thus HiPot testing is used to address this concern for consumer electronics and appliances. Reading this article (http://electrical-engineering-portal.com/what-is-hipot-testing-dielectric-strength-test) seems to confirm that.

I have not known anyone who has lost a piece of electronic equipment due to a transient unless lightning was involved.
One example of non-lightning issue is what I saw happen in my hometown (1980s in Brazil): a neutral ground interrupt fault, which raised the voltage of the phase wires to the point of internally arcing and damaging some of the consumer equipment and appliances. That was dangerous but fortunately there were no cases of electrocution.

Another problem that was caused by lightning and became very frequent were transients in telephone lines, which started to become more expensive when household modems came around. I have seen arcing in boards and DMMs while probing these lines at the wrong time.
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 15, 2017, 11:06:56 pm
You actually run into a mine field of issues on this, most mining operations (One's that are coal or ones which have been classified as "Gassy") in the US have to meet requirements for permissibility in certain mining area's(almost equivalent to Class 1 Div 1 in the NEC), only a few such meters meet that requirement (The southwire did not), though in the location it was discovered it wasn't required. The other requirement (not a legal one) is for it to be rugged, these meters in the mining environment are dropped in mud, have rocks fall on them etc.. If this isn't enough the equipment is always advancing as well, the power system at the "face"  (13800VLL is common) is typically moved once per week. In a nut shell it comes down to what equipment is available to use, that's the reason for the "Best practices" of measuring phase to ground ( The system is also resistive grounded - 25 Amps max current). Most equipment which could be used that would more adequately meet the voltage rating (Buying margin on the voltage) would also lack in the durability. It's a trade off, I will say if you search the MSHA website for electrical accidents very few, almost none, are due to the meter it's self failing, that I could fine anyway.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 16, 2017, 02:00:35 am
Part 2 showing a little more detail on the proximity problem.  For Part 3, I plan to run the continuity tests and then write some LabVIEW code to interface with the meter.  I had recently ran some tests on my UNI-T UT181A where I held the temperature somewhat constant with the inputs to the meter shorted and plotted the drift.  This was to compare the meter with various Fluke 289's that other members had collected the same data from. That thread may be found here:

https://www.eevblog.com/forum/beginners/is-my-new-fluke-289-multimeter-faulty/ (https://www.eevblog.com/forum/beginners/is-my-new-fluke-289-multimeter-faulty/)

I plan to run this same test with the Gossen. 

My plan is to give Gossen a couple of weeks to respond to the email I sent them on the 10th asking about the proximity problem.  I'm sorry to have to say that they have not even sent an acknowledgment of the email.     

Hope you enjoy the video.   

https://www.youtube.com/watch?v=wYuzFtoHMqg (https://www.youtube.com/watch?v=wYuzFtoHMqg)
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 16, 2017, 02:43:49 am
I don't have the same meter, but I can report that the Gossen MetraHit 30M, which reads down to 100nV doesn't behave like that at all. It only shows some minor fluctuation on the last digit.
The MetraHit 26S, with has a resolution of 10uV, is rock solid, to the last digit.
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 16, 2017, 03:12:35 am
Reminds me of the Apple iPhone 4 "Antenna Gate" debacle.
In addition to the email you sent them, send a link to this thread and the 2 YouTube videos you made. You may find you get a faster response as few companies want any negative comments or findings spread on the internet.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 16, 2017, 03:42:41 am
Reporting the fault in the German language should provide a quicker answer.
I doubt such a mV behavior would be acceptable to Gossen. That meter must be faulty, but we shall see.
mailto:Support.industrie@gossenmetrawatt.com
http://gossen.ofactory.biz/services/produkt-support/allgemeine-hinweise/ (http://gossen.ofactory.biz/services/produkt-support/allgemeine-hinweise/)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 16, 2017, 10:48:59 am
Reporting the fault in the German language should provide a quicker answer.
I doubt such a mV behavior would be acceptable to Gossen. That meter must be faulty, but we shall see.
mailto:Support.industrie@gossenmetrawatt.com
http://gossen.ofactory.biz/services/produkt-support/allgemeine-hinweise/ (http://gossen.ofactory.biz/services/produkt-support/allgemeine-hinweise/)

The best thing is to point them to the video.

Any German readers want to fill in the support form?

(I'm sure they'll understand English if I fill it in, but...  :-// )
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 16, 2017, 11:05:13 am
I can't imagine the thing isn't shielded inside. Maybe the shield isn't connected properly.

Take it apart and have a peek inside.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 16, 2017, 11:41:54 am
I can't imagine the thing isn't shielded inside. Maybe the shield isn't connected properly.

Take it apart and have a peek inside.

Removing the cover voids the warranty.  From watching Dave's video on the Energy, I suspect there are other latches and that is why he uses the screwdriver.  Maybe the meter broke when he pried it apart? I have no idea.  I asked.  I will pull one of them apart at some point and it would be good to know if there was a trick to getting it apart.   

The other problem with taking it apart is like we saw in one of Dave's recent mailbag videos were he was sent a box of brand new meters.  He does a quick teardown and then the meter does not work.  It raises questions if the meter was damaged during the teardown.  We have no idea. 

This meter (or another of the same model) will come apart once I have completed all of my basic tests.  I want it to be VERY clear to people that this is how the meter worked when I received it. 

https://www.eevblog.com/forum/blog/eevblog-173-gossen-metrahit-energy-multimeter-teardown/ (https://www.eevblog.com/forum/blog/eevblog-173-gossen-metrahit-energy-multimeter-teardown/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 16, 2017, 11:49:22 am
I don't have the same meter, but I can report that the Gossen MetraHit 30M, which reads down to 100nV doesn't behave like that at all. It only shows some minor fluctuation on the last digit.
The MetraHit 26S, with has a resolution of 10uV, is rock solid, to the last digit.

It would be nice to hear from someone with the exact same model to see if they see the same problem.   For now, I plan to just wait on Gossen while I work on some software to support it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 16, 2017, 11:58:24 am
Reminds me of the Apple iPhone 4 "Antenna Gate" debacle.
In addition to the email you sent them, send a link to this thread and the 2 YouTube videos you made. You may find you get a faster response as few companies want any negative comments or findings spread on the internet.

The only real problem I see so far is someone who is dealing with customers blocking their email for simple questions.  With Gossen now owning them, it really does fall in their court to address it.  I've seen other meters come in defective.  Granted, I buy some pretty low end products.  Give Gossen a chance to decode my email. 

Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 16, 2017, 12:30:40 pm
I can't imagine the thing isn't shielded inside. Maybe the shield isn't connected properly.

Take it apart and have a peek inside.

Removing the cover voids the warranty.  From watching Dave's video on the Energy, I suspect there are other latches and that is why he uses the screwdriver.  Maybe the meter broke when he pried it apart? I have no idea.  I asked.  I will pull one of them apart at some point and it would be good to know if there was a trick to getting it apart.   

The other problem with taking it apart is like we saw in one of Dave's recent mailbag videos were he was sent a box of brand new meters.  He does a quick teardown and then the meter does not work.  It raises questions if the meter was damaged during the teardown.  We have no idea. 

This meter (or another of the same model) will come apart once I have completed all of my basic tests.  I want it to be VERY clear to people that this is how the meter worked when I received it. 

https://www.eevblog.com/forum/blog/eevblog-173-gossen-metrahit-energy-multimeter-teardown/ (https://www.eevblog.com/forum/blog/eevblog-173-gossen-metrahit-energy-multimeter-teardown/)

I agree. I often wonder about that too. I see Mr. Jones take some equipment apart and poke around in there with a metal screwdriver, pointing out the various components, possibly scratching fine traces, and in the process perhaps damaging something BEFORE testing the product, and proceeding to call the item in question, "a heap of garbage" after discovering later it does not function properly. Case in point, the Global Specialties meter in one of the multimeter shootouts. It's not fair to a product to take it apart before testing it. Was it damaged before it arived? Not a very scientific way to test something...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 17, 2017, 11:39:13 am
Howardlong took the time to put a video together for me showing how the cover is removed.  He struggled at the same point at Dave but then shows the two internal latches.  This is going to be a big help in another week.

https://www.youtube.com/watch?v=IPru_A9NXyY (https://www.youtube.com/watch?v=IPru_A9NXyY)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 19, 2017, 11:38:20 am
Looking at the continuity feature and how to interface with the Gossen using it's built in Bluetooth interface.  I also attempt to compare the temperature drift of Gossen with my most temperature stable meter, the UNI-T UT181A.  Yes, that's right.  UNI-T nailed it on this.

https://www.youtube.com/watch?v=sZChenxYv04 (https://www.youtube.com/watch?v=sZChenxYv04)
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 19, 2017, 03:26:10 pm
Comparing a top of the range 300,000 count meter to a 40,000 count middle of the road Chinese DMM.  ::)
Wait till you get hold of a 1,200,000 count Gossen 30M, for something really juicy! (16hr battery life, sipping 100mA on idle)
Bluetooth here is meant to be used for short periods, to observe readings at a distance (Android app), not 24hr logging.
The meter has a 300,000 data point internal memory for that task and external power connector, if required.
The final log can then be quickly uploaded to the computer via BT, USB or USB BT.

Influence of temperature on readings outside of the usual 21~25C band is documented:
Was the meter within specs?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 20, 2017, 05:27:51 pm
The 30M was discontinued so I doubt I would ever do anything with one.  The Ultra is what they list for its successor.

It is interesting how temperature effects the Ultra compared with the Chinese made UT181A.  I think the 181A had about half the battery life after running it for 18 hours.  One thing I did not mention in the video that may not have been clear.  I was sampling both meters every 2 seconds.  Checking the CEM DD-9939, it sends data once a second by default. 

This thread is a meter review and as such, looks at all the features of the UT71D. What I use the meter for is irrelevant.

Good point. I am not suggesting how anyone use the meter.  This Gossen may make a good meter for someone who never needs to use the relative mode or never needs to be near it. Or at least be aware of I've shown in the video at least 12mV of error.  I guess you could run it remote from the Bluetooth interface if it only needs to run for a short time.  But again, to your point that's all irrelevant.  I am just showing the data I collect.   

I am not sure if the meter meets spec of not.  If Gossen ever decides to respond, maybe they could enlighten us.  Holding the temperature within a couple of degrees, 12mV of error on the 300mV range is not real great no matter the excuse.  I won't disagree that the meters I use for a comparison may very well be considered middle of the road, they are certainly more stable when it comes to getting near the meter or running a sweep on them. 

For the few of you who are not interested is seeing the Gossen get ran, the best thing to do is just don't watch.  I'm certainly not on a witch hunt.  For those of you who voted to see a Gossen ran, I hope you are enjoying it.

There's more to come.  I have a few more non-destructive tests I want to do, then we will have a look at the inside and maybe do a little reverse engineering.   As always, if you have a test you would like to see ran, feel free to ask.  Often people will ask a question about a meter I looked at not realizing that very few meters survive or are repairable. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 21, 2017, 02:29:30 am
Part 4

https://www.youtube.com/watch?v=yD-q6bq7mlE (https://www.youtube.com/watch?v=yD-q6bq7mlE)
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 21, 2017, 03:28:17 am
I've gotta say I'm surprised at the Gossen so far (Not that I'd heard of them before EEVBlog), they are held in high esteem but it seems like from these tests its nothing special.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 21, 2017, 04:25:15 am
Read the manual. None of the Gossens have a Peak mode, except for the Gossen Energy. Testing a feature that doesn't exist.  :-DD
Why don't you test the Auto Hold mode of the Brymen?
Not on a witch hunt? When the pigs fly.

No meter does everything. That's why it is important to read the spec sheet and have a range of meters to cover all bases, or at least cater for your limited needs.
I think a Peak mode is useful, if only to work out the crest factor, but for some reason, Gossen thinks differently.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 21, 2017, 05:41:29 am
I've gotta say I'm surprised at the Gossen so far (Not that I'd heard of them before EEVBlog), they are held in high esteem but it seems like from these tests its nothing special.

these "tests" are purely for entertainment... I wouldn't base any decisions on them whatsoever...
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on May 21, 2017, 04:40:02 pm
these "tests" are purely for entertainment... I wouldn't base any decisions on them whatsoever...

I disagree. Anyway, feel free to propose your tests.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 21, 2017, 06:46:20 pm
these "tests" are purely for entertainment... I wouldn't base any decisions on them whatsoever...

I disagree. Anyway, feel free to propose your tests.
Same here. When you see the meters failing at somewhat midrange through the voltages, the interpretation one can make of Joe's tests leave a lot of wiggle room in terms of comparison. However, when one fails at the edges it gives you much more to think - especially when a random unit fails with a simple spark.
Title: Re: Handheld meter electrical robustness testing.
Post by: jpb on May 21, 2017, 07:24:57 pm
Read the manual. None of the Gossens have a Peak mode, except for the Gossen Energy. Testing a feature that doesn't exist.  :-DD
I think a Peak mode is useful, if only to work out the crest factor, but for some reason, Gossen thinks differently.
The Gossen does have a Rapid Momentary Value Acquisition mode with data store so can capture (close to) peaks I guess but not a simple peak mode.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 22, 2017, 11:17:03 am
That would be a feature worth testing. Seems unique to the Ultra and the Energy. Not a proper Peak mode, but may be useful in some circumstances. The Energy DMM has both features. It even calculates the crest factor.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 22, 2017, 08:16:50 pm
I find Joe's tests very informative.
The tests are applied fairly to each product and give a reasonable view of each meter tested.
I think he should be applauded for the time,effort and MONEY he puts into this project.

THANK YOU JOE  :clap:
3DB
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 24, 2017, 05:16:56 am
Part 5 of the review for the Metrahit Ultra.   

https://www.youtube.com/watch?v=YPzbjxNB-fc (https://www.youtube.com/watch?v=YPzbjxNB-fc)
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on May 24, 2017, 05:42:04 am
So what's next? The Gossen is more susceptible to ionizing radiation? More inaccurate in low-gravity environments? Unstable readings while being accelerated?

Joe don't like the Gossen  :-DD

Lots of fun.
Title: Re: Handheld meter electrical robustness testing.
Post by: Paul Moir on May 24, 2017, 05:45:17 am
Would it kill them to pulse the relay at power on?
Title: Re: Handheld meter electrical robustness testing.
Post by: ProBang2 on May 24, 2017, 06:33:21 am
Sorry, the DMM works correct.

It is set to "Auto Power off" after 10 Minutes.
For logging it can be deactivated in this menu.
Or set to a different time.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=318132;image)

Aside of that:
Clearly it has big problems with shielding and a lack of customer service...   :palm: |O
Title: Re: Handheld meter electrical robustness testing.
Post by: mmagin on May 24, 2017, 06:49:31 am
So thats why nobody else uses relays in handheld meters :P
It's certainly conceivable that in industrial use similar magnetic fields sould be experienced.

Really enjoying the extensive review.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2017, 08:31:03 am
So thats why nobody else uses relays in handheld meters :P
It's certainly conceivable that in industrial use similar magnetic fields sould be experienced.

That would be dangerous in a lot more situations, eg. if you threw it in the back of a pickup then drove across the farm*. :popcorn:

A couple of tests:
1: Does the reading flip if you connect it up to the mains AC then slap it around a bit.
2: Does it combust if you connect it to mains AC then use the tape eraser on it?

(*) Germans would only ever throw it in the back of an S-class Mercedes so I can see how they'd miss that one during the design phase.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on May 24, 2017, 09:01:47 am
I wonder if you can flip the relay into the 'wrong' state by bashing the meter.

That is exactly why bistable relays are a no go in certain high vibration equipment.
If you find the right force vector direction, even a not so strong tap on relay will do..

All mechanical relay are sensitive, but regular ones at least auto reset to right position after the influence is removed.
But if you put that tape eraser nearby any smaller signal relay, it will go crazy..
Reed relay would have real fun ....That is why they many of them are magnetically shielded.


Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 24, 2017, 09:03:31 am
Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 
 
Electromagnetic Compatibility (EMC)
Interference emission EN 610326-1:2006, class B
Interference immunity EN 610326-1:2006 EN 610326-2-1:2006

Americans can't make well engineered meters either. The Fluke 185 and 867B, just to name a few, also have relays.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 24, 2017, 09:07:19 am
Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 
 
 
Electromagnetic Compatibility (EMC)
Interference emission EN 610326-1:2006, class B
Interference immunity EN 610326-1:2006 EN 610326-2-1:2006

Americans can't make meters either, the Fluke 185 and 867B, just to name a few, also have relays.


:-D
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2017, 09:54:27 am
Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 

It would have to be a hell of a magnetic field to flip the relay from more than foot or so, yes.

Americans can't make well engineered meters either. The Fluke 185 and 867B, just to name a few, also have relays.

But ... does Fluke pulse the relay at power-on to make sure it's in the correct state?

If so, that's a huge difference. Arriving at a site and not knowing if the reading will be correct because you hit a pothole on the way over is slightly worrying.  If I owned one of those and worked on remote sides I'd be switching to Ohms mode every single time from now on. Either that or switch to the industry standard Fluke 87 or 28 (actually more likely than switching to Ohms mode every time).

We need joe bash the meter to find out how easy it is to flip the relay manually.

One problem: He likes to quantify things and "slapping" is unscientific. I can't wait to see the machine he invents for this.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 24, 2017, 10:17:05 am
Scaremongering again.
The meter passed all electromagnetic requirements for multimeters.
Just don't take it with you for your next MRI scan and mind those tooth fillings too... 
 
Electromagnetic Compatibility (EMC)
Interference emission EN 610326-1:2006, class B
Interference immunity EN 610326-1:2006 EN 610326-2-1:2006

Americans can't make well engineered meters either. The Fluke 185 and 867B, just to name a few, also have relays.

WTF does Germans /Americans have to do with it ?   :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 24, 2017, 10:24:59 am
No pulsing on the Flukes.

NAIS relay:
g force:
50g functional   100g destructive
Vibrations:
10-55Hz 3.3mmx2 amplitude functional
10-55Hz 5.0mmx2 amplitude destructive

Pothole won't do it. Empire State building maybe.
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 24, 2017, 11:02:42 am
I wonder what it would do with a strong DC field. Very high magnetic field strength electromagnets are used heavily in the mining industries for separation of metallic contamination (I'm supposing this is also used in several other industries for the same reason- but mining is the only one I have experience with).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 24, 2017, 12:25:44 pm
I wonder what it would do with a strong DC field. Very high magnetic field strength electromagnets are used heavily in the mining industries for separation of metallic contamination (I'm supposing this is also used in several other industries for the same reason- but mining is the only one I have experience with).

https://www.youtube.com/watch?v=u0AOIQxXKh4 (https://www.youtube.com/watch?v=u0AOIQxXKh4)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2017, 12:30:49 pm
So... don't ever put it in a toolbox near anything magnetic.

I'm with joe, this is a dangerous, recall-worthy problem.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 24, 2017, 12:53:27 pm
So... don't ever put it in a toolbox near anything magnetic.

I'm with joe, this is a dangerous, recall-worthy problem.


more scaremongering...


:palm:

Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 24, 2017, 01:27:15 pm
That video is very interesting, the relay it's self doesn't bother me at all, the fact that it appears to be latching with no reset or check for failure..does.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 24, 2017, 02:20:12 pm
So... don't ever put it in a toolbox near anything magnetic.

I'm with joe, this is a dangerous, recall-worthy problem.
Me too.

Some might say it couldn't happen on the bench, yeah right.
Who hasn't had a conventional moving coil speaker on the bench ?

Oh yeah, we've all moved past them to those fancy electrostatic units.....whoops we've still got a problem Houston.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 24, 2017, 02:39:58 pm
Relays can be badly affected in strong magnetic fields, as warned by manufacturers. So can Rolex watches.
Just keep your neodymium magnets far away from expensive tools.
Leaving the rubber boot on the meter should help minimize careless interaction in the toolbox.

To stay out of trouble, always follow the old adage of measuring known voltages, before testing unknown ones.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 24, 2017, 04:07:22 pm
IMHO these relays should be set to a defined condition when the meter is switched on (initialised / during post).
I'm assuming that they are the bistable type with two coils.
I bet if this meter were made by UNI-T or some other chinese company then everyone would be   :blah:
about how terrible it was.

3DB.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 24, 2017, 04:28:56 pm
Yeah. Gossen and Metrawatt have only been making meters since 1906. A real bunch of amateurs.
As for Fluke putting relays in their multimeters! Disgusting!
Let Brymen and Uni-T show them how it's done. No relays here, siree...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 24, 2017, 04:33:01 pm
You could procure a genuine $70 GMW magnet to go with this meter. 

https://www.amazon.com/Gossen-Metrawatt-Z117A-Magnetic-Holder/dp/B0128DNNDC (https://www.amazon.com/Gossen-Metrawatt-Z117A-Magnetic-Holder/dp/B0128DNNDC)

Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 24, 2017, 04:43:21 pm
They only work with the rubber boot on and may not be as strong as the one you played with.
If there is a magnetic interaction with the holder, then I'll agree that Gossen should at least warn their customers.

The Fluke 185 relay is also affected by a strong neodymium magnet held to the back of the meter, but only if taken out of its boot.
The 8 pound magnet at the tip of my magnetic wand had no effect.
The Fluke 867B case is so big, only the LHC may affect it in any way.

https://www.amazon.com/Magnetic-Telescoping-Retriever-Telescopic-Retrieving/dp/B0175B3VRU (https://www.amazon.com/Magnetic-Telescoping-Retriever-Telescopic-Retrieving/dp/B0175B3VRU)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 24, 2017, 05:31:04 pm
No way I would cough up $70 on the OEM part just so I could brag I have a real GSM hanger to go with my GSM meter.  But I do have one that came with that low end CEM meter. 

https://www.youtube.com/watch?v=COuCsWDoI9E (https://www.youtube.com/watch?v=COuCsWDoI9E)
Title: Re: Handheld meter electrical robustness testing.
Post by: The Soulman on May 24, 2017, 05:52:59 pm
 :palm: Told you to get one of the entry level models, pretty sure those would stand up to any of these tests..
Unfortunately this higher end model seems a bit over engineered.  |O
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 24, 2017, 06:09:21 pm
Gossen engineer: 'Ha, but you didn't use our special low tesla samarium–cobalt holder'  ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2017, 07:17:28 pm
Relays can be badly affected in strong magnetic fields, as warned by manufacturers. So can Rolex watches.
Just keep your neodymium magnets far away from expensive tools.

That's easy to say, but I expect to keep my Rolex away from magnets. I don't expect that from a multimeter.

It's probably just a firmware fix - pulse the relay at power on but people need the option to send their meters in for update/replacement IMHO.

To stay out of trouble, always follow the old adage of measuring known voltages, before testing unknown ones.

That's easy to say. The point is that this behavior is totally unexpected. Multimeters don't normally do things like this.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2017, 07:19:00 pm
You could procure a genuine $70 GMW magnet to go with this meter. 

https://www.amazon.com/Gossen-Metrawatt-Z117A-Magnetic-Holder/dp/B0128DNNDC (https://www.amazon.com/Gossen-Metrawatt-Z117A-Magnetic-Holder/dp/B0128DNNDC)

I wonder if that magnet is strong enough to do it.  :popcorn:

(I imagine it's quite strong...)

Edit: Oh, I just watched the latest video...  :-DD

"Gossen, we have a problem!"
Title: Re: Handheld meter electrical robustness testing.
Post by: serggio on May 24, 2017, 07:58:38 pm
Joe, when Fluke 287 wil be on your table under knife?  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 24, 2017, 08:09:57 pm
Take the brand name fanboy element out of the equation, pretend the meters are hidden in brown paper bags, and it certainly appears there are some negative issues with this premium meter especially compared to some other lower priced meters. Thanks to Joe for his time and discoveries, don't see many if anyone attempting these kind of tests.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 24, 2017, 09:00:24 pm
They only work with the rubber boot on and may not be as strong as the one you played with.
If there is a magnetic interaction with the holder, then I'll agree that Gossen should at least warn their customers.

The Fluke 185 relay is also affected by a strong neodymium magnet held to the back of the meter, but only if taken out of its boot.
The 8 pound magnet at the tip of my magnetic wand had no effect.
The Fluke 867B case is so big, only the LHC may affect it in any way.

https://www.amazon.com/Magnetic-Telescoping-Retriever-Telescopic-Retrieving/dp/B0175B3VRU (https://www.amazon.com/Magnetic-Telescoping-Retriever-Telescopic-Retrieving/dp/B0175B3VRU)

When you remove the magnet and power off the meter.What happens when you power it on ?

3DB
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 24, 2017, 09:32:45 pm
When you remove the magnet and power off the meter.What happens when you power it on ?

Nothing. It stays "broken" until you do something that clicks the relay, eg. select Ohms range.

Watch the video:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216462/#msg1216462 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216462/#msg1216462)
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 24, 2017, 09:37:17 pm
When you remove the magnet and power off the meter.What happens when you power it on ?

Nothing. It stays "broken" until you do something that clicks the relay, eg. select Ohms range.

Watch the video:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216462/#msg1216462 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216462/#msg1216462)

I believe he was referring to the Fluke meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 24, 2017, 10:14:26 pm
When you remove the magnet and power off the meter.What happens when you power it on ?

Nothing. It stays "broken" until you do something that clicks the relay, eg. select Ohms range.

Watch the video:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216462/#msg1216462 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216462/#msg1216462)

@Fungus
My question related to the Fluke. Perhaps I should have been clearer.
I watched the video hours ago.
I'd like to know if the Fluke performs correctly when it's powered up.

3DB
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on May 24, 2017, 10:26:19 pm
Problem is that nowadays, premium  brands in T&M think they are Apple, and not HP or Tektronix of old..
They think premium brand means premium design, looks, marketing, "coolness factor"  put over product that is decent, but not more than that. We seem to think it means premium quality, measurements, protection and such... But it usually means "touchscreen annotations " (like new R&S scope) and such gimmicks.. That "feature" is free... Protocol triggers and decode (reason why I would buy the darn scope!!) are OPTIONAL... 

63USD magnetic holder for Gossen-Metrawatt meters... that  works exactly like 4.5€ Brymen holder (it's a freaking piece of plastic with a magnet!!!). 
Rebadged Taiwanese scope probes for three time the price....
Array DC loads rebadged by Gossen for 2-3 times the price....

I have no problem buying expensive quality.. I just don't like expensive bullshit...

And Keysight, Gossen, Fluke and all bigo ones.... none of them are sacred cows... I don't necessarily agree with every test Joe does, or even his conclusions sometimes.. But I love his irreverence and lack of idolatry.... Premium manufacturers are not faultless, and us being critical to them, instead running sorts of cults that worship certain brands, is good.
It is good to us (better products for us) , it is good for them ( we keep them honest ) in a long run.... And it is even better for second tier manufacturers and us.. It makes them try harder...And give us better affordable products...

I do not want to defend Joe's "crusade" on the Gossen meter ( I think he does a bit of drama on purpose.. It's how you stir up the people ), but I agree with him on general principle :
If I pay for a handheld as much as for a good 6.5 Digit Benchtop meter, I want it to be better, more robust and superior in every TECHNICAL aspect to a Brymen or whatever else out there.. I want it to have Mu metal shield, 2ppm/C stable reference, etc, etc...  It has to be an overkill on specs..
Otherwise why on earth would I buy it... If it's not actually better?
 
For the price you can buy FLUKE 87V AND Brymen 869S ... Or Brymen 869S AND FLUKE 289 ...  And all three of those are very good... And will do the task of measuring at least as good...

My 2c and million words... Sorry for verbosity..
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 24, 2017, 11:37:03 pm
Well, when you get reviewers of test gear (including Dave) spending time ranting about how "cheap" or "toyish" an equipment looks, you end up amplifying the feel that a teat gear has to also score high on this criteria - the manufacturers will pay attention to the reactions, given this may get some impulse buy, especially on the low-end.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 25, 2017, 12:30:06 am
Well, when you get reviewers of test gear (including Dave) spending time ranting about how "cheap" or "toyish" an equipment looks, you end up amplifying the feel that a teat gear has to also score high on this criteria - the manufacturers will pay attention to the reactions, given this may get some impulse buy, especially on the low-end.

IF that's the case then they should be FIRED.
Fluke,Gossen,HP,Keithley,R&S etc gained their reputation by creating great test gear.
Whilst they were commercially aware I believe these companies also pursued measurement excellence.
A fat cat corporation can only live for so long on it's reputation.
New players who are hungry and who have the same ethos as the HP's of old will eventually grab market share at the low end,get better and move up the food chain.
I think Siglent may be such a company.

P.S. Should I mention Japan and motorbikes  ;D

3DB

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 25, 2017, 12:37:17 am
Well, when you get reviewers of test gear (including Dave) spending time ranting about how "cheap" or "toyish" an equipment looks, you end up amplifying the feel that a teat gear has to also score high on this criteria

These days a student can knock out a dozen CAD renderings before lunch so there's no real reason why it has to score low, not at any price point.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 01:14:40 am
Just to make it perfectly clear,  with the rubber case on, I can toggle the relay/s with the included Extech magnetic strap I showed in the last video with no problems.  Also, if that strap were installed on this meter it can easily reach that area of the meter.   

And because someone asked, I did remove the batteries in an attempt to reset the meter as well.  As expected, a bust.

2N3055,  obviously I agree about the cost of the magnetic strap.  I think the cost of the software and cable were $450.

And Keysight, Gossen, Fluke and all bigo ones.... none of them are sacred cows... I don't necessarily agree with every test Joe does, or even his conclusions sometimes.. But I love his irreverence and lack of idolatry.... Premium manufacturers are not faultless, and us being critical to them, instead running sorts of cults that worship certain brands, is good.
It is good to us (better products for us) , it is good for them ( we keep them honest ) in a long run.... And it is even better for second tier manufacturers and us.. It makes them try harder...And give us better affordable products...

I agree that no brands are sacred.  If I found something I liked better than the Brymen, I would own it and talk about it.  The testing being what it is, is bound to cause people to interpret the results differently or not agree on the test methods in general.  It's new territory.  If it were common practice, I would not be doing it.   I am fine with that.   It's your next statement that comes as a bit of a pleasant surprise.  I get called out a fair amount for being biased toward one brand or another.  It's refreshing when someone sees it otherwise. Thanks. 

I do not want to defend Joe's "crusade" on the Gossen meter ( I think he does a bit of drama on purpose.. It's how you stir up the people ), but I agree with him on general principle :
If I pay for a handheld as much as for a good 6.5 Digit Benchtop meter, I want it to be better, more robust and superior in every TECHNICAL aspect to a Brymen or whatever else out there.. I want it to have Mu metal shield, 2ppm/C stable reference, etc, etc...  It has to an overkill on specs..
Otherwise why on earth would I buy it... If it's not actually better?
 
For the price you can buy FLUKE 87V AND Brymen 869S ... Or Brymen 869S AND FLUKE 289 ...  And all three of those are very good... And will do the task of measuring at least as good...

My 2c and million words... Sorry for verbosity..

Perhaps ego?  Maybe just to see how it was designed and constructed or how robust it is?  Maybe you started a poll and it was voted on?   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 01:34:29 am
P.S. Should I mention Japan and motorbikes  ;D
3DB

Just bikes in general are always a good topic.  The faster / quicker, the better!
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 25, 2017, 01:53:36 am
P.S. Should I mention Japan and motorbikes  ;D
3DB

Just bikes in general are always a good topic.  The faster / quicker, the better!

Around these parts we call motorcycle riders "organ donors."
I'd rather take my chances poking around in a 480V 3ph panel with a DT830 multimeter... 
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 25, 2017, 06:50:00 am
They only work with the rubber boot on and may not be as strong as the one you played with.
If there is a magnetic interaction with the holder, then I'll agree that Gossen should at least warn their customers.

The Fluke 185 relay is also affected by a strong neodymium magnet held to the back of the meter, but only if taken out of its boot.
The 8 pound magnet at the tip of my magnetic wand had no effect.
The Fluke 867B case is so big, only the LHC may affect it in any way.

https://www.amazon.com/Magnetic-Telescoping-Retriever-Telescopic-Retrieving/dp/B0175B3VRU (https://www.amazon.com/Magnetic-Telescoping-Retriever-Telescopic-Retrieving/dp/B0175B3VRU)

When you remove the magnet and power off the meter.What happens when you power it on ?

3DB

Without any input, I can change the auto ranging from mV to V and vice versa at will, by reversing the polarity of the magnet.
On restart, the auto ranging click back to the correct mV range.
With mains connected, the relay clicks back to the correct range too.
With mains connected, auto ranging can be changed with the magnet from 500V to 1000V, which then shows an erroneous OL.

I couldn't find a scenario where the meter would display a low voltage with mains connected.
I've been using very strong double stacked cylindrical neodymium magnets.

So the Fluke seems reasonably safe.

Morale of the story: Don't use a magnetic holder if your meter is equipped with relays. Doh!
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 25, 2017, 07:21:33 am
Gossen is well aware of the interaction, warns about it and lists the meters affected:

https://www.gossenmetrawatt.com/resources/tt/hitclip/hit-clip-ia_dgb.pdf (https://www.gossenmetrawatt.com/resources/tt/hitclip/hit-clip-ia_dgb.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 25, 2017, 08:05:06 am
Gossen is well aware of the interaction, warns about it and lists the meters affected:

That says "during operation".

There's no mention of transport or that it can get stuck in a "wrong" state which isn't cleared at power-on.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 25, 2017, 09:09:15 am
Hard to think Gossen wouldn't have checked the meter for that eventuality.
If it does happen with their holder too, and all indications are that it may, they should advise customers to keep magnets away from the meter until they update the software, to make sure the relay is on the right connection at power up.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 25, 2017, 10:20:09 am
P.S. Should I mention Japan and motorbikes  ;D
3DB

Just bikes in general are always a good topic.  The faster / quicker, the better!
 

Around these parts we call motorcycle riders "organ donors."
I'd rather take my chances poking around in a 480V 3ph panel with a DT830 multimeter...

My point is that Japan started from nothing and became a MAJOR player in the Motorbike and car industry.
The established companies were complacent and didn't see this until it was to late.

 :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 10:30:46 am
Hard to think Gossen wouldn't have checked the meter for that eventuality.
If it does happen with their holder too, and all indications are that it may, they should advise customers to keep magnets away from the meter until they update the software, to make sure the relay is on the right connection at power up.

All I need to do is pull the meter away from what ever it is strapped to, have that strap bounce around while I move the meter to the new location and not power cycle the meter.  There is no way I can see something as simple as pulsing the relays on start up as being a solution.  It may be just a quick to use the ohms mode to reset versus a power cycle each time the meter was setup.  IMO, if you are going to use them, they better gave feedback or shielding to prevent it.  Even with feedback, if the meter could be in an unsafe condition from switching there is no way I would allow for it.  By the time the meter detected the fault and corrected for it, the damage may already have been done. 

IMO, the standards should account for this.  That's a very large body and I get the feeling moves very slow.   And the fact you claim Gossen is 100ish years old with all this experience makes it worse.  They should know better.  There is no excuse on their part for releasing a design like this into the public. 

If you would rather a nice fluffy review, Dave's on the  Energy is pretty good.  Gossen provides a link to it from their website.  You are not going to see them linking my review any time soon. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 10:42:13 am
My point is that Japan started from nothing and became a MAJOR player in the Motorbike and car industry.
The established companies were complacent and didn't see this until it was to late.
 :palm:

And they continue to make them quicker and faster!!   :-+ :-+  Most of what I see on the road now are HDs.  Never underestimate the power of good marketing and the human ego vs technology.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 25, 2017, 10:44:26 am
It may be just a quick to use the ohms mode to reset versus a power cycle each time the meter was setup.

One of those is unsellable. People would laugh at you if you told them to switch to Ohms mode before every reading.

The 'solution' is magnetic shielding and pulse the relay whenever you select a range that depends on it.


PS: Google tells me they manufacture magnetically shielded relays with metal cases especially for applications like this. So much for Gossen's "100 years of experience".  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 10:53:29 am
It may be just a quick to use the ohms mode to reset versus a power cycle each time the meter was setup.

One of those is unsellable. People would laugh at you if you told them to switch to Ohms mode before every reading.

The 'solution' is magnetic shielding and pulse the relay whenever you select a range that depends on it.


PS: Google tells me they manufacture magnetically shielded relays with metal cases especially for applications like this. So much for Gossen's "100 years of experience".  :popcorn:

People would laugh if I told them they had to power cycle the meter between readings as well.   Of course if people knew what a POS the meter is for the $850 they spent on it, they would not be laughing anymore. 

Again, if you are in the middle of using the meter and it changes states, if this makes a hazardous condition I would say pulsing before hand does not solve it.  Don't address the symptom, go for the root problem.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 25, 2017, 10:59:27 am
Have you tried whacking it yet?

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 11:18:38 am
Have you tried whacking it yet?

Whacking is not very scientific.  Maybe someone here has a vibration table and would make up a test jig for one.  Anyone who has done this sort of work knows the problems.  It's not something the datasheets are going to tell you. 

There is a lot more testing to be done before I would consider some sort of mechanical shock test and that Extech strap should be enough to raise a concern. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 25, 2017, 11:22:51 am
Have you tried whacking it yet?

Whacking is not very scientific.

Exactly what I predicted (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216365/#msg1216365) you'd say (on the previous page).

It's fun though, and might give you an idea of how easy/difficult it is.  :popcorn:

I'd give it a few sharp taps with a little hammer from all six sides.

(yeah, normally it would have rubber if it was transported a lot, but this is an 'informal' test)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 25, 2017, 11:27:26 am
Have you tried whacking it yet?

Whacking is not very scientific.

Exactly what I predicted (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1216365/#msg1216365) you'd say (on the previous page).

It's fun though, and might give you an idea of how easy/difficult it is.  :popcorn:

One problem: He likes to quantify things and "slapping" is unscientific. I can't wait to see the machine he invents for this.  :popcorn:

I wonder how my wife would feel about setting up small environmental chamber with a vibration table in the living room. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2017, 10:13:26 pm
Looks like the low end company is stepping up and doing the right thing with a recall over a similar problem as this Gossen.   Gossen's technique is just ignore it's customers.  Really sad. 

https://www.cpsc.gov/Recalls/2017/extech-recalls-digital-clamp-meters (https://www.cpsc.gov/Recalls/2017/extech-recalls-digital-clamp-meters)
Title: Re: Handheld meter electrical robustness testing.
Post by: gslick on May 26, 2017, 10:21:28 pm
Looks like the low end company is stepping up and doing the right thing with a recall over a similar problem as this Gossen.   Gossen's technique is just ignore it's customers.  Really sad. 

https://www.cpsc.gov/Recalls/2017/extech-recalls-digital-clamp-meters (https://www.cpsc.gov/Recalls/2017/extech-recalls-digital-clamp-meters)

http://www.extech.com/display/?id=16536 (http://www.extech.com/display/?id=16536)

This recall stems from consumer reports that the clamp meter’s input terminal screws are loosening. The loosened screws can create an open circuit at the test lead input jack of the meter, causing the meters to give inaccurate voltage readings. An incorrect reading can cause the user to falsely believe that the electrical power of the test subject is low or off, in turn, posing an electrocution hazard.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2017, 10:36:40 pm
http://incompliancemag.com/extech-recalls-digital-clamp-meters/?utm_campaign=Weekly%20Recall%20Alert&utm_source=hs_email&utm_medium=email&utm_content=52443488&_hsenc=p2ANqtz-_V2Rd_O2RVii4mNlz7ZkIy4dQLx8y6795z8tHXlzsto-qNahTXzZOOTQInsy-QVAnS-v-iquHlNVee6rSKZPX5Mnisbw&_hsmi=52443488 (http://incompliancemag.com/extech-recalls-digital-clamp-meters/?utm_campaign=Weekly%20Recall%20Alert&utm_source=hs_email&utm_medium=email&utm_content=52443488&_hsenc=p2ANqtz-_V2Rd_O2RVii4mNlz7ZkIy4dQLx8y6795z8tHXlzsto-qNahTXzZOOTQInsy-QVAnS-v-iquHlNVee6rSKZPX5Mnisbw&_hsmi=52443488)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2017, 10:38:34 pm
I guess if someone dies or gets injured, then you notify  https://www.saferproducts.gov/ (https://www.saferproducts.gov/)     
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 26, 2017, 11:06:32 pm
Have you every heard anything from Gossen? For the price of this meter you would think customer support would be top notch.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2017, 11:17:08 pm
Have you every heard anything from Gossen? For the price of this meter you would think customer support would be top notch.

They have not. Maybe they forward all US emails to Dranetz.   They may still have my email blocked after I asked them about alignment. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 07:28:19 am
Quote
One problem: He likes to quantify things and "slapping" is unscientific. I can't wait to see the machine he invents for this.  :popcorn:
I wonder how my wife would feel about setting up small environmental chamber with a vibration table in the living room. 

A vibration table lets you accurately compare meters against other meters but it doesn't give you any feel for how easy it is to do the real world. For that you need to slap it around a bit.

Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 27, 2017, 08:13:06 am
Quote
One problem: He likes to quantify things and "slapping" is unscientific. I can't wait to see the machine he invents for this.  :popcorn:
I wonder how my wife would feel about setting up small environmental chamber with a vibration table in the living room. 

A vibration table lets you accurately compare meters against other models but it doesn't give you any feel for how easy it is to do the real world. For that you need to slap it around a bit.


throw 'em in the dryer machine...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 08:17:40 am
throw 'em in the dryer machine...

FedEx it to yourself.  :scared:

Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 27, 2017, 08:29:03 am
throw 'em in the dryer machine...

FedEx it to yourself.  :scared:

and write " FedEx drivers suck!" on the package in large purple letters, before you send it...  :-)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 12:07:41 pm
Quote
One problem: He likes to quantify things and "slapping" is unscientific. I can't wait to see the machine he invents for this.  :popcorn:
I wonder how my wife would feel about setting up small environmental chamber with a vibration table in the living room. 

A vibration table lets you accurately compare meters against other meters but it doesn't give you any feel for how easy it is to do the real world. For that you need to slap it around a bit.

Equipment like this is exactly how we get reproducible tests.   First define what "real world" is, then we test is.  For you, real world apparently means slapping the meter around.  I think to Dave it means dropping it from the dam or swimming with it.   The meter survived shipment to my house across the ocean.  I would guess it saw some pretty big changes in temperature, pressure and vibration.  Relays were in their correct state.  Maybe that is real world?

Almost forgot, I did bang on it pretty good with a screw driver in various locations.  Not something normally I would expect in the real world, but when you have a POS product such as this one, I could see it even going airborne in the lab.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 01:14:55 pm
The meter survived shipment to my house across the ocean.  I would guess it saw some pretty big changes in temperature, pressure and vibration.
Welll ... Oceans don't really vibrate or shake. It's more heave and roll.

I already gave the example of driving across a farm with the meter loose in the back of a pickup truck. That's real world, it could happen.

What I"m really talking about is getting a finger in the air feel for where the bar should be set. eg. If you've tapped it for a few minutes from all directions with a little hammer and failed to move the relay then it's obviously not easy to move and you'll need a powerful vibration table. It could also go the other way and the relay shifts with the first tap - not much of a table needed!

Whichever it goes, it's information. I don't see why it should be dismissed just because it's not scientifically rigorous.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 01:47:39 pm
I assume based on value that it was sent by air.  This is why I mentioned the temperatures and pressures.

Sure, I could drop it from my roof to the concrete below and that would be real world.  I could drop it out the window of my car, that would be real world.  I could even hit it with a "little hammer" which in my case would be a 10lb sledge.   

The problem is how do you quantify and reproduce it?  IMO such tests are pointless to attempt at the hobby level.  At best a drop test could be performed but I really have no interest in such things which is why I never do it.  I'll leave this to the Dave's of the world. 

Like I said, I know the meter made it to my home from Germany without changing states or at least showed up in the correct state.  That's real world testing.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 03:11:39 pm
The problem is how do you quantify and reproduce it?

None of these worries stopped you from waving an uncalibrated tape eraser near it to see whether it had an effect or not. You didn't measure the strength of the strap magnet or precisely measure the distance to the meter, you just held it up to the camera and said "about that far".

How is tapping it from all directions any less scientific than that? :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 04:06:12 pm
That is correct.  It also did not stop me from tapping on it with a screwdriver to see if there was any effect, which there was not.  In my home electronic hobbies I actually do have magnetic fields around (like the tape eraser) but it would be rare that I would ever tap on test equipment or drop it which is really why I don't care about it.   

The half cycle line test, investigating the shunts, RF immunity, emissions, high frequency high voltage....  all fall into this unscientific testing.  Because I have no way to quantify the results, they are not something I keep metrics on.   

I am not running these tests for you personally or the general public.  I run them for myself and share the results. If you are looking for someone to drop, beat on or swim with them, Dave is your guy.  Another option would be for you to step up, buy this same meter and show us how it should be tested. 

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 04:13:12 pm
I'm not going to buy an $800 for a meter just to do that test but it might be interesting to get a couple of transparent-cased relays with similar G-ratings and tap them to get an idea of what the G-ratings translate to in tangible terms.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 27, 2017, 04:32:54 pm
A one meter fall on a hard surface is likely to damage the relays, especially if the meter is dropped without its rubber boot.
Drop face first on concrete and feel the effect of 100g.  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 04:58:24 pm
Yep, G force numbers look big on paper but a sharp tap can easily produce hundreds of Gs for an instant.

Real engineers carry their meters in huge foam padded cases and only take them out on site.

What would you do if you dropped your meter as you took it out of the case on site? Say 'sorry I can't use that' and come back next day?  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 05:02:31 pm
I'm not going to buy an $800 for a meter just to do that test but it might be interesting to get a couple of transparent-cased relays with similar G-ratings and tap them to get an idea of what the G-ratings translate to in tangible terms.
You should not expect people to do something you are not willing to do yourself.  It's fine to ask but don't expect it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 05:06:56 pm
A one meter fall on a hard surface is likely to damage the relays, especially if the meter is dropped without its rubber boot.
Drop face first on concrete and feel the effect of 100g.  >:D

I will take your word for it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 05:09:22 pm
They make stickers for parcels that can be used for tests like this.

http://shockwatch.com/products/impact-and-tilt/impact-indicators (http://shockwatch.com/products/impact-and-tilt/impact-indicators)

Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 27, 2017, 05:13:24 pm
Yep, G force numbers look big on paper but a sharp tap can easily produce hundreds of Gs for an instant.

Real engineers carry their meters in huge foam padded cases and only take them out on site.

What would you do if you dropped your meter as you took it out of the case on site? Say 'sorry I can't use that' and come back next day?  :popcorn:

Bring two of them?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 05:23:49 pm
You should not expect people to do something you are not willing to do yourself.  It's fine to ask but don't expect it.

I don't have currently one of those meters on my table with the intention of doing bad things to it later. If I did I wouldn't be against a few more knock tests.

I know you're waiting for Brymen(*) to comment before opening it up, etc. Maybe you can do the bashing after all the electrical testing is over and the back is off. You could attach some wires to the relay and flash a LED when it changes position - it doesn't matter if the meter is dead or alive for that.

Is a test of the of the fancy input-jack-blocking mechanism's robustness also in the agenda? I believe there was interest shown earlier.


Edit: I meant Gossen, of course.
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on May 27, 2017, 06:12:15 pm
I have a recommendation for your next meter to test, the Prova 803 http://www.prova.com.tw/product_detail.asp?seq=49 (http://www.prova.com.tw/product_detail.asp?seq=49) (or the Prova 901/903 which is true RMS and 200 kHz bandwidth)

It just looks so funky.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 06:14:06 pm
I know you're waiting for Brymen...

Gossen

Gossen!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: PA4TIM on May 27, 2017, 06:17:01 pm
The meter survived shipment to my house across the ocean.  I would guess it saw some pretty big changes in temperature, pressure and vibration.


I already gave the example of driving across a farm with the meter loose in the back of a pickup truck. That's real world, it could happen.



In your world maybe, not in mine.  ;)

The worst shock my meters get is when they flip over on the bench in my lab.

My 6 year old Agilent U1252A shows different wear. The blue "foam" is desintegrating. I had to replaced the common bus, the probes fell apart (the foam, became real sticky), The testleads from the black lead broke several times just at the connector. Very strange leads, there is a sort of black stuff around the core, looks like graphite or so. But I use them every day so no complains, I do like them because the resistance is very low and stable. I wonder if the stuff is there to lower the triboelectric effect. HP did something like that for the testleads (i do not have) of the HP4329 ( I do have: http://www.pa4tim.nl/?p=2269 (http://www.pa4tim.nl/?p=2269) ) I replaced the 9V nimh twice and repaired the charger.

Most important for me, it is still spot on.

Safety is probably not as big thing for my job as for others. But I'm glad it is safe. As long as it survives stupid things like probing 350VDC in a smps still in diode or resistance mode I'm happy. I have 2 HV probes and for current I use shunts, clampmeters, current probes and a fluxgate probe.

The big 440mA fuse of my Agilent failed, I have no clue how, maybe when the charger or a battery failed.  I never use it for current. So I rebuild the big 440mA fuse with parts of a panel-fuse holder and dropped a small glass-fuse in it. The only current it sees is from the charger.

After Joes videos I'm thinking about a Brymen 869s as a second handmeter.  I'm not a Fluke fanboy, I could cuff up lot of money I probably bought a Keysight (one with the oled screen).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 06:40:56 pm
You should not expect people to do something you are not willing to do yourself.  It's fine to ask but don't expect it.

I don't have currently one of those meters on my table with the intention of doing bad things to it later. If I did I wouldn't be against a few more knock tests.

I know you're waiting for Brymen(*) to comment before opening it up, etc. Maybe you can do the bashing after all the electrical testing is over and the back is off. You could attach some wires to the relay and flash a LED when it changes position - it doesn't matter if the meter is dead or alive for that.

Is a test of the of the fancy input-jack-blocking mechanism's robustness also in the agenda? I believe there was interest shown earlier.


Edit: I meant Gossen, of course.

You have meters.  Subject them to what your idea of real world is and video tape it.  Then I will have some idea what your real world is.  Don't link me your meter on a rope video.

I am not a fan of that DC input jack.  First it just seems like a stupid idea.  They seal it from the inside but there is no rubber plug to seal it from the outside.  If they do offer it, I bet its $20 for one! 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 06:51:08 pm
The meter survived shipment to my house across the ocean.  I would guess it saw some pretty big changes in temperature, pressure and vibration.


I already gave the example of driving across a farm with the meter loose in the back of a pickup truck. That's real world, it could happen.



In your world maybe, not in mine.  ;)

The worst shock my meters get is when they flip over on the bench in my lab.

...

Safety is probably not as big thing for my job as for others. But I'm glad it is safe. As long as it survives stupid things like probing 350VDC in a smps still in diode or resistance mode I'm happy. I have 2 HV probes and for current I use shunts, clampmeters, current probes and a fluxgate probe.

The big 440mA fuse of my Agilent failed, I have no clue how, maybe when the charger or a battery failed.  I never use it for current. So I rebuild the big 440mA fuse with parts of a panel-fuse holder and dropped a small glass-fuse in it. The only current it sees is from the charger.

After Joes videos I'm thinking about a Brymen 869s as a second handmeter.  I'm not a Fluke fanboy, I could cuff up lot of money I probably bought a Keysight (one with the oled screen).

For the Brymen, that's pretty much the same mechanical shock test mine gets, it falls over on it's side sitting on the bench. 

I would be interested in seeing your fuse mods.  I bought a bag of five the large body HRC fuses from Digikey for not too much. Seems like under $5/ea and they are not counterfeit.       

There are some pretty interesting videos of the OLED meters in direct sunlight.  I see a fair number of posts about them having a short life.   One day I may look into it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 07:51:58 pm
In your world maybe, not in mine.  ;)
Don't you have any curiosity about the physical limits of this meter?

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 08:11:41 pm
The relay they use is a Panasonic DS2E-SL2-DC5V
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 27, 2017, 08:42:13 pm
What makes you think I have not given up on Gossen and that the meter is still together?   Do you really feel that I have not already done bad things to it or that its not damaged beyond repair already?
It's open and the soldering iron's out.  :scared:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=319148)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 09:04:21 pm
Dave's ghost meter is watching the surgery, knowing one day it will be his turn.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: PA4TIM on May 27, 2017, 09:21:26 pm
In your world maybe, not in mine.  ;)
Don't you have any curiosity about the physical limits of this meter?

No, should I ?
I only use it in my lab, I repair measurement and calibration gear for a living. Most used meters here are the Agilent U1252A and a Keithley 2000

Joe: I will make a photo of the fuse (if I do not forget)
I do not use the meter outside, but if I see it on vlogs it looks very well readable in house and that is very important for me. I like the color screen of your uni-T (181 ?  the left one on the picture above)
I want a fast meter, accurate, stable over time and temp. The Brymen seems to do all what I need and want.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 09:33:40 pm
In your world maybe, not in mine.  ;)
Don't you have any curiosity about the physical limits of this meter?
No, should I ?
You're the one posting in this multimeter testing  thread, you tell me...  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 27, 2017, 09:52:43 pm
Don't link me your meter on a rope video.
Says the guy who climbs on the roof of his house to throw meters off it.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 27, 2017, 10:00:40 pm
Don't link me your meter on a rope video.
Says the guy who climbs on the roof of his house to throw meters off it.  :popcorn:
Didn't see any throwing.....just careful release (liberation) into the atmosphere.

That in itself is also valid information to add to the choice of a DMM to buy...........those that can be clipped back together and continue to be used.  :phew:
Title: Re: Handheld meter electrical robustness testing.
Post by: PA4TIM on May 27, 2017, 10:12:53 pm
I'm interested in Joe's tests because it is informative and he has a sound knowledge.  Besides that it is related to my work.

But I think there is a misunderstanding about the meaning of physical limits. I do not care what a meter does if you trow it of the roof, I do care about transients etc because I measure a lot in SMPS's and PAT testers. I just finished a Valhalla calibrator that goes up to 1000V and now there is a G&M secutest on the bench  (and a second one is waiting) They make 500V.

About safety in those secutests: I have seen 2 of them with vaporized inner traces !! and all protection devises still good.Pictures of the repair of that damage: http://schneiderelectronicsrepair.nl/?p=481 (http://schneiderelectronicsrepair.nl/?p=481)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 11:05:55 pm
Don't link me your meter on a rope video.
Says the guy who climbs on the roof of his house to throw meters off it.  :popcorn:
Didn't see any throwing.....just careful release (liberation) into the atmosphere.

That in itself is also valid information to add to the choice of a DMM to buy...........those that can be clipped back together and continue to be used.  :phew:

Since 5KY's UT61E was dropped from the roof, I used it to show:

How much current the meter could handle if you short out the fuse
What happens when you jumper out a fuse with wire
Used it for target practice with my jumped fuse rocket
Test the amount of current seen by the controller IC during an ESD event and how to protect for it
Used the shunt to see how much current it could carry and help design a new shunt
Used it to mock up a low burden voltage circuit

Too much work to make a list...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2017, 11:16:51 pm
Don't link me your meter on a rope video.
Says the guy who climbs on the roof of his house to throw meters off it.  :popcorn:

They were all heading to the recycle bin.   Of course there were dremel repairs, some target practice with the bow, the neon sign transformer and going ice fishing with the UT90A as well.  You can't leave those out.   Your soap on a rope was a perfectly good meter.  Mine were all dead except for the UT90A which is beyond dead, it's a zombie meter!   

Now that you have the part number, you should order up some of those relays and show us a thing or two about mechanical stress testing.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 28, 2017, 09:16:51 am
They were all heading to the recycle bin.  Your soap on a rope was a perfectly good meter.

Yours were all "perfectly good" when they arrived at your house. Damages suffered in-between weren't accidental.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 28, 2017, 09:21:35 am
They were all heading to the recycle bin.  Your soap on a rope was a perfectly good meter.

Yours were all perfectly good when they arrived at your house and damages suffered in-between weren't accidental.
All ?
That's a matter of opinion.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 28, 2017, 11:05:12 am
That's a matter of opinion.
So is joe's assertion that my DT830 was a "perfectly good meter" before I tied a string to it and towed it behind a canoe.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2017, 01:47:05 pm
They were all heading to the recycle bin.  Your soap on a rope was a perfectly good meter.

Yours were all "perfectly good" when they arrived at your house. Damages suffered in-between weren't accidental.

Nothing gets past you!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2017, 02:02:51 pm
That's a matter of opinion.
So is joe's assertion that my DT830 was a "perfectly good meter" before I tied a string to it and towed it behind a canoe.

Based on your in depth functional test, yes.  I was thinking about this part of your video for your relay testing:

https://youtu.be/DWBSBJ16zWg?t=175

You could mount 100pcs to a PCB, set them to one state, then attach your rope and drag the whole thing down the stares.  Measure how many relays changed states once you get the to bottom.    The do the drop test you show and test them again.  Maybe do a checkerboard pattern on the board, 50% of the relays set in the opposite state of the others so you can see what effects that has.   

Some one had asked me about doing a similar test with pots.  Maybe you could mount some to your test board as well. Measure their before and after resistance.   

Again the GMC meter I have that you are interested in uses a Panasonic DS2E-SL2-DC5V.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 28, 2017, 02:23:03 pm
That's a matter of opinion.
So is joe's assertion that my DT830 was a "perfectly good meter" before I tied a string to it and towed it behind a canoe.

Based on your in depth functional test, yes.

By that definition it's still a perfectly good meter!

All I managed to break was the battery and the case. The meter is in a drawer and still powers on and measures.

I'm more interested in a test that would leave your meter looking perfect on the outside but with the relay changed inside. eg. If it's on the stand and topples over onto a hard screwdriver handle.

Again: The point of slapping it around a bit is just to get a feel of what it takes to move the relay inside the meter. It was never meant to be a rigorous or accurate measurement, just a starting point for (possibly) further tests.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2017, 03:00:05 pm
That's a matter of opinion.
So is joe's assertion that my DT830 was a "perfectly good meter" before I tied a string to it and towed it behind a canoe.

Based on your in depth functional test, yes.

By that definition it's still a perfectly good meter!

All I managed to break was the battery and the case. The meter is in a drawer and still powers on and measures.

I'm more interested in a test that would leave your meter looking perfect on the outside but with the relay changed inside. eg. If it's on the stand and topples over onto a hard screwdriver handle.

Again: The point of slapping it around a bit is just to get a feel of what it takes to move the relay inside the meter. It was never meant to be a rigorous or accurate measurement, just a starting point for (possibly) further tests.


Yes, based on your level of testing it was still a perfectly good meter.

I understand your interest and reasons for wanting to see some sort of mechanical tests ran.   I have even gone so far as to provide you with a part number for the relay used so you can run what ever tests you like.   You just need to take that first step and procure some. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on May 28, 2017, 05:37:17 pm
just wanted to say,
dropping a meter off the roof or down some stairs is perfectly valid,
we dont all work from a desk!!

a have had meters go down stairs, drop about a meter onto concrete - several times, had to use them in the rain,  and a few other misshaps too.
droptest should always be done with probes attached btw,
because it often lands on them and can stress the sockets or pcb if your unlucky.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 28, 2017, 06:07:05 pm
One safety standard for electrical equipment (IEC 61010) specifies that a product must survive a one meter drop at both its highest and lowest specified operating temperatures. (quote from a Fluke document)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 28, 2017, 06:32:34 pm
One safety standard for electrical equipment (IEC 61010) specifies that a product must survive a one meter drop at both its highest and lowest specified operating temperatures. (quote from a Fluke document)
Interesting.........I was always under the impression the drop test was for 2 meters, I must have had that wrong.  :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 28, 2017, 06:35:19 pm
Another one:
To measure the drop protection of Klein Tools digital meters and electrical testers, a series of tests are performed in conditions far exceeding the UL/IEC standard. UL/IEC requires a drop of three feet onto a 50 mm thick hardwood board supported by rigid steel or concrete.  By contrast, Klein Tools drop tests from 3 to 9.8 ft. onto a rigid steel surface. The MM500, for example, passed Klein's drop test of over 20 drops from 9.8 ft. without damage to the meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2017, 07:47:53 pm
Part 6 is up

https://www.youtube.com/watch?v=XvpGa8ieit0 (https://www.youtube.com/watch?v=XvpGa8ieit0)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2017, 07:51:06 pm
just wanted to say,
dropping a meter off the roof or down some stairs is perfectly valid,
we dont all work from a desk!!

a have had meters go down stairs, drop about a meter onto concrete - several times, had to use them in the rain,  and a few other misshaps too.
droptest should always be done with probes attached btw,
because it often lands on them and can stress the sockets or pcb if your unlucky.

I don't think anyone would suggest that mechanical testing is not important.  It's just not something that interests me. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2017, 07:56:17 pm
One safety standard for electrical equipment (IEC 61010) specifies that a product must survive a one meter drop at both its highest and lowest specified operating temperatures. (quote from a Fluke document)

The equipment is dropped so that it lands in the position expected to present the most severe condition.

Non-metallic ENCLOSURES of equipment with a minimum RATED ambient temperature below 2 °C are cooled to the minimum RATED ambient temperature, then tested within 10 min.
Title: Re: Handheld meter electrical robustness testing.
Post by: The Soulman on May 28, 2017, 09:46:53 pm
Does it auto-range on the resistance mode that quick or did you cut it out of the video?

Here's what happened: (German accent->on)

Marketing: We need a Bluetooth multi-meter, Bluetooth is really cool..
Engineering: That's silly, who would use that, and think of the all the work involved.
Management: can't we put in some standard module to save a lot of work? Work=money you know.
Engineering: Yes but think of the rf interference caused in this precision device, and to fit the bloody
BT module we must leave out the standard shield, that could cause all sorts of trouble!
Management: Leave out the standard shield you say? Very good! Those are outsourced and cost 43 cents each and 16 seconds of manual assembly time, great!
What a good day it is to be a manager.

(German accent->off)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2017, 12:00:17 am
Does it auto-range on the resistance mode that quick or did you cut it out of the video?

Here's what happened: (German accent->on)

Marketing: We need a Bluetooth multi-meter, Bluetooth is really cool..
Engineering: That's silly, who would use that, and think of the all the work involved.
Management: can't we put in some standard module to save a lot of work? Work=money you know.
Engineering: Yes but think of the rf interference caused in this precision device, and to fit the bloody
BT module we must leave out the standard shield, that could cause all sorts of trouble!
Management: Leave out the standard shield you say? Very good! Those are outsourced and cost 43 cents each and 16 seconds of manual assembly time, great!
What a good day it is to be a manager.

(German accent->off)

If you want to see how fast the meter autoranges, I suggest watching the earlier videos.  My functional testing takes too much time so I edit it down.

A few steps in the process:
Engineer: What about the safety? 
Manager: Do we meet the letter of the law?
Engineer: IEC does not test with high magnetic forces like the $70 hanger we sell with the meter but it can cause the meter to be in an unsafe state.
Manager: Not our problem. We are not the experts writing the specs.  As long as we meet the letter of the law we are good to go.
Safety inspector:  Looks good to me.
Average Customer: Looks good to me.
Spouse of average customer after tragic event:  Sniff..
Spouses attorney: We believe your spouse was not at fault and there may be a design flaw with the meter.  We saw it on YT...

Several months go by:
Manager:  Sorry engineer, we need a scape goat and you are it!  In the mean time, I bought a new yacht with the bonus I got from all the money we saved.   Clean out your drawers by the end of the day.

Several months go by:
Engineer takes the stand and has saved the emails and voice mails documenting the history on their personal cell phone. 

In the mean time, Extech has finished with their recall of their clamp meters being the mid range supplier they are.
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 29, 2017, 01:06:12 am
Does it auto-range on the resistance mode that quick or did you cut it out of the video?

Here's what happened: (German accent->on)

Marketing: We need a Bluetooth multi-meter, Bluetooth is really cool..
Engineering: That's silly, who would use that, and think of the all the work involved.
Management: can't we put in some standard module to save a lot of work? Work=money you know.
Engineering: Yes but think of the rf interference caused in this precision device, and to fit the bloody
BT module we must leave out the standard shield, that could cause all sorts of trouble!
Management: Leave out the standard shield you say? Very good! Those are outsourced and cost 43 cents each and 16 seconds of manual assembly time, great!
What a good day it is to be a manager.

(German accent->off)

If you want to see how fast the meter autoranges, I suggest watching the earlier videos.  My functional testing takes too much time so I edit it down.

A few steps in the process:
Engineer: What about the safety? 
Manager: Do we meet the letter of the law?
Engineer: IEC does not test with high magnetic forces like the $70 hanger we sell with the meter but it can cause the meter to be in an unsafe state.
Manager: Not our problem. We are not the experts writing the specs.  As long as we meet the letter of the law we are good to go.
Safety inspector:  Looks good to me.
Average Customer: Looks good to me.
Spouse of average customer after tragic event:  Sniff..
Spouses attorney: We believe your spouse was not at fault and there may be a design flaw with the meter.  We saw it on YT...

Several months go by:
Manager:  Sorry engineer, we need a scape goat and you are it!  In the mean time, I bought a new yacht with the bonus I got from all the money we saved.   Clean out your drawers by the end of the day.

Several months go by:
Engineer takes the stand and has saved the emails and voice mails documenting the history on their personal cell phone. 

In the mean time, Extech has finished with their recall of their clamp meters being the mid range supplier they are.

100% Correct ! I've seen it first hand, minus the yacht and few specifics.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 29, 2017, 09:16:29 am
$800, 6-digit meter with no internal shielding at all?

 :palm:

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2017, 01:32:57 pm
$800, 6-digit meter with no internal shielding at all?

 :palm:

Here I thought nothing got by you. There is a shield on one side of the board.  If you watch Dave's video of the Xtra, you will see the same 4 PTHs where the second shield mounts to.   That shield does not look like it would have worked for the Ultra BT.   

The questions I have is does the A model (no BT) have a shield on the backside and is my B model missing a shield from the factory or was this by design?   Because Gossen has had no contact with me and Dranetz went so far as to block my email over a simple question of getting the meter aligned, I doubt I will ever know. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 29, 2017, 01:56:50 pm
I've never seen a Gossen meter with a metal shield on the back. Most have a plastic cover secured with one screw to the PCB. (The old models at least)
I checked the one fitted on the 30M. It doesn't seem to be conductive, unless there is perhaps an internal metallic layer.

(https://www.eevblog.com/forum/index.php?action=dlattach;topic=49477.0;attach=156670;image)

https://www.eevblog.com/forum/testgear/adjustment-of-metrahit-18s-and-18c/?action=dlattach;attach=156669;image (https://www.eevblog.com/forum/testgear/adjustment-of-metrahit-18s-and-18c/?action=dlattach;attach=156669;image)

This PRO model has 2 shields, but they might both go in the front of the PCB:

(https://www.eevblog.com/forum/index.php?action=dlattach;topic=79281.0;attach=275277;image)

https://www.eevblog.com/forum/repair/metrahit-pro-leaked-battery-repair-attempt/?action=dlattach;attach=275276;image (https://www.eevblog.com/forum/repair/metrahit-pro-leaked-battery-repair-attempt/?action=dlattach;attach=275276;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 29, 2017, 02:04:07 pm
$800, 6-digit meter with no internal shielding at all?
Here I thought nothing got by you. There is a shield on one side of the board.

I wrote that just after you took the back off, a few minutes into the video. I was expecting full internal shielding on a meter of that class. Front and back, either on the inside of the case or a fitted metal shield like the one you made.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2017, 02:30:47 pm
I've never seen a Gossen meter with a metal shield on the back. Most have a plastic cover secured with one screw to the PCB. (The old models at least)
I checked the one fitted on the 30M. It doesn't seem to be conductive, unless there is perhaps an internal metallic layer.

(https://www.eevblog.com/forum/index.php?action=dlattach;topic=49477.0;attach=156670;image)

https://www.eevblog.com/forum/testgear/adjustment-of-metrahit-18s-and-18c/?action=dlattach;attach=156669;image (https://www.eevblog.com/forum/testgear/adjustment-of-metrahit-18s-and-18c/?action=dlattach;attach=156669;image)

This PRO model has 2 shields, but they might both go in the front of the PCB:

(https://www.eevblog.com/forum/index.php?action=dlattach;topic=79281.0;attach=275277;image)

https://www.eevblog.com/forum/repair/metrahit-pro-leaked-battery-repair-attempt/?action=dlattach;attach=275276;image (https://www.eevblog.com/forum/repair/metrahit-pro-leaked-battery-repair-attempt/?action=dlattach;attach=275276;image)

I'm curious now if there is a shield under that plastic cover in the first picture. 

The second picture looks like the shields shown on Dave's Xtra.  Makes sense they would keep them all the same.  Maybe they felt it was not worth the cost to tool one for the BT model.   

Also it makes me wonder if the Energy is sensitive to static like the Ultra.  They appear to use a different relay.  Maybe it does not have the same sensitivity.   
Title: Re: Handheld meter electrical robustness testing.
Post by: The Soulman on May 29, 2017, 03:04:52 pm

I'm curious now if there is a shield under that plastic cover in the first picture. 

The second picture looks like the shields shown on Dave's Xtra.  Makes sense they would keep them all the same.  Maybe they felt it was not worth the cost to tool one for the BT model.   


My metrahit 2+ appears to have the exact same shield as in the first photo and it hasn't a second shield underneath it, it must be some special plastics.

Always wondered what those randomly placed holes where for, now I know.  :P

Edit: after 1 minute of google I've found this material:
https://www.rtpcompany.com/products/emi-shielding/ (https://www.rtpcompany.com/products/emi-shielding/)
The shield/cover is probably made out of something like that.
Title: Re: Handheld meter electrical robustness testing.
Post by: chronos42 on May 29, 2017, 03:05:30 pm
   

Also it makes me wonder if the Energy is sensitive to static like the Ultra.  They appear to use a different relay.  Maybe it does not have the same sensitivity.   

Hi,

no, my Energy has no Problems with static discharging in all ranges.
It also has only one metal shield on the backside, at the topside is a plugin board with the power measurment processor.
It contains two Relais, not sure if this are the same type or not. (I assume they are different)

I was not able to trigger the relays with a magnet or a degausing coil,  my magnet and the coil seems too weak for this.

But I did check this:

Switch the meter on and then set it from the V mode to resistor mode, one of the relais clicks.
Then I switched off the meter, set in the V mode and turned it on again. The relais was set back to the correct state, it worked as expected. (Firmware rev. is 1.20)

Regards
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 29, 2017, 08:04:26 pm
$800, 6-digit meter with no internal shielding at all?

 :palm:

Here I thought nothing got by you. There is a shield on one side of the board.  If you watch Dave's video of the Xtra, you will see the same 4 PTHs where the second shield mounts to.   That shield does not look like it would have worked for the Ultra BT.   

The questions I have is does the A model (no BT) have a shield on the backside and is my B model missing a shield from the factory or was this by design?   Because Gossen has had no contact with me and Dranetz went so far as to block my email over a simple question of getting the meter aligned, I doubt I will ever know.

My email address is fresh (unblocked), if you like I'll send "them", a single message with a link to this thread. You can PM me with their contact info, up to you, not much to lose at this point if you've somehow been blocked, which is really odd.
Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on May 29, 2017, 10:14:21 pm
I wonder if there might be a drop-in,  ground-shielded version of this relay. It might be possible to retrofit affected models.

Or alternatively, a firmware fix so the relay is at least pulsed at turn-on? This seems doable.

Pardon me if this has been suggested - I've been following the thread but could have missed something.
Title: Re: Handheld meter electrical robustness testing.
Post by: The Soulman on May 29, 2017, 10:23:52 pm
Or construct a alternative blue-tooth module with a large ground plane?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 29, 2017, 11:59:12 pm
Second post about the need for a grounded shield on the relay.   :-//   My concern with the relay is preventing a state change from an outside low frequency magnetic force like I show in the videos.

My email address is fresh (unblocked), if you like I'll send "them", a single message with a link to this thread. You can PM me with their contact info, up to you, not much to lose at this point if you've somehow been blocked, which is really odd.

I did create a playlist if you wanted to link that as well. 

I used the following two addresses: 
http://www.gossenmetrawattusa.com/contact/index.html (http://www.gossenmetrawattusa.com/contact/index.html)

https://www.gossenmetrawatt.com/english/seiten/servicecentersupport.htm (https://www.gossenmetrawatt.com/english/seiten/servicecentersupport.htm)


   

Also it makes me wonder if the Energy is sensitive to static like the Ultra.  They appear to use a different relay.  Maybe it does not have the same sensitivity.   

Hi,

no, my Energy has no Problems with static discharging in all ranges.
It also has only one metal shield on the backside, at the topside is a plugin board with the power measurment processor.
It contains two Relais, not sure if this are the same type or not. (I assume they are different)

I was not able to trigger the relays with a magnet or a degausing coil,  my magnet and the coil seems too weak for this.

But I did check this:

Switch the meter on and then set it from the V mode to resistor mode, one of the relais clicks.
Then I switched off the meter, set in the V mode and turned it on again. The relais was set back to the correct state, it worked as expected. (Firmware rev. is 1.20)

Regards

Thanks for checking.  The Ultra can also detect the rotary switch change and cycle the relay if it was done during a power down.  This meter is using 1.23.  No idea if they use the same firmware for all the Metrahit meters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 30, 2017, 12:01:45 am
Second post about the need for a grounded shield on the relay.   :-//   

Apparently some people think a grounded shield will block magnetic fields...  :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 30, 2017, 01:32:56 am
Dave's ghost meter is watching the surgery, knowing one day it will be his turn.   :-DD
And that day is getting closer.  :)

https://youtu.be/h4kxdhxDcq0
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 30, 2017, 01:51:04 am
I like the case.  It looks sharp with the zipper.  Lots of detail.  Of course, in the end, all that fluff won't help it survive the grill starter.  Looking forward to seeing just how robust this little beast is compared with all the other meters I have looked at. 
Title: Re: Handheld meter electrical robustness testing.
Post by: sleemanj on May 30, 2017, 01:52:44 am
Apparently some people think a grounded shield will block magnetic fields...  :palm:

Well to be fair it's an easy error in thought to make.

To those playing along, the type of metal surrounding the relay is what is important for the magnetic concern, not where it's connected to.  Mu-Metal, as joeqsmith used in his can is what's needed - https://en.wikipedia.org/wiki/Mu-metal#Magnetic_shielding

Magnetically shielded relays (essentially, relays with a mu-metal shield pre-fitted over the top) are available.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 30, 2017, 03:24:57 am
I like the case.  It looks sharp with the zipper.  Lots of detail.  Of course, in the end, all that fluff won't help it survive the grill starter.  Looking forward to seeing just how robust this little beast is compared with all the other meters I have looked at.

Would that be your famous  "pee-zee-oh" grill starter?   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 30, 2017, 05:35:53 am
Protected yourself and your pacemaker from evil magnetic holders:
$65.95 only!
50% reduction of AC and DC magnetic fields!
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 30, 2017, 05:42:41 am
Protected yourself and your pacemaker from evil magnetic holders:
$65.95 only!
50% reduction of AC and DC magnetic fields!





:-DD
:-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on May 30, 2017, 06:43:50 am
Everything I have ever seen about Gossen just makes me think "Overpriced bullshit". These videos have not done anything to sway me from this at all.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 30, 2017, 06:48:50 am
Everything I have ever seen about Gossen just makes me think "Overpriced bullshit". These videos have not done anything to sway me from this at all.

you have seen the wrong things and been misinformed by the whitch hunters...
Title: Re: Handheld meter electrical robustness testing.
Post by: The Soulman on May 30, 2017, 08:38:45 am
Second post about the need for a grounded shield on the relay.   :-//   

Apparently some people think a grounded shield will block magnetic fields...  :palm:

No, but it will help to reduce the "theremin" effect.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 30, 2017, 09:46:08 am
Everything I have ever seen about Gossen just makes me think "Overpriced bullshit". These videos have not done anything to sway me from this at all.

you have seen the wrong things and been misinformed by the whitch hunters...

What bullshit ?
Who in their right mind would use a two coil relay and NOT ensure is was set to a defined state at power-up.  : :palm:
What about the shielding ?
It is what it is. Do you think Joe made it up ? |O

Gossen have messed up END OF STORY.

Their lack of response to Joe's communication is also arrogant and  RUDE.

Don't be such a fan boy !!

3DB

Title: Re: Handheld meter electrical robustness testing.
Post by: lem_ix on May 30, 2017, 10:43:24 am
Thanks for the videos Joe :-+ As for Gossen, they've lost all credibility with this as far as I'm concerned. At that price point I expect the meter to be beyond rock solid.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 30, 2017, 11:34:18 am
Second post about the need for a grounded shield on the relay.   :-//   

Apparently some people think a grounded shield will block magnetic fields...  :palm:

No, but it will help to reduce the "theremin" effect.

Not around the relay it won't.  The proximity effect was diminished with just the aluminum foil wrapped around the outside case.  The shield serves more than one purpose. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 30, 2017, 11:44:43 am
These are high count very specialized CAT III 600V only meters, with detailed calibration certificates.
Can they be made safer? Possibly, like most other meters. They do come though, with independent testing and meet current regulations.
There is always a premium on price when products are made in Europe and this one also comes with a meaningful 3-year warranty.
As for neodymium susceptibility, it is not very difficult to keep magnets at a safe distance and forego the use of magnetic holders.
It is a small price to pay, as nobody else yet makes a true 300,000 or 1,200,000 count portable meter and may never do.
So, enjoy them while you can, before they disappear completely, under pressure from Asian products.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 30, 2017, 11:58:42 am
These are high count very specialized CAT III 600V only meters, with detailed calibration certificates.
Can they be made safer? Possibly, like most other meters. They do come though, with independent testing and meet current regulations.
There is always a premium on price when products are made in Europe and this one also comes with a meaningful 3-year warranty.
As for neodymium susceptibility, it is not very difficult to keep magnets at a safe distance and forego the use of magnetic holders.
It is a small price to pay, as nobody else yet makes a true 300,000 or 1,200,000 count portable meter and may never do.
So, enjoy them while you can, before they disappear completely, under pressure from Asian products.

I'm enjoying it all right.  Next part, we will see just how robust that front end is.   

I doubt the average person would take the time to see if a magnetic strap would effect their new high count, very specialized CAT III 600V only meters, with detailed calibration certificates.   I personally would have never thought they would release such a product. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 30, 2017, 12:06:26 pm
Everything I have ever seen about Gossen just makes me think "Overpriced bullshit". These videos have not done anything to sway me from this at all.

It may be interesting to look at one of their low end meters.   Personally, for a low count meter with some basic features, I still like Dave's rebranded Brymen.  Seems well made and certainly held up to my testing.

Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on May 30, 2017, 12:14:15 pm
ignore the troll with the "pee-zee-o"... that's what Gossen support said in regard to your emails to them...       :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on May 30, 2017, 02:25:47 pm
These are high count very specialized CAT III 600V only meters, with detailed calibration certificates.
Can they be made safer? Possibly, like most other meters. They do come though, with independent testing and meet current regulations.
There is always a premium on price when products are made in Europe and this one also comes with a meaningful 3-year warranty.
As for neodymium susceptibility, it is not very difficult to keep magnets at a safe distance and forego the use of magnetic holders.
It is a small price to pay, as nobody else yet makes a true 300,000 or 1,200,000 count portable meter and may never do.
So, enjoy them while you can, before they disappear completely, under pressure from Asian products.

I'm enjoying it all right.  Next part, we will see just how robust that front end is.   

I doubt the average person would take the time to see if a magnetic strap would effect their new high count, very specialized CAT III 600V only meters, with detailed calibration certificates.   I personally would have never thought they would release such a product.

You're such a drama queen. So concerned with minute safety aspects. This from someone who rides motorcycles, probably without a helmet too. These meters have been around for at least 20 years, how many people were actually hurt by their Gossen magnetic hanger?
if you're so concerned with magnet safety, there is nothing preventing you from contacting the IEC to ask them to change their recommendations.
I guess that you have to find anything contentious with the expensive meters on test, to keep your audience amused, even at times openly disparaging a review made by the owner of this site. By the way, why is his face on the first frame of one of your videos? Riding coattails?
Any electrician worth his salt would know that relays can be affected by strong magnets and Gossen warns about such eventuality.
All I know is that I'm not about to throw my 30M in the garbage on the strength of your 'review'.  ::)
Have fun with the Ultra, but like the Energy, who doesn't know what the conclusion will be already?
As for the price, the Chauvin Arnoux MTX3293, also made in Europe, costs the same as the Gossen and you only get 100,000 count.

http://www.iec.ch/about/contactus/ (http://www.iec.ch/about/contactus/)
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 30, 2017, 03:57:53 pm
ignore the troll with the "pee-zee-o"... that's what Gossen support said in regard to your emails to them...       :-DD

That's not what they publish on their website.
https://www.gossenmetrawatt.com/english/seiten/aboutus.htm (https://www.gossenmetrawatt.com/english/seiten/aboutus.htm)

Our Most Important Corporate Goals


Economic success
Long-term assurance of the marketability of our products
Satisfied customers
An intact environment

Our Quality Policy

Fulfilling our customers’ requirements is a duty for us.
We design our products and processes in an environmentaly sound fashion.
Legal and official requirements are complied with and checked on a regular basis.
We demand quality and environmental awareness, as well as reliability, from our suppliers too.

Through conscientious performance of his or her job,
each employee fulfils the goal of satisfying his or her customers.

By continuously improving our processes, we intend to constantly enhance the effectiveness of our IM system.
Error prevention comes before error correction.

So in order to implement company policy lets block email from a customer and not respond to questions.  :palm:

3DB


Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on May 30, 2017, 04:08:34 pm
Yea ... typical corporate mission statement(s). Anyone can make 'em -

http://www.jonhaworth.com/toys/mission-statement-generator (http://www.jonhaworth.com/toys/mission-statement-generator)

http://cmorse.org/missiongen/ (http://cmorse.org/missiongen/)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 30, 2017, 04:45:38 pm
That's not what they publish on their website.

That's what *everybody* says on their web site, even Batteroo.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 30, 2017, 05:06:29 pm
These are high count very specialized CAT III 600V only meters, with detailed calibration certificates.
Can they be made safer? Possibly, like most other meters. They do come though, with independent testing and meet current regulations.
There is always a premium on price when products are made in Europe and this one also comes with a meaningful 3-year warranty.
As for neodymium susceptibility, it is not very difficult to keep magnets at a safe distance and forego the use of magnetic holders.
It is a small price to pay, as nobody else yet makes a true 300,000 or 1,200,000 count portable meter and may never do.
So, enjoy them while you can, before they disappear completely, under pressure from Asian products.

I'm enjoying it all right.  Next part, we will see just how robust that front end is.   

I doubt the average person would take the time to see if a magnetic strap would effect their new high count, very specialized CAT III 600V only meters, with detailed calibration certificates.   I personally would have never thought they would release such a product.

You're such a drama queen. So concerned with minute safety aspects. This from someone who rides motorcycles, probably without a helmet too. These meters have been around for at least 20 years, how many people were actually hurt by their Gossen magnetic hanger?
if you're so concerned with magnet safety, there is nothing preventing you from contacting the IEC to ask them to change their recommendations.
I guess that you have to find anything contentious with the expensive meters on test, to keep your audience amused, even at times openly disparaging a review made by the owner of this site. By the way, why is his face on the first frame of one of your videos? Riding coattails?
Any electrician worth his salt would know that relays can be affected by strong magnets and Gossen warns about such eventuality.
All I know is that I'm not about to throw my 30M in the garbage on the strength of your 'review'.  ::)
Have fun with the Ultra, but like the Energy, who doesn't know what the conclusion will be already?
As for the price, the Chauvin Arnoux MTX3293, also made in Europe, costs the same as the Gossen and you only get 100,000 count.

http://www.iec.ch/about/contactus/ (http://www.iec.ch/about/contactus/)

Strange you would bring up helmets and assume I would not use one.  But because you brought it up, we are required to wear a helmet that is in current cert and a shield along with other requirements.

I doubt the Metrahit Ultra M248B has been in production 20 years. 

You know, I don't know why YT picked Dave's face for the icon.  I normally leave these at what ever defaults they come up with.  I assume they have some algorithms that make the selection.

In a way, I would say I am riding Dave's coattail. Had he not reviewed the couple of Gossens I doubt I would be looking at one now.   But my reviews are always going to dig into more details and I am always going to be checking for their failure point.  It's been like that for some time and not something new to this Gossen.  I find it interesting how my views of this particular meter are in such a contrast with Dave's, which is why I added  some snips.  I will say that it has taken me longer to review it because it has had so many problems that I normally don't see.   Certainly not something I would have anticipated with the price of the meter. 

I have not ran the Gossen yet and can't predict the results.  I've seen meters I thought would fail really low do very good.  Other I would think would survive well have done poorly. 
Title: Re: Handheld meter electrical robustness testing.
Post by: OldNeurons on May 30, 2017, 08:15:11 pm
For your information, here is an e-mail that I sent to GMC some days ago, and the reply, from GMC Germany I assume, and  forwarded by GMC France.

My E-mail:

=========================================================================
De : ..................................................
Envoyé : mercredi 24 mai 2017 22:33
À : GMC-I Service GmbH; FR, Info
Objet : Metrahit Ultra M248B issue

Dear Madam, dear Sir,

I was close to buy one of the model mentioned in the subject, and, when looking at some reviews on the web, I found this:

https://www.youtube.com/watch?v=9LjWtdgJhkg (https://www.youtube.com/watch?v=9LjWtdgJhkg)
https://www.youtube.com/watch?v=wYuzFtoHMqg (https://www.youtube.com/watch?v=wYuzFtoHMqg)
https://www.youtube.com/watch?v=sZChenxYv04 (https://www.youtube.com/watch?v=sZChenxYv04)
https://www.youtube.com/watch?v=yD-q6bq7mlE (https://www.youtube.com/watch?v=yD-q6bq7mlE)
https://www.youtube.com/watch?v=YPzbjxNB-fc (https://www.youtube.com/watch?v=YPzbjxNB-fc)
https://www.youtube.com/watch?v=u0AOIQxXKh4 (https://www.youtube.com/watch?v=u0AOIQxXKh4)
https://www.youtube.com/watch?v=COuCsWDoI9E (https://www.youtube.com/watch?v=COuCsWDoI9E)
...

No need to say that I have postponed my purchase.

According the author of these videos, he wrote a letter to your company, but did not receive yet any reply.

I doubt that this is an isolated issue affecting only that unit.

Before I take any decision, I would like to know:

1) If this is an isolated problem.
2) What are the models in your products list which are affected by these issues.
3) Do you intend to solve these issues ?

Regards.

=========================================================================




GMC Germany reply, forwarded by GMC France:

=========================================================================
Bonjour monsieur ..........,

Au nom de l’équipe GMC Instruments, je vous remercie pour l’attention que vous portez à nos produits.

Vous trouverez ci-dessous la réponse que le responsable de l’activité multimètres a donné à vos questions. J’espère qu’elles répondront à vos attentes. Si tel n’est pas le cas, n’hésitez pas à nous demander toute précision que vous jugerez nécessaires.

Bien cordialement,

Bruno COMBY
Managing Director

GMC Instruments France SAS

 

No need to say that I have postponed my purchase.

We regret that you postpone your purchase, because METRAHIT ULTRA is a robust precision multimeter despite the behavior reported by Smith in the EEVBLOG. 

 

According the author of these videos, he wrote a letter to your company, but did not receive yet any reply.

Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter. 

I doubt that this is an isolated issue affecting only that unit.

Before I take any decision, I would like to know:

1)      If this is an isolated problem.

It is true, we recognized a sensitivity of the METRAHIT ULTRA to electromagnetic interferences (susceptibility) too. This can be recognized for strong electric fields. Joe Smith tested with 10V/m, a relatively high field strength leading to the observations he made. We usually test with 3V/m which does not affect the METRAHIT ULTRA. Please observe that the device is nevertheless compliant to all relevant ISO standards. Furthermore this can be observed only in the lowest DC measuring range, the 300 mV range we has to be selected manually, i.e. not in AUTO range mode. 

Nevertheless we started in our R&D a process to improve the immunity of the METRAHIT ULTRA against electrical fields.

We cannot reproduce the observed emission problem at 1.2 GHz. The peak reported in the video is approx.. -90dBm equal to 1pW. We could not find this peak. I might be a resonance problem due to the size of Joe’s cake box. A low level emission below the sensitivity of our test instruments could become larger because of resonance effects in the cake box.      

2)      What are the models in your products list which are affected by these issues.

The other multimeters in our portfolio do not show the same sensitivity as the METRAHIT ULTRA. The problem is solely a subject of METRAHIT ULTRA.

3) Do you intend to solve these issues ?

Yes, we already started activities to improve the EMC of the METRAHIT ULTRA.


Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 30, 2017, 08:25:43 pm
WOW.  :-//
Gossen are watching closely and won't/can't trouble themselves to offer Joe a reply.  :popcorn:

Time to pull the pulser out and see really what this meter can handle.  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on May 30, 2017, 08:38:03 pm
So basically, while Joe is right, meter is EMC sensitive more than we would like to admit (so we started process to improve it) we are royally pissed at Joe that he published this information to the public... And we don't speak to anybody that we don't like , even if the bought a 850 USD meter from us..... How dare he...

LOL
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on May 30, 2017, 08:50:47 pm
If I'm reading this correctly, they didn't like the fact that he simply asked for calibration information and then blacklisted him after that ?
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 30, 2017, 09:04:40 pm
So basically, while Joe is right, meter is EMC sensitive more than we would like to admit (so we started process to improve it) we are royally pissed at Joe that he published this information to the public... And we don't speak to anybody that we don't like , even if the bought a 850 USD meter form us..... How dare he...

LOL
:)
They clearly identified Joe as some motorcycle racing upstart , probably with zero letters behind his name  ::) and not worthy of wasting ink on.  :-DD
One can only hope they see the error of their ways and join up and jump in soon with something concrete about improving their Ultra...........free shields maybe ?

Joe, which other manufacturers have never bothered to offer a reply to your comms ?
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 30, 2017, 09:13:00 pm
Thanks "OldNeurons", for saving me the time, that was a good message you sent. Corporations these days are usually a lot more aware of their online presence, and how important customer feedback and reviews can effect their bottom line. Funny their stating disappointment with you "delaying" your purchase, then at the end admitting there will be a V2.

Be nice if they offered an update for all those with a V1. If it's not a safety issue, then I assume not, but the issue of safety has been brought up, in regards to what mode the meter may or may not be in depending on the state it was last in, set by the relay. Unless that condition just means an inaccurate reading, in which safety could be argued, perhaps?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 30, 2017, 09:35:00 pm
Quote
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter.

Ouch! Whoever wrote that is going to get a roasting when the boss finds out.  :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 30, 2017, 09:52:46 pm
Quote
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter.

Ouch! Whoever wrote that is going to get a roasting when the boss finds out.  :-DD

"Roasting", they are probably tied up right now, getting the GRILL starter treatment!  :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on May 30, 2017, 09:54:44 pm
That's not what they publish on their website.

That's what *everybody* says on their web site, even Batteroo.

Actually it's not.
I didn't see it on the Fluke corporate site.
There again I've noticed that you don't really read posts fully.

3DB
P.S.  Loved your meter review   :-DD :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: OldNeurons on May 30, 2017, 10:00:46 pm
Quote
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter.

Ouch! Whoever wrote that is going to get a roasting when the boss finds out.  :-DD

If you red the reply carefully, you observed that the reply of GMC Germany was forwarded to me by the Managing Director of GMC France.
Personnaly, I was surprised to receive a so quick and frank reply, and would like to thanks GMC for that. It's not common these days ...

I also appreciate Joe's work, and I will let him to give us more details about his discussions with GMC USA.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on May 31, 2017, 05:56:54 am
It'll be interesting to see how this plays out with GMC. By point of comparison, when the Keysight U1270 series was demonstrated to have an EMI issue that affected displayed measurements, they offered to replace the problem DMM with either a corrected version of the same model or the next higher model (U1280 series), even if the affected meter was out of warranty.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on May 31, 2017, 06:21:10 am
Likewise, I almost purchased one of their 30M meters recently which was discussed elsewhere on the forum, I was familiar with the product but not comfortable with the pricing of the additional accessories such as the communications interface, in the end I passed on it, no big deal.

A different enigma altogether, I'm also keen to find out what happened to that Testo video which showed where their multimeters were prone to magnetic fields and in particular the supplied hanging strap, the video has been removed along with the comments, sorry I can't link from this device but it was discussed in mailbag #986 from memory.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 31, 2017, 08:47:38 am
Whoever wrote that is going to get a roasting when the boss finds out.

If you red the reply carefully, you observed that the reply of GMC Germany was forwarded to me by the Managing Director of GMC France.

Internal power struggle at GMC?  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: The Soulman on May 31, 2017, 12:42:02 pm

I'm curious now if there is a shield under that plastic cover in the first picture. 

The second picture looks like the shields shown on Dave's Xtra.  Makes sense they would keep them all the same.  Maybe they felt it was not worth the cost to tool one for the BT model.   


My metrahit 2+ appears to have the exact same shield as in the first photo and it hasn't a second shield underneath it, it must be some special plastics.

Always wondered what those randomly placed holes where for, now I know.  :P

Edit: after 1 minute of google I've found this material:
https://www.rtpcompany.com/products/emi-shielding/ (https://www.rtpcompany.com/products/emi-shielding/)
The shield/cover is probably made out of something like that.

Attached are Photo's of the cover/shield from my metrahit 2+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 01, 2017, 12:45:52 am
Quote
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter.

Ouch! Whoever wrote that is going to get a roasting when the boss finds out.  :-DD

If you red the reply carefully, you observed that the reply of GMC Germany was forwarded to me by the Managing Director of GMC France.
Personnaly, I was surprised to receive a so quick and frank reply, and would like to thanks GMC for that. It's not common these days ...

I also appreciate Joe's work, and I will let him to give us more details about his discussions with GMC USA.


I am not sure what details you are looking for.  I basically read the email chain out loud.   

Gossen did write.  They basically sent the same letter you posted minus this:

Quote
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter. 


I have no idea if anyone at Gossen was provided with the original email chain or if they came to this conclusion on their own or were told this by the rep.  To me, that's not as important as they actually propagated this story to another potential customer without verifying their information. 

Quote
Thanks for the fast response.  I don't think calibration would be a problem.  To be clear I am looking for companies that have the tools required to align the products without the need to ship it back to the factory.  As I understand it, Gossen will sell these tools and I assume there are labs in the US that have invested in them. 

The last one I sent before they blocked:
Quote
I am not asking anyone to share tools, I am asking for a company in the US that can perform an alignment. 
 

My next attempt to go through another source that was bounced back to the original person who blocked:
Quote
I am trying to determine if Gossen has anyone in the US that can perform an alignment of their handheld meters if they no longer pass calibration or do they need to be returned to Germany for alignment?

Their email responses were cherry picked from the information that had been provided.  They make sure to talk about 10V/m and cookie cans but completely ignore the fact that you can't put your hand next to the meter or that something as simple as a magnetic strap can cause the relay to change states and they don't detect it, resulting in the meter displaying very low voltage levels in the AC mode.   

I received a second email from their service department.  This was actually very helpful and included detailed information regarding the commands used to communicate with the meter.  There was nothing proprietary that I could see in the document and I'm not sure why they just don't make it public.  They asked that I contact the US rep if I had further questions.   You can be certain that will not happen any time soon. 

I responded to the original email asking how they concluded I was trying to calibrate the meter myself.  I also asked technical questions concerning how the meter behaves (mentioned earlier).  I provided them with the link to the YT Playlist I created for this meter and offered to provide them with the original email chain if they had not actually received it.   

As of yet I have not heard back from them. 

My plan is to start running the transient tests in the next few days.  Again, this may permanently damage the meter beyond hope of repair.  So if there is anything people want to know feel free to ask now.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 01, 2017, 12:55:45 am
So basically, while Joe is right, meter is EMC sensitive more than we would like to admit (so we started process to improve it) we are royally pissed at Joe that he published this information to the public... And we don't speak to anybody that we don't like , even if the bought a 850 USD meter form us..... How dare he...

LOL
:)
They clearly identified Joe as some motorcycle racing upstart , probably with zero letters behind his name  ::) and not worthy of wasting ink on.  :-DD
One can only hope they see the error of their ways and join up and jump in soon with something concrete about improving their Ultra...........free shields maybe ?

Joe, which other manufacturers have never bothered to offer a reply to your comms ?

To be honest, I really have only written the companies that I perceived as offering higher quality products.  I have written BK, Fluke, Klein Tools, HIOKI, Extech (as well as Ruby),  TPI, Brymen and of course GMC.   Of these only HIOKI never responded.  Too bad really as I have used their products and they really off some great products.  Expensive, but great!  Worth the price!

Brymen has had the most open communications of all the companies.  Actually, Extech and BK have also been very helpful in answering technical questions.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 01, 2017, 12:59:12 am
Quote
Yes, Joe Smith wrote a letter to the subsidiary in the USA. He targeted to receive a description of the interface protocol in order to calibrate the device by himself, which the subsidiary refused to release. This leaded to contrary positions and a not answering to his letter.

Ouch! Whoever wrote that is going to get a roasting when the boss finds out.  :-DD

"Roasting", they are probably tied up right now, getting the GRILL starter treatment!  :-DMM

Again, I am not sure how they came up with that little story.  Maybe the rep was asked and this was what was told.   Don't know, don't care.  It's an internal problem with the company and I am very surprised they would make a statement like this to another customer. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 01, 2017, 01:04:42 am
I'm also keen to find out what happened to that Testo video which showed where their multimeters were prone to magnetic fields and in particular the supplied hanging strap, the video has been removed along with the comments, sorry I can't link from this device but it was discussed in mailbag #986 from memory.

Wonder if they latched like the Ultra.   I'm interested if you ever find the video that shows the problem.
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on June 01, 2017, 01:19:00 am
It's almost a wonder that these test equipment manufacturers don't make special tamper proof screws for their equipment like Apple does (except for the battery and fuse compartments of course). You know if you've ever fixed one like I have they have those teensie pentalobe screws. Of course it all gets defeated, but still it's amazing they don't try to block the "normal" users from getting inside, and only give the entry tools to certified repair or cal centers.

But, I'm glad they don't do it.  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on June 01, 2017, 01:53:59 am
"normal" users of this stuff are engineers - we laugh at security screws.
and they know it!  >:D

they could slap warranty seals over the screw holes or backfill them with epoxy though!!
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on June 01, 2017, 02:03:03 am
"normal" users of this stuff are engineers - we laugh at security screws.
and they know it!  >:D

they could slap warranty seals over the screw holes or backfill them with epoxy though!!
Since when did a foreign screw stop you ?
Grind up a tip.  :)

Had a triangular one the other day that I've never seen, triwing wouldn't fit so ground a spare square one to suit.  :phew:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 01, 2017, 02:40:04 am
I believe that this is what happened with the Extech I own.  I really believe someone owned it before me and had it and the RF link apart.  I would welcome seeing meters with some sort of tamper proof tag so at least sellers would be aware if a customer had it apart.   

It would have no impact on me.  They would still come apart but I have yet to try and return one.   Even when Brymen offered to repair the BM869s after they knew I had damaged it and how, I did not take them up on it.  It's not their fault I run these meter to failure.     
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on June 01, 2017, 03:19:31 am
Even when Brymen offered to repair the BM869s after they knew I had damaged it and how, I did not take them up on it.  It's not their fault I run these meter to failure.   

It is possible perhaps, that they might have liked to inspect the damage to see if they could improve the design? Sending you a good meter in exchange for the broken one seems like a fair trade to get back the damaged meter for examination (which I imagine is the most likely way they would "repair" it.)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 01, 2017, 09:53:42 am
"normal" users of this stuff are engineers - we laugh at security screws.

And we point it out in public, too. It's a negative overall effect, methinks. Joe Public has no interest in opening things up anyway.

Another thing would be tamper-evident screws, or some other way of knowing if it's been taken apart that isn't a stupid shiny sticker. The engineers wouldn't care and the companies would think it voids their warranties so they wouldn't mess around. Overall it improves the brand image.

(nb. I assume the company doesn't go all "warranty void if opened" on their customers, which would be stupid of them).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 01, 2017, 11:43:57 am
Even when Brymen offered to repair the BM869s after they knew I had damaged it and how, I did not take them up on it.  It's not their fault I run these meter to failure.   

It is possible perhaps, that they might have liked to inspect the damage to see if they could improve the design? Sending you a good meter in exchange for the broken one seems like a fair trade to get back the damaged meter for examination (which I imagine is the most likely way they would "repair" it.)

Possible but they had told me what parts they believed had failed based on the tests.  And don't forget they had some ideas about what level the meter was going to fail at.  I also told them what parts were actually damaged.  Just a very open dialog. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 02, 2017, 03:22:24 am
I'm sorry to say, still no response from Gossen to my return emails.  If OldNeuron had not written them, I doubt we would have had any response from them.   

On the plus side, I'm in the final phase of testing.  Early on, I pointed out a note about not exceeding 5 volt with the frequency mode selected.  Of  course, I have already far exceeded that with the ESD and my rectified AC test.  The meter was not damaged.   I don't think I have seen a meter where they have a spec this low.   Time will tell if this is going to be the meter's weakest circuit.   Again, the manual claims it can handle a 1.2 ms rise time! The generator I designed and built comes no where near that.    :-DD :-DD  What could go wrong?? 
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on June 02, 2017, 05:10:16 am
I don't know why anybody would want to exceed 5V on a high frequency logic level (square wave) function. As per the manual, the range is protected up to 600V for 10s.
The meter can measure high voltage line frequency on other selections, without restrictions.

1.2ms is a typo of course. IEC61010 requirement is for 1.2us rise time.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 02, 2017, 10:37:25 am
I don't know why anybody would want to exceed 5V on a high frequency logic level (square wave) function. As per the manual, the range is protected up to 600V for 10s.
The meter can measure high voltage line frequency on other selections, without restrictions.

What I use the meter for is irrelevant.

Again, per your comment above what the meter is used for is irrelevant.   Personally, I see this frequency mode as a gimmick at best.  Old logic may have ran in the sub MHz back in the day of 4000 series CMOS.  If someone were using this technology today (maybe for improve immunity) and running it off of higher than 5V, the meter will not support it.  The thresholds for this mode are also not very forgiving.  I am not really sure what the was the point of them even adding this mode. 

It may not even be that someone wanted to make a frequency measurement.  The person may have just been a mistake.  But again to your point, its all irrelevant.

1.2ms is a typo of course. IEC61010 requirement is for 1.2us rise time.
Yes I pointed out that out during the first video, along with them calling out accessories that are not available to be purchased.  The manual has a few areas that could use some help.  20 years you say?  You would think by now they could correct some of these problems and polish is up a bit.    I would say it's on par with other manuals from mid range meters.     
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on June 02, 2017, 02:10:28 pm
I don't know why anybody would want to exceed 5V on a high frequency logic level (square wave) function.

yes,
i would want it to function upto 24v or maybe even 48v
because i have used it to check sensors in cars.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on June 02, 2017, 02:15:24 pm
You are disingenuous at best.
The Brymen 869 user manual is child-like compared to the information given in the Gossen technical reference.
When I say 20 years, I was referring to the older series, like the 30M for instance, which also has relays susceptible to strong magnets. I can't find any lawsuit seeking damages from Gossen. Can you?
Typos are everywhere, Fluke, Keysight, etc. Nothing to see here.
Quoting somebody out of context usually shows a lack of a convincing argument.
You're blowing smoke again. Most logic voltage level is still at 5V and lower. Most will find the Gossen range very useful.
Besides, no meter does everything. Get something else if it doesn't suit your specialized field.
Looking forward to the rest of the impartial review!
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on June 02, 2017, 02:34:04 pm
You are disingenuous at best.
The Brymen 869 user manual is child-like compared to the information given in the Gossen technical reference.
When I say 20 years, I was referring to the older series, like the 30M for instance, which also has relays susceptible to strong magnets. I can't find any lawsuit seeking damages from Gossen. Can you?
Typos are everywhere, Fluke, Keysight, etc. Nothing to see here.
Quoting somebody out of context usually shows a lack of a convincing argument.
You're blowing smoke again. Most logic voltage level is still at 5V and lower. Most will find the Gossen range very useful.
Besides, no meter does everything. Get something else if it doesn't suit your specialized field.
Looking forward to the rest of the impartial review!

he's been inhaling too much of that magic smoke released during the zapping of the multimeters in his Frankenstein experiments...
:-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on June 02, 2017, 02:45:30 pm
I don't know why anybody would want to exceed 5V on a high frequency logic level (square wave) function.

yes,
i would want it to function upto 24v or maybe even 48v
because i have used it to check sensors in cars.

Are you seriously going to use an 800 quid 300,000 count meter to test sensors on your Bedford truck?
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on June 02, 2017, 02:51:16 pm
you would be surprised what some company's will pay for.
even if it is stupid.
management arent the brightest staff on the payroll.
Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on June 02, 2017, 02:53:42 pm
you would be surprised what some company's will pay for.
even if it is stupid.
management arent the brightest staff on the payroll.

get them to buy a snap-on vantage pro. that's what I got for automotive work.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on June 02, 2017, 07:41:35 pm
The fan boys simply never give up  : :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on June 04, 2017, 12:58:41 pm
The fan boys simply never give up  : :palm:
We know that Joe loves his Brymen 869, but that's no excuse to pin labels on people. Kristallnacht is in the past.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 04, 2017, 08:41:45 pm
Part 7

https://www.youtube.com/watch?v=DFCH9MRGIcA (https://www.youtube.com/watch?v=DFCH9MRGIcA)

A special drop test for Fungus

https://www.youtube.com/watch?v=hE8cJuza_2Q (https://www.youtube.com/watch?v=hE8cJuza_2Q)
Title: Re: Handheld meter electrical robustness testing.
Post by: imidis on June 04, 2017, 10:27:24 pm
Thanks Joe! Awesome work, amazing the problems with a meter in that price range. You don't always get what you pay for.   :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on June 05, 2017, 01:37:37 am
Looks like it survived well but the issues with it are a bit disconcerting for a meter of this price range. The, still, lack of adequate communication from the company back to the original purchaser is very much a Red flag for me though, personally.
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on June 05, 2017, 08:23:56 am
The fan boys simply never give up  : :palm:
We know that Joe loves his Brymen 869, but that's no excuse to pin labels on people. Kristallnacht is in the past.

What the fuck are you on about ?
Why can't you just accept the valid issues with this meter ?
Just because a company has a great reputation does NOT mean that they can't things wrong.
Gossen have already said they are going to sort it out.  :palm:

GET OVER IT !!

3DB


Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on June 05, 2017, 08:38:55 am
:palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on June 05, 2017, 08:40:11 am
:palm:

 :palm: :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 05, 2017, 11:27:57 am
You are disingenuous at best.
The Brymen 869 user manual is child-like compared to the information given in the Gossen technical reference.
When I say 20 years, I was referring to the older series, like the 30M for instance, which also has relays susceptible to strong magnets. I can't find any lawsuit seeking damages from Gossen. Can you?
Typos are everywhere, Fluke, Keysight, etc. Nothing to see here.
Quoting somebody out of context usually shows a lack of a convincing argument.
You're blowing smoke again. Most logic voltage level is still at 5V and lower. Most will find the Gossen range very useful.
Besides, no meter does everything. Get something else if it doesn't suit your specialized field.
Looking forward to the rest of the impartial review!

I'm not aware of a technical reference manual from Gossen.  I have what appears to be a quick start guide and the basic manual for it.   

I would have no way of knowing if the obsolete 30M's internal relays can latch into a wrong state and go undetected, or if it does, could cause the meter to read low AC voltage levels in the presence of high voltage. 

No, I have not looked for lawsuits against GMC.  I am only pointing out what appears to be a safety related problem with this particular meter. 
 
Not sure what you feel I am blowing smoke about.   Logic levels vary a fair amount.  We don't all play with 5V logic.  As I mentioned, you may still see cases of high voltage CMOS.  The feature is very sensitive to input levels.   I doubt there would be many cases where someone would actually be able to use it.    Not to mention is has what appears to be a firmware bug where it does not work at all.   I ran into it when I first powered up the meter and tried to measure frequency.  I thought the meter was damaged out of the box then realized what was going on.   It has happed several times since.   I have not looked into what causes it to get into this mode.  The meter can be off, just sitting on the bench, turn it on and try to measure frequency and the problem shows up. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 05, 2017, 11:51:33 am
The fan boys simply never give up  : :palm:
We know that Joe loves his Brymen 869, but that's no excuse to pin labels on people. Kristallnacht is in the past.

What the fuck are you on about ?
Why can't you just accept the valid issues with this meter ?
Just because a company has a great reputation does NOT mean that they can't things wrong.
Gossen have already said they are going to sort it out.  :palm:

GET OVER IT !!

3DB
It will be interesting to see if Gossen comes up with a solution and what it is. I think they could fix the frequency input problem with firmware.  The latching relay state change could be improved with firmware and using a shield around the relay.   The proximity effect and sensitivity to the charged cloth can also be reduced by adding a shield.   

I'm not sure what it would take to make the MHz input less sensitive to the voltage levels but I would open up the range as well.  I wonder if there is a way they could improve the slow auto range and get that tri-display to do something useful.   

Personally I would add some sort of protection for that external power connector when it's not in use.  Include the software and cable or at least don't make it so obvious that you are putting the screws to your customers (lower the price).  $70 for a some rubber and a magnet, really?   
Title: testers for mains use?
Post by: evava on June 06, 2017, 06:36:23 pm
Joe, when you have finished with Gossen, what about to test some meters (or better testers) which are directly meant to poke into mains with.
Would you be so kind to test this two UNI-T testers, which I often use for mains (instead of multimeters), but after seeing so much videos from you I am now not so sure if they are enough safe:

UT15C: https://www.amazon.com/Multifunction-Voltage-Tester-UNI-Trend-UT15C/dp/B0053X7HI2 (https://www.amazon.com/Multifunction-Voltage-Tester-UNI-Trend-UT15C/dp/B0053X7HI2)
UT18C: https://www.amazon.com/Voltage-Continuity-Indication-Battery-Detection/dp/B01AJJA6S2 (https://www.amazon.com/Voltage-Continuity-Indication-Battery-Detection/dp/B01AJJA6S2)

Technically they are multimeters IMHO (without Amp range - like Fluke 101).

Manual UT15C https://www.soselectronic.cz/a_info/resource/l/UT15ABC.pdf (https://www.soselectronic.cz/a_info/resource/l/UT15ABC.pdf) does not mention CAT ratings, only "overvoltage 690V" and "Constructed in accordance with IEC 61010 and IEC 61243-3".

And UT18C according to manual http://www.batronix.com/pdf/uni-t/UT18ABCD-manual-en.pdf (http://www.batronix.com/pdf/uni-t/UT18ABCD-manual-en.pdf) has got CAT III 690V and CAT IV 600V.
 
What do you think about it?
Title: Re: testers for mains use?
Post by: Fungus on June 06, 2017, 07:06:46 pm
Joe, when you have finished with Gossen, what about to test some meters (or better testers) which are directly meant to poke into mains with.
Would you be so kind to test this two UNI-T testers, which I often use for mains (instead of multimeters), but after seeing so much videos from you I am now not so sure if they are enough safe:

UT15C: https://www.amazon.com/Multifunction-Voltage-Tester-UNI-Trend-UT15C/dp/B0053X7HI2 (https://www.amazon.com/Multifunction-Voltage-Tester-UNI-Trend-UT15C/dp/B0053X7HI2)
UT18C: https://www.amazon.com/Voltage-Continuity-Indication-Battery-Detection/dp/B01AJJA6S2 (https://www.amazon.com/Voltage-Continuity-Indication-Battery-Detection/dp/B01AJJA6S2)

Technically they are multimeters IMHO (without Amp range - like Fluke 101).

Like this?

https://www.youtube.com/watch?v=i8pRlvgJw-o (https://www.youtube.com/watch?v=i8pRlvgJw-o)

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 06, 2017, 07:20:39 pm
A special drop test for Fungus

https://www.youtube.com/watch?v=hE8cJuza_2Q (https://www.youtube.com/watch?v=hE8cJuza_2Q)

I'm so proud.  :)

I guess the rubber helps a lot in those sort of drops.
Title: Re: testers for mains use?
Post by: evava on June 06, 2017, 07:25:23 pm

Like this?

https://www.youtube.com/watch?v=i8pRlvgJw-o (https://www.youtube.com/watch?v=i8pRlvgJw-o)

Oops, thank you!  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 07, 2017, 12:21:04 am
A special drop test for Fungus

I'm so proud.  :)

I guess the rubber helps a lot in those sort of drops.

Normally, I would have never considered doing anything like this.  I'm not sure if the rubber just added weight and increased the shock or if it helped to soften it.  Hard to say without instrumenting it.  We can go with your guess that the rubber helps a lot. 

Evava, there is a spreadsheet linked to the very first post in this thread that contains every meter I have looked at so far.   I am guessing you did not watch the last few videos or fell asleep, as I mentioned running the 15C. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 07, 2017, 11:41:12 am
I did receive an email from GMC.  It seems they now understand my concern with the meter's mechanical relay.   

Quote
We appreciate your findings about the sensitivity of the relay to magnetic fields and the possibility for a wrong AC voltage display. The relay has not caused a safety concern so far, because the possibility for a wrong AC display was not known. This is new to us and we shall have a risk assessment concerning this.

I would like to read the risk assessment.  It may be very insightful. 

Quote
All your findings are under investigation in R&D. The target is of course an improvement of the device concerning its sensitivity to external electromagnetic fields. The solution shall of course become available for the serial production of the device, thus we cannot promise it short term, but we are targeting to make it available a.s.a.p.

If I hear anymore from them, I will let you know.  Sounds like it may be a while.     
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on June 07, 2017, 12:09:06 pm
"Sounds like it may be a while."

Yep, like at the end of Raiders of the Lost Ark, when Indy was told "Top Men" were working on the Ark   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: lem_ix on June 07, 2017, 01:43:26 pm
Haha you may have convinced Gossen but the fanboys won't budge :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 07, 2017, 11:31:00 pm
I took the Ultra back apart and saw no signs of anything starting to breakdown.   Made a few changes to it while I had it apart. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2017, 02:56:37 am
The shield in the above pictures did not work so well.  Back to the drawing board.  Here is the final shield and other mods in operation.   

https://www.youtube.com/watch?v=Jf_9XWL3TD8 (https://www.youtube.com/watch?v=Jf_9XWL3TD8)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2017, 04:59:43 pm
Big thanks to Dave for sending one of the only two 121GWs he has.  Looks like it will arrive next week.   

Will it pass the grill starter?  Stay tuned and find out.
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on June 09, 2017, 05:39:40 pm
Big thanks to Dave for sending one of the only two 121GWs he has.  Looks like it will arrive next week.   

Will it pass the grill starter?  Stay tuned and find out.

But will it survive the 5 story drop test? :)
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on June 09, 2017, 07:07:32 pm
I want to know if it'll survive a 1.21 GW burst.   Joe, can you arrange to perform that test?   :-DD


Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on June 09, 2017, 09:33:47 pm
The shield in the above pictures did not work so well.  Back to the drawing board.  Here is the final shield and other mods in operation.   

https://www.youtube.com/watch?v=Jf_9XWL3TD8 (https://www.youtube.com/watch?v=Jf_9XWL3TD8)

Nice work!
Gossen will no doubt be offering a "joeqsmith" update/fix for $250.00, which may include the dust plug.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2017, 11:23:54 pm
Nice work!
Gossen will no doubt be offering a "joeqsmith" update/fix for $250.00, which may include the dust plug.

Let's not encourage the gent to expect a cut for the JQS Mod, and leave his current day job,

going hungry in the street waiting for a royalty cheque in the mail   
                                                                  "Will stress test and mod multimeter for food"   :'(

Even at $250, I would not take them up on the offer.  It would have to be for free and as soon as it arrived, you know what I would do with it?  You should!  They would have to be VERY confident in their changes to want to send one to me and all I have to say is they better do their homework before they would even consider it.   

Again, I run the meters out of my own interest and just share my findings.  If I were doing it to make money, my current business model is flawed!  And again, I want to thank everyone who has offered to help.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2017, 11:29:44 pm
I want to know if it'll survive a 1.21 GW burst.   Joe, can you arrange to perform that test?   :-DD


Sent from my iPhone using Tapatalk

Maybe tie it to some kite string during the next big storm?   

Let's start with the grill starter.  EVERY meter ever made should at least handle that.   
Title: Re: Handheld meter electrical robustness testing.
Post by: zaoka on June 09, 2017, 11:40:02 pm
Next to UL should be JS  :-+ :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on June 10, 2017, 01:16:25 am
Again, I run the meters out of my own interest and just share my findings.  If I were doing it to make money, my current business model is flawed!  And again, I want to thank everyone who has offered to help.

You mean you take a loss on an individual basis but make up for it in volume?   :-DD



Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 10, 2017, 05:08:41 am
One more follow up video.  Using the Ultra to measure simulated high ESR capacitors.   Wrist straps and fabric.  Transient testing the modified meter at 12KV.     

https://www.youtube.com/watch?v=gAgtaY5uLyE (https://www.youtube.com/watch?v=gAgtaY5uLyE)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 10, 2017, 09:20:41 am
Somebody's badmouthing joe

https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/msg1229950/#msg1229950 (https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/msg1229950/#msg1229950)

Title: Re: Handheld meter electrical robustness testing.
Post by: P90 on June 10, 2017, 09:27:03 am
Somebody's badmouthing joe

https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/msg1229950/#msg1229950 (https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/msg1229950/#msg1229950)

It's not badmouthing... I'm  saying don't believe everything you read... if I wanted to badmouth, I'd call him a hack...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 10, 2017, 12:28:18 pm
Somebody's badmouthing joe

https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/msg1229950/#msg1229950 (https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/msg1229950/#msg1229950)

It's not badmouthing... I'm  saying don't believe everything you read... if I wanted to badmouth, I'd call him a hack...

Maybe see would have been a better choice as most watch my videos, not read them.

I have yet to see you post anything outside of trolling the forum.   You are certainly welcome to point out what you feel I misrepresented.  You could repeat the tests if you like and show your own data.  Personally I would welcome you bringing something to the table for once rather then all your personal attacks on me and others over such trivial things.   
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on June 10, 2017, 12:35:35 pm
I have yet to see you post anything outside of trolling the forum.   You are certainly welcome to point out what you feel I misrepresented.  You could repeat the tests if you like and show your own data.  Personally I would welcome you bringing something to the table for once rather then all your personal attacks on me and others over such trivial things.   

They're just haters Joe. I appreciate your work. It's information. New information is always a good thing.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 10, 2017, 01:45:04 pm
In that last clip I show how the 10Meg resistance was fairly low.  I did not do a very good job keeping things clean when I had it apart to make the last changes.   A little TLC with some cleaner and the resistance is back to normal. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 10, 2017, 10:52:01 pm
That's quite a difference a little cleaning makes. I shall keep that in mind.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 12, 2017, 04:20:37 pm
That's quite a difference a little cleaning makes. I shall keep that in mind.

Normally I am pretty good about keeping my hands clean and cleaning the board after I am done.  Just didn't take my time was all.  I does not take much to screw things up.  I thought it would be good to at least show.     

Also, turns out the Ultra can detect a blown fuse while measuring current as long as the open circuit voltage greater than 2.5 or so.  So it works as I would expect. 

Something just arrived all the way from Australia!  I'm pretty excited to have a look.

 

Title: Re: Handheld meter electrical robustness testing.
Post by: imidis on June 12, 2017, 04:22:57 pm
Awesome Joe! Looking forward to that one!
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on June 12, 2017, 04:29:54 pm
Give us an unboxing!
Title: Re: Handheld meter electrical robustness testing.
Post by: Hydrawerk on June 12, 2017, 06:11:24 pm
I am looking forward to Dave's DMM. Who manufactured it?
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on June 12, 2017, 06:16:42 pm
I am looking forward to Dave's DMM. Who manufactured it?

You can start reading from here: https://www.eevblog.com/forum/chat/new-eevblog-branded-multimeter-coming/msg1220835/#msg1220835 (https://www.eevblog.com/forum/chat/new-eevblog-branded-multimeter-coming/msg1220835/#msg1220835)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 01:56:53 am
I have been playing around with the pre-released 121GW and am working with Dave to get an idea on how he would like to proceed.    Because the meter is still being developed it makes things a little more difficult.  So please be patient while we sort things out.   

I will come out and say the meter is pretty cool and has a lot more features than my foam replicas!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 13, 2017, 02:12:05 am
No worries, Joe. Looking forward to however much you can accomplish pre-release, and more after release. :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on June 13, 2017, 02:13:00 am
Are you going to do a review before Dave does?
Or blow it up before it gets released... >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 03:47:01 am
Because the meter is not release and still being developed, I am unable to do a detailed review.  Dave has suggested the we basically run the tests on it and see how it does.  The problem with this is I need to do some sort of functional test to know if the meter has changed after testing.  So some sort of mini-review is in order if anything just to show that the meter basically works.   

I am thinking we would put it through all the same tests I normally keep metrics on.   It would give Dave some idea how the meter will stack up against the others I have looked at. 

Yes, it could very well get damaged before it gets released.  That's the nature of running the tests. 

Because that grill starter has damaged so many UNI-Ts, I plan to run it before using the large gun.  This assumes it has survived the AC line test. 

Just one transient off the grill starter took out the UNI-T UT181A because of a poor layout, where the EEVBLOG rebranded Brymen BM235 has been unstoppable and recently was exposed to a 12KV transient.   Where does the 121GW fit?
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on June 13, 2017, 09:35:25 am
LOL! I love it how you have the grillstarter sitting ready to ignite. I'd just note this unit on your spreadsheet as "121GW prototype" so no one will complain if their unit turns out to behave differently. To me it seems quite obvious some kind of functional test is needed, so maybe Dave can comment on functionality he thinks is undesirable to review (en therefore test). I don't think Dave will be particularly obstructive in this respect.  ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 02:16:01 pm
LOL! I love it how you have the grillstarter sitting ready to ignite. I'd just note this unit on your spreadsheet as "121GW prototype" so no one will complain if their unit turns out to behave differently. To me it seems quite obvious some kind of functional test is needed, so maybe Dave can comment on functionality he thinks is undesirable to review (en therefore test). I don't think Dave will be particularly obstructive in this respect.  ;)

I think after showing the output of the grill starter and how it compares with the IEC standard, and yet damaging so many UNI-T meters, people will want to see if it will damage the 121GW. 

Yes, this pre-production meter will need to be clearly marked in the spreadsheet.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 13, 2017, 02:36:06 pm
I think after showing the output of the grill starter and how it compares with the IEC standard, and yet damaging so many UNI-T meters, people will want to see if it will damage the 121GW. 

I definitely do.

I'm not holding my breath though. I suspect it'll survive.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 13, 2017, 02:44:01 pm
Mr. JQS:

Is it possible/practical/insane to incorporate a real world 'carpet surf' Pass or Fail in your meter testing procedures? 

or fast removal of a pullover garment that charges up ?

Not really practical. It depends too much on the weather, etc.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 03:18:04 pm
Mr. JQS:

Is it possible/practical/insane to incorporate a real world 'carpet surf' Pass or Fail in your meter testing procedures? 

or fast removal of a pullover garment that charges up ?

Not really practical. It depends too much on the weather, etc.

Agree.  Then again, drop testing a meter on the desk also has it's share of variables but I gave it a go just for you.  :-DD :-DD 

When I was attempting to design my own gun from scratch (not for the faint of heart) I showed a transient when I just sat down in my chair without a strap.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 13, 2017, 03:22:32 pm
Not really practical. It depends too much on the weather, etc.

Agree.  Then again, drop testing a meter on the desk also has it's share of variables but I gave it a go just for you.  :-DD :-DD 

But it's reasonably repeatable.  :popcorn:

You didn't do the screwdriver test though. I thought something like a large screwdriver handle on the table could concentrate the force and give it something to spin/bounce off.

Maybe we need a robot arm to hurl meters against walls.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 03:55:59 pm
I was waiting for you to write a detailed test plan. 
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on June 13, 2017, 04:16:06 pm
I think it would be good if you included the  'Mrs Smiths Fabric Test' in all future meter tests.
It can be the new electrostatic reference source.  ;D

3DB



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 04:18:43 pm
I think it would be good if you included the  'Mrs Smiths Fabric Test' in all future meter tests.
It can be the new electrostatic reference source.  ;D

3DB

That may not be a bad idea.  The reason it came up with the Gossen was I had just never seen a meter that would wander that bad with the inputs shorted. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 13, 2017, 04:42:10 pm
I was waiting for you to write a detailed test plan.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=323667;image)

It would help to know the orientation of the moving parts inside the relay.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 05:24:06 pm
Now you know that's not a detailed set of test requirements. 
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on June 13, 2017, 05:36:52 pm
Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)
Title: Re: Handheld meter electrical robustness testing.
Post by: Monkeh on June 13, 2017, 06:04:32 pm
Now you know that's not a detailed set of test requirements.

It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)

I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on June 13, 2017, 08:32:12 pm
Now you know that's not a detailed set of test requirements.
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)
I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!
What were you measuring?  ???

[...]
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)
Yeah, but it still does happen. I think it is a fair requirement for a handheld meter to be able to survive falling without changing cal by ~30x as this one did. I can imagine the situations in which it is most important the value is correct (like when measuring the presence of mains) it is most likely the meter will fall (like when doing building activities or installation work). I can't remember when I last dropped a multimeter, but I don't do the aforementioned things.
Title: Re: Handheld meter electrical robustness testing.
Post by: Monkeh on June 13, 2017, 08:54:48 pm
Now you know that's not a detailed set of test requirements.
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)
I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!
What were you measuring?  ???

I was working on a horse lorry. Farms are dirty places y'know. I believe at the time I was trying to get the ******* to start.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 13, 2017, 09:04:03 pm
Now you know that's not a detailed set of test requirements.
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)
I've very nearly dropped a meter into a cow pat. Wouldn't be much of an impact, but it'd definitely affect the measurements!
What were you measuring?  ???

[...]
It's for those with SLIPPERY hands. Can't remember the last time I dropped my meter on a screwdriver, oh wait, now I remember, I've never dropped one, at all. :)
Yeah, but it still does happen. I think it is a fair requirement for a handheld meter to be able to survive falling without changing cal by ~30x as this one did. I can imagine the situations in which it is most important the value is correct (like when measuring the presence of mains) it is most likely the meter will fall (like when doing building activities or installation work). I can't remember when I last dropped a multimeter, but I don't do the aforementioned things.

You saw a meter change 30X after being dropped?   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 14, 2017, 01:01:07 am
Seriously guys, you can calibrate the -carpet surf-  test jig by walking (or 'surfing') across a fixed length of carpet with same slippers or shoes,
both selected to create a suitable electrostatic BANG! to a multimeter.

The brief ON and OFF pullover test can be done in any weather,
I don't expect Mr JQS to keep on a pullover for the duration of a Youtube video during inferno weather conditions

This can be the final word on real world  "Handheld meter electrical robustness testing."  for any meter!  :-+

Assuming it first survives the screwdriver drop and cow pat test    :scared:           (Fluke 28-11 owners will love that s***)   :-DMM
As Fungus mentioned and if you read the couple of papers I had linked in the YT comments, the type of fabric will have a big effect.  So will humidity.  Your test plan is right there with Fungus's drop test.  I think if you do a little research on how the ESD standards evolved (continue to evolve) you may find it interesting. 


Well, it's been another VERY long day of meter testing.  Let me just say from my perspective of running these test, it's one thing to buy a meter that is in production that anyone can buy and then run these potentially destructive tests on it.  Running a meter that you know there are only a very limited number made is a whole different story. If it were my design, I would be all for running it to failure.  I've been in that position many times.   

The video is currently rendering.  Because of the meter not being released yet, my plan is to allow Dave to review it first and make sure there is nothing proprietary being shown.   I've kept things pretty basic and not expecting there to be problems.   So stay tuned, it shouldn't be much longer.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 14, 2017, 02:54:56 am
The video is in Dave's hands now. 

The house was pretty warm today and that LeCroy DSO makes for a small space heater.  I decided to put one of the battery powered Flukes to work.  As beat up as these were, so far they seem to be working fine.  This one needs a new EL after seeing how bright the other one was after replacing it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 14, 2017, 04:22:57 am
Dave reviewed the video and has approved it to be released.  I will allow Dave to comment on the findings.   

https://www.youtube.com/watch?v=X28bwdTBW8g (https://www.youtube.com/watch?v=X28bwdTBW8g)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 14, 2017, 04:43:35 am
Dave reviewed the video and has approved it to be released.  I will allow Dave to comment on the findings.   

Thanks Joe, I commented on the Youtube video but will repeat that here:

SPOILER ALERT:
Thanks for the testing Joe. We think we may have uncovered a potential cause of failing at the 2kV impulse and will be looking into that. It was most likely the 2kV impulse on the ohms range that caused the failure at that point, as there is no mechanism whereby the Volts range could potentially fail at that voltage.
The meter is still under development as you mention, so changes are still on-going.
Even if it passed all the impulse tests, it will never be the best choice for those looking for the best high energy rated industrial meter (hence the lack of CAT IV rating, only CAT III, 600V max).
It is also being ETL certified to ensure full safety compliance of course.?
Title: Re: Handheld meter electrical robustness testing.
Post by: imidis on June 14, 2017, 04:51:31 am
Thanks Dave and Joe :)
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on June 14, 2017, 05:00:25 am
Even if it passed all the impulse tests, it will never be the best choice for those looking for the best high energy rated industrial meter (hence the lack of CAT IV rating, only CAT III, 600V max).

What??   But ... but ... 1.21 GW!!!

Surely it'll pass the kite string test...

:-DD




Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 14, 2017, 05:05:23 am
Even if it passed all the impulse tests, it will never be the best choice for those looking for the best high energy rated industrial meter (hence the lack of CAT IV rating, only CAT III, 600V max).

What??   But ... but ... 1.21 GW!!!

I'll pay that!
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on June 14, 2017, 02:24:16 pm
Looks like I'll be acquiring one, once they are released.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 14, 2017, 03:27:41 pm
Will David L. Jones be the next John Fluke?  :popcorn:

I think purple would be a better color.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on June 14, 2017, 06:24:11 pm
Troubleshooting 61010 impulse testing fails... don't impulse test because it's destructive and good luck finding out where the breakdown occurred.

My method is to use a HV power supply made of a car ignition coil and PWM circuit to generate mild HV. Or a high-pot tester.

Apply this to the circuit and you can hear/see the corona or make an arc. If the breakdown location is really elusive, do it in the dark but keep your nose away  :o
If you keep the HV applied for a long time (many seconds), ozone buildup occurs and the air breaks down at a lower level which can be misleading.
You can also place Kapton tape in the areas you guess the breakdown is occurring and look for results.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 16, 2017, 08:53:59 am
Of course it's fast, it uses a flux capacitor!

(just don't go over 88Hz)


Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 16, 2017, 08:59:12 am
Troubleshooting 61010 impulse testing fails... don't impulse test because it's destructive and good luck finding out where the breakdown occurred.

Yes, tracking down the exact mechanism of the failure like this takes a huge amount of time, effort, and busted meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 16, 2017, 12:36:35 pm
The snowball test is a new one.  :popcorn:

https://www.youtube.com/watch?v=wkrbohiuUwU&feature=youtu.be&t=32m10s (https://www.youtube.com/watch?v=wkrbohiuUwU&feature=youtu.be&t=32m10s)


Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 16, 2017, 12:37:53 pm
Of course it's fast, it uses a flux capacitor!

(just don't go over 88Hz)
The CEM meters I have are really bad.  So is the TPI. 

Whoosh?
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on June 16, 2017, 06:18:04 pm
[...]
You saw a meter change 30X after being dropped?
The Metrahit changed about that ratio after being subjected to a magnetic field (I must admid I have not looked up the exact figure). I had assumed the drop test Fungus suggested was intended to provoke the relay changing this same way, that is why I mentioned it. Reading back the comments this might not have been the case. Excuse me for causing confusion...  :-[
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 16, 2017, 10:13:59 pm
[...]
You saw a meter change 30X after being dropped?
The Metrahit changed about that ratio after being subjected to a magnetic field (I must admid I have not looked up the exact figure). I had assumed the drop test Fungus suggested was intended to provoke the relay changing this same way, that is why I mentioned it. Reading back the comments this might not have been the case. Excuse me for causing confusion...  :-[
This makes much more sense.  Thanks for clearing it up.  To be clear the ratio would be dependent on the input.  The higher in voltage, the larger the ratio because the meter just clamps it.  The PTC will just continue to drop more an more voltage.    And of course, the relay did not change states in the drop testing (I use that word very loosely)  I did but that does not mean that it can't happen.  That's why I suggest the shield does not solve the root problem.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on June 16, 2017, 11:12:15 pm
No problem, sorry for that. ;D I hadn't studied the exact workings of the relay, and just threw in the 30x remembering seeing about 4V when plugging into the 120V mains. The clamping behaviour is actually even worse, because it will then show roughly the same 4V when plugging it in to a way higher voltage than that.  :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 16, 2017, 11:58:41 pm
No problem, sorry for that. ;D I hadn't studied the exact workings of the relay, and just threw in the 30x remembering seeing about 4V when plugging into the 120V mains. The clamping behaviour is actually even worse, because it will then show roughly the same 4V when plugging it in to a way higher voltage than that.  :palm:
Yes, that is correct.   I have not heard anymore from them but sure would like to see that risk assessment. 



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 17, 2017, 06:00:32 pm
Has anyone done any tests on the fuse kits Dave is offering?  I am interested in comparing data.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 17, 2017, 08:48:58 pm
Video showing the 400mA ASTM fuse.
https://www.youtube.com/watch?v=Rlv0kwz8MW4 (https://www.youtube.com/watch?v=Rlv0kwz8MW4)
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on June 17, 2017, 10:58:58 pm
I probably would have done it in the same manner anyway but for a minute there you had me worried using the Dremel free hand in that way, I haven't tried it with those ceramic fuses yet but with most of the other glass fuses you can just heat up the metallic tips with a lighter so as to melt the glue for removal of the ends, I have had to do this out in the field on the odd occasion but don't tell anybody.   ;) :-X

Also, and I know you have mentioned it in the past but those scratches on the Uni-T meter are just horrendous and not getting any better with time, I hope they are taking notice of your videos and how badly these screens are holding up, additionally it looks like somebody could do with a hair cut.    :-/O :)
Title: Re: Handheld meter electrical robustness testing.
Post by: oh2hyt on June 18, 2017, 01:52:33 am
How close power measurement matches if you change 181A measure voltage between fuse input and amps jack of 121GW?

Also interested if 121GW does voltage measurement for power calculaltion referenced to amps jack or common jack (and estimates full burden voltage for calculation, or does it measure also full burden voltage)?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 18, 2017, 02:30:51 am
Anyone else watch bigclive's last video and think it was going to be the end of that CEM meter?

https://www.youtube.com/watch?v=FbAxn5dgoic (https://www.youtube.com/watch?v=FbAxn5dgoic)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 18, 2017, 02:48:21 am
Yeah, I jumped almost as high as his cats, despite knowing what was coming. :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on June 18, 2017, 03:32:04 am
Once I heard "made for bad boys and girls", half way through video, I immediately began to wonder if JQS is coming up with some new MM testing protocols? If so, DYNAMITE!!! :scared:
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 03:55:50 am
In the mean time, someone was asking about how Dave could justify the 121GW as a $200 class meter.   The meter has a lot of unique features.    Here is a sneak peek of the VA feature being used to measure the power dissipation of the 400mA ASTM fuse.  Don't tell Dave I posted this. 

https://www.youtube.com/watch?v=bn9m2sNmdw8 (https://www.youtube.com/watch?v=bn9m2sNmdw8)

There was an error in your system setup here.
The error you are seeing was because you are not taking into account the insertion of the 121GW (and hence the small burden voltage of the 121GW) into your measurement. Your UT181 is not measuring at the same ground node a the 121GW is.
So it's a system connection error, not a meter error.
The 121GW can display it's own burden voltage (unique feature), but not in power measurement mode. But if you added that burden voltage and added to the voltage on the UT181 you should find that the two reading should match.?
Or of course simply connect the UT181 ground to 121GW ground.
This is why it was spot on at the low voltage, and then got progressively more error as you increased the current.?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 18, 2017, 04:24:38 am
In the mean time, someone was asking about how Dave could justify the 121GW as a $200 class meter.   The meter has a lot of unique features.    Here is a sneak peek of the VA feature being used to measure the power dissipation of the 400mA ASTM fuse.  Don't tell Dave I posted this. 

https://www.youtube.com/watch?v=bn9m2sNmdw8 (https://www.youtube.com/watch?v=bn9m2sNmdw8)

There was an error in your system setup here.
The error you are seeing was because you are not taking into account the insertion of the 121GW (and hence the small burden voltage of the 121GW) into your measurement. Your UT181 is not measuring at the same ground node a the 121GW is.
So it's a system connection error, not a meter error.
The 121GW can display it's own burden voltage (unique feature), but not in power measurement mode. But if you added that burden voltage and added to the voltage on the UT181 you should find that the two reading should match.?
Or of course simply connect the UT181 ground to 121GW ground.
This is why it was spot on at the low voltage, and then got progressively more error as you increased the current.?

Funny, what you are calling an error in my setup, I was calling an error in the calculations.  Thanks for jumping in as I did not want to answer oh2hyt because I knew they were correct.  I just assumed this was a missing firmware calc.   

I was expecting the meter to measure the power at the load and would include the burden voltage as part of that calculation which is why it is connected this way.  Yes, if I wanted to measure the power dissipated by the load plus the meter, you are both correct and the three meters read very close.   I had tested it up to around 50 Watts (5A 10V sort of range).   I have not looked at AC.   

So, to be clear this is really what the plan is?  Not to display load power by compensating for the burden? 
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 04:52:07 am
Funny, what you are calling an error in my setup, I was calling an error in the calculations.  Thanks for jumping in as I did not want to answer oh2hyt because I knew they were correct.  I just assumed this was a missing firmware calc.   

I was expecting the meter to measure the power at the load and would include the burden voltage as part of that calculation which is why it is connected this way.  Yes, if I wanted to measure the power dissipated by the load plus the meter, you are both correct and the three meters read very close.   I had tested it up to around 50 Watts (5A 10V sort of range).   I have not looked at AC.   

So, to be clear this is really what the plan is?  Not to display load power by compensating for the burden?

I don't recall when we discussed this way back, but IIRC it wasn't possible to measure the burden voltage in power measurement mode for some reason, hence there was no data to compensate.
You could of course guess and fudge in a number and do it that way, but is guessing better than not including it?
What if you actually want the entire power consumption? e.g. for PSU efficiency testing, which is a major use I envisaged for this function.
Ideally you'd want to select between the two modes.
I'll take another look at it though.
The second display can show the volts or amps BTW, just keep pressing SETUP to get to it, yes confusing, need to fix this in the firmware.
And IIRC the Gossen Energy doesn't compensate, but it's been a long time since I used it.
Title: Re: Handheld meter electrical robustness testing.
Post by: oh2hyt on June 18, 2017, 04:57:17 am
The 121GW can display it's own burden voltage (unique feature), but not in power measurement mode.
Sounds really cool feature.

Should power measurement have setting to include or exclude power used by meter? Sometimes you want measure power coming from supply, sometimes power consumed by device under test. There is ofc problem of test leads and connections wasting some power that meter can't exclude from measurement.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 18, 2017, 05:11:33 am
I don't recall when we discussed this way back, but IIRC it wasn't possible to measure the burden voltage in power measurement mode for some reason, hence there was no data to compensate.
You could of course guess and fudge in a number and do it that way, but is guessing better than not including it?
I'll take another look at it though.
The second display can show the volts or amps BTW, just keep pressing SETUP to get to it, yes confusing, need to fix this in the firmware.

That seems like a bit of a miss or maybe that's just my perception.  If I need to make a separate measurement and hand calculate, the feature becomes less useful.   Maybe most people are interested in wanting the total power rather than at the load.  Both would be my preference.     

I had no idea about being able to read the current/voltage.  Just tried it and seems to work.  Really, UI is not too bad.  Needs a little polish is all.   

Also,  I'm curious what your thoughts are on the 400mA ASTM fuses.  If you have some that are out of a different lot, I would be interested in knowing if their cold resistance changes a fair amount.   That 2 ohms I measured seems a bit high.   
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 05:21:23 am
I had no idea about being able to read the current/voltage.  Just tried it and seems to work.  Really, UI is not too bad.  Needs a little polish is all.   

The UI has had very little spit'n'polish added yet.

Quote
Also,  I'm curious what your thoughts are on the 400mA ASTM fuses.  If you have some that are out of a different lot, I would be interested in knowing if their cold resistance changes a fair amount.   That 2 ohms I measured seems a bit high.

I have many boxes of them, will need to do some measurements.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 06:13:20 am
Quote
Also,  I'm curious what your thoughts are on the 400mA ASTM fuses.  If you have some that are out of a different lot, I would be interested in knowing if their cold resistance changes a fair amount.   That 2 ohms I measured seems a bit high.
I have many boxes of them, will need to do some measurements.

I had a 600mA version here and measured that at a smidge under 1ohm. Above the 0.75ohm typical datasheet value.
Title: Re: Handheld meter electrical robustness testing.
Post by: Wytnucls on June 18, 2017, 06:55:14 am
The 121GW can display it's own burden voltage (unique feature), but not in power measurement mode.
Sounds really cool feature.

The Fluke 867B does something similar, displaying the value of the shunt for the mA and uA ranges. No power measurement though.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 07:16:00 am
20 units from the same box:

(http://i.imgur.com/6oRNpOz.png)

Datasheet spec is 1.65. So seems they are specifying the lowest typical measured value, and it can be higher based on contact and wire tolerance etc. But not really lower.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on June 18, 2017, 08:33:06 am
Betting the cold resistance relates in some way to the radial position of a spool of wire that supply the fuse elements before cutting. Looks like there is a slight stretch in the wire with it having some cyclic change in either width of slitting or thickness in the original sheet, and this is carried through to the order in which they were packed in the box with some faithfulness. No other way to get that cyclic curve in resistance with them coming out the box in order.

When using film that subtle cyclic change can be a real problem at times, if the tolerance is tight or just enough to get you out of the one end of the tolerance window.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 08:59:37 am
Betting the cold resistance relates in some way to the radial position of a spool of wire that supply the fuse elements before cutting. Looks like there is a slight stretch in the wire with it having some cyclic change in either width of slitting or thickness in the original sheet, and this is carried through to the order in which they were packed in the box with some faithfulness. No other way to get that cyclic curve in resistance with them coming out the box in order.

Can't guarantee that I tested them in order, took out the first row of 10, then the second row. Some shuffling may have happened.
Interesting hypothesis, and something like that wouldn't surprise me.

I almost see two distinct value levels with some tolerance around each one. Wasn't really one smack in the middle.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 18, 2017, 11:12:38 am
Anyone else watch bigclive's last video and think it was going to be the end of that CEM meter?

https://www.youtube.com/watch?v=FbAxn5dgoic (https://www.youtube.com/watch?v=FbAxn5dgoic)

Love the serial number!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 18, 2017, 03:36:56 pm
Datasheet spec is 1.65. So seems they are specifying the lowest typical measured value, and it can be higher based on contact and wire tolerance etc. But not really lower.

That's interesting.  If I look at the 2014 document, they do indeed show 1.65 typical.  However, the document I show in the video from 2016 shows 1.5.   See attached. 
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 18, 2017, 10:50:34 pm
Datasheet spec is 1.65. So seems they are specifying the lowest typical measured value, and it can be higher based on contact and wire tolerance etc. But not really lower.
That's interesting.  If I look at the 2014 document, they do indeed show 1.65 typical.  However, the document I show in the video from 2016 shows 1.5.   See attached.

Interesting.
I've asked them to explain why our measurements are higher than the datasheet "typical".
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 19, 2017, 04:29:07 am
Reply from ASTM:

Quote
Sorry for the mistake.
I checked our internal spec, the spec of HV620.0.4 had been 1.5-2.2Ohms since 2015, and we had submit to and approved by the DMI manufacturer by that time.
Since the HV620 series fuse sold to DMI manufacturer only, I believe the mistake caused by forgot to updated the public datasheet after approval by DMI manufacturer internally.
 
Anyway, the fuses we sold to you are correct and the electrical performance meet spec.
Here I attached the updated datasheet with correct resistance value.

Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on June 20, 2017, 01:42:53 pm
[...] I tend to look for the more obvious answers.   :-DD
[...]
Well, that seems to have been the proper thing to do. :-DD Once again I love it when a company returns proper info when asked about some strange behaviour/result. Credits to them!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 20, 2017, 10:52:54 pm
Reply from ASTM:

Quote
Sorry for the mistake.
I checked our internal spec, the spec of HV620.0.4 had been 1.5-2.2Ohms since 2015, and we had submit to and approved by the DMI manufacturer by that time.
Since the HV620 series fuse sold to DMI manufacturer only, I believe the mistake caused by forgot to updated the public datasheet after approval by DMI manufacturer internally.
 
Anyway, the fuses we sold to you are correct and the electrical performance meet spec.
Here I attached the updated datasheet with correct resistance value.

Thanks for checking into this. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 21, 2017, 02:25:19 am
Is len = 0 the reason the spreadsheet shows the interval to be zero seconds? :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 21, 2017, 02:53:52 am
Ah, I guess they have the wait at the beginning of the loop.

@EEVBlog: Dave, it'd be good to have the actual interval, instead of 0, output to the file when setting len = 0.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 21, 2017, 11:25:13 am
@EEVBlog: Dave, it'd be good to have the actual interval, instead of 0, output to the file when setting len = 0.

I agree.  Being a pre-production unit and knowing they are working on the UI, they may have already changed it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 21, 2017, 11:37:52 am
@EEVBlog: Dave, it'd be good to have the actual interval, instead of 0, output to the file when setting len = 0.

I agree.  Being a pre-production unit and knowing they are working on the UI, they may have already changed it.

And if not, it's a suggestion.  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 21, 2017, 04:32:49 pm
Yep, figured I'd post it, just in case. :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 22, 2017, 03:07:32 am
It also sounds like it may be dying before it can unload its buffer. Either way, something for the 121 team to check out. Good pre-release testing.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 22, 2017, 08:38:39 pm
Thanks for the update, Joe. I agree it's too early for videos and probably best to just continue reporting the findings to Dave so they can take care of them.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 22, 2017, 09:05:04 pm
With the right firmware ... this meter looks like a winner!

Who needs a Fluke 87V?

(apart from people who want to get past building security guards)

Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on June 22, 2017, 11:42:19 pm
With the right firmware ... this meter looks like a winner!

Who needs a Fluke 87V?

(apart from people who want to get past building security guards)

Because the 87V is likely to survive better if you whack the security guard over the head with it?   :-DD




Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 23, 2017, 02:35:11 am
My TPI194II was damaged from the stupid AC line test.  One of the symptoms was the resistance with an open was a few Meg.  I had looked into repairing it but found that the problem was two pins of the front end IC were leaking a lot of current.  I tried to buy a new IC but could not find a source. TPI had offered to replace the meter but it really was not their fault the meter was damaged.   

I looked at again today.  Basically, meters will normally have a multiplexer stage to switch the resistors for the attenuator.  The resistors are normally off chip.  The resistors can normally be switched at all the different voltages available to the IC.   On this IC, when a resistor is not selected, the output goes high Z. What happened was it was pulling these two pins low (to the battery ground).  So, I added a series diode and trimmed the resistors to compensate for the loss.  It does not work great but at least now those two pins are not dragging the input down.


Here it is with an open set of leads.
 
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 23, 2017, 02:41:45 am
All the functions basically work. Temperature drift would be a problem and really, its a pretty crappy way to bring it back to life.  Why they did not clamp this input, no idea.  It's a fairly expensive meter. Very solid case design.  Has some pretty nice features.  Even certified.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 23, 2017, 03:11:20 am
Thermal couple input, capacitance and AC+DC with the tri-display.   The meter uses TH axial parts for the attenuator.  One of these was replaced with four resistors and a diode to get it trimmed in.  The other catch is that the because the damage pins can no longer sink, you loose the divider function for the voltage mode.   The meter will not display the correct voltages once the input is above 50V (50K count meter).   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2017, 02:44:07 pm
What to do with a damaged pre-production meter?  One day, someone is going to look back on this and say, if they had only left it, it would be worth $1,000,000 on eBay but because of the unoriginal condition, it's now worth $0.01  :-DD

Lots of work to do.
Title: A robustness testing candidate
Post by: ci11 on June 24, 2017, 03:47:11 pm
Hi Joe,

Here is something a little different you should tear down and thoroughly test, the $65 Kill A Watt PS-10 power strip.

It is a normal Kill A Watt with some additional "smarts" built in that appear to be pretty useful for any bench on a budget. Its claims to have a "zero-crossing soft start", settable current limiter, leakage current measurements and a 10-tap output strip for up to 18A is begging your lab to get it the thumbs up. Things I'd like to know are: does it protect as claimed, is it accurate, can it be modded to keep the backlight constantly on.

This has the makings of interesting match between a useful smartie-pants power accessory and the latest word in electrical safety testing!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2017, 04:10:44 pm
Hi Joe,

Here is something a little different you should tear down and thoroughly test, the $65 Kill A Watt PS-10 power strip.

It is a normal Kill A Watt with some additional "smarts" built in that appear to be pretty useful for any bench on a budget. Its claims to have a "zero-crossing soft start", settable current limiter, leakage current measurements and a 10-tap output strip for up to 18A is begging your lab to get it the thumbs up. Things I'd like to know are: does it protect as claimed, is it accurate, can it be modded to keep the backlight constantly on.

This has the makings of interesting match between a useful smartie-pants power accessory and the latest word in electrical safety testing!

I did look at a killawatt some time ago just to see if the numbers they put out were in the ballpark.  Actually, it seemed to do a fairly decent job for the price.  I am sure it could be modified to do what ever you like given enough time, money and brain power.   

I would really have no way of knowing if it could protect as claimed.  For this you really need to look for someone like UL to test it. 

I wonder about the zero cross soft start.  It sounds VERY complex.  Just zero cross detection in general can be a bit of a problem.  There is equipment to test this sort of thing but again, it's way outside of anything I am doing with the meters.   
Title: Re: Handheld meter electrical robustness testing.
Post by: ci11 on June 24, 2017, 04:49:39 pm
Gotcha.

Here is the exact verbage on 'zero crossing" from the Owner's Manual:

"Pressing the ON key will turn power on to the 10 built-in outlets at once. The unit features a spike-free switch function which activates at zero-crossing and will present clean power to your connected appliances. The ON key will illuminate in green. The unit will measure power and the function keys and LCD display will operate."
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2017, 05:10:09 pm
Could just be a TRIAC with a zero crossing driver. 
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on June 24, 2017, 05:50:43 pm
What I was thinking, a simple zero cross snubberless SSR relay in there, nothing more. Wonder what the leakage current of the switch is, those can be a big nuisance with small loads that will either never actually be turned off ( thus negating any power savings) or worse that sit in a voltage level that will either cause a brownout or regular malfunctions that seemingly are random, to totally blowing up the supply as it tries to regulate the switch on time past 100%.

Then also wonder just what they are using as a power supply, and how much it also uses, and how well protected it is as well.

Joe, just for a lark, can you put a few USB wall warts ( not the cheap ones, but ones from reputable manufacturers, because we all know how the cheap ones will fail anyhow) across your line simulator and see what it takes to kill them. My guess is that almost all of them will fail 2kV, but just how badly they do this, and how much they smoke doing so. Most will probably work fine with your test voltage, being universal input devices. You will just need a sacrificial USB voltage monitor and a resistor to draw 100mA to 500mA out of them during the test. Pretty much how they behave in transient conditions, and what a simple mains transient like a motor disconnect on the same branch circuit will affect them.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2017, 06:41:58 pm
I wonder if they don't have a mechanical switch in there for the leakage.   Note the mechanical breaker is still present but I suspect turn off the TRIAC when the current reaches the set point (calling that their programmable breaker).

I did not transient test the killawatt I had but I did have it apart.  Cheap, like you would expect for the price.   


Joe, just for a lark, can you put a few USB wall warts ( not the cheap ones, but ones from reputable manufacturers, because we all know how the cheap ones will fail anyhow) across your line simulator and see what it takes to kill them. My guess is that almost all of them will fail 2kV, but just how badly they do this, and how much they smoke doing so. Most will probably work fine with your test voltage, being universal input devices. You will just need a sacrificial USB voltage monitor and a resistor to draw 100mA to 500mA out of them during the test. Pretty much how they behave in transient conditions, and what a simple mains transient like a motor disconnect on the same branch circuit will affect them.

I would guess they fall under the generic case and are only required to be tested at 1KV line-to-line.   

Again, that sub 20J I test with is basically nothing.  I don't see it ever causing a meter or other device to explode or put out much for smoke.   Really what you would want to do is run these on a real combo generator if you wanted to see something more like the Fluke multimeter videos where they show the cases coming apart.  This is nothing close to what I have setup.   
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on June 24, 2017, 07:45:40 pm
True, but you do have a good audience, and it will be a good thing to show that cheap and nasty really is that, even with limited energy. I think the saving grace for most products these days is the thin wire they use, which acts as an impromptu fuse when the thing fails short circuit. As the fuse is often the thing "designed" out by the cost cutters, and the wire is also "value optimised" to be as thin as possible and as low grade copper as possible this probably is the only thing keeping the fire rate down.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on June 24, 2017, 07:58:04 pm
What about multimeters crashing when connected to HV, to take a voltage measurement?

I've seen a few where the display flickers or the meter reboots when touching the probe to high voltage.
There is a small arc to the probe with the multimeter's input capacitance and I think the EMI burst is too much. Happens consistently around 400-600VDC up, tiny arc.

Long time ago 2002 Fluke had that problem 177,178,179 and did a recall (https://www.cpsc.gov/Recalls/2002/cpsc-fluke-corp-announce-recall-of-digital-multimeters) over the time to reboot making a dangerous situation. Cheap meters never recover, they just look stoned and read garbage.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2017, 11:14:53 pm
What about multimeters crashing when connected to HV, to take a voltage measurement?

I've seen a few where the display flickers or the meter reboots when touching the probe to high voltage.
There is a small arc to the probe with the multimeter's input capacitance and I think the EMI burst is too much. Happens consistently around 400-600VDC up, tiny arc.

Long time ago 2002 Fluke had that problem 177,178,179 and did a recall (https://www.cpsc.gov/Recalls/2002/cpsc-fluke-corp-announce-recall-of-digital-multimeters) over the time to reboot making a dangerous situation. Cheap meters never recover, they just look stoned and read garbage.

I run every meter I look at close to 900 VDC and do not remember ever seeing any problems like you describe with flickers or reboots.  This includes the free meters from HF. 

Most of the meters I look at will have maybe a MOV which makes up the majority of input capacitance. I have only seen one meter where they had a place holder to put a MOV right across the inputs and it was not populated.  :phew:     With DC, I am not sure what this EMI burst is you mention.  Maybe help me out there.    For this flicker, lockup problem, you would need to provide a list of meters you have seen this with.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 25, 2017, 12:29:03 am
Is len = 0 the reason the spreadsheet shows the interval to be zero seconds? :-//

Yes.  Setting it to 1, shows 1 second and it seems to record at that rate.  I tried 999, interesting is that it must wait the 999 second before recording the first time rather then recording the first sample once logging is started, then waiting.

The idea of the "zero" setting was to let the logger record at the max rate of the ADC (5/sec nominal, but will change with the range). otherwise it's in seconds.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 25, 2017, 12:53:55 am
Spent a fair amount of time today looking at the 121GW's circuit board.  That has to be the most heavily populated meter I have looked at. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 27, 2017, 02:09:51 am
It's been a long time since I have really done some major damage to a handheld meter.  Even with all the problems the Gossen has, the one thing it has going for it is it is very robust.  The we have the pre-production 121GW that was damaged before I had a chance to turn things up.   I'm pretty sure this next meter is going to give us a show.   It's another RadioShack.  The last  RadioShack meter I looked at came from 5Ky and that thing was very solid.    Some of these low cost meters have been very impressive.   
 
Catalog number 22-813.  Much smaller than the 121GW.  It's one of those meters that share the voltage input with the current.  Maybe it has some glass fuses in there as well. 
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on June 27, 2017, 02:52:09 am
Look forward to the video!   :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: sleemanj on June 27, 2017, 05:21:39 am
Manual says a single ceramic fuse
https://www.manualslib.com/manual/605149/Radio-Shack-22-813.html?page=21#manual (https://www.manualslib.com/manual/605149/Radio-Shack-22-813.html?page=21#manual)

... Maybe I should have spoiler'd that :-)
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on June 27, 2017, 12:09:45 pm
It's been a long time since I have really done some major damage to a handheld meter.

Joe did you get my PMs? I sent you two and never heard from you.  :(
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on June 28, 2017, 03:36:18 am
Nice job Joe.  Will you go over your mods once the meter is released?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 28, 2017, 04:06:45 am
Nice job Joe.  Will you go over your mods once the meter is released?

I will not be releasing any details about the pre-production meter's design.  Keep in mind that the meter was already more robust than Fluke's golden standard, the 87V.  There may be no reason to improve it if that is what people feel is good enough.  I have been providing Dave with feedback as I have been going over the meter.  I believe they plan to make some changes to address some of my concerns.   

I'm looking forward to seeing the final design.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 08:41:55 am
Am I correct in imagining that the transistors that failed in the Fluke87 are a voltage clamp as shown at the start of EEVBLOG #1000?

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 10:01:03 am
One thing I've been meaning to ask, and this seems an appropriate place, is:

What's the difference between "CAT III 1000V" and "CAT IV 600V"?

The transient voltages and source impedances are the same (8000V, 2 Ohms).


(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327609;image)

(from http://content.fluke.com/promotions/promo-dmm/0518-dmm-campaign/dmm/fluke_dmm-chfr/files/safetyguidelines.pdf (http://content.fluke.com/promotions/promo-dmm/0518-dmm-campaign/dmm/fluke_dmm-chfr/files/safetyguidelines.pdf) )
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on June 28, 2017, 10:11:10 am
@Fungus
The working voltage.

3DB
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 10:29:51 am
@Fungus
The working voltage.

So ... CAT III 1000V is better than CAT IV 600V?  :popcorn:

Why would they even bother with CAT IV then?
Title: Re: Handheld meter electrical robustness testing.
Post by: OldNeurons on June 28, 2017, 11:16:44 am
@Fungus
The working voltage.

So ... CAT III 1000V is better than CAT IV 600V?  :popcorn:

Why would they even bother with CAT IV then?

Read carefully the paper ...
(But, reading carrefully that good paper will not increase your posts counter ...)
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on June 28, 2017, 12:13:04 pm
@Fungus

Maximum working voltage is maximum voltage that can be applied to instrument in normal conditions on a permanent basis.
It is voltage that will not cause any deterioration of instrument by gradual failure of components inside, and will protect user while measuring, if good practice is followed.

So, If highest voltage you are about to measure is 400V, that is your working voltage. And then you buy instrument rated 600V just to be on the safe side..

CAT II, III, IV is resilience to overvoltage transients, and is related to environment you are working in. If you have 12V off the grid solar system on a ranch in country, and have long cables that go overhead, in stormy weather those can pickup huge transients....

So in that case you would need a CAT IV meter while working voltage of 24V would be sufficient, if such thing existed....

By same token, if you are repairing 800V tube amplifiers in your well protected lab in a city, you might need voltmeter with 1000V working voltage, and CAT II, or even CAT I might be fine for you.

Simple as that. Well, not really, but that is basic logic. Trick is that most of the time it is hard to know in what environment you are/will be working, so people prefer to err on the safe side.

Regards,

Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 12:46:56 pm
@Fungus
The working voltage.

So ... CAT III 1000V is better than CAT IV 600V?  :popcorn:

Why would they even bother with CAT IV then?

Read carefully the paper ...
(But, reading carrefully that good paper will not increase your posts counter ...)

Sigh. I'll risk increasing my post counter and try to make it more obvious.

The 'paper' says:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327622;image)

Now ... if we look at the table the source impedance for CAT III and CAT IV is the same so that's not the answer!

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327624;image)

The only thing The Paper says about CAT IV is this:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327626;image)

Now, I'm not completely lazy so I looked up IEC 1010, here: http://www.ni.com/white-paper/2827/en/ (http://www.ni.com/white-paper/2827/en/)

The only thing it says about CAT IV is:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327628;image)

Problem: I don't know what the "other documents" (the ones that cover CAT IV) are, so I thought I'd ask here.

So....

Question:

What's the difference between "CAT III 1000V" and "CAT IV 600V"?

ie. If the "working voltage" of CAT III 1000V is higher and the transients are the same, what's CAT IV all about?

(And why is there no such thing as "CAT IV 1000V"?)
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on June 28, 2017, 01:06:32 pm

(And why is there no such thing as "CAT IV 1000V"?)


There is. Bryman has few meters with that rating. Fluke didn't put it in their whitepaper, probably  because they don't have one...
CAT IV 1000V is rated for 1000V continuous and 12000V transient... That's your difference...

Table attached, source National Instruments...

Cheers.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 01:14:28 pm

(And why is there no such thing as "CAT IV 1000V"?)


There is. Bryman has few meters with that rating. Fluke didn't put it in their whitepaper, probably  because they don't have one...

OK.  :-DD

CAT IV 1000V is rated for 1000V continuous and 12000V transient... That's your difference...

In that case the question becomes: Is CAT III 1000V better than CAT IV 600V?  :popcorn:

(It has a higher working voltage!)

Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on June 28, 2017, 01:25:39 pm
Like I said before, if you don't work on installations directly connected on distribution networks or outside, and you work only in lab, than CAT II is probably enough, as far as overvoltage transient protection is concerned. And if you work with 800V valve amplifiers in your lab, yes, then 1000 CAT II is better than 600V CAT IV....
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on June 28, 2017, 01:38:49 pm
The 121GW goes back in time. 

https://www.youtube.com/watch?v=LMRPe6YaYB4 (https://www.youtube.com/watch?v=LMRPe6YaYB4)

Excellent work Joe.
Thanks for your time and effort.

3DB.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 02:08:39 pm
Like I said before, if you don't work on installations directly connected on distribution networks or outside, and you work only in lab, than CAT II is probably enough, as far as overvoltage transient protection is concerned. And if you work with 800V valve amplifiers in your lab, yes, then 1000 CAT II is better than 600V CAT IV....

OK, I think I get it:

They were drawing a table, four categories, 150V/300V/600V/1000V in each category, stepping up the transients, etc.

Then they ran into a limit, they couldn't decrease the source impedance for CAT IV, it got stuck at 2 Ohms!

Result: CAT III 1000V is better than CAT IV 600V.  :scared:

Is that right?

(and is my Fluke 27, CAT III 1000V really a CAT IV 600V meter, only that it was made before ISO61010-2nd Edition)

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327632;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on June 28, 2017, 02:23:36 pm
The Amprobe 160C does up to 1500V DC and 12kV pulse:
http://www.amprobe.com/amprobe/usen/digital-multimeters/industrial-multimeters-/amp-hd160c.htm?pid=73247 (http://www.amprobe.com/amprobe/usen/digital-multimeters/industrial-multimeters-/amp-hd160c.htm?pid=73247)
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on June 28, 2017, 02:51:03 pm
Result: CAT III 1000V is better than CAT IV 600V.  :scared:

Not really, for indoor work in industrial condition you need at least CAT III for outdoor work you need CAT IV, i.e. the same meter can be used up to 600V outdoor and to 1000V indoor.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 02:59:11 pm
for indoor work ... CAT III for outdoor work you need CAT IV

What's the difference?

Title: Re: Handheld meter electrical robustness testing.
Post by: MosherIV on June 28, 2017, 03:08:46 pm
I think a better description is
Cat III is for after the mains fuse board instead of indoor
Cat IV is for before mains fuse board instead of outdoor

As someone else pointed out, it is to do with the amount of energy available at that point.
ie after the mains fuse board, the fuse should blow and limit the energy
Before the fuse board, you are relying on the substation trips - how many Amps are they going to trip at  :o
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 03:24:03 pm
I think a better description is
Cat III is for after the mains fuse board instead of indoor
Cat IV is for before mains fuse board instead of outdoor

Yes, I know what the description says.

What's the physical difference inside the meter?

Put another way:

Is it possible to make a CAT III 1000V meter which isn't a CAT IV 600V meter?
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on June 28, 2017, 03:27:02 pm
What's the physical difference inside the meter?

Why do you want a difference inside the meter, a 8000V 2ohm transient test qualifies for usage at 1000V indoor (or after the mains breaker) and 600V outdoor (or before the mains breaker).
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 28, 2017, 03:33:46 pm
What's the physical difference inside the meter?
Why do you want a difference inside the meter, a 8000V 2ohm transient test qualifies for usage at 1000V indoor (or after the mains breaker) and 600V outdoor (or before the mains breaker).

I don't want a difference, I want to know if there is a difference.

(consensus seems to be "no").
Title: Re: Handheld meter electrical robustness testing.
Post by: MosherIV on June 28, 2017, 03:45:05 pm
Quote
I don't want a difference, I want to know if there is a difference.


Quote
As someone else pointed out, it is to do with the amount of energy available at that point.
ie after the mains fuse board, the fuse should blow and limit the energy
Before the fuse board, you are relying on the substation trips - how many Amps are they going to trip at  :o

The CAT ratings tell you to what voltage (silly really, should be transient power) the meter will handle.
So both the CAT III and CAT IV ratings apply.

With the CAT III rating the meter can withstand a higher voltage because the amount of power is limited by the local fuse box.

With CAT IV rating the meter withstands a lower voltage because it is now relying on the substation (or whatever) to limit the power.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 28, 2017, 04:55:28 pm
The confusion seems to be exacerbated by strictly comparing numbers. However, the CAT ratings take into account more than just the test numbers. Safety also takes into consideration the operating environment. Since using a meter in a CATIV environment has the potential (heh) to deliver more energy than a CATIII environment, and may be more likely to do so, a greater margin is imposed in the so-called limits by lowering the maximum voltage.

A DMM that passes the 8000-volt 2-ohm transient test is deemed safe at 1000V in environments up to CATIII. When going outside the building to a CATIV environment, the same DMM probably would be fine at 1000V, but the maximum voltage "allowed" is 600 V for additional safety margin.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on June 28, 2017, 07:55:22 pm
What's the physical difference inside the meter?
Why do you want a difference inside the meter, a 8000V 2ohm transient test qualifies for usage at 1000V indoor (or after the mains breaker) and 600V outdoor (or before the mains breaker).

I don't want a difference, I want to know if there is a difference.

(consensus seems to be "no").
The closer you work to the grid (working environment as mentioned) the higher the risk of transients and the greater the risk to the meter and user. Meter voltage derating.  ;)
Power network fuses are larger, supply cabling heavier and so on.

Think impedance of supply.  ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on June 28, 2017, 08:07:56 pm
OMG, I think I've seen 121gw's guts on video... If you still want to keep internals in secret you have to remove the video... and deal with 778 viewers (so far).
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 28, 2017, 10:33:22 pm
Meter voltage derating.  ;)

Yes, "derating". That's the term I was trying to think of earlier.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 29, 2017, 10:26:18 am
FWIW The Fluke 189 has  1000 volts Cat 111 rating on the meter itself, no mention of Cat 4..

It depends on when it was made. The first version of the standard only went up to CAT III. Cat IV was added in the second edition.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=327632;image)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 29, 2017, 04:57:50 pm
Fungus,  I think if you wanted to figure this out, the place to start is by writing one or more manufactures and seeing what they have to say.  Certainly they are the experts. 

It should be obvious that the higher the CAT rating, the more energy available.  Assuming you would understand why they would derate the meter at higher CAT ratings and you really are just asking if any CAT III rated meter is automatically rated to CAT IV 600 and if not, what is the difference. 

Again, turn to the experts but the first thing I would consider (a guess on my part) is that the fuses used would be rated to break a higher energy circuit for CAT IV than CAT III.  Maybe for a CAT III environment for example, they use a 1KV AC/DC 10KA rated fuses.  For CAT IV 600, they may require 20KA and CAT IV 1000 maybe 30KA.  Again, ask the experts.  I am just guessing. 

How did your relay drop test ever work out?   Did you ever buy any and try to get them to change states?    I have not heard any more from Gossen but I expect they don't move very fast.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 29, 2017, 05:05:42 pm
OMG, I think I've seen 121gw's guts on video... If you still want to keep internals in secret you have to remove the video... and deal with 778 viewers (so far).

Good luck reverse engineering it from that video.  :-DD :-DD  Dave had made a video some time back and I think posted a few pictures of it.   I don't think he would want me diving into details about the design and make this public.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 29, 2017, 05:14:40 pm
The Amprobe 160C does up to 1500V DC and 12kV pulse:
http://www.amprobe.com/amprobe/usen/digital-multimeters/industrial-multimeters-/amp-hd160c.htm?pid=73247 (http://www.amprobe.com/amprobe/usen/digital-multimeters/industrial-multimeters-/amp-hd160c.htm?pid=73247)

There are a few meters that I have ran transients to this level and not damaged them.  The Fluke 101, 107, 115 and Brymen BM235.   The HIOKI DT4252 would have electrically survived at this level as well. 

There was another member who repeated the test on a Fluke 101 using a combo surge generator at 12V.  This is the real deal, not my little toy generator. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 29, 2017, 05:29:39 pm
OMG, I think I've seen 121gw's guts on video...
Good luck reverse engineering it from that.

Be sure to include the Flux Capacitor.  :popcorn:

(what's the IEC symbol for that part?)

https://www.xkcd.com/730/ (https://www.xkcd.com/730/)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 30, 2017, 12:05:48 am
Fungus,  I think if you wanted to figure this out, the place to start is by writing one or more manufactures and seeing what they have to say.  Certainly they are the experts. 

It should be obvious that the higher the CAT rating, the more energy available.  Assuming you would understand why they would derate the meter at higher CAT ratings and you really are just asking if any CAT III rated meter is automatically rated to CAT IV 600 and if not, what is the difference. 

Again, turn to the experts but the first thing I would consider (a guess on my part) is that the fuses used would be rated to break a higher energy circuit for CAT IV than CAT III.  Maybe for a CAT III environment for example, they use a 1KV AC/DC 10KA rated fuses.  For CAT IV 600, they may require 20KA and CAT IV 1000 maybe 30KA.  Again, ask the experts.  I am just guessing. 

How did your relay drop test ever work out?   Did you ever buy any and try to get them to change states?    I have not heard any more from Gossen but I expect they don't move very fast.

EVS-EN 61010-2-033:2012
Table AA.1
The short-circuit current is calculated for a 1000 V line-to-neutral voltage and the minimum loop impedance. The values of loop impedances (installation impedances) do
not take into account the resistance of the probe assemblies and impedances internal to the measuring equipment. These short-circuit currents vary, depending on the characteristics of the installation.

For CAT II, they say less than 10kA typical.   CAT III, less than 50kA.   CAT IV, much greater than 50kA.   Wow, 50kA!!   Dave's ASTM 11A fuses are marked 30kA.  I wonder if these would be fine for a CAT IV environment. 

I don't think the test lab knew how to check the Gossen Metrawatt I have for this condition:

16.101 Over-range indication
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage)
displayed by the equipment, the display shall give an unambiguous indication whenever the
value is above the maximum positive value or below the minimum negative value of the range
to which the equipment is set.
NOTE Examples of ambiguous indications include the following, unless there is a separate unambiguous
indication of an over-range value:
a) analogue METERS with stops at the exact ends of the range;
b) digital METERS which show a low value when the true value is above the range maximum (for example
1 001,5 V displayed as 001,5 V).
Conformity is checked by inspection and by provoking an over-range condition.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 30, 2017, 01:19:43 am
For CAT II, they say less than 10kA typical.   CAT III, less than 50kA.   CAT IV, much greater than 50kA.   Wow, 50kA!!   Dave's ASTM 11A fuses are marked 30kA.  I wonder if these would be fine for a CAT IV environment. 

Hence the fuse in the (CAT IV 1000V) Amprobe HD160C:

(https://www.eevblog.com/forum/testgear/any-experience-with-an-amprobe-hd160c/?action=dlattach;attach=34509;image)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 30, 2017, 01:55:17 am
That's my guess.  The manual for the BM869s (CAT IV 1000) shows 10kA for the 400mA fuse and 20kA for the 11A.  I'm not sure what it actually has in it.  I've not had it apart since I made the repairs. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 30, 2017, 02:10:26 am
I think Cliff wiped out an interesting discussion between a YT'er and myself.  Basically this person was posting about how there was no value in these tests and how I had ran the Fluke 87V far above it's ratings.  When I asked them about it, they responded how the meter was only rated to some KVRMS.   I attempted to try and find out how they came to that conclusion and they responded with DC is the same as RMS and because I was just charging up some caps with DC then putting that across the meter, it was DC.   I think they believe it is something  like randomtronic's Mr Joules.  It made no sense that anyone with any sort of electronics or electrical aptitude would come to this conclusion.   

I was hoping they would respond but it appears YT'er or Cliff may have pulled the thread.  Not a big deal, except I now wonder how many other people think that this is what is going on. 

https://www.youtube.com/watch?v=2q1YRKyM9tU&list=PLyCxHecaZjJxLq-MldJePSMgjsBThu_PC (https://www.youtube.com/watch?v=2q1YRKyM9tU&list=PLyCxHecaZjJxLq-MldJePSMgjsBThu_PC)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on June 30, 2017, 02:34:58 am
Ignore them Joe. You've got approaching 400 thanks for your efforts and I'd bet the vast majority for fine work in this thread. Those that can't be bothered taking some time to read and watch why you embarked on this mission need not be worried about.
Drag them onto the forum and into this thread, we'll sort them out.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 30, 2017, 04:33:31 am
I have been able to help a small percentage of people understand what was going on.  If they get to be too much of a drag, I ban them.  Pretty rare that happens. 

When I was looking at that Gossen, someone had asked me about the capacitance accuracy when testing bad caps.  The were concerned with high ESR.   I don't have a supply of bad caps so I put some series resistance in-line with a good cap and tried it.  Meter did quite well.

Now that I have been playing with this pre-production 121GW, I decided to look at the capacitance measurement in more detail. I seldom use this feature and just assumed meters were not that accurate.  Much to my surprise, the meters (eight so far) I looked at all tracked fairly close.   The speed that they lock in varies a lot and so does the number of digits.   The UT61E shows off an extra digit.  Not suggesting it has any meaning but it's there.   

I can't see replacing my VNA or RLC meters just yet.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 30, 2017, 05:20:16 pm
Figured I would post the data I collected from my capacitor test.   The first two columns are my BK RLC meters. 

The Fluke 115 and HIOKI DT3252 have the lowest res of all the meters.  1nF is it.  The CEMs and UT61E have the highest res.  Surprised at how well the Fluke 101 did compared with ever other Fluke. 

Keep in mind, again most of these meters have been damaged and repaired by me.  They were not realigned and may no longer be in calibration.  The 121GW being pre-production and Dave had stated it may not have been in cal, does fairly well for being damaged twice now.  Poor thing.   And while I have not ever damaged the UT61E, that thing is far from factory original.   Was a little concerned the shield I had added to the Gossen may have hurt it but seems to have had no effect. 

Speed is all over the place and is range dependent for some meters.   For example, taking the 2200uF capacitor, shorting it, then connecting the meter to it. 

Gossen Ultra required 17.3 seconds 
CEM DD9939 required 16.1 seconds
EEVBLOG 121GW was 8.19 seconds
UT61E was 2.8 seconds

Fairly wide spread.  For me, the resistance auto-range would be far more important. 
Title: Re: Handheld meter electrical robustness testing.
Post by: iamjanco on July 01, 2017, 02:10:37 am
I have been able to help a small percentage of people understand what was going on.

Thanks, Joe. As an albeit old-timer, but noob here looking for a good, reliable logging meter that won't leak all over me nor suffer my static cling, I found the information in both this thread and your videos invaluable, as well as very well done (that's coming from someone who's fairly anal).

Feel free to up that percentage by whatever decimal place you feel appropriate. Keep up the great work! :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 01, 2017, 03:20:37 am
I have never bought the software and cable for the BM869s.  I really have no idea how it would work or if you could use your own software with it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on July 01, 2017, 04:09:15 am
I have never bought the software and cable for the BM869s.  I really have no idea how it would work or if you could use your own software with it.

I have bought the PC interface cable for this meter. The supplied software is OK and does the job. You get a projection of the meter display, a graph, and a saved copy of the history. All the standard things you would expect the software to do.

Unfortunately the interface does not create a virtual comm port, it instead uses an HID interface. Therefore to use your own software you have to create a suitable HID interface driver, which compared to programming a comm port is rather inconvenient and messy. It is something I have started to investigate but have not actually done.

I am rather disappointed that Brymen chose to design the interface cable this way. I would much rather have an RS232 type serial interface that is easy to program and universally accessible by any hardware.
Title: Re: Handheld meter electrical robustness testing.
Post by: deflicted on July 01, 2017, 12:36:16 pm
I have never bought the software and cable for the BM869s.  I really have no idea how it would work or if you could use your own software with it.

I have bought the PC interface cable for this meter. The supplied software is OK and does the job. You get a projection of the meter display, a graph, and a saved copy of the history. All the standard things you would expect the software to do.

Unfortunately the interface does not create a virtual comm port, it instead uses an HID interface. Therefore to use your own software you have to create a suitable HID interface driver, which compared to programming a comm port is rather inconvenient and messy. It is something I have started to investigate but have not actually done.

I am rather disappointed that Brymen chose to design the interface cable this way. I would much rather have an RS232 type serial interface that is easy to program and universally accessible by any hardware.

What OS? If we're talking about Linux, I might be able to help with that, since I've done similar projects at work. I don't have a BM869 to test with, but I do have the BM257, and the comm kit ordered. If the BM257 interface is similar enough, I might be able to write something that would work with the BM869. Of course, all of this is speculation at this point. I haven't read the interface spec for either meter, and I don't even have my own comm kit yet for my BM257 - it's still somewhere in Hong Kong.

If you're talking about Windows, well, then good luck. I've never written a Windows driver, so I'd have to climb that learning curve from the very beginning.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 01, 2017, 12:48:59 pm
Unfortunately the interface does not create a virtual comm port, it instead uses an HID interface.

:palm:

Thus guaranteeing incompatibility with a large percentage of the computers in the world.

(and it will only work with the others for as long as Brymen can be bothered to update the drivers, you're on your own as soon as they stop)

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 01, 2017, 01:16:50 pm
but is the HID interface in the meter, or the cable??
most meter i.c.'s just stream the lcd segments every time the display is updated.
if some smartass put a microcontroller in the cable to re-format the data, then you could build a different cable.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on July 01, 2017, 03:51:16 pm
but is the HID interface in the meter, or the cable??
It's in the cable. When you plug the cable into a USB port it creates an HID device on the host computer.

Quote
most meter i.c.'s just stream the lcd segments every time the display is updated.
Indeed, this is what the 869s does too.

Quote
if some smartass put a microcontroller in the cable to re-format the data, then you could build a different cable.
Someone did post here about creating their own cable from scratch. They reverse engineered the optical protocol at the meter and transmitted the data to the computer over a serial interface.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 01, 2017, 05:19:47 pm
I wonder if they don't have a mechanical switch in there for the leakage.   Note the mechanical breaker is still present but I suspect turn off the TRIAC when the current reaches the set point (calling that their programmable breaker).

I did not transient test the killawatt I had but I did have it apart.  Cheap, like you would expect for the price.   

Joe, just for a lark, can you put a few USB wall warts ( not the cheap ones, but ones from reputable manufacturers, because we all know how the cheap ones will fail anyhow) across your line simulator and see what it takes to kill them. My guess is that almost all of them will fail 2kV, but just how badly they do this, and how much they smoke doing so. Most will probably work fine with your test voltage, being universal input devices. You will just need a sacrificial USB voltage monitor and a resistor to draw 100mA to 500mA out of them during the test. Pretty much how they behave in transient conditions, and what a simple mains transient like a motor disconnect on the same branch circuit will affect them.

I would guess they fall under the generic case and are only required to be tested at 1KV line-to-line.   

Again, that sub 20J I test with is basically nothing.  I don't see it ever causing a meter or other device to explode or put out much for smoke.   Really what you would want to do is run these on a real combo generator if you wanted to see something more like the Fluke multimeter videos where they show the cases coming apart.  This is nothing close to what I have setup.

True, but you do have a good audience, and it will be a good thing to show that cheap and nasty really is that, even with limited energy. I think the saving grace for most products these days is the thin wire they use, which acts as an impromptu fuse when the thing fails short circuit. As the fuse is often the thing "designed" out by the cost cutters, and the wire is also "value optimised" to be as thin as possible and as low grade copper as possible this probably is the only thing keeping the fire rate down.

The transient generator will not put out the transient superimposed on the AC line.  Actually, I can't generate an AC wave with it, only the full rectified 220V.   Assuming you understood this, I am not following your thoughts of having a load and monitoring their outputs.   Could you explain this?     

I had attempted recently to try and understand a trolls comment about me applying a set of capacitors directly across the meters when I test them.  I found the comment very strange as I have shown the open circuit waveforms MANY times.  Anyone with some basic skill would understand that something is causing that decay and it's obviously not the meters.   The meters have a very high input impedance so normally all that energy is actually dissipated internal to the generators output network.  So as long as the meter does not breakdown, there will be very little that happens.   It could be a 10KJ supply and it would make no difference.  This is why you never see me run the half cycle generator unless a meter breaks down with the new generator.  Nothing will happen unless something does breakdown, then we get a little punch.  I had made a video about that generator, basically I was trying to simulate a half cycle of the CAT III 600V environment. 

The chargers on the other hand are not going to be designed for industrial use.  Not that all meters are.  I like Gossen's several comments about me running an industrial meter at 10V/m which is pretty much the industrial standard.  They test at 3 which is what my toaster is rated for.   :-DD    Anyway, these chargers would not handle a hit from that half cycle generator because again, this is trying to simulate a much higher levels than the chargers are designed for.    Also, the chargers by nature are a low impedance device.  After all we are trying to charge something with them.   So the generator may not put out enough energy to do anything.   It's like this people who post, I connected my Fluke to a 40KV supply and it lived.  Then you try to get them to explain the sources output impedance....    It's an endless supply of humor.

Point of going over all that again is that I am trying to see how you would propose that we actually run these USB supplies using this setup.  I have no problems running a few but want you to think about what it is you are asking. 
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on July 01, 2017, 07:57:20 pm
Load them with 100mA or less, just basically to get some of the less regulated ones not actually providing a 5v output, as I have seen many that will be 6V with no load and then drop with load. You DC source of 220V will be enough hopefully to provide this 0.1W of power to the DUT, and then the single pulse will easily show how they fail at providing creepage and spike resistance. Load could be basically a LED and a series resistor, and then a 68R resistor to get to around that 100mA, though I would hesitate to connect any meter you like to the secondary side, unless it will survive the full test voltage itself, or you have a big supply of those HF free meters to sacrifice on the secondary.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 02, 2017, 01:44:00 am
Load them with 100mA or less, just basically to get some of the less regulated ones not actually providing a 5v output, as I have seen many that will be 6V with no load and then drop with load. You DC source of 220V will be enough hopefully to provide this 0.1W of power to the DUT, and then the single pulse will easily show how they fail at providing creepage and spike resistance. Load could be basically a LED and a series resistor, and then a 68R resistor to get to around that 100mA, though I would hesitate to connect any meter you like to the secondary side, unless it will survive the full test voltage itself, or you have a big supply of those HF free meters to sacrifice on the secondary.

Interesting.  You think these would all run off DC?  Or have you actually tried this with a few of them?   I was thinking some of the lower end ones would not have a transformer in them.    The generator is programmable for the amount of current it can supply. 

I would have no concerns about hooking most of the remaining meters to the output to monitor.  It won't be any worse than what I have put them through!   :-DD 

Removed video reference
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2017, 03:49:34 pm
It seems like these few comments belong in this thread. 

I think it's important to also understand Joe's tests in context.
The Fluke 87V, the most trusted meter on the market, fails every single one of Joe's tests. According to Joe's tests it's one of the worst meters on the market. Yet I doubt there is a single 87V owner ever who has seen their meter die due to any ESD or pulse overload etc.

I agree.. most of the tests are a worst case scenarios (black swan events). 87v is a standard when it comes to rugged meters but has failed many of Joes tests. In fact Fluke 101  :) has passed more tests then any of the more expensive meters.

For me it's simply a matter of has a meter passed independent safety testing (UL, ETL etc). If so then it's good enough to recommend and use it on anything it's rated for.
Sure, if a meter is failing ESD testing or something that could potentially be common place, then that may be a cause for concern, but even the Fluke 87V has shown no sign of doing that in practice for the 13 years it's been released as the V series, apart from Joe's test.

So let's look at the spreadsheet.  If it's not clear, NT - Not Tested.   I had attempted to run an 87V at the same transient level that the Fluke 101 had survived to.  13KV peak, 100us FWHH and the meter failed.    I think I lost an opamp and a few clamps from that test.   Lot's of confusion about the result.  Back then I was not doing anything for the AC line, HV DC/AC or ESD.  The tests evolved after running those first set of $50 meters. 

Later I ran an 87V a second time.  Again, I did not run it on the high voltage AC/DC supply.  I also did not run the rectified AC test or try any ESD test with the grill starter.   I ran it at 1KV and it passed then switched to 1.5KV where it was damaged.   So I'm not sure what all this stuff is about it failing every single one of Joe's tests.  Again, spreadsheet and videos are on-line, you just need to look at the spreadsheet to see what was done. 

The 87V is a very old design and failed at the lowest levels of every Fluke meter I have looked at.  Maybe they learned a few tricks over the years to improve their products robustness.  Not working for Fluke, I really have no idea.  One day I may try to buy a brand new off-shore one and see if it does any better. 

I am not sure how to respond to the comment, "According to Joe's tests it's one of the worst meters on the market".  I guess that would be Dave's interpretation of the data, which based on the previous comment, I'm not sure he understood or even looked at.   Personally, my own view of the data I have collected is if your meter fails that grill starter, I don't care what it costs, those are the bottom of the barrel. 

I don't work for Fluke and have no idea about the number of returns for the 87V or the root cause of failures. 

One way to justify the level of performance is to base it off another perceived higher end product with roughly the same performance.  Fluke has really seemed to step up their own game with the newer designs I have looked at rather than holding the bar.  IMO, this is good on Fluke as a whole they are making some of the most robust meters out there today. 

Many times I have stated that for my home hobby use, I am not too concerned with the safety standards because I don't use handheld meters like these in a CATIII and up environment.   For me, passing the 61326 EMC standards is far more important.   The pre-production 121GW I have calls out the safety but not the EMC standard.   

Quote
In fact Fluke 101  :) has passed more tests then any of the more expensive meters.
Sorry, I missed responding to this one.  Again, the following is right off the spreadsheet:   

The Fluke 101 cost $48 and has been tested to 12KV 50us FWHH and to 13KV 100us FWHH and was not damaged. 
The Fluke 107 cost $117, was tested to 14KV 100us FWHH and was not damaged.
The Brymen BM235 cost $130, was tested to 12KV 50us FWHH and was not damaged.
The Fluke 115 cost $132, was tested to 12KV 50us FWHH and was not damaged.
The HIOKI DT4252 cost $150, it was tested all the way up to 14KV 50us FWHH after I added some plastic to extend the length of the barrier.  Again this meter was an oddball as the plastic had started to melt.  It was not an electrical failure like most.

Almost forgot about the most expensive handheld sitting here
The Gossen Metrawatt Metrahit Ultra Bluetooth M248B cost $850, , was tested to 12KV 50us FWHH and was not damaged.


So that's three four meters that cost more and are hanging right there with the 101.  That IS the fact!
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 03, 2017, 08:18:12 pm
Quote from: joeqsmith on June 29, 2017, 10:10:26 PM (https://www.eevblog.com/forum/index.php?topic=48998.msg1245107#msg1245107)
I think Cliff wiped out an interesting discussion between a YT'er and myself.  Basically this person was posting about how there was no value in these tests and how I had ran the Fluke 87V far above it's ratings.  When I asked them about it, they responded how the meter was only rated to some KVRMS.   I attempted to try and find out how they came to that conclusion and they responded with DC is the same as RMS and because I was just charging up some caps with DC then putting that across the meter, it was DC.   I think they believe it is something  like randomtronic's Mr Joules.  It made no sense that anyone with any sort of electronics or electrical aptitude would come to this conclusion.   

I was hoping they would respond but it appears YT'er or Cliff may have pulled the thread.  Not a big deal, except I now wonder how many other people think that this is what is going on. 

>https://www.youtube.com/watch?v=2q1YRKyM9tU&list=PLyCxHecaZjJxLq-MldJePSMgjsBThu_PCng   (https://www.youtube.com/watch?v=2q1YRKyM9tU&list=PLyCxHecaZjJxLq-MldJePSMgjsBThu_PC)

Ah.. For the record, I deleted my first post (re: corona doping in the 121GW) because I was pissed at the (nameless for now) idiot calling you a retard. Clearly, if he had any clue of the kind of work you've done on the channel, he needed his ass kicked - enough said.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2017, 08:53:16 pm
If we had saved that one comment, I would post the whole thread here, unedited.  Not to call them out for bad choice of words or for the personal attack but because I find it interesting that someone would conclude from everything I have posted that I am directly attaching charged capacitors across these meters.   :palm: 

Quote
Sure, if a meter is failing ESD testing or something that could potentially be common place, then that may be a cause for concern, but even the Fluke 87V has shown no sign of doing that in practice for the 13 years it's been released as the V series, apart from Joe's test.

But again, even Dave suggests that I ran some sort of ESD test on the 87V and it failed.  Again, nothing of the sort ever happened.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2017, 08:56:50 pm
AC and DC safety from the ARRL manual. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2017, 10:33:40 pm
The RadioShack, catalog number 22-813 

https://www.youtube.com/watch?v=r3cKTbtOdfg&feature=youtu.be (https://www.youtube.com/watch?v=r3cKTbtOdfg&feature=youtu.be)
Title: Re: Handheld meter electrical robustness testing.
Post by: mikeys on July 05, 2017, 11:02:36 am
How about testing these two rebranded Brymen pocket meters Joe? They seem to have decent input protection for the form factor. Might be a bit of a hassle for you since they don't have sockets, though. Cat III 300v rated.

http://isswww.co.uk/amprobe-pm51a-pocket-dmm-w-freq-and-capacitance (http://isswww.co.uk/amprobe-pm51a-pocket-dmm-w-freq-and-capacitance)

http://isswww.co.uk/amprobe-pm55a-automatic-precision-pocket-dmm (http://isswww.co.uk/amprobe-pm55a-automatic-precision-pocket-dmm)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on July 05, 2017, 11:37:17 am
But again, even Dave suggests that I ran some sort of ESD test on the 87V and it failed.  Again, nothing of the sort ever happened.

Ok, I stand corrected.
I could have sworn that you said this in a comment somewhere, that's what I was going off.
And above you say the 87V died at 1.5kV, but that's not on your spreadsheet?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 05, 2017, 12:08:02 pm
And above you say the 87V died at 1.5kV, but that's not on your spreadsheet?

Note that there's two Fluke 87s on the spreadsheet.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 05, 2017, 08:23:56 pm
joeqsmith, I'm curious about what kind of capacitance/series resistance is behind your transient generator?

I have used Teseq surge generators (http://www.teseq.com/product-categories/surge-generators.php) but man are they a fortune; over $26K USD plus CDN and yearly calibration was few more grand. Just super expensive, so I can see no companies spending this much on equipment for a single test.
I use lower (i.e. 12ohm vs 2ohm 61000-4-5) series resistance until I know the design has a chance.



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 06, 2017, 10:31:42 pm
joeqsmith, I'm curious about what kind of capacitance/series resistance is behind your transient generator?

I have used Teseq surge generators (http://www.teseq.com/product-categories/surge-generators.php) but man are they a fortune; over $26K USD plus CDN and yearly calibration was few more grand. Just super expensive, so I can see no companies spending this much on equipment for a single test.
I use lower (i.e. 12ohm vs 2ohm 61000-4-5) series resistance until I know the design has a chance.

Sounds like you are confusing my tests with the IEC standards.  I recommend you read the FAQ or first few pages of the thread.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 06, 2017, 10:34:40 pm
And above you say the 87V died at 1.5kV, but that's not on your spreadsheet?

Note that there's two Fluke 87s on the spreadsheet.

I've thought about putting the first round of testing on a separate page.  I can see how Dave and others could be confused.  Personally I like having it all on one page.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 07, 2017, 07:24:40 am
Sounds like you are confusing my tests with the IEC standards.  I recommend you read the FAQ or first few pages of the thread.   

I read the first 500 or so posts, over 20 pages and did not get to your latest build of the transient generator. Did not find the FAQ.
Are you ok to share ballpark rise-times and what you use as a switch element for the HV.
Like to compare with how much energy for a multimeter to jump up like some do in the videos.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 07, 2017, 11:09:44 am
I'm certainly not going to force anyone to wade through all the posts, watch the videos or read the FAQ.   
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 07, 2017, 07:27:25 pm
I've made measurements in Cat. IV and Cat. III situations and I still have my hands, most people don't know the danger there.

This whole thread is very important because it flushes out the unsafe crap on the market. Going through the 70 pages is fine, I had a few questions but understand you do not wish to share information on the transient generator.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 07, 2017, 07:41:54 pm
This whole thread is very important because it flushes out the unsafe crap on the market.

No it doesn't. This thread deals with robustness, not safety.

eg. The Fluke 87V didn't do very well here but nobody would say it's an unsafe meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 08, 2017, 07:00:59 pm
This whole thread is very important because it flushes out the unsafe crap on the market.

No it doesn't. This thread deals with robustness, not safety.

eg. The Fluke 87V didn't do very well here but nobody would say it's an unsafe meter.

I wondered about the label "robustness" because (I think) these tests are revealing multimeter failures causing arc-flash events. With mains behind such an event, the energy is lethal.
As a multimeter "weakness", I see this as a huge safety issue. Officially, yes here we are not testing to a safety standard with a pass/fail number, and these tests are to be taken as "pure entertainment" (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg698362/?topicseen#msg698362)... but the scenarios look close enough for me.

I'm measuring voltage on HV panel and it would be good to know the multimeter has some qualification to even be in that environment, never mind that my life/limb is at risk.

I think the thread has certainly flushed out meters with bogus overvoltage-withstand claims and substandard idiot protection where people could get hurt.


Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 09, 2017, 11:31:58 am
I'm measuring voltage on HV panel and it would be good to know the multimeter has some qualification to even be in that environment, never mind that my life/limb is at risk.

I think the thread has certainly flushed out meters with bogus overvoltage-withstand claims and substandard idiot protection where people could get hurt.

If anybody was measuring HV with a DT830B before they found this thread then ... they likely weren't following any other safety procedures and Darwin'll get them anyway.  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 09, 2017, 12:08:24 pm
71pages and i dont think anybody mentioned the really important bit yet - the build quality of the supplied leads/probes
Title: Re: Handheld meter electrical robustness testing.
Post by: mikeys on July 09, 2017, 12:38:10 pm
I think it's been brought up somewhere as Joe has a video on that subject on his channel. I don't recall how detailed it is though.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 09, 2017, 02:35:47 pm
71pages and i dont think anybody mentioned the really important bit yet - the build quality of the supplied leads/probes

Sure it has.

It's probably easier to find on joe's youtube channel than in the middle of all this but it's there.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 09, 2017, 04:00:19 pm
2 lead testing episodes were done a year ago (https://www.youtube.com/watch?v=fQowDZstguw (https://www.youtube.com/watch?v=fQowDZstguw) and https://www.youtube.com/watch?v=CqDxMGs_zfg (https://www.youtube.com/watch?v=CqDxMGs_zfg) ).
IMHO, it would be nice if the spreadsheet included a column with some kind of 10-point grading given to the leads/clips provided with each meter, since not everyone figures-in a set of Probe-Masters with a purchase.

Idea: Maybe 4 of the above mentioned points could relate to cable ampacity. I'd gladly donate $10 towards the purchase of a Flir to see 45 second heat video's inserted on supplied cables. AFAIK, that Labview controlled PSU could sweep 1-30 amps quick enough to avoid smoke and damage, but fast enough to see problems. These 45 sec segments Freaking guarantee you'll not find that anywhere else. But just an idea, it is..
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 09, 2017, 04:17:12 pm
i'm more interested in the insulation than the current handling.
the last 2 sets of probes i binned had the outer insulation crack at the strain-relief.
reminding me of the importance of double-insulated cable!!
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 09, 2017, 04:48:28 pm
i'm more interested in the insulation than the current handling.
the last 2 sets of probes i binned had the outer insulation crack at the strain-relief.

How exactly would you test that?
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 09, 2017, 04:54:21 pm
flex it a bit and see how it feels, try to scrape it with blunt edges - like a pcb.
ultimately, cut into one to see how many layers of insulation it has, how much actual metal is inside, and what it is - copper, aluminium, copper-coated steel etc.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 09, 2017, 10:45:58 pm
71pages and i dont think anybody mentioned the really important bit yet - the build quality of the supplied leads/probes

May 2016, Page 36, Post 897 starts the discussion if you want to read through it.    We are up almost 80 pages which does take us outside of the Dick and Jane reading level.   :-DD 

flex it a bit and see how it feels, try to scrape it with blunt edges - like a pcb.
ultimately, cut into one to see how many layers of insulation it has, how much actual metal is inside, and what it is - copper, aluminium, copper-coated steel etc.

I am not big on using feelings for a test criteria.  I also don't like tests that can't be reproduced.   Determining the materials is possible but nothing I could do at home and I doubt anyone would get much out of it anyway.  Like Fungus with the latching relays, you are certainly more than welcome to run your own test leads what ever way you see fit and post the results. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 10, 2017, 01:01:06 am
Safe meaning it has been certified to meet the IEC standards by a third party,  not that if you try and eat it, you may choke to death and therefore it's not safe.  There is a difference and why we have these standards.   But I understand your desire to troll.   This I just a bad place for it.

Point taken, but I'm sticking with the cautionary recommendation

Burial sites are stocked with many techs that may have appreciated such a 4 word 'heads up' about their decimated freshly Cal'D meter
that had all the Safety Certified confidence labels on it,
and the big price


This is my last comment and attendance at this post
I will delete the lot asap at earliest convenience

Somehow I doubt that it will be your last.  It's really not up to me to police the site, so your free to do as you wish.   And while these dead people you mention may indeed  appreciate your words of wisdom,  they may not.  We won't ever know.   What we can determine is if people who are still alieve appreciate your words of wisdom.  Time will tell.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 10, 2017, 04:38:54 pm
You can't always trust something that is stamped with a "UL" label, either because it may be faked.

What devices did you to having a fake UL mark?  With the on-line database, it's easy enough to check.   

http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/index.html?utm_source=ulcom&#038;utm_medium=web&038;utm_campaign=database (http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/index.html?utm_source=ulcom&#038;utm_medium=web&038;utm_campaign=database)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 16, 2017, 07:02:38 pm
Some time ago a friend had sent me some pictures which included their Fluke 189.  You can tell the meter was not used for high voltage high energy work.  When member EVAVA had posted about a  problem with the Brymen meters giving false readings:

https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/ (https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/)

I had asked my friend if I could borrow this meter to check it.  Well, they showed up with it this week!   They are aware of the testing I have been running and of course I promised no harm would come to their meter but I did warn them that it may come apart for a good cleaning and checkout.  I think this one has some sentimental value.   

For it's age, IMO this is a really nice general purpose meter.  I would take it over the 289 if it were still offered.  Fluke 87V, the gold standard, HA!  This was by far a better meter IMO.   

Would like to have found a new lens for it.  It's in pretty rough shape with scratches and chemical etching.  The battle scars give it character.  Some pictures showing my checkout.

Also, for what ever reason, I have been unable to get this meter to give false readings like I have seen with so many of them (basically all of them except my oldest HP bench meter).   If anyone owns the original 189, I wonder it you could confirm this. 

And no I did not spray it down with WD-40 or Windex!

Title: Re: Handheld meter electrical robustness testing.
Post by: deflicted on July 17, 2017, 12:16:48 am
For it's age, IMO this is a really nice general purpose meter.  I would take it over the 289 if it were still offered.  Fluke 87V, the gold standard, HA!  This was by far a better meter IMO.

I had the same thought recently while looking up the 189 in the multimeter spreadsheet. Someone near me has one for sale, and it's killing me that I don't have the $$$ for it, because it looks like a way better deal than a used 87V. Then again, I've already got a Brymen 257s, and even though that's a couple tiers down from either of the Flukes, it's still way more than I have any foreseeable need for.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 17, 2017, 12:21:22 am
For it's age, IMO this is a really nice general purpose meter.  I would take it over the 289 if it were still offered.  Fluke 87V, the gold standard, HA!  This was by far a better meter IMO.   
Agreed. In my opinion the only advantage of the 87 V is the smaller size and battery life (but it is AA, so you can just use low self discharge rechargeables). But the 87-series (the 87 IV aka 187 was not really part of that) is much older and the 189 was replaced by the very different (and more fiddly) 189-II/289 within ~10 years of being released. I also believe the 189 was more expensive than the 87 III. So much less will have been sold. Plus Dave never reviewed one or used one in his videos :P.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on July 17, 2017, 01:17:45 am
It always puzzles me why Fluke replaced the elegant and straightforward 189 with the inferior and overly complicated 289.

I can only assume they feared that sales of the 189 would eat into sales of the 289. Sorry Fluke, it doesn't work that way. I would buy a 189 like a shot if you offered it, but I will never buy a 289.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 17, 2017, 01:37:04 am
The 189 was discontinued because a part was discontinued. I do not know which part, but it took a while for the 189-II (289) to appear, so I imagine it required a substantial redesign. Why they radically changed the user interface I do not know. I guess they thought that the trend plotting would be a major feature.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on July 17, 2017, 02:53:58 am
There was also another series in the mix that frequently gets overlooked and that was the 863, 865 and 867b models, I'm not exactly sure on the time line for this series but I do believe that they may be the true predecessor to the 287/289 models, I have the 189 and 289 and do keep an eye out for a good 867b to complete the line up. I know member Wytnucls did have one and if anyone else here has one is there any chance of a manufacture date confirmation ?.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2017, 03:22:10 am
IMO, the graphing on the 289 is just too slow to be useful.  I like the UT181A much more than the 289 from the UI standpoint.  I don't mind the menus on the 181A (very similar to the 289).  Some things are a little cleaner IMO.  Meter is complex enough, it needs some sort of menu system.   

189 just drives very nice.  IMO, it's well thought out with just the right features I was looking for when I thought about getting a new Fluke.   If they had this meter available, I may not have the Brymen today.  That's marketing for you.  I like a few things about the Brymen but would have been very happy with ether meter.   I did not trace out the front end on the 189 to compare it with the 87V.  If I could get a brand new one, I would run it.

There was also another series in the mix that frequently gets overlooked and that was the 863, 865 and 867b models, I'm not exactly sure on the time line for this series but I do believe that they may be the true predecessor to the 287/289 models, I have the 189 and 289 and do keep an eye out for a good 867b to complete the line up. I know member Wytnucls did have one and if anyone else here has one is there any chance of a manufacture date confirmation ?.

If you don't mind, please run that test for me on your 189 and let me know if you see the same thing.   This one shows revision 015.  I find it hard to believe this meter is not plagued with the same problem but this one sure seems to look good. 
Title: Re: Handheld meter electrical robustness testing.
Post by: onlooker on July 17, 2017, 04:26:51 am
Sorry for stepping back a little here. I have just watched  the "lead testing" video. It reminds me about my long time concern and question about the aging of  the insulation material for   the leads I have.

Do we  have data to say which material is better and for how many years. What is the general consensus as to when to  throw away  the old leads (that have no visible damages)?

Were all the leads tested  in the video fairly new? It will be interesting to see some 10+  or 20+ years old leads get tested.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 17, 2017, 05:27:29 am
Silicone leads are more chemical and heat resistant, so I would expect them to last longer than PVC leads under the same circumstances.

Fluke suggest a maximum resistance of 0.5 Ohm for two leads in series (http://www.fluke.com/fluke/sgen/community/fluke-news-plus/articlecategories/safety/testing%20test%20leads) as the limit. Presumably to exceed that a significant number of strands would need to be broken.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 17, 2017, 06:18:37 am
If you don't mind, please run that test for me on your 189 and let me know if you see the same thing.   This one shows revision 015.  I find it hard to believe this meter is not plagued with the same problem but this one sure seems to look good.
I conducted the tests at 50 Hz since that is my local mains frequency and the 189 is also set to that. I could redo the tests with the 189 set to 60 Hz if that would make any difference.

In the 500 mV AC range (the lowest ACV range), it reads 500 mVRMS with 2.8 VDC offset (the maximum my function generator will do at this amplitude) without issue (within 0.1% from the value without offset, and that could easily be my function gen).

In the 50 mV DC range (manual ranging), a 45 mV DC signal with 50 Hz AC superimposed on it:
Generator mVRMS (50 Hz)F189 reading (mV DC)
5045.20
10045.19
20045.41
50045.91
100046.76
200048.61 (last digit unstable)
300048.32 (last digit unstable)
400046.00 (last digit unstable)
500037.5 (last digits unstable)
600028.7 (last digits unstable)
700023.7 (last digits unstable)

If I upranged to 500 mV with 7 VRMS AC, then it would show 51.7 mV, which could very well be correct. So I would say it seems to be performing worse than its NMRR spec of > 90 dB, which would have allowed only 0.2 mV DC change at 7 VRMS AC. Changing the frequency to 49 Hz or 51 Hz did not change the reading at all, suggesting to me that the AC signal is not reaching the ADC (which should have a much worse NMRR at 49 Hz than at 50 Hz), but affecting the analog path. If you let it autorange, it would keep switching between 500 mV and 5000 mV above 2 VRMS, so you do have to wrestle it to get it to display misleading values.

This is relying on the offset of the function gen to be correct at high amplitudes. It would probably be more accurate to AC couple the function generator and use a separate DC voltage source to add the offset. But that would have been more labor intensive.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 17, 2017, 10:54:28 am
71pages and i dont think anybody mentioned the really important bit yet - the build quality of the supplied leads/probes

May 2016, Page 36, Post 897 starts the discussion if you want to read through it.    We are up almost 80 pages which does take us outside of the Dick and Jane reading level.   :-DD 

It might be worth putting links to the principal topics in the first post.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2017, 11:49:27 am
I had just put the signal generator in series with the power supply to DC couple the two.   This meter was set to 60Hz and I was testing at 60Hz.  Your 189 in the DCmV range seems more on par with what I would normally see.  I will attempt to replicate your data to give you some idea how this one behaves.  When I looked at it the first time, it seemed pretty good but maybe I screwed something up. 


Using 60Hz with roughly 45mVDC applied and the Fluke 189 set to mV and lowest manual range.  Again, I have the DC supply in series with the AC source. 

0mVACrmsp-p   45.662mVDC
50                45.846
100              45.848
200              45.853
500              46.059
1000            46.455
2000            47.241
3000            48.595
4000            48.815
5000            49.091
6000            51.572
7000            51.647
8000            52.008
9000            52.284
10040          OL

Sadly I did not allow things to warm up but I went back and took the following after collecting the above, again with roughly 45mVDC applied:

ACrmsp-p         189
50 (30Hz)     45.865
50 (60Hz)     45.865
50 (120Hz)   45.865
50 (1KHz)     45.864
50 (2KHz)     45.865
50 (5KHz)     45.868
50 (10KHz)   45.868
50 (100KHz) 45.868
50 (500KHz) 45.869

With roughly 45mVACrms 60Hz applied,
DC offset       189
0                  45.311
1000             45.221
2000             45.214
3000             45.271
4000             45.338
5000             45.210
10000           45.214
20000           45.219   

It's strange the two 189s would behave so differently.  Again, my friend's is marked Rev 015. You would need to remove the PCB to check it.

corrected units.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2017, 11:52:14 am
71pages and i dont think anybody mentioned the really important bit yet - the build quality of the supplied leads/probes

May 2016, Page 36, Post 897 starts the discussion if you want to read through it.    We are up almost 80 pages which does take us outside of the Dick and Jane reading level.   :-DD 

It might be worth putting links to the principal topics in the first post.

If you want to take that on, you are more than welcome to do so.  I'm sure there are people who would greatly appreciate your efforts. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 17, 2017, 12:23:05 pm
It might be worth putting links to the principal topics in the first post.

If you want to take that on, you are more than welcome to do so.  I'm sure there are people who would greatly appreciate your efforts.

I don't necessarily mean sitting down and doing it but things could be added every time one comes up.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2017, 11:13:26 pm
It might be worth putting links to the principal topics in the first post.
If you want to take that on, you are more than welcome to do so.  I'm sure there are people who would greatly appreciate your efforts.
I don't necessarily mean sitting down and doing it but things could be added every time one comes up.
That true.  If you or others decide to spend time to research the thread every time someone asks a redundant question, just post a note for the reference and I could keep a running TOC in the first post.  It's not a bad idea really.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 18, 2017, 09:42:37 am
I had just put the signal generator in series with the power supply to DC couple the two.   This meter was set to 60Hz and I was testing at 60Hz.  Your 189 in the DCmV range seems more on par with what I would normally see.  I will attempt to replicate your data to give you some idea how this one behaves.  When I looked at it the first time, it seemed pretty good but maybe I screwed something up. 
I just redid the test with the following changes:
- Set the generator to 60 Hz
- Set the meter to 60 Hz (this causes DCV readings to be slightly less stable due it not rejecting mains interference anymore)
- Put a 10µF MKP capacitor in series to remove any DC offset (I measured about 5 mV DC offset with the generator set to 7VRMS at 60 Hz)
- Used a resistive passive adding network to add the DC offset from a precision power supply (see attached schematic). This halves the effective AC voltage. I report the voltage as measured at the 189 terminals with a second DMM.


AC mVRMS (60 Hz)F189 reading (mV DC)
off44.98
5044.99
10044.99
20045.64
50045.00
100045.03
200048.78
300056.14 (OL on 50 mV range)
350060.30 (OL on 50 mV range)

Now a 45 mVRMS 60 Hz signal with DC offset. I did not bother noting the last digit because it was often not very stable (meter set to 60 Hz means it is not rejecting 50 Hz interference).
DC offset (mV)F189 reading (mV AC)
045.01
100045.02
200045.02
500045.02
1000045.02
2000045.02
3000045.02
4000045.02

The DC offset has no effect, even with much higher values (up to 40 V instead of up to 2.8 V). The AC offset has the same trend as your results (but starts deviating sooner). I put the earlier result down to the DC offset not being mV-level accurate at large output amplitudes. I would have to look into the specs of the generator (HP 33120A) if this is expected behavior.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 18, 2017, 11:37:24 am
Your setup vs mine.   Same generator.   

The generator and supply were removed when measuring the zero points.   For the AC over range, the 50 ohm terminator was removed.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 18, 2017, 11:56:33 am
How much DC offset do you measure from your function gen at high amplitudes? I measured 5 mV DC (with the 189) when DC coupled at 60 Hz / 7 VRMS, and < 1 mV when AC coupled. I believe it went up with amplitude. Hence I chose to go for the AC-coupling and summing method, instead for the simpler series method.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 18, 2017, 04:39:00 pm
I can believe this.  If you look at some of the data we took, I would have considered even 20mV of error pretty good and typically I don't believe I was driving most of them this hard to get them have some major problems.   This 189 is one of the better ones I have looked at for this particular test.   

With the 50 ohm terminator, using my BM869 in the mV range and the HP344401A set to 10Vpp @ 60Hz, the Brymen shows about 6mVDC.  We are in the ballpark anyway.     


Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 19, 2017, 02:59:34 am
Just to double check, are you really reporting mVRMS for the AC voltage, and not mVp-p? Because most generators only go up to 20 Vp-p, or 7 VRMS in a high-impedance load. That makes 10 Vp-p or 3.5 VRMS with a 50 Ohm load (assuming a generator with 50 Ohm outputs). Your schematic lists a 50 Ohm load for the generator and shows voltages up to 10 VRMS, which means it could output up to ~57 Vp-p in a high impedance load.

If your voltages are actually peak to peak, then that would mean they are 2*sqrt(2) high, which would bring out results much closer together.

I am wondering if this behavior is considered within specification. The signal is not high crest factor. It appears not to meet the normal mode rejection spec. Is there some other specification that covers this?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2017, 03:48:50 am
 :-DD :-DD :-DD :-DD  Yes p-p for the constant DC test but RMS for the constant AC test.  Good catch.   

Correct original post.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 19, 2017, 04:19:32 am
I plotted your results and my second set of results for the constant DC voltage test (corrected both to RMS voltages). If you take into account that your generator may add a few mV DC offset that may account for some of the linear increase in your measurements, I would say our measurements are in agreement.

I also attached the raw data and R script I used for plotting in case anyone cares.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2017, 05:28:53 pm
Follow my videos and such you will find I make a fair number of mistakes.  Most are pretty basic. I catch most in editing and assume people will figure it out.   I could see this one causing confusion if I left it.

Have you looked at the other thread to see how this meter compares with some of the others?   If you have meters that no one ran, may be interesting to try them as well and see how they do.   I think this 189 may have been the second least effected meter of all the ones I looked at.   You would need to look at the percent and both modes.     
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on July 20, 2017, 06:38:14 am
Is this really still an open question? That other thread has not been updated for six months. and the original question of 'are there other meters that have this problem' has been answered with 'yes, several do, except for some high-end meters'. Not sure how testing more meters would contribute this is. Unless I am missing something?

To me it still seems like not meeting specifications, at least the DC mode with mains frequency AC offset. If NMRR is > 90 dB, then I expect a mains frequency signal that is ~37 dB above the DC level to have no significant influence on the readings of a 4.5 digit DMM. Changing the frequency in small steps did not seem to have any effect. But I do not see how testing more meters will answer this. You would probably need a response from the manufacturer (does Fluke still support the 189?) as to if they consider this meeting its NMRR spec.

The DC offset in ACV is not so clear, since I do not believe anyone specifies a DC rejection ratio in ACV mode. At best you could argue that it increases the crest factor beyond what is allowed. So I am not convinced that wrong ACV readings with a DC offset would be out-of-spec.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2017, 12:27:30 pm
I am not sure if there was an original question so much as OP seemed to be isolating Brymen for this problem (which was basically wrong readings without any indication of them being wrong).  Someone else attempted to replicate their test and eventually a few others started to look into its. 

For me looking at different meters continues to be an ongoing process.  I have answered my own original question that some meters are more robust than others and some very low cost meters are more robust than some high dollar ones.  The information I continue to collect may not add much to my original question, it seems I learn something from every meter I look at.  Sometimes I get complete surprises, like the Gossen Ultra with it's latching relays and high sensitivity to static.   

To what end?  I guess until I loose interest.   

I have not spent a lot of time looking at the 189 manual.  I've found most manuals pretty slim on specs.  I don't think I have ever seen NMRR spec'ed for the ones I have looked at.   

I have never attempted to contact Fluke about the 189.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2017, 12:21:56 am
After cleaning the 189 it was apparent how bad the lens was.  I looked to see if Fluke offered replacement parts. 

Shown are a before and after.  About a half hour of hand rubbing the lens with PlastX took out the majority of scratches.    Looks like it had some chemical overspray on it the etched the face and a few nicks and what almost looks like a hole punch got it.  Considering it has been in a pretty tough mechanical environment since new, it's weather well.     

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 22, 2017, 12:34:43 am
Looks great, Joe. +1 for plastic polish. For really bad scratches, wet sanding does wonders prior to the polish.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2017, 01:02:19 am
I had some paper (actually plastic, 1200 grit) but did not want to risk it.  I may try and get something a little finer then when I eventually clean up those old Fluke 97s give it a shot.  There's a lot more surface area on those.

What grit do you start and end with when you have wet sanded lenses?  Have you tried some different brands of meters?   I have though about trying to clean up my UNI-T but that plastic is very soft.   

I made an attempt to get better picture of the end result.  The dust has already collected on it.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 22, 2017, 02:15:41 am
It's been a while since I last did it. I believe I started with 1000 and worked up to 2000. Then, used clearcoat scratch remover polish with microfiber cloth. This was on a Greenlee DM820 (the old one, not 820A). Worked well for all but one really deep scratch. I didn't want to thin down the lens just for one scar.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2017, 05:23:53 pm
A few people have commented on how bad the UT181A's lens was looking.  It has some really deep scratches from working on it face down without really cleaning the mat well enough.  It seems to get scratched just taking it in and out of the case.  One of the weak points of this meter IMO. 

After a fair amount of rubbing most of the deeper scratches are gone now.   I may try and make up some protective covers for a few of these meters.

 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2017, 10:37:00 pm
Both 97s are in pretty rough shape.  Shown before and after just using the rubbing compound.  It's better but I think it's time to try something a little more aggressive.. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2017, 11:49:54 pm
Belkin iPad screen protector.  $5 for a fairly large amount of material.  Does not seem to impede the viewing and should protect the 181A's lens from further damage.   Pretty happy with the end results. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 23, 2017, 12:01:42 am
Nicely done, Joe. I see you got a score on that screen protector. I can imagine an iPad-sized sheet goes a long way for handheld DMMs.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on July 23, 2017, 12:10:07 am
I hate scratches with a passion and as you have done I put screen protectors on everything, I don't see any point spending hours buffing scratches out of a screen and then not taking additional steps or precautions to help minimise them occurring again in the future.   

Nice work as always Joe.   :-+

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 23, 2017, 02:01:35 am
it's too bad the chinese dont sell toughened glass shields, like they do for phones.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 23, 2017, 02:45:29 am
I ended up getting two of these packets.  Each packet comes with two sheets.  With one sheet, I also covered the Fluke 189, my Brymen and Dave's 121GW.  There's still a bit left.   The product is fairly easy to work with.   I give it and the PlastX both the  :-+ 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 23, 2017, 03:01:22 am
what is it, mylar?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 23, 2017, 03:28:12 am
what is it, mylar?

Sorry, I would have no way of knowing what they are using.  It's not on the package.  Maybe their website has more information about it. 

Nope:
http://www.belkin.com/us/p/P-F8W526-3/ (http://www.belkin.com/us/p/P-F8W526-3/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 25, 2017, 12:42:32 am
I am now the owner of a Fluke 189.  Don't look for it on the transient generator any time soon.   If I could buy a brand new one of these, I would run it.   

Some time back I ran an AN8002.  It held up better than a lot of meters, has more features than the Fluke 101 and is about  the same size.  The meter was badly damaged but I have ordered a brand new one.  My intent is to see if I can fit a few MOVs inside it and further increase it's robustness and maybe make a few other mods to the hardware. 

Also, I have the AN8008 on order to do a side by side comparison of the layout and run some ESD tests on.  Maybe the new ESD gun will finally damage a meter, proving that it actually does anything.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 25, 2017, 01:32:56 am
That 189 looks pretty good after the cleanup. It's worth it. I got a free multimeter with crude oil all over it, that was fun cleaning.
Used every household cleaner I have first, like IPA, Fantastic, dish soap etc. and then Comet (abrasive cleaner) and a scrub brush as the last step. Toothpaste scrub on the display window.

I haven't looked for the AN8008 PTC, it seems to be an Epcos part and DMM app notes say it affects measurements with big 10mF capacitors, so want <2k\$\Omega\$
If it turns out the PCB traces are the limiting factor, conformal coating in spots is the only fix I know of. I think the rotary switch is the bottleneck.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 25, 2017, 02:13:25 am
Wow, that 189 sure cleaned up well. I wouldn't have expected it from such a light-colored holster.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 25, 2017, 03:05:59 am
I was very much surprised when he offered it to me.  This was a dish soap and hot water job.  The meter has some marks on it from the previous two owners that I did not want to remove.  It's seen a lot of use in the automotive world.  The plastic is in fair condition.       

The AN8002's PTC's logo is similar to Epcos but I don't think it was made by them. 

Most meters I have looked at all have similar designs to protect the sensitive parts.  Really, IMO there is absolutely no reason why any meter would not be designed to handle the basic transients I put them through with my little generator.  This is IMO especially true when you start looking at $100 and up class meters. 

Now if the companies just started to design them to be connected to the outputs of MOT and car ignition coils, we would see a lot less failures... :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 25, 2017, 06:24:13 am
A very long time ago, I was at Radio Shack and a guy's wanting a refund for his Micronta analog multimeter.
It had literally exploded, the range switch blown out.
The guy had put it on amps, stuck the probes in an outlet to see if he was getting 15A like the breaker's rating  :palm:
Store manager gave him a full refund, and almost kicked me out of the store for mumbling 'WTF did he do?!'

I wondered the voltage rating on the PTC "03M" seems to be Apr (http://files.rct.ru/pdf/thermistor/ptc_mz31.pdf) MZ31 series. Epcos PTC's are all blue, B59886C012 (https://www.digikey.com/product-detail/en/epcos-tdk/B59886C0120A070/495-3894-ND/651925) is a 500V 12mA part.

Other meters use a GDT but I think these are slow to ionize, and compared to your impulse generator, MOV's maybe fast enough.
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on July 25, 2017, 12:45:08 pm
Well, did he get all 15 amps?  :-//    :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 25, 2017, 03:47:50 pm
Well, did he get all 15 amps?  :-//    :-DD

Sound to me like he did.

Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on July 25, 2017, 10:39:14 pm
In those days, cars had no airbags, no helmet to ride a bicycle, and multimeters had no fuses: Micronta_22-204A (http://ansteckend.org.uk/info/micronta/Micronta_22-204A_range_doubler_multimeter_instructions.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 25, 2017, 11:31:45 pm
All multimeters have fuses. The properly designed meters have intentionally placed ones. The rest are random. ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on July 25, 2017, 11:46:25 pm
All multimeters have fuses. The properly designed meters have intentionally placed ones. The rest are random. ;D

I regards to the major current input my Metex M-3650CR doesn't and neither did the Fluke 75 similar to the one pictured below which exploded in my left hand after a silly mistake involving three phase, it went off like a bomb, seriously.   :o ::) :P

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 25, 2017, 11:50:59 pm
Woah! Hope your hand was OK.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on July 25, 2017, 11:53:21 pm
Woah! Hope your hand paw was OK.
:phew:
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on July 25, 2017, 11:59:20 pm
They had proper thick holsters back then which managed to contain most of the blast, the selector switch and the screen acrylic went west and I ducked to the east, it's funny reading other peoples comments or theories on what may or may not happen during an event such as I described, until you have been there first hand everything else is just speculation.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 26, 2017, 12:37:40 am
They had proper thick holsters back then which managed to contain most of the blast, the selector switch and the screen acrylic went west and I ducked to the east, it's funny reading other peoples comments or theories on what may or may not happen during an event such as I described, until you have been there first hand everything else is just speculation.

So just to be clear, are you promoting cheap crap handheld meters and your favorite brand is UNI-T??   :-DD     

I wondered the voltage rating on the PTC "03M" seems to be Apr (http://files.rct.ru/pdf/thermistor/ptc_mz31.pdf) MZ31 series. Epcos PTC's are all blue, B59886C012 (https://www.digikey.com/product-detail/en/epcos-tdk/B59886C0120A070/495-3894-ND/651925) is a 500V 12mA part.

Other meters use a GDT but I think these are slow to ionize, and compared to your impulse generator, MOV's maybe fast enough.

This looks more like the logo.  I could believe the 500V rating.   They won't normally have a pulse rating on them.   A lot of companies put these piss ant PTCs in there.  They don't normally do well with my tests.   Again, really no excuse to make a meter that is not fairly robust now days.  It's not the 1980s.  Parts are readily available and the basic techniques on how to protect them is not some major PHD project.

Yes GDTs are slower than MOVs to turn on.  I made a video on switch time comparison and basic frontend protection. GDTs also latch as basically a dead short.  I assume the companies the use them do not consider the DC mode being a high risk or they have a MOV for the reset.   Very rare I see them used in handhelds. 

I looked at three meters that used GDTs.  I don't see a problem using them for the first stage of clamp assuming the designers did their job.  Of the three I tested, HIOKI, Gossen and Keysight, the Keysight was damaged at a fairly low level.   This is the reason you don't ever see a high end Keysight meter here.   Gossen has other issues. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 28, 2017, 09:12:16 pm
I just noticed you never measured the Fluke 87V continuity tester speed. I wonder if it would beat your Brymen.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on July 28, 2017, 09:17:36 pm
Speaking of continuity, as I never owned an "expensive" (I know that's relative to people and purpose) meter myself, how do the DT830's stack up with the higher quality meters?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 28, 2017, 09:55:54 pm
Speaking of continuity, as I never owned an "expensive" (I know that's relative to people and purpose) meter myself, how do the DT830's stack up with the higher quality meters?

You mean the freebies? They measure OK but they're liable to fail at any moment and I wouldn't put them within 10 yards of a mains socket.

https://www.youtube.com/watch?v=OEoazQ1zuUM (https://www.youtube.com/watch?v=OEoazQ1zuUM)

Do they even have a continuity test? Mine doesn't.

Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on July 29, 2017, 01:17:39 am
Speaking of continuity, as I never owned an "expensive" (I know that's relative to people and purpose) meter myself, how do the DT830's stack up with the higher quality meters?

You mean the freebies? They measure OK but they're liable to fail at any moment and I wouldn't put them within 10 yards of a mains socket.

https://www.youtube.com/watch?v=OEoazQ1zuUM (https://www.youtube.com/watch?v=OEoazQ1zuUM)

Do they even have a continuity test? Mine doesn't.

Somewhere they seem to be freebies, although they are the cheapest available beside that one analog meter - cost $3 or so from China ($4 for the temp measurement model 838 that comes with thermocouple). I think that 830D should have a shared diode/continuity beep test.

(http://i.imgur.com/J8W9LeK.png)

I did see that video too, you have to be careful with selecting ranges, not just with mains, and not just with this meter. The probes fail most often, and the sockets can fail.

P.S. This manual http://all-sun.com/manual/Dt830_en.pdf (http://all-sun.com/manual/Dt830_en.pdf) (I'm not sure if anyone ships that manual, just a result of a search for the models) says:

Quote
SAFETY INFORMATION
DT830 series multimeter have been designed according to IEC-1010
concerning electronic measuring instruments with a measurement category
(CAT 600V), the max. permitted transient voltage: 2500V, and pollution2.

CAT I-Measurement Category I is for measurements performed on
circuits not directly connected to mains. ( Examples are measurements
on circuits not derived from mains, and specially protected (internal)
MAINS-derived circuits. In the latter case, the transient stresses are
variable; for that reason, its necessary that the transient-withstand
-capability of equipment is made known to the user.).
Don’t use the equipment for measurement within
Measurement Categories II,III and IV.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on July 29, 2017, 03:13:28 am
Just for kicks I hooked my 121GW up to my 5kV insulation tester yesterday and it survived.
I might do some more testing to see if this can kill other meters.
Don't have a 5kV scope probe to see the waveform though, but assume there will be a small initial energy burst and then clamping down.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 29, 2017, 06:42:32 am
I did see that video too, you have to be careful with selecting ranges, not just with mains, and not just with this meter.

I don't think you watched it very carefully.

Right after the DT830 exploded he picked up a Fluke which was connected to the same power supply and held it in his hand while moving the range selector to all positions.


P.S. This manual http://all-sun.com/manual/Dt830_en.pdf (http://all-sun.com/manual/Dt830_en.pdf) (I'm not sure if anyone ships that manual, just a result of a search for the models) says:

Quote
SAFETY INFORMATION
DT830 series multimeter have been designed according to IEC-1010
concerning electronic measuring instruments with a measurement category
(CAT 600V), the max. permitted transient voltage: 2500V, and pollution2.

The IEC-1010 standard says that the meter must be safe at the maximum rated voltage with the selector in any position.

Any meter where "you have to be careful with selecting ranges" automatically fails that standard.

(ie. They're lying about the DT830 safety rating)
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on July 29, 2017, 02:47:57 pm
I did see that video too, you have to be careful with selecting ranges, not just with mains, and not just with this meter.

I don't think you watched it very carefully.

Right after the DT830 exploded he picked up a Fluke which was connected to the same power supply and held it in his hand while moving the range selector to all positions.

I meant that this isn't the only meter where you should take care to use the correct range.

Quote from: Fungus
The IEC-1010 standard says that the meter must be safe at the maximum rated voltage with the selector in any position.

Any meter where "you have to be careful with selecting ranges" automatically fails that standard.

(ie. They're lying about the DT830 safety rating)

Not a great surprise, I couldn't find after a simple search the important parts of IEC-1010, so I wouldn't know anything about the standard itself. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 29, 2017, 02:59:57 pm
Not a great surprise, I couldn't find after a simple search the important parts of IEC-1010, so I wouldn't know anything about the standard itself.

You have to pay to read it.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 29, 2017, 03:34:52 pm
I don't think you watched it very carefully.

Right after the DT830 exploded he picked up a Fluke which was connected to the same power supply and held it in his hand while moving the range selector to all positions.

natural selection may catch up with him one day.
something i'v been wondering, the standard may well say that the meter must be safe in any range/setting, but nothing about changing settings on the fly.
are the switch contacts in meters make-before-break, or break-before-make?
and what type of gap is there as the switch is rotated?

it may look clever spinning the dial with the power connected - but it's not really - it's dumb.
it's like constantly running across the street, just because your a fast runner.
sooner or later you wont be doing it again!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 29, 2017, 04:24:44 pm
Just for kicks I hooked my 121GW up to my 5kV insulation tester yesterday and it survived.
I might do some more testing to see if this can kill other meters.
Don't have a 5kV scope probe to see the waveform though, but assume there will be a small initial energy burst and then clamping down.

Hard to say much about the post.  You may have had the meter connected and in the off position for all I know.  Maybe the insulation tester was off or set to 500V.   Let's assume you actually programmed the insulation tester for 5KV and you connected between the 121GW's  V & Com inputs and checked it with the meter set to every mode and it survived.  I still have no idea what insulation tester was used.   Looking at the Hioki 3455  it looks like it has a short circuit current of 2mA or less.  It may be enough to damage the meter but I would expect the 121GW's front end to clamp that down easily, maybe. 


Added.  You are aware I had changed out the HFE part.  This is one of the weak points of the design.  If you wanted to try it with the meter set to Hz with the insulation tester putting out a positive voltage on  V/Ohm relative to GND, it may do something.  You need to somehow get the insulation tester to put out the voltage with an open, get the 5KV then discharge it across the meter.  The capacitor that AC couples the grounds together may be enough to exceed the HFE's absolute maximum supply voltage.   

A member here, Scott was playing around with electronic fly swatters and actually damaged a meter with one.   TI bought one and tried to damage the UT90A with it.  The UNI-T UT90A has had more abuse and damaged more times than any meter I have.   They flyswatter did not have enough energy to get the job done.  The UT90A's clamp would just load it down.  So I added a little external capacitance, let it charge, then discharged that into the meter.  None of this is useful data and it's not something that is recorded in my spreadsheet.     

https://www.youtube.com/watch?v=VHZ5cQPGo64 (https://www.youtube.com/watch?v=VHZ5cQPGo64)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 29, 2017, 05:02:29 pm
Saw Dave post this in the 121GW thread.  The thing that caught my attention is the Gossen Ultra Bluetooth meter.  I was aware he had the Energy and another one but this is news to me.  I wonder if Gossen supplied it as part of damage control hoping for a debunk video.  :-DD   

Personally, I would welcome seeing Dave make such a video debunking my findings with this meter.  Even just the shorted inputs, statically charged foam block and magnetic strap test with a quick pop the cover to show it looks the same as mine.   If it behaves any differently, it would be good to try and understand why. 

I have not heard any more from Gossen after they made the statement about assigning resources to look into my findings and doing a risk assessment.  Maybe a quick marketing debunk video was the best idea they could come up with?    Run it!

FYI:
https://www.youtube.com/watch?v=Wwz_fdU17aQ (https://www.youtube.com/watch?v=Wwz_fdU17aQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: evava on July 30, 2017, 06:56:09 am
Joe, according to picture I was also looking forward to temperature stability test of your new Fluke 189, do you plan to run it some time later?

And, if I may ask, could you also test $19 AN8008, when you have it?
I hope this to be better than Gossen and...  ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on July 30, 2017, 09:37:15 am
I should have ran my test at 10V and then looked at the mV as a percent change and really make those numbers look good.  But instead, I ran the same test as before.  1mV, highest sensitivity range, -20 to 60C then calculate a TC from that by looking at the change in voltage / change in temp. 

Want to know how the pre-production 121GW and Gossen M248B compare against my most stable meter, watch and find out. 

Joe, this test is completely invalid. The meter you have is not the current pre-production unit, it's a prototype that does not have the current voltage reference or divider resistors. I mentioned this in the emails to you when I sent it, so I'm not sure why you tested this.
It is most definitely not representative of the final unit.
I'd appreciate if you don't do any more further testing on this unit as it will only confuse people.
Thanks.
Title: Re: Handheld meter electrical robustness testing.
Post by: pmcouto on July 30, 2017, 10:58:32 am
No worries, Dave.

For all people following 121GW development progress it’s crystal clear that this meter is a pre-production unit, not representative of final product. We all know that final production units will have several improvements, namely better tempco voltage reference and divider resistors.

Joe’s test shows that pre-production 121GW is already one of best tested meters, beating the much higher priced Gossen. Final production units, with improved Vref and divider resistors, will surely be even better!  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 30, 2017, 12:14:07 pm
Joe, according to picture I was also looking forward to temperature stability test of your new Fluke 189, do you plan to run it some time later?

And, if I may ask, could you also test $19 AN8008, when you have it?
I hope this to be better than Gossen and...  ;)

I doubt I will do anything with the 189.  If I could buy a brand new one, I would have no problems running it through all of the tests.

For the AN8008, you want to know how temperature stable it is?   

That Gossen has been a disappointment on so many levels.  Maybe the M248B Dave has is the pinnacle of meters.  Using the data he collected, with a delta of 31.9C and 500uV spread, it's still 15.7uV/degC.  Way higher than any meter I have looked at to date.  The only worse meter I looked at was the TPI 194II and that's because the thing could not handle cold temps.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on July 30, 2017, 02:15:57 pm
@eevblog
I think Joe stated in the video that is wasn't the final production unit anyway.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 30, 2017, 08:24:54 pm
In order to avoid further confusion about the up and coming 121GW, I have removed all but the original video.  It seems having pre-production in the title and mentioning that throughout the videos and then explaining that I had even modified it, still did not mean that everyone would understand that this was not a production unit.   I assume Dave reviewed the original video of the set and gave me the thumbs up to make it public, so I plan to leave that one.   

I made an attempt to remove some of my posts detailing my findings with the 121GW as well.  I had made measurements of settling times and such for the meter which like the videos could be a source of confusion as well.   Obviously, I can't remove everything without everyone's help removing their own comments but it should help.

I am still looking forward to doing a full on review of the released meter. At that stage I will have the same meter everyone else does.  So stay tuned for that..

Also, you may have noticed that I did some additional house cleaning.  When I was looking at YT,  I was tagged several times over copyrights.  I had a video I took at the dragstrip of a friend of mind on a really old Triumph dragbike he built.   The track had music playing over the loud speaker.  Even though, it was only part of the song and it was buried by the noise, it was flagged and the audio was stripped so you could no longer hear the bikes motor.  Really sad we have come to this.   On the plus side, I don't think there was anything of great loss.  I had one video where I had worked with a guy in Australia comparing some free FEA tools with a high end product and we then modeled my one motorcycle's chassis.  We then modified the chassis to match the model.   It was the first time I ever ran a 1/4 mile in under 8 seconds.   I don't just play with meters..
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on July 30, 2017, 10:14:16 pm
I also think it would be interesting to see the AN8008's temperature stability.
And if you do get around to testing it, maybe it could be compared with AN8002?
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on July 30, 2017, 11:26:06 pm
That Gossen has been a disappointment on so many levels.  Maybe the M248B Dave has is the pinnacle of meters.

I think mine is one of the first units, I've had it for a long time and I think they sent it when it was released.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 31, 2017, 09:54:07 pm
In order to avoid further confusion about the up and coming 121GW, I have removed all but the original video.  It seems having pre-production in the title and mentioning that throughout the videos and then explaining that I had even modified it, still did not mean that everyone would understand that this was not a production unit.   I assume Dave reviewed the original video of the set and gave me the thumbs up to make it public, so I plan to leave that one.   

I made an attempt to remove some of my posts detailing my findings with the 121GW as well.  I had made measurements of settling times and such for the meter which like the videos could be a source of confusion as well.   Obviously, I can't remove everything without everyone's help removing their own comments but it should help.

I am still looking forward to doing a full on review of the released meter. At that stage I will have the same meter everyone else does.  So stay tuned for that..

Also, you may have noticed that I did some additional house cleaning.  When I was looking at YT,  I was tagged several times over copyrights.  I had a video I took at the dragstrip of a friend of mind on a really old Triumph dragbike he built.   The track had music playing over the loud speaker.  Even though, it was only part of the song and it was buried by the noise, it was flagged and the audio was stripped so you could no longer hear the bikes motor.  Really sad we have come to this.   On the plus side, I don't think there was anything of great loss.  I had one video where I had worked with a guy in Australia comparing some free FEA tools with a high end product and we then modeled my one motorcycle's chassis.  We then modified the chassis to match the model.   It was the first time I ever ran a 1/4 mile in under 8 seconds.   I don't just play with meters..
|O
In times like these, just be sure you won't be sued for libel by Fluke and Gossen due to your 87-V and MetraHit results...
Title: Re: Handheld meter electrical robustness testing.
Post by: deflicted on July 31, 2017, 10:13:26 pm
In order to avoid further confusion about the up and coming 121GW, I have removed all but the original video.  It seems having pre-production in the title and mentioning that throughout the videos and then explaining that I had even modified it, still did not mean that everyone would understand that this was not a production unit.   I assume Dave reviewed the original video of the set and gave me the thumbs up to make it public, so I plan to leave that one.   

I made an attempt to remove some of my posts detailing my findings with the 121GW as well.  I had made measurements of settling times and such for the meter which like the videos could be a source of confusion as well.   Obviously, I can't remove everything without everyone's help removing their own comments but it should help.

I am still looking forward to doing a full on review of the released meter. At that stage I will have the same meter everyone else does.  So stay tuned for that..

Also, you may have noticed that I did some additional house cleaning.  When I was looking at YT,  I was tagged several times over copyrights.  I had a video I took at the dragstrip of a friend of mind on a really old Triumph dragbike he built.   The track had music playing over the loud speaker.  Even though, it was only part of the song and it was buried by the noise, it was flagged and the audio was stripped so you could no longer hear the bikes motor.  Really sad we have come to this.   On the plus side, I don't think there was anything of great loss.  I had one video where I had worked with a guy in Australia comparing some free FEA tools with a high end product and we then modeled my one motorcycle's chassis.  We then modified the chassis to match the model.   It was the first time I ever ran a 1/4 mile in under 8 seconds.   I don't just play with meters..
|O
In times like these, just be sure you won't be sued for libel by Fluke and Gossen due to your 87-V and MetraHit results...

How is it that a video from a drag strip is flagged because there happened to be some music playing in the background, and yet there are still thousands of full albums you can listen to on YT just by Googling "<album name> full album"? Is that only true for artists who've decided that the "exposure" they get from being available on YT is a net win? Or is it just that the people uploading these videos put a new one up as soon as the old one gets taken down, forcing copyright owners to play whack-a-mole? Granted, I don't recall seeing a whole lot of Top 40 stuff available as full albums on YT, but plenty of fairly well-known bands nonetheless.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 01, 2017, 04:55:44 am
|O
In times like these, just be sure you won't be sued for libel by Fluke and Gossen due to your 87-V and MetraHit results...

I could see them going for YT first and having them close my account.  I'm not sure on what grounds other than they don't like the results.  It would be better if they spent the resources on making a better product it the goal is to do better in my tests.  I can't see screwing the results for anyone.

Had some idiot post a comment in the last video, something to the effect of me burning all my bridges and something about Dave not helping me out in the future.  I would guess I had more than 60 hours into the 121GW videos, tracking down parts, repairs, mods and such.  I don't charge anything for these videos.  I have no intentions to ever turn on ads.  I don't even have a patron or ask for money.  It's done out of pure interest on my part.  In the end, pulling the videos was the right thing to do if it really was causing confusion. 

Retrospect, I could have ran the meter to the point of not being able to repair it but I would hope that some of the information I provided Dave would help them come up with a better product. 

So to the idiot who posted that comment, let me make it clear, I could care less about burning bridges or who sends me what.  In the end, it costs me time and money.  I will continue to run the tests unbiased, collect the data and present it.  If you don't like the results, don't watch.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 01, 2017, 05:09:16 am
How is it that a video from a drag strip is flagged because there happened to be some music playing in the background, and yet there are still thousands of full albums you can listen to on YT just by Googling "<album name> full album"? Is that only true for artists who've decided that the "exposure" they get from being available on YT is a net win? Or is it just that the people uploading these videos put a new one up as soon as the old one gets taken down, forcing copyright owners to play whack-a-mole? Granted, I don't recall seeing a whole lot of Top 40 stuff available as full albums on YT, but plenty of fairly well-known bands nonetheless.

Its sad to see us reach that level of greed.  I wasn't profiting from these videos and I doubt that any were audio tracks people would rip.  In the case of my friends antique dragbike, I could not strip the music.  All I can do is remove the video or leave it without sound.   Personally, I don't mind sharing some of what I do on YT but at the same time I have wasted a fair amount of time putting the videos up only to pull them down again.   May need to rethink this whole YT thing.  Getting too old to waste too much time.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on August 01, 2017, 05:16:46 am
Its sad to see us reach that level of greed.  I wasn't profiting from these videos and I doubt that any were audio tracks people would rip.  In the case of my friends antique dragbike, I could not strip the music.  All I can do is remove the video or leave it without sound.   Personally, I don't mind sharing some of what I do on YT but at the same time I have wasted a fair amount of time putting the videos up only to pull them down again.   May need to rethink this whole YT thing.  Getting too old to waste too much time.

I don't think YouTube is the place for video sharing any more. It's too commercialized and too unfriendly to individual content creators. Maybe better to consider Vimeo or Daily Motion?
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 01, 2017, 05:18:58 am
Its sad to see us reach that level of greed.  I wasn't profiting from these videos and I doubt that any were audio tracks people would rip.  In the case of my friends antique dragbike, I could not strip the music.  All I can do is remove the video or leave it without sound.   Personally, I don't mind sharing some of what I do on YT but at the same time I have wasted a fair amount of time putting the videos up only to pull them down again.   May need to rethink this whole YT thing.  Getting too old to waste too much time.

I don't think YouTube is the place for video sharing any more. It's too commercialized and too unfriendly to individual content creators. Maybe better to consider Vimeo or Daily Motion?

In case of specialized/niche videos like these, if you make videos on those websites, would less people find them, or would it be similar?

Anyway, I'm sure it can take a lot of time and effort to run the informative tests. Thanks for doing them.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 01, 2017, 05:53:19 am
...
And, if I may ask, could you also test $19 AN8008, when you have it?
I hope this to be better than Gossen and...  ;)

I also think it would be interesting to see the AN8008's temperature stability.
And if you do get around to testing it, maybe it could be compared with AN8002?

All the meters I have looked at have drifted less than 2mV over that 80 deg C span.  Even the CEM and the UT61E were less than 600uV.  I am not sure why that Gossen was so bad.  Dave shows 500uV for a 31.9 degree change.  That's really bad from what I have seen.  Maybe I just received exceptional meters.   
 
Once I have the meters I can do some sort of comparison of the two.  Fungus was asking about the ESD so that was really my only plans for it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 01, 2017, 06:18:32 pm
|O
In times like these, just be sure you won't be sued for libel by Fluke and Gossen due to your 87-V and MetraHit results...

I could see them going for YT first and having them close my account.  I'm not sure on what grounds other than they don't like the results.  It would be better if they spent the resources on making a better product it the goal is to do better in my tests.  I can't see screwing the results for anyone.
YT is mostly concerned with media companies, thus the problem with the background music. However, it is not hard to believe this is always a possibility with absolutely everything posted on their platform. They do not really answer to any reason when a takedown notice is sent - they shoot first and ask your name later. IIRC Dave discussed this, as well as many other bloggers as the one below:
https://www.youtube.com/watch?v=oXf14eX_9Fg (https://www.youtube.com/watch?v=oXf14eX_9Fg)

 
Had some idiot post a comment in the last video, something to the effect of me burning all my bridges and something about Dave not helping me out in the future.  I would guess I had more than 60 hours into the 121GW videos, tracking down parts, repairs, mods and such.  I don't charge anything for these videos.  I have no intentions to ever turn on ads.  I don't even have a patron or ask for money.  It's done out of pure interest on my part.  In the end, pulling the videos was the right thing to do if it really was causing confusion. 

Retrospect, I could have ran the meter to the point of not being able to repair it but I would hope that some of the information I provided Dave would help them come up with a better product. 

So to the idiot who posted that comment, let me make it clear, I could care less about burning bridges or who sends me what.  In the end, it costs me time and money.  I will continue to run the tests unbiased, collect the data and present it.  If you don't like the results, don't watch.
Agreed wholeheartedly. The fanboys do not pay your bills nor help you. Of all technical folks around, I suspect that Dave would be the one that would mind the least having a fair and unbalanced review of his product. He knows nothing is perfect and, to actually put a product out of the door, you have to compromise somewhere; that or you never release anything.

Its sad to see us reach that level of greed.  I wasn't profiting from these videos and I doubt that any were audio tracks people would rip.  In the case of my friends antique dragbike, I could not strip the music.  All I can do is remove the video or leave it without sound.   Personally, I don't mind sharing some of what I do on YT but at the same time I have wasted a fair amount of time putting the videos up only to pull them down again.   May need to rethink this whole YT thing.  Getting too old to waste too much time.

I don't think YouTube is the place for video sharing any more. It's too commercialized and too unfriendly to individual content creators. Maybe better to consider Vimeo or Daily Motion?
Despite one issue here and there, I don't think YT is that bad. Also, the fact they give the space free for people with excellent content but not much traffic is an incredible feat.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 06, 2017, 06:34:17 am
Regarding robustness, now that I am waiting for a rebranded an860b+ and this video is more important for me than before:
https://www.youtube.com/watch?v=4PjmFqzlfLc (https://www.youtube.com/watch?v=4PjmFqzlfLc)
(I don't remember details so I am watching it again, although it will take a bit).

I wonder, does the larger PCB comparing to the small version make a difference? There's more space, but I don't know if it does provide better clearances.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 06, 2017, 08:09:39 am
I don't think YouTube is the place for video sharing any more. It's too commercialized and too unfriendly to individual content creators. Maybe better to consider Vimeo or Daily Motion?

Only a fool would move to another platform from Youtube. If you do then watch your existing audience drop to close to zero, and have almost zero views through search and related videos, absolutely guaranteed.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 06, 2017, 08:24:55 am
I don't think YouTube is the place for video sharing any more. It's too commercialized and too unfriendly to individual content creators. Maybe better to consider Vimeo or Daily Motion?

Only a fool would move to another platform from Youtube. If you do then watch your existing audience drop to close to zero, and have almost zero views through search and related videos, absolutely guaranteed.

One additional problem with e.g. Vimeo is that maybe you will have to pay. Not the storage limit, the limit in megabytes is possibly reasonable for a starting channel. It is up to 500 MB per week, and if I understand that right, that is possibly enough for one video per week, but I'm not sure what they consider commercial content and if electronic channels would fit there.

Quote
Businesses may not use Basic or Plus accounts to host videos. If you want to upload commercial videos, you must use Vimeo PRO or Business. Commercial content includes:

Videos promoting or representing a for-profit business or brand
Videos containing any form of advertising
Videos hosted on behalf of a business (i.e., uploaded to Vimeo and embedded on your company’s website)
Product demos and tutorials
There are exceptions, however! If you are an independent production company, author, artist, or non-profit, you may use any account type (Basic, Plus, PRO, or Business) to showcase your work.

I'm guessing basic is fine, considering the exceptions? But then, what if a channel receives a product for review (and many a do, a company sends something to review) they might have to change the plan in order to feature that video. I'm not sure.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 07, 2017, 02:41:13 am
Regarding robustness, now that I am waiting for a rebranded an860b+ and this video is more important for me than before:
...
(I don't remember details so I am watching it again, although it will take a bit).

I wonder, does the larger PCB comparing to the small version make a difference? There's more space, but I don't know if it does provide better clearances.
If the goal is to make something robust and CAT IV rated, yes having more space would make the job easier.  It does not mean that a large meter is going to be more robust than a smaller one or meet a higher standard.   The UT181A is physically a big meter and died with one strike of the stupid little grill starter.   Again, the layout needed some help.  Strange as UNI-T makes some of Danaher's products which are certified to meet the EMC standards.  The TPI194 is the same, really large but was damaged with the AC line applied.   So having all that room does not mean the designers don't have to still do their jobs. 

Look at the Brymen BM235, Fluke 101 and 107.  These are all fairly small meters and at least from my testing, some of the electrically most robust meters out there. 

The meter you referenced made all the way to 4KV.  It had some pretty bad design problems where it would give false readings.  But so can the $850 Gossen meter I have.   More money does not guarantee a good design.    I did ask Fungus to check his new one but I don't believe he ever did.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 07, 2017, 03:49:18 pm
Joe, excellent video. Interesting to see how the clamps and the thermistor are safe and sound while the meter is on fumes. Perhaps they are protecting the 3V battery? :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 08, 2017, 03:19:26 am
Joe, excellent video. Interesting to see how the clamps and the thermistor are safe and sound while the meter is on fumes. Perhaps they are protecting the 3V battery? :)
In the case of this meter along with the 8002 you are correct.   These special designers put the PTC and clamp remain safe and sound behind the rotary switch.   The switch has to take the full voltage which obviously it can't.   Most of the meters I look, if they even have a clamp, it's  located before the switch and limit the voltage to a few KV.  Sometimes they design the switch to handle this voltage, sometimes we get a light show.

Still no word on the 8008.  I do plan to run the thermal testing on these two meters (8002/8) for those of you who asked.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 08, 2017, 03:50:13 am
Joe, excellent video. Interesting to see how the clamps and the thermistor are safe and sound while the meter is on fumes. Perhaps they are protecting the 3V battery? :)
In the case of this meter along with the 8002 you are correct.   These special designers put the PTC and clamp remain safe and sound behind the rotary switch.   The switch has to take the full voltage which obviously it can't.   Most of the meters I look, if they even have a clamp, it's  located before the switch and limit the voltage to a few KV.  Sometimes they design the switch to handle this voltage, sometimes we get a light show.
Oh, I see... It may be the same special designer that did the work on a meter that had the 10A fuse on the V input (I can't recall the model/brand).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 08, 2017, 04:00:15 am
Joe, excellent video. Interesting to see how the clamps and the thermistor are safe and sound while the meter is on fumes. Perhaps they are protecting the 3V battery? :)
In the case of this meter along with the 8002 you are correct.   These special designers put the PTC and clamp remain safe and sound behind the rotary switch.   The switch has to take the full voltage which obviously it can't.   Most of the meters I look, if they even have a clamp, it's  located before the switch and limit the voltage to a few KV.  Sometimes they design the switch to handle this voltage, sometimes we get a light show.
Oh, I see... It may be the same special designer that did the work on a meter that had the 10A fuse on the V input (I can't recall the model/brand).

I really need to proof read  :-DD :-DD   I have seen a few meters with fuses in-line with the V-input.  That last RadioShack meter was like that.  But 10A??!!  Assuming they actually shared the 10A with the V, they had to switch it out.  Hard to believe that was done with the rotary switch.   They can get away with it in the mA ranges, but 10A, wow!   At least it had a fuse!  :-DD :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: evava on August 08, 2017, 06:26:45 am
I do plan to run the thermal testing on these two meters (8002/8) for those of you who asked.

And we have no objection to the 80 deg C span ! (as Dave had)  ;)

But, I would be interested in how it is with the alleged thermocouples whose influence prevails allegedly (as Dave mentioned) - could possibly someone (maybe even from Metrology section?) explain that in depth and confirm or disprove Joe's results?
Still, there is data of UT181a which does not seem to be affected by that alleged significant thermocouples influence. Could that influence be mittigated by suitable(proper) material of it's input posts in relation to the connecting conductors?

All that could be prevented (IMHO) if Joe had performed these termal testing with input posts shorted, so no different temperature and voltage potentials on the leads.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 08, 2017, 11:44:21 am
See the first few pages of this Keithley publication (http://www.tek.com/sites/tek.com/files/media/document/resources/LV_LR_e-hnbook_91113.pdf) (basically an excerpt from the excellent Keithley Low Level Measurements handbook (http://www.tek.com/sites/tek.com/files/media/document/resources/LowLevelHandbook_7Ed.pdf)) for a good discussion of thermoelectric EMFs a.k.a. the Seebeck effect.

The basics are explained in the attached figure (taken from the low level measurements handbook). If you have to dissimilar metals A and B, for example A is a piece of copper wire and B is oxidation on that copper wire, than each A-B and B-A junction generates a voltage that is approximately linear with temperature. This is how thermocouples work (hence the name thermocouple effect). As long as T1 and T2 are the same temperature, you will have two voltage sources with opposing voltages in series, so they will cancel out. But if T1 is 10 K higher than T2, then the AB junction may have a voltage that is 10 mV higher than the BA junction, resulting in a net voltage of 10 mV at the inputs of the meter. Note that these metal junctions may be inside or outside the meter.

One way to prevent this is to insure that the entire circuit is isothermal. This may not be easy if it is dissipating power somewhere. The other way is to choose your materials for low Seebeck coefficient. Copper oxide is pretty much worst case, hence why I gave that as an example. But you can't really expect your average DMM to have low thermal EMF connections. A possible location would be the leads in and out of the thermal chamber. If one of them has a shorter length outside the thermal chamber, the connector may be hotter/colder than the one with a longer length outside the chamber.

Add to this that testing near the bottom of the range exaggerates any offset errors and hides gain errors. So basically I agree with Dave that a better measurement would near full scale and not on the lowest range. Something like 1 V or 5 V might work. Sure, at 1 mV differences between the meters are larger, but are these differences meaningful and indicative of better real-world performance? Or are they just coincidence?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 08, 2017, 12:30:25 pm
I do plan to run the thermal testing on these two meters (8002/8) for those of you who asked.

And we have no objection to the 80 deg C span ! (as Dave had)  ;)

But, I would be interested in how it is with the alleged thermocouples whose influence prevails allegedly (as Dave mentioned) - could possibly someone (maybe even from Metrology section?) explain that in depth and confirm or disprove Joe's results?
Still, there is data of UT181a which does not seem to be affected by that alleged significant thermocouples influence. Could that influence be mittigated by suitable(proper) material of it's input posts in relation to the connecting conductors?

All that could be prevented (IMHO) if Joe had performed these termal testing with input posts shorted, so no different temperature and voltage potentials on the leads.

Just for reference, the following link is to the original posts:
https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/225/ (https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/225/)

I agree that the thermocouple effects are present and that to get a better picture of what the drift is doing that we need to look at several points.  There was also the concern of running them outside of their specified temperature ranges and how doing so invalidates the test.    I think the last point was they should be tested in the V range rather than the mV and near the upper limit of the range.   

Then there is the a question of how the data should be presented. One way would be to compare the overall change as a percentage of reading.  I have been showing the total difference between the min/max temperatures over the total change in temp.  The later has people questioning if the drift is linear (which I doubt) and again would point to needing more data. 

Based on one member's testing,  I have ran a few of the logging meters with a fixed temperature with the inputs shorted over an extended period.  I use a thermistor for feedback, a fairly large fan and resistors to control the temperature of a double insulated box.


I would suggest when you comment, consider that meters could range from the free harbor freight to the overprized Gossen.  Some meters may not even read into the mV let alone uVs.   Test times are a premium.  You may not want to invest a week looking at the drift of a free meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 08, 2017, 12:35:46 pm
I would suggest when you comment, consider that meters could range from the free harbor freight to the overprized Gossen.  Some meters may not even read into the mV let alone uVs.   Test times are a premium.  You may not want to invest a week looking at the drift of a free meter.

Of course. While more data is always better for comparison, for any testing that includes many meters, an automated system would be needed (something to minimize human time needed), and that would have costs associated. You're not doing this commercially, so building something too costly would be an investment that can't be returned.
Title: Re: Handheld meter electrical robustness testing.
Post by: evava on August 08, 2017, 12:37:39 pm
Thank you for your answer, Alm.

So, if I understand it well, Joe measured (on 1mV level at 80 deg C span) mainly thermocouples voltages, because half of his leads(and connections) were on (about) 25 deg C, while other half of his leads(and connections) was at changing temperature from -20 deg +60 deg.

Why no one had mentioned that before, after all everyone here watch his tests?
Why you all had been waiting on Dave and bad looking test of his 121GW, then suddenly everyone declares Joe's thermal testing for invalid?
Why did we wake up so late?
No one takes seriously testing of some UNI-T or something?
BM235 test went out well, so test was at that time good?
121GW test went out bad, so test is suddenly bad?

I hope I dont get ban for it...
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 08, 2017, 01:06:47 pm
Not necessarily. If the meter input is at 80°C, and the voltage source is at 25°C then you might have a copper-tin-copper junction at the meter (+ terminal) at 80°C, one at the voltage source at 25°C (+ terminal), another one at 25°C at the voltage source (- terminal), and another one at the meter (- terminal) at 80°C. If you do the math, then it should all cancel out. The linked Keithley document discusses this. But at these temperature differentials, it is easy to see how for example one of the jacks at the voltage source might be a few degrees warmer because it is closer to the thermal chamber. Same goes for the internal components of the meter (the input jacks may be cooler due to the cables drawing heat away).

I am not claiming that it is only the Seebeck effect and that Joe's measurements at 1 mV are worthless, but I am not convinced that the Seebeck effect is negligible either. It is somewhat suspect to me that meters that showed no difference at 1 V suddenly showed large changes at 1 mV.

As for why I did not bring this up before, because I do not regularly watch Joe's videos. I am not that interested in handheld DMMs. I only hang around for the occasional discussion of testing methods ;).

I would suggest when you comment, consider that meters could range from the free harbor freight to the overprized Gossen.  Some meters may not even read into the mV let alone uVs.   Test times are a premium.  You may not want to invest a week looking at the drift of a free meter.   
In my opinion testing at the lowest range has several problems (including Seebeck, ignoring gain errors and variation in the lowest possible range). I would suggest picking a single voltage in the 1 V - 10 V range and sticking to this. If interested, you could do multiple points in a range for a single meter at multiple temperatures to study linearity in both the voltage and temperature range, but doing that for dozens of meters is insane in my opinion. One thing I think is important because differences in the 1 V range often seemed in the order of 1 LSD is to indicate the +/- 1 LSD uncertainty. So if one meter went from 1.000 V to 1.000 V, and another went from 1.000 V to 1.001 V, then I would say the first one had 0% +/- 0.1% drift, and the second 0.1% +/- 0.1% drift.
Title: Re: Handheld meter electrical robustness testing.
Post by: mikeys on August 08, 2017, 01:25:09 pm

BM235 test went out well, so test was at that time good?
121GW test went out bad, so test is suddenly bad?

I hope I dont get ban for it...

The 121GW is a prototype unit and Dave said his intent was to send one to Joe for him to see how much it took to blow up. Testing isn't representative of the final product and though I see Joe's side of the story as he states many times that it's not a finished product and the results aren't to be taken to heart, people might make their minds up about it before it is even finished, which wouldn't be fair to Dave's efforts to make a good mid-ranged meter nor to the actual product itself.
Title: Re: Handheld meter electrical robustness testing.
Post by: evava on August 08, 2017, 03:59:44 pm
For Dave's effort - we all thank him of course.
For this forum also.
His new 121GW is going to be nice meter and good selling no doubt, no matter what happens.

I did some "temperature measurements" myself (unpublicable - in the car in the sun  ;)), and it seemed to me that (IMHO) meters have some internal (software-firmware) compensation for common temperature range (up to about 45 deg C), because meters are very stable in that range.
I consider that as "cheating".
That is why I welcome Joe's tests, they are out of this internal (software-firmware) compensation and then meter really shows what has got inside.
Therefore, (IMHO) those non-linearities.

P.S. LCD displays of the meters do not like hot+sun - do not ask how I know! Fortunately it is almost reversible.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 09, 2017, 12:33:47 am
....
121GW test went out bad, so test is suddenly bad?

I hope I dont get ban for it...

Yes, I believe some of what you wrote is true.  I often run into people trying to justify the levels that meters fail the transient testing as well.    I wouldn't be too concerned about getting dinged for asking questions.  It would be better to discuss the merits of running these tests and how best to run them, regardless of the meter being testing.  I am open for suggestions on how to run them.  Again, I have nothing to gain from it.  To me it's just data.   

It is somewhat suspect to me that meters that showed no difference at 1 V suddenly showed large changes at 1 mV.

As for why I did not bring this up before, because I do not regularly watch Joe's videos. I am not that interested in handheld DMMs. I only hang around for the occasional discussion of testing methods ;).
First, thanks for the bit of feedback. I doubt we will see too many people weighing in on this topic.     

I see a meter buff as someone who collects meters and treats them with great care.  They display them in their show cases to impress their friends perhaps changing batteries once a year and cleaning them.   :-DD   

I'm a little lost on what data are you referring to.  Which meters? 

Anyway, I don't completely disagree with what you and other have wrote.   I have always assumed the offset error would dominate from the little data I collected early on.   I can't prove it because I don't collect this data.   I agree about running them shorted for the offset.  However, we really want both gain and offset.  For gain pick a level that would not OR on any of the meters I have in their mV range.  I see no reason to run them through all of the attenuators to see how each resistor effects the gain.   I also can't see changing the range switch during the test.   Drop the temps to 0-40 to try and assume the drift is somewhat linear.  Stay with the two temperatures, so four data points total.  Use the same set of cables for all the meters on both leads, keeping everything symmetrical to minimize these errors.  We are not looking for nV errors anyway.   For presenting the data, I would just keep the raw data.   Ignoring the free HF meter, I could use 250mV as a test point for gain.  I would stay with the hour dwell times after the chamber reached the set point.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 09, 2017, 12:58:30 am
I'm a little lost on what data are you referring to.  Which meters? 
The only data I could quickly find on your channel: the data shown here (https://youtu.be/0ObW8AA42OY?t=92). Sorry if this is outdated data, I could not find it in your spreadsheet or in another easily searchable video. Now that I look at it again, actually none of the meters that perform not very well with the 1 mV tested are in your 1 V data set, so my statement about them performing much worse is not completely true. I guess the most striking difference is the BM869S which performs pretty well in the 1 V tests but mediocre in the 1 mV test.

However, we really want both gain and offset.  For gain pick a level that would not OR on any of the meters I have in their mV range.  I see no reason to run them through all of the attenuators to see how each resistor effects the gain.   I also can't see changing the range switch during the test.   Drop the temps to 0-40 to try and assume the drift is somewhat linear.  Stay with the two temperatures, so four data points total.  Use the same set of cables for all the meters on both leads, keeping everything symmetrical to minimize these errors.  We are not looking for nV errors anyway.   For presenting the data, I would just keep the raw data.   Ignoring the free HF meter, I could use 250mV as a test point for gain.  I would stay with the hour dwell times after the chamber reached the set point.
I agree with not changing the range switch during the test. I am curious why the mV range. As you say, the divider should not have much of an effect either way. I guess there could be differences in tempco between the two legs of the divider, but that does not really seems worth worrying about and is not feasible testing.

So as far as the rest of the front-end and the ADC are concerned, there is pretty much no difference between shorted inputs at the mV range or the 100 V range. Why not pick a range that is less error prone, like the range that includes 1 V? I would also guess that for most users the lowest and highest ranges are the least used, so picking a middle range makes sense. Are you deliberately testing for thermoelectric voltages inside the meters?

I guess if you wanted spectacular videos you would test at 1000 V and see how they deal with condensation :P.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 09, 2017, 05:28:45 am
For ambient temperature tests, the chinese complain about AN8002 having 100ppm/°C reference drift ala internal TL431 so that was behind the move to a dedicated external reference IC in the AN8008 ICL8069DCZR (http://www.intersil.com/content/dam/Intersil/documents/icl8/icl8069.pdf) rated 0.01%/°C

Another test to do at the same time is the cold-junction compensation, it seems to be a MCU internal diode with the same cal factors recycled for every unit. I'm not sure how well that works.

Canadian winters running a DMM even at -20°C the test leads get very hard and brittle, the LCD display fluid starts to freeze up, alkaline batteries crap out too.
I think 0°C is the lowest any DMM is good for.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 09, 2017, 05:34:54 am
The 121GW is a prototype unit and Dave said his intent was to send one to Joe for him to see how much it took to blow up.

It wasn't even for that, it was never meant to be a formal test, it was just for fun because everyone was asking for it, look at the poll in this thread! Also Joe had done one or more videos publicly asking for me to send one, so I (foolishly?) sent one before it was finished.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 09, 2017, 07:15:48 am
....
I did some "temperature measurements" myself (unpublicable - in the car in the sun  ;)), and it seemed to me that (IMHO) meters have some internal (software-firmware) compensation for common temperature range (up to about 45 deg C), because meters are very stable in that range.
I consider that as "cheating".
....
P.S. LCD displays of the meters do not like hot+sun - do not ask how I know! Fortunately it is almost reversible.

Nonlinearities in tempco come firstly from reference chip alone. And also all kinds of compensations.Bandgap reference is basically tempco compensation circuit.
Software compensation (lookup table or polynomial or whatnot) is advanced technique I doubt would be used in cheap meter..  And all of them are compensated for minimum error at normal work temperatures, at the expense of larger errors where nobody cares..  It's not cheating, it's clever engineering..

Canadian winters running a DMM even at -20°C the test leads get very hard and brittle, the LCD display fluid starts to freeze up, alkaline batteries crap out too.
I think 0°C is the lowest any DMM is good for.
This.
I don't do measurements in Siberia at -55°C. Nor I do measurements at 60°C. When temps reach 40° it becomes unsafe for people to work. I would never use my meters that I payed for at those temps, for fear of being damaged or at least being knocked out of specs.. Batteries leak, or explode (Samsung Galaxy7 ?), LCD gets damaged, plastic gets brittle or soft, so it breaks or deforms.....

It is unneeded to test outside of temp specs of device. It doesn't matter what it shows.. You can't trust it, and if you plan to do it on a regular basis it might damage your equipment. Manufacturer clearly told you , when you bought it, in specifications, that if you measure something while at 60°C meter might start showing elephants instead of Ohms, for all they care.
Unless it is a special meter specified for those temps..

I really like that Joe tries to find breaking point for voltage resilience. That is useful information. If meter gets killed by grill starter, yeah, that means your carpet can kill it.. That is something that is very likely gonna fail in service.. Also overvoltage events are unpredictable and dangerous.. So all info that shows a bit more about that is nice. And also Joe doesn't test outside of specs when testing overvoltage.. If anything, he tests at energies that are much smaller than IEC testing standards prescribe.

Of course I'm not trying to patronize anybody to tell them what to do. I like Joe's videos, and he might chose to make some that have entertainment value more so than engineering one.. That is fine.

I'm just saying that these numbers do NOT have real-world practical meaning, as some viewers seem to think.
I assure you, Joe knows that very well, too.. But he is allowed to have a bit of fun in his own private time, and that is what he does.

I just think it's a shame that he seems to have access to real thermal chamber, and is more than qualified to make real, useful thermal characterization for equipment.
So he could do it that way and finally we would be able to see some numbers manufacturers are hiding like snake is hiding legs...

But of course, it is a serious, time consuming project and I understand if he just don't have time to do it. And that is also fine with me..


Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on August 09, 2017, 07:33:03 am
I don't get why the test of Dave's meter is causing such a fuss.
All Joe did was shove some meters in a temperature chamber same as he did with the UT-61E and some others before.
He has always said that Dave's meter is NOT the final version.
Whilst the huge temperature range that Joe used in the tests isn't really the best way to assess the temp co of the meters
it does show how they survive the experience.

3DB
 
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 09, 2017, 08:12:32 am
I don't get why the test of Dave's meter is causing such a fuss.
All Joe did was shove some meters in a temperature chamber same as he did with the UT-61E and some others before.
He has always said that Dave's meter is NOT the final version.
Whilst the huge temperature range that Joe used in the tests isn't really the best way to assess the temp co of the meters
it does show how they survive the experience.

3DB

I can't speak for everyone else, but I couldn't care less about Dave's meter.. If it happens to be very good meter I'll might buy it, support it and recommend it to all my friends. If it comes out to be not so good, I will say that out loud too.
I respect Dave and his work, but it's not religion.. I don't worship anything or anybody, and Dave is not exception to that.

It's not about Dave or his meter.. If anything, Dave's meter did well compared to two other more expensive meters.

It is about test that has no technical value, to any meter out there..
It is entertainment and fine as such. Problem is that many people started to take is as  valuable info.. It is not.

Anything tested outside it's specified parameters is outside it's parameters.  It has no useful information. It's just entertainment, good fun. Nothing else.
Trying to extrapolate conclusions about quality, tempco and such, that will have practical value to anybody is at best naive...

So there you are, my explanation, for my reaction...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 09, 2017, 12:00:10 pm
The only data I could quickly find on your channel: the data shown here (https://youtu.be/0ObW8AA42OY?t=92). Sorry if this is outdated data, I could not find it in your spreadsheet or in another easily searchable video. Now that I look at it again, actually none of the meters that perform not very well with the 1 mV tested are in your 1 V data set, so my statement about them performing much worse is not completely true. I guess the most striking difference is the BM869S which performs pretty well in the 1 V tests but mediocre in the 1 mV test.

I wondered if the original data is what you were asking about.  I never made the actual spreadsheet available like I have with the transient testing.   The video you linked and a few posts are about the only places you will find it.  That data set was up to date as far as what I did with those meters. 

I agree with not changing the range switch during the test. I am curious why the mV range. As you say, the divider should not have much of an effect either way. I guess there could be differences in tempco between the two legs of the divider, but that does not really seems worth worrying about and is not feasible testing.

So as far as the rest of the front-end and the ADC are concerned, there is pretty much no difference between shorted inputs at the mV range or the 100 V range. Why not pick a range that is less error prone, like the range that includes 1 V? I would also guess that for most users the lowest and highest ranges are the least used, so picking a middle range makes sense. Are you deliberately testing for thermoelectric voltages inside the meters?

Yes I was deliberately looking for everything causing the drift down in the muck.   It appears the 8002 is marked 0-40C.  The meter that failed to run at all at -10C (TPI) is also rated for 0-40.  -10 is nothing.  I've done work many a time below these temperatures.  Granted, 10% accuracy would be fine but the meter needs to at least work.  This is partly why I pushed the temps even lower. 

I guess if you wanted spectacular videos you would test at 1000 V and see how they deal with condensation :P.

Seeing my 1000 V supplies only put out a mA or so, it shouldn't be a problem.   Maybe just run connect them to the 220AC 50A line, drop the temp to -40, then open the door and wait..  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 09, 2017, 12:02:22 pm
The 121GW is a prototype unit and Dave said his intent was to send one to Joe for him to see how much it took to blow up.
It wasn't even for that, it was never meant to be a formal test, it was just for fun because everyone was asking for it, look at the poll in this thread! Also Joe had done one or more videos publicly asking for me to send one, so I (foolishly?) sent one before it was finished.

Sorry you feel that way Dave.  I would say if anyone was the fool, it was me.  There is little I can do at this point beyond not mentioning the meter and pulling down the videos.  If you like I can remove the last one as well.   Your call.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 09, 2017, 12:16:38 pm
I'm just saying that these numbers do NOT have real-world practical meaning, as some viewers seem to think.
I assure you, Joe knows that very well, too.. But he is allowed to have a bit of fun in his own private time, and that is what he does.

I just think it's a shame that he seems to have access to real thermal chamber, and is more than qualified to make real, useful thermal characterization for equipment.
So he could do it that way and finally we would be able to see some numbers manufacturers are hiding like snake is hiding legs...

But of course, it is a serious, time consuming project and I understand if he just don't have time to do it. And that is also fine with me..

Anyone who has ever done thermal testing knows it can take a fair amount of time (weeks, months).   With the handhelds, even if I wanted to run a complex test, the data would have to be collected manually or possibly using multiple cameras inside the chamber.  A lot to invest for some cheap meters.   I'll leave that to the next person.   

So we are back to what test could be ran in the shortest time that yields the most useful information.   Again, I am open to suggestions and have posted a proposal that Alm has weighed in on.  Feel free to do the same.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 09, 2017, 01:02:45 pm
Anyone who has ever done thermal testing knows it can take a fair amount of time (weeks, months).   With the handhelds, even if I wanted to run a complex test, the data would have to be collected manually or possibly using multiple cameras inside the chamber.  A lot to invest for some cheap meters.   I'll leave that to the next person.   
I agree, am fully aware of it and I said so.. I understand you don't have time for it...

So we are back to what test could be ran in the shortest time that yields the most useful information.   Again, I am open to suggestions and have posted a proposal that Alm has weighed in on.  Feel free to do the same.   
Fair enough, so to be constructive, I agree with alm and as I stated before him, I think it should be done at volts range.. Even 1-2V is much better than millivolts (some would even say thousands times better :-DD).  Complication is with the fact that meters can have 1,2,3,4,5,6V ranges.  So full scale will be different for each one.
That can be mitigated by testing at each full range (or close to full range) and calculating and specifying tempco with percentage instead of absolute values..
So you have  meters with 4, 5 and 6V range, connect them to 4V and fire away.. Or you can test meters with same ranges together....

But simply testing at 1-2V would be enough to make it much better than testing at millivolts range..

As for testing temps, three points would be nice. 0°C,  some room temp and  40°C. 
I also can understand what you wrote about -10°C, I can see that would be interesting, if you simply have to measure something outside in winter time. So maybe that too.. That would be 4 points. And that is time consuming. Maybe 4-5 hours plus setup time..  Pretty much full day of work.
I would say you need to decide how many points you are prepared to spend time for.
And we can maybe setup some kind of voting about temps.
I have my opinion, but it is biased by my needs.. Maybe there are many more people out there that would like to see meters tested at -60°C.. What do I know what other people want...

As for automation, you might not need more than one camera, and small handheld camera is more than good enough. I have small Canon 260SX that you can manual focus, and with CHDK firmware, you can write scripts that will do time lapse and much more..

Best regards

Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 09, 2017, 01:23:40 pm
Sorry you feel that way Dave.  I would say if anyone was the fool, it was me.  There is little I can do at this point beyond not mentioning the meter and pulling down the videos.  If you like I can remove the last one as well.   Your call.

I never asked you to nor will I ask you to remove any videos. Entirely your call. I sent you an unreleased and unfinished meter and I can't and and don't want to stop you from doing what you want to do with it.
As an aside, I was surprised to see you doing more with it than I thought you wanted it for (i.e. some fun potentially blowing it up). I'm not really a follower of your videos or this thread so had no real idea about the seriousness you take all this stuff.
Sorry if you thought I was sending you a review unit, that wasn't my intention.
Just today some parts have changed again that affect the tempco and stability of the unit.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 09, 2017, 01:32:21 pm
So we are back to what test could be ran in the shortest time that yields the most useful information.   Again, I am open to suggestions and have posted a proposal that Alm has weighed in on.  Feel free to do the same.   

If you are comparing meter tempcos then just a simple delta at two temps (plus room temp) on a fixed DCV range at close to full scale.
Meter data sheet specs are typically given for room temp (23degC) +/- 5 degC. So I'd pick 10degC and 40degC as the other temps.
Room temp doesn't really take any extra time as you do it at the start of the thermal test (unless you don't work in a fairly controlled temp office environment like I do).
If you want to save extra time then just chose a temp in one direction from room temp. I'd suggest at least 20degC delta in any case. Positive or negative direction is a coin toss, doesn't really matter.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 09, 2017, 01:40:03 pm
Fair enough, so to be constructive, I agree with alm and as I stated before him, I think it should be done at volts range.. Even 1-2V is much better than millivolts (some would even say thousands times better :-DD).  Complication is with the fact that meters can have 1,2,3,4,5,6V ranges.  So full scale will be different for each one.
That can be mitigated by testing at each full range (or close to full range) and calculating and specifying tempco with percentage instead of absolute values..
So you have  meters with 4, 5 and 6V range, connect them to 4V and fire away.. Or you can test meters with same ranges together....
But simply testing at 1-2V would be enough to make it much better than testing at millivolts range..

Yes, the different counts are annoying.
1V might be the best all-round choice as it gets almost all the meters including the 10,000 count ones that usually go a little bit over.
10V reference would include another resistor in the divider chain, and that could be good or bad depending upon your viewpoint.
You don't want low ranges like 50mV that some meters have, because they will be typically using the internal chipset x10 chopper amplifier and external resistors different from the main divider chain. Although if your plan is to characterise those aspects in particular then of course it's what you'd do.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on August 09, 2017, 02:06:21 pm
Saying 60C is not a real world thing is not true, many lift motor rooms here will regularly reach that and higher in summer, as they typically are brick and concrete slab buildings on top with a lovely reflective silver concentrator of the rest of the building cooking the walls all day. Sitting with almost zero cooling aside from air vents typically closed with rodent proofing and roach proofing mesh, and with 10kW of motor heat being dissipated in the room with it as well, and all the brake, controller and shaft heat rising up into there as well. If you are unlucky you get the older ones that are basically a tin shack, walls, roof and with a tin sheet door, basically a solar oven. You go in there and it might be 60C easily, and you work fast and take regular breaks out in the up to 40C cool outside. Your meter should work there though, you will be leaving it there while you go out for the break and the look for some water to drink.

You tend to get the hotter non room temp conditions a lot more than the cold ones, though you can also be working in a cold store with it sitting at -30C as well, though you probably are really only going to be concerned with rough resistance and continuity, and if voltage is present in about the right range in these conditions.
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 09, 2017, 02:21:33 pm
I think picking a range that all meters share (e.g. the range that includes 2 V), and doing a short and a voltage close to full scale (95%) would be the best. If you present the change with shorted inputs in percent of full scale, and the change near full scale in percent of value, you would have something that is easy to compare against accuracy specs, which are typically X% of value + X% of range (or counts). It would also give you the advantage of maximizing the resolution for the gain measurement.

I do not think that using 2 V or 10 V for different meters would make any difference, assuming you have a variable precision voltage source. No worse than comparing a 2000 count meter to a 20000 count meter already does (low values may disappear in quantization noise for the 2000 count meter).

If you are comparing meter tempcos then just a simple delta at two temps (plus room temp) on a fixed DCV range at close to full scale.
Meter data sheet specs are typically given for room temp (23degC) +/- 5 degC. So I'd pick 10degC and 40degC as the other temps.
Room temp doesn't really take any extra time as you do it at the start of the thermal test (unless you don't work in a fairly controlled temp office environment like I do).
If you want to save extra time then just chose a temp in one direction from room temp. I'd suggest at least 20degC delta in any case. Positive or negative direction is a coin toss, doesn't really matter.
The question, however, is will there be anything to measure? Even for -10°C to 40°C, the deviation for several meters was down to 1 LSD (i.e. down in quantization noise), see attached frame from Joe's video that I linked to in my previous post. If you limit the temperature range even more, pretty much all meters might score < 1 LSD, which makes the test not very sensitive (mediocre meter in this regard performs the same as an excellent meter).

I would consider averaging multiple readings to increase resolution, but that would be a total pain to set up, especially in a thermal chamber, and would not be feasible for meters without computer interface (camera + OCR :P).
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 09, 2017, 04:15:42 pm
Saying 60C is not a real world thing is not true, many lift motor rooms here will regularly reach that and higher in summer, as they typically are brick and concrete slab buildings on top with a lovely reflective silver concentrator of the rest of the building cooking the walls all day. Sitting with almost zero cooling aside from air vents typically closed with rodent proofing and roach proofing mesh, and with 10kW of motor heat being dissipated in the room with it as well, and all the brake, controller and shaft heat rising up into there as well. If you are unlucky you get the older ones that are basically a tin shack, walls, roof and with a tin sheet door, basically a solar oven. You go in there and it might be 60C easily, and you work fast and take regular breaks out in the up to 40C cool outside. Your meter should work there though, you will be leaving it there while you go out for the break and the look for some water to drink.

You tend to get the hotter non room temp conditions a lot more than the cold ones, though you can also be working in a cold store with it sitting at -30C as well, though you probably are really only going to be concerned with rough resistance and continuity, and if voltage is present in about the right range in these conditions.

I understand your point. I'm from Croatia, it's 37°C in my home town now. Products I make are usually installed in metal boxes in full sun, and everything I make is specified to work to at least 65°C...

But....

Of top of my head, Fluke 87V (–20°C to + 55°C specified), Fluke 27/28 II (-15°C to +55 °C , -40 °C for up to 20 minutes) ,  Keysight U1273AX (-40°C to 55°C ),
Brymen 839 (-10°C to +50 °C), Brymen 235 (-10°C to +50 °C).......
I presume if you look further, there will be some other.  Those are specified and guaranteed to work at those temp extremes..

I wouldn't trust any meters operated outside their operating specs for serious (professional) work, no matter how well they fare in Joe's testing.
Especially if I worked on elevator motors and such installations, that are CAT III best case, and some are even CAT IV as far as overvoltage goes..

It's not that anything is wrong with his measurements, but product is not guaranteed to work out of specs.  On specific one that Joe tests, all  might even work fine and be safe, but you might go out and buy same instrument from different batch/revision... That will be assured and tested by manufacturers according their specs...But might have different behaviour outside, at the extremes....

My main handheld meters now are Brymen 869S and 525S.. But I have my trusty old Fluke 77 III  (0°C-50°C) in my carry on toolbox for when I go where it's hot...

What I'm trying to say that meters should not be tested outside specs, and then expect that because someone measured it, it is now characterised and safe to use outside manufacturer's warranty. It's not, and only manufacturer can respecify instrument for extended temperature range or whatever..

Most of the meters out there are specified for 0-40°C... For work where it's enough.

If your work requires extended operating range, you're out of luck, you're gonna have to go buy extended specification meters from known brands and pay for it...
Thinking about it, this is one of occasions, where it is much better to buy, for instance, used Fluke 87V in good shape than brand new Brymen 869..
Or maybe for motor work on line voltage, one of electrical testers like FLUKE T150 ..

Regards..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 09, 2017, 10:46:51 pm
Sorry you feel that way Dave.  I would say if anyone was the fool, it was me.  There is little I can do at this point beyond not mentioning the meter and pulling down the videos.  If you like I can remove the last one as well.   Your call.

I never asked you to nor will I ask you to remove any videos. Entirely your call. I sent you an unreleased and unfinished meter and I can't and and don't want to stop you from doing what you want to do with it.
As an aside, I was surprised to see you doing more with it than I thought you wanted it for (i.e. some fun potentially blowing it up). I'm not really a follower of your videos or this thread so had no real idea about the seriousness you take all this stuff.
Sorry if you thought I was sending you a review unit, that wasn't my intention.
Just today some parts have changed again that affect the tempco and stability of the unit.


I should have ran my test at 10V and then looked at the mV as a percent change and really make those numbers look good.  But instead, I ran the same test as before.  1mV, highest sensitivity range, -20 to 60C then calculate a TC from that by looking at the change in voltage / change in temp. 

Want to know how the pre-production 121GW and Gossen M248B compare against my most stable meter, watch and find out. 

Joe, this test is completely invalid. The meter you have is not the current pre-production unit, it's a prototype that does not have the current voltage reference or divider resistors. I mentioned this in the emails to you when I sent it, so I'm not sure why you tested this.
It is most definitely not representative of the final unit.
I'd appreciate if you don't do any more further testing on this unit as it will only confuse people.
Thanks.

Again, to avoid any confusion, I have no intent to do more with it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 09, 2017, 11:03:15 pm
The question, however, is will there be anything to measure? Even for -10°C to 40°C, the deviation for several meters was down to 1 LSD (i.e. down in quantization noise), see attached frame from Joe's video that I linked to in my previous post. If you limit the temperature range even more, pretty much all meters might score < 1 LSD, which makes the test not very sensitive (mediocre meter in this regard performs the same as an excellent meter).

And now we get to the root of the problem and why I changed the test method.  I can go back to looking at 1V and run at an even less temperature swing but from the little bit I looked at it, I don't think you will learn much from it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 09, 2017, 11:35:30 pm
I do not see away around that. You can come up with all kinds of tricks like introducing noise that you remove by averaging (Datron used this trick in some of their high-resolution bench meters), but absolutely none of that is useful if all you have is a human looking at a display. Maybe the conclusion would just be that the temperature coefficient is negligible for many 3.5 digit meters, at least as far as gain error is concerned?

I am not convinced that the larger differences in the mV range are indicative of true differences between DMMs, or if you are just magnifying noise (e.g. thermoelectric). Assuming the temperature is constant throughout the meter, the only explanations I can come up with why a full scale reading on the lowest range would have substantially more drift than on a higher range is either offset in the amplifier that is switched in for the mV ranges (is it really that interesting to focus on this detail?) or thermoelectric offset voltages between the meter and voltage source outside the thermal chamber.

It might be interesting to see how the results compare for a shorted input on the higher range. It could be that the temperature coefficient mostly affects the offset (e.g. input buffer), rather than the gain (voltage reference).

For the Fluke 189, temperature coefficient is specified as 0.05 x specified accuracy/K, which for 30K temperature difference (the tempco only applies for temperatures < 18°C or > 28°C) would +/- 30 µV for 0 V on the 50 mV range, +/- 70 µV for 50 mV on the 50 mV range, +/- 1.5 mV for 0 V on the 5 V range, and +/- 2.25 mV for 5 V range. That suggests that the error should only increase as you get closer to full scale (as makes sense). Based on that, a value close to full scale of whatever range would be optimal.

Obviously these are maximum tolerances, so real world performance will likely be much better. Is there a handheld that has the tempco specification split it in offset and gain to give an indication of expected drift?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 10, 2017, 01:10:06 am
is it really that interesting to focus on this detail?
For the normal person, I would hope not.  But we could say the same thing about the transient testing.  Is that interesting to the normal person?  I would again say no but it does seem there is a small group of us who are interested in the subject.  Maybe myself along with the other subscribers should seek help on a professional level.    :-DD
     
Quote
Maybe the conclusion would just be that the temperature coefficient is negligible for many 3.5 digit meters, at least as far as gain error is concerned?

I believe this to be the case but again my sample size is small.

With the chatter, it sounds like the temperature testing is a source of confusion.  If people want to point the finger at me or my videos, I don't mind shouldering the blame for some of it.   However, it does seem like if people are going to present thermal data for handheld meters, we should have some clear understanding about how to go about benchmarking them and what does "wow, that's pretty good" really mean.  Otherwise it seems we are just adding to the confusion. 

If I said I hooked my Fluke 101 to a 100,000VDC power supply and it lived, that would cause confusion and I could see people hooking their 101s up to their MOTs any wondering why they cooked.   This is why I try to provide as much detail as I can about the tests I run.  My tests may be flawed or deemed to have little to no value but at least you will know that my 100,000V supply was limited to 1fA.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 10, 2017, 10:42:29 am
is it really that interesting to focus on this detail?
For the normal person, I would hope not.  But we could say the same thing about the transient testing.  Is that interesting to the normal person?  I would again say no but it does seem there is a small group of us who are interested in the subject.  Maybe myself along with the other subscribers should seek help on a professional level.    :-DD
Just to be clear, that statement referred to the x10 chopper amplifier that is used only for the mV ranges. To me it seems that if you want to pick one range, it is more interesting to study the components that are used for all voltage, current and resistance measurements (ADC and voltage reference). I make no claims about being (more) sane.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 10, 2017, 10:22:42 pm
If only there was something interesting to look at with a volt signal.  Seeing a few counts of change is not much fun.  Your idea about testing them with condensation is sounding better and better...   :-DD

Maybe the two members who asked to see the 8002/8 tested over temp have an opinion on what they would like to see.  Feel free to add to the mix.

Am I the only one confused about why a meter that is checked against two higher cost units and deemed to be pretty good, would go through yet another round of mods that effect the temperature performance?   My guess is it must have been a side effect from another change and not that they are directly changing the reference circuit or attenuator network for lower drift.  It would not make sense.   
Title: Re: Handheld meter electrical robustness testing.
Post by: evava on August 11, 2017, 09:15:36 am
If only there was something interesting to look at with a volt signal.  Seeing a few counts of change is not much fun.  Your idea about testing them with condensation is sounding better and better...   :-DD

Maybe the two members who asked to see the 8002/8 tested over temp have an opinion on what they would like to see.  Feel free to add to the mix.

I think I was one of the two, I asked and still I ask you to test AN8008 - but in the original rig!
I'm not convinced that original test is completely invalid - on the contrary!
Even from previous posts is evident, and I agree with that, that test with narrower range of temperatures ( and 1V level) would probably mean "nothing to write home about".

If I were you, I would continue in that original test (-20 Deg C to +60 Deg C and 1mV), and when new 121GW is available to public, then test it too, please.
When UT181a is stable enough, let others be stable too.

It is a test, it can not be invalid (unless you compare it with manufacturer data - which you are not going to do)

Thank you in advance!
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 11, 2017, 09:29:51 am
I was probably the other (unless there was someone else too). Personally I only cared about how they compare with each other (the meters). It didn't necessarily need to be real world usage. So I'd be fine with any test that can compare meters (i.e. multiple meters being tested under the same conditions), but being a beginner to electronics, I don't have a deep enough understanding to suggest some high quality methodology. I understand that the more points measured, the more valuable the data, but it would be fun to watch either way. It's not data to draw conclusions from (e.g. how much the drift would be at specific setting at specific temperature range), but it still gives an idea on what different meters display under the same or at least very similar working conditions.

But, if most people would find that running these tests is not useful, and especially if you find it needing more time than the benefit, then I will gladly support that choice.
Title: Re: Handheld meter electrical robustness testing.
Post by: evava on August 11, 2017, 10:30:24 am
Am I the only one confused about why a meter that is checked against two higher cost units and deemed to be pretty good, would go through yet another round of mods that effect the temperature performance?   My guess is it must have been a side effect from another change and not that they are directly changing the reference circuit or attenuator network for lower drift.  It would not make sense.   
And if I understand it well, your original test (which caused all that fuss) was about "the x10 chopper amplifier that is used only for the mV ranges"  :-/O
Title: Re: Handheld meter electrical robustness testing.
Post by: alm on August 11, 2017, 11:56:59 am
If only there was something interesting to look at with a volt signal.  Seeing a few counts of change is not much fun.  Your idea about testing them with condensation is sounding better and better...   :-DD
I guess the ultimate choice is between interesting and entertaining or accurate :P.

It is a test, it can not be invalid (unless you compare it with manufacturer data - which you are not going to do)
The test may not be invalid, but is it testing the meter or the setup? Is it showing differences between meters or small differences in test setups?

Joe, do you have any idea how reproducible the 1 mV tests were? I.e. if you go back the next day and reconnect a meter, will it show the same results? If thermoelectrics indeed play a role, than I would expect a fair variation between runs due to how the cables are run and how temperature gradients across the cables are.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 11, 2017, 12:16:45 pm
And now we get to the root of the problem and why I changed the test method.  I can go back to looking at 1V and run at an even less temperature swing but from the little bit I looked at it, I don't think you will learn much from it.

On the contrary, you learn the most important thing you want to know about a meter in terms of tempco, that the meter reading basically does not change with temperature.
A null result of a test does not mean there is no value in that test, far from it.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on August 11, 2017, 12:18:26 pm
Am I the only one confused about why a meter that is checked against two higher cost units and deemed to be pretty good, would go through yet another round of mods that effect the temperature performance?

We missed something on the 50mV range.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 11, 2017, 08:04:48 pm
Am I the only one confused about why a meter that is checked against two higher cost units and deemed to be pretty good, would go through yet another round of mods that effect the temperature performance?

We missed something on the 50mV range.

Strange.  How did you find it?  Running temperature tests in the low range?  If so, how did you run them?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 11, 2017, 08:08:59 pm
Joe, do you have any idea how reproducible the 1 mV tests were? I.e. if you go back the next day and reconnect a meter, will it show the same results? If thermoelectrics indeed play a role, than I would expect a fair variation between runs due to how the cables are run and how temperature gradients across the cables are.

When I compensated that UT-61E, I made several sweeps.   Granted, I was making small changes to the meter between runs to bring it in but sure, it was stable enough setup to setup to make those measurements.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 15, 2017, 01:23:26 am
If only there was something interesting to look at with a volt signal.  Seeing a few counts of change is not much fun.  Your idea about testing them with condensation is sounding better and better...   :-DD

Maybe the two members who asked to see the 8002/8 tested over temp have an opinion on what they would like to see.  Feel free to add to the mix.

I think I was one of the two, I asked and still I ask you to test AN8008 - but in the original rig!
I'm not convinced that original test is completely invalid - on the contrary!
Even from previous posts is evident, and I agree with that, that test with narrower range of temperatures ( and 1V level) would probably mean "nothing to write home about".

If I were you, I would continue in that original test (-20 Deg C to +60 Deg C and 1mV), and when new 121GW is available to public, then test it too, please.
When UT181a is stable enough, let others be stable too.

It is a test, it can not be invalid (unless you compare it with manufacturer data - which you are not going to do)

Thank you in advance!

I was probably the other (unless there was someone else too). Personally I only cared about how they compare with each other (the meters). It didn't necessarily need to be real world usage. So I'd be fine with any test that can compare meters (i.e. multiple meters being tested under the same conditions), but being a beginner to electronics, I don't have a deep enough understanding to suggest some high quality methodology. I understand that the more points measured, the more valuable the data, but it would be fun to watch either way. It's not data to draw conclusions from (e.g. how much the drift would be at specific setting at specific temperature range), but it still gives an idea on what different meters display under the same or at least very similar working conditions.

But, if most people would find that running these tests is not useful, and especially if you find it needing more time than the benefit, then I will gladly support that choice.

I finally have both meters.  Hope to have some time this weekend to play with them.  If there are other non-destructive tests you or anyone else would like to see ran to compare the two, feel free to ask.  Otherwise, it's temperature then ESD. 

   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2017, 12:54:51 am
Just for kicks I hooked my 121GW up to my 5kV insulation tester yesterday and it survived.
I might do some more testing to see if this can kill other meters.
Don't have a 5kV scope probe to see the waveform though, but assume there will be a small initial energy burst and then clamping down.

Hard to say much about the post.  You may have had the meter connected and in the off position for all I know.  Maybe the insulation tester was off or set to 500V.   Let's assume you actually programmed the insulation tester for 5KV and you connected between the 121GW's  V & Com inputs and checked it with the meter set to every mode and it survived.  I still have no idea what insulation tester was used.   Looking at the Hioki 3455  it looks like it has a short circuit current of 2mA or less.  It may be enough to damage the meter but I would expect the 121GW's front end to clamp that down easily, maybe. 

Added.  You are aware I had changed out the HFE part.  This is one of the weak points of the design.  If you wanted to try it with the meter set to Hz with the insulation tester putting out a positive voltage on  V/Ohm relative to GND, it may do something.  You need to somehow get the insulation tester to put out the voltage with an open, get the 5KV then discharge it across the meter.  The capacitor that AC couples the grounds together may be enough to exceed the HFE's absolute maximum supply voltage.   

A member here, Scott was playing around with electronic fly swatters and actually damaged a meter with one.   TI bought one and tried to damage the UT90A with it.  The UNI-T UT90A has had more abuse and damaged more times than any meter I have.   They flyswatter did not have enough energy to get the job done.  The UT90A's clamp would just load it down.  So I added a little external capacitance, let it charge, then discharged that into the meter.  None of this is useful data and it's not something that is recorded in my spreadsheet.     

Dave,
I watched your last video and give you an A for your efforts.   Your original post makes more sense now. 

I've mentioned that I had someone post how I was directly discharging the capacitors into the meters with the generators I made.  While I have done some tests like this, the data is not recorded.   There is a coupling network that shapes the wave.  There is no magic or top secrete information to be had.  Its all explained in the IEC standards.  The wave shape is with an open circuit and the majority of the energy when I test meters is absorbed by this network, not the meters.  That is unless a meter happens to go low impedance.   This is partly why I monitor the wave shape with the scope during the tests.  Its not because I am concerned the generator looses alignment or fails, it's because I can detect when a meter is starting to breakdown.   

The big difference with the combo generators is there are two basic waveforms for surge.  The open circuit voltage and the short circuit current.  As I have explained, I am not concerned with the short circuit current waveform and limit to about 20 joules.

If you were interested in running these sort of tests for the fun of it, I would not recommend anything like my setup.  First, it will never generate the drama.  The energy levels are so far down in the mud, at best I get a few sparks emitting from a case from time to time.   My goal has never been to have them explode like some of the Fluke videos show.   If you want drama, or even to get a better idea how safe the meters are, I would recommend getting a real generator and build a small containment chamber. 

Again thanks for the video and at least putting in an effort to show what you were doing.
https://www.youtube.com/watch?v=Ru2rb7bFhag&t=25s (https://www.youtube.com/watch?v=Ru2rb7bFhag&t=25s)
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 17, 2017, 06:33:53 pm
Wait a sec, the AN8008 rotary switch wiper has less clearance than the PCB. I think that is the first breakdown point
I measured 0.6mm and the PCB has 1mm I faintly recall.
Also the voltage switch-position is furthest out and somewhat isolated, so a bit better clearance there.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 19, 2017, 02:34:46 am
The 8002 is the same way but just because they are closer does not make them instantly the breakdown point.   Without tracing the whole thing out, I would be guessing and I'm not sure it would matter.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 21, 2017, 12:47:06 am
The ANENG AN8008.  Enjoy.

https://www.youtube.com/watch?v=TSGLA9heboY (https://www.youtube.com/watch?v=TSGLA9heboY)
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 21, 2017, 01:04:50 am
The ANENG AN8008.  Enjoy.

https://www.youtube.com/watch?v=TSGLA9heboY (https://www.youtube.com/watch?v=TSGLA9heboY)

Thanks for the vid. Will check it soon.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 21, 2017, 11:48:28 am
Does that mean I owe you a meter?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 21, 2017, 12:10:42 pm
Does that mean I owe you a meter?

I think it's past the statute of limitations for meter testing. 

Hard to believe this thing can't read 10M and up and what's up with that 200MHz susceptibility?  This is the first meter I have seen that you could not even power the thing up.  Too bad they dropped the temperature input.  Personally, I would have more use for that than the signal generator.  The other things I don't like are the fuse size, the creepage/clearances around the fuses, the shared current input (may not be a problem except the clearance/creepage), putting the PTC on the backside of the switch.     Just moving the PTC would have been a step in the right direction.   That's a lot of copper.  Would like to see one of these run through the real IEC surge test for the 600V CAT III levels. 

On the plus side, they at least fixed the rectified AC line problems I saw and it does hold up to Dave's insulation tester!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 21, 2017, 02:45:26 pm
Too bad they dropped the temperature input.  Personally, I would have more use for that than the signal generator.

It reminds me of my little DT830D, it also has an output, but it's less useful being fixed at ~50 Hz (or something around that). Even with those meters, there's a model that has the more useful temperature input (DT838).
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 21, 2017, 03:27:43 pm
Does that mean I owe you a meter?

I think it's past the statute of limitations for meter testing. 

And technically, it did survive the ESD test.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on August 21, 2017, 08:15:28 pm
The ANENG AN8008.  Enjoy.

https://www.youtube.com/watch?v=TSGLA9heboY (https://www.youtube.com/watch?v=TSGLA9heboY)

Nice slow motion fireworks Joe!

Can you explain why there are two different HZ switch settings on the ZT109, one under the "VOLT" switch selection, and another in its own dedicated HZ switch position? Are they the same or do they show different results? Confused. TKS.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 22, 2017, 12:58:16 am
Does that mean I owe you a meter?
I think it's past the statute of limitations for meter testing. 
And technically, it did survive the ESD test.  :popcorn:
Nothing gets past you, well almost nothing.   After seeing the meter unable to power up with the 200MHz 3V signal applied, I was concerned it was going to have problems with the ESD but like the 8002, no problems at all.   

I was not too surprised that it was damaged at 2.5KV.  Right in the ballpark of the 8002 I looked at which was damaged at 3KV.   Spreadsheet has been updated BTW. 

Need to decide what to do with the second 8002. I was thinking to try and harden the design.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 22, 2017, 01:06:19 am
The ANENG AN8008.  Enjoy.
Nice slow motion fireworks Joe!
Can you explain why there are two different HZ switch settings on the ZT109, one under the "VOLT" switch selection, and another in its own dedicated HZ switch position? Are they the same or do they show different results? Confused. TKS.

The manual states to measure high voltage low frequency, select the DC voltage mode.  For low voltage high frequency, use the Frequency mode.   As far as what constitutes high/low voltage/frequency, I have no idea.  I could have ran tests for you had you asked a few days ago but sadly, the meter will never run again.

As far as why, vs the 8002 which only has the one setting, maybe marketing?  People like features.  Personally, I would rather have a meter with less but very solid features. 
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on August 22, 2017, 01:52:27 am
I'm aware you toasted your ZT109 for the sake of science. Mark H. (Who reviewed this meter as well) mentioned: "The AN8008/ZT109 has that auto-ranging bug with frequency in the voltage position that isn't present in the dedicated Hz position, for what that's worth."
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on August 22, 2017, 11:21:18 am
Yet another informative review/test IMO, good work joe! :-+

I kinda like these small Anengs to be honest. They have their flaws, and I think you covered them all. For electronics an AN8002/8008 combi covers 99% of my needs (and together only about $35) and I use them on my bench quite often for projects.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 23, 2017, 11:37:14 am
Grear video for the AN8008, Joe! Thanks for sharing. Nothing unexpected, of course, but at least we got an actual run on this.

One detail: be careful with these screeen polishers! They almost revealed your face to the camera, which would be dangerous as the haters can identify you and come to your house with pitchforks and torches - the 7.7% of the voters above, the Dave fanboys pissed at your 121GW tests or the clueless that think you are shoving discharged caps at inputs. :DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 24, 2017, 04:13:30 pm
Grear video for the AN8008, Joe! Thanks for sharing. Nothing unexpected, of course, but at least we got an actual run on this.

One detail: be careful with these screeen polishers! They almost revealed your face to the camera, which would be dangerous as the haters can identify you and come to your house with pitchforks and torches - the 7.7% of the voters above, the Dave fanboys pissed at your 121GW tests or the clueless that think you are shoving discharged caps at inputs. :DD

Glad you enjoyed it.   I was surprised when I could not get the meter to power up and that it could not read 10M.  For electronics hobby work, I use > 10M often.   

I've had videos up in the past of my face.  One was a full month of me not shaving for November.   It had some music in it so YT flagged it so I pulled it.

The companies may be more upset than the fans.  Then again, not much point as anyone could repeat the tests I run.   It would be better to focus on making better products if that was their goal.  I guess they could attempt to discredit me or the tests I perform but even that seems unproductive.  Fans would be better served by contacting the manufactures with what ever concerns they have.  There is really nothing I can do from my end to improve a released product.   I wonder how Gossen is making out with the Ultra.       

I've had various manufactures and distributors ask me about doing reviews now. For me the cost of the product is nothing compared with the time involved.  I have turned them all down except for when Dave offered to send the pre-production 121GW.  As Dave mentioned and I tend to agree that in hindsight, that was not such a great idea due to the confusion that it apparently caused viewers.     

Recently, UNI-T contacted me about doing a review of one of their new meters.  I was floored and asked them to spend some time looking at specific videos I have made using their products.  I'm sure someone in marketing was thinking free advertisement, which it would be but if the meter does poorly, that's a lot of bad publicity.  I can't see any benefit for a company to provide me with products unless they are VERY confident that it will do well in the tests and does not have other problems.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 24, 2017, 05:56:22 pm
Grear video for the AN8008, Joe! Thanks for sharing. Nothing unexpected, of course, but at least we got an actual run on this.

One detail: be careful with these screeen polishers! They almost revealed your face to the camera, which would be dangerous as the haters can identify you and come to your house with pitchforks and torches - the 7.7% of the voters above, the Dave fanboys pissed at your 121GW tests or the clueless that think you are shoving discharged caps at inputs. :DD

Glad you enjoyed it.   I was surprised when I could not get the meter to power up and that it could not read 10M.  For electronics hobby work, I use > 10M often.   

I've had videos up in the past of my face.  One was a full month of me not shaving for November.   It had some music in it so YT flagged it so I pulled it.

The companies may be more upset than the fans.  Then again, not much point as anyone could repeat the tests I run.   It would be better to focus on making better products if that was their goal.  I guess they could attempt to discredit me or the tests I perform but even that seems unproductive.  Fans would be better served by contacting the manufactures with what ever concerns they have.  There is really nothing I can do from my end to improve a released product.   I wonder how Gossen is making out with the Ultra.       
I agree with you and don't think they would go after you: as you always say, it is just data. If any one of them is willing to reproduce the tests then they can feel free to either create their own jig or politely ask you for the design information to faithfully re-create your setup.

That said, it may take a lot of time to improve a product after it hits the shelves - minimal changes can get past quite quickly as a "rev" update but significant ones may need recert and that on itself is a pain in the rear end. That is very hard to say if Gossen is either doing soul-searching or actually going through the motions to improve their product.

Recently, UNI-T contacted me about doing a review of one of their new meters.  I was floored and asked them to spend some time looking at specific videos I have made using their products.  I'm sure someone in marketing was thinking free advertisement, which it would be but if the meter does poorly, that's a lot of bad publicity.  I can't see any benefit for a company to provide me with products unless they are VERY confident that it will do well in the tests and does not have other problems.
I can. A company like Uni-T would benefit from an "official" review from you in a few ways:
- if all is well they get a Joe certified toughness sealTM
- if it goes bad, they get free training for their design engineers and still have a chance to review the design and present you with a tougher unit later on (wouldn't you review an UT181B or C if you could?)
- if it does ok, they can still brag about being better than an 87V


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 25, 2017, 12:15:08 am
I agree with you and don't think they would go after you: as you always say, it is just data. If any one of them is willing to reproduce the tests then they can feel free to either create their own jig or politely ask you for the design information to faithfully re-create your setup.

The easiest way would be just to use an off the shelf surge generator.  A large company could afford it, it could also be certified.  It may take longer to run the tests as you would have to be MUCH more careful.  My setup is very low energy so there is not a lot of risk running the meters in the open.  I would construct some sort of containment system.  Maybe a way to remotely turn the selector without exposing the operator.  Fun stuff for sure.  End result may have a lot more drama. 

That said, it may take a lot of time to improve a product after it hits the shelves - minimal changes can get past quite quickly as a "rev" update but significant ones may need recert and that on itself is a pain in the rear end. That is very hard to say if Gossen is either doing soul-searching or actually going through the motions to improve their product.

I agree about the time.  IMO, it would go along way for them to post that they have not forgotten and are continuing to work on it. Such a small thing may go a long way to help them.  Then again, their communication has not been a strong point. 

Recently, UNI-T contacted me about doing a review of one of their new meters.  I was floored and asked them to spend some time looking at specific videos I have made using their products.  I'm sure someone in marketing was thinking free advertisement, which it would be but if the meter does poorly, that's a lot of bad publicity.  I can't see any benefit for a company to provide me with products unless they are VERY confident that it will do well in the tests and does not have other problems.
I can. A company like Uni-T would benefit from an "official" review from you in a few ways:
- if all is well they get a Joe certified toughness sealTM
- if it goes bad, they get free training for their design engineers and still have a chance to review the design and present you with a tougher unit later on (wouldn't you review an UT181B or C if you could?)
- if it does ok, they can still brag about being better than an 87V

I doubt I carry much weight when it comes to reviews.  mjlorton, eevblog would be a better choice with their larger followings and IMO better presentation skills.   There are also very few meters that reach those upper levels.  They fail where they fail and that's what you get in the videos and spreadsheet.  There is little I can do to put a positive spin on a bad design.     

If UNI-T came out with a 181B, especially if they have it certified to the EMC standards, you know I am going to run it.  If it survived and they did not screw anything else up in the process and they address a few other small issues, that meter would be excellent for the electronic hobbyist.  My advice to them is just don't cut costs.       
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2017, 05:17:58 am
Time to decide what to do with the Kasuntest ZT102 that I bought to compare against the AN8008.  A quick search to see what other had done and I came across this review of the AN8002 which makes reference to my original video. 
http://www.markhennessy.co.uk/budget_multimeters/aneng_an8002.htm (http://www.markhennessy.co.uk/budget_multimeters/aneng_an8002.htm)

Quote
Astonishing, it had no problems going to 80MHz (yes, mega-Hz). Joe Smith's video (see below) suggests it'll go higher, but beyond that frequency the +17dBm (~1.6V) from my RF generator isn't enough for it. Joe doesn't mention the signal level used for his test.
In the first video I show the meter reading 201.5MHz.   The second meter was almost as good.   That was with the generator set to 20dBm.  Obviously, I never looked at the loading effects.

Quote
That was rather surprising, but shows that you can only predict so much from appearances. Remember, this meter has no MOVs or similar, and just a single PTC for protection.
To be clear, there is a clamp after the PTCs.  The other leg is protected by the two 5M series resistors.  The current input feeds through a two series switches and has a diode from the center node to the common.  These are the pads you see arc in Dave's video and the ones that get vaporized in mine. 

Quote
It took 3kV to damage it slightly, and ~6kV to kill the IC.
Not true.  The IC was damaged at 3KV.

Quote
And when it was hit with some seriously high energy afterwards, the case remained intact - which is really what safety is about (personal protection, not necessarily surviving electrically undamaged).
These are the kind of comments that make me cringe. I can't disagree that the OP may very well consider the half cycle simulator seriously high energy.  I have stated many times that the energy levels in these generators are quite low compared with the actual IEC standards.  I've also talked about how my goal was never to run safety tests.  The problem I see with the comment is someone not knowing any better may read this and think the meter is well protected for safety and surly it is not.   If you want to see case splitting energy levels, my channel is not the place. 

Quote
Obviously, this is for low energy electronics work only, but having said that, this meter performed really well in Joe's tests, so in reality it appears to be more rugged than you might assume.
I will agree that it is certainly more robust than many of the meters I have tested on my jig.  I imagine if the fuse were pulled (from the mA side) the meter would do worse as the switch is breaking down at a very low voltage and that circuit absorbs much of the energy.  Removing the fuse, you would increase the gap.    Again, breakdowns like this look fine on my little test setup because the energy levels I run at are so low that meters like this and some of the pocket meters actually survive to higher levels that they would with higher energy levels available.  The UNI-T UT90A is a great example of how a really bad front end design can act as a clamp and save the sensitive parts.  I have tried many times to destroy that meter and because of the limited energy level I test to, it continues to function.

Some off video comments about the AN8002/8.
Quote
The LCD is one of the best I've seen in terms of contrast and viewing angle.
Quote
This is interesting.  When I turned on my second ZT102, the first thing I noticed was how poor the LCD looked.  I also noticed that the switch did not feel near as smooth as the first one.   I swapped the LCD from the original meter which had no effect so something else has changed.  I also took apart both switches and noticed that they had changed the springs.  One set are silver, the other copper colored. I saw no other difference. 
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 26, 2017, 05:36:06 am
Time to decide what to do with the Kasuntest ZT102 that I bought to compare against the AN8008.  A quick search to see what other had done and I came across this review of the AN8002 which makes reference to my original video. 
http://www.markhennessy.co.uk/budget_multimeters/aneng_an8002.htm (http://www.markhennessy.co.uk/budget_multimeters/aneng_an8002.htm)

If it's still in good shape, maybe you might want to have it to compare with a future meter, I'm sure a new AN/ZT/DM will appear sooner or later. Might even look the same.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2017, 02:56:04 pm
Time to decide what to do with the Kasuntest ZT102 that I bought to compare against the AN8008.  A quick search to see what other had done and I came across this review of the AN8002 which makes reference to my original video. 
http://www.markhennessy.co.uk/budget_multimeters/aneng_an8002.htm (http://www.markhennessy.co.uk/budget_multimeters/aneng_an8002.htm)

If it's still in good shape, maybe you might want to have it to compare with a future meter, I'm sure a new AN/ZT/DM will appear sooner or later. Might even look the same.

It's basically brand new.  I'm thinking to get the dremel tool out and make a few changes.

Was not able to find a schematic for it.  If anyone is aware of one, please post a link.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2017, 12:50:35 am
Someone had asked about adding a MOV to the meter to improve it's robustness.   

The Kasuntest ZT102, running against the big dogs now... 
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 27, 2017, 01:12:11 am
Someone had asked about adding a MOV to the meter to improve it's robustness.   

The Kasuntest ZT102, running against the big dogs now...

The black substance helps prevent sparking over? It might be common knowledge to most here, but I'm curious about how that works. 
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on August 27, 2017, 01:32:22 am
The black substance helps prevents sparking over? It might be common knowledge to most here, but I'm curious about how that works.
Joe has previously used it in a few repairs and uses the term Corona dope.
Google finds several similar products, many of which are clear not black and if I'm not mistaken this is what Joe uses:
http://www.newark.com/gc-electronics/10-4702/corona-dope-2-oz-bottle/dp/90H9237 (http://www.newark.com/gc-electronics/10-4702/corona-dope-2-oz-bottle/dp/90H9237)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2017, 03:43:33 am
The black substance helps prevents sparking over? It might be common knowledge to most here, but I'm curious about how that works.
Joe has previously used it in a few repairs and uses the term Corona dope.
Google finds several similar products, many of which are clear not black and if I'm not mistaken this is what Joe uses:
http://www.newark.com/gc-electronics/10-4702/corona-dope-2-oz-bottle/dp/90H9237 (http://www.newark.com/gc-electronics/10-4702/corona-dope-2-oz-bottle/dp/90H9237)
Yes, that is the product I use.  Make sure you download and read the MSDS (material safety data sheet) for it before you order it.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on August 27, 2017, 05:06:39 am
The black substance helps prevents sparking over? It might be common knowledge to most here, but I'm curious about how that works.
Joe has previously used it in a few repairs and uses the term Corona dope.
Google finds several similar products, many of which are clear not black and if I'm not mistaken this is what Joe uses:
http://www.newark.com/gc-electronics/10-4702/corona-dope-2-oz-bottle/dp/90H9237 (http://www.newark.com/gc-electronics/10-4702/corona-dope-2-oz-bottle/dp/90H9237)
Yes, that is the product I use.  Make sure you download and read the MSDS (material safety data sheet) for it before you order it.

Yes, it does say hazardous item in the link - might have something to do with it. Is it safe to touch?

I was asking what it was only because I haven't seen those before (also in commercial products).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2017, 06:27:30 am
Safe is rather relative.  I can say that I have used some form of it for several decades and am still alive.  Of course, I am not afraid to use leaded solder with my bare hands as well.  It's always best to read the MSDS for any chemicals you plan to use. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2017, 06:35:07 am
My highly modified Kasuntest ZT102.

https://www.youtube.com/watch?v=OOpsHiiHtC0 (https://www.youtube.com/watch?v=OOpsHiiHtC0)
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on August 27, 2017, 05:54:59 pm
Amazing amount of custom modding. While I understand little of it, still find it entertaining. I would be heartbroken when it failed after all that time and effort, so I appreciate how far you go in your experiments!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2017, 06:51:18 pm
Amazing amount of custom modding. While I understand little of it, still find it entertaining. I would be heartbroken when it failed after all that time and effort, so I appreciate how far you go in your experiments!

Don't feel too bad.  To make all these mods, run the tests, film it, edit it was basically a day.  This was a lot less time than I spend on many of the videos I make.  The goal was not really to show how to try and improve a $15 meter but provide some education.  And while the meter dies in the end, and we know the root cause of failure.   It's not like this was the first piss ant PTC I have seen fail.  I doubt the added cost of using better parts is all that much.   I added a few pictures of the ZT102 next to the Fluke 107.  The Fluke 107 was tested at the highest levels I have generated to date.  Also note that series resistor.  They know... 
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on August 27, 2017, 07:24:37 pm
How many here or anywhere would take a full day to mod a $20 meter, just to test it to failure, for NO financial compensation? You are far too modest, and way UNDERPAID! :)
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 27, 2017, 08:33:06 pm
It's for science  :-+

P.S. I think the big WW power resistor is needed to help the PTC take the hit.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 27, 2017, 09:27:32 pm
It's for science  :-+

P.S. I think the big WW power resistor is needed to help the PTC take the hit.

Big resistor is probably carbon type, specially designed for this purpose... That is one area where carbon resistors outperform other types...
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 28, 2017, 12:05:00 am
"big resistor" seems wirewound: 3k5 WW 5% 5W 20ppm on the 87, 867, 27 etc. in series with PTC.
I think I see 1k ohm probably MOX (green body) on Asian DMM's, Brymen.

Carbon comp power-resistors are expensive and end-of-life now, drift is terrible.
Porcelain-coated nichrome is pretty good for surge power handling, but turn-turn voltage breakdown might be the limiting factor.

I never did find much short-term (<10msec) impulse data/overload specs for resistors. Did an automotive load-dump design running a resistor at >100X overload and worked with Vishay (http://www.vishay.com/resistors-fixed/high-pulse-load/) engineers on it. It was hell because the SMT WW resistor's thermal properties, wire melting point were modeled.

A 6kV impulse, couple 1.5kV (clamping) MOV's, 1.5kohm PTC and 3.5kohm 'big resistor", that's only 0.6A instantaneous or 1.3kW for it, and 0.54kW for the PTC. Hmmm.
If my numbers are reasonable, 250X overload but really brief but really big...

Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 28, 2017, 07:50:06 am

Carbon comp power-resistors are expensive and end-of-life now, drift is terrible.


They are non inductive, and spreading current and voltage field uniformly across... Very good, very robust.
Drift and tolerance is non important with the way they are connected into circuit..

I agree, ceramic composition solid body ones are stealing the show with even better characteristics...

There are thick film and wirewound resistors with enhanced surge ratings, but they have lower max overvoltage, good energy ratings though....
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 29, 2017, 01:13:03 am
How many here or anywhere would take a full day to mod a $20 meter, just to test it to failure, for NO financial compensation? You are far too modest, and way UNDERPAID! :)

The problem with taking money or even meters is it could be viewed as a conflict of interest.   Dave presented a rare opportunity which was a little hard to pass up and I am sure there were people out there thinking I was in Dave's pocket, all the while Dave cringing as I continued to push his meter.  :-DD 

I try and repeat the same set of tests, collect the data and let you see it for free.  Fairly cut and dry. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 29, 2017, 02:02:49 am
It's for science  :-+

P.S. I think the big WW power resistor is needed to help the PTC take the hit.


Shown are the Fluke 115 which was tested up to 12KV 50us FWHH pulse with no damage), the HIOKI DT4252 (which started to arc around a plastic spacer at 10KV but with some added plastic, made it to 14KV 50us FWHH with no further damage), and while the Gossen M248B has lots of problem the one thing it has going for it is that's it very robust, surviving 12KV 50us FWHH).   I've shown you the Fluke 107.  Again, I've never had the 101 apart.  Everyone has seen the Brymen BM235.  These are all CAT III 600V and up rated and certified for both EMC and safety.  This is true for the BM235 as well.  BIG PTC, series resistor.  It's not back magic and it's not what you find on cheap meters.

Meters like the UT61E need a little help.   

Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 29, 2017, 04:46:35 am
The Gossen's gas tubes are fast enough?

The Hioki PCB DT4252 layout- a 1,000V fuse with tiny spacing between the trace and clip.
I'd expect an arc there after the fuse clears. Sigh. Engineer's screwup telling PCB CAD guy that both sides of a fuse are at the same potential. Not after it blows...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 29, 2017, 11:12:39 am
The Gossen's gas tubes are fast enough?
Three meters I have ran used GDTs.  Both this Gossen and HIOKI survived.  There was also a Keysight meter that failed at 5KV.  Because the Keysight failed with the small generator, it was a candidate for the half cycle generator as well.  Not a great test but the added energy gives you some idea how other areas in the meter may fair once we have a breakdown.   

The Hioki PCB DT4252 layout- a 1,000V fuse with tiny spacing between the trace and clip.
I'd expect an arc there after the fuse clears. Sigh. Engineer's screwup telling PCB CAD guy that both sides of a fuse are at the same potential. Not after it blows...
There is no need to guess about the HIKOI.  If you look on page 31 of this thread, we spent some time going over it.   

EN 61010-1:2001
Quote
Fuse holders with fuses intended to be replaceable by an OPERATOR shall not permit access to parts which are HAZARDOUS LIVE during fuse replacement.

EN 61010-2-033:2012
Quote
101.3.2 Protection by a certified overcurrent protection device
If the protection device is a fuse, it is replaced with an open-circuited fuse. ....
A voltage of two times the highest RATED voltage for any TERMINAL is applied to the TERMINALS of the overcurrent-protected measuring circuit for 1 min. The source of the test voltage shall be capable of delivering 500 VA. During and after the test, no damage to the equipment shall occur.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 29, 2017, 11:24:21 am
There is no need to guess about the HIKOI.  If you look on page 31 of this thread, we spent some time going over it.   

Link!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 29, 2017, 11:46:11 am
There is no need to guess about the HIKOI.  If you look on page 31 of this thread, we spent some time going over it.   

Link!
Screwdriver drop test!!! :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 29, 2017, 12:41:27 pm
I though you were going to add links to specific meters on the first page as they came up.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 29, 2017, 11:14:01 pm
I thought you were going to do a drop test on some meters.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: CustomEngineerer on August 29, 2017, 11:21:30 pm
There is no need to guess about the HIKOI.  If you look on page 31 of this thread, we spent some time going over it.   

Link!
Screwdriver drop test!!! :popcorn:

That made me laugh a lot more than it should have.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 29, 2017, 11:38:42 pm
UL 61010 certifiers told me spacings must be met around the entire fuse; (not just the end-bells or clips). Why :-//  the mid-section is ceramic.
Their answer:
Because you never know exactly where inside a fuse the link has melted i.e middle, left, right- regulatory consider the entire body of the fuse energized to hazardous live, and carbonized (=conductive).

So I had to do placement and PCB layout that leaves a large island around the entire fuse. If parts are too close, you see heatshrink covers used.

It's too bad a 5x20mm fuse could not be developed with a (DMM) 1kV high-interrupt rating. These DMM fuses are pretty huge.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 30, 2017, 11:11:28 am
UL 61010 certifiers told me spacings must be met around the entire fuse; (not just the end-bells or clips). Why :-//  the mid-section is ceramic.
Their answer:
Because you never know exactly where inside a fuse the link has melted i.e middle, left, right- regulatory consider the entire body of the fuse energized to hazardous live, and carbonized (=conductive).

I assume you are referring to a hand-held meter. 
EN 61010-2-033:2012
Quote
Additionally, spacings surrounding the overcurrent protection device in the equipment and following the protection device in the measuring circuit shall be sufficiently large to prevent arcing after the protection device opens.
This is under 101.3.2 and requires the same test as above.  This assumes you are using a certified fuse. 

So I had to do placement and PCB layout that leaves a large island around the entire fuse. If parts are too close, you see heatshrink covers used.

It's too bad a 5x20mm fuse could not be developed with a (DMM) 1kV high-interrupt rating. These DMM fuses are pretty huge.
I've shown some meters that were really bad in the fuse area.  As long as you are self certified, I guess you can get away with it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 06, 2017, 01:51:05 am
Trying out some StackPole ASRM series parts.  These are a metal film, flame retardant, pulse, blah blah safety resistors.  Also some tiny little EPCOS 500V PTCs.  The PTCs by themselves would survive a direct hit from the low voltage generator.  Well, 20 hits anyway.  With the high voltage generator turned up, they came apart with a single hit.  The resistors will also arc across with a single hit with this setup.  Combining the two, it survived 20 hits at 15KV before I turned it off.  No sign of any problems.  Way outside the ratings of both parts but may not be too bad a combo to try. 

Picture showing the StackPole part after the single hit. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 06, 2017, 05:40:03 pm
Time to try some OX series parts.   Surge ratings are much better.  May only need the one part.   
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on September 06, 2017, 10:49:44 pm
joeqsmith, it's good research you doing- anything to find a compact PTC/resistor solution for DMM front-end protection.

The only decent technical paper I found:
Pulse Handling Capabilities of Vishay Dale Wirewound Resistors (https://www.vishay.com/docs/49076/_wirewound_resistors_pulse_handling_capabilities_vmn_pl0396_1604.pdf)

"...The cross-over point is the time where significant energy starts to be dissipated not only in the [wirewound resistor's] wire itself but is now being dissipated into the core, leads, and encapsulation material. This is the point where the pulse is no longer considered a short pulse, but is now considered a long pulse."

So we are under the cross-over point and my hunch is the resistors are breakdown voltage-limited. OX/OY look pretty tough, but 3/4" is big and their 14kV/20kV rating with tiny 1,000pF discharge seems tame. I think 6kV for Cat. III is reasonable?

I considered Vishay WSC/WSN series (SMT) (http://www.vishay.com/product?docid=30102) but no info about 50usec impulse at high-voltages.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 07, 2017, 12:42:02 am
I wonder if we say 6KV peak, 1K resistor and a 1K PTC, does it divide for the pulse?  Many of the PTCs I look at will give thermal time constants in the tens of milliseconds with an amp applied.  At 3A and up, we are outside any of the parts I have found.   The plots are showing the voltage across both the PTC and series resistor and just across the PTC.   PTC is 1.3K R is 1K so not quite 50%.   At M1/M2, pulse is around 1KV peak.  Seems PTC does not react.  At C1/C2 1.8KV, we can see the PTC appears to be starting to open.   In the second set, the pulse is over 4KV and now we can really see the PTC starting to change.  A physically larger part, more thermal mass, may not budge at all.  This may be better as the PTC seems to be the weak link.       

The energy rating for the stackpole parts compared with the Ohmite OX is much worse.  If I could find the room, I would use the OY with the large PTC.   I also have some old Ohmite little devil and little demon parts that would work but those parts are no longer available.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 08, 2017, 03:04:11 am
A brand new Kasuntest ZT102 arrived today.  I started to run the normal functional test and discovered this meter will read Hz and duty cycle in the volts mode just like the AN8008 I had ran.  All three meters have the same revision PCB, came in the same box, included the same probes.   Now the really strange part, the SN of the latest meter is actually older than the last one I bought!  I assume this is setting in the PROM.  Maybe someone loaded the wrong image into the programmer that day but all the other features work correctly.   Maybe they recycle through serial numbers and this is actually a newer meter.   Also the springs used for the selector switch are silver like the first one I bought but all three use unique crystals.  Lots of variance in the process.

I have a few more things to test before I will do anything to the meter.  Maybe this weekend I will have some time to work on it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2017, 01:30:44 am
AN8008 CALIBRATION BASICS
I've figured out how to do calibration although I don't have the finer details worked out.  Here's what I know...

1. Short out J1 on the PCB (it's at the top right corner as you look at the PCB from the back of the meter)
2. Get your calibration reference ready and connected - in my case a 300 mA DC feed through the mA/A terminal and Common
3. Turn rotary control from off to the resistance position and CAL will appear on the display
3. Now WAIT until you hear a beep and then move the rotary control to the mA/A position - if you turn the rotary control away from resistance too quickly it doesn't show the values you've selected but moving the rotary switch around corrects that
4. Press [Set/Hold] (orange) button repeatedly until you see DC mA and a value will be displayed
5. Now you should see a value close to what you're providing the meter with, around 300 mA DC in my case
6. Press the [Range] (blue) button (quick press) to range down (but it only does it in 0.1 A increments)
7. Press and hold the [Range] (blue) button (long press) to range up (but it only does it in 0.1 A increments)
8. Press [Set/Hold] (orange) button to move off that setting (I think this is when the cal change just made is saved)
9. Move the rotary switch to off
10. Clear the link on J1 and power back on and test

As far as I can tell, the trick is to set the input to an exact value like 300 mA so you can set that value on the display during cal because you can't adjust the display to 303 mA so, for my slight discrepancy, I saw 298 mA displayed, I ranged down - I saw 200 mA, and then ,with a long press of [Range], ranged up and then I saw 300 mA displayed, pressed the orange button again and I was done.  Other parameters can be set by pressing the [Set/Hold] (orange) button repeatedly but you'll only see values corresponding to the rotary position selected so you'd leave it in the resistance position to cycle through the measurements associated with that position including resistance.

What I'm not clear about is when it actually stores a new calibration value, I guess that, once you use the [Range] (blue) button, it changes the calibration for that setting, and I think it saves it when - having got the display to show the value you want, you press the orange button once more. 

At first I did my above procedure providing 300 mA but ranged down to display 100 mA  and couldn't change that value because I hadn't figured out that a long press ranges up by that point.  So when I then switched off and removed the link, it had calibrated the meter to display 100 mA when 300 mA was supplied which it did.  I had to re-calibrate after I figured out that the long press increases the displayed value.

After I posted a video where I had modified the KZ102 (AN8002) to the capacitance readings were off about 100pF.  Someone had wrote me about modifying the contents of the PROM to realign it.   Seems like a lot of work.  Does anyone know if the above procedure applies to the AN8002 (and others) as well?  For capacitance and current, what are the standard values that are required?

I played around with the Z102's alignment.  Range is increment.  Hold is dec.  Mode select, selects the mode to align.  I made up some caps from my RLC meter as a reference.  There is a limit on what capacitors I can use and there is nothing it will accept in the 500pf range.  No null so seems I have to live with the capacitance or there is another trick.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2017, 04:13:55 pm
They always look so nice in the box when they first arrive.   Not much going on today so time to drag out the Dremel, iron and dope.  Maybe this time I will go in a little finer steps so we can get a better idea where it fails at. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2017, 11:15:03 am
Looks like the diode test voltage was lowered.  I lost the CMOS switch twice and had changed the part to higher voltage one and added a TVS to protect it.  Margins were pretty tight but the meter survived after this.  I was hoping they could find a fix as the 15V feature would have been very nice for checking high voltage diodes.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2017, 11:22:31 am
I made a second attempt at modifying the Kasuntest ZT102 to see if I could get it to survive some basic levels from my transient generators.

https://youtu.be/-V9JvFRjL78
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on September 12, 2017, 09:01:57 am
Nice one Joe! This must have been a hell of a lot of work. I actually found this one quite captivating. At one point I stopped it, but changed my mind and watched the entire clip because i was genuinly curious how it would end. Nice to see the meter survives now, did the Hioki not break down in a similar way?
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on September 12, 2017, 11:16:26 am
14 KV !! Awesome work Joe.  :-+
Very interesting video.
Appreciate the time and effort you give in order to make these videos.

3DB.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 12, 2017, 09:59:30 pm
Nice one Joe! This must have been a hell of a lot of work. I actually found this one quite captivating. At one point I stopped it, but changed my mind and watched the entire clip because i was genuinly curious how it would end. Nice to see the meter survives now, did the Hioki not break down in a similar way?

Yes the HIOKI I ran broke down because of some plastic that was not quite large enough and the meter was not electrically damaged.   This meter was similar in that it was not damaged. 

14 KV !! Awesome work Joe.  :-+
Very interesting video.
Appreciate the time and effort you give in order to make these videos.

3DB.
Well, a solid 10KV anyway.   You want 14KV, you got it.   This was really the goal, get it up to the levels that the most robust handheld meters I have tested survive at.  There is not a lot of science to it but I hope that it shows that its not something that is all that difficult to achieve.  I really see no reason that especially the $100 and up meters will not survive to the levels this modified $15 Kasuntest meter will.   

https://youtu.be/dEwLuiYX5cQ
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 14, 2017, 12:20:36 am
Someone had requested the dead meters be drop tested. 

https://youtu.be/PYFs9F0scDQ
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on September 14, 2017, 12:27:05 am
Joe, you're really widening your equipment-destroying horizons. Break a leg...er...an instrument!
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on September 14, 2017, 07:32:35 pm
I worked for a Telecom manufacturer and they did 1m drop testing on hard floors.
Scared the !Q@#%^@#^ out of me, mechanical engineers go in the lab and start throwing them down. SMACK! Buttons flying everywhere.
Results seemed so variable, if the display hit or the buttons hit first. It was a free-fall standard, but they threw them down to find the design weakness.

The main point was the desk phone would not crack or break under a typical slide off your desk scenario.
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on September 14, 2017, 09:23:18 pm
A two floor drop and just a few scratches, seems reasonably robust to me. It may be helped by the fact they weigh almost nothing. It does seem that good spring material is difficult to get, i have had issues with fuses not connecting properly in cheap meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 15, 2017, 03:14:08 am
The three CEM DT9939s. These are 40K count, have an internal RF link and tri-display.  They also have basic features like AC+DC.    A few of us bought the CEM from Ruby Electronics when they were selling them for $120.  I've made a review of them and showed many problems with the meter on the right.   

The meter in the center is from work.  It was just calibrated and turned five years old.  The meter has had a rough life.  I loaned it out once and the person had turned the knob past the dead stop.   A few times it came back with blown fuses.  Then I put it through a fair amount of abuse myself.  People say how they never use their meters about 40 deg C.  This meter has been used above those temps with the RF link.  I've dropped it a few times and you can see how the case has discolored with time from being out in the sun.

We would never have them generate a calibration report for a handheld so I don't have any records on drift.  It has never been aligned and I thought for fun I would compare it against some of my home equipment.   
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on September 15, 2017, 04:15:26 am
Looking forward to the review, Joe. :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 15, 2017, 06:01:36 pm
Happy Birthday EX540

https://youtu.be/Yih7D23z7vE
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 16, 2017, 08:51:00 pm
I was asked if all I did was add more dope to get the Kasuntest to survive at higher levels without breaking down.  This video shows what it ended up looking like.  More than just dope.   

I also thought I would show how the current measurement compares with two other meters. 

https://youtu.be/EkQ6CCj7jmU
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on September 16, 2017, 09:28:58 pm
AMAZING, originally a $20 meter, guessing after time, parts, and labor, now CUSTOMIZED at over $500!
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on September 16, 2017, 09:46:09 pm
AMAZING, originally a $20 meter, guessing after time, parts, and labor, now CUSTOMIZED at over $500!
The exercise is not to waist time and money (maybe it's pastime with a purpose?). Joe's channel is the only one I know of that stands up to poor DMM manufacturers by sharing what could have been done but wasn't (for a whole host of reasons).
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on September 16, 2017, 10:05:53 pm
AMAZING, originally a $20 meter, guessing after time, parts, and labor, now CUSTOMIZED at over $500!
The exercise is not to waist time and money (maybe it's pastime with a purpose?). Joe's channel is the only one I know of that stands up to poor DMM manufacturers by sharing what could have been done but wasn't (for a whole host of reasons).

You misinterpreted my post, I love the time and effort Joe takes to produce his videos, not sure where he finds the time. My point was there are probably some that would love one of these tiny meters that are customized to such a higher quality degree, but it would cost TOO MUCH in reality. So again, a $20 meter can be "upgraded" to much better grade, but I'm sure Joe would laugh at being able to make any money after his time, labor, and parts, even at $500!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 17, 2017, 03:05:13 am
AMAZING, originally a $20 meter, guessing after time, parts, and labor, now CUSTOMIZED at over $500!
The exercise is not to waist time and money (maybe it's pastime with a purpose?). Joe's channel is the only one I know of that stands up to poor DMM manufacturers by sharing what could have been done but wasn't (for a whole host of reasons).

You misinterpreted my post, I love the time and effort Joe takes to produce his videos, not sure where he finds the time. My point was there are probably some that would love one of these tiny meters that are customized to such a higher quality degree, but it would cost TOO MUCH in reality. So again, a $20 meter can be "upgraded" to much better grade, but I'm sure Joe would laugh at being able to make any money after his time, labor, and parts, even at $500!

If you would like a better handheld meter the best option is to just buy one that meets your needs.   If you are interested in seeing a particular product  improved, I would contact the manufacture and let them know what features you are interested in.  I would never suggest anyone attempt to modify their handheld meter like I have shown.  I certainly would never offer any sort of a modified handheld meter or kit for sale.  I would see this as nothing more than a scam.  Worse, you are putting people at risk over a few dollars.  Sorry, not interested.

I did hook up the programmer and downloaded the contents of the PROM for the ZT102.  I went ahead and opened the window for the Amps range so the uA no longer beeps.  I also moved down the warning and over range limits.  I started to look at the switch and it does not seem like there is a clean way to change it. 

This is the unmodified contents:
:10000000FFFFFFFFFFFFFFFFFF5200BE0070C903AD
:100010001017381844026E50644B3C3C0AFF40FFF6
:10002000C798E38264009600008000803B7E826F68
:100030004E020930010A9AF60984F509E8030A001C
:1000400000010001000798006400640064000000E3
:1000500000800080008000800080008000800080A0
:10006000817E00830100922A000000000000000051
:1000700053810080C57DE07C180100000000000075
:100080000000000000001013000E00070012030122
:100090000000000000001115000F0009000004021C
:1000A00000000000000000000000000A0000000046
:1000B00000000000000000000000000B0000000035
:1000C0000D0002100D00032020000320200003106B
:1000D0000080008000800080410003050D000220A8
:1000E0000080008000800080008000800080008010
:1000F0000080FFFFFFFFFFFF5AC7CC0F0FA20000D9
:00000001FF


 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 17, 2017, 05:37:57 pm
What ever happened with Randomtronics?   I was watching his review of the AN8002 and I am not so sure the RMS conversion is as bad as it was made out to be in the video so I though I would run a quick test of my own to compare the ZT102 with a few meters. 

https://www.youtube.com/watch?v=KHjTEO4gr6g (https://www.youtube.com/watch?v=KHjTEO4gr6g)

Randomtronic's video may be found here:
https://youtu.be/oNss6h0Zu98 (https://youtu.be/oNss6h0Zu98)

Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on September 17, 2017, 06:54:26 pm
Joe, did you read the first few comments on the YouTube page? There were some that pointed out his little mistake that he then acknowledged. All a bit over my newbie head.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 17, 2017, 07:14:01 pm
Yes, I read them.  I thought I would try and make it a little clearer. 


Rob C1 month ago

I am still confused by the comments is this meter true RMS or not??

Reply•   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 18, 2017, 12:53:40 am
Someone asked about how these changes to the ZT102 effected its frequency response. 

https://youtu.be/0nxjyqJf2jI?t=2
Title: Re: Handheld meter electrical robustness testing.
Post by: sleemanj on September 18, 2017, 02:18:02 am
What ever happened with Randomtronics? 

I think he must have moved or something and his equipment is still in packing boxes going by recent replies to comments.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on September 18, 2017, 03:23:41 am
True-RMS (calculation) is AC coupled in the DMM IC used in the AN8002, AN8008 etc.
I thought any DC offset is ignored as part of the calculation.

But some DMM's include the DC portion if using the good old analog AD536 (http://www.analog.com/media/en/technical-documentation/data-sheets/AD536A.pdf) true-RMS converter (which costs much more than a cheap multimeter...)
Joeqsmith, didn't you already try adding a DC offset to a waveform, many posts prior?

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on September 18, 2017, 11:08:55 am
True-RMS (calculation) is AC coupled in the DMM IC used in the AN8002, AN8008 etc.
I thought any DC offset is ignored as part of the calculation.

But some DMM's include the DC portion...

I'd argue that it's more correct to include the DC portion because not all waves are symmetrical.

Where there's a DC offset it might be better to have a vpp function but I don't recall seeing that on a meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on September 18, 2017, 05:30:10 pm
I have a DMM with a switch for true-RMS AC+DC, or true-RMS AC only. Basically switches in/out a coupling cap to the true-RMS converter IC.

On the grid, pretty much no DC offset due to transformers. Missing DC is OK there, but not doing measurements on SMPS DC bus etc.

The DMM IC has result registers for DC and AC true-RMS (LPF) so they could be both used but the econo MCU is very basic and can't do math like multiply, square-root etc.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 19, 2017, 02:16:46 am
True-RMS (calculation) is AC coupled in the DMM IC used in the AN8002, AN8008 etc.
I thought any DC offset is ignored as part of the calculation.

But some DMM's include the DC portion if using the good old analog AD536 (http://www.analog.com/media/en/technical-documentation/data-sheets/AD536A.pdf) true-RMS converter (which costs much more than a cheap multimeter...)
Joeqsmith, didn't you already try adding a DC offset to a waveform, many posts prior?
Good memory.  Yes I did run some tests with DC but maybe not for the reason you suggest.  This was really to show the problem with the auto range where the meter shows a low AC voltage.  These meters have been the worse I have seen for this.  So as long as you are aware of that, you could work around it (add a manual range button as I show). 

In the following pictures, I have a sinewave that is fullwave rectified.  This drives the three in parallel.  I show both the AC and DC content of the ZT102 compared with the Fluke 189.   The 189 can calculate the AC+DC which obviously the Kasuntest can not.  So back to pulling out your calculator.  But it's was only $15.  I think the cheapest meter I bought with AC+DC was when Ruby Electronics was selling the CEM DT9939 for $120. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 24, 2017, 10:13:20 am
Video comparing the leads supplied with the Kasuntest with others I have looked at.   I also wanted to see if the modified current input would survive if the fuse was blown. 

https://youtu.be/fG61v8UgzA8
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 30, 2017, 09:31:24 pm
What on earth does a home made tuning fork have to do with a hand held multi-meter?   

https://youtu.be/QBho9XD7VPQ
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on September 30, 2017, 10:33:22 pm
Cool mode switch test fixture. Having it running in the background was nice while reading the forum.

I guess this upgrades the thread to, "Handheld meter electrical robustness testing."
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 01, 2017, 12:03:04 am
Cool mode switch test fixture. Having it running in the background was nice while reading the forum.

I guess this upgrades the thread to, "Handheld meter electrical robustness testing."

You can't have a proper home lab without a Panavise.  That vise gets used for all sorts of quick little tests and such.  Very handy. 

After your comment about my drop testing and expanding my testing, I was trying to think how to one up it..  lol.  Not sure that I will add the switch cycling to my normal tests or not.  Really just trying some things out.    Some meters I have purchased, the switch design was so bad the meters did not work out of the box.  I have a friend who just had a newer meter fail and sure enough, it was the switch.

Feel free to offer any suggestions.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on October 01, 2017, 12:28:10 am
I had a meter where the switch was bad from the start. Useless. You could not even be sure in what mode you are.

I actually have good experience with the cheapo DT/Harbor Freight type meter (about $2-4 on eBay depending on model or moment). No problems with the switch even with frequent rotation (e.g. turn off after checking, turn on to check again, turn off... to preserve battery - Harbor Freight one has a power switch but eBay China ones do not). But this is different for people who really use their meters (e.g. every single day, for work). They will see switch problems much sooner.

That looks like a really nice rig to test switch duration.
If temperature is an issue with the tests (as in real use it's not likely to get things too heated), is it possible to add some pause after every x rotations?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 01, 2017, 01:04:54 am
I had a meter where the switch was bad from the start. Useless. You could not even be sure in what mode you are.

I actually have good experience with the cheapo DT/Harbor Freight type meter (about $2-4 on eBay depending on model or moment). No problems with the switch even with frequent rotation (e.g. turn off after checking, turn on to check again, turn off... to preserve battery - Harbor Freight one has a power switch but eBay China ones do not). But this is different for people who really use their meters (e.g. every single day, for work). They will see switch problems much sooner.

That looks like a really nice rig to test switch duration.
If temperature is an issue with the tests (as in real use it's not likely to get things too heated), is it possible to add some pause after every x rotations?

That one CEM I bought would not even turn on because of the switch.  The plastic needed some adjustments with the razor.  lol.   I would expect the mechanics to give out long before any electronics (assuming normal use).  When I starting paying over $100 for a meter, I really expect the company to have the basics down, like the switch design.   Then again, I am sure they think we sell more meters if they only last a few cycles.  lol.
 
The temperature problems were a result of running it too fast.  The plastic started to get warm enough to bind.   Once it cooled it was fine.  I have a dwell time now that it sits for, along with acceleration, deceleration, max speed.   Basically, everything is adjustable with these M-Drive motors.   I really don't need it to run all that fast so normally temperature shouldn't be a problem.   

I was looking at the old Fluke my friend gave me.  That meter is pretty old and the switch still looks new.   Maybe 5000 cycles is not really enough.   It's all up in the air right now. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 01, 2017, 01:37:50 am
After your comment about my drop testing and expanding my testing, I was trying to think how to one up it..  lol.  Not sure that I will add the switch cycling to my normal tests or not.

LOL, what will Joe come up with next?

I haven't experienced a bad switch, yet, so it hadn't crossed my mind. However, it does seem to be an issue with some meters. Flaking metallic bits inside the meter could lead to all sorts of bad outcomes. It may be a useful addition to your testing repertoire. At least it's automated so you can do other things as it runs.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 01, 2017, 02:23:18 pm
After your comment about my drop testing and expanding my testing, I was trying to think how to one up it..  lol.  Not sure that I will add the switch cycling to my normal tests or not.

LOL, what will Joe come up with next?

I haven't experienced a bad switch, yet, so it hadn't crossed my mind. However, it does seem to be an issue with some meters. Flaking metallic bits inside the meter could lead to all sorts of bad outcomes. It may be a useful addition to your testing repertoire. At least it's automated so you can do other things as it runs.
Any metallic flakes between the contacts would effect how the meter handles the surge tests.  If it's bad enough, I could see it having an effect on the normal operation.   

The problem I see with running a test like this is that its destructive.  I can't run it before I run my other tests and many times, the switches are damaged from my other tests so I can't really run any sort of cycle testing afterwards. 

In the meantime, someone asked about running a UT61. 

https://youtu.be/1h6UaF_SwKs
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on October 04, 2017, 07:58:42 pm
Didn't the Kasuntest you originally ran have some kind of lubrication on it? I'm actuaaly quite surprised both meters you tested seem to be near unaffected by so many cycles. I'd be worries about the vias under the wipe contacts, but given the limited wear this probably won't ever be an issue before the meter (or the user) dies. :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 04, 2017, 11:52:11 pm
Didn't the Kasuntest you originally ran have some kind of lubrication on it? I'm actuaaly quite surprised both meters you tested seem to be near unaffected by so many cycles. I'd be worries about the vias under the wipe contacts, but given the limited wear this probably won't ever be an issue before the meter (or the user) dies. :P

I have bought four ZT102s and one AN8008.  None of these had any sort of lubrication that I saw.  I have not looked at that last ZT102.   I did apply some lubrication to the second ZT102's ball detents, along with swapping out the springs from the first unit to try and get the switch to have a better feel to it.  I did the same thing to the third unit. 

Again, I would not read much into these initial tests.  The meters have all been apart and badly abused.  It's possible for example that when I forced all that current through the contacts I softened them and changed their tension.   Maybe now they are pushing down with less force and this is why there is little wear.  I have no idea nor did I care.  Thinking a virgin meter would behave the same would make no sense what so ever.   

I have been looking for manuals that call out the number of cycles they rate their switches to.  I have yet to find anyone providing this detail.  Strange and you would think it would be common. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 05, 2017, 02:04:15 am
my 102 had clear grease smeared/sprayed onto the pcb contacts,
but the plastic detents had very small grease traces - like it had been applied to the balls rather than the plastic.
maybe they did it to hold the balls to the springs during assembly.  ::)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 05, 2017, 02:20:22 am
That's strange.  But then again, ever meter I looked at had a different xtal and two have the VAC frequency/duty cycle and two do not, plus different springs.  Must be a total crap shoot with them.

Is yours an actual Kasuntest ZT102 or some other branded version of it?  I would not mind seeing a clear picture of the grease in the switch area if possible.   
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 05, 2017, 03:00:45 am
mine is ANENG badged,
cant do pics because i re-greased it.
it has the freq/duty on it btw, but not printed on the case.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 05, 2017, 03:05:40 am
btw, are the switch contacts the same as centech / harbour-freight meters?

i have a second 102 from someone who lost 2 contacts while messing in it after they managed to blow up the transient suppressor somehow!!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 05, 2017, 03:42:48 am
Thanks anyway.  I only had that one ANENG AN8008. I wonder if they removed the grease as a cost saving measure.  Really, why not? 

I think that PTC was only rated for 500V.  Still, under normal use, it would not be a problem as most people don't try and read voltage with the resistance mode, or when the meter is off. 

From all of the meters I have looked at, it looks like there are only a few variations of switch contacts.  Shown are the Kasuntest next to a HF free meter.  Note that I cycled the HF meter and the contacts are a bit worn but I've seen much worse. 

 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 05, 2017, 04:07:58 am
thanks, they look compatable.
just have to find an old centech now.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 05, 2017, 04:58:51 pm
it's not the ptc, it's the bi-directional diode on the left of the battery box that protects the current range afaik from overvoltage.
meter runs fine without it using my other casing.

i will fit a new one though - and probably up the fuses to 20mm ceramic "FF" rated ones.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 06, 2017, 12:11:41 am
The TVS makes much more sense than the PTC.  With the fuse they have in there, I would not be surprised with a quick measurement of how much current comes out of a house outlet may do it in.   That or replace that tiny fuse with some wire.... 
lol.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 06, 2017, 04:31:19 am
the guy i got it from was very reluctant to tell me what he did, but from some comments about the meter that slipped out,
i think he was trying to take a low current reading from the mains!!
obviously didnt read the manual where it states 35v max!!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 06, 2017, 11:41:38 pm
Makes sense.  When I was researching Gossen products I read a post where a guy damaged a new meter they had bought at work I believe with the current input and AC mains.  It may be more of a problem than people are aware of.  If you watched that last video I made where I tested the current inputs on the standard ZT102 and AN8008 compared to the one I modified, that fuse Dave provided makes all the difference in the world.   

But again, to be clear, I doubt that would be a problem with low voltages.  So a hobbyist playing with 5V and less digital logic, it's should be much less of a risk damaging the meter.  Even the unfused free HF meters may be just fine.   Then again, this is not the group that should ever be concerned with any of the low energy surge tests I run.  These are the people who tell me how my tests far exceed what these meters would ever see.  Let's see todays post was "... and all this high voltage warnings are also useless - who measures above 1000v with such meter,..."  Or they tell me how I am doing direct discharges with capacitors into these meters and how stupid it is.   Or they watch them and decide because they just saw their meter take a 10KV hit that it could be connected to a MOT secondary.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 07, 2017, 05:28:42 am
well, some people do some extreme things when they have no choice.

i have read of a guy checking the 3KV output of a fence charger he repaired,
first with a fluke - killed it!
then with a low end uni-t that actually gave him the reading!!!!!

another guy testing the neck socket of a crt without knowing how high the focus voltage is.

so low current HV is more "available" than people realise.
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on October 07, 2017, 01:29:26 pm
Didn't the Kasuntest you originally ran have some kind of lubrication on it? I'm actuaaly quite surprised both meters you tested seem to be near unaffected by so many cycles. I'd be worries about the vias under the wipe contacts, but given the limited wear this probably won't ever be an issue before the meter (or the user) dies. :P

I have bought four ZT102s and one AN8008.  None of these had any sort of lubrication that I saw.  I have not looked at that last ZT102.   I did apply some lubrication to the second ZT102's ball detents, along with swapping out the springs from the first unit to try and get the switch to have a better feel to it.  I did the same thing to the third unit. 

[...]
What is it then that you are mentioning here at 9:21 in this video (https://www.youtube.com/watch?time_continue=561&v=HrcxnbkkhYg)? There was definitely something there.

I have disassembled mine to check for any residue, but I found the board to be completely clean. I did however use the opportunity to put a tad of grease in the detent race. There seems to have been a very minimal amount of it already present, but they supply ball bearings and steel parts that way quite often to prevent corrosion.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 07, 2017, 02:23:18 pm
Didn't the Kasuntest you originally ran have some kind of lubrication on it? I'm actuaaly quite surprised both meters you tested seem to be near unaffected by so many cycles. I'd be worries about the vias under the wipe contacts, but given the limited wear this probably won't ever be an issue before the meter (or the user) dies. :P

I have bought four ZT102s and one AN8008.  None of these had any sort of lubrication that I saw.  I have not looked at that last ZT102.   I did apply some lubrication to the second ZT102's ball detents, along with swapping out the springs from the first unit to try and get the switch to have a better feel to it.  I did the same thing to the third unit. 

[...]
What is it then that you are mentioning here at 9:21 in this video (https://www.youtube.com/watch?time_continue=561&v=HrcxnbkkhYg)? There was definitely something there.

I have disassembled mine to check for any residue, but I found the board to be completely clean. I did however use the opportunity to put a tad of grease in the detent race. There seems to have been a very minimal amount of it already present, but they supply ball bearings and steel parts that way quite often to prevent corrosion.

I really don't know what that stuff was.   It almost looks like when the board was washed that something dripped down.  Normally with grease it will not just wipe off.  It smears and it is slick.  I've seen a few where they use it and it's always been more translucent and applied around the contacts, not dripped across the board like this one.  I have not looked at that 4th unit to see if there was anything in it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 07, 2017, 02:47:26 pm
well, some people do some extreme things when they have no choice.

i have read of a guy checking the 3KV output of a fence charger he repaired,
first with a fluke - killed it!
then with a low end uni-t that actually gave him the reading!!!!!

another guy testing the neck socket of a crt without knowing how high the focus voltage is.

so low current HV is more "available" than people realise.
It seems I read one about a fencer as well but I don't recall the Fluke/UNI-T part.  It may have been a whole different case. I imagine this sort of thing happens more frequently than what is ever posted. 

I have a friend who was doing something similar trying to read the primary side off the coil in a lawn tractor.   The first two meters he tried would not give a stable reading, so he used one of the UT210E clamps and it worked.   No meters were damaged in that case.

I play around a fair amount with low current higher voltages which is partly why I am interested in running the meters this way.   I would never think of hooking up a meter to a fencer but then again, I did try that fly swatter after Scott posted about it.   :-DD 

Here's this morning's comment for the day:
Quote
Your video actually shown that this dirt-cheap device is at very least conform with CATII/300, means it's compeletely safe to be used in electrical household.
According to spec CATII/300 it should be capable to withstand upto 2500V impulse voltage. Note that It said: impulse,  a voltage spike, not a contstant current.

Why does he feel my tests show the meter is completely safe?  People can't read, don't want to take the time to read or they just like to state their opinions no matter if they know something about it or not.     I can only guess what that last sentence means.   It's too bad these people won't post their opinions in this forum.  If you could actually get some constructive dialog (rare), it may actually help the group.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 07, 2017, 05:53:35 pm
Here's this morning's comment for the day:
Quote
Your video actually shown that this dirt-cheap device is at very least conform with CATII/300, means it's compeletely safe to be used in electrical household.
According to spec CATII/300 it should be capable to withstand upto 2500V impulse voltage. Note that It said: impulse,  a voltage spike, not a contstant current.

Why does he feel my tests show the meter is completely safe?  People can't read, don't want to take the time to read or they just like to state their opinions no matter if they know something about it or not.     I can only guess what that last sentence means.   It's too bad these people won't post their opinions in this forum.  If you could actually get some constructive dialog (rare), it may actually help the group.
Living in modern times one can surely tell how people read things diagonally, can't comprehend a text or are simply armchair judges/commentators/etc...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 08, 2017, 04:21:34 pm
Living in modern times one can surely tell how people read things diagonally, can't comprehend a text or are simply armchair judges/commentators/etc...
It works fine if you are living in mom and dads basement playing video games and the height of your week is if you are the first person to comment on a freshly uploaded YT video.  :-DD  It's pretty rare I will get good constructive criticism that could actually help.  Some of the best ones I have gotten were using the HOLD button when comparing meters and fixing the color.   :-+   

I went to look for a new quote for the day and the last one I posted was pulled. :-DD  I guess my response or posting here must have upset them.  No new good quotes today so we need to work backwards.   
Quote
I helped you by bringing you down to planet earth, use a meter within its specs and dont create mythical conditions. Next you will compare it with weather sealed devices? Dont play god, other people have brains too.
 
I assume they believe in a God/s, have a brain but just don't like me creating mythical conditions.  Am I the only one who find humor in these posts? 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 09, 2017, 01:58:00 am
Quote
... use a meter within its specs and dont create mythical conditions. Next you will compare it with weather sealed devices? Dont play god, other people have brains too.
 
I assume they believe in a God/s, have a brain but just don't like me creating mythical conditions.  Am I the only one who find humor in these posts?

They're quite humorous, indeed. "[U]se a meter within its specs and dont [sic] create mythical conditions" — where's the fun in that?
Title: Re: Handheld meter electrical robustness testing.
Post by: lem_ix on October 09, 2017, 02:19:35 am
Most people like regurgitated, low attention span compliant videos with a buy or don't conclusion, many "professionals" included. Similarly they need confirmation that their el cheapo uni-t is safe(whatever that means) because they couldn't afford the "safe" fluke. Was amazed recently hearing a local electrician / electronics hobbyist saying how he uses his 5$ dmm for work instead of his 100$ Sanwa so that he doesn't destroy it  :palm:

Maybe in a few years you'll notice Darwinian evolution in your comment section  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 09, 2017, 02:29:44 am
Yeah, some people have "different" priorities. :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on October 09, 2017, 08:19:58 pm
Didn't the Kasuntest you originally ran have some kind of lubrication on it? I'm actuaaly quite surprised both meters you tested seem to be near unaffected by so many cycles. I'd be worries about the vias under the wipe contacts, but given the limited wear this probably won't ever be an issue before the meter (or the user) dies. :P

I have bought four ZT102s and one AN8008.  None of these had any sort of lubrication that I saw.  I have not looked at that last ZT102.   I did apply some lubrication to the second ZT102's ball detents, along with swapping out the springs from the first unit to try and get the switch to have a better feel to it.  I did the same thing to the third unit. 

[...]
What is it then that you are mentioning here at 9:21 in this video (https://www.youtube.com/watch?time_continue=561&v=HrcxnbkkhYg)? There was definitely something there.

I have disassembled mine to check for any residue, but I found the board to be completely clean. I did however use the opportunity to put a tad of grease in the detent race. There seems to have been a very minimal amount of it already present, but they supply ball bearings and steel parts that way quite often to prevent corrosion.

I really don't know what that stuff was.   It almost looks like when the board was washed that something dripped down.  Normally with grease it will not just wipe off.  It smears and it is slick.  I've seen a few where they use it and it's always been more translucent and applied around the contacts, not dripped across the board like this one.  I have not looked at that 4th unit to see if there was anything in it.

Okay, it was no lubrication then. On film it was difficult to judge (but in your defence: you did say it wiped off easily). It didn't hurt functionality as flux would.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 09, 2017, 10:12:22 pm
Okay, it was no lubrication then. On film it was difficult to judge (but in your defence: you did say it wiped off easily). It didn't hurt functionality as flux would.
I am not sure what would have been the long term effects of it, not knowing what it was.  It looked like scum from a wash system and may have had some flux residue in it.  It would explain the drip effect.  If that's what it was, I could see it causing problems.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on October 11, 2017, 01:07:51 pm
I do remember trying to wash a PCB out of an audio amplifier in a dishwasher once after I had read this method was used in the Tektronix labs to reduce leakage on the board. It did not work... :( They used something which I found later to have been called "Kelite", but I have not been able to find a source for it, just a bunch of people that also did not have it.

Using ordinary dishwasher blocks (wihout salt and shine) all the flux residue on the board turned white and did not wash off, causing it to look similar to your Kasuntest. One would needed to scratch it off my PCB with a finger nail rather than wiping it, but it might still be similar stuff.

On a Dutch forum I found people that had PCBs that turned white in a similar way due to water ingress. It seems like water turns flux residue white, but only on the surface, because wettening the affected areas with isopropyl alcohol immediately removed the white effect and showed the brown colour underneath.

(https://farm1.staticflickr.com/577/22676433925_06f391a5d4_z.jpg) (https://farm1.staticflickr.com/577/22676433925_be474e69c9_o.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 25, 2017, 05:12:53 pm
A few people have been asking me about more specialized handheld meters.  One of the most common request I get is for meters with an oscilloscope function.  Not a graphing meter like the UT181A I looked at but more like the Fluke 97 but smaller.  Another area people seem to be interested in is handhelds designed for the automotive market.  TPI offers a few different ones.   

So if you are interested in seeing a more specialized meter ran, feel free to chime in.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 25, 2017, 11:32:01 pm
I thought I would have a look fore meters that could read engine RPM.  I'm sure there are better ones out there.

atdtools.com 5585
INNOVA-3340
PDI PDI 895

Harbor Freight has something
https://www.harborfreight.com/lcd-automotive-multimeter-with-tachometer-kit-95670.html (https://www.harborfreight.com/lcd-automotive-multimeter-with-tachometer-kit-95670.html)

Title: Re: Handheld meter electrical robustness testing.
Post by: Lightages on October 25, 2017, 11:37:36 pm
I thought I would have a look fore meters that could read engine RPM.  I'm sure there are better ones out there.

atdtools.com 5585
INNOVA-3340
PDI PDI 895

Harbor Freight has something
https://www.harborfreight.com/lcd-automotive-multimeter-with-tachometer-kit-95670.html (https://www.harborfreight.com/lcd-automotive-multimeter-with-tachometer-kit-95670.html)

I don't know if you want to look at another Brymen, but the BM315 and BM319 are automotive meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 26, 2017, 02:12:51 am
I downloaded the manual as am a little confused about some of the functions.  Seems like it has the basics covered. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 26, 2017, 11:55:09 am
The HONGDA HD AT2150B, $30.    Manual ranging but has separate current inputs.    Some come with an inductive clamp, others like this one do not.   
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on October 26, 2017, 12:14:57 pm
Since this thread has now branched into automotive specific meters, anyone know of any that can be used with one or two cylinders, instead of the usual 3 - 8?  I have more of a need for a meter that can read RPM's of single or dual cylinder small engines.

Paul
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 26, 2017, 01:09:53 pm
wouldnt that just be the frequency function, and multiply the reading by 30 or 60?

Title: Re: Handheld meter electrical robustness testing.
Post by: Gregg on October 26, 2017, 05:30:25 pm
Since this thread has now branched into automotive specific meters, anyone know of any that can be used with one or two cylinders, instead of the usual 3 - 8?  I have more of a need for a meter that can read RPM's of single or dual cylinder small engines.

Paul
Fluke 88 lists an optional inductive pickup that clips around a single spark-plug wire and will measure RPM for a single or multiple cylinder gasoline engine; not good for diesels.
I have an older model Fluke 88 that came with the pickup in a kit form that works very well. 
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on October 26, 2017, 08:59:33 pm
A few people have been asking me about more specialized handheld meters.  One of the most common request I get is for meters with an oscilloscope function.

Are there any "cheap" options? I know only Flukes, they cost a fortune (even old ones).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 26, 2017, 10:31:21 pm
Since this thread has now branched into automotive specific meters, anyone know of any that can be used with one or two cylinders, instead of the usual 3 - 8?  I have more of a need for a meter that can read RPM's of single or dual cylinder small engines.

Paul

The Brymen seems to.  It's the only manual I have downloaded so far.

wouldnt that just be the frequency function, and multiply the reading by 30 or 60?

The RPM input for many of these meters have an adjustable trigger level.  I would assume they are designed to work with the noise you would normally see.  Math wise it would depend on the configuration.  Any automotive meter I would expect would do the math for RPM as a minimum.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2017, 11:42:00 am
Looking at the Harbor Freight meter, I don't care for the manual range.  Another problem seems to be that they don't handle all the various modes.  So you may need your calculator. 
 
Quote
If clamping to any spark plug wire
after the distributor, multiply the
displayed reading by the number of
cylinders x 10 to obtain the RPM value.

If clamping to ignition line I or II, multiply
the display reading by 20 to obtain
the actual RPM value of the engine.

I've never heard of all-sun or e-sun.  They offer a few different ones. 
http://www.all-sun.com/en/p.aspx?px=19 (http://www.all-sun.com/en/p.aspx?px=19)
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 27, 2017, 12:08:44 pm
these rpm systems are very limited in use btw,
modern cars all use coilpacks, so your meter needs to have a low voltage input for the function.
even a number of pre-coilpack cars used a system of firing a stream of sparks rather than a single discharge, or in the case of alpha-romeo a redundent spark caused by pairing cylinders to a single HT lead.
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on October 27, 2017, 02:48:29 pm
Define "cheap".  A few of the meters I listed were under $50.

Well, under 120euro in EU in a reasonably good condition... Flukes are much more expensive here than in US.

Although, I may not understand what I'm asking, handheld scopes may have isolated inputs which cost a fortune.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2017, 04:28:05 pm
Define "cheap".  A few of the meters I listed were under $50.
Well, under 120euro in EU in a reasonably good condition... Flukes are much more expensive here than in US.

Although, I may not understand what I'm asking, handheld scopes may have isolated inputs which cost a fortune.
Any idea what features you want, or is your only criteria that it is cheap?   

I did hear back from Brymen.  Not too surprised as they are always pretty quick to respond.  Their response triggered another question. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2017, 04:44:01 pm
these rpm systems are very limited in use btw,
modern cars all use coilpacks, so your meter needs to have a low voltage input for the function.
even a number of pre-coilpack cars used a system of firing a stream of sparks rather than a single discharge, or in the case of alpha-romeo a redundent spark caused by pairing cylinders to a single HT lead.

The three I have looked at support a low voltage input as well.  Basically, you just don't use the clamp. 

Your comments about the stream of sparks and redundant spark is why the math may not be as simple as you suggest.  Wasted spark is fairly common and I would expect a decent meter would handle it for both 2 and 4 strokes.  If you watch my videos, you may be aware I run an MSD ignition that will put out a variable number of pulses per cycle based on the crank speed.  The meter would need something akin to a blanking circuit to handle this.   This is one of my questions to Brymen. 
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on October 27, 2017, 11:01:04 pm
Any idea what features you want, or is your only criteria that it is cheap?   

Sorry, there was misunderstanding from my side. I wanted to know more about "scopemeters". I thought it's a DMM and oscilloscope in one unit. But it looks like it's just a portable oscilloscope, not so much a multimeter. So, I guess, any handheld oscilloscope can be called a "scopemeter".
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on October 27, 2017, 11:17:01 pm
Any idea what features you want, or is your only criteria that it is cheap?   

Sorry, there was misunderstanding from my side. I wanted to know more about "scopemeters". I thought it's a DMM and oscilloscope in one unit. But it looks like it's just a portable oscilloscope, not so much a multimeter. So, I guess, any handheld oscilloscope can be called a "scopemeter".

There's this:

(https://i.imgur.com/R4nqaTY.png)

Quote
FEATURES:
ET201 emphasis on functional combination for field testing process, not to replace the meter. It reflects the high-tech, using a dedicated chip has, as the wave function, you can view the waveform signal 10KHZ within. As a large number of measuring instruments Waveform, you will find ET201 is the most affordable one, spend the price of a multimeter, you can have a table can be seen, as the wave of the waveform, value for money!
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on October 28, 2017, 12:26:28 am
There's this:

I know about it, it's horrible (imho). There are reviews on youtube. But it is not even autoranging... Although, I can't name anything better for the price.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 28, 2017, 01:11:54 am
I've had a few people ask me about the CEM DT-9989.   A member here was posting about their bad luck trying to buy one.  UNI-T has something as well but seems again that I have not seen anyone who thought it was useful.

I have a need from time to time for a small battery powered scope and ended up with a couple of old Fluke 97s.  These are basically a meter and scope combined.  They work alright for what they are but there are no parts available for them. 
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on October 28, 2017, 02:15:14 am
The meter I linked above mentions 10 kHz, but can't even DSO138 work with faster signals? Okay, it's not a multimeter... but it is small, cheap, and can work on batteries (I guess). It didn't get too many shining reviews (at least the ones I've seen). Getting the unsoldered version is riskier, as it would be hard to be absolutely sure or prove that there wasn't an issue with soldering the kit together if something doesn't work.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 28, 2017, 05:55:55 am
Yeah, looks nice, but only 10kHz? Might as well get one of these:

For $21, DSO150 (https://www.aliexpress.com/item/Fully-Assembled-Orignal-Tech-DS0150-15001K-DSO-SHELL-DSO150-DIY-Digital-Oscilloscope-Kit-With-Housing-case/32826373665.html), nice enclosure, assembled, 200kHz. Pair it with a nice, safe, DMM.

Or for $46, get a DSO-112A (https://www.aliexpress.com/item/DSO-112A-TFT-Mini-Digital-Oscilloscope-Touch-Screen-Portable-USB-Oscilloscope-Interface-2MHz-5Msps/32629013364.html),  2 MHz, 5 Msps.
Title: Re: Handheld meter electrical robustness testing.
Post by: totalnoob on October 28, 2017, 02:17:45 pm
Thank you Joe, I will have to look into those.

Paul
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 28, 2017, 04:12:41 pm
Yeah, looks nice, but only 10kHz? Might as well get one of these:

For $21, DSO150 (https://www.aliexpress.com/item/Fully-Assembled-Orignal-Tech-DS0150-15001K-DSO-SHELL-DSO150-DIY-Digital-Oscilloscope-Kit-With-Housing-case/32826373665.html), nice enclosure, assembled, 200kHz. Pair it with a nice, safe, DMM.

Or for $46, get a DSO-112A (https://www.aliexpress.com/item/DSO-112A-TFT-Mini-Digital-Oscilloscope-Touch-Screen-Portable-USB-Oscilloscope-Interface-2MHz-5Msps/32629013364.html),  2 MHz, 5 Msps.

I've seen a few of these used in videos.   They seem to require an external power source.  Maybe someone makes a case with a battery pack for it.  Then is still is a scope, not a multi-meter.   The UT81 was a bit faster.  When I  was looking for small scope, I thought about getting one but did not see anyone say it was a good investment. 

I started a thread on the old  Flukes.  They can't read current or temperature directly and there is no capacitance mode. 

https://www.eevblog.com/forum/testgear/old-philips-fluke-97/ (https://www.eevblog.com/forum/testgear/old-philips-fluke-97/)

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 28, 2017, 05:54:01 pm
Yeah, it was just in response to the comments that the ET201 is only 10kHz and rather inadequate as a DMM. So, if a single instrument isn't a deal-breaking requirement, for not much more money, one might be able to do better with separate handhelds for DMM and scope.

The DSO112A has a built-in rechargeable battery. I think I saw it in operation on Marco Reps channel. I'm not that keen on having a touch screen, but the device seemed to show wiggly lines OK. ;D

Anyway, back to the combo handheld scopemeters.
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on October 28, 2017, 07:00:29 pm
There is also Velleman WFS210 for 20 quids discussed in https://www.eevblog.com/forum/testgear/vellerman-wfs210-wireless-oscilloscope-for-only-20- (https://www.eevblog.com/forum/testgear/vellerman-wfs210-wireless-oscilloscope-for-only-20-)!/ . It's a battery-powered portable wifi oscilloscope. Software seems to be crap, I haven't decided if I want it to buy or not.

For isolated measurements I use my MicSig TO1104, but 1) sometimes I forget to disconnect power 2) it's my main scope, I need one more isolated from it (preferably a tiny device as my bench is small). That's why I asked about options. Also, measurements on the scopes I've seen are imprecise. I mean, I know there is only 8bit ADC, but looks like I get even less steps, even with averaging (firmware issue?).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 30, 2017, 04:31:22 pm
CEM offers an AT-9996 automotive scope meter.  They also have the AT-9995 which  is a 4000 count.  Tach will work with 2-10 cylinder engines.  The dwell supports 2,5,6 & 8 cylinder engines.   

Mastech has a MS6230, 2000 count.

Someone did show the internals of the BM-319s with some sort of review.
https://www.eevblog.com/forum/testgear/brymen-bm319s-automotive-dmm-teardown-small-review-tme-supplier-feedback/ (https://www.eevblog.com/forum/testgear/brymen-bm319s-automotive-dmm-teardown-small-review-tme-supplier-feedback/)

Of the ones I have seen, I am leaning towards the CEMs and the Brymen.   CEM does not appear to have the manuals available.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on October 31, 2017, 12:36:09 pm
Joe
How would you feel about doing a tour of your lab and,or your Fluke calibrator ?

3DB
 :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 31, 2017, 04:27:58 pm
Joe
How would you feel about doing a tour of your lab and,or your Fluke calibrator ?

3DB
 :)

I have a old Fluke 731B reference standard that I show in several videos.  Besides that, I am not sure what you are referring to.  Most of the equipment has been used in various videos.

I ended up picking up an automotive meter to play with.   Don't expect me to unbox it and talk about how great it is for an hour. 
https://youtu.be/q_89qoFMivg
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 31, 2017, 06:05:41 pm
Joe, good tests - thanks for sharing. At first glance I could confuse it with a Hioki - it has a somewhat close appearance.

The display susceptibility to high voltage could be a coupling between the input terminals and the Holtek IC - they are physically close. As you mentioned, the fact the buttons still beep is revealing the main chipset is still going its merry way - further apart from the input terminals. 

The susceptibility to RF/interference is quite bad as well... I would expect automotive meters to be fully wrapped in shielding.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 31, 2017, 10:30:00 pm
Towards the very end, you may have noticed with nothing connected to the meter it would reset.   If you have worked on problems like this, you are aware it may have nothing to do with the inputs.   Maybe they will make a better version down the road. 

After seeing the BM235 reset, I am not sure about their automotive products.  In the manual they spec 3V/m.  That's nothing.   

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 31, 2017, 11:01:27 pm
Don't expect me to unbox it and talk about how great it is for an hour. 

Oh, thank goodness. :phew:
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 31, 2017, 11:38:08 pm
No worries. I knew you wouldn't suddenly change your style. :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on October 31, 2017, 11:40:08 pm
This was an excellent video and a good reminder to people that these types of products can be susceptible to all kinds of external influences. As no real destructive tests were conducted you should probably box this one back up and either make a claim or send it back because it was not as described, If you don't then the seller will not get the message that this practice as well as the meter itself is completely out of order.   >:(

Many thanks for your great efforts, it reminded me of how much I now miss my Suzuki, on a side note a mate came around once and saw that I had one and said "I didn't know you were into bikes", I replied "I'm not really, just hospitals and nurses".   :) 
Title: Re: Handheld meter electrical robustness testing.
Post by: xcube on November 01, 2017, 02:16:57 pm
CEM offers an AT-9996 automotive scope meter.  They also have the AT-9995 which  is a 4000 count.  Tach will work with 2-10 cylinder engines.  The dwell supports 2,5,6 & 8 cylinder engines.   

....

Of the ones I have seen, I am leaning towards the CEMs and the Brymen.   CEM does not appear to have the manuals available.   

CEM AT-9995 (http://cem-instruments.de/products/pkw-lkw-multimeter-4000-counts-mit-usb-cem-at-9995/) :
Manual (http://cem-instruments.de/wp-content/uploads/2014/09/DT-9995-Bedienungsanleitung-eng.pdf)

There are some more from CEM

CEM AT-9955 (http://cem-instruments.de/products/motortester-kfz-pkw-multimeter-cem-at-9955/):
Manual (http://cem-instruments.de/wp-content/uploads/2014/09/9955-Bedienungsanleitung-Eng.pdf)

CEM AT-9906DIS (http://cem-instruments.de/products/kfz-multimeter-motortester-tachometer-cem-at-9906dis/):
Manual (http://cem-instruments.de/wp-content/uploads/2016/10/DT-9906DIS-Bedienungsanleitung-DE.pdf)

Nice review on ALL-SUN EM135 Digital Automotive Meter, many thanks for this.

After seeing the BM235 reset, I am not sure about their automotive products.   

I have a quick look at the teardown picture form BM235, BM257 and BM319.
It seems to me that BM31x will based on BM25x and have a little more shielding when a BM235.
But only your tests will show if it is true.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 01, 2017, 06:54:10 pm
Joe, that engine emulator is awesome!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 02, 2017, 12:20:39 am
I suspect the RPM with the Brymens would be limited to 10K in this application.  The were very responsive as usual.   I ended up providing them the link to the video starting where I had the 869s on the jig.  They can at least watch their little meter reset.   lol.  I may get one but like the Fluke people have been pointing out.  Wonder if it would die like the 87V. 

Joe, that engine emulator is awesome!
Thanks.  These little projects are what makes electronics such a fun hobby. There is always so many things to learn.  People who are bored with electronics as a hobby must have a really limited skill set.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on November 02, 2017, 12:55:31 am
I suspect the RPM with the Brymens would be limited to 10K in this application. 
Which isn't of much use if you want to tune a chainsaw. <sigh>

There's not much decent available for high RPM engines other than a genuine Husky tacho, but the $$.  ::)
http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Husqvarna-502-71-14-01-OEM-Pulse-Engine-Tachometer-502711401.axd (http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Husqvarna-502-71-14-01-OEM-Pulse-Engine-Tachometer-502711401.axd)

Still, I guess they're are cheaper than these that we used 40 years ago:  ::)
http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Oregon-Wireless-Tachometer.axd (http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Oregon-Wireless-Tachometer.axd)


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 02, 2017, 01:38:03 am
Looks like they may not have read the datasheet.  I think the meter's susceptibility could be improved with some very minor changes.  If I can get it to survive some basic levels without a shield, I'll look into changing the front end.   
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on November 02, 2017, 01:47:41 am
I suspect the RPM with the Brymens would be limited to 10K in this application. 
Which isn't of much use if you want to tune a chainsaw. <sigh>

There's not much decent available for high RPM engines other than a genuine Husky tacho, but the $$.  ::)
http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Husqvarna-502-71-14-01-OEM-Pulse-Engine-Tachometer-502711401.axd (http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Husqvarna-502-71-14-01-OEM-Pulse-Engine-Tachometer-502711401.axd)

Still, I guess they're are cheaper than these that we used 40 years ago:  ::)
http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Oregon-Wireless-Tachometer.axd (http://www.baileysonline.com/Chainsaw-Parts/Repair-Tools/Tachometers-Ammeter/Oregon-Wireless-Tachometer.axd)
I shift around 10,500 and go through over 11,000 running 160MPH or so.   Not to say that chainsaws are not fun.  They most certainly are!!
Nice. We've chatted about drags some time back.

How long have you had the logging Joe ?
BTW, the column for Nitrous is blank.... WTF.  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 02, 2017, 04:44:32 am
People who are bored with electronics as a hobby must have a really limited skill set.

Yeah, same goes for those who say they're bored because they're retired. Having to work for a living is my limiting factor!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 03, 2017, 01:53:02 am
We don't all reach for the foil to solve every EMI problem.   

https://youtu.be/uuaRUWcrZRk
Title: Re: Handheld meter electrical robustness testing.
Post by: Crumble on November 03, 2017, 10:58:40 am
I may be a rare breed but I love working far too much to retire.  One day that may change.
I love that attitude. However, personally I find that when I'm not working I do tend to loose focus on what to do and how to do it and progress gets slower. I respect you for keeping on doing your thing and doing it thoroughly, keep it up! :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 04, 2017, 12:16:58 am
I added a few MOVs along with some resistors, similar to all the other meters I have looked at the hold up.  I hadn't thought about the fuse when I made the video and talked about cutting the trace and moving it.  This meter detects a blown or missing fuse with this circuit.   So I left it.   

Using a spare plug, then wrapped the inductive pickup's cable around the wire and ran it like this for about 15 minutes without a reset and the RPM is stable (as long as the RPM is high enough to disable the multi-spark).   The OEM inductive pickup that was left out of the box when I received it, may not do as well as this Fluke clamp.

I've been asking Brymen about their 319s.  They have confirmed that while they support both 2 and 4 stroke engines but they only support 2-stroke wasted spark, not 4 like I run. So this will cut the RPM by half.  This meter is also a little more generic with a mV and uA range.  The bar graph updates 40 times/sec rather than at the normal display rate like the All-Sun.  It also has both a + and - trigger rather than just +.   Sadly, it does not appear to be TRMS.

They watched the video where I had the two Brymen's on the ignition jig and Dave's went through the reset.   It may be interesting to see how the BM319s would handle this.  The 319s is also marked for CAT III 600V.  None of this CAT II stuff.  So if I run one, I will transient test it as well (after I run all the other tests). 

If the 121GW is released with an open source, maybe we can role an automotive version of that meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 05, 2017, 09:06:45 pm
Testing the final mods to the ALLOSUN.  Nitrogen tank was almost empty but it had enough to provide some additional stress to the meter.   

https://youtu.be/Xk6mPHkxs1Y
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on November 06, 2017, 05:32:45 pm
Huge difference in EMI between resistance spark plug cables and plugs compared to solid copper-core.
I know some magneto nitro dragsters run all solid-core wire and murder to do any datalogging without interference. But they have a distributor too, which also radiates a lot of EMI.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 09, 2017, 12:21:54 pm
I have continued to look at ways to run some sort of life cycle testing on a few of the meter's rotary switches.  I want to have a better way to determine how the contacts are degrading rather than just a visual inspection. 

I have considered using a camera and just using the resistance mode but the meter all have different specs and may not even read down low enough to detect a problem.    Using an external meter to measure the meter under test's current source may be an option but again, as the meter's batteries degrade and such, it may not be good enough.   Another option I considered was using an external meter to measure the resistance of the switched current inputs.   The values used the mA ranges are somewhat of a standard.  The problem again is trying to measure sub ohms of change on possibly 100s of ohm of shunt.   

The problem being obviously there is no standard why to beyond just doing the measurement directly.  What I don't like about this is the meter will have to come apart and test point added to the board and again use an external meter to make the measurement.   

I setup a test like this using one of the meters I had damaged.  In the plot shown, the vertical is the resistance and the horizontal is the number of switch cycles.  Again, this was a damaged meter so I would hope we would not see this poor of results with this few cycles.   

Obviously, the plan will be to run this destructive test on new meters at some point but until I sort out the details there is not much reason to take this step.  Similar to running the transient tests early on, it took a while to sort out how to run them.  For those of you who have been around since the beginning, you may remember I start out running damaged meters for that testing as well.   I doubt I will look at very many meters.   
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on November 09, 2017, 01:10:48 pm
How bad is the result?

For a cheap meter I do not see it as that bad:
The mA range is usual located so you do not need to pass through it except when measuring A or mA. I.e. it will not see that many passes.
For the other ranges on the meter I would not expect a ohm or two in the range switch is a serious problem.

For the more expensive meters I hope the range switch will lasts considerable longer.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 09, 2017, 05:54:51 pm
How bad is the result?

For a cheap meter I do not see it as that bad:
The mA range is usual located so you do not need to pass through it except when measuring A or mA. I.e. it will not see that many passes.
For the other ranges on the meter I would not expect a ohm or two in the range switch is a serious problem.

For the more expensive meters I hope the range switch will lasts considerable longer.

The switch is commonly used to control the power to the meter.  Of the meters I purchased to run, two of them would not power up because of problems with the switch.   The switch may not just hard fail but instead start to become intermittent.  I have ran into this with some of my old meters.  As a matter of fact, when I first started working on the transient testing, one of the meters I tested was my old BK Precision which the switch was going bad on. 

I really have no idea if its a common problem with handheld meters or not. It's not really my objective to determine this.  Like the transient testing, I am really just looking at how the different meters compare against some standard way of testing them. 

As to how bad this particular switch is, it's really bad.   Your feeling that it is not so bad is partly my fault.  I have zoomed into the sub 2 ohms but the resistance is off the graph.   

The switch continues to cycle and these are up to date graphs with it zoomed out to 150 ohms and 10M.  The switch has started to open up at 3000 cycles.   In this case, I am calling one cycle switching from off to on then back to off.  The cycle rate is currently fixed  for one cycle every 2 seconds.   I am running it slower to minimize heat buildup. 

It is very possible that the meter would have had trouble powering up long before the switch started to go open.   And again, maybe this is good enough for many people.  And again, to be clear this is a damaged meter.  The data I have collected so far is really just to get an idea how to run the test, not to try and suggest a meter has a bad switch design or not. 
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on November 09, 2017, 06:21:38 pm
We are talking more than 2000 cycles before it fails, for occasionally usage that would last many years. For daily use it would probably not be acceptable.
I would not see the 2000 cycles as a problem for <$30 meters, but for >$100 meters I would like considerable more cycles.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 09, 2017, 06:36:43 pm
There were a few people who commented early on during the transient testing about how I should not be showing $50 meters in the same light as $200 meters.  When I finally do start running them, they will all still be treated the same. 

I am not sure what a good target number is.  I tossed out some thoughts when I started working on this project.  In the end, I plan to run them to failure and let each viewer decide for themselves. 

Even with a 2 second cycle, there is still some small amount of heat built up in the switch. 

Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on November 09, 2017, 07:21:52 pm
For a full time DMM user 5-10 On-Off cycles/day would not be unreasonable IMO.
Consider max and 200 days use/year and we might think for a 1 year warranty 2000 cycles is a fair amount.

Quality meters, you might expect 4000 cycles IMO but would they actually do it ?  :-//

Interesting test Joe.  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 09, 2017, 07:23:21 pm
With all the data in a spreadsheet, one can choose their budget range and see what performs to their requirements. Pre-defining price tiers is probably unnecessary unless you do summaries/round-ups to choose winners.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 09, 2017, 11:21:04 pm
Consider that some may actually use their meters in CAT III and IV environments.  If the parts are wearing, that material is going somewhere and it may not be in a place you want it.   :-//   

If the basic Fluke is around for 30 years, using your 2000 a year we are talking about 60,000 cycles.   It seems like if we really want to know how well meters like the Brymen are going to hold up long term under normal use conditions, this may be one indicator.   I think that BK I mentioned was about 13 years old when I retired it with a bad switch.     

I'm not sure what metrics I will place in the spreadsheet.  Maybe the starting resistance, cycles until contact reaches 1 ohm, cycles until contact reaches 10M.   That or I may just keep the data on the PC like I have done with the test leads so I can compare them directly as they are ran.   I am also thinking I would like to run all of them some number of cycles regardless if they open prematurely. 

Attached, our dead meter is now at over 25,000 cycles.   Notice how the contact resistance continues to loft around but it continues to stay below 2 ohms now. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 10, 2017, 12:30:20 am
most meters have grease on the switch-pads,
although if that gets contaminated with metal-dust it could maybe create an unexpected path.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 10, 2017, 01:08:25 am
most meters have grease on the switch-pads,
although if that gets contaminated with metal-dust it could maybe create an unexpected path.

I think I have looked at maybe 60 different meters now which I will give you is not much of a sample.  Most of these have not appeared to have any sort of lubrication on the contacts.  Looking through pictures, I can't even say it is related to cost.  Have you seen a lot of meter reviews where they had grease in them?  Just curious why our experience with seeing it is so different. 

I could see the grease trapping contaminates as you suggest, but it may also prevent it in the first place.  When I run the meters, they really don't get enough cycles on them to see any problems.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 10, 2017, 03:05:27 am
There are plenty of other meters around which do not incorporate a rotary selector switch and in turn the necessary lubrication, I'm not sure if you have tested any of these types of meters as yet, maybe you did and I simply missed it. Additionally there are also few other testers and devices about such as CCTV testers and the like which incorporate multimeter features and functionality and from what I have seen they generally do not carry CAT ratings at all, I'm not sure how good the protection is on these types of meters or how they would hold up to scrutiny.

A few of the button type meters listed on the page below in addition to some pictures of those other testers.
https://www.eevblog.com/forum/reviews/wanted-the-ultimate-multimeter-for-electricians-and-technicians/ (https://www.eevblog.com/forum/reviews/wanted-the-ultimate-multimeter-for-electricians-and-technicians/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 10, 2017, 03:51:44 am
There are plenty of other meters around which do not incorporate a rotary selector switch and in turn the necessary lubrication, I'm not sure if you have tested any of these types of meters as yet, maybe you did and I simply missed it. Additionally there are also few other testers and devices about such as CCTV testers and the like which incorporate multimeter features and functionality and from what I have seen they generally do not carry CAT ratings at all, I'm not sure how good the protection is on these types of meters or how they would hold up to scrutiny.

Please explain why you feel that it is necessary to add lubrication to rotary selector switches.  I am also curious why you feel the vast majority of meters I have looked at do not have lubrication.           

One of the very first meters I looked at did not have a rotary switch.  This was the only one I ever looked at like this.  I don't believe anyone has ever asked me to run another meter like this.  I suspect they are just not popular. 

At this time, I don't have any interest in looking at other equipment outside the basic CAT III 600V and up rated handheld meters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 10, 2017, 04:30:17 am
Please explain why you feel that it is necessary to add lubrication to rotary selector switches. 
I did not at any point state that lubrication was necessary and only referred to meters which incorporate a rotary selector and in turn lubrication which was the context of the prior posts, as you well know there are discussions on which lubricant is best suited for this application and if I remember correctly Fluke themselves recommend a particular product, I don't recall ever having to apply lubricant on any of my meters other than a slight smear of silicone grease to a Fluke 83 which was not working and in a bad way to start with anyway. The question I submitted was entirely in relation to button type meters and their robustness and nothing more than that, sorry if you interpreted my post in the wrong manner.

I am also curious why you feel the vast majority of meters I have looked at do not have lubrication.
I made no such suggestion, again with all due respect Joe I think you are reading too much into my post.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 10, 2017, 03:06:30 pm
i was the one mentioning lubrication.

you obviously opened more meters than me, so i assume it was just more common in the past - although there was a very fine layer of lube on an aneng 8002 i recently stripped.
i think it was done in the past to stop the copper contacts oxidising or to prevent tracking in damp enviroments.

these days meters arent expected to have such a long life i suspect.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on November 10, 2017, 07:59:40 pm
About the only place I would put a grease of sorts in a multimeter switch is on the detent balls, and the central shaft area, the contacts would probably be best left dry, as they hopefully are a thick selective gold plate running on a selectively plated wiping contact, and this is pretty corrosion resistant in any case. A lubricant on the plastic parts to keep them from wearing each other out is fine, but all switches aside from those designed to run in transformer oil are best left dry.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 01:13:02 am
I did not at any point state that lubrication was necessary ....

There are plenty of other meters around which do not incorporate a rotary selector switch and in turn the necessary lubrication,...


i was the one mentioning lubrication.

you obviously opened more meters than me, so i assume it was just more common in the past - although there was a very fine layer of lube on an aneng 8002 i recently stripped.
i think it was done in the past to stop the copper contacts oxidising or to prevent tracking in damp enviroments.

these days meters arent expected to have such a long life i suspect.
I had a ZT102 (AN8002) that had something on the contacts but it did not appear to be a lubrication.

Most of the old test equipment I have appears to use silver plating.  That old 70's IBM meter I recently rebuilt did not appear to have anything in the contacts, only the detent area.  I don't have any other old meters to compare it with.   I have seen a few new meters where they really put it on thick like this Victor pocket meter.   

I would guess if you took a pole, people buying Fluke brand today expect them to last as long as a Fluke they bought in the 80s.  I doubt you would find many who expect a Kasuntest ZT102 to last this same amount of time with the same usage.  I really have no idea about the switch life of these meters but I have seen a few posts where people have asked about the life of the Brymen BM869s.   

About the only place I would put a grease of sorts in a multimeter switch is on the detent balls, and the central shaft area, the contacts would probably be best left dry, as they hopefully are a thick selective gold plate running on a selectively plated wiping contact, and this is pretty corrosion resistant in any case. A lubricant on the plastic parts to keep them from wearing each other out is fine, but all switches aside from those designed to run in transformer oil are best left dry.

I tend to agree but I am not a metallurgist or a lubrication / switch expert.  As Mutley mentioned, Fluke does call out what type of grease to use in some of their meters.   I have no plans to try and investigate the merits of using one type over another or dry vs lubed.  It would seem like the manufacture's would have studied this but there may not be any published papers on it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 11, 2017, 01:23:55 am
How does the grease affect conductivity? I have absolutely no idea about contact lubrication. I heard that potentiometers also have it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 02:04:51 am
I have seen a few pots with some sort of lubrication but again, it seems rare from my experience.   I have seen it in a WW pots but I don't think I have seen it in any other types. 

If the grease used were a good conductor, you can imagine the havoc it would play in a meter.  Then again, if it prevents wear it may help in the long run.  Then again, the switch designer may need the bit of friction to keep the contacts clean...  I have no idea.   

When I do start cycle testing the switches, I plan to take some before and after pictures.  This should give people some idea on how much grease, if any was used.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 08:57:44 am
I have completed my initial testing.  The external meter (HP34401A) is measuring the contact resistance using two wires that I soldered to the back side of the board, more than an inch away from the contacts to ensure that they were not disturbed during the setup.   This first curve, you can see the vertical is resistance and horizontal is the number of cycles.  I was planning to run the switch until it was a full open but I was getting close to 60,000 cycles and decided to end the test.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 09:01:40 am
This next curve, I am zoomed in to 10 ohms to give you a better idea how the contact resistance is changing.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 09:04:24 am
This is looking at a histogram (or distribution) of the resistance from 0 to 5 ohms.   Note that we really would expect this to have a tail as the contacts wear.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 09:11:40 am
Overall, the contact areas look pretty good.  There are some metal particulates but the vast majority is made up of the solder mask.   I zoomed into one pad to give you an idea how the very edge of the pads is wearing. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 09:23:51 am
I made an attempt to change the light to give you a better idea of the wear.   The wiper and pads both look really good for 50+ thousand cycles.  This switch would need cleaning but I see no reason it would not last for several years with heavy use.   

The next step is to finally run a working meter.  I plan to start with something low end and see what we can learn from that. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 09:30:09 am
One last picture showing a close up of the groove being cut into the mask.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2017, 07:38:21 pm
It appears that this contact may have started to wear through.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 12, 2017, 05:35:39 am
I made an attempt to change the light to give you a better idea of the wear.   The wiper and pads both look really good for 50+ thousand cycles.

That they do. I wouldn't have thought it had endured that much.

It appears that this contact may have started to wear through.

Reminds me of tire chains.
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on November 12, 2017, 06:28:56 am
Thickness of plating shows up there Joe, thin plating and a thin brass backing wears faster. I have seen old equipment with a nice gold flashed heavy plate, must have cost at least $1 for that amount of selective plated gold on there, onto a nice German silver button, which in turn was brazes to a springy Beryllium copper spring member, running on another similar button. Of course these were aircraft switches, meant to be used for either heavy current, thus the german silver buttons, or for signal use, thus the heavy gold plate. They were specced for current down to 5mA and with a 20A maximum limit, either 28VDC or 115VAC. Not sure of how much they cost when new, but these not only had a lot number on them, in addition to the manufacturers part number, but also had serial numbers as well, plus a Made in France at the bottom.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 12, 2017, 08:13:21 pm
that's not good,
i would have expeced the outer part to have low friction because of the balls pressing it apart.
if that had been on the inside - i would understand.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 12, 2017, 08:29:49 pm
It could be coming from the inside.   It's hard to tell at this stage.  Like the test run, I don't plan to disturb the setup until it is finished.   

When I ran the damaged Kasuntest, it was very clear that designers need to consider how to run the traces out of the switch as the contacts can cut through the solder mask and through the trace.  Like every test I run, I suspect we are going to learn something from this free meter as well.   

Is the Brymen really going to come up short compared with the Flukes like people claim..... It's coming...   :box: 
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 12, 2017, 09:13:47 pm
It'd be interesting to put a meter in a climate chamber and do some thermal cycling or 85°C/85%RH testing on it before testing the switch, that way it might corrode quite badly, which would certainly affect the reliability.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 12, 2017, 09:18:06 pm
Our first working meter is not holding up very well.

Those cheap little HF meters have a very poor selector switch. They oxidize and show poor continuity after the meter has sat in storage for a while. I have sometimes picked one up to use and found it reading way off. The cure was to turn the switch a few times to clean off the oxidation and re-polish the contacts.

(This may be a reason why so few meters have a separate on/off switch. Putting the on/off switch on the rotary dial forces you to turn the dial before use and that keeps the contacts clean.)

As for the plastic dust, I'm sure it is the inevitable result of soft cheap plastic and continuous abrasion from turning the dial. The meter wasn't meant to take that abuse.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 12, 2017, 10:10:57 pm
I doubt I will do anything with the environment.  Not that it's a bad to look at salt, temp, humidity, thermal shock..... but it would require far more resources than I am willing to commit.  It may also be interesting to look at different lubrications, materials, thicknesses...  I am not trying to predict MTBF numbers for the designs rather I just want to know how they compare when ran to common set of rules.       

To cycle a meter will require a few days and I doubt we will see much of an effect from the changing environment.   The plan is to inspect the switch prior to attaching the test points and again after the meter is ran.   From this, along with the resistance, we should get a pretty good idea how the various meters compare with one another.   I am betting on there being a significant difference in them but again, I don't know.     

Like the transient tests, I'm sure we will see all sorts of comments on why the test is invalid when it is all said and done.  When the Fluke 101 outperformed the Fluke 87V by a large margin, it brought people out of the woodwork.    :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 12, 2017, 10:25:33 pm
I doubt I will do anything with the environment.  Not that it's a bad to look at salt, temp, humidity, thermal shock..... but it would require far more resources than I am willing to commit.  It may also be interesting to look at different lubrications, materials, thicknesses...  I am not trying to predict MTBF numbers for the designs rather I just want to know how they compare when ran to common set of rules.       

To cycle a meter will require a few days and I doubt we will see much of an effect from the changing environment.   The plan is to inspect the switch prior to attaching the test points and again after the meter is ran.   From this, along with the resistance, we should get a pretty good idea how the various meters compare with one another.   I am betting on there being a significant difference in them but again, I don't know.     

Like the transient tests, I'm sure we will see all sorts of comments on why the test is invalid when it is all said and done.  When the Fluke 101 outperformed the Fluke 87V by a large margin, it brought people out of the woodwork.    :-DD   

Heheh, people are never happy with testing! I got complaints that I tested a consumer oriented technology demonstrator using Mil. Std. 833 tests instead of bothering with the consumer test standards. But it seemed quite pointless to repeat the same test over and over again, only to see nothing would happen. The funny bit was that it perfectly survived 1000 cycles of being dragged from -65°C to 125°C, but still they felt the need to complain. :)

But anyway, if you want I can buy a couple of cheap meters, abuse them, and send them over. It ain't much work for to toss them into the corner of a climate chamber at work, more than enough space. I'm mostly curious in how it would de-rate the protection on the board.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 12, 2017, 10:53:32 pm
Actually we might now that I think about it, I'll check tomorrow when I'm in the lab. Might also be able to just measure the resistance while it's in the climate chamber if a few channels on the system are open. That could be a rather interesting test if I go and give it a good twist every hundred cycles or so.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 12, 2017, 11:43:16 pm
I would welcome seeing more independent destructive tests being ran on handhelds.   
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 13, 2017, 07:57:54 pm
I would welcome seeing more independent destructive tests being ran on handhelds.   

Mhhh, we have a Chroma Hipot tester hanging around the lab and a safety cabinet for it as well apparently, 6 kV DC with a 10 mA trip current, and 5 kV AC with 30 mA trip current. Seems to cut out when it detects arcing though, so probably won't be very destructive on decent meters. I'll have to run by the health & safety person to get the key to this one I fear, but I'll give it a go.  :)

Could also already simply check the drift on its accuracy when exposed to those conditions. Can't imagine it'll do wonders on low-end meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 13, 2017, 11:46:29 pm
Drift would be a good one to look at.   I don't recommend switch cycling.  The Kasuntest continues squeaking.   
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 13, 2017, 11:51:47 pm
what is the test?

fixed number of cycles?
fixed number of hours?
cycle till the switch falls apart?  :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 14, 2017, 03:10:35 am
what is the test?

fixed number of cycles?
fixed number of hours?
cycle till the switch falls apart?  :-DMM

Inspect
Remove batteries as they are not used for this test.  Very carefully take meter apart as to not disturb contact area.  Document the switch area with a camera and note any lubrication.

Prep
Select contact and locate places where 30 AWG solid core wire may be attached at least one inch from switch to avoid any possible damage to switch pads.    Using about 6" of wire per test point.   Route wires outside of case without placing any strain on the case.  I have been going through the battery cover. 

Pretest
Attach external meter and measure the DCR with the switch closed.   Select which fork to use based on selector switch size.  Determine where to program the stepper to allow the function switch to fully rotate.   

Cycle
The switch is fully rotated both directions to complete one cycle.  Each switch will be cycled 50,000 times.  Note, if they are intermittent, I will continue to cycle them but if they go full open (1000 cycles with no resistance), I will abort the test.  If they grind to dust, I will continue the test as long as the switch continues to have some measureable resistance when closed.   

Final Inspection
Once the meters have been cycles, I will disassemble them and document my findings.  I plan to use the microscope to capture the problem areas.  I am interested in metal particulates trapped between the contacts and cut traces more than anything as these could pose a risk.   At this time, I have no plans to incrementally pull the meter down for inspection prior to fully completing the cycle test to avoid any contamination to the test.   

The software obviously records the contact resistance and I have a few different metrics that I plan to use to show how each switch wears. 

************************

This is a VERY LONG and time consuming test to run.  We are measuring fairly low resistance so the meter takes time to settle and you can't cycle the switch so fast that the plastic starts to warp or melt.  So it's the slow easy pace.

I wonder if the 17B+ will be useable after this many cycles.....
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 14, 2017, 06:28:26 am
Drift would be a good one to look at.   I don't recommend switch cycling.  The Kasuntest continues squeaking.

Drift testing would be easy enough. It's safe to presume that a calibrated Keithley 2001 is a good enough reference to work against. First victim has just been ordered: https:// m.aliexpress.com/s/item/32818141467.html

Heh I can imagine so. Try MIL-833 thermal shock for electronic assemblies, you could do it at home fairly quickly actually. Only issue is that it'd annihilate the LCD in these things most likrly.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 14, 2017, 12:46:42 pm
Your link did not work but item 32818141467 appears to be the UNI-T UT136B.   With as many UNI-T products I ran, I have never looked at this one. 

I have thought about making a small cooler for my cardboard/foam meat packing box.  This will be for fixed temperature testing.  I've ran some drift tests for people in the past where I set the box to an elevated temperature and hold it.   It would be nice to be able to run a sweep with it.  I have not thought about running any sort of controlled shock test.  Building some sort of dumbwaiter chamber would take far more effort than I would be willing to invest in a test like this.   

Good look testing.  As always, it will be interesting to see what you come up with.   


The Fluke was the forth meter I have attempted to measure the contact resistance with while life cycling the switch.  It has a long road ahead of it but I will say that the preliminary results are impressive.  Then again, it's being compared with a free meter, the ZT102/AN8002 and a blown up POS.   :-DD   

My wife said I can't life cycle the original Fluke 101 I bought because it would be just wrong at this point.   :-DD :-DD  It has survived everything I have thrown at it but I am still thinking to do some sort of high voltage shootout with the surviving meters at some point. Cycle testing this meter may damage it.  50,000 cycles takes days at the rate I am cycling them takes days, so there is plenty of time to decide.       
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 14, 2017, 02:54:42 pm
My wife said I can't life cycle the original Fluke 101 I bought because it would be just wrong at this point.   :-DD

FWIW I agree. Do the 87V instead.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 14, 2017, 04:12:38 pm
My wife said I can't life cycle the original Fluke 101 I bought because it would be just wrong at this point.   :-DD
FWIW I agree. Do the 87V instead.
I am thinking about it.  87V fan boys have been commenting how well these meters hold up over time and question the life of the Brymen BM869s. 

Obviously, the old Schwinn bike has been around long enough to have some history compared with the new Giant with its Shimano shifters and Rigida rims.  We don't have a time machine, but we can accelerate the test.   If you want to take the personal fan boyism out of the equation, it only makes sense to grind the two meters into dust.   

Anyone want to loan me a brand new 87V to play with for a few days??  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on November 14, 2017, 04:48:43 pm
Anyone want to loan me a brand new 87V to play with for a few days??  :-DD

If it fails, then it's still under warranty, right?   After all, the "normal wear and tear" exclusion wouldn't apply because this wear and tear would be anything but "normal", right?   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 14, 2017, 05:11:12 pm
Anyone want to loan me a brand new 87V to play with for a few days??  :-DD
If it fails, then it's still under warranty, right?   After all, the "normal wear and tear" exclusion wouldn't apply because this wear and tear would be anything but "normal", right?   :-DD

I'd post it off to them just to see what they say.

50,000 turns isn't completely ridiculous though, eg. It's only 14 measurements a day for 10 years (assuming you switch on, measure, switch off). I bet a lot of people around here can beat that.

50,000 turns on something with a mid-2017 manufacture date,  I wonder if they'd spot it?  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 14, 2017, 05:15:51 pm
How about a Fluke 27 or something similar? From the days when rotary switches were made with real switches.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=370174;image)

Bonus: It goes round and round forever. None of this left and right rubbish.

It would be interesting to see how they hold up electrically, too. This is one of Flukes first "robust" meters.

"Rugged safety features include extensive overload protection, high energy fuses, fused 10A range, and non-metallic cases and tilt bail. All voltage inputs recover or fail safe under power line surge tests for major feeders. This includes simulated lightning and load switching transient pulses up to 8 kV."

http://www.fluke.com/fluke/m2en/digital-multimeters/fluke-27.htm?pid=56055 (http://www.fluke.com/fluke/m2en/digital-multimeters/fluke-27.htm?pid=56055)

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 14, 2017, 06:52:07 pm
that's a nice waferswitch.
unfortunatly experience with old scopes show they will fail - by tarnishing usually.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 14, 2017, 09:00:16 pm
Your link did not work but item 32818141467 appears to be the UNI-T UT136B.   With as many UNI-T products I ran, I have never looked at this one. 

I have thought about making a small cooler for my cardboard/foam meat packing box.  This will be for fixed temperature testing.  I've ran some drift tests for people in the past where I set the box to an elevated temperature and hold it.   It would be nice to be able to run a sweep with it.  I have not thought about running any sort of controlled shock test.  Building some sort of dumbwaiter chamber would take far more effort than I would be willing to invest in a test like this.   

Good look testing.  As always, it will be interesting to see what you come up with.   


The Fluke was the forth meter I have attempted to measure the contact resistance with while life cycling the switch.  It has a long road ahead of it but I will say that the preliminary results are impressive.  Then again, it's being compared with a free meter, the ZT102/AN8002 and a blown up POS.   :-DD   

My wife said I can't life cycle the original Fluke 101 I bought because it would be just wrong at this point.   :-DD :-DD  It has survived everything I have thrown at it but I am still thinking to do some sort of high voltage shootout with the surviving meters at some point. Cycle testing this meter may damage it.  50,000 cycles takes days at the rate I am cycling them takes days, so there is plenty of time to decide.     

Well, I'm not quite willing to put up my ancient Fluke 73 (still has the gray bumper case even :D ), or the newer Keysight one up for this sort of testing. So went on aliexpress instead for now, I'll scour eBay for some main brand ones later maybe.

I ended up buying these two to begin with:
https://www.aliexpress.com/item/UNI-T-UT136B-Digital-Multimeter-Auto-Range-Tester-AC-DC-Voltage-Current-Ohm-Diode-Cap-Hz/32818141467.html (https://www.aliexpress.com/item/UNI-T-UT136B-Digital-Multimeter-Auto-Range-Tester-AC-DC-Voltage-Current-Ohm-Diode-Cap-Hz/32818141467.html)
https://www.aliexpress.com/item/NEW-NK-51E-Multimeter-VS-UT136B-UT120C-MS8233D-With-2000uF-Capacitance-and-Frequncy-Measurement-Auto-Range/32757114149.html (https://www.aliexpress.com/item/NEW-NK-51E-Multimeter-VS-UT136B-UT120C-MS8233D-With-2000uF-Capacitance-and-Frequncy-Measurement-Auto-Range/32757114149.html)

The second I mostly wanted because it's pink, honestly who wouldn't want a pink multimeter! (Maybe we should all pitch in and buy one for Dave?)

Also have a couple of DT-830s hanging around that I've been meaning to blow up for months that I could include in the test. To be precise, I have an old capacitor bank laying around from an ill-advised railgun construction project ages ago, my main issue is that I can't find an affordable high voltage relay for it at the moment. Best one I could find on Farnell for a reasonable price arced internally, so planning to build my own transformer oil filled relay at one point or another.

But to get back to the subject at hand, the plan is to test the drift over the product lifetime by thermal cycling and ageing tests while I still have access to that climate chamber. After that I plan to just put them in water tight bags and expose them to some Belgian weather and see how long they last. Planning to verify drift and accuracy for voltage, current, diode, input impedance on volts, diode measurement current, and resistance measurements. For voltage, input impedance, and current I'll use a calibrated Keithley 2001 as reference. (If any of them would manage to go high input impedance I'll just pull out the 238 SMU and force the situation a bit :D ) For resistance I'll use some high precision wirewound resistors, and for diode I have some fun stuff laying around still that should be exceptionally stable.

Any remarks before I get started?  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 15, 2017, 12:16:55 am
Heheh, it's almost begging to be tested isn't it? But it's soooo pretty, I don't want to destroy it.  :-DD  I also love how they can't seem to decide on which batteries the thing uses, or how they show ceramic fuses next to it but never the portion of the PCB that contains said fuse. My money is on glass fuse with a cheap PTC in series. A MOV would certainly cost more than the 5 cents budget they had for the BOM.

Photonic Induction's cap is the real world equivalent from the average ACME weapon from Looney Tunes. But yeah, if you want to blow up meters, you got to do it properly! It'd also be fun to try to blow one up using induced currents when it's in ohms. (Make a coil out of copper tubing and discharge that cap bank through it.) I'm not quite sure what'd the use of that test would be, but I suppose it checks the resistance against externally induced electromagnetic noise?  :-DD

Actually we have a pile of UT61Es in the lab, we all bought them at the same time from the same supplier so it'd be funny to check if they still match up. These have seen a bit more (ab)use than yours I think considering the stupidity of some of my colleagues.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 15, 2017, 12:54:40 am
The pink would go nice with that florescent green TPI meter I have.  Who knows, maybe the pink one will do great compared with the others you look at.  I run into all sorts of unexpected results.   

Looking at my cheat card,  I started collecting data for the UT61E on 11-21-16.   Looking at it today, it appears it has not budged.  Must be all the dope I used on it.    If there is ever a contest for the most chopped up handheld meter, I may have to enter this one.   :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 15, 2017, 03:56:35 am
about ut61e drift,

i suspect it was only voltage and related to rough handling.
the older ones had a 2k multi-turn pot, those things can move inside if you bang them hard enough.
the latest ones have a 1k pot and some different fixed resistors so the pot covers a smaller range.
so newer ones should be a lot better.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 15, 2017, 04:18:39 am
The second I mostly wanted because it's pink, honestly who wouldn't want a pink multimeter! (Maybe we should all pitch in and buy one for Dave?)

Dave recommended that one in one of his videos (at the 1:07 mark):

https://www.youtube.com/watch?v=HicV3Z6XLFA&t=1m07s (https://www.youtube.com/watch?v=HicV3Z6XLFA&t=1m07s)

Maybe he owns one in secret.

Full disclosure: I actually own one, for the stated reason.

I also love how they can't seem to decide on which batteries the thing uses, or how they show ceramic fuses next to it but never the portion of the PCB that contains said fuse. My money is on glass fuse with a cheap PTC in series. A MOV would certainly cost more than the 5 cents budget they had for the BOM.

Nope, ceramic fuses. Followed by a PTC and some MELF resistors.

The pink would go nice with that florescent green TPI meter I have.  Who knows, maybe the pink one will do great compared with the others you look at.

In real life it's more purple than pink. I'm saving it for a "gothic workbench" video.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 15, 2017, 04:28:23 am
about ut61e drift,

i suspect it was only voltage and related to rough handling.
the older ones had a 2k multi-turn pot, those things can move inside if you bang them hard enough.
the latest ones have a 1k pot and some different fixed resistors so the pot covers a smaller range.
so newer ones should be a lot better.

Just to be clear for those that may read this and have not seen the videos where I chopped this meter to bits,  I had changed out the multi-turn trimmer in question when I had compensated the reference to a different value and brand.   

This is what not to do with your meter!     
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 15, 2017, 04:56:56 am
bourns - that wasnt cheap i'm sure.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 15, 2017, 01:32:05 pm
Next up: Testing the input jacks.

No, it's not a real proposal of course, but that is the most vulnerable part in some DT models (similar to the free meter you mentioned). I have one and that's the first thing that broke (not counting the probes), so I soldered the broken metal tab connecting the input jacks to the PCB together used some epoxy so that there is no strain on the metal tabs keeping things connected. It may or may not have lost some accuracy, but it still works decently for continuity checks and some quick (low) voltage checks.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 15, 2017, 04:24:14 pm
The Fluke 17B+ has surpassed the free HF meter in cycles and there are no signs of anything going on with the switch.   So I think we can hang our hats on the fact that Fluke has a more reliable switch design than the Cen-tech.   The first useful bit of info...  :-DD

There is still a long way to go before we reach Kasuntest cycles....
If this little Fluke is able to go to 50k, that would be quite a safe and sturdy meter...

My wife is warming up to the idea of running the little 101. 
If the 101 goes to 50k, that would be an unbeatable price/durability point. :)
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 15, 2017, 06:03:58 pm
Dave recommended that one in one of his videos (at the 1:07 mark):

https://www.youtube.com/watch?v=HicV3Z6XLFA&t=1m07s (https://www.youtube.com/watch?v=HicV3Z6XLFA&t=1m07s)

Maybe he owns one in secret.

Full disclosure: I actually own one, for the stated reason.
Question is, would this one be banned in Russia?

Nope, ceramic fuses. Followed by a PTC and some MELF resistors.
Mhhh, it'd be interesting to see how it holds up if that's the case. Might have to run it through some careless probing.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 16, 2017, 09:01:03 am
Quote
geonomad says:
July 17, 2017 at 3:07 am

The biggest problem I have had with the Chinese cheap meters has been the switch contacts.
If a reading appears wonky, I rotate the selector switch back and forth a few times to “clean”
the contacts and the readings come back to reasonable – sometimes. This is especially true if
the meter has been sitting in a drawer for a long time between uses.

I've been there too... Have you?

Yes.

I used to have a manual ranging meter that didn't work on the 20V range* without a bit of switch-jiggling. I eventually threw it out.

(*) ie. The range that gets used the most.

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 16, 2017, 09:22:13 am
Nope, ceramic fuses. Followed by a PTC and some MELF resistors.
Mhhh, it'd be interesting to see how it holds up if that's the case. Might have to run it through some careless probing.

I just dug it out to have a play using my new-found wisdom, gained on these forums.

It's not a great meter compared to this year's wave of ANENGs*, but it IS purple and would fit perfectly into a Hello Kitty themed workbench.

(*) Capacitance only goes down to 1uF, Ohms is slow, diode test can't light up an LED.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 16, 2017, 12:51:16 pm
Quote
geonomad says:
July 17, 2017 at 3:07 am

The biggest problem I have had with the Chinese cheap meters has been the switch contacts.
If a reading appears wonky, I rotate the selector switch back and forth a few times to “clean”
the contacts and the readings come back to reasonable – sometimes. This is especially true if
the meter has been sitting in a drawer for a long time between uses.

I've been there too... Have you?

Yes.

I used to have a manual ranging meter that didn't work on the 20V range* without a bit of switch-jiggling. I eventually threw it out.

(*) ie. The range that gets used the most.
Many times as well. A Uni-T UT55 (Triplett 9005) and older analog ones from Icel were always problematic.

This endurance test on the Fluke is more than enough evidence to completely obliterate an old suspicion of mine regards the durability of the "new" rotary switch versus the "old" ganged buttons of the older 80xx family.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 16, 2017, 06:21:00 pm
Nope, ceramic fuses. Followed by a PTC and some MELF resistors.
Mhhh, it'd be interesting to see how it holds up if that's the case. Might have to run it through some careless probing.

I just dug it out to have a play using my new-found wisdom, gained on these forums.

It's not a great meter compared to this year's wave of ANENGs*, but it IS purple and would fit perfectly into a Hello Kitty themed workbench.

(*) Capacitance only goes down to 1uF, Ohms is slow, diode test can't light up an LED.


Ah too bad, but we'll see how it fares. Planning to give it a run for its money in stability vs. a Weston cell reference  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2017, 04:22:12 am
It was getting a bit long so I decided against running a forth meter.   This should give viewers some idea how I plan to proceed.

Looking at new meters, I think as long as I don't run them on the half cycle simulator, the switches will be fine to life cycle. 

Should have the video uploaded today.  In the meantime, here is a picture showing a worn through contact.  Yes, it's basically a hollowed out square dragging over the PCB.  Stay tuned to see the damage...
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 17, 2017, 06:39:18 am
Wish we could measure the hardness on these.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2017, 01:08:05 pm
You could determine the hardness, thickness of plating and materials used for both the contact as well as the PCB.  It's only money and time.  I look at it no different than the lube/dry contact.  I use the products, not design them.

I can see one argument from this video.  Say a high quality meter cost $130 and the low quality meter was $10.    That's 13 cheap meters I could buy for the price of one.  Seems like a great deal ... but ... if the high quality meter last 50 X longer than the low quality one,  to do the same job is 50 X $10 or $500 operating cost.   Not to mention the down time, and collecting bad data...

Maybe there are mid range meters that will perform as well as higher cost ones over the long run.  In the mean time, feel free to watch the first few meters.   There are only a few short clips of them cycling.  I can speed up the transient test but the time required to run this test is on a new scale.   

https://youtu.be/x_L6Z8BAXFQ


Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 17, 2017, 06:09:08 pm
Useful results, but I think the argument for durability will depend on some factors.

If you're a professional, by all means you need a reliable durable meter and over time perhaps calibration for some work?

But as a beginner looking to do hobby electronics, unless you use the meter daily I believe even the cen-tech / DT800 series meters will last long enough, switch-wise.
That said, my first meter was about $10 and had issues with the range switch and probe contacts from the start, possibly just a bad unit, or maybe you will find meters that have less durable switches than even the free meter. Another weak point on some meters will be the probe inputs. These will definitely break faster on some meters than others.

Too bad you're not being paid for the tests.


Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 17, 2017, 06:23:20 pm
Useful results, but I think the argument for durability will depend on some factors.

If you're a professional, by all means you need a reliable durable meter and over time perhaps calibration for some work?

But as a beginner looking to do hobby electronics, unless you use the meter daily I believe even the cen-tech / DT800 series meters will last long enough, switch-wise.
That said, my first meter was about $10 and had issues with the range switch and probe contacts from the start, possibly just a bad unit, or maybe you will find meters that have less durable switches than even the free meter. Another weak point on some meters will be the probe inputs. These will definitely break faster on some meters than others.

Too bad you're not being paid for the tests.

At least spend the 20 bucks to get a uni-t or vichy vc97, or maybe that pinktacular thing I linked earlier. It ain't much more, but it will do fairly well compared to DT830s.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 17, 2017, 06:40:48 pm
I got an ANENG 860B+ in the end and I'm really happy with it. The min, max and rel functions are all very useful.

I still use the DT for quick checks such as continuity (it is the non latched type, but it's also instant as well), battery level, etc.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on November 18, 2017, 03:54:18 am
Before anyone beats me, congrats on passing 4K subscribers Joe! I enjoy your dedication sir.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 18, 2017, 04:06:29 am
You definitely beat me, Cliff.

Congrats, Joe! :clap:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 18, 2017, 04:19:53 am
It's been a while since I saw the inside of a Fluke 17B+, I'd forgotten how well made they are. All the input jacks, input protection, PCB layout, etc. are orders of magnitude better than those $15 meters that are so fashionable.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 18, 2017, 08:54:45 pm
Before anyone beats me, congrats on passing 4K subscribers Joe! I enjoy your dedication sir.
You definitely beat me, Cliff.

Congrats, Joe! :clap:
Thank you for your support.  The channel is larger now than I ever expected it to get.   I've certainly learned a lot about handheld meters in the process and hope others have as well.   

Most recently I would say we learned that quality meters don't put vias in the function switch pads and don't route traces
between the pads where they may be damaged by the rotating contact.  Seem obvious afterwards.   

I'm sure I have upset countless people over the last few years presenting all this data.  A lot of meters were destroyed in the process and nobody likes seeing their meter fail.   

From my own perspective, I continue to look at them out of my own interest.  To be clear, I have no axe to grind with any company as some suggest.  Well, again I fully admit I was biased against Fluke from the start.  Damn you Fluke for making such robust products....   :-DD   I still have no plans to use patreon or enable ads.  I appreciate those of you who have asked about sending me meters to run and such.  I have still not looked into a PO box.  The problem is really the lack of time to run them.   For those of you wanting to support the channel, your views and feedback are more than enough. 
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 19, 2017, 01:07:46 am
Well, again I fully admit I was biased against Fluke from the start.  Damn you Fluke for making such robust products....

I think we'll only be sad if your Fluke 189 has displaced your BM869s as your go-to meter on the bench. For me, mainly because the 189 was discontinued shortly before I wanted to get one. So damn you Fluke for discontinuing the best meter you ever made...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 01:47:00 am
Well, again I fully admit I was biased against Fluke from the start.  Damn you Fluke for making such robust products....

I think we'll only be sad if your Fluke 189 has displaced your BM869s as your go-to meter on the bench. For me, mainly because the 189 was discontinued shortly before I wanted to get one. So damn you Fluke for discontinuing the best meter you ever made...
The Fluke is a very nice meter considering it's age.  It actually does get some use on the bench.  The Brymen BM869s is still king as far as I am concerned.  It's just an all around good meter for electronics.  One day I am sure I will find something I like better.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:23:48 am
There is some confusion about the data I show.  Lets start with the four data sets zoomed from 0 to 1 ohm for all 50,000 cycles.  These are absolute values.  The Centech meter drops to 0 at 17,000 where I abort the test. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:30:22 am
Now let's look at the histograms for all four data sets again looking at the same 0 to 1 ohm span.   Let's start with a 1000 bins.    On the far left, the Centech blows off the chart at 0 because I aborted the test.   It seems the confusion is how the Fluke is such a small peak compared with the other data sets.  As I have said, that Flukes standard deviation is very low compared with the other meters.  For me it looks normal but I can fully understand the confusion. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:33:04 am
So let's increase the number of bins from 1000 to 2000.  Notice I have changed the vertical scale of the graph as the peaks are now shorter and wider.  Also notice how the ratio of the peak heights have changed.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:35:17 am
Let's go to 4000 bins.  Again I have rescaled the vertical axis.  The peak height of the Kasuntest and Fluke are now very close with one another.  But you can clearly see the Kasuntest is a much wider peak. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:42:51 am
Let go even further to 8000 bins.  Now we see the peak height for the Kasuntest is much lower than the Fluke.   I have zoomed into the horizontal axis to look at the data from 0.3 to 0.6 ohms to provide you with a better idea of what the peak shapes look like.  Not the Centech is there but the resistance is so high there is not much data in this area. 

So to be clear the bin size effects every data set. 
Title: Re: Handheld meter electrical robustness testing.
Post by: max666 on November 19, 2017, 03:48:24 am
The problem I'm still having with the Histograms is that the sum of all the bins, or if you will the area under the curve should be equal the number of samples. So for the Fluke it should be 50 000 also for the Kasuntest and the Baseline, only the CenTech should have a lower total. Since the Fluke has such a low standard deviation it's peak should be much higher to get to the same total of 50 000. Maybe my eyes are deceiving me, and it's just me.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:53:19 am
There is also some confusion about the log/log graph.   Again, this graph shows how many cycles until the switches resistance changes by more than a given amount.  The graph shows only the data from 0.005 ohms to 500 ohms for the 50,000 cycles.   So in the case of the Fluke, even with 5mOhms the switch never changed that much in the 50,000 cycles.  This is why it's a flat line.   Now the person asking feels there should be a vertical line going up to the 50,000 but because I am not looking for changes less than 5mOhms, we never see this.   Basically this was because I didn't care about changes this small.  I actually started out just looking at 50mOhms but thought may people would want to see what was happening down in the muck.  The Centech and nameless POS meter both reached 20mOhms right from the start. 
Title: Re: Handheld meter electrical robustness testing.
Post by: max666 on November 19, 2017, 03:55:00 am
And for the Log-Log, yes primary issue for me is that you start plotting from 0.005 Ohm, where as that is already the maximum for the Fluke.
But also I wouldn't continue drawing the horizontal line (at least for the Fluke) after 0.005 Ohm, since the Fluke didn't fail at 50 000 Cycles and didn't actually show a change in resistance of 500 Ohm at 50 000 Cycles.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 03:57:49 am
The problem I'm still having with the Histograms is that the sum of all the bins, or if you will the area under the curve should be equal the number of samples. So for the Fluke it should be 50 000 also for the Kasuntest and the Baseline, only the CenTech should have a lower total. Since the Fluke has such a low standard deviation it's peak should be much higher to get to the same total of 50 000. Maybe my eyes are deceiving me, and it's just me.

No problem.  I want to try and help you understand what you are looking at.  The screen itself has a limited resolution as well.  If we continue to push it so the Fluke filled the screen you would see that those bins are pretty narrow and they all have a lot of data in them.  This will not be the case with the others.  However, part of the problem here may be that you are not actually seeing the bins.  I am drawing a line connecting the peak of each bin which can certainly give a different impression.
Title: Re: Handheld meter electrical robustness testing.
Post by: max666 on November 19, 2017, 04:04:14 am
The problem I'm still having with the Histograms is that the sum of all the bins, or if you will the area under the curve should be equal the number of samples. So for the Fluke it should be 50 000 also for the Kasuntest and the Baseline, only the CenTech should have a lower total. Since the Fluke has such a low standard deviation it's peak should be much higher to get to the same total of 50 000. Maybe my eyes are deceiving me, and it's just me.

No problem.  I want to try and help you understand what you are looking at.  The screen itself has a limited resolution as well.  If we continue to push it so the Fluke filled the screen you would see that those bins are pretty narrow and they all have a lot of data in them.  This will not be the case with the others.  However, part of the problem here may be that you are not actually seeing the bins.  I am drawing a line connecting the peak of each bin which can certainly give a different impression.

That's probably it!
Thank you for being so patient with me, Joe.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 04:10:51 am
And for the Log-Log, yes primary issue for me is that you start plotting from 0.005 Ohm, where as that is already the maximum for the Fluke.
But also I wouldn't continue drawing the horizontal line (at least for the Fluke) after 0.005 Ohm, since the Fluke didn't fail at 50 000 Cycles and didn't actually show a change in resistance of 500 Ohm at 50 000 Cycles.

I figured this was the problem.  So for fun let's push things down even lower into the muck by a factor of 10.   Now we can clearly see there is a limit that we detect some change with the Fluke.   

Now it becomes a question of how good is good enough.  Someone had made the point earlier about how it's a high impedance input and tens of ohms may not be much of a problem except when you start looking at the current input.   I really am not sure that I want 10s of ohms for the power selection as well.   

Anyway, hope some of this helped clear things up.  I can certainly understand that how I view the data may not be the way that you or others would want to see it formatted. 

I did see the post about show them as a percentage which I just plain did not get where they were coming from.  I did respond to them the best I could.  It is difficult at times to know what the person is asking and if I am even addressing their concerns.     

Quote
As far as I understand is that you're using the absolute resistance value? If so, than you're not comparing apples with apples. You need to compare the change in value relative to the original start resistance, since the resistance of the tracks/circuits etc of the different meters isn't identical. In software this can easily being done by reading the first value and divide the other readings by the value to get the correct relative value. So this will give you a ratio (or percentage) how much off the meter is after x-amount of cycles.

Quote
You understand correct.  While we could plot the resistance as a percentage change,  I don't feel it is something I "need" to do nor do I see any value in displaying the data this way as it tells me nothing.  It could also make a very poor performance switch appear better than it is.

Let's take a simple example using two switches A&B.   Switch A has a DCR of 0.001 ohms.   Switch B has a DCR of 10 ohm.   Switch A say reaches a peak resistance of 0.010 ohms,  while switch B reaches a peak of 20 ohms.   Switch A has an increase of 10X and switch B, 2X.   Looking at a percentage would present Switch B as the better of the two. 

You are also correct in there there are other errors outside the switch contacts.  For the most part, these will remain a constant throughout the test for a given meter.  They make up a small portion of the total resistance.  We are basically talking about the trace lengths from the pads to where the wires are attached, the solder joint and the wires going back to the external meter.   These wires for the most part are a constant from meter to meter.  The same for the solder joint.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 19, 2017, 04:26:18 am
I wanted to see of there was by some chance of luck that the Kasuntest would have outperformed the Fluke down in the noise floor.  Looking at the log/log from 0.00005 ohms to 500.   Really pointless with the test setup I am using but here it is anyway.

Title: Re: Handheld meter electrical robustness testing.
Post by: max666 on November 19, 2017, 05:14:15 am
...
Anyway, hope some of this helped clear things up.  I can certainly understand that how I view the data may not be the way that you or others would want to see it formatted. 
...

It certainly helped. And I don't expect this to be a musical request programme, but just to exhaust one more possibilities on how to present the data  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2017, 12:13:55 am
Attached is the picture I show in the last video of one of the ZT102 contacts.  The tip of the wiper had wore through and we ended up with a hollow sort of square.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2017, 12:28:38 am
I have an old 60's Olympus microscope that I made a custom mount for and it is set on a machinist base.  A real nightmare to look at.  It's decent for working on small circuit boards with a 10-40X zoom.    Shown looking at a 0.01mm/div alignment slide.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2017, 12:33:54 am
I had some lenses as decided to see if I could get some better pictures of the ZT102's contacts.   Tp sort out the focal point, prototyped it with cardboard, paper and masking tape.   

Here are a couple of shots using different lenses.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2017, 12:37:57 am
It's way too touchy and sensitive to the depth to get a good picture.  But you can clearly see the holes going through the contact.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2017, 12:50:26 am
Here is with the contact removed and then backlit with and without the top illuminator.   
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on November 20, 2017, 01:34:31 am
It's the rotary switch wipers wearing out? I thought the PCB copper would wear out first, it's surely 1oz (1.4mil) or less.
I guess for low contact resistance, they (cheap chinese DMMs) apply a lot of force - instead of using precision multi-fingers.

Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on November 20, 2017, 04:46:15 am
For the ZT-102 it looks like the FR-4 wear generates abrasive (fibreglass dust) and that pretty much quickly kills all metal in the rotary switch.

Many potentiometers, they use three fingers. So you have extra width on the track and 1/3 the contact force over the same contact area. I'm not sure of the relationship between resistance and contact force. I suppose they could do this for multimeters, use multiple fingers and lighter contact pressure. pic from http://www.ladyada.net/wiki/tutorials/learn/arduino/leds.html (http://www.ladyada.net/wiki/tutorials/learn/arduino/leds.html)

Wavetek/Beckman multimeters (HD110, TECH300, 3030 etc.) don't use a wiper, the knob is a rotary cam pressing on many (16!) stationary switches. pic from http://mrmodemhead.com/blog/beckman-industrial-hd110-multimeter (http://mrmodemhead.com/blog/beckman-industrial-hd110-multimeter)
These were not super reliable, the switches got a bit bent up somehow under normal use, and not all had gold plating. I've repaired several bending the arms to align them.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 20, 2017, 06:31:18 am
Might not know much, but that I do. You'd have to stick it in a SEM to see it in detail. But basically you have two rough moon landscapes pushing down on each other. Usually the metal spring should be smoother than the PCB (Electroless nickel is quite porous), but the nickel in the PCB is quite a bit harder. So what you'd expect is that the surface roughness of the pcb is imparted on the contact wiper, however this is where contact force comes into play. Pushing down harder will decrease contact resistance by increasing mutual surface area (by deforming the spring preferably). As you move it around the interlocked sections have a chance of grinding away. So wider contacts with less force will indeed last longer, additionally wider pcb pads less likely to shear off.

What you'd also expect as a result is that high end meters would have better (smoother) plating on the contacts and use the soldermask to assist in holding down the pads on the PCB.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 20, 2017, 12:50:30 pm
It's the rotary switch wipers wearing out? I thought the PCB copper would wear out first, it's surely 1oz (1.4mil) or less.

Did you ever ask yourself why the bar on an electric train's overhead contact system doesn't wear out in a couple of days?

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=371951;image)

It's the same reason the rotary switch contact does. :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 20, 2017, 02:12:33 pm
Actually, since I am horribly bored in the cleanroom waiting for the vacuum press and laser to do their job, I'll disassemble a DT-830 and put the PCB under the profilometer  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 20, 2017, 07:38:43 pm
It's the rotary switch wipers wearing out? I thought the PCB copper would wear out first, it's surely 1oz (1.4mil) or less.

Did you ever ask yourself why the bar on an electric train's overhead contact system doesn't wear out in a couple of days?

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=371951;image)

It's the same reason the rotary switch contact does. :popcorn:

but the overhead cables have to be checked and regularly replaced!
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 21, 2017, 12:09:21 am
Did you ever ask yourself why the bar on an electric train's overhead contact system doesn't wear out in a couple of days?

That's actually complicated, and there have been evolving designs for contact materials and other factors to improve performance.

One key element is that the overhead wire sweeps from side to side and does not have a single contact patch on the pantograph.
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on November 21, 2017, 04:47:34 am
You, sir, have WAY too much cool gear, and I'm insanely jealous.  :-DD

Seriously though you've gotta show some of this off in a video.  How else can you justify it?   :-D



Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on November 21, 2017, 05:41:15 am
Did you ever ask yourself why the bar on an electric train's overhead contact system doesn't wear out in a couple of days?
It's the same reason the rotary switch contact does. :popcorn:

Electric train's pantograph uses carbon strips, (http://www.chemeng.lth.se/ket050/Finalreport2010/Carbonstrip.pdf) softer than copper- like in a brushed DC motor commutator. But I see your point about the physics.

Thickness of the PCB copper compared with the wiper metal, I thought around 1/10 and thinner would lose. The wear model says it's hardness and force.
Another factor I notice is switch diameter makes the far outside (ring) path longer so the inner rings (wipers) don't wear as much.

Just looking at it to see why the cheap meters rotary switches did poorly. They have to redesign their wiper, less force it seems.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 21, 2017, 06:36:16 am
Actually, since I am horribly bored in the cleanroom waiting for the vacuum press and laser to do their job, I'll disassemble a DT-830 and put the PCB under the profilometer  >:D

That would be an easy test.  Let's see what you came up with.

I'm wondering if the problem is in the wipers, not the PCB traces. When the wiper starts to look like this it makes sense (to me) that it will wear out the PCB/traces much faster.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=371798;image)

And as noted, the wear on the PCB/traces is spread out over the entire turn of the dial. It's a lot less than the concentrated 100% wear on the wiper.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 21, 2017, 06:39:45 am
Electric train's pantograph uses carbon strips, (http://www.chemeng.lth.se/ket050/Finalreport2010/Carbonstrip.pdf) softer than copper

"Pantograph". That's the word I couldn't remember...  :-DD


One key element is that the overhead wire sweeps from side to side and does not have a single contact patch on the pantograph.

Spoiler!

I wonder if they could to the same with rotary switch traces on PCBs. It would look pretty if they weaved from side to side.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 21, 2017, 07:50:29 am
Actually, since I am horribly bored in the cleanroom waiting for the vacuum press and laser to do their job, I'll disassemble a DT-830 and put the PCB under the profilometer  >:D

That would be an easy test.  Let's see what you came up with.

Forgot the DT830 at home, but we have a whoooole pile of Uni-T 61Es :D
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on November 21, 2017, 10:02:27 pm
The contact pressure (force/area) is probably the thing to look at.
You'd have to estimate the contact (wiper) area and its cantilever spring force. Maybe a phono cartridge tracking force gauge or the drug dealer special (scale) would explain the high wear.

Checked and my AN8008 has all copper wipers, no steel. Not sure if annealed or hardened.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 21, 2017, 10:56:44 pm
The contact pressure (force/area) is probably the thing to look at.

Right because the obviouse hole in the middle of the pad couldn't have anything to do with it.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 21, 2017, 10:59:40 pm
Someone was using it for proper work so couldn't exactly kick them of it to do my measurement. But I'll just do it on Thursday then, for now you can pick which DT-830 I should let suffer.  ;D

A few side notes: The black one on the left seems to kind of work as intended and has the best build quality. The yellow and crappy blue one have unfinished soldering on the transistor tester, and I had to open up the miniature ANENG to losen the tension on the PCB so I could operate the rotary switch.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 21, 2017, 11:31:31 pm
The left one is the "upgraded" temperature model. The best version I think (functionality, otherwise the small version looks great, such a small size). I don't have one and can't say about the inside.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 21, 2017, 11:49:41 pm
the yellow one should suffer, i hate that colour.
it always makes me think of telephone engineers!!
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on November 22, 2017, 01:34:02 am
Joe, I just noticed something..
As per the poll atop the thread (and doubled sub's), maybe we're gonna be need a holiday custom BBQ and Fireworks?

I for one would like to see if a lightly smoked Fluke 10 or 12 would ruffle those YouTube button pushers  :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 22, 2017, 02:42:43 am
Wife says no on this one.
:-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 22, 2017, 02:52:05 am
Wife says no on this one.

But delivered in 15-25 working days!
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on November 22, 2017, 03:23:10 am
Wife says no on this one.

But delivered in 15-25 working days!
Too fast, the models in my day took 9 months!

Why would they supply 10 amp leads if it only can do 600ma?
(https://s33.postimg.org/j6hriqgkv/Tacklife_DM06_600ma_max.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on November 22, 2017, 04:19:09 am
https://www.amazon.com/HJLHYL-MS8233B-Multifunction-Digital-Multimeter/dp/B01MTJMSLZ/ref=sr_1_238?ie=UTF8&qid=1511316372&sr=8-238&keywords=multimeter (https://www.amazon.com/HJLHYL-MS8233B-Multifunction-Digital-Multimeter/dp/B01MTJMSLZ/ref=sr_1_238?ie=UTF8&qid=1511316372&sr=8-238&keywords=multimeter)

Wife says no on this one.

Looks very robust though.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: CustomEngineerer on November 22, 2017, 05:51:01 am
https://www.amazon.com/HJLHYL-MS8233B-Multifunction-Digital-Multimeter/dp/B01MTJMSLZ/ref=sr_1_238?ie=UTF8&qid=1511316372&sr=8-238&keywords=multimeter (https://www.amazon.com/HJLHYL-MS8233B-Multifunction-Digital-Multimeter/dp/B01MTJMSLZ/ref=sr_1_238?ie=UTF8&qid=1511316372&sr=8-238&keywords=multimeter)

Wife says no on this one.

Nice back light though.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 22, 2017, 06:41:51 am
https://www.amazon.com/HJLHYL-MS8233B-Multifunction-Digital-Multimeter/dp/B01MTJMSLZ/ref=sr_1_238?ie=UTF8&qid=1511316372&sr=8-238&keywords=multimeter (https://www.amazon.com/HJLHYL-MS8233B-Multifunction-Digital-Multimeter/dp/B01MTJMSLZ/ref=sr_1_238?ie=UTF8&qid=1511316372&sr=8-238&keywords=multimeter)

Wife says no on this one.
Women never understand.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 22, 2017, 06:57:54 pm
Why would they supply 10 amp leads if it only can do 600ma?

Simple: Because they want the Ohms measurements to be super accurate.
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on November 22, 2017, 07:04:02 pm
Why would they supply 10 amp leads if it only can do 600ma?

Simple: Because they want the Ohms measurements to be super accurate.

How would printing 10A on the probe help with that? Even probes with fairly thin wires has the 10A stamp on them.

The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 22, 2017, 08:11:02 pm
The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.

Not if it was a "600mA" probe.  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on November 22, 2017, 08:48:57 pm
The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.

Not if it was a "600mA" probe.  :popcorn:
Things hide in plain sight  :palm: those probes looked familiar (same shorty's that came with my Aneng 8002).
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on November 22, 2017, 08:54:54 pm
Things hide in plain sight  :palm: those probes looked familiar (same shorty's that came with my Aneng 8002).

The Aneng probes are about 0.06ohm each.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on November 22, 2017, 10:34:42 pm
Things hide in plain sight  :palm: those probes looked familiar (same shorty's that came with my Aneng 8002).

they arent like the ones that came with mine.
(https://img.banggood.com/thumb/water/oaupload/banggood/images/66/5B/444150e7-0dc3-4e24-b5c9-89980c10f896.JPG)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 22, 2017, 10:49:13 pm
Why would they supply 10 amp leads if it only can do 600ma?

Simple: Because they want the Ohms measurements to be super accurate.

How would printing 10A on the probe help with that? Even probes with fairly thin wires has the 10A stamp on them.

The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.
This all seems to be true.

Here I am attempting to put 10A through various probes.  Note that the two 830s never made it up this high.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 22, 2017, 10:51:32 pm
This is looking at the power each probe is dissipating for this amount of current.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 22, 2017, 10:55:38 pm
And this is the calculated resistance.  Most even with 10A are below 0.1 ohms.
 
I had recently ran the probes that were provided with my Kasuntest ZT102 (AN8002).   The second plot is comparing this probe against my old and new style ProbeMaster probes as I sweep the current from 2A to 20A. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 22, 2017, 11:05:10 pm
I played around a little more with the home made lens adaptor trying to improve it.  It's alright but I would guess a cheap microscope would out perform it.

 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 22, 2017, 11:07:16 pm
Likely. However, the mac12 image is probably plenty of magnification and it's nice and clear.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 22, 2017, 11:52:43 pm
Depends how cheap the microscope is, the $16 USB one has 640 x 480 res, otherwise it's not too bad.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2017, 12:55:51 am
If you have one, post a few pictures off it along with what model number it is.   

To get a decent view of the wiper's contact area I would like something that would focus over a longer depth.  I glued the two worst wipers along with a good one to a chunk of plastic to save for later.  I noticed that the one contact was wore even worse.  A few more rotations and I think the center would have fallen out. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 23, 2017, 09:29:40 am
Can anybody test the hardness of the metal in the wipers? I'm sure that's a big factor.

A wiper that stays smooth, that doesn't develop sharp edges in use, could make a huge difference to longevity.
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 23, 2017, 11:47:06 am
If you have one, post a few pictures off it along with what model number it is.   

You didn't specify the subject of images exactly (probably just to see the microscope quality), so I opened a similar model to the "free meter" (DT830) and posted some random images. I didn't get to the wipers as it's easier not to have to put them back on (I managed to do it wrong once, it's good to always keep track where each goes). The LM image is not from the meter.

Random example images:
https://i.imgur.com/NpHJKyR.jpg
(Some are "doubled" as I usually hit the button a few times, then choose the clearer image)

Scope:
Don't know the model, but searching USB Microscope I found it from an image:
(https://i.imgur.com/6WwIfB4.png)


I used the overhead lighting it has built in which consists of 6 built in LED-s which you can control with a potentiometer on the cable (using some PWM I assume). It would be better to have very powerful ambient lighting and not use the LEDs if possible, to avoid glare. Focus is manually adjustable, but you also adjust zoom at the same time. So you usually need to adjust both height of the microscope and the zoom/focus adjustment to get a clear image at the desired magnification. The plastic stand can crack (near where the rod attaches to the base, which gets most force when you position the microscope up/down), but I've noticed that superglue (cheapest type, no more than $0.4-0.6) solves this, now it's pretty durable with no issues for a few years. The field of view is also not very large (unless you move it far away and use as a webcam), but at 640 480 it would not get great detail over a huge area anyway. I'm not sure I would recommend it to someone, especially if they are able to buy a more expensive unit, but considering the price it is better than I would expect.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 23, 2017, 12:34:20 pm
I'm not sure I would recommend it to someone, especially if they are able to buy a more expensive unit, but considering the price it is better than I would expect.

https://www.youtube.com/watch?v=H2P1_JZYnVc (https://www.youtube.com/watch?v=H2P1_JZYnVc)
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 23, 2017, 12:44:12 pm
Dave's came with a different, potentially less useful stand. Although, this one is not exactly quality, but after some fixing up it works. It does seem a bit more laggy in the video as well (for me it's relatively fluent when the overhead light is on, and of course quite slow when there is no light - but you can't see much anyway), but this will greatly depend on the light, software and hardware it is being tested on.

As for using it to actually do soldering, I haven't tried that as I don't think the working distance is great (plus the stand is plastic, needs some care or protection). It might be possible, but it doesn't seem right for that task.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2017, 04:51:28 pm
The $60 unit may be better than my home made setup.  Personally, I have never used a camera to solder with.  It would be nice to have something where the stage could be remote controlled.   

Looking at the free meter, the contacts really don't look too bad.  The majority of the damage is in the pads where the vias are.  The area of the pads where there is no vias looked fine.  But that meter had less than half the cycles on it than the other two.   

I was able to get both the Kasuntest and free meter working again with a little solder and swapping out the contacts from one of the other Kasuntests.  I will save these two meters for another test.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2017, 05:00:55 pm
I had ran this HP/Agilent/Keysight meter some time ago because of a video Dave had made where he showed the front end and made a comment to the effect of GDTs no worries.  The meter was not near as robust as I had hoped for.  I saved the meter in case I decided to do something with it.   I damaged the switch area with the half cycle generator but I looked at it today and it's just one set of pads on  outside ring.   The meter has no signs of grease.  I cleaned the area and removed the one outside contact to prevent it from digging away at the damaged area.  It may be worth cycle test it.  If it does poorly, we would not know for sure if a new would would be better.  At least they were smart enough not to put the vias in the pads.   

This meter uses two differnet spaced contacts.  The contacts are laid out similar to the UNI-T UT61.

Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 23, 2017, 05:25:33 pm
Is it possible/how would someone repair a contact like that first image S3B/S4B? I mean if someone found it worthwhile for whatever reason.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2017, 06:23:35 pm
Remove the solder mask.  Insert wire into the via. Fill with solder.  Maybe replace the contact.  Good enough for what they will be used for in the future. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2017, 09:57:16 pm
The Agilent has about 5000 cycles on it now.  I did remove the one contact before starting the test and cleaned the PCB and remaining contacts.   The cost for this meter is in the the same ballpark as the Fluke 17B+.   Feature wise, they each have their pros and cons.   The Fluke did much better in the transient tests.  Basically failing at 2X the voltage level of where the Agilent meter was damaged.  Let's see if Agilent can hang with the Fluke in this test.
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 24, 2017, 01:23:54 pm
Finally managed to sneak one of the DT-830 boards (yellow one) in between a time slot of a colleague.

Since I can't quite be bothered fighting filter settings on a Friday afternoon I'll go for the details. The surface roughness is surprisingly good (Ra of 600-700 nm), but just a few turns already caused noticable wear as you can see (2-3 micron trench).

Good area:
(https://i.imgur.com/gQ5Z1x0l.png) (https://i.imgur.com/gQ5Z1x0.png) (https://i.imgur.com/FqfnQuLl.png) (https://i.imgur.com/FqfnQuL.png)

Area where the contacts pass:
(https://i.imgur.com/7X9T57Pl.png) (https://i.imgur.com/7X9T57P.png) (https://i.imgur.com/JUPm1ETl.png) (https://i.imgur.com/JUPm1ET.png)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 24, 2017, 06:16:43 pm
Can you scan a larger area to show more than one pad so we can see the thickness of the pads along with the surface finish?

HPAK:  The new face of HP-Agilent-Keysight

The HPAK meter has been cycling for well over 24 hours now.  I plan to make a separate very short video just for this meter to show the changes to the software.  I wanted to try and make the data a little easier to understand.  So I have changed the histograms to display in a bar graph.  The width of the bar represents the size of the bins.   For the log/log I changed the minimum resistance from 5mohms to 1mohms and then added a limit line.   Basically there is now a line drawn for the maximum cycles for the data set being viewed along with it starting and ending on the min/max resistance range.   I did not come up with a reason to view the data as a percentage as the one person requested.  They would need to elaborate on what they were thinking then maybe we could add a new graph if it proved helpful. 
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 24, 2017, 07:19:43 pm
Yeah, just takes a lot of time to do that scan. It can do about 1x1 mm at once, but for a scan depth of 80 µm as I was using it easily takes 20 - 30 seconds/sq. mm The heavy user of the machine is off to a conference so should be able to use it next week without feeling guilty.  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on November 24, 2017, 08:09:26 pm
Looks like a great tool. What technology/sensor type does it use to detect height/depth of a point?
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 24, 2017, 08:18:11 pm
Looks like a great tool. What technology/sensor type does it use to detect height/depth of a point?

It's based on visible light interferometry. You can find quite a bit on it if you google "Veeco Wyko".  ^-^  But Veeco seems to have sold it off to Bruker: https://www.bruker.com/products/surface-and-dimensional-analysis/3d-optical-microscopes.html (https://www.bruker.com/products/surface-and-dimensional-analysis/3d-optical-microscopes.html) You'll find one of these Wyko optical profiler systems in almost any electronics cleanroom, they have extremely good resolution in all three axis, are reasonably priced, and very easy to operate. The only flaw these things have is that the tilt/tip system of the sample stage can get stuck.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 25, 2017, 02:47:23 pm
I figured it would take a while but you may be able to change some of the settings to scan a wider area with less accuracy just to get us in the ballpark. 

48 hours on the H-PAK meter now.  I wonder why Bill got the short stick in the rename.  We can tell they were trying to spell Dave's last name.  Seems like the next two company names should start with "E" and then "W" to make thing fair.   

Anyway, it's in the home stretch now.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 25, 2017, 08:59:22 pm
Warning, it's not a good video for the H-PAK fan boys to watch.   For the rest of you wanting to see it, here's the U1231A.

https://youtu.be/z9732OYPRx8
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 25, 2017, 11:45:04 pm
Joe, that does not look good at all, especially the mechanical wear of the position stops. It makes me wonder if operating the switch with the thumb would wear it even more due to the off-centered pressure applied.

I suspect the more expensive HPAK meters also use the same position stop mechanism.

Regardless, I imagine folks may be up in arms either (1) complaining about you testing a damaged meter or (2) crying foul trying to devaluate HPAK meters solely based on your overkill usage scenario.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 01:05:07 am
When I was looking for a good handheld meter to use on the bench, I had looked at Keysight.   I wrote them a few times but no one responded.  Had they, I would ask them about the spring failure.  It really took me by surprise.   

It has not came up yet but if you watch the very first part of the video, the switch had a nice clean and sharp click to it.   This was right after I had setup the test.  The meter had ran a few thousand cycles by the time I decided to make the intro.  By then the damage had been done or at least the click was not near as pronounced.   I was glad I had captured some video what it first sounded like just to give people some contrast. 

You could be right about the thumb wheel causing the parts to wear even faster.  I suspect the spring would fair at the same rate.  I wonder if they had a bad batch of plastic parts and their quality department didn't catch it or someone wrote a deviation to allow them to be used.  Hard to say.  I doubt we would ever know shy of running more of them and seeing if they fail the same.

I get complaints all the time for one reason or another.   This would not be the first time I have been called out for demoting or devaluing a brand.  The problem with this mind set is that it somehow suggests I have something to do with the end product which I certainly have no part in.  I just test them on a level playing field and report my results.   To your other point about it being an overkill usage scenario, that could very well be.   I have yet to find any documentation where the manufacture calls out the number of life cycles the switch is rated for.   Of course, if I am designing a product that uses a switch, the life cycle is something I am looking at.  I find it hard to believe they don't know.  Perhaps their marketing departments do not feel the life of the product is a selling point.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 02:22:21 am
In the attached plot showing the resistance, it looks like it really started to get bad about 6500 cycles into the test.   I thought about aborting the test but the switch started to make contact again and I wanted to see the visual damage with the same number of cycles as the Fluke.    Note the Fluke is the RED plot at the very bottom.  Now that is what a switch should act like.     

I think more than one person would want to see a UNI-T ran on this test.   I currently have two 210s, 90, 181 and a 61E.  None of these are a very good fit to run.  The 210s would be difficult to attach to without some modification to the knob.  The 90 has been repaired more times than I care to count which includes heavy damage to the switch.  Both the 61 and 181 have had circuit board modifications to them.   

I believe the two AMPROBE branded meters I have were made by UNI-T.  Both meters are still in excellent condition as they only are used for comparisons.  Both use a screw and fiber washer that holds the switch assembly to the PCB.  So it's not like the UT61E and other UNI-T meters I have looked at.    It does appear they did not place the the vias in the pads.  After seeing how quickly the H-PAK meter failed, it's not a guarantee the switch will survive.   

Another option is to buy one more UNI-T branded meter and run it.  May be time for a new poll.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 02:41:49 am
Looking at the the first 7000 cycles from 0.35 to 0.5 ohms for all four meters.  The free meter is off the charts within 500 cycles.  But it's free.   More interesting is I would expect there to be a major difference between the H-PAK and the Kasuntest but show signs of problems right from the start.   The Fluke on the other hand actually improves.  I suspect the parts are seating together.  I know you people like to compare meters with cars so something like breaking in a new car engine.  Once the contacts seat, the are even more consistent.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 26, 2017, 03:28:07 am
The switch spring failure in the Keysight is unfortunate. Hopefully, their higher-end meters have a better/more durable mechanism. Too much plastic everywhere!
Title: Re: Handheld meter electrical robustness testing.
Post by: Paul Moir on November 26, 2017, 06:14:57 am
It's not too much plastic, it's the wrong plastic.  Notice that fluke makes the spring out of a different plastic than the housing.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 26, 2017, 10:52:04 am
The switch spring failure in the Keysight is unfortunate. Hopefully, their higher-end meters have a better/more durable mechanism.

"Unfortunate" isn't the word I'd use - it's probably not bad luck.

It'd be worth running another one in batches of 500 cycles just to figure out exactly when the switch breaks. For all we know it might have broken after 1000 cycles (there's obviously nothing left after a "few thousand"). 1000 cycles would only be a dozen measurements per day for 3-4 months.

As for "Hope"? I'd want proof.  :popcorn:

PS: I wonder if user 'Keysight DanielBogdanoff' reads this thread. Keysight's reputation for multimeters needs some salvage work here. Maybe he could send Joe some meters to test. :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: nctnico on November 26, 2017, 11:14:18 am
Regardless, I imagine folks may be up in arms either (1) complaining about you testing a damaged meter or (2) crying foul trying to devaluate HPAK meters solely based on your overkill usage scenario.
IMHO it is good to test stuff until it breaks.The problem is ofcourse that this is just one sample which may be very good or very bad. There is no way to tell other than testing 20 units.
From the graph it seems this one broke after about 6000 cycles. You would have gotten over 4 years of life out of it if you turned the switch 5 times a day on every work day.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 26, 2017, 11:19:02 am
From the graph it seems this one broke after about 6000 cycles.
The range selector's wipers aren't related to the switch's clicker mechanics, IMHO, so the graph can't show anything about the clicker.

The switch is definitely not clicking at all in the intro video (after "a few thousand" cycles).

Joe: You took a photo of the meter at 5000 cycles (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1357096/#msg1357096). Was that before or after recording the intro video? By how much time, approx? That event might give a ballpark clue as to where it failed.
Title: Re: Handheld meter electrical robustness testing.
Post by: HighVoltage on November 26, 2017, 11:21:29 am
I would be surprised if the Keysight higher up meters like the U1273A or the U1253B would behave the same way. I have both and so far they seem reliable.

Yes, may be Keysight will send you some DMMs for testing.
 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 26, 2017, 11:23:12 am
I would be surprised if the Keysight higher up meters like the U1273A or the U1253B would behave the same way. I have both and so far they seem reliable.

Could you pop one open and see if the switch clicker is made of decent plastic, like the Fluke?

Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on November 26, 2017, 11:41:45 am
Broken plastic spring is not a problem. Keysight could send you new one made of better plastic. It is the contact damage, board damage and resulting contact resistance that is problem. Board traces are definitely damaged too soon, and that you can't fix easily. It is obvious that PCB integrated switch is not so robust solution in general, and that tested Fluke seem to does it quite nicely and better than the rest of the tested ones..
This is one of those moments when Fluke actually lives up to it's reputation. I'm really curious now as to how Brymen would stand up to this test..
Like Joe, my BM869S is also my favorite meter. I prefer it to others, and actually bought it instead of Fluke 87/V because it was better for my use, not cheaper.
I wonder if maybe switch related problems might be is it's Achilles heel.. Or maybe it stands up to Fluke on that test too?
Would be really interesting to know.

Also, as far as Uni-T goes, I guess 61E would be the one.. Despite not being very electrically robust, it is a good little, inexpensive meter for electronics desk and many people have one and it would be nice to know how long it's gonna last...

Other choice would be 181, that is fully featured meter good for low power electronics work, but it is not that cheap. Would be nice to know how long it's switch would last..

Regards,

Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 26, 2017, 11:52:20 am
Broken plastic spring is not a problem. Keysight could send you new one made of better plastic.

Sure, if you have a local office, a business account with them and the extension number of a support rep.

Good luck if you're in another country or just an individual, eg. Joe couldn't get a reply (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1357096/#msg1357096) out of them.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on November 26, 2017, 12:25:51 pm
Broken plastic spring is not a problem. Keysight could send you new one made of better plastic.

Sure, if you have a local office, a business account with them and the extension number of a support rep.

Good luck if you're in another country or just an individual, eg. Joe couldn't get a reply (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1357096/#msg1357096) out of them.
You are correct in that regard, I didn't think of that that way.

But to be sarcastic, isn't that the reason to pay big bucks to renowned companies, because they don't just sell you products, they give great support...

So far Joe had no particularly good support from Gossen Metrawatt, Keysight... Actually Brymen is known to answer questions... 

My own experience is that big names have great support only if you are a big customer.
I'm bussines customer, but a small one and nobody cares for my few hundred bucks, even few thousand every now and then.. 
6.5 digit benchtop meters are now retail channel products, if you don't need at least 5-10 at a time..

Hence, Brymen for me... Works great, an even it if it doesn't last 10-15 years, at least I payed 30% of the price.. In 15 years, I can buy new one every 5 years, toss old one in the garbage, and still break even compared to "big names", while having excellent instrument that was in warranty period most of the time..
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 26, 2017, 12:57:15 pm
Broken plastic spring is not a problem. Keysight could send you new one made of better plastic.
Sure, if you have a local office, a business account with them and the extension number of a support rep.
You are correct in that regard, I didn't think of that that way.

But to be sarcastic, isn't that the reason to pay big bucks to renowned companies, because they don't just sell you products, they give great support...

I'd rather they made good products that don't need any more support than a worldwide speedy-replacement warranty for DOA devices.

Right now the Fluke 17B+ is looking a lot less overpriced than it did a couple of weeks ago. 

PS: Maybe Joe could send the meter to 2N3055 and 2N3055 could document the process of getting them to fix/replace it. It's easy, right? :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on November 26, 2017, 01:13:10 pm
Broken plastic spring is not a problem. Keysight could send you new one made of better plastic.
Sure, if you have a local office, a business account with them and the extension number of a support rep.
You are correct in that regard, I didn't think of that that way.

But to be sarcastic, isn't that the reason to pay big bucks to renowned companies, because they don't just sell you products, they give great support...

I'd rather they made good products that don't need any more support than a worldwide speedy-replacement warranty for DOA devices.

Right now the Fluke 17B+ is looking a lot less overpriced than it did a couple of weeks ago. 

PS: Maybe Joe could send the meter to 2N3055 and 2N3055 could document the process of getting them to fix/replace it. It's easy, right? :popcorn:

As a pure hobbyist, don't even try. On the other hand if you work for a company or university and often deal with them, then you can get lucky sometimes.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 01:44:58 pm
Regardless, I imagine folks may be up in arms either (1) complaining about you testing a damaged meter or (2) crying foul trying to devaluate HPAK meters solely based on your overkill usage scenario.
IMHO it is good to test stuff until it breaks.The problem is ofcourse that this is just one sample which may be very good or very bad. There is no way to tell other than testing 20 units.
From the graph it seems this one broke after about 6000 cycles. You would have gotten over 4 years of life out of it if you turned the switch 5 times a day on every work day.
This sort of comment does come up from time to time.     Somewhere in this long pile of posts there is a section on it,  or you could check the FAQ as I believe I cut and pasted it there as well.     I would hope that H-PAK' quality control group has a hand process that is under control but you never know.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 01:59:31 pm
From the graph it seems this one broke after about 6000 cycles.
The range selector's wipers aren't related to the switch's clicker mechanics, IMHO, so the graph can't show anything about the clicker.

The switch is definitely not clicking at all in the intro video (after "a few thousand" cycles).

Joe: You took a photo of the meter at 5000 cycles (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1357096/#msg1357096). Was that before or after recording the intro video? By how much time, approx? That event might give a ballpark clue as to where it failed.

The first thing I did was pull apart the meter to inspect it.  I took pictures of the switch as well.  Once it was setup, I took a picture of the setup and then shot some video of it.   In the picture you reference, the Cannon is mounted on the tripod to the far right.  Normally for stills, I like using that Sony.   

I never would have guessed the meter would have problems this early on and I was not thinking too much about what the video was even going to show other than the changes I had made to the graphing.   By the time I checked in on the test, it was too late.  This is when I shot the intro.   The meter started that bit of a squeak so I captured that but it slowly went away as the meter continued to cycle.

The cycle time varies.  Windows is not a real predictable OS.   I would guess somewhere in the 2-3 hour range when I noticed it with a fairly low confidence.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 02:15:22 pm
Broken plastic spring is not a problem. Keysight could send you new one made of better plastic. It is the contact damage, board damage and resulting contact resistance that is problem. Board traces are definitely damaged too soon, and that you can't fix easily. It is obvious that PCB integrated switch is not so robust solution in general, and that tested Fluke seem to does it quite nicely and better than the rest of the tested ones..
This is one of those moments when Fluke actually lives up to it's reputation. I'm really curious now as to how Brymen would stand up to this test..
Like Joe, my BM869S is also my favorite meter. I prefer it to others, and actually bought it instead of Fluke 87/V because it was better for my use, not cheaper.
I wonder if maybe switch related problems might be is it's Achilles heel.. Or maybe it stands up to Fluke on that test too?
Would be really interesting to know.

Also, as far as Uni-T goes, I guess 61E would be the one.. Despite not being very electrically robust, it is a good little, inexpensive meter for electronics desk and many people have one and it would be nice to know how long it's gonna last...

Other choice would be 181, that is fully featured meter good for low power electronics work, but it is not that cheap. Would be nice to know how long it's switch would last..

Regards,

Sinisa

I am not sure what problems the spring could actually cause.  I run a test where I put a full rectified 220V 60Hz wave into the meters and cycle them through all the functions.  The generator detects an over current condition (I think I have it set to 40mA or so) and will shut down to limit any damage.  There were several comments about how I was cycling the meters with power applied.  Without the spring, the switch will not lock to its centered location.  It could even move fairly easily. Could this cause something to happen?  I have no idea.  Certainly, I could see someone reading a 440 bus having the meter  slip off the contacts and start reporting something other than the 440.   Could this create a hazardous condition?     Keep in mind, this meter has no current input.  It uses an external clamp.   It's not something you would want as an electronics hobbyist.   

What bothers me with some of these meters is all that metallic residue around the switch contacts.  I doubt IEC even considers that the meter should be life cycled before running surge.  That residue could play into it.   For us low energy hobbyist, well for me anyway,  the life is more important.   

Your comment about BM869s is true for me as well.  The cost really didn't play into it nearly as much as what the product offered.  I plan to run at least one Brymen product.  It should make for a good video.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on November 26, 2017, 02:37:32 pm
I am not sure what problems the spring could actually cause.  I run a test where I put a full rectified 220V 60Hz wave into the meters and cycle them through all the functions.  The generator detects an over current condition (I think I have it set to 40mA or so) and will shut down to limit any damage.  There were several comments about how I was cycling the meters with power applied.  Without the spring, the switch will not lock to its centered location.  It could even move fairly easily. Could this cause something to happen?  I have no idea.  Certainly, I could see someone reading a 440 bus having the meter  slip off the contacts and start reporting something other than the 440.   Could this create a hazardous condition?     Keep in mind, this meter has no current input.  It uses an external clamp.   It's not something you would want as an electronics hobbyist.   
I wouldn't presume to speculate what electrical damage might happen to the switch and meter because of switch locking between ranges. I was merely pointing out that mechanically, PCB wear was terminal damage to the meter and not the broken spring. If the PCB was not damaged meter would be repairable by just replacing knob. Also I don't think springs being damaged contributed to PCB and contacts excessive wear, and that those two failures should be considered separately, despite being same switch assembly.

What bothers me with some of these meters is all that metallic residue around the switch contacts.  I doubt IEC even considers that the meter should be life cycled before running surge.  That residue could play into it.   For us low energy hobbyist, well for me anyway,  the life is more important.   
I think that is excellent point, especially if there is lubrication on the switch that will retain metallic filings and particles, essentially making it into conductive paste over time...

Your comment about BM869s is true for me as well.  The cost really didn't play into it nearly as much as what the product offered.  I plan to run at least one Brymen product.  It should make for a good video.
Agree. Looking forward to it!

Take care!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 02:49:37 pm
I'd rather they made good products that don't need any more support than a worldwide speedy-replacement warranty for DOA devices.

Right now the Fluke 17B+ is looking a lot less overpriced than it did a couple of weeks ago. 

PS: Maybe Joe could send the meter to 2N3055 and 2N3055 could document the process of getting them to fix/replace it. It's easy, right? :popcorn:

I have never considered returning a meter that I ran in for repairs as I knowingly run them to failure.   IMO, this is the whole point of doing a review.  If you are just hooking to a few resistors and some batteries, what's the point.    When I was talking with Brymen about transient testing the BM869s, I told them I was going to test it to failure.  Tell this to any other meter company and let me know how they respond.   Brymen's response:

Quote
In case BM869s is damaged out of your transient tests, we will be willing to specially offer free warranty repair or replacement to you.

And when I did finally damage it I offered to return it for a failure analysis.  I also provided them with a little background and offered to do the FA myself.   Their response was:

Quote
If you can not repair it, please send it back to us. We will either repair it or replace it by a new one back to you.

Of course, I was able to repair the meter and have been using it ever since.  Point being that their communications have proven time and time again to be second to none.  At least from my perspective.  When a user had posted about the strange settling times,  I wrote them and we pretty much had an immediate response, including the source for that section of code.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 03:00:12 pm
I am not sure what problems the spring could actually cause.  I run a test where I put a full rectified 220V 60Hz wave into the meters and cycle them through all the functions.  The generator detects an over current condition (I think I have it set to 40mA or so) and will shut down to limit any damage.  There were several comments about how I was cycling the meters with power applied.  Without the spring, the switch will not lock to its centered location.  It could even move fairly easily. Could this cause something to happen?  I have no idea.  Certainly, I could see someone reading a 440 bus having the meter  slip off the contacts and start reporting something other than the 440.   Could this create a hazardous condition?     Keep in mind, this meter has no current input.  It uses an external clamp.   It's not something you would want as an electronics hobbyist.   
I wouldn't presume to speculate what electrical damage might happen to the switch and meter because of switch locking between ranges. I was merely pointing out that mechanically, PCB wear was terminal damage to the meter and not the broken spring. If the PCB was not damaged meter would be repairable by just replacing knob. Also I don't think springs being damaged contributed to PCB and contacts excessive wear, and that those two failures should be considered separately, despite being same switch assembly.
I am not a plastics expert but the spring does appear to be made of a glass filled plastic.  If the spring would have created some sort of dust, I guess it could contribute to the contacts wear.  All the breaks appear clean and I saw only minimal plastic dust and none of it appeared on the circuit board from what I could tell.  So I tend to agree. 

I don't have a metric for spring failures.  Actually, the only thing I can do is show the before and after for the mechanical parts and leave it to the viewer to decide if its a problem or not.  We certainly saw a fair amount of damage to the detent area on free meter as well as the Kasuntest.   I thought about measuring the torque in real time as another metric but decided it was more trouble than it was worth. 
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on November 26, 2017, 03:16:35 pm
Great job as always, Joe.  There are very few public tests to show meters live up to their spec as you have.  Switch failure, plus the way you present the data make it fairly clear Fluke does put more into its DMMs, even offshore meters.  I look forward to your Brymen tests in the future.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on November 26, 2017, 04:31:09 pm
I look forward to your Brymen tests in the future.

Is the BM869 about to take one for the team?  :o
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on November 26, 2017, 04:53:47 pm
Spring is made I guess with a glass filled nylon, probably 30% glass by volume, as that is a pretty common material, and is quite robust and resilient. however for a decent spring that arm should have been thinner, plus the nylon should have been non filled, which would mean they would have had to use 2 moulds to make the outer knob and shaft in a 30% glass filled nylon for robustness, and then the inner spring section as a slip on collar that would have the flex required to survive long term operation as a spring material. In that case I would guess the lifetime would be well past the 50k cycle life, and the wear on the end sections of the spring in the detents would also be a lot less.

Would prefer though that the manufacturers used a thicker gold plate on the switches, along with a thicker gold plate ( or a welded on German silver contact pad) on the wipers, so that the operational lifetime would be longer. However that would require a selective plate on the board, or for them to use a small daughter board that has the contact pads on there, with a set of mousebites or pins to allow the 2 boards to be connected. Might be doable, thin PCB material with double sided etch, lots of small vias and a heavy gold plate, plus plated milled vias on the edges for soldering to the main board, and some solder pins to both locate and carry current. Main board would just need a thin precut insulator to prevent arcing over between traces, and would be cheaper than a bespoke switch, plus frees up board space to route traces on the front and components on the rear of the switch as well. 
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on November 26, 2017, 05:10:02 pm
My old Fluke 73/III had a real switch, and a separate spring assembly, that spring assembly had separate part number...
I guess they really don't make them as they used to...  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 05:18:17 pm
I look forward to your Brymen tests in the future.

Is the BM869 about to take one for the team?  :o
I don't want there to be any question in peoples minds about the state of the meter prior to running the test and my BM869s has seen a lot of use since I purchased it.  The right thing would be to run a brand new one right out of the box.

I would be fine running the EEVBLOG rebranded Brymen as it has only been used for reviews and should be in near mint condition.  However, this meter has never been damaged and at some point, I may put together some sort of shoot out for the meters that have survived these tests out of the box.   The Fluke 107 will be a tough meter to beat.   

At some point I would like to repeat the tests I ran on the 121GW now that it has been released.   I am a little concerned about the comments Dave made in the last Amphour show about wanting to change the board again.   Because of the time invested in making these videos, I want to make sure that I don't run into a case only to have them say there is a new hardware change in the works.   My plan would be to release the videos I had made of the preproduction prototype proof of concept, or what ever we are calling it now and show how the released meter addressed the problems I had found.   My plan would be to include the life cycle testing as part of the review.    I think as long as I stay away from that half cycle generator until the very end, the switches should be fine to life cycle after the normal testing.   It may be a while for them to go through the 2000 boards they have in stock so don't look for this to happen any time soon. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 06:16:53 pm
There maybe some confusion what the H-PAK's switch assembly looks like once it's apart.   



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 06:36:43 pm
My old Fluke 73/III had a real switch, and a separate spring assembly, that spring assembly had separate part number...
I guess they really don't make them as they used to...  :-DD

I have not seen any imaginary switches used in any of the meters I have looked at.  Or at least they appear real to the touch to me anyway.    :-DD  Sorry...  Anyway it looks like someone had posted some decent pictures of what yours looks like.   It appears to be a fiber wafer switch similar to what was in the TV sets from my youth.   It's too bad we can't get that time machine working or I would put together enough old cash, go back in time and buy some of these brand new and run them.  You would think the life would be much longer with the two contact but I have seen a lot of these go intermittent as well.     That Tachikawa I recently restored has a separate wafer switch as well.  This is not a high end meter by any means. 

https://www.eevblog.com/forum/testgear/t21362/ (https://www.eevblog.com/forum/testgear/t21362/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 06:39:51 pm
While the H-PAK meter is apart, I tried to take some better pictures of the damaged areas of the spring. 
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on November 26, 2017, 07:03:21 pm
My old Fluke 73/III had a real switch, and a separate spring assembly, that spring assembly had separate part number...
I guess they really don't make them as they used to...  :-DD

I have not seen any imaginary switches used in any of the meters I have looked at.  Or at least they appear real to the touch to me anyway.    :-DD  Sorry...  Anyway it looks like someone had posted some decent pictures of what yours looks like.   It appears to be a fiber wafer switch similar to what was in the TV sets from my youth.   It's too bad we can't get that time machine working or I would put together enough old cash, go back in time and buy some of these brand new and run them.  You would think the life would be much longer with the two contact but I have seen a lot of these go intermittent as well.     That Tachikawa I recently restored has a separate wafer switch as well.  This is not a high end meter by any means. 

https://www.eevblog.com/forum/testgear/t21362/ (https://www.eevblog.com/forum/testgear/t21362/)

Take a look here.. https://youtu.be/9ptPe_AeZiQ?t=509 (https://youtu.be/9ptPe_AeZiQ?t=509)

By all means, switches can be made right on a PCB. It's just that its not that easy as just thinly gold plating some pads and slapping some brass to slide on it...
Switch on 73 looks low tech, but seems robust enough.. And it is, that damn thing still works no problem.

Regards,

Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 26, 2017, 07:40:14 pm
One of the guidelines in studies of friction in bearings and sliding contacts is that the two mating surfaces should be made of dissimilar materials. In the case of the multimeter switch spring, I would think the plastic springy bit should be made of something hard and durable (maybe like nylon), and the outer ring with the detent slots should be made of something soft and slippery (like polypropylene?).

In the different cases of the meter switch that was durable (Fluke) and the one that wasn't (Keysight) it would be interesting to do a materials analysis of the different components to find similarities and differences. YouTube blogger Ave has often given hints on how to identify different plastics. One simple technique is to find the melting point with a soldering iron set to different temperatures. Sometimes there is even a meterial code embossed on the part.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 08:41:17 pm
One of the guidelines in studies of friction in bearings and sliding contacts is that the two mating surfaces should be made of dissimilar materials. In the case of the multimeter switch spring, I would think the plastic springy bit should be made of something hard and durable (maybe like nylon), and the outer ring with the detent slots should be made of something soft and slippery (like polypropylene?).

In the different cases of the meter switch that was durable (Fluke) and the one that wasn't (Keysight) it would be interesting to do a materials analysis of the different components to find similarities and differences. YouTube blogger Ave has often given hints on how to identify different plastics. One simple technique is to find the melting point with a soldering iron set to different temperatures. Sometimes there is even a meterial code embossed on the part.

The bearing surfaces show little signs of wear on the H-PAK.  However, once the plastic cracked we lost all the tension which would greatly reduce the wear. 

My plastics knowledge is VERY little.  I may be able to tell you if they are a thermoset or not by seeing if they melt at all.   
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 26, 2017, 08:54:43 pm
The bearing surfaces show little signs of wear on the H-PAK.  However, once the plastic cracked we lost all the tension which would greatly reduce the wear.

Yes, I saw the pictures of the crack after I posted. That basically looks like a catastrophic failure. The fact that it failed like that suggests that the mechanical engineers were either absent or failed to do a good enough job on the design.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 09:06:19 pm
A recent post from a viewer.  To be clear, my goal in posting this here in the forums is to open a discussion about running a test like this.  Do you feel all the meters would have to be brand new to gain any understanding about the switched life?   Do you feel we need to have different tests for different meters?   If so, what do you feel should be the criteria?    Do you feel there is no value in running the test because we are only looking at one meter?

Again, to be clear, I am leaning towards running the functional tests, followed by the transient tests just like I always have since I started doing more of a review.    After this, I would then life cycle them.  If there is anything left, I would then run the half cycle if I thought the meter would give us some sort of light show...  :-DD   It's obviously a sort of crap shoot with my videos as there are times when I make some pretty big changes to these meters just to try and get a better understanding about their designs.     

Feel free to chime in.  As far as I am concerned at this stage, there really are no wrong answers. 


Quote
 
Joe, very informative test as always! However, I think the fact that one of the pads
on the rotary switch was damaged initially fom prior tests you ran, should have negated
this particular meter  from your selector switch stress test no matter what you did to
repair/negate the problem. In a real word stress/performance scenario you just can't
bench-test a product and achieve a fair /accurate result if that product was altered
in any way, no matter how good the intentions.

(me)
I was very clear about the damage that had been done to the meter prior to the testing
along with what I had done to  mitigate it.   If you feel running a brand new unit with
near SNs would change the results,  I am perfectly fine with that.  I have no data that
shows one way or the other.    You are welcome to repeat the test and show your own
results
       
Indeed Joe. 3rd party Refurbished isnt a factory standard and as such I would take
any testing results with a grain of salt no matter how pretty the graphs might appear.
It's one thing to take a bevy of refurbished meters that had similar issues and produce
a final test result but it's quite another to compare dissimilar meters and try to accrue
some sort "precision" results based on the aftermath of varied component failures.
       
(me)       
I have disclosed if the meters were new, used or had damage to the switch area.  I assume
you are considering the repaired meters, like the Fluke a refurbished meter as it was
damaged during the transient tests and repaired by myself (3rd party) .   That's fine. 
It's only one meter, not really a bevy.    If you feel the Fluke would have performed
better (or worse) had Fluke performed the repairs, I am fine with that.  It could also
be that a brand new Fluke 17B+ would also perform better than the one I looked at.   
Again, I don't have any data one way or the other to suggest different.   If you feel
the same model Keysight meter from the same lot would yield different results, you are
certainly free to show your own data.  I would welcome it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2017, 09:13:55 pm
The bearing surfaces show little signs of wear on the H-PAK.  However, once the plastic cracked we lost all the tension which would greatly reduce the wear.

Yes, I saw the pictures of the crack after I posted. That basically looks like a catastrophic failure. The fact that it failed like that suggests that the mechanical engineers were either absent or failed to do a good enough job on the design.
I agree with your last comment.  Running an FEA on the parts my show something.  Then again, it may be more effort than it's worth.   

My iron will go down to 400F on the display.  Both the case and the spring will melt at whatever temperature this is at the tip.   The case has a much more even flow to it.  The spring appears to burn somewhat.  I agree with SeanB and suspect a filler.  The case appears to be a lot more flexible than the spring.     
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on November 26, 2017, 10:29:38 pm
For plastics, its straightforward for pure polymers, however, it will give confusing results for composites.

http://www.boedeker.com/burntest.htm (http://www.boedeker.com/burntest.htm)

http://www.chymist.com/Polymer%20Identification.pdf (http://www.chymist.com/Polymer%20Identification.pdf)

Except in the case of fiberglass, where after melting the remnants will be hard and dense other composites: wood, carbon fiber, etc., will burn with the plastic polymer, alter the color profile but will give mixed results for density tests.  Burn tests are toxic and potentially carcinogenic.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 27, 2017, 02:38:22 am
A recent post from a viewer.  To be clear, my goal in posting this here in the forums is to open a discussion about running a test like this.  Do you feel all the meters would have to be brand new to gain any understanding about the switched life?   Do you feel we need to have different tests for different meters?   If so, what do you feel should be the criteria?    Do you feel there is no value in running the test because we are only looking at one meter?

Again, to be clear, I am leaning towards running the functional tests, followed by the transient tests just like I always have since I started doing more of a review.    After this, I would then life cycle them.  If there is anything left, I would then run the half cycle if I thought the meter would give us some sort of light show...  :-DD   It's obviously a sort of crap shoot with my videos as there are times when I make some pretty big changes to these meters just to try and get a better understanding about their designs.     

Feel free to chime in.  As far as I am concerned at this stage, there really are no wrong answers. 


Quote
 
Joe, very informative test as always! However, I think the fact that one of the pads
on the rotary switch was damaged initially fom prior tests you ran, should have negated
this particular meter  from your selector switch stress test no matter what you did to
repair/negate the problem. In a real word stress/performance scenario you just can't
bench-test a product and achieve a fair /accurate result if that product was altered
in any way, no matter how good the intentions.

(me)
I was very clear about the damage that had been done to the meter prior to the testing
along with what I had done to  mitigate it.   If you feel running a brand new unit with
near SNs would change the results,  I am perfectly fine with that.  I have no data that
shows one way or the other.    You are welcome to repeat the test and show your own
results
       
Indeed Joe. 3rd party Refurbished isnt a factory standard and as such I would take
any testing results with a grain of salt no matter how pretty the graphs might appear.
It's one thing to take a bevy of refurbished meters that had similar issues and produce
a final test result but it's quite another to compare dissimilar meters and try to accrue
some sort "precision" results based on the aftermath of varied component failures.
       
(me)       
I have disclosed if the meters were new, used or had damage to the switch area.  I assume
you are considering the repaired meters, like the Fluke a refurbished meter as it was
damaged during the transient tests and repaired by myself (3rd party) .   That's fine. 
It's only one meter, not really a bevy.    If you feel the Fluke would have performed
better (or worse) had Fluke performed the repairs, I am fine with that.  It could also
be that a brand new Fluke 17B+ would also perform better than the one I looked at.   
Again, I don't have any data one way or the other to suggest different.   If you feel
the same model Keysight meter from the same lot would yield different results, you are
certainly free to show your own data.  I would welcome it.

The OP puts out their own handheld meter reviews.   I knew this but had never watched one until tonight.   My wife and I watched the one for a Sanwa meter that they had asked me to look at.  I was hoping to get some context on where they were coming from with their comments.  It's a little more clear now.   If you would like me to test meters more like this, feel free to let me know. 

https://youtu.be/CDsgVkHgE4g
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 27, 2017, 02:41:50 am
The switch spring failure in the Keysight is unfortunate. Hopefully, their higher-end meters have a better/more durable mechanism.

"Unfortunate" isn't the word I'd use - it's probably not bad luck.

"Unfortunate" also means regrettable.

Quote
As for "Hope"? I'd want proof.  :popcorn:

Certainly. Failures due to poor materials have resulted in the publishing of service notes and usually free repair/replacement of the bad parts. Alas, there isn't one about the function switch.

https://servicenotes.literature.keysight.com/litapp/SearchSN.do?method=openExternalSNSearch&prodNum=U1232A (https://servicenotes.literature.keysight.com/litapp/SearchSN.do?method=openExternalSNSearch&prodNum=U1232A)

Quote
PS: I wonder if user 'Keysight DanielBogdanoff' reads this thread. Keysight's reputation for multimeters needs some salvage work here. Maybe he could send Joe some meters to test. :popcorn:

He usually pops in on scope threads, but sometimes on other ones that mention HPAK equipment. I haven't seen him in this one, yet.
Title: Re: Handheld meter electrical robustness testing.
Post by: Metermeister on November 27, 2017, 07:17:26 pm
I like both your style. His video is informative in more different way than yourself. It's good that we have many reviewers our field needs them. Electronics in Europe is on the decline.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 01, 2017, 03:26:21 pm
I did ask him to run his own test on the Keysight meter.   This one is 2 years old and gets 10s of thousands of cycles yearly. 

https://youtu.be/_EQdxZK0yHw
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 01, 2017, 03:50:50 pm
When he grabs it and twists the knob it doesn't sound very clicky, not like in your "intro" video.

Would it kill him to open it and take a look instead of just opining?

Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on December 01, 2017, 04:18:04 pm
Finally managed to get the profilometer long enough to do a scan of a 8x8mm patch near the centre of the switch, but the nickel coating is a bit too reflective it would seem. (It registers as lower than the soldermask :) )  Didn't have time to redo it as a dual scan with two modulation thresholds so here's one to begin with:
(https://i.imgur.com/ko4auh8l.png) (https://i.imgur.com/ko4auh8.png)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 01, 2017, 04:56:57 pm
When he grabs it and twists the knob it doesn't sound very clicky, not like in your "intro" video.

Would it kill him to open it and take a look instead of just opining?
He did say tens of thousands of cycles per year, and two years, I would expect it to be a little less clicky.  Maybe he will show you the insides as part of the review he mentioned doing.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 01, 2017, 04:59:59 pm
Finally managed to get the profilometer long enough to do a scan of a 8x8mm patch near the centre of the switch, but the nickel coating is a bit too reflective it would seem. (It registers as lower than the soldermask :) )  Didn't have time to redo it as a dual scan with two modulation thresholds so here's one to begin with:
Thanks for looking at it. You can clearly see the groves.   I'll try to scan part of that H-PAK meter.  With that wiper contact removed, we should get a pretty good contrast between the pads that were cycled and the ones that were not. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 01, 2017, 07:16:45 pm
When he grabs it and twists the knob it doesn't sound very clicky, not like in your "intro" video.

Would it kill him to open it and take a look instead of just opining?
He did say tens of thousands of cycles per year, and two years, I would expect it to be a little less clicky.  Maybe he will show you the insides as part of the review he mentioned doing.
Hopefully. I too agree that he could have shown more of this particular meter, especially because he mentioned having six of these meters and I can't help but wonder if the tens of thousands could be a collective estimate.

Regarding the "clickiness", I notice a slight difference in the feel between my 4yo NOS U1273A and the brand new U1282A - the latter feels more rubbery. At a certain point I had a U1233A but I recall it had a similar feel as to the U1273A.

Of all the meters I have/had, nothing beats the Fluke 179 in terms of robustness feel. At 11:56 of this video I switch both the 179 and the U1233A and you can hear the sound.
https://youtu.be/0asZe5r-hlg?t=11m56s

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 01, 2017, 08:55:41 pm
it doesn't sound very clicky, not like in your "intro" video.
He did say tens of thousands of cycles per year, and two years, I would expect it to be a little less clicky.

There's four clickers altogether so the meter would still click a bit even if three of them are broken.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 02, 2017, 12:53:14 am
One thing to keep in mind is when I life cycle them, the forks are not real tight fit.  The setup has a fair amount of play, or slop in it.  This was on purpose as I am trying to avoid putting the switches into a bind.   Because of this, as the switch approaches the next detent, it's free to snap into place.   If you are holding the meter and turning the knob by hand, the sound level will be dependent on how tight you are holding it.   

I changed the software slightly so when the test is started, the knob is rotated back and fourth as the current is reduced.  The minimum current required to turn the knob is recorded.   I have no idea how this would equate to torque.  The Keysight meter required a fair amount of current to rotate over the Fluke.
Title: Re: Handheld meter electrical robustness testing.
Post by: Paul Moir on December 02, 2017, 05:30:35 am
I'm just wondering what kind of job you have that involves turning the knob on a U1231A every 30 seconds, and why their boss hasn't bothered to optimise their task.
EDIT:  Ha, off by an order of magnitude.  But still every 6 minutes seems like a lot.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 02, 2017, 01:30:05 pm
I'm just wondering what kind of job you have that involves turning the knob on a U1231A every 30 seconds, and why their boss hasn't bothered to optimise their task.

That's not what bosses do.

EDIT:  Ha, off by an order of magnitude.

I'm guessing his numbers are, too. He wasn't exactly rigorous in his video - didn't even take the back off and look.

Mostly he just said "I don't believe it!", I guess that's why he's a boss.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 02, 2017, 03:05:19 pm
I'm just wondering what kind of job you have that involves turning the knob on a U1231A every 30 seconds, and why their boss hasn't bothered to optimise their task.
EDIT:  Ha, off by an order of magnitude.  But still every 6 minutes seems like a lot.

He did post a bit about what they do. It's not just about twisting knobs.  :-DD

I'm guessing his numbers are, too. He wasn't exactly rigorous in his video - didn't even take the back off and look.

Mostly he just said "I don't believe it!", I guess that's why he's a boss.
 

It's not uncommon for people to not buy into the benchmarks I have been showing.  In this case, he went though the trouble to make a detailed video proving what I show is flawed and as a bonus will do a full on review of it later.  He's put out a fair number of technical reviews.  You just have to wait and see. 
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on December 02, 2017, 03:17:25 pm
Rotating the switch is part of accelerated life testing and what that means.  You have to prove your model represents real life otherwise skeptics can raise questions.  In toto Joe's video is simply data and viewers need judge what it means.

For mechanical models, if the test cycles generate heat, failure can be premature, because heat generated from friction has to be added to the model projection, as real life usage have periods of long downtime, consider as work only 8 hours of a 24 day as well as real life environmental considerations, field users in Canada are exposed to colder conditions than field users in Florida etc., UV exposure, humidity etc., which affects plastic rate of failure.

If the video data true as quoted below, and a cal certificate is part of the operational costs, the cost of mentioned calibration is high, it even pays to buy a new meter with papers rather than send it out for calibration.  It makes the Keysight meters more attractive and economical with an expected working life limited by the calibration date, at which time its replaced, regardless of wear.


I did ask him to run his own test on the Keysight meter.   This one is 2 years old and gets 10s of thousands of cycles yearly. 

https://youtu.be/_EQdxZK0yHw
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 02, 2017, 04:58:40 pm
I would guess skeptics will be skeptics no matter the amount of data or how it is presented.  Did we go to the moon, is the Earth really flat, did man  make dinosaur bones and bury them to dig up later.  The best I can do is fully disclose what it is that I am doing during these test and as you you wrote, let the viewers determine what value it has to them.  I can't agree with you more that if I were working for a design/manufacture and our goal was to make a model to determine the life of a new product, this is not a trivial thing to do.   That's far outside the scope (and budget) of anything I would ever attempt at home.     
 
I have mentioned a few times now that during my very first attempts to sort out this test, I cycled one fast enough that the heat indeed caused the plastic to yield.  The few I have looked at do not seem to build more than a couple of degrees when cycling them in the three to five second range.  Beyond the real life conditions you mention, for my own use the meters can get exposed to some pretty bad chemicals as well.   Others have also mentioned the connector failure rates.  Someone posted about the leaking batteries causing early failures as well.   

Based on my own experience, I doubt many companies will opt to have an outside cal house generate reports as part of their calibration cycle for their handheld meters. I would assume from his video they do this for every meter on a schedule as part of their ISO but I have no clue what they gain by tracking the drift of their low end handheld meters.   
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on December 03, 2017, 11:38:31 am
I see it also many small functional faults add up to big ones, as the 'small' ones show lack of attention to detail particularly in a functional item like choice of transient protection device.  By itself it many mean nothing, e.g. the switch failure, but if you look closer you'll see other issues not just in one model, but probably in the whole model line. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 03, 2017, 11:57:48 am
I would guess skeptics will be skeptics no matter the amount of data or how it is presented.  Did we fake the moon landings, is the Earth really flat, did man make dinosaur bones and bury them to dig up later.

I could come up with a label for people who believe those things but it wouldn't be "skeptics".
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 03, 2017, 05:42:25 pm
I see it also many small functional faults add up to big ones, as the 'small' ones show lack of attention to detail particularly in a functional item like choice of transient protection device.  By itself it many mean nothing, e.g. the switch failure, but if you look closer you'll see other issues not just in one model, but probably in the whole model line.

Agree.  If the Gossen I looked at for example was only sensitive to RF, I would consider looking at another.  The reality is the meter has several problems and the company's poor communications have cemented their place.   It just takes too much of my time to look at them in the depth I have been.

I would guess skeptics will be skeptics no matter the amount of data or how it is presented.  Did we fake the moon landings, is the Earth really flat, did man make dinosaur bones and bury them to dig up later.

I could come up with a label for people who believe those things but it wouldn't be "skeptics".
Label me as you like but I am a skeptical of using a resistor to evaluate a meters overall performance.   :-DD

...
I started looking at a new meter and am planning to just make one video for it.   It now has a little over 24 hours of cycle time on the rotary switch.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 05, 2017, 04:59:53 pm
The mystery and the suspense are killing me!  :-X
Title: Re: Handheld meter electrical robustness testing.
Post by: lem_ix on December 07, 2017, 11:26:53 pm
I did ask him to run his own test on the Keysight meter.   This one is 2 years old and gets 10s of thousands of cycles yearly. 

https://youtu.be/_EQdxZK0yHw

Claims you need a process to comment on something yet rambles on without one of his own. In my old uni robotics club there was a 5$ meter that lasted for several years of student (ab)use and international tool box travel. Doesn't exactly make it a great and safe meter. Keysight may have some great products but that doesn't make them s**t gold. To be honest their whole push into the DMM market seems poor considering Fluke is their opponent. The only way to win against them is to give a lot more for the same/less amount of $. More on topic just keep blowing up those meters and play with the remains, for those that want to watch the relevant info is there.

Also Thanks for all the vids :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2017, 05:06:49 am
I did ask him to run his own test on the Keysight meter.   This one is 2 years old and gets 10s of thousands of cycles yearly. 

Claims you need a process to comment on something yet rambles on without one of his own. In my old uni robotics club there was a 5$ meter that lasted for several years of student (ab)use and international tool box travel. Doesn't exactly make it a great and safe meter. Keysight may have some great products but that doesn't make them s**t gold. To be honest their whole push into the DMM market seems poor considering Fluke is their opponent. The only way to win against them is to give a lot more for the same/less amount of $. More on topic just keep blowing up those meters and play with the remains, for those that want to watch the relevant info is there.

Also Thanks for all the vids :-+
Glad you are enjoying the the videos.  I have a fair amount of HP equipment and bought two of their bench meters many years back new.  Both of these have never giving me any problems.  I would buy another bench meter from Keysight but I don't see running another one of their handheld meters.       

Most people that have been following along will know I basically test all the meters the same.   I suspect he was just new to it all and felt the need to chime in without watching.  Funny he felt the need to make a video after I called him out.  People in general don't like seeing the products that they purchased perform poorly.   They need to justify their choices which I assume is also partly why he made the video.  The best part was where he talks about me repairing the meter.   That was pure gold.   Removing the contact that rides over the damaged area of the circuit board is not what I would consider a repair.   I'm pretty sure most people who watch my videos would know that. 

If you like seeing sparks, I have been working on a new review you may enjoy.   So stay tuned.   
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on December 08, 2017, 06:17:10 am
People in general don't like seeing the products that they purchased perform poorly.   They need to justify their choices

Yeah, funny that. I own several Keysight handheld DMMs. As with any tool, it's good to know what they're poor at as well as what they're good at.

Quote
If you like seeing sparks, I have been working on a new review you may enjoy.   So stay tuned.

I shall, as always. :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2017, 10:48:55 am
Harbor Freight's CEN-TECH 95670, the rebranded E0SUN EM129 automotive meter. 

https://youtu.be/Z2Tx0smuu8U
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 08, 2017, 01:33:23 pm
Most people that have been following along will know I basically test all the meters the same.   I suspect he was just new to it all and felt the need to chime in without watching.  Funny he felt the need to make a video after I called him out.  People in general don't like seeing the products that they purchased perform poorly.   They need to justify their choices which I assume is also partly why he made the video.  The best part was where he talks about me repairing the meter.   That was pure gold.   Removing the contact that rides over the damaged area of the circuit board is not what I would consider a repair.   I'm pretty sure most people who watch my videos would know that. 

Was that the actual "response" video or is there more to come?

When you mentioned he was working on a "response" video I expected a video with an actual actual response. The one posted here just seemed like a precursor to the real thing.

Say it ain't so.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2017, 01:54:42 pm
Most people that have been following along will know I basically test all the meters the same.   I suspect he was just new to it all and felt the need to chime in without watching.  Funny he felt the need to make a video after I called him out.  People in general don't like seeing the products that they purchased perform poorly.   They need to justify their choices which I assume is also partly why he made the video.  The best part was where he talks about me repairing the meter.   That was pure gold.   Removing the contact that rides over the damaged area of the circuit board is not what I would consider a repair.   I'm pretty sure most people who watch my videos would know that. 

Was that the actual "response" video or is there more to come?

When you mentioned he was working on a "response" video I expected a video with an actual actual response. The one posted here just seemed like a precursor to the real thing.

Say it ain't so.

I have no idea.  I watched the three mentioned and the first one was more than enough for me personally.  The way they were spouting off, I was really expecting more from them.   Maybe the meter tied to a rope pulled behind the boat test or   what about the meter tied to a rope and pulled down the stairs or dropped?  Now that's entertaining.   :-+   I would just check their channel or subscribe if you are interested in seeing more of their content. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 08, 2017, 02:39:45 pm
Maybe the meter tied to a rope pulled behind the boat test or   what about the meter tied to a rope and pulled down the stairs or dropped?  Now that's entertaining.

A really comprehensive test suite would also include the snow test and the dropped off the roof test.

Oh wait, it looks like their 'channel' had a new video uploaded in the last 24 hours. I might watch it later so see how thorough they are.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 08, 2017, 09:59:27 pm
Joe, another great video. The only thing going for this meter is the mechanical robustness of the rotary switch. Everything else is pretty terrible... :(

I liked the chemical test at the end.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 09, 2017, 12:13:52 am
Message removed, see below...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 09, 2017, 01:03:03 am
Joe, another great video. The only thing going for this meter is the mechanical robustness of the rotary switch. Everything else is pretty terrible... :(

I liked the chemical test at the end.

I have a few friends who also liked the chemical test as well.  I've damaged a few this way over the years and know of others who have as well.  The one used Fluke 97  I have had some sort of chemical damage as well.  I was out of brake cleaner or I would have tried it.   

$30 for a 2000 count meter that is manual ranging , not TRMS,  has an unfused 10A circuit,  no separate continuity mode so it always beeps in low ohms range,  reads 2 X DC voltage in AC ranges and what gets me is it can't even handle the basic engine signals I would normally use which is really the whole point of buying it in the first place.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 09, 2017, 01:36:16 am
I watched the three mentioned and the first one was more than enough for me personally.  The way they were spouting off, I was really expecting more from them.

I just watched the 'review' video. Lots of talking and reassurances, strangely light on facts.

I did learn a couple of things though:

..........

Overall I'm just perplexed by this video. What exactly was the point of it? He likes his Agilents? :-//

Footnote: I feel slightly bad criticizing. My own videos are far from perfect or in-depth and deeply knowledgeable like Joe's are, he's free to poke fun at them if he wants to (just like Joe does). I wouldn't have said anything except that his video is supposedly aimed directly at this thread.

 :-DD  Well, I want to personally thank you for taking the time to sit through it and posting a summary.  If it was anything like the first two, it was longer than it needed to be and I commend you for making it all the way through.   

He was fine trying to shoot holes in my videos until I called him out.   I assume the point would have been to show how my video was flawed by repeating the tests on a second meter.  It sounds like he failed to convince you.   After seeing the SANWA videos, I'm not too surprised to hear he would not show the insides.  He may just not feel comfortable doing something like that.   

He's aware of the EEVBLOG site and is certainly free to join the discussion if he feels he has something to add.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Metermeister on December 09, 2017, 03:33:51 am
 :palm: I think is very sad to criticize another reviewer. I'm bipartisan. I feel no obliged to camp in any one particular tent. Im grateful others can review hardware no matter how good or bad presentation may be. I did learn more from his video than Joes. JOE is very thorough on teardown and input protection but very lack on meter specifics.We should respect everyone. And if think you can do better than best show.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 09, 2017, 09:48:42 am
:palm: I think is very sad to criticize another reviewer.

Me, too, but this "review" was supposedly a smackdown aimed directly at this thread so I consider it fair game. It's not like I called him names in the Youtube comments section or anything.

You make say, "Stick to the facts, not opinions", but there really weren't any. Even the 'informative' parts were a shambles, eg. the part where he showed us how to turn the music off took him three or four attempts before he actually managed it.

PS: Did you watch it?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 09, 2017, 10:01:03 am
Message removed, see below.
Title: Re: Handheld meter electrical robustness testing.
Post by: Metermeister on December 09, 2017, 02:08:05 pm
Me thinks you are wrong. He could have edit the meter setup but chose not to, I prefer that honesty. He demonstrated trigger hold which I had no idea existed with such cheapmeter. I say it again..easy to live in glass house but not if you throww stones. I embrace all reviewers is not easy to do I am sure. :phew:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 09, 2017, 02:26:46 pm
:palm: I think is very sad to criticize another reviewer. I'm bipartisan. I feel no obliged to camp in any one particular tent. Im grateful others can review hardware no matter how good or bad presentation may be. I did learn more from his video than Joes. JOE is very thorough on teardown and input protection but very lack on meter specifics.We should respect everyone. And if think you can do better than best show.

I've received some very helpful criticism, then again the vast majority is more on the trolling level as I suspect they lack the technical background,   "Cat is spelled with a "C" not a "K" you idiot".  Anymore, I typically just flush the trolls and move on.   There have also been cases where the criticism was based on a lack of understanding and many times both people walk away being better.  A recent example was a few people were questioning the how I was presenting the data I collected.  I assume there are others so I changed how it was being shown to help clarify.   Pointing out that I should have used the HOLD function when doing side by side comparisons and changing the white balance is all very helpful feedback.   The content improves because of this.  Of course I am not implying that I act on all the feedback I receive. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 09, 2017, 02:29:16 pm
Me thinks you are wrong. He could have edit the meter setup but chose not to, I prefer that honesty. He demonstrated trigger hold which I had no idea existed with such cheapmeter. I say it again..easy to live in glass house but not if you throww stones. I embrace all reviewers is not easy to do I am sure. :phew:

Good point.  Could you please provide a link to your reviews?  I am interested in seeing them.  Thanks.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 09, 2017, 02:49:51 pm
Me thinks you are wrong. He could have edit the meter setup but chose not to, I prefer that honesty. He demonstrated trigger hold which I had no idea existed with such cheapmeter. I say it again..easy to live in glass house but not if you throww stones. I embrace all reviewers is not easy to do I am sure. :phew:
As Fungus have said, the specific videos were done to counteract a claim presented at joe's tests - the lack of a fundamental scientific method reduces the value of their own videos and therefore the criticism is warranted.

Despite, blank statements like yours to "embrace all reviewers" only shields them from receiving *polite* and *founded* criticism that could improve their experience. Content producers *live* in a glass house and can throw pebbles here and there from time to time - nothing of concern when you also take as part of life that you will have to clean the occasional shattered glass on the floor. I have experienced that myself a few times as youtuber and *many* times in life.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 09, 2017, 08:12:59 pm
I've removed my earlier comments purely one the grounds that he doesn't appear to be around to defend himself, it doesn't feel right to say that stuff in his absence. I'll be happy to say it to his face if he starts posting messages here.

Basically he doesn't appear to know much about multimeters (eg. the difference between latching/non-latching continuity testers) or anything about testing methodology (his video is in no way a rebuttal of joe's).

A rebuttal video would at least have taken apart his "old" meter to inspect it for cracks in the switch mechanism as seen in joe's video. That wasn't done.

Mostly the video is a waste of time, you won't learn anything by watching it, my opinion of Agilent meters was lowered by watching it.

The only thing the meter appears to have going for it is a cal certificate but he appears to lend far to much weight to that, eg. does the certificate still have any legal weight if the meter falls on the floor? I'm sure Joe could invalidate that certificate in seconds.

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 10, 2017, 10:42:12 am
There is a possible flaw in joe's testing of the Agilent. The dial may be turning slowly enough not to heat up the PCB but it might be fast enough to build up heat in whatever plastic Agilent is using in their clickers.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 10, 2017, 03:26:14 pm
There is a possible flaw in joe's testing of the Agilent. The dial may be turning slowly enough not to heat up the PCB but it might be fast enough to build up heat in whatever plastic Agilent is using in their clickers.

With 100% certainty, rotating the switch at any speed will build heat in the plastic parts.   I doubt the few degrees the plastic changes would be enough to have an effect.  Maybe I just happened to find a mechanical resonance.   The other parts in the meter are fine.  I wonder If I could buy a few of the springs to run some different checks on them.  They may even use a different material now.  Hard to say.  Too bad Keysight has no interest in joining or we may actually learn something. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 10, 2017, 03:59:06 pm
...
The only thing the meter appears to have going for it is a cal certificate but he appears to lend far to much weight to that, eg. does the certificate still have any legal weight if the meter falls on the floor? I'm sure Joe could invalidate that certificate in seconds.

There is not much to validate or invalidate.  Every company will have different requirements and procedures.   Over my career,  there are often cases we will have equipment that is not calibrated.   Then there are cases where we calibrate more often.  It really depends but it's always documented.   Handheld meters do not cost near as much as some of the equipment we have under control.  I am not aware of one case where we have had a report generated for a handheld meter.  These are normally checked for cal on an annual basis so any included cert really means nothing beyond if we wanted to track the drift, which we would not do.  It's in or out.   If its out, it gets repaired and or aligned and calibrated.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Metermeister on December 10, 2017, 06:27:10 pm
>>>>>Mostly the video is a waste of time, you won't learn anything by watching it, my opinion of Agilent meters was lowered by watching it.
>>>>>or anything about testing methodology (his video is in no way a rebuttal of joe's)

 i do not agree. 95% meter video reviews have no methodology as you say. They mostly unique and individual and that is okay.
No one claims expert on subject (at least very few). In my country electronics is highly priced so all information is gainful and any insight is good.
Please stop being negative as there is positive in all things. I have seen much worse and much better videos but that is not relevant.
I actual did learn by his video and becuase of it I buy this meter (now waiting for shipping) becuase it does what I need and this review help me choose so all things are unique to each person needs. It seem good price and quality. Even joes last video show this meter can handle lot of abuse and still be good. :horse:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 11, 2017, 05:43:02 am
I've been thinking about upgrading my home temperature chamber (meat packing box) to include cooling.    I had a few old Peltiers from back in the mid 90s.  One is about 60mm square.  No idea on the brand, part number or specs.   Made up a heatsink to try it out.   With 10Wish, small sink reaches 12.7C and the large about 38 with the fans off.   At 50W and the large fan on, it reached -12 open air.   The handheld meters are not much of a load and I have no need to ramp it very quickly.  I'll see about mounting it the box and give it a try. 
Title: Re: Handheld meter electrical robustness testing.
Post by: HalFET on December 11, 2017, 07:06:58 am
You can pick up a temperature controller for PLCs of aliexpress quite easily.  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on December 11, 2017, 12:56:43 pm
I've been thinking about upgrading my home temperature chamber (meat packing box) to include cooling.    I had a few old Peltiers from back in the mid 90s.  One is about 60mm square.  No idea on the brand, part number or specs.   Made up a heatsink to try it out.   With 10Wish, small sink reaches 12.7C and the large about 38 with the fans off.   At 50W and the large fan on, it reached -12 open air.   The handheld meters are not much of a load and I have no need to ramp it very quickly.  I'll see about mounting it the box and give it a try.

My 50W Peltier chamber gets about 17-18degC below ambient, so maybe 6 degC at best in the lab
Could do with better insulation though, but it's already pretty decent.
https://www.youtube.com/watch?v=AI0Q6-h3EGU (https://www.youtube.com/watch?v=AI0Q6-h3EGU)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 12, 2017, 01:51:14 am
Not too bad.   I was thinking about a single stage desktop ice maker depending how my meat packing box works out. 

Cut out a section of Pyropel for a gasket and sealed it with silicone.   The packing box is roughly 60mm thick.  I cut a few channels for the air and will add insulation into this area.   With no load, the old heatsink resistors and fan are inside for some thermal mass but the secondary box removed to get some idea on ramp rates.  Slow, very slow.   

It seems to hold at zero with 30W.  input.   One sensor is near the center, the other in a lower corner.   The small fan does not do a great job but there is a lot of space in that box right not.  The largest thing I have ever put inside it was that Gossen meter so I plan to add more insulation.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2017, 01:03:54 am
Ramping the box from 22C to 5C then to -5C.  The X-axis is in seconds.  I have not tried to tune it as I plan to add more insulation. 

A)
Red is the temperature
Blue proportional term
Green intergral term
Yellow is the error

B)
Only showing the temperature
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2017, 01:38:09 am
Cut up some of that foamed packing out of a shipping box for insulation.  This is a much better size for what I use the box for.   There is plenty of room for the Gossen to sit on it's side and still get air flow around it.   Making one more ramp with it now to see if it improves things.   Afraid with a large thermal mass like the Gossen, it won't help the ramp times but it should at least hit -5.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2017, 03:32:01 am
Ambient to -10C.   About 1 deg overshoot without tuning it.    Regulation is well within a tenth.   Time to see how low it will get. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2017, 03:59:42 am
Almost -15C  but I doubt it would hit this in the summer with the same power fed into it and the only load it has it the fan.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 13, 2017, 11:29:42 am
Thanks for sharing your work, Joe. I suspect one of the good things of having such slow ramp is to avoid condensation. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2017, 04:42:58 pm
I may need to add a drip pan. 

Ran some wires into the box along with a K type.  I stuck it inside of that low end automotive meter.   

I like both the Brymen 869s and UNI-T 181A two temperature inputs.  I use this fairly often on the 869s.  I don't have the cable for the Brymen so I though I would use the 181A to collect the data.  It seems to work except I can't seem to get it to plot both temperature inputs.   It at least seems to record them.   Of course the battery is low and it needs to be recharged because of it's non-standard battery and you can't charge it while you are using it.  Too bad, it could be a really nice meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2017, 09:50:02 pm
Had some time to waste while the 181A is charging up,  so I went ahead and glued the insulation into the upper section.   The battery finally died on the Brymen as well.  I keep meaning to put a good battery in it but I keep damaging meters so there seems to be an endless supply of cheap batteries.   :-DD     Won't be much longer and we can give it a go, maybe another day and the battery should be charged.. 
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on December 13, 2017, 11:20:42 pm
Had some time to waste while the 181A is charging up,  so I went ahead and glued the insulation into the upper section.   The battery finally died on the Brymen as well.  I keep meaning to put a good battery in it but I keep damaging meters so there seems to be an endless supply of cheap batteries.   :-DD     

Yours is probably one of the few labs in which the batteries consistently outlive the meters they came with.   :-DD




Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2017, 12:56:57 am
Starting out, the three sensors read well within 1 degree.  The one K-type sensor came with that last meter.   I set the 181A to log every second.   

I used LabView to plot the data rather than Excel.  5471 seconds or about an hour and a half.   The actual air temperature is faster.  Again, one TC is taped to the LCD and the other inside the meter.  Both will lag a bit.  This is also why the one stuck to the LCD does not dip below when it undershoots.   The meter is a fair amount of thermal mass.    Looks like the half degree delta in the two K types tracks flips but I was not very careful to make sure things had stabilized before starting. 

It could use an LED light and a camera for looking at things like meters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on December 14, 2017, 05:14:05 am
Had some time to waste while the 181A is charging up,  so I went ahead and glued the insulation into the upper section.   The battery finally died on the Brymen as well.  I keep meaning to put a good battery in it but I keep damaging meters so there seems to be an endless supply of cheap batteries.   :-DD     

Yours is probably one of the few labs in which the batteries consistently outlive the meters they came with.   :-DD

 :-DD True. First I've heard of such a problem.
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on December 14, 2017, 05:42:06 am
Had some time to waste while the 181A is charging up,  so I went ahead and glued the insulation into the upper section.   The battery finally died on the Brymen as well.  I keep meaning to put a good battery in it but I keep damaging meters so there seems to be an endless supply of cheap batteries.   :-DD     

Yours is probably one of the few labs in which the batteries consistently outlive the meters they came with.   :-DD

 :-DD True. First I've heard of such a problem.

I chalk it up to terrible luck, myself.  :-DD


Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2017, 03:05:34 pm
I let the 181A charge all night and it finally finished.   It needs a thicker case with AAA cells.   

Looking at boroscopes.   Most claim they are waterproof and some have operating temperatures of 0 - 80C.  They also have the LEDs built in.  This may be the way to go when testing meters that can't log remotely.   I also added a USB3 extension cable to the mix.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2017, 05:40:56 am
I placed all three sensors next to each other and then cycled the packing box.  Basically I wanted to see how well the three sensors track before moving on.  This is the UT181A software showing the various ramping.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2017, 05:47:09 am
What I've done here is taken the data from the 181A software along with the data I collected from the control program and overlaid them.  Both the 181A and the PC were collecting data at 1 second intervals.   The small spike in the 181A near 5 deg. C is from me wrapping the meter in a towel. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2017, 06:04:56 am
I let the packing box settle at 60 C for a half hour to show the stability.  Again, there is no load in the chamber but I doubt a meter is going to present much of a load anyway.    I then drove it back down to 0 and again let it settle.  It's not as stable at the colder temperatures but more than good enough for what I plan to use it for.   

Now I just need to get a camera for inside and we can give it a try on that ALLOSUN or my UT90A meter.   It's getting to be colder here.  Maybe we can do some snow tests as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2017, 08:30:24 pm
Time to do some load testing with the meat packing box.   Most of what I have used this box for has been less than 1W.   Most the the meters I have looked at would not be much of a load as long as they were not measuring high currents.   Even then, 20A and a 0.01 ohm shunt is about it (with the UT61E I modified). 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 16, 2017, 01:06:17 am
Red showing the temperature with various stepped loads. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 16, 2017, 01:23:35 am
I started out at 5C, let the box stabilize, then applied a 2.4 Watt load and watched the response.  Next, I removed the load and let it settle.   I tried 14 Watts but the box just can't remove that much heat so I dropped it to 6.5 Watts.   Looking at the I term, this appears pretty close to the limit at this temperature. 

Next I took it to 50C and again let is stabilize.   I then added the 6.5 Watt load and waited for it to settle.  Then I applied 14 Watts.     

I then applied 23.6 Watts which was more than enough to heat the box without the peltier.  I have a window comparator that monitors the error and will change the polarity if the temperature exceeds 5 degrees.   At 55C, it switched and starts to cool.  There is some undershoot.  Then I remove the load and again at 45 it changes polarity and starts to heat and overshoots. 

Camera is next. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 16, 2017, 07:42:09 pm
Before getting my meat packing box, this was my thermal chamber.  Shown here in 2003 as I am sorting transistors for the antique Tektronix current probe.   I wrote RAP about repairing it and sent him pictures of the test fixture knowing he would have some good advice.   

Quote
"You could ask Fairchild if they sell the 2N3906 and 2N3906 chips in TO-18. I bet if the military wanted to buy 100 of these for $30 each, they could get them just fine,but, how much AUTHENTICITY do you want to pay for?

Best wishes. / rap"

The UT181A is now inside the container.  I've added the ability to run a profile.   I've looked at this meter in the past and it was the most stable out of the ones I have looked at.  Again, it could be a very nice meter with a few small changes.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 17, 2017, 12:10:28 am
Some time ago, I had placed a few meter into a temperature chamber and let them settle at -20 and 60C, noting the displayed value.  The UT181A was effected the least of the meters I looked at.  The UT61E was pretty poor.  Later I did a video where I compensated it using a resistor and diode.   

Today, I tried to repeat the test using the meat packing box and the UT181A.   The first thing I found is I can't drive the temperature below -4 with the 181A inside.  Even after the backlight turns off.  But they have the crazy battery in there for a reason.   

UT181A_0_50C.png shows the output of the UT181A (blue) captured with their software and the ambient air temperature.  I started out at 0, then increased it 10 degrees every half hour.   

UT181A_0_50C_1mv.png shows the zoomed in reported output.  No big surprises and it basically just does the same thing it did before, hardly move.   An impressive meter if it had a little help.    Well it's back to the charger for it.    :palm: :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 19, 2017, 12:12:32 am
I mentioned I had repaired the Kasuntest and Harbor Freight free DT830 after I had life cycled their switches to save them for future tests.  The new ESD gun has never damaged a meter since I started using it.  Knowing the grill igniter had damaged a DT830 in the past and the gun puts out a far more realistic waveform, it seemed only fitting to repeat this test.    No plans for the Kasuntest yet but I am sure I will come up with something.   

https://youtu.be/E5aj4guPbZQ
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2017, 12:42:20 pm
This one is for the Brymen fan boys.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Russ on December 20, 2017, 03:17:51 pm
How did the Brymen perform in the rotary switch testing?

Russ
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 20, 2017, 09:44:42 pm
How did the Brymen perform in the rotary switch testing?

Patience. If "cycle0" was only 3 hours ago then it's probably not finished yet.
Title: Re: Handheld meter electrical robustness testing.
Post by: Russ on December 20, 2017, 10:56:26 pm


Quote from: Fungus on Today at 08:44:42 AM (https://www.eevblog.com/forum/index.php?topic=48998.msg1380186#msg1380186)


>Quote from: Russ on Today at 02:17:51 AM (https://www.eevblog.com/forum/index.php?topic=48998.msg1379891#msg1379891)
How did the Brymen perform in the rotary switch testing?



Patience. If "cycle0" was only 3 hours ago then it's probably not finished yet.

Thanks. I didn’t realize it had just started.


Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on December 20, 2017, 11:47:25 pm
Hmm.., don't know why he'd waste the tracks on his best "go to" meter.. Perhaps Gossen sent him a new Ultra M248C for a Christmas review?
You know the deal, no strings, magnets or shields attached  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2017, 03:55:04 pm
That picture was taken at the start of the test.   It takes days to run it. 

After a few days, some of the the tubing has worn.   I like this stuff as it is very soft life a human's fingers. 

Hmm.., don't know why he'd waste the tracks on his best "go to" meter.. Perhaps Gossen sent him a new Ultra M248C for a Christmas review?
You know the deal, no strings, magnets or shields attached  :)

Really, you after two years of running meters to failure, you don't why?  That's good because I am at least not alone.   

I would be amazed if Gossen just posted or dropped a private email with an update. Do you think Keysight would respond faster about their detent spring?   :-DD     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2017, 05:03:59 pm
I have seen where the Teslong NTC camera is rated to operate from 0 - 80C.   

Temperature/humidity monitor is tossed into the meat packing box and I ran it from 0 to 50C without any problems.  Also shown is a meter inside the box with the lid closed off to give you an idea how it would work.  The camera presents a bit of a thermal load but it does not take much light to see the meter.  Turning down the brightness helps a lot.   

Not a bad setup for basically made from junk.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 24, 2017, 04:11:24 am
I don't know if you want to look at another Brymen, but the BM315 and BM319 are automotive meters.

The Brymen BM319s automotive handheld meter Christmas Special.  Travel safe and have a Merry Christmas!

https://youtu.be/uY6ZcINF7L0
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2017, 11:24:44 pm
With so much speculation about the life of the BM869s, I think it's time that we add some data to the mix.   Consider this my new year's gift to all of you Brymen fans or anyone wanting to see this test ran. 

While running the test, I had some questions about the meter and my results that I wanted to run by Brymen and have included their responses as well. 

The video is in the process of uploading so look for it shortly.   

Have a Happy New Year!!


https://youtu.be/bs5n3a__Yq0
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on December 29, 2017, 05:11:15 pm
Thanks joe, nice to see a manufacturer who is looking to improve the product where it counts. Making sure the stuff will work well after the warranty period, making sure the parts are good value for money, along with making sure it will survive the typical use environment without issues. no wonder we all like those meters and the whole related family of them. Not your typical hit or miss manufacturer, but good value on all the range.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 29, 2017, 05:48:04 pm
Thanks joe, nice to see a manufacturer who is looking to improve the product where it counts. Making sure the stuff will work well after the warranty period, making sure the parts are good value for money, along with making sure it will survive the typical use environment without issues. no wonder we all like those meters and the whole related family of them. Not your typical hit or miss manufacturer, but good value on all the range.

Strange but I agree with all your points for a change.   :-DD :-DD   I have been really impressed with their whole attitude.     

Hopefully my comments about the lubrication make it clear that this is not a trivial subject to cover.  I've though about running one of the lubricated Fluke meters to see if it does as well as that 17B+ did with dry contacts.

I noticed a small mistake in that last video. 

Data files are named using the following format:
BRAND_MODEL_LUBE_STATUS
Switch Contact LUBE: D - Dry or no lubrication, L - Lubricated
Meter Status: N- New, U - Used, D - Damage to switch area

If you look at the file name  "BRYMEN_BM869s_D_U_48_Dec21_2017", the meter is obviously brand new.  I have since corrected this.
Title: Re: Handheld meter electrical robustness testing.
Post by: Russ on December 29, 2017, 07:30:30 pm
It looks as if the Brymen performed quite well.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on December 29, 2017, 09:54:47 pm
Nice work on the video and testing Joe...
So Brymen held it's promise of a decent product with decent price... Good to know..
Of course, one instrument is not good statistical sample, but it shows a trend..
What I like most is manufacturer standing behind it's product and customers...
Fact that they weren't afraid of testing, and open communication is very telling..
There are some "very fancy" manufacturers that could learn a thing or two from them...

Regards,
Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: Russ on December 29, 2017, 10:00:24 pm
Maybe worth watching?

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F372176745939 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F372176745939)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 29, 2017, 10:06:51 pm
Joe, thanks for another excellent test. My past experience in contacting Brymen is nothing but perfect, and I am really glad to see them being very open and standing by their product.
To me, your tests only give reassurance about the leading brand and a quite formidable competitor of the portable meters marketplace.
Title: Re: Handheld meter electrical robustness testing.
Post by: lem_ix on December 29, 2017, 10:19:35 pm
Thanks for the great test Joe. With the help of your videos and accumulated experience here on the forum, at least in my eyes Brymen is definitely an alternative to Fluke in Europe where their prices are overly inflated. (Fluke 87 ~585€ vs 265€ for 869S locally, VAT included)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 29, 2017, 11:30:32 pm
Someone had pointed out the different shades of the older and newer Brymen's LCD.  Note the plastic case and rubber boot on my old one are also a little lighter.   I expect this is from the sun.  The LCD I am not so sure.  It does have that Belkin protective film over the lens and I did polish this one after I had added a few personal marks to it.   

Pure luck on the shot.  They move around a bit. 
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 30, 2017, 12:21:04 am
I mentioned I had repaired the Kasuntest and Harbor Freight free DT830 after I had life cycled their switches to save them for future tests.  The new ESD gun has never damaged a meter since I started using it.  Knowing the grill igniter had damaged a DT830 in the past and the gun puts out a far more realistic waveform, it seemed only fitting to repeat this test.    No plans for the Kasuntest yet but I am sure I will come up with something.   

For the ESD pulse generator, are you are using a cap+resistor discharge, like the 330R+150pF HBM kind of thing ?
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on December 30, 2017, 09:11:06 pm
Recently there has been some very dry weather in California, and I have noticed that if I walk across the carpet in slippers and then touch something metal I invariably create quite a spark. So what kind of ESD gun am I compared to the fabricated ones? Presumably I am quite a realistic one.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 31, 2017, 12:52:00 am
Recently there has been some very dry weather in California, and I have noticed that if I walk across the carpet in slippers and then touch something metal I invariably create quite a spark. So what kind of ESD gun am I compared to the fabricated ones? Presumably I am quite a realistic one.

It is getting to be winter here and the house is starting to get dry as well.    Yes, what you describe would be one specific realistic event but I doubt you could get it to repeat, pulse after pulse, day after day.  There are so many variables which is why we have standards.  Then the standards change as we learn more.    You could try to measure it and prove it to yourself. 

http://www.emcsociety.org/2010%20Events/ESD%20Presentation%202010%20update.ppt (http://www.emcsociety.org/2010%20Events/ESD%20Presentation%202010%20update.ppt)



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 07, 2018, 10:39:18 pm
That box sure seems big for just two meters.  Perhaps there was something else inside.... 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on January 08, 2018, 09:26:34 pm
Ooh, more goodies!
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on January 08, 2018, 09:59:44 pm
It's time to re-evaluate 121GW :).
Title: Re: Handheld meter electrical robustness testing.
Post by: Russ on January 09, 2018, 01:19:43 am
It's time to re-evaluate 121GW :).

   I’ve already ordered extra probes and 121GW capable fuses.
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on January 09, 2018, 02:03:18 am
That box sure seems big for just two meters.  Perhaps there was something else inside....

The anticipation is killing me. Hope this isn't a vicious tease
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on January 09, 2018, 04:34:08 am
That box sure seems big for just two meters.  Perhaps there was something else inside....

Another item to administer stress to the victims?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 09, 2018, 05:57:48 pm
It's time to re-evaluate 121GW :).

 :-DD  Not yet anyway.   I don't think we would learn anything new really and my guess is if the problems I saw in the prototype were not corrected, you will be hearing about them very soon.  So just be patient as the masses work their magic. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 09, 2018, 06:02:54 pm
Ooh, more goodies!
:-+

The anticipation is killing me. Hope this isn't a vicious tease
I'm not well known for not following through.  So hang in there for a few weeks or so and you may just see another Brymen on the chopping blocks..     

Another item to administer stress to the victims?
Don't I have enough instruments of death and destruction already?   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on January 09, 2018, 06:12:12 pm
Another item to administer stress to the victims?
Don't I have enough instruments of death and destruction already?   :-DD

It's not an artificial snow machine then...?  :(

Title: Re: Handheld meter electrical robustness testing.
Post by: BroMarduk on January 09, 2018, 06:35:59 pm
I'm not well known for not following through.  So hang in there for a few weeks or so and you may just see another Brymen on the chopping blocks..     

I had to re-read that positive via double-negative a few times for that to make sense...
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on January 10, 2018, 12:47:44 am
Yes, Joe, all ahead FULL.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 10, 2018, 01:02:36 am
Yes, Joe, all ahead FULL.

Those of you that have followed along realize that when I bought the BM869s, it went through the same transient testing as the other meters.  It had survived everything I could throw at it with the new generator.   At the time I was rebuilding the original generator for each test and so I ran the 869s at the same levels I had tested the Fluke 101 at and it was damaged.  In most cases where I did not have a way to run the incremental tests, I have have gone back and repeated the tests using the new generator to find where the meters fail.   I never did this with the BM869s.   So that new 869s may have done fine with the 50,000 cycle test and survived a dip in the creek, it seems fitting that it should be used to repeat the high voltage transient tests.   My plan is to include this test when I run this last meter.   
space bar habit..
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 10, 2018, 04:20:27 am
So much to do with this meter.  Brymen did not send them because they knew I would treat them with kid gloves.  I think it needs the FULL treatment!
Joe correct me if I'm wrong, but something says Bryman's motive is from concern that UEI is soon likely to take a bite out of their sales. I mean what are the odds that UEI may be gearing up to push a lot of 121GW or similar types into the market place this year? And China never sleeps either, so Bryman may be using you (it's fair) to bolster sales on existing stock, while doing R&D on something fresh.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 10, 2018, 01:12:01 pm
So much to do with this meter.  Brymen did not send them because they knew I would treat them with kid gloves.  I think it needs the FULL treatment!
Joe correct me if I'm wrong, but something says Bryman's motive is from concern that UEI is soon likely to take a bite out of their sales. I mean what are the odds that UEI may be gearing up to push a lot of 121GW or similar types into the market place this year? And China never sleeps either, so Bryman may be using you (it's fair) to bolster sales on existing stock, while doing R&D on something fresh.
That's an interesting take on it.  With as many delays as we have seen for the UEI meter, there is no way I could have projected when it was being released and just happen to be talking with Brymen about their automotive meter and then have them arrive in the same time frame.   Perhaps lightages was in on the conspiracy, after all us used to sell Brymen products and he is the one who pointed out they offered an automotive meter.     :-DD :-DD   Sorry,  but I am not buying it or the idea of a flat earth.   I doubt the UEI meter is targeted towards automotive and can't see it competing with the one Brymen provided.   To be clear, Brymen did not reach out to me and open the dialog nor did they ask me to run the BM869 or even suggest it.     

I really would have no idea what UEI's future plans are but assume using the EEVBLOG brand will generate a fair amount of sales for them.  What else would be the motive? 

I would agree that Brymen is most definitely using me as you so put it and I am certainly allowing it to happen.  I will even go so far as to say I requested it.  Showing these test may indeed have some measurable impact on sales but making money has never been my motive for running them.  My interest has always been with how robust the meters were.     

I've obviously looked at the UEI prototype along with a few Brymen products.  Looking at how robust the Brymen products continue to be, I don't think they have any concerns in this area.  There is nothing preventing other companies from contacting me.  If UEI wants to see how their products stand up, I am not apposed to running them.   The snow bury,  fishing, gasoline spilling,  50000 switch life cycle testing awaits.  If we are lucky, maybe we even get  to play with the half cycle simulator.
Title: Re: Handheld meter electrical robustness testing.
Post by: Scottjd on January 12, 2018, 08:53:34 am
I doubt the 121GW will be UEI's choice for an automotive meter. UEI already makes an automotive meter that has better features for the Automotive job. They have a whole line of meter just for automotive. UEI already beats Brymen hands down in specific automotive testing and diagnostics tools and lab scopes.
The automotive one seem to have more features for recording individual cylinders, RPM’s, higher temp readings to 1,370C, Dwell, fuel injector testing timing pulse width, and of corse duty cycle.
http://www.ueiautomotive.com/index.html (http://www.ueiautomotive.com/index.html)

They have been around for while, mostly behind the sceence with HVAC, automotive, and electrical but mostly with clamp meters.
http://www.ueitest.com/products (http://www.ueitest.com/products)

I recall Dave even mentioning that UEI already had a Bluetooth stack and protocol designed that they offered to use with the 121GW, so this tells me they already had a Bluetooth meter. I don’t know why Dave decided to make his own apps when UEI already had all this to start with? UEI already has an andriod and applemios app. The app looks basic but can do a 100ms refresh rate, record, graph, export to CSV, PNG, or JPG, continuous readings.
http://www.ueitest.com/products/dl429 (http://www.ueitest.com/products/dl429)

Maybe this is why Dave went with UEI this time because he wanted Bluetooth as a feature?

Brymen seems to do more handheld DMM’s, some clamps but none for a specific fast or job, eletricla tester, and some insulation test meter to 1kV. But I don’t see them doing any HVAC, gas detection sensors, combustion sensors, specific HVAC, or some other specific tool that UEI make. They have 2 automotive meters, but not any automotive lab scopes that also read ODBII codes,gas and leak detectors/gas anylizers, CO detectors. UEI seems to have more automotive selfie tools, not just an automotive meter.

I see these companies being on two different scales currently. Brymen has a lot of different specific clamps for electricians, general purpose DMM’s, only w automotive meter a no specific automotive testing tools or scopes, 2 insulation tester meter, no HVAC specific stuff. Brymen seems more on the  electrician side of things with a few basic automotive meters, and UEI seems more into specific test equipment for different jobs and just happens to cover electric with the clamps as well.

http://www.brymen.com/Products.html (http://www.brymen.com/Products.html)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 12, 2018, 01:26:19 pm
Hey Scott. I don't have HVAC on my bikes.  :-DD :-DD  A few vents in the helmet and leathers is about it. 

I may try one of UEIs automotive meters to see how it stacks up with the others I have looked at.   So far that Brymen has been the least sensitive to the emissions.   Actually, my BM869s was really stable. 

Agree, I don't see the two companies really being in the same markets.  With so much excitement around the UEI meter, I can see how anything detracting from it may be seen as a conspiracy. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 12, 2018, 02:17:07 pm
I checked out the meters they offer.  The ADM5201 would have been a good one to try.  Both it and the ADM4201 are listed as discontinued at TE.   Their ADM3201 is getting a bit too much like that ESUN meter I looked at. 

The ADL7103 is also listed as discontinued at TE.  Starting to wonder if they make anything.  Maybe the hope is the EEVBLOG branding will save them?  :-DD   They may just not be popular in the USA, like Brymen. 
Title: Re: Handheld meter electrical robustness testing.
Post by: lem_ix on January 12, 2018, 02:26:35 pm
Who knows under which name they're sold under ... Fine/Finest? Klein?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 12, 2018, 03:07:53 pm
I checked out the meters they offer.  The ADM5201 would have been a good one to try.  Both it and the ADM4201 are listed as discontinued at TE.   Their ADM3201 is getting a bit too much like that ESUN meter I looked at. 

The ADL7103 is also listed as discontinued at TE. Starting to wonder if they make anything.  Maybe the hope is the EEVBLOG branding will save them?  :-DD   They may just not be popular in the USA, like Brymen.
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 13, 2018, 12:25:16 am
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD

If I can't find a distributor, as far as I am concerned they may as well be discontinued.  If TE dropped them, I would have to ask myself why.  It could have been anything from lack of sales to poor quality or maybe it really is discontinued.   :-//

LOL!  I am a guppy in the YT ocean.  I doubt anything I show has much of an impact on the T&M world.   But consider that I may be using Brymen to increase my channel to 100GV/m  (gig views/month) so I can sell it.   :-DD     

All seriousness, I can't really explain Brymen's interest in my testing but they do appear to appreciate the feedback I've given them. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 13, 2018, 01:33:25 am
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD

If I can't find a distributor, as far as I am concerned they may as well be discontinued.  If TE dropped them, I would have to ask myself why.  It could have been anything from lack of sales to poor quality or maybe it really is discontinued.   :-//
That is the thing; at the time the product was being sold by other official distributors and TE decided to drop that particular product line or brand. I can't recall if it was the former or the latter, but I kinda recall something about Siglent. Sorry, I don't recall anything further than that.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on January 13, 2018, 02:51:25 am
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD

If I can't find a distributor, as far as I am concerned they may as well be discontinued.  If TE dropped them, I would have to ask myself why.  It could have been anything from lack of sales to poor quality or maybe it really is discontinued.   :-//
That is the thing; at the time the product was being sold by other official distributors and TE decided to drop that particular product line or brand. I can't recall if it was the former or the latter, but I kinda recall something about Siglent. Sorry, I don't recall anything further than that.
One should not discount the other possibility.....that a sales distributorship can be revoked and given to another company. This does add confusion to the marketplace for a while especially if the 'no longer' distributor continues to have a web listing for a brand and range of products and lists them as 'discontinued' which is just BS.
TE in particular up until recently listed the bulk of the Siglent product range and each one had 'discontinued' tacked to the listing but to their credit they've updated that some with no products listed and just discontinued if you hit the Siglent products link.
https://www.tequipment.net/siglent/ (https://www.tequipment.net/siglent/)

Siglent selling rights were given to Saelig.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on January 13, 2018, 04:20:06 am
I doubt the 121GW will be UEI's choice for an automotive meter. UEI already makes an automotive meter that has better features for the Automotive job. They have a whole line of meter just for automotive. UEI already beats Brymen hands down in specific automotive testing and diagnostics tools and lab scopes.

The 121GW is now effectively the only electronics meter UEI make.
The DM393 seems to be the only other one they make, but I think that may also be close to being discontinued.

Quote
I recall Dave even mentioning that UEI already had a Bluetooth stack and protocol designed that they offered to use with the 121GW, so this tells me they already had a Bluetooth meter.

I don't recall ever saying that.

Quote
I don’t know why Dave decided to make his own apps when UEI already had all this to start with? UEI already has an andriod and applemios app. The app looks basic but can do a 100ms refresh rate, record, graph, export to CSV, PNG, or JPG, continuous readings.
http://www.ueitest.com/products/dl429 (http://www.ueitest.com/products/dl429)

We wrote our own app because the UEi one they wrote us was almost a joke. It was very buggy and the UI was straight out of the 1990's.
We thought it would be better to write our own and make it completely open source, and it would be easier than trying to get them to fix the one they had. We already had enough back and forth communications grief with the meter design.
Unfortunately what David2 thought would be fairly easy task of creating an true multi-platform app (from the same code) turned into a multi month nightmare.

Quote
Maybe this is why Dave went with UEI this time because he wanted Bluetooth as a feature?

No, nothing to do with it.
I went with UEi because they said they could do a fully custom meter and were keen.
I recall Brymen not being very receptive of the idea. Maybe it would be different now that they know who I am and how many meter I sell for them.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on January 13, 2018, 04:24:47 am
Joe correct me if I'm wrong, but something says Bryman's motive is from concern that UEI is soon likely to take a bite out of their sales. I mean what are the odds that UEI may be gearing up to push a lot of 121GW or similar types into the market place this year?

The odds are precisely zero.
UEi are not allowed to use the same 121GW case to compete in the same multimeter market as the 121GW, it's in the contract.
They are however allowed (and wanted to) use re-use the 121GW case for another product(s). What that is I don't know.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on January 13, 2018, 04:27:53 am
Who knows under which name they're sold under ... Fine/Finest? Klein?

Finest is now owned by UEi / Kane Test.
The former CEO of Finest is actually the one who was in charge of the 121GW design.

Klein is a related party to the two, they contract UEi to design some of their stuff.
That's actually how the whole 121GW came about - I did that Klein Tools meter test in the mud and the designer contacted me.
I mention about maybe doing a custom meter and he introduced me to UEi / Kane Test.
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on January 13, 2018, 04:51:06 am
What about the feature set? Will they be able to incorporate these same functions in another meter lacking the EEVBlog name?
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on January 13, 2018, 10:34:03 am
What about the feature set? Will they be able to incorporate these same functions in another meter lacking the EEVBlog name?

Contractually, probably nothing really stopping them doing that.
But that would be what is known in the industry as a dick move  :D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 13, 2018, 07:58:15 pm
After surviving 50,000 function switch rotations and going for a swim in ice water,  the BM869s gets set for a round of transient tests.   Will it repeat and survive the new generator like it's predecessor or will it fail like an old 87V?   Stay tuned while we finally find out just how much can Brymen's top of the line meter handle.

Because of the time required to run all these tests, my plan will be to release this on a separate video. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 13, 2018, 08:13:58 pm
Is this going to be after wiping down those contacts?
At 100 rotations per ~300 working days a year, what tech wouldn't have used some IPA within 16 plus years of use?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 13, 2018, 08:38:32 pm
Is this going to be after wiping down those contacts?
At 100 rotations per ~300 working days a year, what tech wouldn't have used some IPA within 16 plus years of use?
That's nothing.  Think about those two people who have posted how they put 10s of thousands of cycles on their meters every year!   In the one case we can be fairly confident that the contacts were never cleaned as they would not take the meter apart to show them in their debunk video.    :-DD 

In all seriousness, if you would have watched the video where I life cycled this meter, towards the very end I mentioned that I took some ProClean to it so we could get a better view of the damage.  I even showed the swabs I used.   Of course, then the meter did some scuba diving and the water was fairly conductive.  So everything had to be flushed out again. 

We know between what levels the first one failed.  That's a pretty wide window if you look at the data.   Somewhere between 5.8 and 13KV.  Which is the whole reason I plan to repeat it.   



Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 13, 2018, 09:49:11 pm
Come to think of it, yes I did see it. So much happened over new-years, guess I've had too many damned "senior moments" to recall..   :)
Title: Re: Handheld meter electrical robustness testing.
Post by: Scottjd on January 14, 2018, 08:31:19 am
I checked out the meters they offer.  The ADM5201 would have been a good one to try.  Both it and the ADM4201 are listed as discontinued at TE.   Their ADM3201 is getting a bit too much like that ESUN meter I looked at. 

The ADL7103 is also listed as discontinued at TE. Starting to wonder if they make anything.  Maybe the hope is the EEVBLOG branding will save them?  :-DD   They may just not be popular in the USA, like Brymen.
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD
I forgot to mark this thread as notify. I’m ised to their boards if you reply to something you automatically get notified. Well, and I miss one email in spam and the notify stops also on this forum.
As for tEquiptment when they decide to stop carrying a product line they mark the, as discontinued. Not the cimlnay making it, but the relationship with TEquiptment and the company is discontinued.
They had a problem, more a disagreement with another company last year that still sells and makes scopes, but they dropped the products off the site, marked as discontinued. Even didn’t finish selling the stock in the mains site. Instead they sold the left over stock on eBay.

I don’t know much about TE personally, but heard a lot twice a week from a close friend. I know they sell Brymen and my close friend had an issue with his meter. It was eventually agreed to be sent in, first they couldn’t find the issue, but he said it was intermittent. Then they lost his meter for a month, then they said they found it and sent him a different one, scratch on the screen, new serial number and different issues with that meter. Finally I told him to reach out to Brymen and he did, Brymen solved his issues and replaced the meter. After listinging to his horror story for three months I decided I would never buy fro TE. The might be a good price for most, but if something goes wrong with a defect they don’t want to hear about it or help. He had to fight with them just to get it sent in for service, and he had to pay the shipping to TE and return shipping back to him.
No thanks, I’ll buy local for better support that honors the warranty for a few more dollars, not worth the little savings. I think after the shipping costs he could have bought local also, and he was without a meter for a few months.
Title: Re: Handheld meter electrical robustness testing.
Post by: Scottjd on January 14, 2018, 08:40:04 am
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD

If I can't find a distributor, as far as I am concerned they may as well be discontinued.  If TE dropped them, I would have to ask myself why.  It could have been anything from lack of sales to poor quality or maybe it really is discontinued.   :-//
That is the thing; at the time the product was being sold by other official distributors and TE decided to drop that particular product line or brand. I can't recall if it was the former or the latter, but I kinda recall something about Siglent. Sorry, I don't recall anything further than that.
Yes, that’s the other company I couldn’t remember. It was Siglent I think the sold off remaining stock on eBay and removed from the main site. I don’t know the details, I’m giessing personal conflict disagreement or contractual agreement. Who knows.
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on January 14, 2018, 08:43:39 am
Crap on a cracker.  I was only kidding when I said the 121GW would save them.

Who said they need "saving"?
Perhaps they just didn't really want to be in the electronics meter business any more and wanted to focus on other markets?
Title: Re: Handheld meter electrical robustness testing.
Post by: Scottjd on January 14, 2018, 10:56:45 am
I recall Dave even mentioning that UEI already had a Bluetooth stack and protocol designed that they offered to use with the 121GW, so this tells me they already had a Bluetooth meter.

I don't recall ever saying that.

Hi Dave, sorry for the late reply. I didn’t set notify on this thread.
I may be wrong, but I believe it was mentioned in the Kickstarter live stream video talking about Bluetooth, but this video is now gone from the Kickstarter campaign, so I could only reference your channels YouTube video that seems to have been edited with a 20 minute difference in overall video time.
I think it was around YouTube’s video mark of 48:08 to 48:50 seconds (or kickstart time stamp 57:07 to 57:59). But their is also 9 seconds of the Kickstarter video missing that was cutout at the end of this topic according to the Kickstarter video time stamp.

Its hard to say for sure since the YouTube video has been edited, and after that 9 seconds from the Kickstarter time stamp is gone at the end of that topic. So I can’t say for sure if it was in these 9 seconds or not, but I remember the whole topic part was about  Bluetooth. The Kickstarter time stamp goes from 57:49 to 57:58.

So I know my memory isn’t the best these days, but I was watching the live Kickstarter originally. Other parts about that live stream stayed with me more then the Bluetooth stuff.  I remember watching the live stream and the comment on your YouTube video at 49:46 about not knowing if a hardware issue will make it obsolete. It made it sound like no one beta tested outside your lab except maybe Joe with his hardware robust testing.
I thought to my self “maybe I should cancel the order now” since I pledged before you started streaming live. I think you said it’s hard to debug your own stuff, and that’s so true.
Just curious, but was it a UEI non-disclosure agreement that stopped you from sending meters out to a few others for functionality and firmware testing? I know you can have beta testers also under NDA’s, I’ve been under two since I started my channel 2 years ago helping find software bugs in products before they are released. After all, I think this might be the first meter UEI built using the ST microprocessor?

But I still took the risk, now I hope UEI doesn’t take long to update the firmware with fixes for some of the issues discovered. If they do a firmware update, will a beta versions be available publicaly for some to test before the final firmware update is release to all?

And I almost forgot, did you pitch them my idea of dumping the EEPROM calibration data to the SD card before any calibration changes are made as a backup, giving the user a restore point if they mess up the calibration? I know you said it was a good idea, but not sure if they will add that to the firmware on the next release or if they have the space for additional code. Or even how often they plan on doing firmware bug fix releases. But this was more of a feature idea that could help cut back on support emails.
Thanks,
Scott
Title: Re: Handheld meter electrical robustness testing.
Post by: nidlaX on January 14, 2018, 11:07:49 am
Just be warned about the "discontinued" status at TEquipment: not long ago I saw one product still in production that was marked as "discontinued" on their website. I would always check with the manufacturer first.

Regarding the Brymen/UEI conspiracy theory, let me throw another one: perhaps they are "using you" to increase their perceived value and be bought by a larger TE brand?  :-DD
If TE dropped them, I would have to ask myself why.  It could have been anything from lack of sales to poor quality or maybe it really is discontinued.   :-//
Silly TE never bothers to distinguish between products that are actually discontinued or those that are dropped for arbitrary reasons such as disagreements over marketing, licensing, etc.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 14, 2018, 01:37:41 pm
If a product is too difficult to buy, I'm not going to go out of my way to hunt one down.
Of course; each to its own. I only found it disingenuous that TE used a term widely adopted in the industry when a product actually ceased to be manufactured. As Dave would say, it was a "dick move".

(...)
One should not discount the other possibility.....that a sales distributorship can be revoked and given to another company.
(...)
Siglent selling rights were given to Saelig.
Thanks for refreshing my memory.
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on January 14, 2018, 02:35:17 pm
I went with UEi because they said they could do a fully custom meter and were keen.

This is really good to know as I presume 121GW then was built very much to your (EEVblog) specifications and not to UEi's.

Sorry if you already made comments/videos about this - but that might have been privileged to the Supporters launch which I do not have access to.

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 14, 2018, 02:40:55 pm
Crap on a cracker.  I was only kidding when I said the 121GW would save them.

Who said they need "saving"?
Perhaps they just didn't really want to be in the electronics meter business any more and wanted to focus on other markets?
It would be strange to find out a company would drop their entire bread and butter product line because they don't want to be in the business only to decided to design and manufacture a custom meter for you.  I can just imagine the story behind it.   While I previously said they may need saving as a joke, you have adding a new twist.
You are right; it would have been strange but not unheard of.
Actually, looking at their page in the US website, it shows only the model 393 as their active "Digital Multimeter" - all others are discontinued. If one looks only from this angle, it looks like they are more interested to be an ODM or are looking for a comeback to the "electronics DMM segment".

We can only wonder...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 14, 2018, 03:41:13 pm
You are right; it would have been strange but not unheard of.
Actually, looking at their page in the US website, it shows only the model 393 as their active "Digital Multimeter" - all others are discontinued. If one looks only from this angle, it looks like they are more interested to be an ODM or are looking for a comeback to the "electronics DMM segment".

We can only wonder...
Maybe it's just one person who is leveraging their previous contacts?  :-DD  Maybe they will contract with Brymen to produce the UEI meter..  :-DD 

Speaking of Brymen, the third meter is getting some time out in isolation, or insulation.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 14, 2018, 11:34:00 pm
Well, at least I know the brand, which is a bit more about the mysterious box than before... :P
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on January 15, 2018, 12:48:14 am
Well, at least I know the brand, which is a bit more about the mysterious box than before... :P

The box was shipped directly from Brymen...what other brand was it likely to be?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 15, 2018, 01:21:51 am
Well, at least I know the brand, which is a bit more about the mysterious box than before... :P

The box was shipped directly from Brymen...what other brand was it likely to be?
Perhaps I missed that post or did not pay attention to a photograph previously posted.
In one of the pictures, there are two Brymen boxes of meters that Joe owns on top of a mysterious cardboard one. I really think it could be anything.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 15, 2018, 01:56:24 am
This meter has lived a long life in a very short time.   If you don't think Brymen knows how to make tough meters, think again!

https://youtu.be/zIKSUqs0Lks
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 16, 2018, 03:35:49 am
I have started life cycling the last Brymen's rotary switch.   Not that 600 cycles means much but in the following, you can see the EM129 and 830B were already past an ohm!  The junk meter was doing better than them.   As you look down at the lower resistance levels we can see the ZT102 is starting to move a little.  So is the U1231A.  Not much but it's there.   Then we get into the next class of meters.... 

Only 57 hours to go assuming nothing goes wrong.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 16, 2018, 12:33:10 pm
A bit over 8000 cycles so far and the the last Brymen is looking pretty good.   Not a real surprise when you consider we are looking at a product built by a company who runs these tests as a practice. 

The top graph is showing all the meters I have looked at, clipping at 50 ohms.  It looks like a big mess so let's hide everything but the Kasuntest, HPAK, Fluke and the two Brymens.   It's not a lot of data yet but just like the transient testing, we are already starting to get a pretty good picture. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Kean on January 17, 2018, 11:46:59 am
Joe, I'm sure it is mentioned somewhere earlier in this thread, but what resistance are you measuring during this switch cycling?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 17, 2018, 01:13:12 pm
Joe, I'm sure it is mentioned somewhere earlier in this thread, but what resistance are you measuring during this switch cycling?

The switch contact resistance.
Title: Re: Handheld meter electrical robustness testing.
Post by: Kean on January 17, 2018, 01:21:11 pm
I imagined as much, but wanted to be sure I wasn't missing something  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 17, 2018, 01:52:23 pm
I imagined as much, but wanted to be sure I wasn't missing something  ;D
I wasn't sure if that was what you were asking.  So yes, the some of these cheap meter's contact resistance goes well over an ohm in a very short number of cycles.  We now know Brymen runs cycle testing but I wonder how many other companies do.   

It's too bad we don't get to see companies put out more videos about their testing.  I would like to see videos showing a handheld meter going through the entire safety and EMC testing.     They could make it live with a chat, Why are you putting 5KV into the meter when it clearly shows it is only rated for 600 volts on the front?  Why are you directly discharging capacitors into these meters?   I hooked my meter to the output of a MOT and it stopped working, can you tell me what went wrong and how to fix it?  Can you show me how to protect my meter against these sort of things,  I'm educated and know what I am doing?   :-DD  Never mind, it's a bad idea!   :-DD   Still though, just showing the testing like Fluke has done for some of their internal tests would be very educational.   

Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 17, 2018, 03:22:21 pm
Joe, not that I'm trying to batter with questions here, but do you have criteria for which contact to choose? My hunch on the numbers is that distance from the vertex may affect settling times (say, measuring during a detent sliding contacts into a rest position). I'm confident you're measuring during actuator pauses, but does your sample delay increase if a meters sample point is farther out on the radius?

Also, what have you noticed in general about meters with double contact points (ie: not just resistance, but track wear depth and fragility?)

** Edit: eg: meters similar to this one..
(https://s18.postimg.org/w8s3bm22h/Fluke_189_double_contact_points.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 17, 2018, 05:45:21 pm
Joe, not that I'm trying to batter with questions here, but do you have criteria for which contact to choose? My hunch on the numbers is that distance from the vertex may affect settling times (say, measuring during a detent sliding contacts into a rest position). I'm confident you're measuring during actuator pauses, but does your sample delay increase if a meters sample point is farther out on the radius?

Also, what have you noticed in general about meters with double contact points (ie: not just resistance, but track wear depth and fragility?)

** Edit: eg: meters similar to this one..

Let's start with your question about the multicontact wiper.  What meter was it that I looked at that had this design?  How did it perform?   I think if you answer that first question you may find your answer.    That said, if you were interested in large studies, I would look towards the automotive industry and the US military.   I would recommend looking at variable resistors as well to learn about it.   I certainly would not gleam anything about the contact designs or lubrication from the little testing I have done.  I do believe we are seeing some trends in the quality of the switch based on brand but even that is too early to say.

About the settling time.  You are correct in that I do not attempt to read the resistance while the switch is in motion.  The motor does have a settle time and it detects when it is done moving.  I also wait a fixed time and then the meter itself has to settle out as well.  But when you only rotate every three seconds or so, there is plenty of time to let things settle.  There would never be a reason to try and speed things up.  It's not a sprint, its a several day marathon.  Again, running them too fast, you may find the plastic will start to build heat.  It's interesting to see how fast and how many cycles Brymen runs compared with my swag. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 17, 2018, 07:44:52 pm
By swag, you mean the Metrahit produkt? :-DD  So you select the set of traces with fewest via's then?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 17, 2018, 11:58:27 pm
Swag in this context meaning a stab in the dark or wild guess.   The Gossen is bling. 

Are you asking how I determine which set of contacts to use?  The first thing I want  is to be able to read it when the switch is at one side or the other.   Some rotate 360 so then it does not matter so much.   I try to look for contacts that I can tack into without disturbing anything or adding heat to the switch.  I also like to find contacts with a lot of surface area.  Basically, I don't want a short pad in case the wiper cuts all the way through it.   In the end, when that has happened, everything had major damage so I doubt it really matters too much.   

We also have the visual data to go along with it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 20, 2018, 07:34:37 pm
The Brymen BM839.   More info on this meter may be found at:
http://www.brymen.com/PD02BM830_839.html (http://www.brymen.com/PD02BM830_839.html)

https://youtu.be/bNzd5wo6FWU (https://youtu.be/bNzd5wo6FWU)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 20, 2018, 08:13:07 pm
Yikes! Now that's a porn shot! You must have taken all night to render too (not to mention shoot it). Nobody does it like Joe - period.
(https://s18.postimg.org/se9dh0mll/Joe_stacking_the_deck.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on January 20, 2018, 09:07:29 pm
Price of BM839 in Welectron (Germany) is 150€ (no Vat)... It is actually more expensive than BM867, that is 133€ (no Vat)... I don't see it as a better than BM867... Funny...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on January 20, 2018, 11:23:35 pm
Does this mean we get to add another 100,000 cycles to the Brymen and Fluke 17B+?

Duel to the death!

PS: Did the Fluke's switch wipers go under the Microscope? It's not in the original video.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 20, 2018, 11:36:01 pm
No need. Just have blind faith, Fluke's contacts are certified to hold up during nuclear shock waves!  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on January 20, 2018, 11:39:36 pm
No need. Just have blind faith, Fluke's contacts are certified to hold up during nuclear shock waves!  :-DD

The Fluke will win easily if the contact resistance graphs are any indication.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 21, 2018, 01:05:16 am
If there is a contest, the Keysight meter would win some sort of award for their design.   The mark of true quality right here.   
Title: Re: Handheld meter electrical robustness testing.
Post by: kalel on January 21, 2018, 10:46:53 am
The UT210E's added bandwidth was enough to get the video flagged for copyright infringement.  The sound quality has improved beyond what the UT90A was capable of.   :-DD   
If they start to place adds on it, I will most likely remove it.

Can you use some music that doesn't trigger those things? There is "open" music (public domain or creative commons). That is, if you're interested in making such tests in the future, otherwise it really doesn't matter.
Title: Re: Handheld meter electrical robustness testing.
Post by: Hydrawerk on January 21, 2018, 05:48:52 pm
I am happy that Brymen introduced a DMM powered by AA cells and with easy removable fuses. I noticed that the internal PCB is a bit unpopulated. Are there new improved meters coming? https://www.youtube.com/watch?v=bNzd5wo6FWU (https://www.youtube.com/watch?v=bNzd5wo6FWU)
On the other hand, the Brymen BM839 is not much feature wise.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on January 21, 2018, 05:51:01 pm
Can you use some music that doesn't trigger those things? There is "open" music (public domain or creative commons). That is, if you're interested in making such tests in the future, otherwise it really doesn't matter.

There's actually some "Youtube friendly" music supplied by Google that you use. I assume there's no way that can be flagged.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 21, 2018, 06:39:57 pm
If he has to re-post this 90min video again, he'll have to re-shoot the segment and render. What a pain! That was fair use of fast fingers!
(for keyboards, try this for fast http://bit.ly/2F2Hm3E (http://bit.ly/2F2Hm3E) )  8)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 21, 2018, 11:29:21 pm
Wow.. Nothing can top that. I bet YT would never be able to identify that second guy - frigging awesome!
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on January 22, 2018, 05:37:49 am
I like the big bands and am a bit of a Buddy Rich fan myself.  Here with Gene Krupa and Sammy Davis Jr. 
https://www.youtube.com/watch?v=NKtoskzi9Pc (https://www.youtube.com/watch?v=NKtoskzi9Pc)

Excellent! Amazing the good stuff you find on this forum. ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 23, 2018, 05:23:14 am
Having a wimpy meter may be alright for some people but not for me.   While testing has shown that my favorite meter can take a pretty big hit before it is damaged,  it just does not seem right that the cheep little ZT102 / AN8002 can out perform it. 

If you like wimpy meters, this next video is not for you but if you want to see my favorite meter step up it's game, stay tuned.   It's 14KV or BUST!!
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 23, 2018, 12:51:48 pm
Having a wimpy meter may be alright for some people but not for me.   While testing has shown that my favorite meter can take a pretty big hit before it is damaged,  it just does not seem right that the cheep little ZT102 / AN8002 can out perform it. 

If you like wimpy meters, this next video is not for you but if you want to see my favorite meter step up it's game, stay tuned.   It's 14KV or BUST!!
Let me guess.. You could call it the yellow wonder. A totally potted Harbor Freight blue-light special?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 23, 2018, 12:57:36 pm
It's had it's rotary switch cycled 50,000 times,  it's swam with the fishes and it has been exposed to transient levels that damaged it's input.   Can it survive a 14,000 volt transient with a $1.00 budget and no PCB changes?   Watch and find out. 

https://youtu.be/u9P4N5HPwf4
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on January 24, 2018, 02:57:30 am
It's had it's rotary switch cycled 50,000 times,  it's swam with the fishes and it has been exposed to transient levels that damaged it's input.   Can it survive a 14,000 volt transient with a $1.00 budget and no PCB changes?   Watch and find out. 

https://youtu.be/u9P4N5HPwf4

$1 in parts and $10 million in engineering later ... :-DD


Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 24, 2018, 02:33:17 pm
$1 in parts and $10 million in engineering later ... :-DD
:-DD  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: Scottjd on January 24, 2018, 05:26:03 pm
$1 in parts and $10 million in engineering later ... :-DD
Just finished watching the video.  :popcorn:
Well those transistors are not cheap, maybe a little more then $1 for parts.
But the time spent in testing and engineering, the custom build generators, home made high voltage probe on the oscilloscope.
Hats off to you sir,  :clap: Truly a great accomplishment, and great work.

So what’s the lesson learned from this. Do they need to put better parts that are equal to or of higher value in front of the PTC’s and what they are rated for? So if the PTC is rated for X then why put transistors that can only handle C in front of them?
This kind of sounds like common sense now when I ask it like that. I’m not trying to over simplify it, but it might sound like that and I couldn’t figure another way to ask the questions.

That’s one impressive meter for sure, especially with the “Joe Touch” mod. Maybe you should start award levels now? The highest awarded would be to meet or exceed your modified meter testing results, but being stock with no mods or updated parts.

Questions, maybe a dumb one but I’ll ask it anyway.
First, how much can your high voltage scope probe handle, will you need to make a new one if meters start to handle more power then 15KV?

I recently tore down a dead USB QC capable power supply for a Lanova Yoga laptop and noticed spark gaps between the common mode choke on the AC input side. So I was wondering, what if they had still used the cheaper transitors but added some spark gaps on the PCB before them with proper insulation? Would or could this result in the same affect as the higher end transitors? Or am I thinking crazy thoughts?

Side Note: Great reference about USB switch mode power supplies. I found this page full of good information. Since I never repaired a USB power supply (or any power supply) I went searching and found this page to be full of good info:http://lygte-info.dk/info/SMPS%20workings%20UK.html (http://lygte-info.dk/info/SMPS%20workings%20UK.html)

Thanks again for all the hard work, great testing and time spent editing and doing these videos.
Maybe now it’s time to take a break.  :phew:
Scott
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on January 24, 2018, 05:39:20 pm
So what’s the lesson learned from this. Do they need to put better parts...

The CAT rating for this meter goes up to 8000 volt transients, the parts currently in the meter meet those requirements (presumably - I know Joe's tests aren't the same as a real CAT rating test) so there's no requirement to replace them.

Joe's just showing off by making it into a 12kV+ meter.  :popcorn:

(and learning...)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 24, 2018, 05:44:39 pm
Joe's just showing off by making it into a 12kV+ meter.  :popcorn:

(and learning...)
Always learning.... 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 24, 2018, 06:15:36 pm
$1 in parts and $10 million in engineering later ... :-DD
Just finished watching the video.  :popcorn:
Well those transistors are not cheap, maybe a little more then $1 for parts.

So what’s the lesson learned from this. Do they need to put better parts that are equal to or of higher value in front of the PTC’s and what they are rated for? So if the PTC is rated for X then why put transistors that can only handle C in front of them?

That’s one impressive meter for sure, especially with the “Joe Touch” mod. Maybe you should start award levels now? The highest awarded would be to meet or exceed your modified meter testing results, but being stock with no mods or updated parts.

Questions, maybe a dumb one but I’ll ask it anyway.
First, how much can your high voltage scope probe handle, will you need to make a new one if meters start to handle more power then 15KV?

....
Thanks again for all the hard work, great testing and time spent editing and doing these videos.
Maybe now it’s time to take a break.  :phew:

As stated, my cost was under $1 w/ tax.

PTCs are before the transistors, not after.   Meters will be different.  If we are talking about this one specifically, you have the PTC in series with the two resistors.  Again, the PTC is not going to do much of anything beyond act as a resistor in the HV transient tests.  If in resistance mode for example, we have the drop of the clamp.  Basically nothing.  Then you need to consider the transient.  It's not a matter of just looking at the voltages present.  I know I get a fair number of MOT and DC comments from people but the reality is this is not at all what we are looking at. 

I doubt when a company like Brymen designs a meter they are thinking we need to meet the JQS transient tests and survive.  They will design around what ever standards they want to meet and use what ever internal best practices they have come up with.  From what I have seen, companies all follow the same basic concepts.  It's all fairly well understood.  I can't understand why a brand new meter like the 121GW for example would not be very robust.  If you have watched some of my videos, it's not a lot of added cost. 

I have a playlist for the home made HV probes, linked below.  I called it 40KV but I've ran tests far above that to make sure it was not going to be a problem.  You mention power rather than voltage.  I assume a mistake in terms but If you watch the videos, I do talk about the life of the parts based on how hard you run them.   It may be shorter than you think.   

Break??  lol.  I make the videos for the fun of it.  I don't ask for handouts and rarely accept meters to run.  If I need a break, that means I have lost interest and it's no longer fun.  When that time comes, I will just stop making them.  Growing the channel and making money was never part of it.   

https://www.youtube.com/playlist?list=PLZSS2ajxhiQCAQ6gIp6s-WoKiIEb1gHPD (https://www.youtube.com/playlist?list=PLZSS2ajxhiQCAQ6gIp6s-WoKiIEb1gHPD)
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on January 27, 2018, 10:18:44 pm
Nice one Joe.
Thanks for the time and effort.
3DB  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 03, 2018, 12:29:53 pm
Oh, no! You know now that you are mandated by TEA (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/) law to amend your warning statements, right?  "Warning: multimeters AND probes were harmed in the making of this video. TEA viewer discretion is advised."

I remember very well the HV probe discussion as I was interested in making one as well and even got the parts, etc. One thing lead to another and i still didn't find the time to finish this project...  :palm:

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 04, 2018, 12:15:37 am
Oh, no! You know now that you are mandated by TEA (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/) law to amend your warning statements, right?  "Warning: multimeters AND probes were harmed in the making of this video. TEA viewer discretion is advised."

I remember very well the HV probe discussion as I was interested in making one as well and even got the parts, etc. One thing lead to another and i still didn't find the time to finish this project...  :palm:

As a hobbyist, I enjoy designing and building projects like this and have respect for anyone who attempts them.   Making a DC probe is one thing but add over 10KV to the mix and top it off with AC responses in the MHz, it turns into several hours of play time. 

We are back in business.
https://youtu.be/kWOe803atvg (https://youtu.be/kWOe803atvg)

 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 16, 2018, 12:19:00 am
With the HV probe repaired and checked out, it's time to look at another meter.    I offered to let people pick the meter at 2000 subscribers and everyone wanted to see the 121GW.  Sadly the meter is still not available.   But I can offer to run another Fluke 87V which was peoples third pick after the Gossen.

We know the 87V I looked at could not come close to the performance of any of the the Chinese made Flukes I have looked.   I was asked about the revision of the meter I last ran and it was not the most recent.    What  I am thinking is to buy a brand new one, directly from Fluke and repeat all of the transient tests.  Maybe run a temperature sweep on it. 

I am not so sure where the 87V is made anymore.  The US laws on what it means to be made in the USA are pretty relaxed.  I would have to see the assembly line, here in the USA with this meter being made to know what it means anymore.    Danaher always seems to be listed in the top companies for unrepatriated profits.  It is what it is.   If China is doing the majority of the work now, it may prove to be a more robust meter.    Even that its a later design that the last one I looked at, maybe they improved it. 

The Fluke 17B+ is still the best performer from my life cycle testing.  I have been wanting to run another Fluke and it seems only fitting that the king pin of Fluke, the meter that all others are ranked against, gets a shot at that as well.   Not a 50,000 half stroke test , but the full rotation for 50K cycles that all of the other meters have been tested to.     

It may seem I have an axe to grind with Fluke.  I don't.  I am more than willing to give a brand new one a fair shake and let the data once again stand on it's own.   

So stay tuned.... 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on February 16, 2018, 01:02:00 am
Looking forward to it, Joe. I don't think you have any axes to grind. Even if you did, it ends up generating interesting videos. So, onward with the tests.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 16, 2018, 01:50:25 am
Joe, I think the 87V was one of the most controversial and surprising results you got. Definitely worth testing it again. IMHO the 121GW should be given a year or so given it is still being polished.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 16, 2018, 02:21:34 am
I am pretty sure that the most down voted video I made was the first run of the UT139.  Just looked, oh yea, 43 up, 56 down.  Of course, I repeated that test and the meter failed pretty much where we would have expected but the video ended up with 155 up and 10 down votes.   I guess the UNI-T fans felt I did not give their meter the respect it deserved.   :-DD 

So far, any time I have repeated a test, we get the expected results.  It shows that some of these companies have some level of quality process controls.  In the case of the Fluke however, we know they changed the PCB so it's a little different.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 16, 2018, 02:20:34 pm
You've been so long on Youtube and still believe in measuring things by up/down ratings? I have a bridge to sell to you... :-DD

In a more serious tone, I suspect you are right. Remember my comment about Uni-T snowflake owners?
https://www.eevblog.com/forum/testgear/worst-handheld-multi-meter-still-available/msg1337635/#msg1337635 (https://www.eevblog.com/forum/testgear/worst-handheld-multi-meter-still-available/msg1337635/#msg1337635)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 16, 2018, 06:00:54 pm
I've been on YT long enough to know it's not just the UNI-T owners. 

I was reading through this old thread about the 87V and change in quality  and may compare an older 87V with the new one.  Maybe there are other differences beyond what was mentioned in the thread. 
https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/200/ (https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/200/)

Read through the FTC documents to see what was involved.  It may help explain some of the changes on how they are marked. 
https://www.ftc.gov/tips-advice/business-center/guidance/complying-made-usa-standard (https://www.ftc.gov/tips-advice/business-center/guidance/complying-made-usa-standard)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 16, 2018, 08:26:31 pm
I was reading through this old thread about the 87V and change in quality  and may compare an older 87V with the new one.  Maybe there are other differences beyond what was mentioned in the thread. 
https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/200/ (https://www.eevblog.com/forum/testgear/fluke-87v-(2017)-lacking-quality-control/200/)
Yes, I remember this thread - a good read after you skim through the trollery. There was some indications of production/material differences but IIRC nothing really conclusive towards declining quality.

Read through the FTC documents to see what was involved.  It may help explain some of the changes on how they are marked. 
https://www.ftc.gov/tips-advice/business-center/guidance/complying-made-usa-standard (https://www.ftc.gov/tips-advice/business-center/guidance/complying-made-usa-standard)
Thanks for sharing. The FTC does a similar thing as it used to be done in Brazil: assembly must be done in country to be considered "Made in <country>". The issue is that it does not necessarily guarantee the quality of the supply chain, but I personally am pretty sure Fluke would never risk their reputation by skimping on that. 

(off-topic) Did you see this?

https://youtu.be/QSmiMlWEpy0 (https://youtu.be/QSmiMlWEpy0)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 16, 2018, 11:33:51 pm
I've been commenting about his 50,000 cycle test in the sticky 121GW discussion tread.  I understand the fixture is working well and they plan to add a resistance measurement to it.   Currently they define a cycle to be what Brymen and I consider a half cycle.   It would be great if they would read the switch resistance for each cycle and run the same number of cycles.   We could then compare the data they collect with the other meters I have looked at.    I don't think the small difference in the speed his is cycling would make much, if any difference. 

I like the Panavise for a few reasons.  I don't plan on testing very many meters and this was zero investment, plus it gets used for other things.  It's a very flexible setup for running various meters.  I can see the meter while it is cycling and note any problems.   

I like using a PC for automating test.  It's easy to get something setup and collecting and post processing the data is a snap.

Looking forward to seeing how their testing comes out. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 17, 2018, 11:11:00 pm
Center stage, a brand new Fluke 87V hot off the production line.  No bias and no excuses.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on February 18, 2018, 12:26:23 am
Woohoo! New toys. :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 19, 2018, 08:39:59 am
The Fluke 87V Part I.

https://youtu.be/DA77DYGE6IM
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 19, 2018, 08:56:23 am
But I can offer to run another Fluke 87V which was peoples third pick after the Gossen.

We know the 87V I looked at could not come close to the performance of any of the the Chinese made Flukes I have looked.   I was asked about the revision of the meter I last ran and it was not the most recent.

Revision, shmevision. If it had a "V" in the name then it's had plenty of time to be revised by Fluke. Anything else is just people looking for excuses.

What  I am thinking is to buy a brand new one, directly from Fluke and repeat all of the transient tests.

Has anybody at Fluke shown any interest in your work?

Send them the latest video of the Brymen - the one where you mention that Brymen send you a box of free meters.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 19, 2018, 09:10:59 am
Intro.   

https://youtu.be/3dxEmi4FGT0?t=817

When the wire touching the edge of the beaker glowed red hot I was waiting for the beaker to crack and water to flood across a big table full of electricity...

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 19, 2018, 09:55:53 am
I'm sure the rubber shoe on the Fluke 87 will soon "age" to match the color of the kickstand.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 19, 2018, 12:52:18 pm
Has anybody at Fluke shown any interest in your work?

Send them the latest video of the Brymen - the one where you mention that Brymen send you a box of free meters.  :popcorn:

No they have never expressed any interest. 

I'm sure the rubber shoe on the Fluke 87 will soon "age" to match the color of the kickstand.

I highly doubt it.  I watched the video and it's difficult to see the color difference so I have attached a few pictures of the new and older meter.  I tried to get a closeup of the surface finish of the boot as well.  With them being so interested in the Fluke colors, I would never expect to see this poor of quality on what I understand is their number one selling meter, the one all meters are compared against, not to mention about $400. 

Then again, I am more curious to see why this switch is grinding.   I am interested in seeing the effects of the life cycle test.
Title: Re: Handheld meter electrical robustness testing.
Post by: BravoV on February 19, 2018, 01:23:00 pm
Regarding the Fluke's "yellow", just took this recently, its on Sun's light and with manual white balance compensated.

They're just different, at least to my eyes when saw them physically, and also at my monitor at this photo below.

(https://www.eevblog.com/forum/chat/show-your-multimeter!/?action=dlattach;attach=394899;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 19, 2018, 05:11:43 pm
"...I'll use the Brymen here to try to troubleshoot the 87V..." Ouch!

I guess the 87V falls into the category of "electrically snowflaked meter"TM.

The mechanical properties (color and silk, mechanical switch) are most probably due to the growing pains of adjusting to a new supplier and/or manufacturing house. 

Regarding Fluke apparently not paying attention to your tests, I have a hunch they are. Just not admitting it.

The change in certifications seems to have removed the listing at UL - I know that a listed product requires long term commitments regarding quality inspections and other details, which is a continuous stream of negative revenue.

This and the cheapening of the product may indicate many things, ranging from the influence of the bean counters at Danaher to the market analysts that are planning a sunset of this product. This theory may be solid if other brand new Fluke models still have listed markings on them, which isolates this model as the "ugly duck". On the other hand, setting up a new manufacturing plant for something that is being phased out looks like a bad move. Without sales figures over time, it is impossible to know for sure.

At any rate, I suspect the market for 20000 count industrial meters may be shrinking - I wouldn't be surprised if electricians are choosing simpler and cheaper meters (even from Fluke), as they rarely require the resolution and only a few of the additional features of an 87V. As for the electronics market, the competition is quite fierce nowadays especially given the liability in this market is severely reduced.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on February 19, 2018, 08:42:56 pm
I also think 87V is a meter with identity crisis... Too fancy to sit on the bottom of tool case in oil and dirt and a hammer on top, and not really best electronics meter out there.. I also think 189 was much better meter for electronics.. For electrician, likes of BM257, and simpler Flukes are much cheaper and excellent choice..

I noticed that new one is missing one very important mark: TUV GS certification mark.  It shows TUV SUD, meaning that TUV did testing (probably they did CE certification for them). But no GS mark.
TUV GS mark signifies that product is safety tested to higher standards than basic minimums for CE.....

I'm really sad to see Fluke is slipping. I have been using it for many years, privately and professionally, from model 8020B, 8060A, 73 III, 87 in few incarnations, 189 and Scopemeter 97...  They were good quality and innovative.. Not any more.. Now they are simply decent, for too much money...

And 87 V on this test is not even decent... It's in a UNI-T class... and in EU it is cca 500€..

For that money I could get BM869S and BM525 with logging and PC cable instead ...
Oh wait, I DID ....   :-)

As always, nice work Joe, looking forward to the rest of the test.

Regards,

Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2018, 02:28:47 am
Found the problem with why the 87V would display an open above 470 degrees C and have made a change to my circuit to support the 87V's unique feature.  Personally, I think they could have done a better job integrating the high res mode to make it more transparent.   

https://youtu.be/iEo1W4tWjEM
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 20, 2018, 07:05:42 pm
Quite interesting is how the 87V deals with the "hi-res" mode - does that stay enabled after the meter is power cycled? If not, that would greatly detract from a usability standpoint.

Just :horse:, even the UT61E comes with 0.01\$\Omega\$ resolution by default.
Title: Re: Handheld meter electrical robustness testing.
Post by: Paul Moir on February 20, 2018, 10:40:10 pm
Regarding "Made In" vs "Assembled In", this can be due to evolving regulatory regimes or if they haven't evolved yet, minimizing regulatory risk.  This has already happened to other industries.  For example, what do you mean by "Made in America?"  Certainly the silicon wasn't fabbed there, and if you're buying parts how can you be sure your suppliers won't change part of it's manufacture to overseas?
Compounding the issue is perhaps you want to sell the same product in several markets all with their aligned but have separate regulatory regimes.  Maybe one of them tightens up the "Made In" meaning.  Best to avoid the whole situation and say what's true, that you at least assembled it in the USA.

The change in certifications seems to have removed the listing at UL - I know that a listed product requires long term commitments regarding quality inspections and other details, which is a continuous stream of negative revenue.

The UL-CSA mark is equivalent to a UL mark.  There's no need to have both any more as both agencies can cross certify by agreement.  Fluke moved to CSA many years ago for no doubt good reasons which have nothing to do with "long term commitments regarding quality." 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 21, 2018, 01:30:03 am
Back about 10 posts, I linked the FTC document describing the requirements for the various markings.

Someone posted about how I had zero'ed out the 87V causing the large error in the reading.  Pictures showing my old HP in 4-wire, not zero'ed with leads shorted and leads attached to the common leads of the 4-wire 1% 0.1 ohm resistor. 

The 87V manual only seems to show the 0.1ohm res, so I would assume +/-0.2% FS + 2*0.1 ohms, rather then 2*0.01 ohms.  Not the best manual for a meter so mature and with such a high price tag.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 21, 2018, 01:47:15 am
Quite interesting is how the 87V deals with the "hi-res" mode - does that stay enabled after the meter is power cycled? If not, that would greatly detract from a usability standpoint.

Just :horse:, even the UT61E comes with 0.01\$\Omega\$ resolution by default.

No, the old Fluke meter has no sticky settings like Brymens.  IMO, the meter should have an auto mode for that high res.  I doubt many electricians have a need for that feature.  I can't see too many hobbyist wanting it but then again, if you were driven by marketing, maybe. 

I think the only two meters I looked at that can resolve 1mohm are the Gossen and TPI.  I can't really count the UEI meter.  If the Gossen did not have so many problems, it would be a very nice meter.  I wonder if they ever did anything with it or decided it was not worth going after.     
Title: Re: Handheld meter electrical robustness testing.
Post by: Paul Moir on February 21, 2018, 01:55:23 am
Back about 10 posts, I linked the FTC document describing the requirements for the various markings.
Yes, but your missing the point about multiple regulation regimes and regulatory risk.  Regulations change.  Multiply that by how many regulatory regimes (eg, countries) this meter is sold in.  Sometimes when they change regulations they do it too fast to clear out all the stock before they come into effect.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 21, 2018, 02:15:32 am
Back about 10 posts, I linked the FTC document describing the requirements for the various markings.
Yes, but your missing the point about multiple regulation regimes and regulatory risk.  Regulations change.  Multiply that by how many regulatory regimes (eg, countries) this meter is sold in.  Sometimes when they change regulations they do it too fast to clear out all the stock before they come into effect.
I'm missing a point? 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 21, 2018, 02:32:24 am
The change in certifications seems to have removed the listing at UL - I know that a listed product requires long term commitments regarding quality inspections and other details, which is a continuous stream of negative revenue.

The UL-CSA mark is equivalent to a UL mark.  There's no need to have both any more as both agencies can cross certify by agreement.  Fluke moved to CSA many years ago for no doubt good reasons which have nothing to do with "long term commitments regarding quality."
I am not sure what are the commitments of the UL or UL-CSA marks, but I was referring the UL listing number which requires annual "audits" on the manufacturing facility and design changes and not your typical "fire-and-forget" certification testing of your pre-release / initial production products. This is a long term committment that prevents the product from having its quality erode over time as Extech, for example.

Quite interesting is how the 87V deals with the "hi-res" mode - does that stay enabled after the meter is power cycled? If not, that would greatly detract from a usability standpoint.

Just :horse:, even the UT61E comes with 0.01\$\Omega\$ resolution by default.

No, the old Fluke meter has no sticky settings like Brymens.  IMO, the meter should have an auto mode for that high res.  I doubt many electricians have a need for that feature.  I can't see too many hobbyist wanting it but then again, if you were driven by marketing, maybe. 

I think the only two meters I looked at that can resolve 1mohm are the Gossen and TPI.  I can't really count the UEI meter.  If the Gossen did not have so many problems, it would be a very nice meter.  I wonder if they ever did anything with it or decided it was not worth going after.     
Too bad. My previously owned 179 did not have sticky settings as well and it was quite expensive, although it seemed to be tailored to a different market.

1m\$\Omega\$ is quite a resolution - on par with a number of 5-1/2 digit meters.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 23, 2018, 01:26:57 pm
I wonder if they are looking at it in the ACV setting and measuring the leakage of the cap.   I could check my Brymen in this same way and see if I can get the same accuracy and resolution as the 87V in the volts mode.  I think the Brymen is also AC coupled in this mode so it should perform well.    I could try and measure it but  then again, normally you look at AC with the AC settings and that cap is not going to be the 10 zigga ohms.   

Anyone else care to chime in on this comment as right now, I am a bit lost as to what the OP is describing.   
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on February 23, 2018, 01:35:23 pm
High impedance mV ranges will often clamp input below 1V (Through a resistor/PTC), i.e. a normal ohm meter will not always show the correct impedance. In all my reviews I use a source meter where I can control the voltage when measuring ohms.
They will often switch a 10Mohm resistor in for AC mV
I do not have the 87V and cannot check that meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on February 23, 2018, 01:59:01 pm
It it probably leakage of input protection circuits plus capacitor leakage (probably not major contributor) when AC coupled..
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 23, 2018, 05:04:48 pm
If that is true, what is unique? Heck, even the UT61E claims >3G\$\Omega\$ input impedance in mV ranges... My Racal Dana measures the UT61E as having 52M\$\Omega\$, but I suspect this may be wrong as clamping may be influencing it (it puts out a couple of V)
Title: Re: Handheld meter electrical robustness testing.
Post by: WhichEnt2 on February 24, 2018, 09:02:04 am
If that is true, what is unique? Heck, even the UT61E claims >3G\$\Omega\$ input impedance in mV ranges... My Racal Dana measures the UT61E as having 52M\$\Omega\$, but I suspect this may be wrong as clamping may be influencing it (it puts out a couple of V)

Sure it is clamped.
UT71E and Fluke 87V (hi Z option on) mV input resistance reads OL while being measured by Agilent U1252A
But if that resistance is measured by F87V it reads about 4.7 MOhm on UT71E and 16 MOhm on U1252A.
Fluke 87V on 11 MOhm load (DC V input resistance) feed about 2.7 V into leads.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 04:48:12 pm
Someone wrote me about the Hi-Z mode.  Strange the spec sheet does not reflect the input impedance when this mode is selected.   I suspect this is what the OP was referring to but I am not sure where they are coming up with the 4G.   

With as popular as the meter is, and this Hi-Z mode being a selling feature, strange there are not published specs or at least posts where people have measured it. 

https://www.eevblog.com/forum/chat/fluke-87v-high-z-mode-input-impedance-value/ (https://www.eevblog.com/forum/chat/fluke-87v-high-z-mode-input-impedance-value/)
https://www.eevblog.com/forum/testgear/multimeter-input-impedance-riddle/ (https://www.eevblog.com/forum/testgear/multimeter-input-impedance-riddle/)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 06:13:37 pm
I tried using my vintage electrometer to measure the input impedance directly.  This uses a constant current source and can output around 30V.  With the standard DCmV selected, I read 10Meg.  No surprise.   Selecting Hi-Z, the electrometer measure 22.4Gohm.  However,  this means it is putting 2.24V across the meter.   

Using a constant voltage source at 490.03mV (within what the 87V can measure in the DCmV range) and using the electrometer to measure the current, I get about 23pA.  So roughly 21.3Gohm. 

Of course if you really needed higher input impedance for mV measurements, even this old electrometer is 50Tohms and has a resolution of 10uV.  Then again, it doesn't fit in the palm of your hand.

If anyone else has the 87V,  I am interested in hearing how this new one compares with others.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 08:04:59 pm
If that is true, what is unique? Heck, even the UT61E claims >3G\$\Omega\$ input impedance in mV ranges... My Racal Dana measures the UT61E as having 52M\$\Omega\$, but I suspect this may be wrong as clamping may be influencing it (it puts out a couple of V)

My UT61E has had a LOT of mods and I doubt very much it would be the same if it were still a virgin meter.    In the DVmV range, I used a 198.29mV source to keep it in range.  I measure 28.5pA with the electrometer.   So very close to 7Gohm.  At least you know I cleaned it fairly well and their claim of being greater than 3Gohm seems correct. 

For fun, I tried to measure the pre-production 121GW that I damaged a few times, repaired and modified.   Measuring it directly with the electrometer, 0.200Mohms.    I then tried it with a 183.40mV (well within the range of the meter) and measured 918nA or 199.782Kohms.    Again, I doubt the people who have the released meter (on Amp Hour these were referred to as Beta units) would get the same results but it would be interesting to compare. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 08:14:53 pm
For the ANENG fans or in my case the KASUNTEST, looking at the ZT102 that I modified to survive the 14KV transient, in the DCmV with 198.3mV applied, the electrometer measures 14.7pA or 13.49Gohm.   Again, that meter has some major mods done to it and I would expect a virgin unit would be different.  Does show that the dope I used on some of these meters is not causing much of an error.   
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on February 24, 2018, 08:24:51 pm
Many meters are high impedance in the DC mV range. How high that is I will not say anything about, my normal setup is way to noise to measure gigaohms at sub volt ranges, I will only say it is in the gigaohm range.
I.e. either the meter is 10Mohm or it is gigaohms, very few meters are lower impedance in the mV range, but overvoltage will usual clamp with a fairly low impedance (kohm).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 08:43:29 pm
The TPI (Summit) 194II lime green meter with 490.50mV applied, the electrometer measure 2.22nA or 220Mohm.  Now this meter is damaged and I never was able to find a new front end IC to repair it.  It lost some of the multiplexer.  It is still able to accurately measure the DCmV but the low levels may not be normal.   

I am not sure why the 121GW was so low.  It could very well be because of my mods.  Then again, I damaged that meter a few times as well.  Someone else really needs to check it.
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on February 24, 2018, 08:51:01 pm
I am not sure why the 121GW was so low.  It could very well be because of my mods.  Then again, I damaged that meter a few times as well.  Someone else really needs to check it.

I suppose you are going to check it again when you get the production version. I am also going to check it and do my usual multimeter review of it.
I suppose the timing estimate now is late March.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 09:10:01 pm
I mentioned a use an Extech meter for work.  Some time back I bought a CEM DT9939 which is identical to my EX540. This is a 40,000 count tri-display meter with all the basics including AC+DC.  The one I use is coming up on six years old and has had seen a fair amount of abuse.   Ruby Electronics was selling these for $120 which was a great deal.    Again, I damaged the meter during my tests and only replaced the parts.  So no modifications for a change. 

The CEM in DCmV with 198.20mV applied, the electrometer measures 1.5pA or 132Gohm.   I then increased the input to 490mV which is outside what the meter can measure.  This yields 4.1pA or 119.5Gohms.   A fair amount higher than I saw with the Fluke 87V but again no where near the 50Tohms of the electrometer. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 24, 2018, 09:20:53 pm
I am not sure why the 121GW was so low.  It could very well be because of my mods.  Then again, I damaged that meter a few times as well.  Someone else really needs to check it.

I suppose you are going to check it again when you get the production version. I am also going to check it and do my usual multimeter review of it.
I suppose the timing estimate now is late March.

There is one for sale in on this site and the owner has offered to ship to the US.  Maybe other places as well.  I thought about it but with the time it takes me to run the tests, the last thing I want to hear is how what I was showing was a Beta meter.  I would rather hold off until they get everything sorted out and are happy with their testing.   I doubt this particular metric would change much from the Beta units.  It's non-destructive so no problem for people who own them to make the measurement and compare results. 

The pictures I posted of the metallic dust between the switch contacts was discovered when I first damaged the meter.  I had cleaned the circuit board a few times after taking those pictures.   But again, the mods are a strong possibility.   Sub 200K, easy enough to check.. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 25, 2018, 01:37:25 am
Many of the meters I have including the Brymen BM869s, Fluke 196, Gossen M248B, UNI-T UT181A are 10 or 11Meg.  Even the free harbor freight meter was close to 10M.   A few meters were 5M.   I found one that was lower than the pre-production 121GW.   The YX-360TR.  Again, highly modified after being damaged.  This meter measures close to 2Kohms in the DC 100mV range. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 25, 2018, 02:26:16 am
Many of the meters I have including the Brymen BM869s, Fluke 196, Gossen M248B, UNI-T UT181A are 10 or 11Meg.  Even the free harbor freight meter was close to 10M.   A few meters were 5M.   I found one that was lower than the pre-production 121GW.   The YX-360TR.  Again, highly modified after being damaged.  This meter measures close to 2Kohms in the DC 100mV range.
That is a novelty. All M830B clones I have seen have 1M\$\Omega\$ of input impedance in all DC ranges. They even mention this in their manuals.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 25, 2018, 03:19:43 am
Many of the meters I have including the Brymen BM869s, Fluke 196, Gossen M248B, UNI-T UT181A are 10 or 11Meg.  Even the free harbor freight meter was close to 10M.   A few meters were 5M.   I found one that was lower than the pre-production 121GW.   The YX-360TR.  Again, highly modified after being damaged.  This meter measures close to 2Kohms in the DC 100mV range.
That is a novelty. All M830B clones I have seen have 1M\$\Omega\$ of input impedance in all DC ranges. They even mention this in their manuals.

This is that yellow one that was given to me.   I wonder if I read it wrong.  ...... Yep.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 27, 2018, 12:37:55 am
It seems the released 121GW meters are 10Meg in the mV range.   Looking at the schematic and pictures of the new boards, I suspect that the low resistance I measured is finding it's way through U14 and R91 which are no longer populated.  R91 just happened to be a 200Kohm so this is a strong possibility.   

Sure enough, put it into temperature mode, 10Meg.   It would be interesting to know why they wanted such a low input impedance and then decided to go away from it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 04, 2018, 12:44:24 am
Do a search some time of the 87V to see what problems people have had with this pinnacle of meters and you may be amazed.   I wanted to see if anyone else had performed some sort of AC line test, intentional or not.  I think I have my answer:

https://www.eevblog.com/forum/testgear/fixing-a-fluke-87v/ (https://www.eevblog.com/forum/testgear/fixing-a-fluke-87v/)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 04, 2018, 12:46:35 am
Do a search some time of the 87V to see what problems people have had with this pinnacle of meters and you may be amazed.   I wanted to see if anyone else had performed some sort of AC line test, intentional or not.  I think I have my answer:

https://www.eevblog.com/forum/testgear/fixing-a-fluke-87v/ (https://www.eevblog.com/forum/testgear/fixing-a-fluke-87v/)

Jeez. My 13 Euro LIDL multimeter survived that...
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 04, 2018, 01:27:23 am
Joe, you don't need to look further. Another thread posted today:
https://www.eevblog.com/forum/repair/fluke-87v-105223/ (https://www.eevblog.com/forum/repair/fluke-87v-105223/)
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on March 04, 2018, 01:38:40 am
Has anyone torn apart/tested one of the new AMES meters from Harbor freight ? Saw them today and they looked decent for an electricians meter, had a ETL listing as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 04, 2018, 04:17:47 am
MOVs would give up if limiar overvoltage is applied for too long - the circuitry could probably withstand 1.1~1.2kV, but the MOVs would suffer thermal stress. All in all, I don't think any meter would be too different in this regard (unless they used higher voltage MOVs).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 04, 2018, 05:07:30 am
Part 3

https://youtu.be/gSX04cEtl1A
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 04, 2018, 11:19:47 am
Exactly what I was thinking.  Can it really be this bad?   I was going to run the tests just for completeness but now I wonder if it is not even going to make it to the transient tests.

You could try it on your old, repaired one. That way nobody can accuse you of not using a pristine meter in the 'real' tests.

(are we really debating which test do do first because we're worried it might not survive any of them?)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 04, 2018, 12:54:40 pm
MOVs would give up if limiar overvoltage is applied for too long - the circuitry could probably withstand 1.1~1.2kV, but the MOVs would suffer thermal stress. All in all, I don't think any meter would be too different in this regard (unless they used higher voltage MOVs).

I've had people suggest similar things but it really makes no sense to me.  Maybe you could explain why you feel this way.  What is causing all of this thermal stress you mention?
If a MOV rated (loose definition of "rated" here) for 1kV is subjected to, say, 1.2kV, it will try to clamp this voltage differential using the only means it knows: by dissipating the surplus energy through its body. But that you already know.

In the scenario above, considering the output impedance of the source is low enough, the amount of the surplus energy that needs to be dissipated depends on the waveform. In a single pulse transient, the extra energy is perfectly contained with minor (if at all) stress to the MOV. On the other hand, a 1.2kVAC at 50 or 60 Hz will demand the MOV to continuously dissipate the energy contained in the upper and lower cycles of the sinewave. By the same logic and what was reported in the thread I mentioned, 1.2kVDC is the worst scenario as there is no time for the MOV to cool.

In the AC scenario (and to a much lesser extent to DC), the survivabilty of the MOV is highly dependent on its physical characteristics, as well as its environmental (temperature and humidity) and the surrounding heatsink ability of its PCB (large copper areas, clearance, etc.). That is why I mentioned that most (if not all) DMMs would have the same outcome as reported in the linked thread.
Title: Re: Handheld meter electrical robustness testing.
Post by: WhichEnt2 on March 04, 2018, 01:27:22 pm
They are changed 2 smd caps above the "fluke and linear" branded IC. On your video small caps are installed, but on early teardown photos they use big caps.
In my 87V which is manufactured at feb 2017 they are also small.


(https://lh6.googleusercontent.com/-SeVWgtFAosY/TjT9knK3f2I/AAAAAAAAGUs/1ZgLIZ2mX-g/s800/Fluke%25252087%252520V%252520rev%2525209%252520and%25252011%252520higher%252520res1.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 04, 2018, 02:37:03 pm
MOVs would give up if limiar overvoltage is applied for too long - the circuitry could probably withstand 1.1~1.2kV, but the MOVs would suffer thermal stress. All in all, I don't think any meter would be too different in this regard (unless they used higher voltage MOVs).

I've had people suggest similar things but it really makes no sense to me.  Maybe you could explain why you feel this way.  What is causing all of this thermal stress you mention?
If a MOV rated (loose definition of "rated" here) for 1kV is subjected to, say, 1.2kV, it will try to clamp this voltage differential using the only means it knows: by dissipating the surplus energy through its body. But that you already know.

In the scenario above, considering the output impedance of the source is low enough, the amount of the surplus energy that needs to be dissipated depends on the waveform. In a single pulse transient, the extra energy is perfectly contained with minor (if at all) stress to the MOV. On the other hand, a 1.2kVAC at 50 or 60 Hz will demand the MOV to continuously dissipate the energy contained in the upper and lower cycles of the sinewave. By the same logic and what was reported in the thread I mentioned, 1.2kVDC is the worst scenario as there is no time for the MOV to cool.

In the AC scenario (and to a much lesser extent to DC), the survivabilty of the MOV is highly dependent on its physical characteristics, as well as its environmental (temperature and humidity) and the surrounding heatsink ability of its PCB (large copper areas, clearance, etc.). That is why I mentioned that most (if not all) DMMs would have the same outcome as reported in the linked thread.
Because I am currently looking at the 87V,  let's just use it for an example.  A few things to consider.  The one MOV has a 1Meg resistor in series with it.  Even with 2KV applied, will limit the current to 2mA assuming the MOVs were shorted.    The second leg uses a PTC and surge rated resistor for the drive side.  With enough DC the PTC would eventually kick in but may not limit the current enough to prevent long term damage (assuming the secondary clamp is not engaged).    However...   

I think the standards require 1.1 times the meter's rating but I would need to double check that.  In any case the F87V uses S05K575 MOVs.  These have a 785VDC rating.   You have two in series.  So even if the voltage is at 1.5KVDC, the MOVs are not doing much of anything.  I've looked at a fair number of meters now.  Granted, there is some cheap junk out there but let's ignore that class.  For the meters rated for 1KV, looking over my note,  I don't see any that clamp a couple hundred over 1KV.   One meter was sort of a hybrid using a combination of GDTs and a MOV.   The MOV in this case had a DC rating of 670 volts.  However, the GDTs would not fire until 1200.  With a DC source, if you did manage to trip the GDTs they are going to stay on until the current drops which would put a strain on the MOV.  But again, we have to get he GDT to turn on in the first place.   

Obviously if the voltage was so high that the MOVs were conducting and we left it like this for an extended time, I fully agree that the MOV will degrade but I just don't see this happening at the sub 1.5KV. 

Assuming there is anything left of the 87V when I am done with it, I would be willing to attach it to a 1.2KVDC power supply and let it sit for a long term test.  Say a week with the meter in the DC volts setting.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 04, 2018, 03:41:56 pm
MOVs would give up if limiar overvoltage is applied for too long - the circuitry could probably withstand 1.1~1.2kV, but the MOVs would suffer thermal stress. All in all, I don't think any meter would be too different in this regard (unless they used higher voltage MOVs).

I've had people suggest similar things but it really makes no sense to me.  Maybe you could explain why you feel this way.  What is causing all of this thermal stress you mention?
If a MOV rated (loose definition of "rated" here) for 1kV is subjected to, say, 1.2kV, it will try to clamp this voltage differential using the only means it knows: by dissipating the surplus energy through its body. But that you already know.

In the scenario above, considering the output impedance of the source is low enough, the amount of the surplus energy that needs to be dissipated depends on the waveform. In a single pulse transient, the extra energy is perfectly contained with minor (if at all) stress to the MOV. On the other hand, a 1.2kVAC at 50 or 60 Hz will demand the MOV to continuously dissipate the energy contained in the upper and lower cycles of the sinewave. By the same logic and what was reported in the thread I mentioned, 1.2kVDC is the worst scenario as there is no time for the MOV to cool.

In the AC scenario (and to a much lesser extent to DC), the survivabilty of the MOV is highly dependent on its physical characteristics, as well as its environmental (temperature and humidity) and the surrounding heatsink ability of its PCB (large copper areas, clearance, etc.). That is why I mentioned that most (if not all) DMMs would have the same outcome as reported in the linked thread.
Because I am currently looking at the 87V,  let's just use it for an example.  A few things to consider.  The one MOV has a 1Meg resistor in series with it.  Even with 2KV applied, will limit the current to 2mA assuming the MOVs were shorted.    The second leg uses a PTC and surge rated resistor for the drive side. With enough DC the PTC would eventually kick in but may not limit the current enough to prevent long term damage (assuming the secondary clamp is not engaged).    However...   
That sums it up. I should have prefaced my post with the assumption the MOVs are directly in parallel with the inputs - in other words, I was completely illiterate about the 87V's input circuitry. :)

Assuming there is anything left of the 87V when I am done with it, I would be willing to attach it to a 1.2KVDC power supply and let it sit for a long term test.  Say a week with the meter in the DC volts setting.   
That would be an interesting test.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 04, 2018, 04:15:34 pm
That sums it up. I should have prefaced my post with the assumption the MOVs are directly in parallel with the inputs - in other words, I was completely illiterate about the 87V's input circuitry. :)

I saw a meter with a place holder for a MOV right across the inputs. I think it may have been sold by Tek Power.  The MOV was not populated for good reason.   Imagine the stress that would put on the leads, PCB, MOV....   If anyone ever comes across a handheld meter that uses a MOV without any additional limiting device/s, please let me know.

Assuming there is anything left of the 87V when I am done with it, I would be willing to attach it to a 1.2KVDC power supply and let it sit for a long term test.  Say a week with the meter in the DC volts setting.   
That would be an interesting test.
Consider it done.  I will need to set up some sort of containment so the inquisitive critters are kept safe.   Maybe measure the input impedance before and after the test.  Let me think about it.
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on March 04, 2018, 04:19:24 pm
If anyone ever comes across a handheld meter that uses a MOV without any additional limiting device/s, please let me know.

I have seen a spark gab across the input terminals, but I do not remember what meter it was.
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on March 04, 2018, 05:05:38 pm
I am VERY interested in knowing what meter this is. 

It was a cheap meter with the usually bogus CAT rating:

(http://lygte-info.dk/pic/cpf4/PeakmeterMS8248S.png)

My review: http://lygte-info.dk/review/DMMPeakmeter%20MS8248S%20UK.html (http://lygte-info.dk/review/DMMPeakmeter%20MS8248S%20UK.html)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 04, 2018, 05:20:31 pm
Speechless
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 04, 2018, 06:18:20 pm
No shunt? er.. maybe it's the fuse..  :-DD  I've seen nube's everywhere raving on any product that gets rid of that "nasty range switch"
Title: Re: Handheld meter electrical robustness testing.
Post by: Hydrawerk on March 04, 2018, 10:14:39 pm
OK, Fluke 87V is not a very good product. What about Fluke 289, 28II or 179??
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 05, 2018, 04:28:15 am
OK, Fluke 87V is not a very good product. What about Fluke 289, 28II or 179??

Does this look like a multimeter shootout thread or a "Which multimeter should I buy?" thread?  :-//

The 87V is supposedly the yardstick meter, the industry standard for excellence, the meter that can do no wrong.

So far joe's only unboxed it and noted a clunky user interface (how many secret power-on modes does it have?) and cheap fit and finish (poor plastics, bent shield).

Testing's not over yet. Not by a long way.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 05, 2018, 05:00:46 am
OK, Fluke 87V is not a very good product. What about Fluke 289, 28II or 179??

Does this look like a multimeter shootout thread or a "Which multimeter should I buy?" thread?  :-//

The 87V is supposedly the yardstick meter, the industry standard for excellence, the meter that can do no wrong.

So far joe's only unboxed it and noted a clunky user interface (how many secret power-on modes does it have?) and cheap fit and finish (poor plastics, bent shield).

Testing's not over yet. Not by a long way.
Yeah right !
You're new here aren't you ?

Tucked way back on P13 of this 100 pages of goodness:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg708183/#msg708183 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg708183/#msg708183)

2 1/2 years ago !
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 05, 2018, 05:23:44 am
The 87V is supposedly the yardstick meter, the industry standard for excellence, the meter that can do no wrong.
Yeah right !
You're new here aren't you ?

Tucked way back on P13 of this 100 pages of goodness:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg708183/#msg708183 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg708183/#msg708183)

Please pay attention.

There's a whole bunch of people who believe the Fluke 87V is perfect in every way, they insist the previous tests must have been done with faulty meters (or something).

The clue is at the top of the page you're reading:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=401014;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 05, 2018, 01:35:22 pm
Funny, that poll was a fair amount of time ago as well.   Yes, I have read several comments where people felt something was wrong.  Indeed, it may have been.  That's partly why I am doing this series in smaller chunks as well.  It gives people time to digest what is going on and ask questions. 

I still need to run the continuity tests and make sure I don't see any susceptible sweet spots.   Then it's onto more destructive testing.  My plan for the next part is to run the tests in the following order:

open fuse test
AC line
piezo grill starter
ESD gun
transient test to failure (if it can be repaired, I will go ahead and do that)
rotary switch cycle testing
long term 1.2KVDC for rsjsouza
Fungus like the drop tests so I may drop this thing on the block of wood as well

Again, all of this could change depending how the testing goes....
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on March 05, 2018, 02:34:33 pm
Depending on the order you might be able to put Flukes warranty to the test at the same time.   :o :-BROKE
Title: Re: Handheld meter electrical robustness testing.
Post by: ChrisLX200 on March 05, 2018, 02:57:08 pm
Funny, that poll was a fair amount of time ago as well.   Yes, I have read several comments where people felt something was wrong.  Indeed, it may have been.  That's partly why I am doing this series in smaller chunks as well.  It gives people time to digest what is going on and ask questions. 

I still need to run the continuity tests and make sure I don't see any susceptible sweet spots.   Then it's onto more destructive testing.  My plan for the next part is to run the tests in the following order:

open fuse test
AC line
piezo grill starter
ESD gun
transient test to failure (if it can be repaired, I will go ahead and do that)
rotary switch cycle testing
long term 1.2KVDC for rsjsouza
Fungus like the drop tests so I may drop this thing on the block of wood as well

Again, all of this could change depending how the testing goes....

You forgot the flame-thrower test, and maybe Truck test (run it over with your car and see if it still works) :)
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on March 05, 2018, 11:17:40 pm
I'm sure Joe has a few guns too.  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 06, 2018, 01:12:57 am
I'm sure Joe has a few guns too.  >:D

I could shoot it with my fuse powered cork gun.    :-DD
Piezo ignitor and Methanol upgrade required ?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 06, 2018, 10:52:23 am
After seeing the bent shield in my brand new Fluke 87V, a member with a slightly older 87V took theirs apart and provided me with this picture.  I had hoped the meter I received was a one off mistake but it appears they are bending the shield and no one is catching it.  I have not yet done anymore with the 87V and it's still sitting in parts.  The shield looks like it is designed to sit flat.  I can place it flat in the board.   The two tabs seem to be setup correctly.    Maybe they cut their QC staff to make more money?  Maybe it's supposed to be bent?   

Too bad these large companies have no presence in these groups.   If it were Brymen, I would just ask them and based on all my previous experiences with them, would have an answer in a day.  I never found a contact at Danaher/Fluke.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 06, 2018, 12:09:20 pm
Maybe it's deliberate.

Does it press against the back of the case like a spring? Does it look like there's any reason to do that?

I can place it flat in the board.

Doesn't necessarily mean it's supposed to be like that.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 06, 2018, 12:14:16 pm
Dave's running a live switch cycle on his second channel.  I watched it for a few minutes.  Tried to calculate the resistance with the formulas shown but looks like its 1.7K ohms the one way  a little better the other.  Guessing I am missing something as I think he said they could only read up to 10 ohms or so.   So much computing power and they resort to sticky notes.   :palm:

He also cleaned off the accumulated dust/debris after every bunch of cycles.  :scared:

If that's fiberglass dust then it's an abrasive, just sayin'.
Title: Re: Handheld meter electrical robustness testing.
Post by: ChrisLX200 on March 06, 2018, 12:22:40 pm
Dave's running a live switch cycle on his second channel.  I watched it for a few minutes.  Tried to calculate the resistance with the formulas shown but looks like its 1.7K ohms the one way  a little better the other.  Guessing I am missing something as I think he said they could only read up to 10 ohms or so.   So much computing power and they resort to sticky notes.   :palm:

He also cleaned off the accumulated dust/debris after every bunch of cycles.  :scared:

If that's fiberglass dust then it's an abrasive, just sayin'.

I don't think it's fiberglass - solder mask more likely. In normal use the meter would be picked up and put down potentially dislodging the dust anyway after every use or so - you cannot replicate normal usage easily. These sorts of test can only ever be a rough guide to wear rate, and you would need to test many to get some sort of average.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 06, 2018, 12:57:58 pm
Maybe it's deliberate.

Does it press against the back of the case like a spring? Does it look like there's any reason to do that?

I can place it flat in the board.

Doesn't necessarily mean it's supposed to be like that.

It's held in place by the screws.  It does not appear to spring off the back of the case.  It looks like it was designed to fit flat. There are no clearance issues I see with that would prevent it from sitting flat.  I see no reason for it to be bowed other than poor quality control.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 06, 2018, 01:24:18 pm
Dave's running a live switch cycle on his second channel.  I watched it for a few minutes.  Tried to calculate the resistance with the formulas shown but looks like its 1.7K ohms the one way  a little better the other.  Guessing I am missing something as I think he said they could only read up to 10 ohms or so.   So much computing power and they resort to sticky notes.   :palm:

He also cleaned off the accumulated dust/debris after every bunch of cycles.  :scared:

If that's fiberglass dust then it's an abrasive, just sayin'.

I don't think it's fiberglass - solder mask more likely. In normal use the meter would be picked up and put down potentially dislodging the dust anyway after every use or so - you cannot replicate normal usage easily. These sorts of test can only ever be a rough guide to wear rate, and you would need to test many to get some sort of average.

I was under the impression that this round of testing was done live, non-stop, 50K half cycles, no cleaning with the shim installed correctly.  I only saw the last few minutes so if you saw him cleaning it again, that's a problem.   If your pulling that out of your ass and don't really know, we should ask Dave.   

I don't need to run more of the same meter to see the difference in wear.   Between the pictures and resistance metric, it's good enough for me.   Some have certainly cut deeper than mask.  Then there is that detent spring, it's not always the contacts that are the problem.       

Then again, I have been told many times that I can't draw a conclusion from the transient tests I run because the sample size is one. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 06, 2018, 01:47:32 pm
It's held in place by the screws.  It does not appear to spring off the back of the case.  It looks like it was designed to fit flat. There are no clearance issues I see with that would prevent it from sitting flat.  I see no reason for it to be bowed other than poor quality control.

So basically the metal tabs in the middle of the shield just weren't in their PCB holes?

Oh, dear.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 06, 2018, 03:50:51 pm
I foresee the used test gear market will start categorizing 87Vs between pre- and post- a specific serial#... That or photographs of the back of the meters will become almost mandatory.

IMHO every reaction is sparked by a previous action - as I said before, due to the amount of competition on the 20k count segment I honestly believe the 87V's sales figures can't support the margins it once had.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 06, 2018, 04:36:04 pm
IMHO every reaction is sparked by a previous action - as I said before, due to the amount of competition on the 20k count segment I honestly believe the 87V's sales figures can't support the margins it once had.

Sure, but they're not lowering the prices and I can't believe the cost of manufacturing them is going up.

This is just bean counting of the very worst kind. John Fluke must be doing about 12 RPM right now.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on March 07, 2018, 01:12:40 am
After seeing the bent shield in my brand new Fluke 87V, a member with a slightly older 87V took theirs apart and provided me with this picture.  I had hoped the meter I received was a one off mistake but it appears they are bending the shield and no one is catching it.  I have not yet done anymore with the 87V and it's still sitting in parts.  The shield looks like it is designed to sit flat.  I can place it flat in the board.   The two tabs seem to be setup correctly.    Maybe they cut their QC staff to make more money?  Maybe it's supposed to be bent?   

Too bad these large companies have no presence in these groups.   If it were Brymen, I would just ask them and based on all my previous experiences with them, would have an answer in a day.  I never found a contact at Danaher/Fluke.

The clearances from shiield to the HV input circuit parts looks bad?
The leads on the MOVs', 1k resistor etc. there should be a insulating barrier ?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 07, 2018, 01:35:24 am
After seeing the bent shield in my brand new Fluke 87V, a member with a slightly older 87V took theirs apart and provided me with this picture.  I had hoped the meter I received was a one off mistake but it appears they are bending the shield and no one is catching it.  I have not yet done anymore with the 87V and it's still sitting in parts.  The shield looks like it is designed to sit flat.  I can place it flat in the board.   The two tabs seem to be setup correctly.    Maybe they cut their QC staff to make more money?  Maybe it's supposed to be bent?   

Too bad these large companies have no presence in these groups.   If it were Brymen, I would just ask them and based on all my previous experiences with them, would have an answer in a day.  I never found a contact at Danaher/Fluke.

The clearances from shiield to the HV input circuit parts looks bad?
The leads on the MOVs', 1k resistor etc. there should be a insulating barrier ?
You know, it does look bad in that picture they sent me.  There's that tab on the backside that should hold it away from the board and I have not looked but I don't think the shield extends down far enough.  That said, nothing says they did not change the shield design.  There meter is older than mine.  This same person has an older version of the meter and they said the shield was made differently in the earlier models.  They said they would provide me with a picture of that one for comparison.  I will post it once I have it.   

It could be a Gossen and have no shield and be unstable as you move your hand near it, expose it to RF, or have relays that change states when exposed to a magnetic hanger.  All preventable with a good shield design.    The things we can learn with a sample size of one! 

Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on March 07, 2018, 04:52:28 am
Dave's running a live switch cycle on his second channel.  I watched it for a few minutes.  Tried to calculate the resistance with the formulas shown but looks like its 1.7K ohms the one way  a little better the other.  Guessing I am missing something as I think he said they could only read up to 10 ohms or so.   So much computing power and they resort to sticky notes.   :palm:

He also cleaned off the accumulated dust/debris after every bunch of cycles.  :scared:

No I did not.
The latest test was 50,000 cycles with no interruptions. You are welcome to watch the entire 23 hours video once Youtube has finished processing it, assuming it actually can process a 23hr live stream.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 07, 2018, 07:07:51 am
He also cleaned off the accumulated dust/debris after every bunch of cycles.  :scared:

No I did not.

What happened at the 12 minute mark?

https://www.youtube.com/watch?v=u2-ot2vWLxI&t=12m0s (https://www.youtube.com/watch?v=u2-ot2vWLxI&t=12m0s)

Quote: "A bit of spit on that..."

The latest test was 50,000 cycles with no interruptions.

Fair enough.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 07, 2018, 01:05:01 pm
He also cleaned off the accumulated dust/debris after every bunch of cycles.  :scared:

No I did not.

What happened at the 12 minute mark?

Quote: "A bit of spit on that..."

Fair enough.
Previous test was all.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 07, 2018, 01:09:18 pm
These are the pictures showing the older Fluke 87V shield design.   I would think the stamped shield would be less costly to produce.  I have asked for a picture showing the stamped shield from the backside to see if they changed the profile. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2018, 02:16:42 am
It appears their older 87V's shield is identical to the one supplied with mine.  It sure looks like their tab was not pushed through the slits when the shield was installed.  It's too bad Fluke reps don't hang out here.  It seems like something they would want to know about, then again, it seems like it has been a problem for a long time so hard to believe the supervisor's and QC are not aware of it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on March 08, 2018, 02:30:04 am
It appears their older 87V's shield is identical to the one supplied with mine.  It sure looks like their tab was not pushed through the slits when the shield was installed.  It's too bad Fluke reps don't hang out here.  It seems like something they would want to know about, then again, it seems like it has been a problem for a long time so hard to believe the supervisor's and QC are not aware of it.

You don't need to test a product for quality if lack of quality does not affect your sales. It's not cost-effective.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2018, 03:03:51 am
It appears their older 87V's shield is identical to the one supplied with mine.  It sure looks like their tab was not pushed through the slits when the shield was installed.  It's too bad Fluke reps don't hang out here.  It seems like something they would want to know about, then again, it seems like it has been a problem for a long time so hard to believe the supervisor's and QC are not aware of it.

You don't need to test a product for quality if lack of quality does not affect your sales. It's not cost-effective.
True but wouldn't take much more than the line supervisor looking at one and showing the worker how to properly install them.  If their supervisor can't handle something that basic, I would say they have the wrong person in that position.  But it may be cheep labor.  Or maybe unsupervised.  Surly the workers must think, that part should fit flat and maybe I should try and slid that tab into that slit....  Crazy...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 08, 2018, 01:16:51 pm
You don't need to test a product for quality if lack of quality does not affect your sales. It's not cost-effective.

Yep. If large corporations are buying these by the truckload without ever looking inside then what's the point? Got a problem? send it back.

Fluke can probably absorb 50% returns under warranty and still make a profit on these things.

(Maybe more: What's the BOM? About $50 I imagine... what's the next most expensive thing after the fuses and the precision resistors? The leads?)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 09, 2018, 12:18:19 am
You don't need to test a product for quality if lack of quality does not affect your sales. It's not cost-effective.

Yep. If large corporations are buying these by the truckload without ever looking inside then what's the point? Got a problem? send it back.

Fluke can probably absorb 50% returns under warranty and still make a profit on these things.

(Maybe more: What's the BOM? About $50 I imagine... what's the next most expensive thing after the fuses and the precision resistors? The leads?)

What was the cost to have the custom IC made?  Burden?  Certifications?
If it follows other meters from Fluke, it is probably a MSP430 with clipped JTAG and a custom P/N. I don't recall ever seeing a larger MSP430 ROM masked. If that is correct, the cost for the customization itself is no different than a commercial part, only the volume counts.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 09, 2018, 01:11:11 am
If it follows other meters from Fluke, it is probably a MSP430 with clipped JTAG and a custom P/N. I don't recall ever seeing a larger MSP430 ROM masked. If that is correct, the cost for the customization itself is no different than a commercial part, only the volume counts.

I doubt that the front end is something you program with JTAG?  I expect it to be a full custom, mixed mode IC developed exclusively for Fluke, possibly by Fluke.  I doubt it's just a remarked device but I don't know.  We could ask a Fluke rep but they don't seem to hang around the forums. 

Starting to work on Part 4.
Starting to work on Part 4. repairing it again ?  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 09, 2018, 01:38:57 am
Ha! Speaking of repairs.. Bigclive just made a video on Fluke recalling the SM100/200/300 plug-in testers. After Joe pops the brains out of this one, me thinks John Fluke Sr will be turning.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 09, 2018, 09:01:09 am
I doubt that the front end is something you program with JTAG?  I expect it to be a full custom, mixed mode IC developed exclusively for Fluke, possibly by Fluke.  I doubt it's just a remarked device but I don't know.

Design/development costs for the chip will have been recovered a long time ago.

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 09, 2018, 09:55:41 am
It may surprise us and survive everything.   What a twist that would be as it sounds like the majority feel it is just doing to fail the same.  I don't think one person has told me they thought it was going to do well since I started.   What's that tell you.   Surly I have not shaken the confidence of the countless  Fluke 87V fans.     

The eyes of the world are on you, joe.

(...and if it does worse than a 17B+ then something is very wrong)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 09, 2018, 09:59:00 am
What was the cost to have the custom IC made?
The first batch of ICs would have been very expensive. A $400 price tag was probably justified.

Today? Not so much. I'd be surprised if the chip costs as much as the fuses. It's not a complex chip by today's standards and the R&D was done long ago.

(could any experts add anything here?)
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on March 09, 2018, 11:41:06 am
if things are like 20 years ago, the most expensive bits may well be the injection-moulded plastic parts!!
that stuff costs a lot because the moulds are a bitch to make, and they dont last forever.
also, the parts must be hand-finished afterwards to get rid of tails and stuff.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 09, 2018, 12:53:58 pm
This is the king of meters, why aren't people saying it was all a Fluke and how the 87V is going to surpass every Fluke I have looked at?  Where is the confidence I keep hearing about?   

There's a reason you drew a demon on your zapper...  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 09, 2018, 06:27:45 pm
If it follows other meters from Fluke, it is probably a MSP430 with clipped JTAG and a custom P/N. I don't recall ever seeing a larger MSP430 ROM masked. If that is correct, the cost for the customization itself is no different than a commercial part, only the volume counts.

I doubt that the front end is something you program with JTAG?  I expect it to be a full custom, mixed mode IC developed exclusively for Fluke, possibly by Fluke.  I doubt it's just a remarked device but I don't know.  We could ask a Fluke rep but they don't seem to hang around the forums. 

Starting to work on Part 4.
Oh, were you referring to the front end? I was talking about the main processor IC, which years ago it used to be a MSP430 but I didn't keep current with the latest models (thus it could have been morphed into a custom-looking part).
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 10, 2018, 02:48:40 am
Smoke was rolling out of the 87V tonight and I'm not even to the fun stuff yet....
:scared: That was bait and you know it..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2018, 03:54:41 am
Smoke was rolling out of the 87V tonight and I'm not even to the fun stuff yet....
:scared: That was bait and you know it..
Just keeping you in the loop.    I thought people on this forum liked getting the second by second updates....  :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: geekGee on March 10, 2018, 06:10:39 am
I don't know about all of that.  My channel is tiny.  About 10% of the followers will view it.  Of those, about 10% will rate it.  It's down in the noise floor somewhere, where it belongs.   

Well I guess that makes me 10% of the 10%.  I thoroughly enjoy your videos.  I will admit when I watch them I often think to myself that I should be bored but I find them fascinating.

And I am not an EE... I'm a lowly 30 year veteran in IT with a recent interest in electronics.

I do own an 87V I purchased in 2014 so am looking forward to your next installment.  I bought it to supplement my 83 (no suffix) which I think I bought around 1990.

Keep up the good work Joe!!!
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 10, 2018, 09:15:51 am
Smoke was rolling out of the 87V tonight and I'm not even to the fun stuff yet....

It failed the AC line test?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2018, 12:16:36 pm
Smoke was rolling out of the 87V tonight and I'm not even to the fun stuff yet....
It failed the AC line test?
To be clear, I wouldn't necessarily consider smoke rolling out a failure.   They should have seen the smoke when the meter was certified.  If the agencies are all fine with it, so am I.    Of course I have done far worse to meters during this particular test and no smoke.  Possible feature. 
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on March 10, 2018, 01:35:59 pm
....  Possible feature. ....

ROLFMAO  :-DD

Fluke 87 VI  NAE (Native American Edition) with built in smoke signals...........
Title: Re: Handheld meter electrical robustness testing.
Post by: ProBang2 on March 10, 2018, 01:48:08 pm
Smoke was rolling out of the 87V tonight and I'm not even to the fun stuff yet....
:scared: That was bait and you know it..
Just keeping you in the loop.    I thought people on this forum liked getting the second by second updates....  :-DD   

If anyone is out there who don´t know the meaning of the german expression "Salami Taktik" - that´s the perfect example to explain it...    :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2018, 02:41:12 pm
Smoke was rolling out of the 87V tonight and I'm not even to the fun stuff yet....
:scared: That was bait and you know it..
Just keeping you in the loop.    I thought people on this forum liked getting the second by second updates....  :-DD   
If anyone is out there who don´t know the meaning of the german expression "Salami Taktik" - that´s the perfect example to explain it...    :-DD
https://en.wikipedia.org/wiki/Salami_tactics
Quote
Salami tactics, also known as the salami-slice strategy or salami attacks,[1] is a divide and conquer process of threats and alliances used to overcome opposition. With it, an aggressor can influence and eventually dominate a landscape, typically political, piece by piece. In this fashion, the opposition is eliminated "slice by slice" until one realizes (too late) that it is gone in its entirety. In some cases it includes the creation of several factions within the opposing political party and then dismantling that party from the inside, without causing the 'sliced' sides to protest. Salami tactics are most likely to succeed when the perpetrators keep their true long-term motives hidden and maintain a posture of cooperativeness and helpfulness while engaged in the intended gradual subversion.

Quote
a gradual attack on an opposing position, group, etc.

That's your perspective.  I was fully content to say the 87V was just not a very robust meter.  Anyone who does a search just on this website would see a fair number of damaged 87Vs.  But for what ever reason, that was not good enough for a fair number of people who asked that I look at one more.   

I fully admit to showing the data in small increments or slices.  If I were getting paid by YT, it would be one way to raise more money but seeing I don't use ads and such there is nothing to be financially gained.   What it does do is provide the people who wanted to see another one,  an opportunity to digest the data and ask questions.   

I really have no long term hidden agenda beyond just seeing how the various meters perform to some standard method of testing and maybe helping educate people about how the meters are designed and not to do stupid things with them.     Hard to say if I made any dent in the later. 

(really poor wording, spelling.....)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2018, 04:11:37 pm
Part 4,  Looking at the shield problem, testing the current inputs and ESD testing.  I also answer another question.     

https://youtu.be/ar23yj3YOHw
Title: Re: Handheld meter electrical robustness testing.
Post by: ProBang2 on March 10, 2018, 04:15:41 pm
No offense intended.  :-//

But giving informations slice by slice, probably leading to a big surprise (at least for some fanboys), that is "Salami Taktik".
Hence the last postings in this thread are a far, far better example for the explanation of this expression as it is used in the dayly language than a wiki article (reduced to the strict military meaning). 

Enough OT, I assume. Back to topic:
Time for the next slice of information???

PS.: I´m obviously not up to date. Happy to see your new video. Oh, this suspense...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2018, 05:14:37 pm
No offense intended.  :-//

But giving informations slice by slice, probably leading to a big surprise (at least for some fanboys), that is "Salami Taktik".
Hence the last postings in this thread are a far, far better example for the explanation of this expression as it is used in the dayly language than a wiki article (reduced to the strict military meaning). 

Enough OT, I assume. Back to topic:
Time for the next slice of information???

PS.: I´m obviously not up to date. Happy to see your new video. Oh, this suspense...
That is very interesting.   I could not find the exact match "Salami Taktik" but the military origins is what came up. 

Transient tests, the life cycle the switch, long term MOV test and drop are still to come. 

The transient tests could take a full day, or just a few seconds.   Life cycle is 2.5 days.  MOV will be another week.   

I have been thinking about the MOV test and am still on the fence if I just want to record the leakage before and after or maybe measure it over time using the PC.  Maybe have some yellow sticky notes with formulas and let you guess the actual conversions...   :-DD    Any suggestions on what you would like to see is fine. 

My guess is we won't see anything happen at the 1.2KV level.  If we do, maybe I will run that BM869s that Brymen sent.  I have been thinking about other ways to test it against the F87V anyways because it seems that is what the following discussion boiled down to.  That's what I took away from it.

https://www.eevblog.com/forum/testgear/if-brymen-bm869s-is-cheaper-and-as-good-why-people-would-still-buy-fluke/ (https://www.eevblog.com/forum/testgear/if-brymen-bm869s-is-cheaper-and-as-good-why-people-would-still-buy-fluke/)     
 


Title: Re: Handheld meter electrical robustness testing.
Post by: ConnorGames on March 10, 2018, 07:37:20 pm
With all of the love that the BM869s seems to be getting here, I figured you might want to investigate a potentially dangerous failure mode I encountered with mine about a year ago. The metal locking ring came loose from the back of the range switch shaft and was left floating around the inside of meter. I don't know exactly how much of an impact a piece of metal this size would have on the safety of the meter, but it was certainly worrying.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 10, 2018, 08:01:09 pm
With all of the love that the BM869s seems to be getting here, I figured you might want to investigate a potentially dangerous failure mode I encountered with mine about a year ago. The metal locking ring came loose from the back of the range switch shaft and was left floating around the inside of meter. I don't know exactly how much of an impact a piece of metal this size would have on the safety of the meter, but it was certainly worrying.
While I normally try to steer this blog away from safety, surely any loose metal would be a concern for anyone.   We have nothing to go by other than what you wrote.  I can offer that I have taken mine apart a few times and that clip was a pain to get off of there.  It's the first I have heard of one coming off, on any meter.  Did you buy the meter new?  Had you taken it apart before?  I assume you reinstalled it.  Did it lock into place or was it loose?  Did you take pictures to document this and then contact Brymen about it and if so, what was their response?   I would appreciate hearing their response and any other details you care to share about it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 11, 2018, 11:22:45 pm
Attempting to overcome the lack of equations with more post-its.    No doubt this test will go very smoothly. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 12, 2018, 12:24:22 am
A person had posted the attached bone to pick with me after posting my last video.   This is in regards to my cutting open the HRC fuse.  I've attempted to look at the clearance and creepage for the current inputs before.  I don't have a 500VA supply as the standard calls for but I am really just interested in seeing if anything starts to breakdown at the 2X level.    In the case of the 87V, I really don't like that sleeved battery wires running between the fuse holders, however at least at 2KV it does not seem to have a problem with it. 

That said, one comment they made I found of interest:
Quote
You performed a completely useless test by emptying the fuse out. It's simulating a fault which would not exist. In the field you either have an intact fuse, or a blown one.

Does a fuse really only have two state?   For fun, if I take say an inch of some 30 AWG wire and connect it to my 20A power supply, then slowly increase the current until the wire opens you may find that the point where it breaks that the wires are still very close to one another.   This is how I opened up the fuse that I used for these tests and when I cut open the fuse, the filament was still mostly there.  No molten filler and such.   So when I attempted to apply a few KV to it, it would light up. 

Had I connected this same fuse to my half cycle simulator, I suspect there would be nothing left of the filament and the fuse would not have broke over at the 2KV test voltage.  I've made a few videos showing various fuses being blown with various levels of energy.   I doubt anyone here would believe connecting my fuse powered rocket to a 100A, 2V power supply would get it to lift off.   It may actually be possible to get it to be an open to the 2V supply but still be able to launch.   Similar to how I test the meters, if I apply a 5KV pulse and it arcs over, then feed the energy from the half cycle simulator into it....  Well, maybe.

Anyway, I don't believe there are just two states.   

https://youtu.be/xLDok9Sm07Q?t=117
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 12, 2018, 12:38:35 am
It's alright Joe, it was as plain as day (to me) what you were trying to accomplish......that sleeved battery cable running through the fuse holder would give me the heebie jeebies too !  :scared:
IMO, it's a desperate design repair bodge.

My Dr. EE lecturer (retired) mate would describe it as 'gawd awful' !


He didn't so much carry just one bone to pick with you, he was carrying a whole graveyards's worth.  ::)
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on March 12, 2018, 12:41:15 am
I can confirm that those fuses don't always blow with a high energy mistake.

I broke my duck the other week and blew a multimeter fuse for the first time in my life. To my intense annoyance it was one of the expensive fuses in my BM869s. That'll teach me to be careless with my measurements  :)

Anyway, to cut a long story short I was measuring the current in various lamps to compare with the reading from a Kill A Watt clone I bought, testing for accuracy. Looking at various LED and CFL lamps, I was using the 500 mA range. Then I moved over to some incandescent lamps, and I connected what I thought was a 60 W lamp. Unfortunately it was a 100 W lamp and pop went the fuse  :(

I did not enjoy having to spend $8 to replace the fuse, but I doubt the fuse wire was vaporized or had much of a gap in it. I suppose I could break open the fuse to find out...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 12, 2018, 01:29:30 am
I have seen a few cases where a similar sleeve has been used.   The attached is showing my CEM meter where they use it to route the common return for the high current mode.  Good layouts are works of art. 

I did not enjoy having to spend $8 to replace the fuse, but I doubt the fuse wire was vaporized or had much of a gap in it. I suppose I could break open the fuse to find out...

In the name of science, I would and then post a few pictures.  The woven fuse I show could be cut with my wife's shears with ease.  Maybe just a sharp knife to reduce damaging the evidence.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Daruosha on March 12, 2018, 11:31:13 am
No offense intended.  :-//

But giving informations slice by slice, probably leading to a big surprise (at least for some fanboys), that is "Salami Taktik".
Hence the last postings in this thread are a far, far better example for the explanation of this expression as it is used in the dayly language than a wiki article (reduced to the strict military meaning). 

Enough OT, I assume. Back to topic:
Time for the next slice of information???

PS.: I´m obviously not up to date. Happy to see your new video. Oh, this suspense...

He's doing a very comprehensive and detailed series of test and I think we all understand these tests take time. Chemical test, assembly analyze, detailed functional test, trying each and every feature and compare to other equivalent competitors and so on.

What I admire about joeqsmoth is his sophisticated approach to test the meters. As far as I remember, no one in the industry has done such a set of massive experiments and tests over the broad range of multimeters.

In fact I'd love more detailed tests like what he's doing with fluke 87V, and I find huge learning values in each episode (it's me and how I see the EE world).


BTW, i took 5 fluke 87V's apart, purchased from many years ago to last month, and all of them had bent shields. I guess no one in the assembly line gave a toss about it.

Thanks Joe and please keep up the good work.

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 12, 2018, 12:10:05 pm
BTW, i took 5 fluke 87V's purchased from many years ago to last month, and all of them had bent shields. I guess no one in the assembly line gave a toss about it.

The only way that's possible is if there's been:
a) no quality control at all for five years (and the exact same stubborn worker putting them together),
or
b) It's by design.

Neither of those makes any sense to me.  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on March 12, 2018, 12:26:20 pm
Or it was being put in by automated process (machine)  that is not setup right.  And there is tendency not to do detailed QC in that  case because machines don't make mistakes 😒
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 12, 2018, 02:44:43 pm
Or it was being put in by automated process (machine)  that is not setup right.  And there is tendency not to do detailed QC in that  case because machines don't make mistakes 😒

When I say "worker" I include machines.  :)

("robot" comes from the Czech word for "worker")
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on March 12, 2018, 03:56:24 pm
Or it was being put in by automated process (machine)  that is not setup right.  And there is tendency not to do detailed QC in that  case because machines don't make mistakes 😒

When I say "worker" I include machines.  :)

("robot" comes from the Czech word for "worker")

I know :-)    "rabota" is valid word in Croatian ...... Kind of archaic, but valid...

Anyways, my experience is that managers tend to skimp on QA if it was assembled on robots.... They rely on hope that automated process is well tuned and will produce within parameters...
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on March 12, 2018, 04:20:03 pm
or
b) It's by design.

This is somehow looking more likely. Maybe it's a "tamper evident" feature? Anyone who takes the meter apart is likely to reassemble it "properly" and therefore leave evidence that they disassembled it. Stranger things have happened...
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on March 12, 2018, 05:27:26 pm
or
b) It's by design.

Maybe it's a "tamper evident" feature? Anyone who takes the meter apart is likely to reassemble it "properly" and therefore leave evidence that they disassembled it.

LOL! A trap for engineers.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on March 13, 2018, 03:53:08 am
Did you cut up that fuse? If so, what did you find?

It was difficult to find much at all except sand. When I cut it in half in the middle and tipped the sand out the inside of the tube was too dark to make anything out. Trying to shine a light and a magnifier at the same time revealed very little. I think the fuse wire was much thinner than a human hair. Further attempts at disassembly destroyed whatever evidence remained. My guess is that the wire melted with quite a large gap in the middle.
Title: Re: Handheld meter electrical robustness testing.
Post by: LazyJack on March 13, 2018, 02:25:04 pm
I've just opened up my ~2 years old 87V (fw v3.03). The shielding is not bent, it is solidly in its place. Maybe versions for Europe are better built as people are used to German cars and wouldn't accept sloppy body work ;D?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 13, 2018, 02:46:43 pm
Re: The shield

Could the shield tabs pop out under vibration? Maybe give it a few whacks.

Seems like a long shot, but...  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 13, 2018, 04:59:33 pm
Did you cut up that fuse? If so, what did you find?

It was difficult to find much at all except sand. When I cut it in half in the middle and tipped the sand out the inside of the tube was too dark to make anything out. Trying to shine a light and a magnifier at the same time revealed very little. I think the fuse wire was much thinner than a human hair. Further attempts at disassembly destroyed whatever evidence remained. My guess is that the wire melted with quite a large gap in the middle.

The one I had used for these tests was a high current one.  The filament was fairly thick and I blew it with a low voltage supply.  There was a fair bit of evidence left after cutting it open.   Too bad we could not learn anything more from yours but thanks for taking the time to look. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 15, 2018, 12:48:28 pm
I plan to run the transient tests in the next few days.   If it goes to plan, I may just combine all the remaining tests into one video..     I'm not going to do a 10 day live feed of the meter sitting on a high voltage supply and cycling a switch.  :-DD   Combined, I can't see that being more than 15 minutes of footage total.  With the 15 minutes it will take to run the 87V at 1.5 and maybe 2, swap out a few diodes, should make for a good conclusion.   

My guess, meter fails at 2K, MOVs don't do anything with 1.2K applied for extended period, after a true 50K cycle test, the 87V will not need some sort of cleaning at 10K intervals and will be as clean as the 17B+ and about the same wear.   I may actually check this.... 

Then again, it is the latest rev of PCB.  Maybe Danaher let them spend some money and they changed something to offset the sloppy shield assembly and poor quality boot...  Go Fluke! 
https://youtu.be/v3bBgsqFZT8

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 15, 2018, 06:52:23 pm
joeqsmith, I can't wait for the 87V tests.

BTW, nice doodles of the MOVs and Uni-T. :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 17, 2018, 02:01:12 am
A few of you wanted to see another Fluke 87V ran.  So here is the latest Rev 13 hardware right from Fluke.  Enjoy.   

https://youtu.be/po7UEXLy0vU
Title: Re: Handheld meter electrical robustness testing.
Post by: don.r on March 17, 2018, 04:51:00 am
Shocking how much better this rev is! Absolutely shocking! (see what I did there?)
Title: Re: Handheld meter electrical robustness testing.
Post by: Towger on March 17, 2018, 09:03:48 am
The Fluke fan boys will be happy again.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 17, 2018, 03:12:30 pm
If I decided to attempt to further harden the meter, looking at how they have this front end, it seems like the easiest thing would be to find some replacement parts.  So far, no luck in hunting down a drop-in.  If you look at the sketch I made of the front end, those resistors connect to the custom IC.  Guessing the diodes provided better leakage and breakdown specs.  Maybe you could wrap around that diode circuit with a couple of TVSs but it would not be clean.   Then again, it's not like it failed at low levels like the older 87Vs, so I am less inclined to modify it.   

The Fluke fan boys will be happy again.
That 87V was always a bit odd with how poorly it did compared with all the other Flukes I had looked at.   For the 10 people who took the time to vote for seeing it, good on you.  I wouldn't have considered running it again.   

Still more testing to go but I don't see any reason the 87V will have problems.  I may have just jinxed it.  Watch the PCB get ground to dust after the MOVs burst into flames.  :-DD

It would be interesting to know more about why Fluke uses what appears to nickle finish rather than gold of nothing at all.   I wonder if that plating the key to why the 17B+ did so well.  After 50K full cycles, that meter hardly looked like it had been cycled.   Maybe new tooling played a part as well. 
Title: Re: Handheld meter electrical robustness testing.
Post by: jordanp123 on March 17, 2018, 07:14:34 pm
Any details on what fluke changed with this PCB revision ? If thats already been posted, I apologize, I searched but didn't find it.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on March 17, 2018, 08:06:49 pm
gold is soft and gets worn through pretty fast on things like pcb contacts for edge connectors.
maybe they used something harder.
Title: Re: Handheld meter electrical robustness testing.
Post by: zaoka on March 18, 2018, 03:03:12 pm
Will installing better substitutes of BAV diodes improve protection circuit, if so what diode should be used?

Is it time for Fluke 28II ??  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 22, 2018, 12:10:20 am
Finishing up rsjsouza's MOV testing.  Hope to post it along with the life cycle results this weekend.  I have included a link to Motorola's paper "TVS/Zener Theory and Design Considerations" which may be of interest. 

There may still be a part 7.  It may be worth seeing if we can determine why the previous 87V failed at such a low level compared with this latest revision.  Then again, maybe it is not important.  As Dave has said, they only fail on my tests, not in the field.  I will leave it up to viewer's to decide if you want to see it. 

http://www.icbase.com/File/News/download/ON_Reference_3.PDF (http://www.icbase.com/File/News/download/ON_Reference_3.PDF)
Title: Handheld meter electrical robustness testing.
Post by: kcbrown on March 22, 2018, 05:39:38 am
I'd love to see why the first 87V failed.  Should make for an interesting and likely instructional video.

That why it failed might not be important, er, isn't important.   :D


Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 22, 2018, 03:25:23 pm
Finishing up rsjsouza's MOV testing.  Hope to post it along with the life cycle results this weekend.  I have included a link to Motorola's paper "TVS/Zener Theory and Design Considerations" which may be of interest. 

There may still be a part 7.  It may be worth seeing if we can determine why the previous 87V failed at such a low level compared with this latest revision.  Then again, maybe it is not important.  As Dave has said, they only fail on my tests, not in the field.  I will leave it up to views to decide if you want to see it. 

http://www.icbase.com/File/News/download/ON_Reference_3.PDF (http://www.icbase.com/File/News/download/ON_Reference_3.PDF)
Thanks for the testing, Joe. I hope the MOV test reveals yet another interesting aspect of endurance - something I have experienced in other low cost meters: MOV or thermistors either cracked or severely burnt.

Regarding the usefulness of investigating an older production 87V: if there is evidence of a design change that triggered the premature failure, that will at least help educate the used market to look for specific traits of older production runs. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 22, 2018, 11:51:52 pm
Thanks for the testing, Joe. I hope the MOV test reveals yet another interesting aspect of endurance - something I have experienced in other low cost meters: MOV or thermistors either cracked or severely burnt.

Regarding the usefulness of investigating an older production 87V: if there is evidence of a design change that triggered the premature failure, that will at least help educate the used market to look for specific traits of older production runs. 

I've certainly cracked my share of small body PTCs testing these meters but the physically larger parts have held up.  It's really just the low end meters that I have seen use the smaller ones.  If you download that paper, do a search for MOV.  There is a section on them that will give some credence to what I plan to show in the next installment.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 23, 2018, 12:23:06 am
Joe, sorry this is out of line for your thread, but Pace Worldwide marketing is currently answering questions on that new low-cost station (the ADS200). They're close to you on the east coast.. maybe ask for a demo on the channel - just a thought..
https://www.eevblog.com/forum/manufacture/newest-pace-ads200-production-station (https://www.eevblog.com/forum/manufacture/newest-pace-ads200-production-station-(a-jbc-killer-at-) -(a-jbc-killer-at-$239)/

Back to regular programming folks! Sorry!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2018, 02:09:08 pm
The video for the remaining tests of the Fluke 87V are now on-line.   Enjoy. 

https://www.youtube.com/watch?v=dQPcAs0EEqY (https://www.youtube.com/watch?v=dQPcAs0EEqY)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 25, 2018, 12:25:45 am
The HIOKI handheld meter I previously tested uses a similar design.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 25, 2018, 12:35:43 am
The HIOKI handheld meter I previously tested uses a similar design.

Torture it on the rack!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 25, 2018, 02:55:52 am
The HIOKI handheld meter I previously tested uses a similar design.
Torture it on the rack!
Eventually, I may do that.   For now, am still focusing on that 87V.   I ordered up some new parts today to try some destructive testing with rather than using the Flukes.   

BTW, I forgot to mention than I had taken apart the 87V after the drop tests and the shield remained in place.  I think what is happening is the two clips that fit through the slots in the PCB need to be bent inward enough to get the shield to lock into place.  If you take one apart, they do seem a bit loose.  Looking at the old one that has a SN 10, it's the same way.   It was however installed flat when I first pulled it apart and again when I took it apart today. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 28, 2018, 02:03:16 am
I made a video where I applied 2KV to the current inputs of the 87V with it's fuses removed.  This is part of the 61010 standards.    There was smoke coming out out the meter. 

Attached is is picture showing the resistor used on the Rev 10 compared with the Rev 13 PCB.  If it looks like one resistor is much smaller than the other, that's because it is.  The layout was changed to support the larger resistors.   Now, this meter was certified up the ass by about every agency possible.   

The meter is rated for 1KV so again the standard calls for 2 times the highest rated voltage.   They are 1Meg resistors so that's 4 Watts for 1 minute that they need to handle.  The standard states, "During and after the test, no damage to the equipment shall occur."    If you have a the pre-2012 standards,  I would be very interested in knowing if and when this requirement changed.   

The larger resistors were warm enough to smoke.  What do you think these small ones will handle 4 Watts for a minute?     
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 28, 2018, 06:17:10 am
The larger resistors were warm enough to smoke.  What do you think these small ones will handle 4 Watts for a minute?   

It's not all about size.

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on March 28, 2018, 09:57:36 am
the old resistor is a carbon-core part that i have not seen for decades,
the new one is a flameproof type with a ceramic core to disipate heat and a metal film coating.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 28, 2018, 10:03:39 am
Are you sure it was the resistors smoking Joe and not the Mexican fuses about having to contribute to building the border wall ?  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 28, 2018, 02:29:19 pm
The video for the remaining tests of the Fluke 87V are now on-line.   Enjoy. 
Thanks Joe for the HVDC tests on the MOVs - although uneventful, they show how a good design can withstand some overvoltage (it was not the case of my old deceased meter).

The selector grinding really looks ugly and surprising to such an expensive Fluke. In my opinion the 87V still does not deserve any endurance prize when compared to some of its cheaper brethren.

the old resistor is a carbon-core part that i have not seen for decades,
the new one is a flameproof type with a ceramic core to disipate heat and a metal film coating.
Although the brown resistor looks old, it is a carbon molded resistor that is well into production. Tyco's CBT series (https://www.mouser.com/ds/2/418/NG_CS_1309350_PASSIVE_COMPONENT_0807-1235534.pdf) is quite similar in physical appearance.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 29, 2018, 01:14:26 am
The larger resistors were warm enough to smoke.  What do you think these small ones will handle 4 Watts for a minute?   
It's not all about size.

The door was left wide open on that one.  No takers.   :-DD

You can still buy carbon resistors.   I managed to find a 1M 1/2W CC and CF resistor in my stash.  I may power these up and see what happens.   I can't see testing the meter. 

The parts arrived today to make a mockup of the 87V's front end.


The video for the remaining tests of the Fluke 87V are now on-line.   Enjoy. 
Thanks Joe for the HVDC tests on the MOVs - although uneventful, they show how a good design can withstand some overvoltage (it was not the case of my old deceased meter).
The selector grinding really looks ugly and surprising to such an expensive Fluke. In my opinion the 87V still does not deserve any endurance prize when compared to some of its cheaper brethren.
Glad you found it helpful.  One thing to keep in mind, obviously the switch was in the off position.  The 87V does not switch in the low voltage clamp when it is off.  I doubt very much that the PTC, surge rated resistor and clamp would have survived with a 1.6KV DC applied.  If you crept up on it so the PTC had time to switch, I doubt it would like a over a KV across it.  And, no I will not offer to run that test for you on the 87V.   :-DD

I am surprised by the grinding as well.  I may life cycle the older one to see if it does any better.   Agree, for a higher cost Fluke, it just doesn't impress me. 
Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on March 30, 2018, 12:18:55 pm
Hey, Joe. Would you be interested in a functioning Fluke 87 series one, either as a spare or for testing?
It's fully functional, but with a caveat or two. I've been buying "broken" 87's on eBay and fixing them lately, so I have a surplus of series one meters.
I would be happy to ship this one to you at my expense.

This one I call the "Franken-Fluke" because it's been worked over. The LCD is darkened, I guess from sunlight exposure but works with no issues, has the green back-light.

In the course of troubleshooting I removed a surface mount transistor or dual diode (don't remember which) for testing and one of the foil runs got lifted but is still there under the device and not causing problems, but if you were to "torture test" the unit and go to replace the device it might cause you a problem.

The input jack ass'y was replaced with one from an 83, the original was bad.

The "top shield" with the little clippy things is damaged and doesn't properly secure the LCD elastomers to the board.
This is not a problem in normal use because when the case is screwed together, tension is sufficient, and the digits read fine. This was a happy co-incidence because the LCD window in the top case has been replaced, but apparently was a little thicker than the original, so it puts a little tension on the LCD mask as the case screws are tightened.

Rather than have to explain all this in an eBay listing, I think I'd just as soon give it to you. Interested?

Reply here or PM with a shipping address for you and I'll send it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2018, 02:08:58 pm
Thanks for the offer but I really don't have a use for it.   I would guess there are people on this site that would really appreciate having some of the parts off of it or even the whole meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: mzacharias on March 30, 2018, 05:45:17 pm
OK.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2018, 04:47:17 am
I am trying to determine why the older Fluke 87V failed at such a low voltage.  With most meters it's pretty easy to see why they fail.  In many cases where meters were damaged at lower levels, I have shown how some like the 121GW, UT181A, UT61E and even the cheap ZT102 could be improved.  We even tackled a cheap analog meter for the fun of it.    In the case of the older Fluke 87V, it has not been so simple.  I did record all of the testing and plan to post it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2018, 09:42:30 pm
Running tests on the older Fluke 87V. 

https://youtu.be/GhslaLKOpKE
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on April 02, 2018, 07:58:24 pm
Very interesting outcome.  Makes it clear that it’s not a problem with the fundamental design. I think the previous failure was just a fluke.

I’ll be here all night.   Try the veal.



Sent from my iPhone using Tapatalk
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 02, 2018, 10:25:01 pm
Very interesting outcome.  Makes it clear that it’s not a problem with the fundamental design. I think the previous failure was just a fluke.
I no longer believe this was a design problem or a component problem.  I also don't believe it was a quality problem on Fluke's part.  This meter was fairly old and I wonder if something conductive had come off at some point.  Even if this were the case, I don't see where it would have been able to arc and cause this sort of damage.   I monitor pretty much each transient during the tests to see if something starts to breakdown.  Even if the transient generator has some major fault and I missed seeing it with the scope,  it's not capable of putting out more than what that last test I ran.   
Title: Re: Handheld meter electrical robustness testing.
Post by: ChrisLX200 on April 02, 2018, 11:53:25 pm
The fact it was an old meter with no dependable record of its history leaves open the possibility those components had already been stressed to the point of failing prior to the test being run. I suspect the result using the repaired meter (with new diodes) is more typical of what you may expect.

The fascinating thing to me is the apparent ease with which you manage to repair a blown up meter :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 03, 2018, 12:26:51 am
The fact it was an old meter with no dependable record of its history leaves open the possibility those components had already been stressed to the point of failing prior to the test being run. I suspect the result using the repaired meter (with new diodes) is more typical of what you may expect.

The fascinating thing to me is the apparent ease with which you manage to repair a blown up meter :)
You make a very good point and while I have had several people offer to provide me with older meters or request me to run them, I typically decline mainly for that reason.  In this case, I personally know the person who bought the meter brand new and know they do not work on line voltages, normally.    It was a gamble to run it and it seems in this case, it corrupted the data.  Like you, I do not believe a new 87V would ever fail like this after seeing how the meter is designed and with all of the tests I ran.   

So yes, I am fully willing to eat crow over this particular 87V now.  As far as electrical robustness, I now have absolutely nothing bad to say about any of the Fluke meters I have looked at.  From a mechanical standpoint, I don't like the 87V switch wear but it was making good contact and still better than most of the meters I have looked at.   

They are old designs for the most part and they don't really make a meter that I like or would use.  Maybe one day they will bring back a modern version of the 189.  That IMO, was just a nice clean design.   Not a lot of fluff and has all the basic features.     
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 03, 2018, 02:09:20 am
Today, after almost three years, we set a new milestone with this thread.  The admins were called in to censor a few posts.  To try and avoid future problems, I have updated the first post to include some basic rules and guidelines to follow if you plan to post on my YT channel.
Title: Re: Handheld meter electrical robustness testing.
Post by: ChrisLX200 on April 03, 2018, 05:54:36 am
...
 From a mechanical standpoint, I don't like the 87V switch wear but it was making good contact and still better than most of the meters I have looked at.   
...

As an 87V owner I was also surprised and concerned by the awful rough movement developing in the rotary switch, although it's difficult to make sense of what is happening (how it 'feels') based on the sound as reproduced on the video. I gave it some thought and suspect it is the result of two things: the spring contacts being slightly 'loose' in their housing (by 'loose' I mean the tension holding it in place may be lower than optimal), and secondly the fact you use a constant speed when turning the switch on your jig. I would suggest the latter, in combination with the less than secure spring retention, allowed a sympathetic chattering to develop.

Chattering will be dependant on a number of factors: the amount of friction between spring contact face with plated track, the surface area of the contact face (which will increase as small flats are worn into them as they bed in), and the base spring tension pressing the two components together (oh, and speed!). If the spring retention mechanism allows enough flexibility such that friction overcomes its ability to slide smoothly (and thus sticks for a fraction of a second) then you will get sympathetic chattering, however this will be exacerbated by using a constant speed allowing the pattern to be imprinted into the track itself. Once established there will be positive feedback and things will only get worse as the procedure continues. Note that a lubricated track may have reduced the friction to the point where sticking would not occur - but all the other factors need to be in place before this would become a critical factor.

(There are similarities with using a parting tool in the lathe, the factors that cause chattering are similar, and if nothing can be done about the stiffness of tool mounting or play in headstock bearings then adding lubrication and/or adjusting cutting speed often resolves the problem)

Such perfectly constant speed provided by your test jig is not something that is seen in real life when simply turning the switch manually, so the chances of developing such a pattern of chattering will therefore be reduced. I do understand your idea about reducing the possibility of heat being generated due to  turning the switch too rapidly but I also think you should vary the speed too.

It may be too late for that test example now (given the state of the tracks), but perhaps re-tensioning the spring contacts so they are held in place more firmly,  a few seconds on a buffing wheel to round off any sharp flats formed on the spring contact faces, and perhaps a little lubrication would restore proper function.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 03, 2018, 04:23:51 pm
Today, after almost three years, we set a new milestone with this thread.  The admins were called in to censor a few posts.  To try and avoid future problems, I have updated the first post to include some basic rules and guidelines to follow if you plan to post on my YT channel.
Wow, that is quite odd. The discussion was quite civil in my opinion. Perhaps there is no desire to criss cross feuds happening in another platform. Oh well... Back to your normal programming I guess.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 03, 2018, 04:49:57 pm
Today, after almost three years, we set a new milestone with this thread.  The admins were called in to censor a few posts.  To try and avoid future problems, I have updated the first post to include some basic rules and guidelines to follow if you plan to post on my YT channel.
Wow, that is quite odd. The discussion was quite civil in my opinion. Perhaps there is no desire to criss cross feuds happening in another platform. Oh well... Back to your normal programming I guess.
I was surprised myself and did not think I posted anything that would warrant having the posts pulled.  I didn't even consider it a feud of any sort.  I suspect they just did not like being called out for advertising on my channel and posting misinformation.   Read the rules and if you can't follow them, there is no need to tell me you are unsubscribing over them.  I won't care.  Just unsubscribe and move on.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 03, 2018, 05:00:03 pm
...
 From a mechanical standpoint, I don't like the 87V switch wear but it was making good contact and still better than most of the meters I have looked at.   
...

As an 87V owner I was also surprised and concerned by the awful rough movement developing in the rotary switch, although it's difficult to make sense of what is happening (how it 'feels') based on the sound as reproduced on the video. I gave it some thought and suspect it is the result of two things: the spring contacts being slightly 'loose' in their housing (by 'loose' I mean the tension holding it in place may be lower than optimal), and secondly the fact you use a constant speed when turning the switch on your jig. I would suggest the latter, in combination with the less than secure spring retention, allowed a sympathetic chattering to develop.

Chattering will be dependant on a number of factors: the amount of friction between spring contact face with plated track, the surface area of the contact face (which will increase as small flats are worn into them as they bed in), and the base spring tension pressing the two components together (oh, and speed!). If the spring retention mechanism allows enough flexibility such that friction overcomes its ability to slide smoothly (and thus sticks for a fraction of a second) then you will get sympathetic chattering, however this will be exacerbated by using a constant speed allowing the pattern to be imprinted into the track itself. Once established there will be positive feedback and things will only get worse as the procedure continues. Note that a lubricated track may have reduced the friction to the point where sticking would not occur - but all the other factors need to be in place before this would become a critical factor.

(There are similarities with using a parting tool in the lathe, the factors that cause chattering are similar, and if nothing can be done about the stiffness of tool mounting or play in headstock bearings then adding lubrication and/or adjusting cutting speed often resolves the problem)

Such perfectly constant speed provided by your test jig is not something that is seen in real life when simply turning the switch manually, so the chances of developing such a pattern of chattering will therefore be reduced. I do understand your idea about reducing the possibility of heat being generated due to  turning the switch too rapidly but I also think you should vary the speed too.

It may be too late for that test example now (given the state of the tracks), but perhaps re-tensioning the spring contacts so they are held in place more firmly,  a few seconds on a buffing wheel to round off any sharp flats formed on the spring contact faces, and perhaps a little lubrication would restore proper function.


Fact
 noun
1. something that actually exists; reality; truth:
Your fears have no basis in fact.
2. something known to exist or to have happened:
Space travel is now a fact.
3. a truth known by actual experience or observation; something known to be true:
Scientists gather facts about plant growth.
...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 03, 2018, 05:24:31 pm
It might be worth investigating where the dial noise comes from.

eg. Put some very viscous grease in the white switch dial thing to dampen any movement of the contact springs where they touch it.

This would let you know if the noise comes from PCB scraping or rattling of the springs in the housing.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 04, 2018, 12:47:57 am
It might be worth investigating where the dial noise comes from.

eg. Put some very viscous grease in the white switch dial thing to dampen any movement of the contact springs where they touch it.

This would let you know if the noise comes from PCB scraping or rattling of the springs in the housing.

If you have not taken the time to watch the video, I added a couple of pictures that may interest you.  It's really up to Fluke to determine if they consider it an issue and how they want to address it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 15, 2018, 06:36:18 pm
After doing some maintenance on the generators,  played with a few light bulbs for fun.  Funny to see how the voltage levels that damaged so many cheap meters effects a simple light bulb.   

https://youtu.be/aaZxWMgOz70
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 15, 2018, 11:39:01 pm
Viewer posted:
Quote
chrimony
4 hours ago
@6:10 Surprised to see the plasma outside the bulb.?

I responded that I suspect this was from the arc that occurred at the base of the bulb and those gases escaping out of the socket.  With a 1ms frame rate, the camera is just not fast enough to tell the whole picture.

Here are the 5ms of footage.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 05, 2018, 01:13:29 am
Getting ready to look at another meter.  I've been busy repairing an old scope that a friend of mine gave me that happens to be just like one I had given away a few years ago.   I have finished it up but have some cleanup to do along with some other spring time work that needs to get done but I hope to get started this weekend.

Again, I want to than those of you who have offered to pitch in and buy me this meter to run, or out right offered to pay for it.  I appreciate the gesture.  Maybe one day I will open some sort of account to allow people to donate.   For now, consider the small bit of data I supply as my way of giving back to the technical community.

Yes, the meter is here..  It looks scared.. 
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 05, 2018, 02:49:10 am
Getting ready to look at another meter.  I've been busy repairing an old scope that a friend of mine gave me that happens to be just like one I had given away a few years ago.   I have finished it up but have some cleanup to do along with some other spring time work that needs to get done but I hope to get started this weekend.

Again, I want to than those of you who have offered to pitch in and buy me this meter to run, or out right offered to pay for it.  I appreciate the gesture.  Maybe one day I will open some sort of account to allow people to donate.   For now, consider the small bit of data I supply as my way of giving back to the technical community.

Yes, the meter is here..  It looks scared..
That's the same one my sparky mate uses for pretty much everything domestic and industrial.
Will be very interested to see how it fares.  :)
TIA Joe.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 05, 2018, 05:07:41 pm
Poor Flukes.  Like any other meter, they always have to earn my respect.   
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 05, 2018, 08:24:32 pm
Looks like it tried to escape you, LOCKED in the Panavise now! :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 06, 2018, 05:15:44 pm
There may be a part 2 to talk about the sensor's design.   Enjoy.

https://youtu.be/k8hhtTtWfVc
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on May 06, 2018, 11:58:59 pm
Break down & repair, very detailed as usual. Great job Joe!
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 07, 2018, 01:20:09 am
There may be a part 2 to talk about the sensor's design.   Enjoy.

That was remarkably accurate. It mostly got the voltage correct to ±1 volt with no direct contact. I'm impressed.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 07, 2018, 02:56:23 am
Even with me being fairly insulated I was amazed how well it works.   

I soldered some test points the to the board and started to poke around it.  They seem to use a 2.4KHz sinewave for their reference.  I have not done a lot of tests but it appears to always be running (while in the non-contact mode).   This make some sense as they need to actively measure the capacitance.   The capacitance from a wire to the sensor is in the 10s of pf.  Looks like maybe two plates, one with a lower capacitance.   

They must have to work with uninsulated wires as the area near the jaw is very thick.  Moving a wire inside the saw area with the cover removed, it is really sensitive.   

With the low freq. reference and working in the few megs of coupling, it may explain why the unit has troubles with high frequency signals.  I wonder if they would be better off making the final measurement with the reference disabled.  Talking out of my ass.  I really have no idea how it even works yet.... 


 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 09, 2018, 04:26:41 am
Running the Fluke T6 on the half cycle line simulator.   

https://www.youtube.com/watch?v=s6C6KsypBAc&t=2s (https://www.youtube.com/watch?v=s6C6KsypBAc&t=2s)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 10, 2018, 02:44:42 am
With the low freq. reference and working in the few megs of coupling, it may explain why the unit has troubles with high frequency signals.  I wonder if they would be better off making the final measurement with the reference disabled.  Talking out of my ass.  I really have no idea how it even works yet....
As this is predominantly an electricians DMM I wonder how the non-contact feature work with motor speed control inverters ?
How does it sense approximate voltages and currents by comparison to a scope and current probe ?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 10, 2018, 11:04:56 am
As this is predominantly an electricians DMM I wonder how the non-contact feature work with motor speed control inverters ?
How does it sense approximate voltages and currents by comparison to a scope and current probe ?
I don't have any motors like this.   I could try it on the mains panel but the loads in the house are going to be fairly clean.

I've thought about taking one to a few places to try it just, for my own curiosity.

Using a scope would vary on the setup.   Probes could be picked to give a nice dynamic range.  You are locked in with this Fluke clamp.  There is no range selection.   With the scope, you may be able to over sample.  If you wanted, you may be able to also compensate for other limitations with a scope to get even better results.   Then again, I would assume if you are using this Fluke, you are an electrician and I doubt they would have the same requirements.   Hard to imaging an electrician taking a scope and current probes into the field.    I am not an electrician but if I have to go into the field I will take that HIOKI I have shown.  Two different tools with different price tags...

Using Labview with my old scope along with the breakout box I showed in the Fluke video.
https://youtu.be/04I7nHA_HxM?list=PLZSS2ajxhiQBcHhIaGpmm9GyZQfrCzqkv

   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 11, 2018, 01:12:42 am
I tried a few different things with the meter today.   First test was on about a 5ish HP 220V 3P motor.  No problems.   I then tried it on a single phase 220V, phase controlled 30A load.  Again, no problems while controlling the current.   I then tried it with a small 220V 1.5KW 3 phase Omron controller and saw no problems.    In all cases I was trying it with and without grounding and it seems to do fairly good with my work boots on while standing on concrete.   

The biggest complaint I would have is having to bend the wires to get them into the jaw to make the measurements.  The systems I was working with had wires that liked to move. 

I showed a few people who were also impressed with how well it could read the non contact voltage.  I did get a comment once about working with my one hand on the equipment while probing around.  Good to know people still worry about me.

Again, I am not an electrician or work in a place where I would need to measure the AC mains but I could see something like this being handy under the right circumstances.   

***

Just to add, I forgot to mention that the Omron controller uses PWM and was surprised the T6 could read it.  I am not sure why it had so much trouble with some of the other waveforms I was testing with.    Attached is looking at one phase from this controller.



Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 11, 2018, 05:07:27 am

***

Just to add, I forgot to mention that the Omron controller uses PWM and was surprised the T6 could read it.  I am not sure why it had so much trouble with some of the other waveforms I was testing with.    Attached is looking at one phase from this controller.
Thanks Joe, exactly what I was wondering about.
Indeed measurement of modern systems control can be challenging and it's good to know the T6 can deliver at least the basics in this regard.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 12, 2018, 01:58:18 am
To me, it makes no sense that the T6 could handle the PWM from the Omron VFD and have problems with some of the waveforms I used with the ARB.   A few people had pointed out how when I started to move the wire with my finger that the T6 started to read the voltage.  Maybe there is something else going on there.   


Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 12, 2018, 02:40:37 am
To me, it makes no sense that the T6 could handle the PWM from the Omron VFD and have problems with some of the waveforms I used with the ARB.   A few people had pointed out how when I started to move the wire with my finger that the T6 started to read the voltage.  Maybe there is something else going on there.
Surely it's just sensitivity related....real power levels vs little signal level stuff.
It is an electricians DMM not an electronic engineers meter, right ?

Horses for courses.  :)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 12, 2018, 03:44:39 am
I am not sure what we would call sensitivity.  The T6 seems fairly sensitive to pure sinewaves at voltages ranging from 16 up to 440ish.   20Hz it was rolling off a bit but 50 to 400Hz seems to have little to no effect on how it detected the voltage.    Everything I tested it with at home was at less than an amp.   So I agree, it is little signal stuff.   

But a simple sinewave with a spike at the zero cross, which is a standard IEC waveform, that it has a problem with.  Even a 60Hz square wave causes problems at higher voltages.   Sure there is no load when I ran these tests and I am really only concerned with the non-contact voltage detection.   What I don't understand is why it has no problem with that Omron controller.  It's using a 15KHz carrier PWM signal.  I tried it at 50 to 60Hz. It's fairly square.  There is no load as well.  Just a wire hanging off the controller.    I was VERY surprised that it worked at all.     

The manual mentions both the safety and EMC standards.  I would have thought they would have ran all the basic harmonic tests.   

I am thinking to write some sort of  program to automate a much larger test where I very several parameters and try to get a better idea what is going on.   
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 12, 2018, 03:54:41 am
Some reviewers have said "this thing sucks, it doesn't work at all". You found that it sometimes works, but sometimes not.

I'd guess there is some factor "X" at play regarding the conditions in which it is used, maybe alignment of the wire under test or something?

A puzzle for sure. On the other hand, if a test instrument is not reliable, then how can it be trusted?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 12, 2018, 04:54:37 am
Some reviewers have said "this thing sucks, it doesn't work at all". You found that it sometimes works, but sometimes not.

I'd guess there is some factor "X" at play regarding the conditions in which it is used, maybe alignment of the wire under test or something?

A puzzle for sure. On the other hand, if a test instrument is not reliable, then how can it be trusted?

We have seen other instruments with design problems that were not discovered for several years, yet people trusted the results.   

Watching the video review, we see a Klein Tools, PN#  69409 splitter being used to attempt to make the measurement.  Looking at the quick reference, the first thing it the overview,  they talk about 1 wire only and the wire must contact the bottom of the fork.   There are also pictures that make it easy to understand.   Of course, in this case an understanding of the splitter was required as well.    We really have no way of knowing the specifics of people providing feedback.  The best I can offer is to just show you the tests I have ran. 
 
When I took the T6 with me for the day, I didn't have any problems if I could get to the wire I wanted to measure.   However, all of those signals I would say were common and clean.   

If I were trying to make these sort of measurements often, as say some sort of process control,  I can see it saving time and being safer to use.   Would I use it to make basic voltage measurements and trust the results, based on my experience with it, I would say in many cases, yes.   

When I run my own tests, I am looking for problems.  This is why I use an arb rather than a wall socket to test the meters.  Obviously, I discovered cases where it can't detect the voltage depending on the shape of the signal.   This is really what interests me. 
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 12, 2018, 05:27:12 am
First one need understand the MO of an electrician when he needs to pull out a meter. Typically not everyday.

What the measurement requirement is determines whether they reach for Duspol or a DMM.
Is voltage present, is it real or phantom ? (LowZ test)

Controls systems: 12, 24 or 48V AC or DC and not much else.
Power systems (universally) 110/120, 230/240, 400/440 VAC. 1% accuracy is all that's generally required.
Current.....mainly to fault find the reason why breakers are tripping, checking AC motors are running within spec and checking circuit's aren't overloaded.
Continuity, checking HRC fuses and similar menial tasks.

Not exactly demanding work for a DMM but it needs be reliable, repeatable, trustworthy.....and safe.


So where might a T6 shine ?
My buddy was called into an industrial installation where a big AC motor kept tripping its breaker. As breakers don't like ongoing tripping events due to bi-metal degrading that was the first thing replaced......still tripped, motor rated breaker and all. Test phase current draw and how it compared to motor label spec.....well over.
Open frame motor and in a dusty environment.....10 minutes with high pressure air and tripping problem fixed.

Yep and you could have diagnosed it with any cheap clamp meter too but if you turn up on a job with a Fluke, those in the know immediately respect your ability to know what you're about.

The T6 is not an EE's meter, period.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 12, 2018, 12:26:08 pm
Hard for me to say what the use cases would be for this meter.  I wouldn't say a EE would never have a use for the T6 but it is not a tool I would ever use on a bench.  I personally could see non-electricians using the T6 in certain cases.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 12, 2018, 06:56:46 pm
Hard for me to say what the use cases would be for this meter.  I wouldn't say a EE would never have a use for the T6 but it is not a tool I would ever use on a bench.  I personally could see non-electricians using the T6 in certain cases.

Everybody's freaking out about how if you'll die if you touch the metal stuff but it's obvious Fluke would have thought of that on day zero.

The main problem I see with it is that you need a lot of space around a wire to be able to take a reading. That really limits where you can actually use it IMHO.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 12, 2018, 09:03:39 pm
Hard for me to say what the use cases would be for this meter.  I wouldn't say a EE would never have a use for the T6 but it is not a tool I would ever use on a bench.  I personally could see non-electricians using the T6 in certain cases.
Everybody's freaking out about how if you'll die if you touch the metal stuff but it's obvious Fluke would have thought of that on day zero.

Are they still?

Quote
The main problem I see with it is that you need a lot of space around a wire to be able to take a reading. That really limits where you can actually use it IMHO.

Have you tried to use it?   

I'm setting up a more comprehensive waveform test.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 13, 2018, 03:56:23 am
Checking the T6 with various waveforms.   IMO, this is a much bigger problem than the leakage current through the button.  Looks like they need to invest in something like this:
http://www.programmablepower.com/test-compliance/index.htm (http://www.programmablepower.com/test-compliance/index.htm)


https://youtu.be/JeX87PklmEU (https://youtu.be/JeX87PklmEU)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 18, 2018, 01:00:02 am
Following Dave's technique, Voltlog tried using an insulation tester on a few handheld meters.   He quickly discovered that while in the resistance mode, the loading was just too much and he could only get a few volts. 

I wonder what would happen if we put 1KV DC across a cheap meter when it was in resistance mode.  It's not something I have ever tried.   

https://www.youtube.com/watch?v=pnv5qJoWIak&t=1036s (https://www.youtube.com/watch?v=pnv5qJoWIak&t=1036s)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 20, 2018, 12:33:58 am
In order to repeat VoltLog's test the Joe Smith way, we can't use a handheld insulation tester as a source.   

Note, if your have a 1KV supply and your using your meter to measure the current from it and the 440mA fuse blows, the first thing you need to be aware of is you now have 1KV across your meter's current inputs.   And you guys wonder why I test this these things.     The second thing to note is working with 1KV at 440mA  could end your life.  A GFCI will trip in well under 10mA in 100ms or so.    Here we are playing with DC. 
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on May 20, 2018, 01:59:29 am
This is when you start to wish meters didn't use $10 fuses...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 20, 2018, 06:00:05 am
The fuse cost more than the meter that caused it to blow.    Not sure how a half amp 240VAC glass fuse would like the 1KV DC.  Also not sure how many low end meters would survive with 1KV across their current inputs. 

https://youtu.be/HkdJ66vetWg

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2018, 09:50:18 pm
Just a quick update on the T6.   I received this comment a while back:

Quote
The other problem with the non-contact voltage measurement of the T6, is that it is referencing to earth. When ever I am fault finding in a panel, I am testing phase to phase or phase to neutral as that is the working circuit. Testing phase to earth is poor measuring technique, and is predominantly done when testing of absence of voltage, which the T6 is unsuitable for.

It made no sense to me that the meter would not work using the non-contact mode when reference to something other than the earth ground.   So I tried it on a few 3P circuits using a one phase for a reference and the non-contact on the others and as expected, saw no problem at all using it this way.   Obviously you would have to have failed your studies if you were to touch the button and grab a live phase with your other hand.   I am using the black reference probe when doing these tests.

I also had access to another Mitsubishi VFD that I tried it on.   The VFD was running a motor.   No matter what I tried, I could not get the T6 to read the voltage.  This controller was running with a carrier at 5KHz.  The VFD was reprogrammed to 15KHz and the T6 worked fine.   We tried a few other lower frequencies and was unable to get the T6 to read. 

All of the testing I had done up till now with VFDs was at higher frequencies.  Leakage current may be a problem and I would assume many controllers will run low carriers.  My guess is the T6's non-contact feature will have problems with this. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2018, 08:27:53 pm
Effects of 1KV on PCB rotary switch.

https://youtu.be/6j8i3LfKm5A
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 09, 2018, 09:08:36 pm
That was very effective, Joe. I hadn't thought about the case of the switch being rotated while overloaded. Dragging an arc is certainly plausible and pretty spectacular.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on June 09, 2018, 09:30:51 pm
Interesting. At 1000 V every mA is 1 W of power dissipation. It doesn't take many watts concentrated in a small area to cause heat damage. To make a multimeter completely idiot-proof and still work effectively at reasonable cost must be quite a challenge. One possibility might be some kind of mechanical interlock where you have to operate a separate off/disconnect switch before you can turn the dial. But then even the disconnect contacts would be subject to arcing...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2018, 10:15:48 pm
Of course the 121GW is only rated to 600V. 

https://youtu.be/3oGEKVp0bso
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 09, 2018, 10:26:17 pm
That was very effective, Joe. I hadn't thought about the case of the switch being rotated while overloaded. Dragging an arc is certainly plausible and pretty spectacular.

We have no way of knowing what happened with Kean's meter but I would not rule out high current / high voltage.   If I personally had damaged the 121GW like this, I would own it.  I may even try to replicate it for a video and then try to improve the design.

Interesting. At 1000 V every mA is 1 W of power dissipation. It doesn't take many watts concentrated in a small area to cause heat damage. To make a multimeter completely idiot-proof and still work effectively at reasonable cost must be quite a challenge. One possibility might be some kind of mechanical interlock where you have to operate a separate off/disconnect switch before you can turn the dial. But then even the disconnect contacts would be subject to arcing...

I'm not sure what could be done to prevent something like this.  Normally at home if I am working with KV and higher the currents are sub mA.   I have been testing all the meters with the full rectified 220V AC and limit the current to something around 40mA.   I've had a few meters get damaged during this test.   At a KV it's going to be even more difficult to try and save the PCB.  Something to think about.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on June 10, 2018, 01:23:16 am
At least the cheap Harbor Freight meters have appropriate warnings in the instructions.  They clearly say you should wear gloves, eye protection and full PPE before using the meter...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 10, 2018, 02:45:28 pm
The spreadsheet now contains the test results for the latest revision of the Fluke 87V along with the repaired revision 10 unit. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 11, 2018, 12:36:41 am
After watching Dave's latest videos where he exposes the 121GW to 1100V DC to show that the contacts would not arc over at those levels, I decided to repeat the same test with the free DT830 meter from Harbor Freight.   The new ones are only rated to 250VDC.  Will it survive with 4 X it's rated voltage??  Seems like a tall order for a free meter....

No attenuators were used in the making of this video

https://youtu.be/mjTzMR-7ilo
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 11, 2018, 04:20:39 am
Hmm, I wonder if something happened with one or more of the free DMMs that triggered the relabeling of the uppermost ranges.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 11, 2018, 06:52:52 am
The new ones are only rated to 250VDC.

Interesting.

The $20 Zotech/ANENG style meters have just dropped down a whole CAT level, now these are only rated labelled to 250V. I wonder if somebody's getting tough on them.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 11, 2018, 07:04:00 am
Sounds like it. 'Bout time. ^-^
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on June 11, 2018, 09:49:45 am
one poss fix to arc-over is if the switch is covered in some type of insulating slime or grease that has a consistancy like gell.
i have seen something like this in some old industrial switches for starting large engines - before they started using relays.
Title: Re: Handheld meter electrical robustness testing.
Post by: Kean on June 11, 2018, 01:06:00 pm
We have no way of knowing what happened with Kean's meter but I would not rule out high current / high voltage.   If I personally had damaged the 121GW like this, I would own it.  I may even try to replicate it for a video and then try to improve the design.
Yeah, I'm happy to "own it".  :-DD

As I've mentioned in the YT comments and 121GW forum post, it looks like I screwed up and used the 121GW when I shouldn't have - measuring the HV output of an ultrasonic transducer driver.  Roughly 1200V at 25-28kHz, at potentially 100W!

I don't remember doing this, but it really seems like I must have.   :palm:  And I very likely didn't use this meter again till I went to measure that flakey DC/DC converter a week or so later and saw 166V, then OFL, instead of 5V.  It measured more like 3.5V on an EEVblog/Brymen 235 meter, and that was fixed with some extra input capacitance.

I tried to reproduce the damaging arc on a test PCB - an SMD breakout with approx the same 1mm trace gap.  I was set up to take video and everything, but it just wouldn't arc over by itself, and I wasn't game to manually start the arc like Joe did.  Most likely would have killed my driver board.

And I'm also happy to say that the meter survived after cleanup of the PCB.  Even the protection diodes that are in the path seem to measure fine (forward voltage and leakage).   :-+

Thanks again Joe for the excellent series of testing videos you've been producing.   :-+ :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on June 11, 2018, 05:51:40 pm
Joe, thanks for the HF testing; I have done this myself several years ago without issues, but I had them thoroughly disassembled and scrubbed for subpar production quality - i.e., loose springs, screws or solder blobs.

My oldest M830B meter is quite well built and this thread (https://www.eevblog.com/forum/reviews/harbor-freight-cen-tech-90899-small-teardown/) shows many internal photographs of "830" models over the years, including the latest derating on the maximum voltage specs.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on June 11, 2018, 07:28:58 pm
Thanks for the update, Kean. Mystery solved.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2018, 12:07:09 pm
CAT ratings while working in the home.

It was late and while we were watching a movie, a storm kicked up.   Part way through the movie we heard a big boom.  It's near the 4th so there are a lot of fireworks but this was much louder and the outside was a large flash.  I made my wife stay inside while I checked to see if the house had been hit.   No signs of a fire.   We both went outside to investigate and the neighbors were out as well to check.   It seems a bolt hit a tree in our yard and traveled to the roots.  The roots appear to have made contact with the phone can coax cable.   It blew the cover off the phone box but there was no signs of damage.     The phone cable is not in use.    The coax feds the modem only.   The modem was dead.  The modem contains a GDT which had signs of a major strike.  The area around the transformer (data) had blown a few components blown off the PCB.     The VOIP box that was connected to the Ethernet was also damaged.  Both wall power supplies for these devices are still fine.  These were running off a UPS.   

It also made it's way into the AC mains and we lost a few devices.  People have talked about the CAT ratings in a home and how the energy is limited.     The part about this I like is that we are no longer limited by fuses on a pole or some upstream transformer and cable losses.    All those CAT ratings go out the window. 

The garage door opener has two half inch sparkgaps made into the PCB with an isolation slit.  The arc jumped this and vaporized several traces.  There's a TVS downstream, that was gone.   

One of the lightbulbs that was lost looks to have a fair amount of damage to the base.  It's a CFL.  Perhaps they are more mechanically robust than an incandescent bulb.

I've looked at a lot of meters that I wouldn't want to be using that day in a CAT II environment....     

Furthest sod was about 20' from the base of the tree.    For those that have written me suggesting that my little transients are too harsh and how things like this can't happen,  I stand by what I have said all along.  My little transients are nothing.   
Title: Re: Handheld meter electrical robustness testing.
Post by: saturation on July 03, 2018, 02:29:49 pm
Joe do you have any surge protectors plugged into these circuits at the time of the strike?  Even if working some of them could be toast inside, if so photos please.  Folks capable of making informed engineer level reports about strikes are not common so your opinion and photos would be a plus.

CAT ratings while working in the home...
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 03, 2018, 02:50:59 pm
Joe, sorry for the losses around your house. Fortunately no one was hurt apart from the tree. I suspect you will have your hands full reporting the damages with lots of photographs and short videos and reworking a few of the least damaged ones - if not for your channel perhaps to the insurance company (is that applicable?). 

I would keep a close track on how the tree goes from now on; it may have caused some severe damage to its internal systems and it may be partially or totally dead.

Taking into consideration the damage done, it is a coin toss on how any CAT rated meter would help the operator survive; however, the chances would be obviously much higher with a truly certified one.

In a distant past (in the ages where 14.4kbps POTS modems were the new thing), the apartment building right beside us was hit by lightning, which ruined many of the appliances and electronics of that building. I was working on the computer at the time and it simply rebooted with the transient - fortunately I was not connected to the BBS and we used to leave the modem disconnected via an ancient dual pole 20A disconnect switch similar to this one.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=468119)

Despite our pride in our disconnect switch, at about the same time a friend of mine experienced a discharge that went through his house (metal piping) and destroyed the regular appliances/electronics and even destroyed some of the masonry walls (houses in Brasil are brick-and-mortar). This gave me the realization that no matter what we use to protect the appliances, when a lightning strikes we should forget them and need to be thankful that we are simply alive.  :-BROKE

 
Title: Re: Handheld meter electrical robustness testing.
Post by: BillB on July 03, 2018, 03:55:00 pm
Joe do you have any surge protectors plugged into these circuits at the time of the strike?  Even if working some of them could be toast inside, if so photos please.  Folks capable of making informed engineer level reports about strikes are not common so your opinion and photos would be a plus.

+1

Sorry about the damage, and glad nobody was hurt.  Pictures of lightning destroyed stuff are always welcomed!
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 03, 2018, 08:19:27 pm
Wow, Joe. That's quite the fallout from a strike. I haven't experienced a direct hit like that. It certainly is a wakeup call. Out of habit, I generally turn off power strips when leaving for an extended period, but with a lightning strike, I suppose that doesn't really help. It sounds like the surge would jump right past the switch.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on July 03, 2018, 08:21:32 pm
check everything you have with an ethernet port to see if they still work.
unfortunatly i have seen a lot of dead network interface chips caused by lightning - the emp gets into the transformer and kills the controller even if the port is not connected.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 03, 2018, 08:25:28 pm
Woah :o
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2018, 11:02:14 pm
Well, it's starting to look bad.  I had my old HP spectrum analyzer apart for service and went to set it back up only to discover that I have some major problems with the test equipment.   Most of this is very old and for insurance, it's a bit of a question what to even do about it.  As it stands, I can't even access the level of damage because the equipment I need to use is dead. 

Everything was off at the equipment as well as the bus strips were all off.   

On the Ethernet side of things, the modem goes to the VOIP.  The only other thing I normally would have tied into it is a laptop.  With Windows 10 phoning home non-stop and disrupting anything I do with the laptop,  I had it unplugged and it survived! That's right, Windows 10's performance is so bad it saved that hardware.   :-DD :-DD 

The modem talks wireless to another router that I have all my Windows 10 blocking on.  This then runs all of the test equipment and PCs.   

I recently posted about changing one of my UPSs to use super caps rather than lead acid.   This UPS has a fair bit of protection.  I had just put it on-line a few days prior.  It was running at the time of the strike and continues to run.  It appears to have no signs of any damage.  There is no damage to anything that was running from it.   

The test equipment is my biggest concern at the moment.   Several years to accumulate and repair.  At least my old HP 3589A is in perfect working order again so take that mother nature!  :box:
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on July 03, 2018, 11:19:46 pm
Well, it's starting to look bad.  I had my old HP spectrum analyzer apart for service and went to set it back up only to discover that I have some major problems with the test equipment.   Most of this is very old and for insurance, it's a bit of a question what to even do about it.  As it stands, I can't even access the level of damage because the equipment I need to use is dead.

Well, shit, that's bad  :(
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on July 03, 2018, 11:30:01 pm
Sorry to hear that Joe...

With a hit that close, at least some damage will come from induced (EMP style) pulse, in addition to any conducted overvoltage...

Hope there is not much more damage, and good that nobody got hurt.

Regards,

Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 03, 2018, 11:38:08 pm
Well, it's starting to look bad.  I had my old HP spectrum analyzer apart for service and went to set it back up only to discover that I have some major problems with the test equipment.   Most of this is very old and for insurance, it's a bit of a question what to even do about it.  As it stands, I can't even access the level of damage because the equipment I need to use is dead.

Well, shit, that's bad  :(

It's not that bad.  The house was not damaged and no one was injured.   And the HP3589A was being serviced at the time and in parts.  No where near an outlet. Also on the plus side, my trusty PACE soldering iron survived. 

Looking at my two Ethernet GPIB controllers, they were built roughly the same time.  One has a heat shrink around what appears to be a couple of large MOVs.  The other does not.  One has a plastic sheet isolating the power supply from the digital section, the other does not.   Both were turned off, both no longer pass the basic diagnostics.  Expecting to see some chips blown apart, there really is nothing exciting.  Nothing even running all that hot.  Custom ASICs, so not going to be able to do anything with them.   Time to drag out an old GPIB controller...
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 03, 2018, 11:48:17 pm
..Also on the plus side, my trusty PACE soldering iron survived.
Maybe Aaron could send out a new one (I mean, just in case..), you've been though a lot! Hope the camera wasn't charging..
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 04, 2018, 12:31:07 am
It's not that bad.  The house was not damaged and no one was injured.

Yeah, thank goodness. :phew: Keeping my fingers crossed for your T&M gear that there aren't any more casualties.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2018, 02:03:03 am
..Also on the plus side, my trusty PACE soldering iron survived.
Maybe Aaron could send out a new one (I mean, just in case..), you've been though a lot! Hope the camera wasn't charging..

I think my Canon SX150 would be worth about a dollar now. 

It's not that bad.  The house was not damaged and no one was injured.

Yeah, thank goodness. :phew: Keeping my fingers crossed for your T&M gear that there aren't any more casualties.

I am using a different GPIB controller and have Labview working with it now.   There is a lot more testing to go.   Looks like a few other bits were damaged.  The big one so far if my beloved HP34401A that I bought brand new when they first came out.   That's been a great meter.  It's never given me any trouble in all these years.  I'm not sure I could find parts outside of getting a used one off ebay.   It going to be interesting to see how this plays out with the insurance company.  Take my advice, think about this before you have a problem.

On the plus side, my LeCroy DSOs have all survived. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 04, 2018, 02:56:32 am
I just took a look and Keysight still stocks quite a few parts for the 34401A. You can search their inventory (https://www.keysight.com/my/faces/fapHomePage.jspx) by part number (for something specific) or the model (to see everything that can still be ordered).

Note: Their parts search system is very unfriendly for use on mobile devices.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2018, 03:38:13 am
My old HP VNA appears to have survived for the most part.

Went to check the Signal Hound and other USB devices, knowing full well what a poorly designed that bus is.    Sure enough, everything was dead.  After checking the PC port (I had to add a board in the PC to get that Signal Hound stable), the cables, then the hub, it turns out the hub was dead.  I have two of these Anker hubs.  Made a swap and everything fired up.  :phew:   

Picture showing my secret to automating many of the tests I have shown.
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 04, 2018, 04:22:39 am
Joe, I’m sorry to hear the news. Perhaps the ghosts of tortured meters past, got together for their own revenge.....

Glad everyone is ok.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 04, 2018, 04:44:46 am
My old HP VNA appears to have survived for the most part.

 :phew:

Quote
Went to check the Signal Hound and other USB devices, knowing full well what a poorly designed that bus is.    Sure enough, everything was dead.  After checking the PC port (I had to add a board in the PC to get that Signal Hound stable), the cables, then the hub, it turns out the hub was dead.  I have two of these Anker hubs.  Made a swap and everything fired up.  :phew:   

Hubs as surge protectors. Noted.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 04, 2018, 10:17:13 am
In the early days of USB, nobody cared for transient supression, thus peripherals fell like files. Unless it is a crappy product, nowadays they should have suppressors all around, especially if it is a higher quality product as Anker.
Title: Re: Handheld meter electrical robustness testing.
Post by: HoracioDos on July 04, 2018, 12:24:01 pm
Hello Joe. I'm sorry to hear that. When these things happen you start thinking like a prepper. I'm sure that once you have repaired or replaced your equipment you will be thinking about how to avoid lightning strikes again.
Luckily we only lost a TV set many years ago. Here the insurance companies pay up to a predefined amount of money for electronic equipment according to your contract.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 04, 2018, 01:08:15 pm
Here the insurance companies pay up to a predefined amount of money for electronic equipment according to your contract.

I think that's universal.

Also: If stuff isn't individually itemized on the policy then you'll get a percentage of the total value of the policy, as determined by them. Usually a pittance.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 04, 2018, 01:37:57 pm
We look forward to a new series of videos with joe adding extra MOVs and gas discharge tubes to his house.

(and painting the roof with corona dope)

 :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2018, 03:48:21 pm
Hello Joe. I'm sorry to hear that. When these things happen you start thinking like a prepper. I'm sure that once you have repaired or replaced your equipment you will be thinking about how to avoid lightning strikes again.
Luckily we only lost a TV set many years ago. Here the insurance companies pay up to a predefined amount of money for electronic equipment according to your contract.

I'm not too concerned. Chances of it happening again in my lifetime would be rare.  I may need to adjust my insurance for the lab.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2018, 07:28:00 pm
Remember the days when you could actually repair your own equipment?   If we really wanted to limit the amount of ewaste, we should mandate companies to produce service manuals and spare parts for anything electronic related....   

Pushing ahead with no schematics....
They used 7438s which I did not have on hand.  I did have some 7403s to allow me to troubleshoot the rest of it.  I was out of LS14s and used some LS04s.   No cracks in any of the ICs. 

Next...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 04, 2018, 08:56:12 pm
I believe I have identified all of the bad parts required to repair my equipment, including my old HP meter.  Everything is in stock and on order.   There were no signs of an arc any anything.  Even the surge protectors all look fine.  It's very strange.

Now to more pressing problems.  The garage door...  Note the spark gaps in the upper right.   To the left there is an exposed copper trace.  Follow that to the top ground plane the the spark gaps return to.  Note, there is no copper.  You can just see to the right of the plastic mounting bracket where it stopped.  A few other traces are gone as well.   


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 07, 2018, 05:55:49 pm
Meter testing has gone off the tracks.

If you have watched my videos, you know I do all of my own repairs and have shown where I have modified a few meters to give people a better idea how they work.   One thing I have mentioned is how important it is to keep things clean.   One of the main solvents I use is isopropyl alcohol but I have also mentioned I use a product called ProClean.   Much of the electronics I work on will have plastic which can be attacked by some cleaners.  I have a friend who tried to clean there laptop once and the case disintegrated over the next few weeks.   :-DD  I pretty much settled on ProClean several years ago. 
   
I use a about a can a year and have been trying another MicroCare product called VERICLEAN.    I've attached a few pictures showing the chemicals they use for the two different products.  I never saw a case where the VERICLEAN damaged plastic.  It does a good job cleaning but if you watch, what I normally do is spray a swab then use that to clean the board.  The VERICLEAN drys faster than the ProClean so I seem to use more off it.   If I have to use a bristle brush to help break things up, the ProClean does a better job.    With the ProClean, if I want it to dry fast, I use the heat gun.  Just a few quick passes and instant dry.   

With these latest repairs, I just ran out of the DC1 and decided to go back to the ProClean.    No, I don't work for MicroCare and I am not a distributor for them.  Just thought I would show what I use. 

https://electronics.microcare.com/products/clean-flux-remover-vericlean/
https://electronics.microcare.com/products/rma-flux-remover-proclean/     

Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on July 07, 2018, 06:44:19 pm
I guess I don't much see the point in buying ProClean, unless it is for the convenience of a spray can. It is just a mixture of isopropyl alcohol and ethyl alcohol with HFC 134a as a propellant. You could buy IPA and "green" denatured alcohol and mix up something similar yourself.

(Evidently, the theory is that pure IPA has some limitations as a solvent. Adding some ethanol helps to dissolve those hard to remove deposits. I suspect adding a little distilled water may also be helpful. Experimentation would be needed.)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 07, 2018, 07:03:34 pm
The pressurized delivery is useful in tight areas as well as for general degreasing of small parts (not just flux removal). For open board areas I concur that a bottle of the ingredients and brush/swab is more economical. Right tool for the job, etc.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 07, 2018, 07:23:47 pm
They offer a brush applicator and also the extended trigger like I show.  For the amount I use, I would rather have the sealed can of a known mixture.  But to be clear, I am not suggesting you shouldn't use your WD-40 gasoline break cleaner mixture to work on your $80,000 scope.   :-DD    I'm not getting any sort of kickback and just offering what it is that I have used over the years.   The iso is cheap and again, this is my primary cleaner.  I keep a bottle in the lab and that's all it gets used for.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Kean on July 08, 2018, 11:16:40 am
I've not had a good history with pressurised cans of solvent.  For me they regularly seem to end up with no propellant but still plenty of solvent.  Same with cutting fluid for the machine tools.

I switched to 5 litre bulk containers of IPA and now I just buy it in a 20 litre drum (that should last a couple of years!).  I decant from the bulk containers into various dropper and spray bottles around the workshop.  It is so much cheaper in bulk form, and it means you don't hesitate to use a bit more solvent to actually wash away deposits properly.  Also great for filling the ultrasonic cleaner, although I tend to mostly use distilled water and SWAS safewash for that.

I also keep a tin or two of stronger solvents (e.g. Ultrasolve) for those special occasions where you're not worried about damaging plastics.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 08, 2018, 12:06:18 pm
I've not ran into low pressure with the ProClean.  I like that nothing gets into the can.  I use new swabs in the  isopropyl and seal it every time but's it's still open to the environment.   

I imagine I go through 470ml of isopropyl every three years or so.  For me, it's not a major expense compared to what I am normally working on.  With swabs, gloves, cleaners, maybe $20/year?       

There was an episode of AmpHour where they had a previous employee from Fluke come on the show.  It was one of the times I wished they had just gave him the mike and let him talk.  One of the things he talked about was cleaning the meters.    I've ran into problems with it making videos where I have shown errors in a reading and have to go back in and do a better job.   Not suggesting the free HF meters need that level of cleaning.   :-DD   
 
Short paper on solvents that may be of interest.   It's only about a page long and easy reading.  It talks about the common chemicals used and why/where  they are used.   
https://www.smta.org/chapters/files/smta-gdl_getting_pcbs_really_clean.pdf (https://www.smta.org/chapters/files/smta-gdl_getting_pcbs_really_clean.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on July 08, 2018, 03:26:12 pm
Quick tip with those cans where the propellant gas charge has been used up, but the can is otherwise still fine, and half full of the product, is to take a regular can of lighter gas ( the type you use upside down to fill a gas lighter, typically a 300ml can available for $3 from most places that sell cigarettes and Rizla papers), pull the nozzle off the can, and use one of the supplied red plastic adaptors to refill the can. Works well, you get a new charge of good R600 (propane) in the can to pressurise it, and most cans use propane as a propellant in any case. Have used it on assorted things, including expensive bottles of perfume which had had the propellant evaporate through the rubber seals with time.

Otherwise you have to get a small container, preferably one with a pop off lid, and decant the liquid into it. Pop off lid over screw type, as the liquid will gas off considerably with time, as the dissolved propellant slowly evaporates.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 08, 2018, 07:50:40 pm
I guess you could stomp on them as well.  At least then you know you are not introducing any possible contamination. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 08, 2018, 08:15:06 pm
Spending 11 hours yesterday in the lab, compressed into 17 minutes...

https://youtu.be/40TaqXOIrHo
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 09, 2018, 05:19:42 am
That was quite the sod launcher. :o
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 05:49:20 pm
Was thinking all the side projects are done, everything is repaired.  Time to start working on the next videos.   One is actually a meter. 

So, more dead electronics.   I have a device that has several transistors, microcontroller, switches and such.  This device was not plugged in at the time of the strike.  I went to use it and it was totally dead.  I opened it up.  They use a glass fuse.  The glass was shattered.  Transistors were split in two.  Several traces were gone.  Again, it was not plugged in. 

Care to guess what this device was?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 17, 2018, 05:51:25 pm
Harbor Freight DMM?  :-DD

That or an AM/FM radio. I could see something with an antenna being "fried" by EMP.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 08:08:27 pm
Harbor Freight DMM?  :-DD

That or an AM/FM radio. I could see something with an antenna being "fried" by EMP.

HF meter is a very good guess.  I'll give you another clue, the transient did not come through the power cord, or through the air.  You know it hit a tree.... 

So, several traces, three transistors, exploded glass fuse and a shorted 104 cap.    After about 2 hours of work, I tried to run it and the microcontroller is hot.  No other activity.  On the plus side, easy to order a new one and get on with the next video...  I've got a date with a cheap meter and want to design the most unimpressive differential probe ever... 
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 17, 2018, 08:39:15 pm
Cable box?
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 17, 2018, 09:07:22 pm
So, more dead electronics.   I have a device that has several transistors, microcontroller, switches and such.  This device was not plugged in at the time of the strike.  I went to use it and it was totally dead.  I opened it up.  They use a glass fuse.  The glass was shattered.  Transistors were split in two.  Several traces were gone.  Again, it was not plugged in. 

Holy smokes! :o How in the world did it shatter the fuse? Was it that close to the tree?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 09:12:36 pm
Cable box?

Another very good guess.  If I only watched TV.   :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: Vgkid on July 17, 2018, 09:15:13 pm
Internet modem(our old one had a fuse)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 09:18:37 pm
So, more dead electronics.   I have a device that has several transistors, microcontroller, switches and such.  This device was not plugged in at the time of the strike.  I went to use it and it was totally dead.  I opened it up.  They use a glass fuse.  The glass was shattered.  Transistors were split in two.  Several traces were gone.  Again, it was not plugged in. 

Holy smokes! :o How in the world did it shatter the fuse? Was it that close to the tree?
The fuse is in-line with the secondary of a power transformer.  The primary would normally go to the AC outlet.   It was not plugged in and that glass shattered like what I have shown many times with my testing.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 17, 2018, 09:19:01 pm
Harbor Freight DMM?  :-DD

That or an AM/FM radio. I could see something with an antenna being "fried" by EMP.

HF meter is a very good guess.  I'll give you another clue, the transient did not come through the power cord, or through the air.  You know it hit a tree.... 

So, several traces, three transistors, exploded glass fuse and a shorted 104 cap.    After about 2 hours of work, I tried to run it and the microcontroller is hot.  No other activity.  On the plus side, easy to order a new one and get on with the next video...  I've got a date with a cheap meter and want to design the most unimpressive differential probe ever...
Wow... the sprinkler system then took quite a hit. I can imagine, as the "step voltage" is quite high.

("step voltage" is a technical term we used in Brazil to name the difference of potential between a "living thing's" feet while walking in the ground close to an electrical event such as a lightning strike - this was particularly troublesome for cattle farmers).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 09:23:48 pm
Internet modem(our old one had a fuse)

Well, that modem was dead for sure.  As a matter of fact, the coax enters the house and goes to the modem.  That's it.   And again, it hit the phone lines which are not connected to anything.  It also I suspect caused a huge common mode voltage on the mains which I suspect damaged some of my test equipment that was still plugged in but turned off at the time at both the equipment and power strips. 

So let me give you another clue.  To replace this device will cost me between $50 and $100.  The old one uses a National COP if anyone remembers them. 



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 09:28:45 pm
Harbor Freight DMM?  :-DD

That or an AM/FM radio. I could see something with an antenna being "fried" by EMP.

HF meter is a very good guess.  I'll give you another clue, the transient did not come through the power cord, or through the air.  You know it hit a tree.... 

So, several traces, three transistors, exploded glass fuse and a shorted 104 cap.    After about 2 hours of work, I tried to run it and the microcontroller is hot.  No other activity.  On the plus side, easy to order a new one and get on with the next video...  I've got a date with a cheap meter and want to design the most unimpressive differential probe ever...
Wow... the sprinkler system then took quite a hit. I can imagine, as the "step voltage" is quite high.

("step voltage" is a technical term we used in Brazil to name the difference of potential between a "living thing's" feet while walking in the ground close to an electrical event such as a lightning strike - this was particularly troublesome for cattle farmers).

BINGO!!! We have a winner!!!  :-DD   

The solenoids are very close to that tree.  I checked their resistance and cycled them.  Everything appears fine.     
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 17, 2018, 10:17:51 pm
“Hey God, there is this dude down there that likes to torture innocent meters with voltage transients.”
GOD: “Really, well let me show him what a real TRANSIENT is!”

Nah, I’m sure it’s just a one in a million coincidence.....
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 17, 2018, 11:28:23 pm
I've seen bigger transients captured on Youtube.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 17, 2018, 11:55:10 pm
So, more dead electronics.   I have a device that has several transistors, microcontroller, switches and such.  This device was not plugged in at the time of the strike.  I went to use it and it was totally dead.  I opened it up.  They use a glass fuse.  The glass was shattered.  Transistors were split in two.  Several traces were gone.  Again, it was not plugged in. 

Holy smokes! :o How in the world did it shatter the fuse? Was it that close to the tree?
The fuse is in-line with the secondary of a power transformer.  The primary would normally go to the AC outlet.   It was not plugged in and that glass shattered like what I have shown many times with my testing.

Ah, no wonder.

Wow... the sprinkler system then took quite a hit. I can imagine, as the "step voltage" is quite high.

("step voltage" is a technical term we used in Brazil to name the difference of potential between a "living thing's" feet while walking in the ground close to an electrical event such as a lightning strike - this was particularly troublesome for cattle farmers).

BINGO!!! We have a winner!!!  :-DD   

The solenoids are very close to that tree.  I checked their resistance and cycled them.  Everything appears fine.     

Yep, all the clues fit together.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 18, 2018, 02:02:11 am
Joe, I don't know what control unit you had or how many stations, but I recently replaced an ancient Toro unit (https://www.pluginreplacements.com/products/toro-model-ecx-8-zone-sprinkler-irrigation-timer-panel) with this one from Orbit (https://www.orbitonline.com/products/sprinkler-systems/timers/timers/easy-set-logic-all-weather-sprinkler-timer/9-station-outdoor-swing-panel-timer-2619). The advantage is that it is enclosed, which even in a garage it will probably have a long life (my older unit was eaten from rust coming from dust and spider webs).
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 18, 2018, 02:38:15 am
I've seen bigger transients captured on Youtube.

Sure, but they weren’t aimed at your home .... we just need a nickname for you now.

Lightning Joe?

Anyone????
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on July 18, 2018, 02:52:11 am
I've seen bigger transients captured on Youtube.

Sure, but they weren’t aimed at your home .... we just need a nickname for you now.

Lightning Joe?

Anyone????
:-DD

Nearly.......Joe Lightning ! ! !
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 18, 2018, 02:20:20 pm
Joe, I don't know what control unit you had or how many stations, but I recently replaced an ancient Toro unit (https://www.pluginreplacements.com/products/toro-model-ecx-8-zone-sprinkler-irrigation-timer-panel) with this one from Orbit (https://www.orbitonline.com/products/sprinkler-systems/timers/timers/easy-set-logic-all-weather-sprinkler-timer/9-station-outdoor-swing-panel-timer-2619). The advantage is that it is enclosed, which even in a garage it will probably have a long life (my older unit was eaten from rust coming from dust and spider webs).

Your ancient Toro controller was much newer than mine.  :-DD  Mine uses a mechanical timer with programming pins.  Why they even put a microcontroller in there, I am not sure. 

I started to look at new ones but they all take a battery for the RTC.  I don't need it to call my cell phone that I don't have have, update my blog or graph my water usage.  It's grass, it gets water, don't over complicate it.   :-DD

I've seen bigger transients captured on Youtube.

Sure, but they weren’t aimed at your home .... we just need a nickname for you now.

Lightning Joe?

Anyone????
:-DD

Nearly.......Joe Lightning ! ! !

Now I need some sort of Joe Lightning intro for all my videos along with an action figure.   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 18, 2018, 02:43:37 pm
Joe, I don't know what control unit you had or how many stations, but I recently replaced an ancient Toro unit (https://www.pluginreplacements.com/products/toro-model-ecx-8-zone-sprinkler-irrigation-timer-panel) with this one from Orbit (https://www.orbitonline.com/products/sprinkler-systems/timers/timers/easy-set-logic-all-weather-sprinkler-timer/9-station-outdoor-swing-panel-timer-2619). The advantage is that it is enclosed, which even in a garage it will probably have a long life (my older unit was eaten from rust coming from dust and spider webs).

Your ancient Toro controller was much newer than mine.  :-DD  Mine uses a mechanical timer with programming pins.  Why they even put a microcontroller in there, I am not sure. 

I started to look at new ones but they all take a battery for the RTC.  I don't need it to call my cell phone that I don't have have, update my blog or graph my water usage.  It's grass, it gets water, don't over complicate it.   :-DD
That was a concern of mine as well; both units (the old and the new) only use it for the RTC and to keep the programming in a power failure. I explicitly avoided the Wi-fi connected units because of that.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 18, 2018, 09:44:17 pm
I plan to start work on the Meterk MK01A soon.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 18, 2018, 09:53:58 pm
I plan to start work on the Meterk MK01A soon.
Kind of amazed it stayed in focus (if it only knew what was in store for it, it would be doing the 4th of July quiver)..  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 18, 2018, 10:04:58 pm
I plan to start work on the Meterk MK01A soon.

Joe Lightning STRIKES AGAIN!! Look forward to the $9.00 shootout....
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on July 18, 2018, 10:13:30 pm
Now I need some sort of Joe Lightning intro for all my videos along with an action figure.   :-DD   
Fits you quite well IMO Joe, when at home busting meters, sparks and smoke all over the place and when you're on the drag bike .....lightning fast !
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 19, 2018, 02:47:52 am
Nice job with that new "spare parts" diff probe, Joe.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 03:05:17 am
That was one fine "8 Mhz probe"  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on July 19, 2018, 09:37:11 am
Hi there, im looking forward to see how the mertek meter performs. In addition to comments on the video, could you show the ceramic fuses internals?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 12:43:40 pm
Hi there, im looking forward to see how the mertek meter performs. In addition to comments on the video, could you show the ceramic fuses internals?
I plan to pull both fuses apart after seeing where they open up at.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 12:56:47 pm
Nice job with that new "spare parts" diff probe, Joe.

That was one fine "8 Mhz probe"  :-+

It works better than I expected it would.  Looks like the price for the MICSIG DP10013 jumped $30 USD on Amazon since the last time I looked. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on July 19, 2018, 01:35:16 pm
Hi there

Is this the same  MICSIG DP10013  model  ?

https://www.ebay.com/itm/Micsig-Oscilloscope-1300V100MHz-High-Voltage-Differential-Probe-Kit-High-Quality-/123239228604?roken=cUgayN&soutkn=EvpMYC (https://www.ebay.com/itm/Micsig-Oscilloscope-1300V100MHz-High-Voltage-Differential-Probe-Kit-High-Quality-/123239228604?roken=cUgayN&soutkn=EvpMYC)

But off course you get the risk of getting stuck..
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 02:31:28 pm
Hi there

Is this the same  MICSIG DP10013  model  ?

https://www.ebay.com/itm/Micsig-Oscilloscope-1300V100MHz-High-Voltage-Differential-Probe-Kit-High-Quality-/123239228604?roken=cUgayN&soutkn=EvpMYC (https://www.ebay.com/itm/Micsig-Oscilloscope-1300V100MHz-High-Voltage-Differential-Probe-Kit-High-Quality-/123239228604?roken=cUgayN&soutkn=EvpMYC)

But off course you get the risk of getting stuck..
Hmm.. 161 listings with much better than avg prices, but only 32 feedback's? My nose is telling me :bullshit:
https://www.ebay.com/sch/dannuer/m.html?_trksid=p3692 (https://www.ebay.com/sch/dannuer/m.html?_trksid=p3692)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 02:39:49 pm
Hi there

Is this the same  MICSIG DP10013  model  ?

https://www.ebay.com/itm/Micsig-Oscilloscope-1300V100MHz-High-Voltage-Differential-Probe-Kit-High-Quality-/123239228604?roken=cUgayN&soutkn=EvpMYC (https://www.ebay.com/itm/Micsig-Oscilloscope-1300V100MHz-High-Voltage-Differential-Probe-Kit-High-Quality-/123239228604?roken=cUgayN&soutkn=EvpMYC)

But off course you get the risk of getting stuck..

Yes, but consider its $200 for shipping plus the price of the probe.   They will not sell very many like this.

Looks like it's $140 to $160 on eBay 
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 02:49:46 pm
For me it said shipping was free.. (a tempting way to toss $50 but I still smell :bullshit:)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 02:52:32 pm
Joe, how did that hot date go? (with the meter..) Is she smoking yet? :scared:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 02:59:54 pm
For me it said shipping was free.. (a tempting way to toss $50 but I still smell :bullshit:)

Really.  At $50 and free shipping, I would roll the dice.  Even at double that, I might pick one up.   I've never had a need for a high voltage differential probe at home.   They have a UT181A for a hundred bucks, $300 in shipping.   :-DD

One thing I was going to look at was the input impedance but I never finished the software for this analyzer to do it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 03:11:16 pm
Nope, free shipping for that too. Ebay says: "Based in China, dannuer has been an eBay member since Apr 17, 2018"  :bullshit:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 05:51:40 pm
Joe, how did that hot date go? (with the meter..) Is she smoking yet? :scared:

That meter is as buggy as the 121GW.  How come the two "reviews" that were posted don't show these problems??   They give it the old thumbs up, five star rating.. 

I'm currently watching the one that was posted in the comments.   At 13:20 it reminded me when I was attempting to get the Gossen apart.   The boot is tight.

He seems to like it as well.   
https://www.youtube.com/watch?v=MGtx1xbP8Hw (https://www.youtube.com/watch?v=MGtx1xbP8Hw)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 06:36:16 pm
If I understood his last comment, he has a store and plans to sell the meter.  Similar to the other review where the retired guy gets his free bling for giving thumbs up.   In my case, I could care less.  I'm getting nothing out of it. 


Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 07:11:34 pm
Don't know what to make of the guy frankly. He doesn't know that much but hey, that never stopped me much..  I've always been high on tinkering and lazy on math, but since I got my first job in electronic's in '76 at AEG Telefunken, I've been hooked.

I think anyone can "do a store" on Amazon. They do all the work and you just decided what products to recommend. I doubt there's much money in it, but I was thinking of your shortage of TTL when I saw that huge grab bag in his store.
https://www.amazon.com/shop/learnelectronics (https://www.amazon.com/shop/learnelectronics)
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 19, 2018, 07:16:57 pm
If I understood his last comment, he has a store and plans to sell the meter.  Similar to the other review where the retired guy gets his free bling for giving thumbs up.   In my case, I could care less.  I'm getting nothing out of it.

He’s going to put it in his “store”, wonder what the markup will be on a $9 meter? :)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 19, 2018, 07:30:39 pm
That's just the thing, it's not really a store. He ships nothing, it's just a URL forwarder (IMO) that gives him a dime if Amazon's honest.. I think there's kick-backs like, if there's enough action, providers might send him a kit.. whatever

All the thrills of being able to say, "I've got a store" and no real work..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 19, 2018, 08:18:46 pm
For a dime, maybe no bias then.   So far there are nine things I am not real impressed with.  But for $10, it's like the free HF meters.  You just can't bitch too much about them. 

The more problems I keep coming across, the less I am inclinded to try and improve it.   That said beyond the destructive tear down of the fuses, just let me know if there is anything else anyone would like to see.    Chemical and drop test are already covered.   Like every meter I run, don't wait until after to ask any questions you have.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on July 19, 2018, 10:55:37 pm
Hi there.

Does this device is prone to RF interference ? Can you pass the RF antenna to check that  its readings are changed ?

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 12:14:36 am
Hi there.

Does this device is prone to RF interference ? Can you pass the RF antenna to check that  its readings are changed ?

No problem.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 20, 2018, 01:48:44 am
Speaking of RF, putting it on the input jacks would be good too. The U127xA had an issue with that.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 02:05:28 am
Speaking of RF, putting it on the input jacks would be good too. The U127xA had an issue with that.

I've got you covered.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 03:52:14 am
I'm finished with testing and have started to work on editing.  Should be able to upload soon.  Watch for it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 20, 2018, 04:16:22 am
Thanks, Joe. Will keep my eyes peeled.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 20, 2018, 09:17:40 am
Nicely done as usual Joe! :-+  We can forget this one as a newbie best buy.. I'll post a link to his channel and see what he says.
*edit - He may not want to promote it in his "store" anymore. I was thinking about 3 of these as disposables but shipping to Canada doubles the cost, so yeah - I think not. Thanks for a really big sheww..!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 08:06:13 pm
Nicely done as usual Joe! :-+  We can forget this one as a newbie best buy.. I'll post a link to his channel and see what he says.
*edit - He may not want to promote it in his "store" anymore. I was thinking about 3 of these as disposables but shipping to Canada doubles the cost, so yeah - I think not. Thanks for a really big sheww..!

I read your post.  Here is a partial list if what I see as the MK01A's shortcomings:



Also, I have updated the spreadsheet to include this meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 20, 2018, 09:43:18 pm
Since a "real review" now exists, maybe I should remove those comments? As y'all know, I preview a lot of channels for sharing and I've seen of lot of "staged pro's" (in Spanish and English) and this guy's OK. Any care to opine with a yea or nay?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 20, 2018, 09:54:07 pm
Shame on both of you for taking the time to destroy a man's way of living with blatantly useless reviews...  :-DD

I have some carefully crafted design decisions for you:

Nicely done as usual Joe! :-+  We can forget this one as a newbie best buy.. I'll post a link to his channel and see what he says.
*edit - He may not want to promote it in his "store" anymore. I was thinking about 3 of these as disposables but shipping to Canada doubles the cost, so yeah - I think not. Thanks for a really big sheww..!

I read your post.  Here is a partial list if what I see as the MK01A's shortcomings:

  • Battery can be installed incorrectly.  Even the UT61E has different dimensions in the battery holder for the pos/neg. If the user is not paying attention, he doesn't deserve a METERK!
  • There are no captive tabs on the large fuse holder to keep it in place if the meter is dropped.   The case also has nothing in the molding to secure it. Again, if you can't take care of your things, you don't deserve a METERK!
  • When ramping the 10A current input, the supplied leads failed before the 10A fuse blew. Ultimate input protection against arc flash!
  • I'm not even sure what to say about the glowing small fuse.  Well, it was a cheap unfilled ceramic body.  The type Fungus does not believe exist.  :-DD You are never satisfied, are you? Hey, at least is ceramic and not glass cheapies.
  • Capacitance will not zero out without adding an external capacitor.  Well, in order to use the capacitance meter you would need one capacitor anyways... What is the problem in adding one more?
  • Very slow auto ranging for a moderate sized capacitor.   The same for lower value resistors. Youngsters are so impatient these days...  :palm:
  • When in AC mode, selecting frequency will require a zero cross for the meter to read it.  A METERK! is designed for the audiophile crowd that tolerates only absolute purity on their sinewaves.
  • When in AC mode, cases like a a full wave rectified signal that is unfiltered can not be read. Exactly. How dare you submit a METERK! to such impure waveform?!? Blasphemy!
  • When in AC mode, is the input is and AC waveform with a DC bias, the meter may not display the correct value.  In my setup I show the meter reading between 4 volts and 42 volts. Read the two above.
  • When in DC mode, if the the input is an AC waveform with a DC bias,  the meter will not display the correct value. I don't know why you insist in feed the METERK! with such impurities... I think you are trying to corrupt its soul.
  • In frequency mode, the meter appears to be susceptible to 3KHz and will display low battery. This is to inform the user he is finally crossing the upper bandwidth of that impure audio system called POTS and entering a new dimension in audiophile domain.
  • With a 180MHz 20dBm signal (roughly 3V), the meter will display more than 50 volts. That frequency is too much even for the purest audiophile domain.
  • Why do they put the vias in the rotary switch pads?  You are not as famous as Dave yet. :)
  • The mA lead was not soldered.  There were no signs that the solder had wicked to the terminal. That shouldn't block the user from moving forward. Basic soldering skills for the hobbyist are critical for a solid career.
  • The stupid little piezo grill starter killed it.  The only meters that are damaged by that are UNI-Ts and the lowest of the low.  If the gun had killed it, I may have been alright with it but no, its the test that hardly does anything.   Shame on you for subjecting a METERK! to these abominations!


Also, I have updated the spreadsheet to include this meter.


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 10:11:12 pm
Since a "real review" now exists, maybe I should remove those comments? As y'all know, I preview a lot of channels for sharing and I've seen of lot of "staged pro's" (in Spanish and English) and this guy's OK. Any care to opine with a yea or nay?

Does it matter?  If you would like me to remove the screen capture, feel free to ask.   I really didn't see a problem with any of it.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 20, 2018, 10:13:30 pm
Nor me Joe, I review another Keysight guys channel's speaking in Portañol too..  :-DD (at least that's how it sounds to me..)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 10:13:47 pm
Shame on both of you for taking the time to destroy a man's way of living with blatantly useless reviews...  :-DD

I have some carefully crafted design decisions for you:

It's all so clear now!!  :-DD 



 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 20, 2018, 10:23:09 pm
I review another Keysight guys channel's speaking in Portañol too..  :-DD (at least that's how it sounds to me..)

The only thing that caught my eye with your posts was their first response where they write "I said "for low voltage home hobby"", yet they demonstrated the meter attached to the mains without a care in the world.   I guess they have never seen a large transient on their lines.    Oh, that's right, the upstream fuses, transformer and lines limit the energy.  That is until your tree gets hit and bypasses the whole mess.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on July 20, 2018, 11:21:11 pm
I review another Keysight guys channel's speaking in Portañol too..  :-DD (at least that's how it sounds to me..)

The only thing that caught my eye with your posts was their first response where they write "I said "for low voltage home hobby"", yet they demonstrated the meter attached to the mains without a care in the world.   I guess they have never seen a large transient on their lines.    Oh, that's right, the upstream fuses, transformer and lines limit the energy.  That is until your tree gets hit and bypasses the whole mess.   :-DD
Now who knows about transients like Lightning Joe?
(something tells me by now, you've got hockey-puck size GDT's in your electrical panel..)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 21, 2018, 12:56:25 am
Nor me Joe, I review another Keysight guys channel's speaking in Portañol too..  :-DD (at least that's how it sounds to me..)
Who is that, Cliff? I would love to take a look at the video.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 21, 2018, 01:52:25 am
Nicely done as usual Joe! :-+  We can forget this one as a newbie best buy.. I'll post a link to his channel and see what he says.
*edit - He may not want to promote it in his "store" anymore. I was thinking about 3 of these as disposables but shipping to Canada doubles the cost, so yeah - I think not. Thanks for a really big sheww..!

I read your post.  Here is a partial list if what I see as the MK01A's shortcomings:

  • Battery can be installed incorrectly.  Even the UT61E has different dimensions in the battery holder for the pos/neg. 
  • There are no captive tabs on the large fuse holder to keep it in place if the meter is dropped.   The case also has nothing in the molding to secure it.   
  • When ramping the 10A current input, the supplied leads failed before the 10A fuse blew.
  • I'm not even sure what to say about the glowing small fuse.  Well, it was a cheap unfilled ceramic body.  The type Fungus does not believe exist.  :-DD
  • Capacitance will not zero out without adding an external capacitor. 
  • Very slow auto ranging for a moderate sized capacitor.   The same for lower value resistors.
  • When in AC mode, selecting frequency will require a zero cross for the meter to read it. 
  • When in AC mode, cases like a a full wave rectified signal that is unfiltered can not be read.   
  • When in AC mode, is the input is and AC waveform with a DC bias, the meter may not display the correct value.  In my setup I show the meter reading between 4 volts and 42 volts.
  • When in DC mode, if the the input is an AC waveform with a DC bias,  the meter will not display the correct value.
  • In frequency mode, the meter appears to be susceptible to 3KHz and will display low battery.
  • With a 180MHz 20dBm signal (roughly 3V), the meter will display more than 50 volts.
  • Why do they put the vias in the rotary switch pads?   
  • The mA lead was not soldered.  There were no signs that the solder had wicked to the terminal. 
  • The stupid little piezo grill starter killed it.  The only meters that are damaged by that are UNI-Ts and the lowest of the low.  If the gun had killed it, I may have been alright with it but no, its the test that hardly does anything.   


Also, I have updated the spreadsheet to include this meter.

Thanks, Joe. You've developed quite the suite of functionality tests. Great job catching several issues that, until your video, I hadn't seen anyone else mention about this DMM.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on July 21, 2018, 09:03:30 am
...
  • I'm not even sure what to say about the glowing small fuse.  Well, it was a cheap unfilled ceramic body.  The type Fungus does not believe exist.  :-DD

I believe!  \$\Omega\$
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 21, 2018, 03:54:53 pm
Thanks, Joe. You've developed quite the suite of functionality tests. Great job catching several issues that, until your video, I hadn't seen anyone else mention about this DMM.

The testing has definitely evolved into more of a review compared to just running the one transient test.  The time involved now to look at a good meter can be several days but a side effect is I don't look at too many meters now.         

I responded to people who asked me about running the 121GW that I thought maybe a year after the kick start I would have a look.  That's only what, four months away and it looks like they still have not shipped all of the units and they still have some of the problems that I saw in the preproduction unit.   I assume that this is partly why we have not seen an announcement for a release date.

...
  • I'm not even sure what to say about the glowing small fuse.  Well, it was a cheap unfilled ceramic body.  The type Fungus does not believe exist.  :-DD
I believe!  \$\Omega\$
:-DD :-DD  I couldn't let you sit on the sidelines. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 21, 2018, 05:43:05 pm
I havn't seen a post like this in a while.   
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on July 21, 2018, 06:17:10 pm
I havn't seen a post like this in a while.

“who in their right mind.....?”

I’ll answer that;

LIGHTNING JOE, that’s who!!!
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on July 21, 2018, 06:27:28 pm
Man, that is probably part of the crowd that can only read headlines and does not go past the second paragraph.

That gives me one additional suggestion for a test: connect the meter to the coil pins of a 120VDC relay (or any large inductor) and scratch its leads on a DC source. That could maybe convince this person that a real-world scenario could damage his beloved cheapie.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 21, 2018, 06:34:03 pm
When I have seen where people have posted about damaging their meters, I will take the time to ask what happened.  I am really interested if they damaged the front end.  Not that I am trying to embarrass them but to see if there is some new test I should consider.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on July 21, 2018, 07:12:03 pm
I can just picture Joe, standing in front of a struck tree, looking at it for a while. And then, with a mocking smile on his face, he looks up and say quietly:"Challenge accepted ....."  :-DD

Yeah, people don't have a clue. I live in a city, even high voltage distribution is underground, and electric network really does damp things a lot..
But as you go few kilometers off the city centre, it gets waaay more dangerous.. Appliances and electronics go "poooof" all the time.

Regards
Sinisa
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on July 21, 2018, 07:39:30 pm
The Mertek ended quite soon as many uni-t's, by the ESD. The video was very elaborated and to be honest maybe the expectations were worse, like failing at the rectified 230V on the temperature / mV range.

If are starting and wanna test  some circuits to 230V or 110V use back to back transformers to isolate, reduce the amount of energy from the mains. This transformers can be found from older power bricks |O cell phone , game consoles, cordless phones power which didn't use switched power supplies.

Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on July 21, 2018, 07:41:07 pm
That lightning hit was only a minor hit, all the wires stayed in the walls.  >:D
When lightning hits close by stuff like CAT rating do not mean much, you might get a million volts and lots of kA.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 21, 2018, 07:56:35 pm
The Mertek ended quite soon as many uni-t's, by the ESD. The video was very elaborated and to be honest maybe the expectations were worse, like failing at the rectified 230V on the temperature / mV range.

If are starting and wanna test  some circuits to 230V or 110V use back to back transformers to isolate, reduce the amount of energy from the mains. This transformers can be found from older power bricks |O cell phone , game consoles, cordless phones power which didn't use switched power supplies.

It's not even so much that it was damaged by the ESD as it was damaged by the do nothing grill starter ESD.    If you watch the first five minutes or so of this video, you can see how that  grill starter compares with my home made ESD gun and the IEC standards.     

https://youtu.be/Qimtx8z6FUQ

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on July 21, 2018, 11:12:31 pm
Hi there.

That gives the clarity of the pulse from the various devices and some sort of levels. I remember this from the uni-t ut-181A , this video that you shared looks like a follow-up . I might be wrong...  Is that what you're ESD gun is replicating towards the IEC regarding EMC, but with lower energy?




The spark at 7:56 of the video reminds me the arc mosquito zapper, but much powerfull, looks like when you get zapped also on your car by static discharge... 



Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on July 22, 2018, 12:34:43 am
I havn't seen a post like this in a while.

I wouldn't be surprised that there are actually many more who think that way. They just don't bother to post.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2018, 12:54:31 am
Hi there.

That gives the clarity of the pulse from the various devices and some sort of levels. I remember this from the uni-t ut-181A , this video that you shared looks like a follow-up . I might be wrong...  Is that what you're ESD gun is replicating towards the IEC regarding EMC, but with lower energy?

Yes, it was a follow up to the 181A.   I had enough people send me comments that the grill started was not realistic, so I decided to attempt to follow the IEC waveforms.   Yes it's a little on the weak side still.  I did go back and test every meter I had (that was working and had survived the grill starter) using the new gun.  Every one of them survived. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 22, 2018, 01:08:19 am
I havn't seen a post like this in a while.
I wouldn't be surprised that there are actually many more who think that way. They just don't bother to post.
I'm sure you are correct.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 15, 2018, 05:33:16 pm
A few people had asked about running a 189.  Something like this may not be too bad.  It's already dead and fairly cheap.  Then again, if someone needed some parts....


https://www.ebay.com/itm/FLUKE-189-TRUE-RMS-MULTIMETER-WITH-LEADS-AND-BAG-FOR-PARTS-OR-REPAIR/263878907548?hash=item3d7068969c%3Ag%3AhjoAAOSwxnlbcyeV&_pgn=2&_sacat=0&_nkw=189+fluke&_from=R40&rt=nc (https://www.ebay.com/itm/FLUKE-189-TRUE-RMS-MULTIMETER-WITH-LEADS-AND-BAG-FOR-PARTS-OR-REPAIR/263878907548?hash=item3d7068969c%3Ag%3AhjoAAOSwxnlbcyeV&_pgn=2&_sacat=0&_nkw=189+fluke&_from=R40&rt=nc)

Title: Re: Handheld meter electrical robustness testing.
Post by: retiredcaps on August 15, 2018, 06:59:41 pm
A few people had asked about running a 189.  It's already dead and fairly cheap.
It will likley go for more than $50 USD, but then I haven't participated in almost 4 years now in Fluke ebay auctions. 

Sharp eyed viewers will see battery leakage? on the terminals and left side screw.  Possible pcb corrosion as well.

Fuses might be blown as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 15, 2018, 07:13:04 pm
The (white) corrosion on the battery terminals and nearby screws looks like water ingress. I would say it got dunked.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 15, 2018, 07:17:35 pm
A few people had asked about running a 189.  Something like this may not be too bad.

When you ran the first Fluke 87 it caused an outcry because it wasn't a brand new meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 15, 2018, 08:34:52 pm
Yea, that vintage 87V will be a thorn in the test data forever.  Crazy meter.  I think the outcry was because I was killing a Fluke brand meter and not just any Fluke brand meter, but what is touted as the "golden standard"   :-DD.   Where I actually use that old Fluke 189s, that new 87V just sits in its box with its chattering switch.     

There is no way to run a new 189.  $60, it would be fun to play with.   I've sent more costly meters to their graves.   It may also be fun to cycle the switch on such an old meter.   

Still, this one looks in better mechanical condition than the one my friend had given me.   One of you Fluke 189 fanboys needs to step up and save this meter.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 15, 2018, 08:42:12 pm
You know you increased the perceived value of this meter, right?  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 15, 2018, 09:25:24 pm
You know you increased the perceived value of this meter, right?  :-DD
:-DD  I swear it's not my auction and I have no idea who is selling it.   :-DD    If it had a buy it now option for $50, I would take it and do what I plan to with it.   Then sign it with a grim reaper 14 KV or Bust logo and relist it as genuine Joe Smith artwork for $1 (parts only).   :-DD    Maybe I could break even.  :-DD
 
Title: Re: Handheld meter electrical robustness testing.
Post by: retiredcaps on August 16, 2018, 02:25:49 am
Re 189 auction, I checked the seller's history and saw this.  A buyer bought the 189 previously and wrote

"Not as described; meter clearly tampered with after photos in auction. Disputed."

Not sure what it means, but buyer beware.  Especially when previous buyer bought it for $118.15 USD.
Title: Re: Handheld meter electrical robustness testing.
Post by: retiredcaps on August 16, 2018, 02:29:22 am
4 years ago, I could probably guess each bidder despite the *** obscurity.
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 16, 2018, 04:08:34 am
That 189 sounds familiar. Yes, this was the original listing (beware, eBay is likely to auto-redirect you to a different listing):

https://www.ebay.com/itm/-/253732641476 (https://www.ebay.com/itm/-/253732641476)

It didn't function at all (despite the original description saying that it was working intermittently), was missing an additional screw (unlike the listing photo), had no fuses, and no batteries. Interestingly, the current listing has fuses and batteries in it.

Anyway, I didn't buy it, but I know the person who did and he returned it because it clearly was not as described. The seller was pretty defiant about giving a refund, too.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 06:47:10 am
I see the history but the link does take me to the recent listing.  Personally, I could care less about the batteries, blown or missing fuses, missing screws, cracks in the lens and corroded battery pins.  The goal is not to restore it.  As long as no unskilled wannabe's have attempted  "repairs", it would be worth $60.  If it's been touched with an iron, price drops to $10.  That's my disposal fee!   :-DD   

I closed my eBay account about the time they bought Paypal and looks like I can't do anything without making a new one.  I would like to see the condition of the board.  Still virgin, I may take a crack at it.   

Bitseeker, if you don't mind, please ask the person who bought it and returned it if they took and pictures of the internals that you could post. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 16, 2018, 06:56:52 am
I gotcha. Unfortunately, he didn't open it in order to minimize arguments about who did what to it and when. So, the state of the PCB is unknown.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 07:19:14 am
Ok,  thanks anyway.   Looks like I can't contact the seller without an account to see if they would remove the back cover.  Even just pop the accessory holder off and see if the calibration tamper proof seal is still intact.  Not a great indicator but may be safer than having someone try and open with no ESD protection in a dirty warehouse with a leaking roof with dirty hands and a jackknife for a screwdriver.    :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 07:34:12 am
The asking prices are a bit high IMO.  I would rather have a new Brymen BM869s.  Some of the ads a funny.  $200 for the meter, $50 for shipping.   :-DD   This one looks decent.  They offer a 30 day return.   Doubt a butcher has been into it.  May  make for a more valid test than having to repair one.     

https://www.ebay.com/itm/Fluke-189-True-RMS-Digital-Handheld-Multimeter/132719306368?hash=item1ee6afe680:g:wDcAAOSw0BdbWhpV (https://www.ebay.com/itm/Fluke-189-True-RMS-Digital-Handheld-Multimeter/132719306368?hash=item1ee6afe680:g:wDcAAOSw0BdbWhpV)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 07:44:01 am
scratch that. not the pictures of what you will receive.   :-DD :--  at least when you buy a pos, you know its a pos going into it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 16, 2018, 09:04:18 am
I am not going to buy it! There are mossing items! "Power cord not included" :P

IME a Fluke tends to attract buyers and the 187/189 are considered excellent meters. Over the years I sell a meter here and there on the local classified ads (Craigslist) and the only one that garnered a wide number of interested people was the 179. The distant second was a U1233 from Keysight.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 06:59:56 pm
Missing power cords a deal breaker for sure.   

Looks like someone put a bid in on the $50 one.  Hopefully it finds a good home vs me sending it to the recycle bins.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 16, 2018, 08:01:42 pm
why not blow one to hell, then re-list it on EvilBay?  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 08:20:18 pm
why not blow one to hell, then re-list it on EvilBay?  >:D

Will it increase the value?   :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 16, 2018, 09:12:50 pm
why not blow one to hell, then re-list it on EvilBay?  >:D

Will it increase the value?   :-DD
If it has the grim reaper drawn in joeqsmith style...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 16, 2018, 10:22:29 pm
hummm shiny contacts and doesn't work... Fluke 189


https://www.ebay.com/itm/Fluke-189-Digital-Multimeter-SN-79380617/292672980300?hash=item4424ab454c:g:tBwAAOSwzf9bay8T (https://www.ebay.com/itm/Fluke-189-Digital-Multimeter-SN-79380617/292672980300?hash=item4424ab454c:g:tBwAAOSwzf9bay8T)


:DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 10:41:00 pm
Price is a bit high for what I plan to do with it, but then again.   

When my friend gave me the 189, I thought about doing some sort of review and went looking to see what was out there.  Came across this video.  Just watched it again and it's still just as funny.   He starts talking about EEVBLOG and watching Dave stress an old Fluke and how upset he was about it.   Good stuff.  He's not going to like me putting 14KV across one!   :-DD
https://www.youtube.com/watch?v=DUwkuM3blsk (https://www.youtube.com/watch?v=DUwkuM3blsk)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 16, 2018, 11:15:10 pm
20Kv on this meter directly yeah... forget about CAT levels and HV probes.... Maybe another unit will be more pleasant but the effect will be almost the same for the owners of the Fluke 189. CATIII 1000V ???
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 16, 2018, 11:54:45 pm
I'm not thinking Fluke was going to cover that one with their life time warranty.  I wonder what they actually connected it to.  I'll ask.   Guessing a bit more than a grill starter.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 01:13:57 am
 :o :o :o   

https://articulo.mercadolibre.com.ve/MLV-489152168-multimetro-tester-fluke-189-para-repuesto-_JM
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 17, 2018, 01:17:29 am
Just... Throw it in the trashcan... Please...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 01:40:13 am
If I ran it, you know some Fluke fan would be upset.   I can hear it all now,  "You idiot, you destroyed a perfectly good meter!!"  Then Fungus would want me to drop test it and I'm thinking that a roll of electrical tape to hold it together may be cheating.   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 17, 2018, 03:17:12 am
The people who get so upset about destroying a DMM, do they realize what happens to new cars? ;D

https://www.youtube.com/watch?v=uiMR2VelgyQ (https://www.youtube.com/watch?v=uiMR2VelgyQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 03:29:24 am
To be honest, I don't believe so.  I see a lot of car analogies posted that go something like: 

"Wait, you just put 2000 volts across a meter that is clearly marked 600volts.  That would be like driving your car into a brick wall at 100 MPH and expecting it to be fine.  Your stupid."   :-DD  :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 17, 2018, 03:42:30 am
Well, that's a hoot and a half.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 17, 2018, 10:40:33 am
To be honest, I don't believe so.  I see a lot of car analogies posted that go something like: 

"Wait, you just put 2000 volts across a meter that is clearly marked 600volts.  That would be like driving your car into a brick wall at 100 MPH and expecting it to be fine.  Your stupid."   :-DD  :-DD   

600v continuous, 2Kv peak  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 17, 2018, 12:19:09 pm
To be honest, I don't believe so.  I see a lot of car analogies posted that go something like: 

"Wait, you just put 2000 volts across a meter that is clearly marked 600volts.  That would be like driving your car into a brick wall at 100 MPH and expecting it to be fine. 
 
I suspect they don't use this analogy for your rotary switch tests...

The crash tests do not test a car's limits, but instead the integrity of its occupants. The CAT rating test is closer to it but more stringent: the user cannot have any injury at all.

You test a meter's limits - similar to redline a car and see what rpm it will take for the engine to fail. This will give an indication of the tolerances a meter can withstand.

Your stupid."   :-DD  :-DD   
I love when people butcher the language when trying to call someone stupid...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 17, 2018, 12:28:21 pm
:o :o :o   

https://articulo.mercadolibre.com.ve/MLV-489152168-multimetro-tester-fluke-189-para-repuesto-_JM

Well that meter looks like it got a drop test or truck test, so one less do be done :DD ...

Grill starter? I think it was the grill related to the microhave transformer, a CRT tube or stun gun. Very low energy sources indeed... and precautions.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 01:05:10 pm
I haven't received too many comments on the switch life cycle testing.  The majority have to do with it not representing a real human.  Which is very true and I am always reminded of the time I loaned out my CEM meter and the person actually turned the switch past the dead stop.  One of this forums member's recently provided me with some pictures of a couple of Keysight meters from where they work.  They have a rubber coating on the knob and it has started to come off.   They look really bad. 

I'm not sure I could come up with a good analogy for the transient tests.   I would rather people not try and relate it to something that it's not. 

A meter is a final product, a cars engine is a sub component.  Of course the meter's front end is made up of subcomponents which really is the area I am interested in.   A driver could easily hold the accelerator to the floor with the car out of gear and see what happens.  There's no outside test equipment needed.  Just the driver.   The operator of a meter can't just turn the knob to transient mode and see if their meter self destructs.   Instead they need to do things like attempt to directly measure the output voltage of their gas grill ignitor.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 01:07:20 pm
Grill starter? I think it was the grill related to the microhave transformer, a CRT tube or stun gun. Very low energy sources indeed... and precautions.
MOT will not net them 20KV.  He said it happened at work.  I would think fairly low energy as well.  Maybe he will respond.
Title: Re: Handheld meter electrical robustness testing.
Post by: mqsaharan on August 17, 2018, 03:31:00 pm
If you do decide to run it, may I request to review it first, like you did with UT181A, with commentary about its front end, its hardware/software design and its working.
And if not may I still request a full review.

Regards,
Qasim.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 05:18:29 pm
Qasim,  as I mentioned, I thought about making a full review when I received the first one.   There are several videos on YT showing the 189 and with it being replaced by the 189 II and then the 289, I didn't see much of a point to spending any time on it.   

I have two of these so if I make a video showing a junk 189 and there is something specific that you wanted to see beyond what I show, I could possibly setup one of these meters for you as long as the test was not destructive.   The one my friend gave me was used in more a mechanical environment and the case is a bit rough but the insides are like new.  I doubt it ever measured line voltages.  The second one is a little newer and is in very good condition.

These seem to be some of the popular videos on the 189.
https://www.youtube.com/watch?v=Vikne0tCJms (https://www.youtube.com/watch?v=Vikne0tCJms)
https://www.youtube.com/watch?v=r2zVvb6SMwA&t=17s (https://www.youtube.com/watch?v=r2zVvb6SMwA&t=17s)
https://www.youtube.com/watch?v=RxKa51trkGw (https://www.youtube.com/watch?v=RxKa51trkGw)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 17, 2018, 10:05:06 pm
It was a HV power supply for a  display.   Make's sense from the video and how it looked.     
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 18, 2018, 12:13:01 am
I haven't received too many comments on the switch life cycle testing.  The majority have to do with it not representing a real human.  Which is very true and I am always reminded of the time I loaned out my CEM meter and the person actually turned the switch past the dead stop.  One of this forums member's recently provided me with some pictures of a couple of Keysight meters from where they work.  They have a rubber coating on the knob and it has started to come off.   They look really bad. 

I'm not sure I could come up with a good analogy for the transient tests.   I would rather people not try and relate it to something that it's not. 

A meter is a final product, a cars engine is a sub component.  Of course the meter's front end is made up of subcomponents which really is the area I am interested in.   A driver could easily hold the accelerator to the floor with the car out of gear and see what happens.  There's no outside test equipment needed.  Just the driver.   The operator of a meter can't just turn the knob to transient mode and see if their meter self destructs.   Instead they need to do things like attempt to directly measure the output voltage of their gas grill ignitor.

A rotary switch test for one of the pocket meters . About the Agilent / Keysight welll, here is the result of use and abuse... The rubber coating long gone:

https://photos.app.goo.gl/kwFDBmJrwJNuj6kE6

And it's recent sucessor B is also starting to wear off:

https://photos.app.goo.gl/RnyqrJofTbaow6er7

They do work fine but that is not very pretty
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 18, 2018, 12:27:20 am
I don't know how the switch could be left in that deteriorating state for so long. I'd have removed the rest of the rubberized coating long before it got to looking like that 1251A. ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 18, 2018, 01:31:49 am
I don't know how the switch could be left in that deteriorating state for so long. I'd have removed the rest of the rubberized coating long before it got to looking like that 1251A. ;)

That's what the person tried to do with that one Fluke for sale.   :-DD   What a mess.   

Under 2 days left, sitting steady at $50.  Wonder how much they bid.   Wonder if the seller bid on it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: mqsaharan on August 18, 2018, 03:50:15 am
Qasim,  as I mentioned, I thought about making a full review when I received the first one.   There are several videos on YT showing the 189 and with it being replaced by the 189 II and then the 289, I didn't see much of a point to spending any time on it.   

I have two of these so if I make a video showing a junk 189 and there is something specific that you wanted to see beyond what I show, I could possibly setup one of these meters for you as long as the test was not destructive.   The one my friend gave me was used in more a mechanical environment and the case is a bit rough but the insides are like new.  I doubt it ever measured line voltages.  The second one is a little newer and is in very good condition.

These seem to be some of the popular videos on the 189.

Hi Joe,
Thanks for the links. I remember watching the first one quite some time ago and I got bored right in the beginning and ended up fast forwarding most of the video. This time I skipped the beginning and watched the meter testing part again. You are right. There isn't much of a point in making yet another review video like that. Of course, here's your multimeter. If you like the face and the specs, get one. In a video you can see, hear the meter working. The technology isn't advanced yet to smell it too. But at least you get the feel of it.
The thing that I like about your videos is that you go farther than just basic show off. You functional test it at more points than the thing is described for in data sheet. How it actually respond to the signals that one encounter in (normal/special) use. It tells a bit more about the accuracy and capability of the meter. And then comes your famous robustness test.
I like your transient testing very much. Tells a lot more about the effort that has gone into designing the product and its safe operation. I know, you have said it numerous times, you are not checking their safety but your test ensures that too.

Please note that I am not forcing you to review it. As you have already mentioned it, its an old product, has been superseded by its successors. I asked for it only because you were already thinking about it, so I just wanted to put another vote there on the yes side.

Regards,
Qasim.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 18, 2018, 10:11:23 am
Qasim,

I think there are people who actually do feel they can control the channel but it never seems to work out.  :-DD   I'm not even sure what it would take for someone to force me to do something.  Hostages maybe.  :-DD   Now if UNI-T wanted to me to run a brand new UT181B that addresses my concerns and they were willing to send a couple to me knowing full well what I would do with them,  I may have to take them up on it.   :-DD  Likewise, Gossen could reach out to me with an improved version of the Ultra and I would be willing to give it another shot.    That's how you could force me but I don't think I have much to worry about.  My channel is small and it seems Brymen is really the only company interested in the tests.     

I just don't have a reason to watch feel good reviews like the first one.  I liked some of Dave's early reviews and found them to be very entertaining.  I adopted his 220V AC line test, with a twist.  That was about the only electrical stress test I saw any reviewer's performing and he was the only one.    When Dave made the video with his friend using the transient generator, I thought now you are on the right path.   Forget swimming with the meters and dropping them off the bridge.   

It's really the lack of electrical testing in these feel good reviews that got me interested in running my own tests.  That and comments like, "A free HF meter is as good as a Fluke".   I wanted to run tests that I saw damage my own equipment.  Low energy, high voltage.  Switch failure has been a problem, so I started to life cycle a few.  Chemical spray has got me before, so you see it now in some of my tests.   Again, I do it for myself but just make the videos to try and share what I find.  I'm better now about talking on camera but really have no interest in that part of it. 

Ever since my friend gave me his Fluke 189,  I have been curious how it would hold up.  For me, it's just such a nice general purpose meter like that BM869s.  I like it so much, I ended up finding a second one in very good condition.   You can count on me running one at some point and showing things like reverse engineering the front end and transient testing. 

It may be sooner than you think.  I need to get my $70 ready ...  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 18, 2018, 12:37:45 pm
Hi there.

At least the Fluke 189 doesn't have rubber on the rotary switch that come off after some years of usage... About the exterior case that's another story...




Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 18, 2018, 02:01:32 pm
Joe, I have a similar feeling about the "feel good" tests - I wonder if that is to get dopamine rush by folks validating their purchase. That or to advertise the meter on their online shop (I think it was you that mentioned that). As an example, one channel I loosely follow did recently a test on the ZT301 (AN8008 clone) and the meter had, straight out of the box, bad contacts on the rotary switch. He dismissed saying it was "normal" and gave a thumbs up to the meter. Oh well...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 18, 2018, 02:38:06 pm
The format is always something like this:

Thank's Banggood for sending me this product.  It's very accurate (of course without actually using it).  Thumbs up.  I will continue to use it.  Once again, thanks Banggood for providing me this product and thanks to all of my Patreon subscribers.  If you're not already a subscriber, please consider it.  Even a dollar a month will help me to continue to make great videos like this.   

I assume the idea is to try and maximize profits.  Free products to review, so no need to validate their purchases.  Of course everything gets a thumbs up.  That's what someone in sales does!  :-DD 

Looks like my competition is heating up.  :-DD
https://www.ebay.com/itm/FLUKE-189-TRUE-RMS-MULTIMETER-WITH-LEADS-AND-BAG-FOR-PARTS-OR-REPAIR/263878907548?hash=item3d7068969c:g:hjoAAOSwxnlbcyeV (https://www.ebay.com/itm/FLUKE-189-TRUE-RMS-MULTIMETER-WITH-LEADS-AND-BAG-FOR-PARTS-OR-REPAIR/263878907548?hash=item3d7068969c:g:hjoAAOSwxnlbcyeV)
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on August 18, 2018, 03:06:50 pm
When I'm critical of the 121GW everyone is telling me I am expecting too much, or I am not using it under the right conditions. So what is a reviewer to do?  :-\
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on August 18, 2018, 03:34:14 pm
When I'm critical of the 121GW everyone is telling me I am expecting too much, or I am not using it under the right conditions. So what is a reviewer to do?  :-\

Somebody asked that same question in DS7000 topic.
Answer is always the same: Check your findings twice so you are sure you are right. Than tell it like it is. But politely, in a civilized tone.  Enumerate pros and cons. Round it up and that's all you can do.
Making a good, rounded review is not easy.
On topic of expecting too much: If it's in a datasheet, it should work, up to spec. If datasheet has declared a functionality that functionality has to work and be usable.
No more, no less.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 18, 2018, 09:32:22 pm
Hi there

What about doing a robustness test on a fluke tester or voltage detector?

Example for the Fluke tester :

fluke 1651b test meter  https://ebay.us/pPhBFu

Voltage detectors:

UNI-T UT15C Waterproof Type Voltage Testers New #UNIT https://ebay.us/B6v0RG

Fluke T150 Voltage and Continuity Tester #Fluke https://ebay.us/QDYDJK
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 18, 2018, 10:53:33 pm
There is a link to a spreadsheet in the very first post of the meters I have ran.  If you look there, you would find that I ran the UT15C some time ago.  There's even a video on-line showing the tests I ran on it.   I was wanting to see if any UNI-T branded product was robust and figure this was their best shot.  Look at the data, it did not perform very well.

I try to stay away from probes like the ones you show as I doubt many hobbyist use them.  I also try to stay away from the used market.  Running a Fluke 189 will be an exception to a rule I rarely break.

Less than a day left, 4 bids, $61.  That's six of those METERKs I just ran.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 18, 2018, 11:48:19 pm
Thanks for the update.

Yeah another CAT overated product but not bad for a UNI-T :D that was not modified. Yeah that 189 if it survives will be  more usefull than 6 MERTEK's, since it has logging capability.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 19, 2018, 12:00:55 am
At $61, they could buy a brand new UNI-T UT61E with data logging and a free battery and still have enough money left for some cheap fuses.     
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 19, 2018, 12:56:57 am
But the UT61E still wouldn't be Fluke yellow. :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 19, 2018, 02:03:38 am
Dip it.   :-DD

https://www.amazon.com/Performix-11602-6-075815116024-Yellow-Plasti/dp/B000ZN1T16 (https://www.amazon.com/Performix-11602-6-075815116024-Yellow-Plasti/dp/B000ZN1T16)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 19, 2018, 02:23:51 am
Touché! :clap:
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 19, 2018, 10:18:17 am
And here is the rebranded model, yellowish ... Hope for the price is the GS model... Still gonna be done with grill starter and there goes the meter :P

https://pt.farnell.com/tenma/72-10415/dmm-handheld-auto-manual-4-5digit/dp/2499516


Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 19, 2018, 11:10:10 am
i hate yellow equipment, it makes it look like i robbed the back of a telephone-company van!!!
in the u.k. the state phone company has had all it's test gear made in yellow for about 50 years!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 19, 2018, 12:23:08 pm
Time to break out a C-note.  Bidders could almost buy one of Dave's rebranded Brymen BM235.  They must really want to save this old 189 from total destruction.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 19, 2018, 01:44:48 pm
Maybe they want to scavange parts to a another one :p or are very skilled repaired people.

The brymen BM235 is way better than the uni-t 61b, even it has less resolution. I believe someone sugested a rotary swiych 50k cycle to this brymen.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 19, 2018, 02:03:00 pm
Unless the seller shared an internal picture of the meter and it looks fine, I suspect the bidders may be unalerted of the potential pitfalls. I wonder if we will soon see a thread here about repairing a 189... :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 19, 2018, 03:16:17 pm
malagas_on_fire could be right.  Just buying it for parts.  It says not working, parts could be missing..... All pretty clear.  I would just bid what the parts are worth.  The case really does not look too bad.  Maybe a chip in the lens.   

When my friend gave me his 189, I looked into replacing the lens.  I called Fluke service but there were no parts available.  The meter was just too old.  I ran into that with the Fluke 97 scope meters.    They can't service them forever although it seems a few of us wish they did.  Funny, no one wants an 18 year old uni-t.   :-DD

I don't remember anyone asking me to lifecycle that BM235.  I ran a couple of Brymens and they both held up really well.  Plus we have the fact that Brymen actually tests their stuff before it hits the market.  What a concept.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 19, 2018, 04:20:37 pm
They do cycle test indeed on that brymen's.

No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
   
I've seen the video where you test pocket meters and the uni-t stood better :P What about a lifecycle on that little switch? I've seen a new pocket meter aneng 302 which has EF, true rms on Voltlog channel .. and of course basic input protection...
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 19, 2018, 04:52:32 pm
it actually could be an idiot who thinks it may be just a loose connection and he can do a quick turn-around on it.

there are several youtube channels of such people,
buying stuff for more than they should, admitting they know FA about the product, then stripping them hoping to spot something obvious!!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 19, 2018, 05:08:08 pm
They do cycle test indeed on that brymen's.

No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
   
I've seen the video where you test pocket meters and the uni-t stood better :P What about a lifecycle on that little switch? I've seen a new pocket meter aneng 302 which has EF, true rms on Voltlog channel .. and of course basic input protection...


 :-DD :-DD :-DD   :-DD :-DD :-DD
I can see you are one of the UNI-T pocket meter believers!  You are not alone. 

I test with VERY low energy levels.  20J max.  It's nothing.  Now again, keep in mind that the energy available is NORMALLY not dissipated in the meter.  Where's it go?   It's dissipated internal to the generator in the coupling network.  It's not just a bank of caps and a switch like some people have posted.  These people are lost.   The only time a meter would dissipate anything is if it breaks down.    Obviously, some amount will be dissipated in the clamping network (assuming the meter has such a clamp) but this is not what I am referring to.  I'm basically describing a short.    This is when you get to see in some of Fluke's videos where the meters explode. 

****
Let me add also that people have posted how I am slowly damaging the MOVs and how running them at high voltages will degrade them with time.   Again, it's not the case.  Sure the MOVs will degrade but for fun I setup a long term test showing the currents through a meter as I pushed the input voltage far past the meter's rating.  People seem to think the MOVs take the direct hit, which in all of the meters I have looked at, that's certainly not the case.  The MOVs sit behind a series of resistors and PTCs which limits the current available to them.   When I mention above that some energy is dissipated in the clamp, this is divided across all of those components, not just the MOVs.  And when we consider most meters will use the standard 1K resistor in series with a 1.2K PTC and a 1.5KV MOV, not much is dissipated.  It won't suck down that 20J available.   

****

In my testing, when a meter does break down, there is not enough energy available to the meter to do much of anything.  Make a few sparks, maybe blow apart a capacitor or an IC at best.

So we have a UNI-T that does not have near enough clearances and breaks down.   The generator does not provide enough energy to do anything more than make a small spark.  The breakdown voltage is low enough that the meter is basically undamaged.   Now, IMO, that it not a good thing.   The UT90A is like that and its why it continues to stay in my box of tricks.   If my generator had more energy, these meters would ... well.. I guess I'm not sure what would happen but I would like to see it, on the other side of a safety glass case. 

I'm sure you have seen my other generator that I refer to as a half cycle line simulator.  Unlike the fast, high voltage, low energy transient generators I normally use to run these test, this one creates a slow, low voltage, higher energy transient.   I've shown where this generator has no effect on the better class of meters.  Why?  Because they do not break down.  And without a low impedance  path, nothing is going to happen.   I don't use that generator to collect any data from the meters I look at.  There is no mention of it in the spreadsheet.  It's more just to give the viewers some idea of what could happen if a meter were to breakdown. 

In this video, I attempted to finish off the UNI-T UT90A with it.  Again the poorly designed layout saves the meter's electronics.    Don't mistake this for being a robust meter.  It's not! 

https://youtu.be/VHZ5cQPGo64?t=484

You can see, I normally run this test with the meters set to their highest AC voltage mode.  Here's the free HF meter.  Again, if this meter had not broke down, nothing would have happened. 
https://youtu.be/GHWb0kjrIY0?t=72

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 19, 2018, 05:08:49 pm
Whatever is the case we will soon now on a youtube channel or here :P

Maybe it ill become triple the price after that, since is a relic.  :-DD


Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 19, 2018, 06:32:08 pm
They do cycle test indeed on that brymen's.

No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
Despite your meter is probably a fine meter that does its job well, being manual range takes it back 20 years more (at least) - I have a UT54 that is in the same obsolete boat.

A 20 year old DMM from Fluke still has respectable specifications and is full autorange. Depending on where you live, the used market now presents a much wider range of good quality technology of yore, especially if it offers certain brands such as Fluke, Tektronix and others that still carry a lot of value over the years.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 19, 2018, 09:29:38 pm
Keep in mind that i'm not favouring uni-t by any means or have some preference of this brand. and back then it was affordable.  I have a pocket meter uni-t 120c and i do believe in it's specs , its price and a hard case.



My manual range 50b had a lot of luck . It is a obsolete model and has been now replaced with a Brymen BM235 ,  but it is still usable, accurate at least it's digits are better readable than aneng's. No doubt about the fluke's since they seem to never get too old.

It is very common here Uni-t, Fluke, Amprobe, Tektronix, on local stores. Agilent it came here too by online knowledge.

So my point is to check the price, functions, reviews and tests now when purchase something new to get the best value for the money.
Title: Re: Handheld meter electrical robustness testing.
Post by: Towger on August 20, 2018, 08:43:02 am
What about doing a robustness test on a fluke tester or voltage detector?

fluke 1651b test meter  https://ebay.us/pPhBFu

There is always a steady supply (eBay.co.uk) of faulty units and a number of people/companies making a living repairing them.  So it appears not to take much to damage one. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 20, 2018, 02:08:59 pm
Thanks again for the information.

In addtion to the opinion on the meters, when refering to tests, also mention the ones performed by joeqsmith, which gives an idea off the robustness related to DMM.

If people  think that is just capacitor because they see a exponetial decay on the waveform, well ... ask them for  a test JIG and data or just let them read the FAQ. The breakdown voltage and the high speed pulse may pass through less designed protection and hit the IC  even it's low energy, is enought to damage it.



Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 20, 2018, 02:48:03 pm
Keep in mind that i'm not favouring uni-t by any means or have some preference of this brand. and back then it was affordable.  I have a pocket meter uni-t 120c and i do believe in it's specs , its price and a hard case.

My manual range 50b had a lot of luck . It is a obsolete model and has been now replaced with a Brymen BM235 ,  but it is still usable, accurate at least it's digits are better readable than aneng's.
I didn't mean to imply that you were a fanboy; sorry. I just wanted to share the same story of a meter still perfectly usable but totally deprived of value... :)

One thing I like about these meters is, as you pointed out, the large digits on its LCD display.

No doubt about the fluke's since they seem to never get too old.
They really age very well; since they are very durable, the main caveat is that there are many terribly battered Flukes on eBay.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 20, 2018, 05:04:28 pm
The breakdown voltage and the high speed pulse may pass through less designed protection and hit the IC  even it's low energy, is enought to damage it.

The gas grill ignitor is a good example of this.   The new gun can output about 15 Amps in under a ns. I compare the grill ignitor against the IEC standards and its hardly worth running it's so low.  I get far worse pokes touching the door knobs in my house during the dry winter months  Yet many of the UNI-T  products I have looked at were damaged by it.   I show why the UT61E is so easily damaged which is a bit different than the problem I see with the UT181. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Vtile on August 20, 2018, 05:23:23 pm
Have you run any of those low end differential probes everyone is raving about through your test. The results might be interesting.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 20, 2018, 08:40:46 pm
https://www.youtube.com/watch?v=9M_OX-O9JKk (https://www.youtube.com/watch?v=9M_OX-O9JKk)

KREOSAN use a taser to impose a high voltage transient on 220VAC mains, and an arc starts "somewhere". Once an arc is established, mains high current flows until I think it extinguishs at next zero-cross, if there is no inductance/capacitance/carbon to sustain it.

Relevance to robustness testing- there's no CDN here so the transient generator's energy alone is not all a multimeter would see? I think the UNI-T UT90A would not have a nice little arc.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 20, 2018, 09:35:31 pm
Have you run any of those low end differential probes everyone is raving about through your test. The results might be interesting.
For the most part, I've only ran the meters that are on the list.   Maybe a few fuses and lightbulbs.  If you don't see a video of it, chances are I have not ran it.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 20, 2018, 11:07:35 pm
KREOSAN use a taser to impose a high voltage transient on 220VAC mains, and an arc starts "somewhere". Once an arc is established, mains high current flows until I think it extinguishs at next zero-cross, if there is no inductance/capacitance/carbon to sustain it.

Relevance to robustness testing- there's no CDN here so the transient generator's energy alone is not all a multimeter would see? I think the UNI-T UT90A would not have a nice little arc.
I am not sure what you are asking.  When I run these tests, I am not superimposing the transients on the AC mains, so there is no need for the CDN.  If you are referring to the stun gun as the transient generator and asking if the meter sees another source.  Then sure.  The mains.   Even with the CDN, it will still see the mains. 

I was not sure if your first part was asking a question or not.  Certainly you can sustain an arc between zero crossings.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 20, 2018, 11:33:31 pm
Don't worry it's just ESD  :P  :-DD

https://www.youtube.com/watch?time_continue=85&v=RtlYi1yLTVQ (https://www.youtube.com/watch?time_continue=85&v=RtlYi1yLTVQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: ProBang2 on August 20, 2018, 11:58:03 pm
Just for interest:

Uni-T seems to have beefed up the input protection on their UT139E and UT139S.
Isolation slots, more diode clamps and PTC´s.
Still rated with CAT III 600V (as the 139A/B/C). Independend certified by Intertek.
Maybe the 139E/S would survive the grill ignitor...
And, I must admit, the display of the 139E looks very nice.
(Somehow are bad displays never an issue of newer Uni-T multimeters...)
 
https://www.youtube.com/watch?v=1CwREOA9RSg&feature=youtu.be&t=19m43s (https://www.youtube.com/watch?v=1CwREOA9RSg&feature=youtu.be&t=19m43s)

I can´t resist the assumption: Someone from Uni-T observes this thread...
IMO: They have done very much right. At the first glance, there is nothing obvious to me that is wrong.
And they make progress with every new model. But: I am not an expert...

Therefor I am curious: What is the first impression to the "Master of Sparks and Lightning" himself?
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 21, 2018, 12:11:34 am
Maybe they will roll out a new UT181B.  I would make an exception for that meter and run one more UNI-T. 
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 21, 2018, 01:20:09 am
Consider making a mains-voltage measurement and a transient starts an arc within the multimeter - either in a controlled place (inside a GDT) or between shoddy clearances.

Once an arc starts, the transient dissipates quickly but behind it is more (long term) energy, from mains.
In an arc flash incident, this is what causes the heat, burns, injury.

I realized using only GDT's for multimeter protection, without series MOV's, is actually terribly dangerous.
It can survive transient (only) testing, but surely blow up when mains follows through on the arc.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 21, 2018, 02:01:21 am
Consider making a mains-voltage measurement and a transient starts an arc within the multimeter - either in a controlled place (inside a GDT) or between shoddy clearances.

Once an arc starts, the transient dissipates quickly but behind it is more (long term) energy, from mains.
In an arc flash incident, this is what causes the heat, burns, injury.

I realized using only GDT's for multimeter protection, without series MOV's, is actually terribly dangerous.
It can survive transient (only) testing, but surely blow up when mains follows through on the arc.
This is not true with every meter I have looked at that used GDTs.   The GDTs like the MOVs sit behind a network of PTCs and surge rates resistors.   It's not like they would put a GDT or MOV right across the inputs to the meter with nothing to limit the current.    Of course, there is one in every crowd.  Someone here actually had a meter that was like this!  But I doubt you will find a meter like this from a reputable company. 

The problem with the internet is so many people presenting things as facts with no data to back them up.   If you feel meters that use GDTs without a series MOV are terribly dangerous, provide some data.


In the meantime,  my vintage Fluke 189 of unknown origins takes to the transient generator.   

https://youtu.be/fHIPGIyLJ3M
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on August 21, 2018, 06:46:46 am
Maybe this is a Joe protection:

(http://lygte-info.dk/pic/UNI-T/UT125C/sparkgab.jpg)

It is found in a UNI-T UT125C and there is a fuse in series with it.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 21, 2018, 10:55:08 am
Good luck for the Fluke 189 . A new variant of the UNI-T 181? Humm maybe they also had review the board layout to supress the ESD fragility on the 3.3V switching internal PSU.

I think uni-t aims for the entry level for newer to electrical / electronics in controlled enviroments, but the uni-t 181A/B it should be beyound that due to it's price range. Ask them for a test :P



Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 21, 2018, 12:18:45 pm
it's possible that if you speak to the right person an UniTrend they may support you with free meters.
it would be worth it to them to both know what needs to be fixed, and to get good reviews to people.

they are watching and learning, look at the fuses & stuff in the newer meters - better than the 20mm glass  crap in the early stuff.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 21, 2018, 12:49:57 pm
They are watching and learning, look at the fuses & stuff in the newer meters - better than the 20mm glass  crap in the early stuff.

I'm not sure they learned that from joe's videos.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 21, 2018, 01:44:02 pm
I think uni-t aims for the entry level for newer to electrical / electronics in controlled enviroments, but the uni-t 181A/B it should be beyound that due to it's price range. Ask them for a test :P
The UT181 is categorized by them as "Industrial True RMS Multimeters":
http://www.uni-trend.com/productslist.aspx?IntroCateId=1024&ProductsCateID=1024&BaseInfoCateId=1024&cateid=1024&ViewCateID=1024 (http://www.uni-trend.com/productslist.aspx?IntroCateId=1024&ProductsCateID=1024&BaseInfoCateId=1024&cateid=1024&ViewCateID=1024)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 21, 2018, 06:58:26 pm
I think uni-t aims for the entry level for newer to electrical / electronics in controlled enviroments, but the uni-t 181A/B it should be beyound that due to it's price range. Ask them for a test :P
The UT181 is categorized by them as "Industrial True RMS Multimeters":
http://www.uni-trend.com/productslist.aspx?IntroCateId=1024&ProductsCateID=1024&BaseInfoCateId=1024&cateid=1024&ViewCateID=1024 (http://www.uni-trend.com/productslist.aspx?IntroCateId=1024&ProductsCateID=1024&BaseInfoCateId=1024&cateid=1024&ViewCateID=1024)

Yeah that's another issue too and the box also has a electrial board design . but they skipped the IEC related to ESD testing back when joeqsmith tested it.

Their website has some errors, for example the uni-t 204A clamp meter has a MAX mode in the specs section but in reallity is REL mode :P

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 22, 2018, 01:21:00 am
it's possible that if you speak to the right person an UniTrend they may support you with free meters.
it would be worth it to them to both know what needs to be fixed, and to get good reviews to people.

they are watching and learning, look at the fuses & stuff in the newer meters - better than the 20mm glass  crap in the early stuff.

At the very end of the video, I show the test running real time.  That's just five transients.  The 189 has ACV, ACmV, DCV, DCmV, Ohms, Capacitance and temperature modes that I run through.  So 7 times how ever long that 5 transients took.  Then I run + and -, so multiply by 2.   That's just one voltage level.   The point to all that is even if the meters are free, the time is not.   

Some time ago, someone at UNI-T did reach out to me.  I think they had a new meter that had the auto dimming back light that they were offering to me to look at.  I would be fine with that except I wanted to make it very clear to them what I do on channel and if they sent me the meter, I would run it like any other meter and document the results.   They never responded and I can't say I blame them.   To date, only Brymen has been so bold to stand behind their products.   

When you think about the other brands that have held up so well,  they could have some good free advertising but the channel is small and they may see no value in it.  I'm fine with it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 22, 2018, 01:30:18 am
I think uni-t aims for the entry level for newer to electrical / electronics in controlled enviroments, but the uni-t 181A/B it should be beyound that due to it's price range. Ask them for a test :P
The UT181 is categorized by them as "Industrial True RMS Multimeters":

That's what Gossen calls the Ultra as well, while testing at 1V/meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on August 22, 2018, 07:04:10 am
The UT181 is categorized by them as "Industrial True RMS Multimeters":

Does anybody still believe them?

Show us the UL certificates, etc.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 22, 2018, 12:28:47 pm
Yes, not for this particular case... Or for most other cases, although the UT61 variants sold in Europe seem to be ETL listed.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 22, 2018, 02:15:37 pm
To be honest i bought one uni-t 204A at a local store to read current from solar panels or for higher loads in AC without breaking circuits.

It has ETL and Intertek logo, a good jaw, 3999 counts, temperature and some accuracy

My bad call was i thought it was true RMS acourding to the specs of this website : https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut204a (https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut204a)

After a while i found a post here that stated it was not true RMS and also have confirmed against the BM235 and aneng 8001  :palm: . Not the best deal but at least it has done it's work and payed itself.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 23, 2018, 12:43:57 am
The UT181 is categorized by them as "Industrial True RMS Multimeters":

Does anybody still believe them?

Show us the UL certificates, etc.
I hope all of the testing I have shown has not caused you to become so cynical.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 23, 2018, 02:45:48 am
the low just got lower.

check out the integrated "spark gap" on this brand new DT830!!!  :wtf:
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 23, 2018, 02:49:47 am
To be honest i bought one uni-t 204A at a local store to read current from solar panels or for higher loads in AC without breaking circuits.

It has ETL and Intertek logo, a good jaw, 3999 counts, temperature and some accuracy

do you know what chipset it uses?
we may be able to "improve" the specs with an eeprom hack.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 23, 2018, 08:12:11 am
The UT181 is categorized by them as "Industrial True RMS Multimeters":

Does anybody still believe them?

Show us the UL certificates, etc.
I hope all of the testing I have shown has not caused you to become so cynical.   :-DD

No worries. I rather have data and testing to have a better ideia of the value for the money, than buying a product that fails in a middle of a work. I have some uni-t's and they are good for learning purposes or CATII usage. But also consider other brands like brymen, amprobe, fluke.

But of course i got surprised when the ut 181a failed and Lol on the pocket meter
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 23, 2018, 08:16:05 am
To be honest i bought one uni-t 204A at a local store to read current from solar panels or for higher loads in AC without breaking circuits.

It has ETL and Intertek logo, a good jaw, 3999 counts, temperature and some accuracy

do you know what chipset it uses?
we may be able to "improve" the specs with an eeprom hack.

That would do a great idea but after warranty expires. I'll ask uni-t about the specs.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2018, 02:15:15 am
Replaced the supercap in the old Fluke 189 and tested a few different resistors for the lead detection circuit.  Then it was back to transient testing the old girl.   

https://youtu.be/8t8nkCbYJVc
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on August 26, 2018, 05:55:35 am
Resistors roasting on an open board... ♫

 ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: kcbrown on August 26, 2018, 06:42:31 am
why not blow one to hell, then re-list it on EvilBay?  >:D

"Fluke 189 for sale, barely used"

("accidentally" neglecting to mention that it had been "used" about 5 minutes before Joe's tests blew it to kingdom come)    :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 26, 2018, 12:28:43 pm
why not blow one to hell, then re-list it on EvilBay?  >:D

"Fluke 189 for sale, barely used"

("accidentally" neglecting to mention that it had been "used" about 5 minutes before Joe's tests blew it to kingdom come)    :-DD

"Fluke 189 for sale, calibrated, electrically test pass"

PS.: batteries not included :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2018, 05:03:48 pm
Resistors roasting on an open board... ♫

 ;D
The season is coming up. 

why not blow one to hell, then re-list it on EvilBay?  >:D

"Fluke 189 for sale, barely used"

("accidentally" neglecting to mention that it had been "used" about 5 minutes before Joe's tests blew it to kingdom come)    :-DD

"Fluke 189 for sale, calibrated, electrically test pass"

PS.: batteries not included :P

It seems like a pretty tough meter.  It may be 18ish years old but still outperforms most of the meters I have looked at.   

When I started all this testing, I wouldn't have given you a dollar for a Fluke meter.  My disdain for them ran pretty deep.  :-DD   But I am also data driven and can't deny that they have learned how to make very robust products over the years.   Hard to say is they are now on the down swing of that cycle. 

I've shown it's fairly easy to design a handheld that will survive some basic low energy transients.  I've seen a few people comment about how you can add a few dollars in parts are have a very robust product.    It does not always seem to be a cost problem.  I've looked at some fairly high priced meters that did not perform very well at all.   At some point, the engineers also need to know how to design robust products.   
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 26, 2018, 05:47:22 pm
It's very difficult engineering things for transients, as the outcome is destructive - something fails and everybody scratches their heads and guesses what went wrong.  It's like an airplane crash.

A Teseq is very expensive. $30K and even more for calibration and upkeep, another $6k for the H/W and F/W upgrades. For something rarely used and seen as a small regulatory hurdle, management doesn't want to put any money into it. Consider selling your transient generator ;)

You do a run and after the explosion, there is no high speed camera footage as to where the breakdown started.
It is quite a clown car for the junior engineers, who are terrified of using the transient generator and later stunned that they have no data or equation to reconsider.
Months go by and the product is late to market, pressure is on. The product has no budget dollars or room for bigger parts and clearances. I could go on and on.

It's mostly a problem of engineers not understanding the safety standards, the high costs with consulting UL/CSA over $400/hr, and the high costs of the test equipment, all to meet a few paragraphs in a safety standard- as the boss sees it.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 26, 2018, 06:00:33 pm
The flukes are really good and the one i used and like a lot was the 117. They have the formula ( component selection, board layout, rotary switch)to build a robust meter and it is appliable to various types of meters, even the little fluke 101.

Some of the brands take "gidelines" to design products that may meet the expected CAT without certification because that costs money. Here an ut61e Intertek / GS costs 82 Euros  or for more 20 euros you can order a brymen BM235 or a fluke 17B+ that has backlight, better fuses, input protection, rotary switch but of course less resolution and no PC connection.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2018, 06:43:37 pm
It's very difficult engineering things for transients, as the outcome is destructive - something fails and everybody scratches their heads and guesses what went wrong.  It's like an airplane crash.

A Teseq is very expensive. $30K and even more for calibration and upkeep, another $6k for the H/W and F/W upgrades. For something rarely used and seen as a small regulatory hurdle, management doesn't want to put any money into it. Consider selling your transient generator ;)

You do a run and after the explosion, there is no high speed camera footage as to where the breakdown started.
It is quite a clown car for the junior engineers, who are terrified of using the transient generator and later stunned that they have no data or equation to reconsider.
Months go by and the product is late to market, pressure is on. The product has no budget dollars or room for bigger parts and clearances. I could go on and on.

It's mostly a problem of engineers not understanding the safety standards, the high costs with consulting UL/CSA over $400/hr, and the high costs of the test equipment, all to meet a few paragraphs in a safety standard- as the boss sees it.

The stories I could tell......   :-DD :-DD :-DD

My generators are toys compared with an actual combo generator.   I've thought about making a video where I show some very simple circuits that a beginning hobbyist may put together that could possibly damage their meter.    Just very low energy battery operated stuff.  The kids already play with the MOTs and do a good job cooking their meters and sometimes their bodies so it's a bit hard to complete with.     
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 26, 2018, 07:13:07 pm
That's a good start with MOT since there is scavanging components in big scale and buying cheap meters is a good mix for testing it's robustness as  almost one time operation.

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 26, 2018, 08:09:13 pm
That's a good start with MOT since there is scavanging components in big scale and buying cheap meters is a good mix for testing it's robustness as  almost one time operation.


Well there is always the good old cell phone charger bricks with 6VA transformers 230V / 6V in back to back configuration or a brand new 12VA 230V / 12V for the newer to start on higher voltages :P

Battery operated? A flyswatter for example
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2018, 09:41:02 pm
That's a good start with MOT since there is scavanging components in big scale and buying cheap meters is a good mix for testing it's robustness as  almost one time operation.

Well there is always the good old cell phone charger bricks with 6VA transformers 230V / 6V in back to back configuration or a brand new 12VA 230V / 12V for the newer to start on higher voltages :P

Battery operated? A flyswatter for example

Yes, something along those lines.  Maybe even include the flyswatter.   A member here (Scott) had ran some flyswatter tests.   I'm not sure if he damaged a meter with one or not.    That's actually why I bought one to have some fun with. 

The MOT can apparently do a fair job of cooking a human as at least one 15 year old kid from Ohio found out.   A pretty high price paid for that bit of education.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 26, 2018, 10:03:49 pm
Wow... If the fault description is accurate with what actually happened in this thread (https://www.eevblog.com/forum/repair/ut71e-dead-or-something-else!/msg1776719/?topicseen#msg1776719), I propose to add a new test to your mix: EPV (Extremely Puny Voltage) breakdown test.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 26, 2018, 11:09:27 pm
Wow... If the fault description is accurate with what actually happened in this thread (https://www.eevblog.com/forum/repair/ut71e-dead-or-something-else!/msg1776719/?topicseen#msg1776719), I propose to add a new test to your mix: EPV (Extremely Puny Voltage) breakdown test.

Keep in mind that's a boost converter that they are using in place of the standard batteries.  The battery input on any handheld may not be protected that well.  At least, that is what I understood them to be doing when it was damaged. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 27, 2018, 12:38:57 am
Wow... If the fault description is accurate with what actually happened in this thread (https://www.eevblog.com/forum/repair/ut71e-dead-or-something-else!/msg1776719/?topicseen#msg1776719), I propose to add a new test to your mix: EPV (Extremely Puny Voltage) breakdown test.

Keep in mind that's a boost converter that they are using in place of the standard batteries.  The battery input on any handheld may not be protected that well.  At least, that is what I understood them to be doing when it was damaged.
Actually, you are correct; I read as being applied on the input, but it was a problem with VCC. That would certainly damage things.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2018, 10:46:27 pm
Hammer vs the Fluke 189.  Hammer wins.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 27, 2018, 11:34:19 pm
Hammer vs the Fluke 189.  Hammer wins.
What the...?!?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2018, 11:44:16 pm
It was way beyond wet sanding.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on August 28, 2018, 12:20:29 am
It was way beyond wet sanding.   :-DD

Yes, but you could have tried the flame polishing idea? Perfect sacrificial test piece.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 28, 2018, 12:38:03 am
It was badly cracked.  Now if you were recommending to just burn the whole meter to a crisp, I may be onboard.  Poor meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 28, 2018, 02:08:01 am
Cut some Lexsand on a bandsaw and hand cut the lips into it.  Needs some glue
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 28, 2018, 08:41:13 am
Well the hammer is the good solution for things that have no solution just as for the intermitent USB cables with cut pliers on the plugs.
Nice Job on the new lexan and glue should be ABS compliant maybe...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 28, 2018, 11:27:08 am
At least the display can be read now.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on August 28, 2018, 02:45:09 pm
those all look pretty mint, i thought the name was screenprinted on the back of the acrylic window??
Title: Re: Handheld meter electrical robustness testing.
Post by: true on August 31, 2018, 06:08:12 am
A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.

What happens:
- Auto mode freaks out and doesn't work (a short shows an unstable high resistance for example)
- Short detect mode shows shorted
- EF (power stick) mode works
- I can't remember what Low-Z volts does
- Hi-Z voltage works
- Diode mode acts like a short
- High ohms varies from not working to usually sounding the "shorted" beeper; IIRC high ohms will not give a stable reading
- Haven't tested current

What causes this?

The only similar thing I could find was a dying battery.

I purchased a new unit after my PM55A had failed, only to find a PM55 I gave to a friend also failed. I tested a PM55 I had and it too had failed. The replacement? Well, it tested good (testing 5V in auto mode, and shorting probes, that's it...); after a month when I went to use it to test a low voltage DC circuit again, it showed low battery ... and sure enough it failed too.

I'd like to fix them but have no idea where to start or what could have failed.
Title: Re: Handheld meter electrical robustness testing.
Post by: retiredcaps on August 31, 2018, 06:31:48 am
A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.
Amprobe PM55A is a Brymen BM27s rebadged.

So you are reporting that these ALL fail?  And after you replace the CR2032 battery, it still doesn't work?
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 31, 2018, 07:07:34 am
Brymen BM27s has HC4053 mux, it might be pooched, or the Cosmo W414S mosfet AC SSR, dual SPST. One for Low-Z and not sure what the other switch does.
I wonder if it would survive the BBQ lighter spark test.

good PCB pics at bottom of review: https://lygte-info.dk/review/DMMBrymen BM27s UK.html (https://lygte-info.dk/review/DMMBrymen BM27s UK.html)
Title: Re: Handheld meter electrical robustness testing.
Post by: true on August 31, 2018, 07:18:14 am
A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.
Amprobe PM55A is a Brymen BM27s rebadged.

So you are reporting that these ALL fail?  And after you replace the CR2032 battery, it still doesn't work?

Yes, all have failed in the same manner, and of course I have tried new CR2032 in each of them.
Title: Re: Handheld meter electrical robustness testing.
Post by: joseph nicholas on August 31, 2018, 10:38:26 am
Have you tried checking that the CR 2032 battery is giving its full rated voltage?  I ordered 10 CR 2032 batteries on ebay and all were giving less that 3 volts, half were completely dead. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 31, 2018, 11:48:00 am
Applying 1KVDC to various surface mount resistors 

https://youtu.be/8Zl2HJ5qo_4
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 31, 2018, 01:11:59 pm
Have you tried checking that the CR 2032 battery is giving its full rated voltage?  I ordered 10 CR 2032 batteries on ebay and all were giving less that 3 volts, half were completely dead.

Those cheapo batteries most certanly have pass the expiring date. Carefull when buying these batteries to inspect this in the description.

The energizer , duracell , maxell do well. Carefull in current measurement that may deplete more fast the battery .

Example .:

https://cdn-shop.adafruit.com/datasheets/maxell_cr2032_datasheet.pdf

Title: Re: Handheld meter electrical robustness testing.
Post by: true on August 31, 2018, 01:21:17 pm
Have you tried checking that the CR 2032 battery is giving its full rated voltage?
Of course I checked this...otherwise I would not be posting. The replacement batteries have all been fine, showing correct voltage with a resistor load, the screen on the meter has sharp contrast and the low battery indicator is not lit.

I believe there is some fault but do not know what has caused it. I can only say that it has happened on all 4 meters that I have access to, and the meter I bought to hopefully troubleshoot this failed before I even really got to use it.

Right now I am hoping it is the mux or SSR. And it may not be low battery causing them to fail, but that's the only thing in common between all of them, is that they failed when the low battery indicator was on.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on August 31, 2018, 06:02:48 pm
Are you doing harsh work with these meters or is this some unknown weakness they have?
You could try go up to 3.3V for power to see if it's a battery issue. But the defunct ranges seem to point out the mux, as a guess.

I checked and the Brymen 27s has legit 61010 UL certification, so it should not be fragile for ESD.
Unless the plastic shield inadvertently allows arcs between internal nodes on the PCB...

Primary lithium batteries have passivation, so a new battery can measure low V and after some drain the cell voltage rises. Not so much with lithium/manganese dioxide coin cells, but a big issue with lithium-thionyl chloride cells.


Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on August 31, 2018, 09:03:19 pm
Wow that's a huge test and a bunch of meters . Are you expecting to check if the series resistor implementation is possible to replicate in the Fluke 189 or other designs for high voltage?

Title: Re: Handheld meter electrical robustness testing.
Post by: true on September 01, 2018, 04:59:50 am
Are you doing harsh work with these meters or is this some unknown weakness they have?
If I was I would have mentioned it. As I said, my replacement was used twice to measure a simple 5VDC circuit. Between the first and second time - as in, before it was used the second time, it failed. The other meters are also not abused in any way, usually used for low voltage DC circuits and simple tests.

You could try go up to 3.3V for power to see if it's a battery issue. But the defunct ranges seem to point out the mux, as a guess.

I checked and the Brymen 27s has legit 61010 UL certification, so it should not be fragile for ESD.
Unless the plastic shield inadvertently allows arcs between internal nodes on the PCB...
I'm not thinking it's ESD though it could be possible. I noticed this when my meter crapped out after it had a low battery. I ordered a replacement, and my friend said the same thing. I checked my old PM55 which worked last time, and sure enough, same thing. My replacement PM55A showed good voltage on battery, but next time I went to use it, low battery...checked ohms range, sure enough, same fault. Replaced battery with fresh, tested cell, fault still exists.

Not to blame the low battery, but that, and non-harsh use, are the only similarities. But perhaps the zip-up case they come in can generate enough ESD to blow something up?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 01, 2018, 03:31:14 pm
A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.

What happens:
- Auto mode freaks out and doesn't work (a short shows an unstable high resistance for example)
- Short detect mode shows shorted
- EF (power stick) mode works
- I can't remember what Low-Z volts does
- Hi-Z voltage works
- Diode mode acts like a short
- High ohms varies from not working to usually sounding the "shorted" beeper; IIRC high ohms will not give a stable reading
- Haven't tested current

What causes this?

The only similar thing I could find was a dying battery.

I purchased a new unit after my PM55A had failed, only to find a PM55 I gave to a friend also failed. I tested a PM55 I had and it too had failed. The replacement? Well, it tested good (testing 5V in auto mode, and shorting probes, that's it...); after a month when I went to use it to test a low voltage DC circuit again, it showed low battery ... and sure enough it failed too.

I'd like to fix them but have no idea where to start or what could have failed.
I read through your posts.  First, I am not understanding why you would have posted in this thread of all places vs starting a new one.  There is even a repair section that had you used, may have brought more attention/help.   Is there some reason you keep buying the same meter with the same problem?  There is a word for that.  Then again, I have bought more than one of the same meter just to damage them so, welcome to the the club. 

Have you tried to contact Brymen directly about what you are seeing?  If so, what was their response?   What about contacting AMPROBE or the distributor you procured them from? 

I have never looked at this specific meter and really can't offer any suggestions on what may have failed and why. 
Title: Re: Handheld meter electrical robustness testing.
Post by: MiroS on September 04, 2018, 01:39:20 pm
> Is there some reason you keep buying the same meter with the same problem?

I think Joe is doing a great work we are or will apprciate.  See 87V two tests - two results ...
For sceptics - see autopsy of FK87V. Joe tests are very delicate I would say.


Title: Re: Handheld meter electrical robustness testing.
Post by: true on September 04, 2018, 05:28:36 pm
I read through your posts.  First, I am not understanding why you would have posted in this thread of all places vs starting a new one. There is even a repair section that had you used, may have brought more attention/help.
Maybe I should? I don't have much time to go over repair on this right now, but plan to post when I do have time, and wanted to make mention where it may be noticed. If this thing fails so easily it may be worth testing, especially if it ends up the failure was ESD induced. Maybe someone is willing to do some tests if they have one that hasn't yet died - that's why I posted here for now. Still maybe not relevant enough, I don't know.

Is there some reason you keep buying the same meter with the same problem?
Because I was not aware of the problem when I ordered my replacement.

I purchased my replacement because my unit was dead and I could not find anyone with similar problems. The order was done before I learned that the Meterman-branded unit I gave my friend failed - because, well, he doesn't share all his life details with me. I made mention I ordered a replacement and then he told me his failed. I went and checked my other meter at the house and sure enough, it had failed.

There is a word for that.
Right.

Then again, I have bought more than one of the same meter just to damage them so, welcome to the the club.
I bought these to use them. Before they failed, I quite liked them.

Have you tried to contact Brymen directly about what you are seeing?  If so, what was their response?   What about contacting AMPROBE or the distributor you procured them from?
Until this latest one, all were out of warranty - Meterman has long since been bought out and Amprobe only has short warranties. I've reached out to Amprobe with no response so I will try again. Ultimately they won't be interested in telling me what the fault is anyway, thus posting here.  But not in a good enough way / its own thread I guess. And if they repair it, I don't know that it won't fail again.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on September 04, 2018, 05:47:36 pm
A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.

What happens:
- Auto mode freaks out and doesn't work (a short shows an unstable high resistance for example)
- Short detect mode shows shorted
- EF (power stick) mode works
- I can't remember what Low-Z volts does
- Hi-Z voltage works
- Diode mode acts like a short
- High ohms varies from not working to usually sounding the "shorted" beeper; IIRC high ohms will not give a stable reading
- Haven't tested current

What causes this?

The only similar thing I could find was a dying battery.

I purchased a new unit after my PM55A had failed, only to find a PM55 I gave to a friend also failed. I tested a PM55 I had and it too had failed. The replacement? Well, it tested good (testing 5V in auto mode, and shorting probes, that's it...); after a month when I went to use it to test a low voltage DC circuit again, it showed low battery ... and sure enough it failed too.

I'd like to fix them but have no idea where to start or what could have failed.

I agree with Joe that starting a new thread with a title containing the keywords "Meterman Amprobe PM55 Problems" would probably have gained more attention than tagging on the end of this thread.

However, the symptoms you list above make me wonder if something is wrong with the rotary selection switch. Something could have gone wrong with the contacts. This may happen with low cost meters due to oxidation causing poor contact or mechanical wear producing metal dust and debris causing shorts.

A good start to investigation might be to disassemble the meter and closely examine the range selector mechanism.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 04, 2018, 05:51:03 pm
Based on your initial post, I assumed your goal was to repair them.  I would ask in the repair section.  If your goal was to attempt to have me run one, it's an odd way to go about it.  Most people would simply ask. 

If it is a Brymen product as suggested, they would be the first company I would contact.   The only reason I would reach out to AMPROBE or the distributor would be to try and have them covered. 

It looks like you have had them for 5 years or so.  I certainly would have no way of knowing how they were treated during this time.   It appears they are still available so it would be possible to see how they fair against the other meters I have looked at. 
 
https://www.eevblog.com/forum/testgear/review-uni-t-ut136b-tired-of-the-multimeter-snobs-a-very-nice-budget-meter (https://www.eevblog.com/forum/testgear/review-uni-t-ut136b-tired-of-the-multimeter-snobs-a-very-nice-budget-meter)!/msg242028/#msg242028

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 04, 2018, 05:54:28 pm
> Is there some reason you keep buying the same meter with the same problem?

I think Joe is doing a great work we are or will apprciate.  See 87V two tests - two results ...
For sceptics - see autopsy of FK87V. Joe tests are very delicate I would say.

ROFLMAO!  Very nice!  Is there a story that goes with these pictures? 
Title: Re: Handheld meter electrical robustness testing.
Post by: MiroS on September 06, 2018, 09:26:57 am
ROFLMAO!  Very nice!  Is there a story that goes with these pictures?
[/quote]

Unfortunately not mine, no idea how this has happened.  Anyway prvoked my head to some questions:
- Majority of damage is caused by this fused resistor, it fired PCB, internal plastic protection  and even the case. Hmm... this looks like this resistor was too slow to cut connection and made huge explosion and fire.  Shuould  fused resisitor really explode? Is plastic protection a correct protection from fire?
- PTC was compeltely melted and changed to cloud of smoke. Maybe it shuld be heatshrinked to react faster on overrload (heat cumuates faster when PTC is shrinked?)
- MOVs exploded, but PCB trace to MOVs surrived intact, hmmm ... why?
- None of fuses exploded or broke connection, hmm ...all were just fine. No they were not repalced after damage, all were nicely smoked.



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 06, 2018, 10:56:27 am
Unfortunately not mine, no idea how this has happened.  Anyway prvoked my head to some questions:
That's too bad.  Knowing about the fuses,  suggests you may have met the owner.   

Quote
- Majority of damage is caused by this fused resistor, it fired PCB, internal plastic protection  and even the case. Hmm... this looks like this resistor was too slow to cut connection and made huge explosion and fire.  Shuould  fused resisitor really explode? Is plastic protection a correct protection from fire?

Even with my small transients and the camera running at close to 1ms frame rates, it's no where fast enough to capture an event like this.  I see a lot of people post about the input protection circuit is for safety.  As you can see from the picture, the case plays a big part.   

If you exceed the design limits of any component, I am guessing you could see it fail in the same manor.   PhotonicInduction made a few videos where he placed some HRC fuses across a large high voltage capacitor and was able to get them to rupture.   These were 10KA+ break currents.  So even a safety fuse will have it's limits.  :-DD   That was a very interesting channel to watch.  Nothing I would ever attempt at home. 

Quote
- PTC was compeltely melted and changed to cloud of smoke. Maybe it shuld be heatshrinked to react faster on overrload (heat cumuates faster when PTC is shrinked?)

I doubt heat shrunk tube would do much in this case.   I've seen it used a fair amount on the smaller PTCs but not the larger ones.   During my tests, I've damaged a fair number of PTCs in low end meters.  They often use 5mm parts which don't always hold up very well.   

Quote
- MOVs exploded, but PCB trace to MOVs surrived intact, hmmm ... why?
Higher resistance, more power dissipated?   

Quote
- None of fuses exploded or broke connection, hmm ...all were just fine. No they were not repalced after damage, all were nicely smoked.
Why would the fuses be effected.  It's obvious that what ever happened, it was on the voltage circuit of the meter, not the current. 

I would say in this case, trying to make a meter survive what ever happened is not solving the root problem.  With so little damage done to the meter, I doubt the person was harmed and may not have learned anything from it.   Next time, they may not be so lucky.     
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 06, 2018, 11:48:28 am
Wow that is  a toasted meter .

Did some put DC voltage , MOT on that meter? Maybe a higher spike.  this looks like a result of the half cycle simulator but with even more energy.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 06, 2018, 12:01:26 pm
Wow that is  a toasted meter .

Did some put DC voltage , MOT on that meter? Maybe a higher spike.  this looks like a result of the half cycle simulator but with even more energy.

There's not enough damage to where I would have guessed it was on a HV mains bus.  I could not do anywhere near this damage to a Fluke with the half cycle generator.  I've shown it attached to a few of the better meters.  Nothing happens.  The voltage is too low.  I'm going with a kid and their MOT.  :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 07, 2018, 12:08:37 am
well the worst meters got in bad shape with the half cycle simulator and then not a lot of energy to  upset fluke, brymen.

So if a Fluke got to that point that's should be called the how to not use a Fluke ... for repair Microwave  HV sources ... aka MOT... or maybe a CRT tv or monitor...

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 07, 2018, 12:54:58 am
A meter would need to break (have a low impedance path) for the half cycle simulator to do anything.   The Fluke's normally don't break down so the energy just dissipates inside the generators.  There always the same amount of energy available, but if a meter is an open circuit it won't present much of a load.   

The CRT is a good one.  I liked this guys video.  When I asked about what the cause was they explained that it was a HV supply for the display.  You can't blame Fluke, or any other meter for not holding up to this abuse.   
https://www.youtube.com/watch?v=DUwkuM3blsk (https://www.youtube.com/watch?v=DUwkuM3blsk)
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on September 07, 2018, 10:06:51 am
i have seen a similar chared mess in a cheaper meter once.
some idiot thought it would be a good idea to diagnose an engine problem by metering the voltage at the spark plugs!  :palm:

i laughed my ass off when he told me how he killed his meter.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 07, 2018, 11:28:42 am
Yeah the fluke's are made to deal with that kind of stress, but man an engineer plug the meter to the CRT tube???? Thank that it was in a good technician able to repair the 189.

What a waste of bad usage on such a good meter. It is very easy to kill cheap meters with a flyswatter or a insulator tester with 5kV capability as they are available for selling.... Now damage a fluke in that manner is lack of responsability , knowledge of specs.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 08, 2018, 12:14:00 am
i have seen a similar chared mess in a cheaper meter once.
some idiot thought it would be a good idea to diagnose an engine problem by metering the voltage at the spark plugs!  :palm:

i laughed my ass off when he told me how he killed his meter.  :-DD

I would never have guessed a car ignition system would burn a board like this.   I tried a few early meters across my MSD with little effect.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on September 08, 2018, 09:11:56 am
constant stream of high current sparks from an oil-cooled transformer can do a lot of damage.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2018, 02:22:58 am
constant stream of high current sparks from an oil-cooled transformer can do a lot of damage.
Agree that any transformer that can put out high voltage and high current could do a lot of damage but my ignition coils don't put out a lot of current.  I could try to burn a meter down with one. 

****

I did show a neon sign transformer hooked up to a few early on.  That's a bit more current than I can get out of any of my ignition coils.   
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on September 09, 2018, 02:30:14 am
how are you driving the coil?
modern cars use capacitive discharge to give the coil a good kick.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 09, 2018, 02:37:40 am
how are you driving the coil?
modern cars use capacitive discharge to give the coil a good kick.
MSD racing ignition systems provide far more power than anything from 'consumer' automotive manufacturers.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on September 09, 2018, 02:44:55 am
Agree that any transformer that can put out high voltage and high current could do a lot of damage but my ignition coils don't put out a lot of current.  I could try to burn a meter down with one. 

Clearly we need to see a meter hooked up to the ~10 kV circuit on the high side of a mains distribution transformer. Though it would have to be a disposable meter as I think it would be completely vaporized in a fireball of epic proportions...
Title: Re: Handheld meter electrical robustness testing.
Post by: SeanB on September 09, 2018, 08:15:31 am
Agree that any transformer that can put out high voltage and high current could do a lot of damage but my ignition coils don't put out a lot of current.  I could try to burn a meter down with one. 

Clearly we need to see a meter hooked up to the ~10 kV circuit on the high side of a mains distribution transformer. Though it would have to be a disposable meter as I think it would be completely vaporized in a fireball of epic proportions...

Fluke 77 does survive that with the case intact, though the leads do become a lot shorter. Inside the case however there is a nice copper plate on the plastic inside, and the lower half under the display of the board is remarkably free from any traces, aside from where the components are soldered to the board. The fuses do not blow.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on September 09, 2018, 11:35:48 am
how are you driving the coil?
modern cars use capacitive discharge to give the coil a good kick.
MSD racing ignition systems provide far more power than anything from 'consumer' automotive manufacturers.
"systems", yes.
not just the coil - it's all about the drive circuit.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 09, 2018, 11:46:12 am
how are you driving the coil?
modern cars use capacitive discharge to give the coil a good kick.
MSD racing ignition systems provide far more power than anything from 'consumer' automotive manufacturers.
"systems", yes.
not just the coil - it's all about the drive circuit.
Joe knows and so do I. The last MSD CD drive unit I scoped was ~400V but as it was a bit older so nowhere near the Joules they make these days. Something like Methanol of top fuel with a bucket load of boost up its arse is pretty hard to light.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 09, 2018, 04:17:15 pm
Definitly from the video its quite  a big spark and supposelly the meter is automotive... very susceptible to the spark till reset point.  Imagine doing the same on the cheaper ones...
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on September 09, 2018, 05:32:19 pm
Clearly we need to see a meter hooked up to the ~10 kV circuit on the high side of a mains distribution transformer. Though it would have to be a disposable meter as I think it would be completely vaporized in a fireball of epic proportions...

What is the point here, of course the meter burns up and so does the person near it.
People have been killed connecting a Fluke 87 to 2.3kV MCC. Look at the Eddie Adams' Arc Flash Fatality Video.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 09, 2018, 07:16:48 pm
That is the result of following the design recommendations from the datasheets only or had a extra touch?

That will nuke a DMM out of orbit for sure... That is required for superbikes? That will ignite wihout any flaws and a lot of HP.

Many have been killed by MOT's , alongside the case of the boy who got killed with one mentioned by joeqsmith:

https://www.electronicproducts.com/Power_Products/AC_DC_Power_Supplies/Guy_takes_apart_microwave_oven_to_create_a_microwave_cannon_then_blows_stuff_up_with_it.aspx (https://www.electronicproducts.com/Power_Products/AC_DC_Power_Supplies/Guy_takes_apart_microwave_oven_to_create_a_microwave_cannon_then_blows_stuff_up_with_it.aspx)

https://www.woodworkingnetwork.com/news/woodworking-industry-news/death-prompts-ban-fractal-burning (https://www.woodworkingnetwork.com/news/woodworking-industry-news/death-prompts-ban-fractal-burning)


Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 09, 2018, 08:08:08 pm

Even with 30 PSIG of intake pressure, the gasoline will ignite fairly easily.  Compare my MC-4 with a magneto.  I wonder how many HP it takes... 
Once the compression ratio nears 200 PSI and flooded with methanol things get interesting. The only way we could confirm a dodgy ignition system was to scope its outputs into the coil packs. We had some strong clues from the logging to work with and we could see strong correlations between boost, RPM, EGT's and the TPS. My mate just wanted to biff the module as the coil packs had already been swapped out but the flat spots at high motor stress still remained. This was a 13B so there were only two channels of leading and trailing but the leading set have the most influence on engine performance so it could be managed with just a 2ch scope and was an easy find with one channel being ~100V down so insufficient puff to light the plugs at full boost.
Had them chasing their tails for a bit until the electronics geek neighbor arrived and sorted them out.  :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2018, 09:44:41 pm
That is the result of following the design recommendations from the datasheets only or had a extra touch?

That will nuke a DMM out of orbit for sure... That is required for superbikes? That will ignite wihout any flaws and a lot of HP.

No extra black magic.  I just took the time to read the data sheets and then looked at how the meter was designed.  There was a pretty obvious flaw that the designers should have caught when they tested it. 

This ignition is really designed for drag racing.  My bikes are fairly low power and using gasoline.     

We had some strong clues from the logging to work with and we could see strong correlations between boost, RPM, EGT's and the TPS.
 
Collecting data is part of the fun..  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 09, 2018, 10:08:25 pm
We had some strong clues from the logging to work with and we could see strong correlations between boost, RPM, EGT's and the TPS.
 
Collecting data is part of the fun..  :-DD
:)
Only when you know how to interpret it and act on the info gained !  ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2018, 10:23:50 pm
It's been a while.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 09, 2018, 10:37:48 pm
Lloooolll here a idiot means a person who has ideas and the ideia was correcting the sentence  :P

I comment about the special touch because the videos on the uni-t 61e and uni-t 181A that became more robust with your magic :P.

No wonder how the drag racing has that "violent" startup.  They almost could fly off the road.

There must be some complex telemetry regarding the engine and it's different stages waiting to be processed .  :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 09, 2018, 10:54:00 pm
Lloooolll here a idiot means a person who has ideas and the ideia was correcting the sentence  :P

I comment about the special touch because the videos on the uni-t 61e and uni-t 181A that became more robust with your magic :P.

No wonder how the drag racing has that "violent" startup.  They almost could fly off the road.

There must be some complex telemetry regarding the engine and it's different stages waiting to be processed .  :-DMM
Not so much for the little guy as passes are so short so that all the data is logged and downloaded after a run.
The 'big time' guys will do it wirelessly to have it live and that gives them a timeline edge to make adjustments before the next run.
The stresses are phenomenal so many parameters are monitored now to provide the full picture of the many variables in getting consistently good runs.
It's a heap of fun to get involved in......addictive if you like.  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on September 09, 2018, 11:11:06 pm
We had some strong clues from the logging to work with and we could see strong correlations between boost, RPM, EGT's and the TPS.
 
Collecting data is part of the fun..  :-DD
:)
Only when you know how to interpret it and act on the info gained !  ;)
The two main things I learned the most about from logging was tuning the clutch and keeping things lubricated.  AFR maybe next.   
Guys here in NZ log EGT's only so not to turn their 'investment' into a grenade !  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2018, 11:33:53 pm
I have no one to send any live data to and just download after the fact.  I keep a database of all this data.

The stresses are phenomenal ...

...addictive if you like.  :)

Even with my bikes, I am amazed at how much stress some of the parts take.  I used to have a video showing the flex but YT flagged it for copyright.   Eventually I added more steel to the chassis to combat the flex as the bike was getting too difficult for me to ride.   Speed is addictive alright. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 09, 2018, 11:48:03 pm
Lloooolll here a idiot means a person who has ideas and the ideia was correcting the sentence  :P

I comment about the special touch because the videos on the uni-t 61e and uni-t 181A that became more robust with your magic :P.
I didn't do much transient testing with this particular meter as I knew it would not hold up very well.  It's really designed for low voltage automotive use but it could not even handle that environment.   No doubt I could improve this meter but my goal was to just understand why it was so sensitive and would reset, then correct it.   

Noise from that ignition is pretty harsh but as you could see that BM869s handled it very well.  Brymen knows how to make a meter.   One day I will put the 121GW near it.   Even after changing the meter, it still did not perform as well as Brymen's little automotive meter.   My only complaint about the Brymen meter is that it does not store all the engine parameters on power down.  So for me, I have to change the setup every time I use the meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 10, 2018, 12:06:04 am
Quote
Now I had two dead meters. Two dead meters that cost me about $1000.

Article on the Fluke 189 & 187.
https://www.edn.com/electronics-blogs/powersource/4458696/Dead-meters-expose-battery-terminal-design-issues (https://www.edn.com/electronics-blogs/powersource/4458696/Dead-meters-expose-battery-terminal-design-issues)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on September 10, 2018, 02:53:01 am
Really interesting article; it exposes how many design choices can be seen differently by each person. The amusing rambling about opening the battery compartment certainly gave me a chuckle.

A few other things stroke me as quite strange; the dissatisfaction with the corrosion on the terminals, despite there were actual battery leakages; the claims the Klein meter does not measure the 1M\$\Omega\$ resistor, despite the specs mention up to 40M\$\Omega\$...
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on September 10, 2018, 04:10:41 am
Clearly we need to see a meter hooked up to the ~10 kV circuit on the high side of a mains distribution transformer. Though it would have to be a disposable meter as I think it would be completely vaporized in a fireball of epic proportions...

What is the point here, of course the meter burns up and so does the person near it.
People have been killed connecting a Fluke 87 to 2.3kV MCC. Look at the Eddie Adams' Arc Flash Fatality Video.

If there is a point, it would be education. Many novices may get the impression that if you generate 30 kV from some kind of ignition transformer you get sparks across a spark gap. This may lead to the (wrong) deduction that a few tens of kilovolts produces sparks. Therefore if you hold something close to a transmission line carrying 10 kV or so then a few sparks will jump across the gap when you get close enough. I don't think I've seen a video that shows what actually happens in this case, when the source of high voltage has no current limit and near zero source impedance.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 10, 2018, 11:47:58 am
Clearly we need to see a meter hooked up to the ~10 kV circuit on the high side of a mains distribution transformer. Though it would have to be a disposable meter as I think it would be completely vaporized in a fireball of epic proportions...

What is the point here, of course the meter burns up and so does the person near it.
People have been killed connecting a Fluke 87 to 2.3kV MCC. Look at the Eddie Adams' Arc Flash Fatality Video.

If there is a point, it would be education. Many novices may get the impression that if you generate 30 kV from some kind of ignition transformer you get sparks across a spark gap. This may lead to the (wrong) deduction that a few tens of kilovolts produces sparks. Therefore if you hold something close to a transmission line carrying 10 kV or so then a few sparks will jump across the gap when you get close enough. I don't think I've seen a video that shows what actually happens in this case, when the source of high voltage has no current limit and near zero source impedance.
You couldn't get your fill on YT?  There are so many videos of humans, monkeys, birds, snow ... getting across high voltage lines.  There were some pretty good educational videos put out by on of the power companies.  They had a portable transmission line that they would use for demonstrations.   

For my own personal use, I'm never near any source like this.  If I were, a handheld meter is not something I would have with me.   :-DD   In this thread I am really only interested in a meter's ability to survive low energy transients.  It has morphed into drop, chemical resistance, life cycling and a few experiments with DC voltages.  I doubt I will ever show any testing using an actual AC main for a source.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 10, 2018, 09:35:07 pm
You can get sparks easly on static discharges on you're car, on a shopping cart or even with two tiny 3,45VA back to back transformers that can be found on older cordless phones or cell phones ( e.g. nokia 5110 chargers) and i found that 6VA can do a good job in taking out a triac silently by the worst way  without tripping the multimeter and this is low power 230V isolated, so imagine novices using HV power sources and their meters ...


About the meters the Brymen, Fluke , Amprobe for example they make for electricians , so they have the experience and hard time on how to build a multimeter. Try the 121GW and the Brymen BM235 EEVdition :P

 
 One thing it would be good is to show some transients that can appear on the 230Vac line to demonstrate what multimeters are dealing in the field .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2018, 05:38:17 am
You can get sparks easly on static discharges on you're car, on a shopping cart or even with two tiny 3,45VA back to back transformers that can be found on older cordless phones or cell phones ( e.g. nokia 5110 chargers) and i found that 6VA can do a good job in taking out a triac silently by the worst way  without tripping the multimeter and this is low power 230V isolated, so imagine novices using HV power sources and their meters ...


About the meters the Brymen, Fluke , Amprobe for example they make for electricians , so they have the experience and hard time on how to build a multimeter. Try the 121GW and the Brymen BM235 EEVdition :P
 
 One thing it would be good is to show some transients that can appear on the 230Vac line to demonstrate what multimeters are dealing in the field .
Imagine having a document of how every novice has damaged a meter.   :-DD  I will be the first to admit, I damaged my poor analog Radio Shack meter several times doing all sorts of stupid things to it.   :-DD 

At some point, I do plan to run a mature version of the 121GW.   I doubt that is going to happen this year like I had hoped.  Based on my initial tests on the prototype, I am not holding out much hope but then again, Dave mentioned they are making a change to the one clamp which I know is a weak section of the meter. 

I've seen pretty good results with Brymen, Fluke, HIOKI and the Gossen from a robustness stand point.  The AMPROBE AM530 did not do very well and the AM510 I consider the minimum.  I think both are UNI-T products.   I wonder about the AMPROBE pocket meter that True mentions having four dead ones.  Again, we have no way of knowing how their meters were treated but I am curious how it holds up compared the others I've looked at. 

Again, I doubt I will ever show actual AC line tests.  There is the cost to set up to run a test like this.  The generator, filters, blast shield...   If you go that far, you may as well have it all certified.  I suspect it would be more cost effective to rent a lab for a few days and just run several.   Cheapest and safest thing is just read about it and watch some videos.   Maybe you would want to take this on? 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 11, 2018, 10:59:25 am
Hi

Forgot the Hioki really nice meter and Gossen it a shame for the sensitivity on EMC and the relay, because it would give a fine meter. The Amprobe's i'm talking about are 510 and 550 ( check this specs : http://www.amprobe.com/amprobe/usen/digital-multimeters/am-500-digital-multimeter-series/amp-am-550.htm?pid=74037 (http://www.amprobe.com/amprobe/usen/digital-multimeters/am-500-digital-multimeter-series/amp-am-550.htm?pid=74037)).

Noted about the 230V, also read some stuff. I've notice a spike  of almost 1Kv on a 230V outlet years ago on first DMM scope.  (edit )I imagine exemplifying a very small isolation, with the triac to lower the energy and measure the voltage of the AC with a spark gap between two series terminals that would connect to a load , e.g. bulb but that's not a safe example
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2018, 04:55:35 pm
This guy also experiments with various power line equipment.  Here he shows a cheap meter connected to one. 

https://www.youtube.com/watch?v=8nCjvNBs150 (https://www.youtube.com/watch?v=8nCjvNBs150)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 11, 2018, 05:05:29 pm
Looks like Voltlog put together a good overall review of the Brymen BM27s (AMPROBE PB55A) that True was posting about.  Looks like it's better than the pocketmeters I have looked at.  Lot's of slits in the board.  May be interesting to see how well it would hold up.
 
https://www.youtube.com/watch?v=H_enb3bN7c4 (https://www.youtube.com/watch?v=H_enb3bN7c4)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 11, 2018, 08:49:22 pm
This guy also experiments with various power line equipment.  Here he shows a cheap meter connected to one. 

https://www.youtube.com/watch?v=8nCjvNBs150 (https://www.youtube.com/watch?v=8nCjvNBs150)


This is good as my old rebranded mastech that blowed in my hand while reading the mains in AC voltage...

https://www.eevblog.com/forum/testgear/new-aneng-q1-9999-counts/?action=dlattach;attach=458422 (https://www.eevblog.com/forum/testgear/new-aneng-q1-9999-counts/?action=dlattach;attach=458422)

https://www.eevblog.com/forum/testgear/new-aneng-q1-9999-counts/?action=dlattach;attach=458389 (https://www.eevblog.com/forum/testgear/new-aneng-q1-9999-counts/?action=dlattach;attach=458389)

https://www.eevblog.com/forum/testgear/new-aneng-q1-9999-counts/?action=dlattach;attach=458395 (https://www.eevblog.com/forum/testgear/new-aneng-q1-9999-counts/?action=dlattach;attach=458395)

I have two pocket meters, being the protek A800 (1994 i believe ) the first multimeter and working and the last one an offered uni-t ut120c, which is quite handy to measure low energy stuff.

https://www.eevblog.com/forum/chat/show-your-multimeter (https://www.eevblog.com/forum/chat/show-your-multimeter)!/?action=dlattach;attach=485816

Maybe a new batch of new pocket meters should meet the joeqsmith test JIG :P including the new ANENG 302 :P
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on September 11, 2018, 11:29:20 pm
Aneng 302??
never heard of it, that company is bringing out meters faster than i can keep up!!
i like the pen-style one btw.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 11, 2018, 11:35:19 pm
Here is the anouncement by Voltlog :

https://www.eevblog.com/forum/testgear/aneng-302-pocket-meter-by-voltlog/msg1732637/#msg1732637 (https://www.eevblog.com/forum/testgear/aneng-302-pocket-meter-by-voltlog/msg1732637/#msg1732637)

It's been a while :P And it will do a good light show :P CATIII 300V.... yeah...

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 12, 2018, 12:02:00 am
This is good as my old rebranded mastech that blowed in my hand while reading the mains in AC voltage...

Hey, you have a way to test these meters.  Now we need to get you to start reviewing them without loosing a hand in the process.   :-DD

I've been watching some of the videos of the guy with the pole pig.  He talks about getting across one of the large caps.   :palm:  Beyond making large arcs, I have not seen him doing anything with them.   

Personally, I liked some of PhotonicInduction's videos. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 12, 2018, 12:45:17 am
They just don't like much the mains voltage :P Well my memory that i had was the voltage 1536 on the display, a bang / flash. I think it will be simple by just leaving plugged into a mains socket inside a hollow explosion / fire container and let the camera take the shot., Maybe some wires to monitor the voltage. but definitly far away of  sight

Speaking of pole pigs :P .:

https://www.youtube.com/watch?v=hzAB8fgFmHo (https://www.youtube.com/watch?v=hzAB8fgFmHo)

This is too dangerous ... ( edit) as well PhotonicInduction . put some DMM's extra and they will vaporize.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 14, 2018, 01:13:03 am
A few questions and comments.

https://www.youtube.com/watch?v=bgz-pqg0rKo (https://www.youtube.com/watch?v=bgz-pqg0rKo)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 16, 2018, 02:52:46 pm
Brand new Brymen / AMPROBE arrived. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 16, 2018, 04:07:26 pm
Chances are that it will survives 4kv that pocket brymen/Amprobe,
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on September 16, 2018, 04:11:39 pm
Brand new Brymen / AMPROBE arrived.

This is the one that is reported to fail without apparent cause after a certain amount of time?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 16, 2018, 04:39:58 pm
Brand new Brymen / AMPROBE arrived.

This is the one that is reported to fail without apparent cause after a certain amount of time?

True reported four of them failed the same which makes me wonder.   Maybe they will chime in with some additional information.
Title: Re: Handheld meter electrical robustness testing.
Post by: 001 on September 16, 2018, 06:21:32 pm
Hi!
IMHO it is a sort of populism or show

No reason to destroy gear  :palm:

See hysteric tread here https://www.eevblog.com/forum/testgear/dangerous-multimeter-mastech-m890g-m890g2-(aka-dc-electronics-dc03)/ (https://www.eevblog.com/forum/testgear/dangerous-multimeter-mastech-m890g-m890g2-(aka-dc-electronics-dc03)/)

NO PROBLEM with meter but topicstarter is angry!!!  :-DD

I also use some DMM for about 18 years. Yes, it is not masterpiece - you got what you pay for. But it WORKS anyway.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on September 16, 2018, 06:47:17 pm
Yeah that's the kind of the multimeters that are very disposable :P You pay what you get. Sometimes you get good stuff or not :P

Some pocket meters actually have more protection input than the one on the link .

https://www.eevblog.com/forum/blog/eevblog-1083-pocket-mutimeter-shootout/?action=dlattach;attach=451189 (https://www.eevblog.com/forum/blog/eevblog-1083-pocket-mutimeter-shootout/?action=dlattach;attach=451189)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on September 16, 2018, 07:37:05 pm
Hi!
IMHO it is a sort of populism or show

Hello.  All of the testing has created a small channel.  I wouldn't say it was popular. If you are suggesting that the tests are somehow skewed based on popularity of a product, I am interested in understand why you would feel this way.  They basically all see the same transients.

No reason to destroy gear  :palm:
I have talked about the reasons why I run these tests.  It does not mean that you personally will find any value in the data.  That's not one of my goals. 

See hysteric tread here https://www.eevblog.com/forum/testgear/dangerous-multimeter-mastech-m890g-m890g2-(aka-dc-electronics-dc03)/ (https://www.eevblog.com/forum/testgear/dangerous-multimeter-mastech-m890g-m890g2-(aka-dc-electronics-dc03)/)

NO PROBLEM with meter but topicstarter is angry!!!  :-DD

I also use some DMM for about 18 years. Yes, it is not masterpiece - you got what you pay for. But it WORKS anyway.
I have not had a low end meter survive nearly this long.   I have a Mastech that has various problems.  I'm on my third one now in the last 10 years or so.

They seem upset about the rating on the meter.  I personally am not too concerned about the safety ratings. I seldom work do anything that would require it.  At home for my hobby, I dare say it's never.   Which again is why you see me testing at such low energy levels.  I am more interested in a meter's ability to survive some basic low energy transients that how safe it would be with an arc flash for example.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 14, 2018, 11:20:28 pm
Looks like True stopped posting.   I started to look at the Amprobe meter today and would have liked to have had them check a few things.  I hope to run it this week some time.  If anyone has any special tests they would like to have ran, let me know in the next day or so and I will see if I can include it. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 15, 2018, 09:45:51 pm
Humm interesting pocket meter, EMC Meets EN61326 , Hit with the ESD gun :P

Test if it is susceptible to RF ... and also check size comparisson with previous pocket meters,
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 16, 2018, 09:49:30 am
I believe that in that videos where Dave selected the best pocket meter of price range didn't include the amprobe pm55 and voltlog it had an aneng, mastech and the uni-t 120c. In that case can you put the aneng like meter or fluke 101 ?

 Sorry to be persistent but it looks to me a little bigger in height than the ones that have being tested.


Well i have my offered pocket meter ut-120c and it's has less usability than i expected :( The probes don't stick inside wago's connectors so no 230V experiences :P Yes they can be placed on the test pins but metal gets exposed..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 16, 2018, 10:52:48 am
I believe that in that videos where Dave selected the best pocket meter of price range didn't include the amprobe pm55 and voltlog it had an aneng, mastech and the uni-t 120c. In that case can you put the aneng like meter or fluke 101 ? 

Sorry to be persistent but it looks to me a little bigger in height than the ones that have being tested.

I am not sure what you are asking.  Are you wanting to know if the Fluke 101 will fit inside the case that was supplied with the PM55A? 

The dimensions are normally in the manuals which are on-line.  The PM55A is 113 x 53 x 10.2 mm.   The Fluke 101 is 130 mm x 65 mm x 27mm.   The internet is powerful.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 16, 2018, 03:54:47 pm
Yes there are manuals and specs but for example if you look at the manual of the unit 204a the picture of the meter does appear like the 203 more because of the curved lcd.

A visual comparisson always helps more. I was suggesting putting side by side the amprobe and fluke 101. 

My print is out of inks to do a real size comparrison  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 16, 2018, 04:13:55 pm
Looks like True stopped posting.
001 as well.  ;D

Joe, one interesting meter that you may consider testing in the future is the nice PM300 from Sanwa (https://www.eevblog.com/product/pm300/); it is rated for CATIV 300V / CAT III 600V and is quite well built. It is protected by a GDT and a Varistor on a string of resistors.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=549116)
(shameless plug)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 16, 2018, 05:10:16 pm
A visual comparisson always helps more. I was suggesting putting side by side the amprobe and fluke 101. 

No problem.  I will show it next to the 101 and a few others.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 16, 2018, 05:13:19 pm
Looks like True stopped posting.
001 as well.  ;D

Joe, one interesting meter that you may consider testing in the future is the nice PM300 from Sanwa (https://www.eevblog.com/product/pm300/); it is rated for CATIV 300V / CAT III 600V and is quite well built. It is protected by a GDT and a Varistor on a string of resistors.


Think the SANWA would survive to higher levels than this little Brymen?  Did Dave do anything to it electrically in his reviews?   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 16, 2018, 07:15:25 pm
Looks like True stopped posting.
001 as well.  ;D

Joe, one interesting meter that you may consider testing in the future is the nice PM300 from Sanwa (https://www.eevblog.com/product/pm300/); it is rated for CATIV 300V / CAT III 600V and is quite well built. It is protected by a GDT and a Varistor on a string of resistors.


Think the SANWA would survive to higher levels than this little Brymen?  Did Dave do anything to it electrically in his reviews?   
Just a hunch but I suspect so, given that Sanwa is a very reputable japanese brand that would not lie about CAT ratings.

Dave did not put it through its paces, though.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 16, 2018, 09:05:33 pm
And if you think the harbor freight meter is bad , then check this:

https://youtu.be/R693vS09hoo

Lucky one on the mains :P
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 16, 2018, 10:35:34 pm
This is the same model that Harbor Freight sells. They and many other no-name brands around the globe.

I did a comparison with a few models manufactured over the years (in portuguese) - you can tell the similarities.

https://youtu.be/eskV_OJtH48

(Joe, sorry for the plugs, but it is quite rare that I can link a video to someone that understands what I am actually talking on my videos :D )
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 16, 2018, 11:41:17 pm
Thanks for sharing the video. At 12:32 the rotary switch was a bit loose :P

jesus mine that blow on the mains was from mastech, in 2000 .  input voltage was blown away.. PTC, traces :P



And they tend to be minimal has years go... The other 3 dollar meter didn't have a fuse :P and had some resistors that may no be good to handle the input voltage.

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on October 17, 2018, 12:06:12 am
Yep, they get more and more simplified with each revision. It's the art of cost shaving.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 17, 2018, 02:06:01 am
Looks like True stopped posting.
001 as well.  ;D

Joe, one interesting meter that you may consider testing in the future is the nice PM300 from Sanwa (https://www.eevblog.com/product/pm300/); it is rated for CATIV 300V / CAT III 600V and is quite well built. It is protected by a GDT and a Varistor on a string of resistors.


Think the SANWA would survive to higher levels than this little Brymen?  Did Dave do anything to it electrically in his reviews?   
Just a hunch but I suspect so, given that Sanwa is a very reputable japanese brand that would not lie about CAT ratings.

Dave did not put it through its paces, though.

I've had meters that were certified to the safety standards do very poorly in my tests.  I've never looked at any Sanwa products but this is going to be the 6th Brymen I've looked at.   We have yet to see one fail on the new generator.   Now what's going on with all these meter's True has seen get damaged, hard to say.   Maybe they live in a very humid environment.  Maybe next to a large body of salt water.   Perhaps they are a Fluke fanboy and just don't like seeing these Brymen's hold up so well.  Hard to say.

The PM300 does not appear to be available off Amazon. Maybe it's not popular.  Dave does seem to stock them but doesn't seem to offer them on Amazon.   Maybe once the 121GW is stable  I will add one to the order. 
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on October 17, 2018, 06:25:24 pm
I found no evidence the Sanwa PM300 has 61010 certification. I thought the manual says "designed to" or some other ballyhoo.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 17, 2018, 06:34:15 pm
I found no evidence the Sanwa PM300 has 61010 certification. I thought the manual says "designed to" or some other ballyhoo.
https://overseas.sanwa-meter.co.jp/items/detail.php?id=405# (https://overseas.sanwa-meter.co.jp/items/detail.php?id=405#)
https://www.sanwa-meter.co.jp/prg_data/goods/img/PH61491811587.pdf (https://www.sanwa-meter.co.jp/prg_data/goods/img/PH61491811587.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on October 17, 2018, 06:59:09 pm
Yup, you're getting fooled. You have to be hard-ass with manufacturers and safety claims.
"This instrument is a pocket-type digital multimeter with rms value response, designed for measurements within the range specifed as CAT.IV 300 V / CAT.III 600 V in IEC61010."
No file or certificate number, no agency approval logo. The approvals report Dave has is only for 61000 EMC. So I believe the muiltimeter is not certified.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 17, 2018, 07:24:26 pm
Near the bottom of the PDF datasheet it says EC61010-1, IEC61010-2-030, IEC61010-2-33, IEC61010-31

There is no certification approval from any agency if the meter is self certified by the manufacturer. IME Japanese manufacturers seem to refrain from using third parties for that. Joe's Hioki, for example, only has a self-produced DoC that does not guarantee any third party certification. It does not mean it was not tested and certified, but you need to trust if the manufacturer has done it properly.

Thus the only claim that can be done is the manufacturer did not perform third party certification.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on October 17, 2018, 08:09:57 pm
Only a government-accredited agency can evaluate and certify ("approve") to those safety standards, at least in North America.
No self-declaration is permitted there.

It's a long snakey path to follow safety legislation in any country, who is the "authority having jurisdiction", who makes it law that products have approvals. Once I had to convince an asshole CEO that safety approvals were required for some equipment and it was brutal in the USA. Several states do not have the National Electrical Code in effect (https://www.nfpa.org/NEC/NEC-adoption-and-use/NEC-adoption-maps) so asshole CEO said you can sell anything (electrical) there and no need for engineering to worry  :palm: I almost lost my job refusing to sign/stamp that shit.

For multimeters it's certainly OSHA (at work) or corporate policy they have credible safety certifications.

The liability for a product failing a safety claim is what keeps most companies from selling gear with fake approvals. I see a few Japanese companies with no formal safety approvals, only claims to meet x standard.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 17, 2018, 09:43:17 pm
So that claims about safety standards are done internally by the company?

Well what about the reviewed on the pocket shootout by Dave , the Sanwa PM-3?

https://www.sanwa-meter.co.jp/prg_data/goods/img/PH61496794132.pdf (https://www.sanwa-meter.co.jp/prg_data/goods/img/PH61496794132.pdf)

It has one safety standard ... but in the manual...

Code: [Select]
Safety: IEC 1010-1(EN61010-1)
≦DC・AC 500V: Designed to protection ClassII
requirement of IEC 1010-1, Pollution degree II.
EMC: EN50081-1 (EN55022), EN50082-1 (EN61000-4-2)
EN50082-1 (EN61000-4-3), EN50082-1 (ENV50204)

A ton of it ... source : http://www.mantech.co.za/datasheets/products/pm3_sanwa.pdf (http://www.mantech.co.za/datasheets/products/pm3_sanwa.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 01:48:47 am
Only a government-accredited agency can evaluate and certify ("approve") to those safety standards, at least in North America.
No self-declaration is permitted there.
I am not sure if that changed, but my memory may be failing. A NRTL was usually required for UL or CSA 61010 approvals (other standards may be similar). Regardless, not everyone that sells these products is required to have an agency certification mark - only third party certification testing is necessary and a proper documentation must be available to the regulatory agencies.

It's a long snakey path to follow safety legislation in any country, who is the "authority having jurisdiction", who makes it law that products have approvals.
Precisely. It is quite hard to follow every single country out there. That is why companies tend to defer to third parties with Notified Bodies and certain places allow Harmonized standards. It tends to ease things across borders.

The liability for a product failing a safety claim is what keeps most companies from selling gear with fake approvals. I see a few Japanese companies with no formal safety approvals, only claims to meet x standard.
Yes, but it is all a CYA operation. If the company stands behind its own certification procedure, documentation and manufacturing control, the liability is entirely owned by them - otherwise, pass the baton to the third party. :)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 01:51:01 am
Joe, there are some interesting tests and information on the document below from National Instruments. A little outdated, but perhaps it gives you some idea for testing.

ftp://ftp.ni.com/pub/devzone/Safety.pdf
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on October 18, 2018, 03:06:18 am
The proof is the product having a Certification Agency's sticker with logo and file number, or that in the owner's manual.
UL Certifications Directory (http://database.ul.com/cgi-bin/XYV/cgifind/LISEXT/1FRAME/srchres.html)
Intertek Product Directories (http://www.intertek.com/directories/)

These directories list Brymen, Uni-Trend, Fluke, Mastech, Flir, Keithley, Klein, Keysight etc. multimeter safety certifications giving proof the product was tested and passed.

No sign of any listings for Sanwa Electric Instrument Co. Ltd.

If you want to fake safety approvals for your product, there are many strategies:

1. Use the term "designed to" in all documentation
Meaning the engineers had good intentions but did not test the result to any standard. The expression is a red flag for claims about safety because a design is not a test and you're in a conflict of interest anyhow, this is why third-parties are used.

2. Use old standards
Old, deprecated safety standards are simpler and much easier to meet.
IEC 1010 was from about 1988-1993, when 61010 superceded it.

3. "We have thousands in use and never had a problem"
The number of units sold and hours without incident mean the product is safe. What more proof do you want?

4. Get approvals from a small, unheard of, or inept certification agency
They are happy to take your money and fudge the results, after all they are not liable for testing only as they were instructed to.

As an engineer I have been through the wringer with corrupt CEO's and engineering/product managers, but also a certification agency happy to do the work but not actually qualified for the standard they claimed and pumped out stickers for. We could talk more about NRTL but there are always loopholes people exploit.

My position is the Sanwa multimeters are high quality builds but unknown as far as safety, misleading in their 61010 claims. I'd want to know there are no blatent design/assembly blunders making a clearance violation allowing unexpected arcing, for example.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 18, 2018, 03:15:29 am
Wow, someone still has an FTP site.   :-DD   Sorry but I can't get to it.  It won't answer a ping and FTP will timeout.   If you downloaded it and feel it could be of interest, just upload it on this site or put it on Googledocs.   You could also just describe the test/s you would like to see ran. 


Google shows the title as:
"PRODUCT SAFETY: Expanding Markets Mean ... - National Instruments"
North America. – National standards and laws (OSHA). – NRTL certifications, descriptive reports and N.A. Marks (UL/CSA). – UL/CSA standards similar to IEC
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 18, 2018, 03:27:32 am
Watched Dave's trash dive last night and saw a couple of small Schaffners.   Well he did come up with the toggle bot.  Maybe we will see some form of transient testing in the future.   

https://youtu.be/YX0MJjq9MuU?t=439

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 11:19:42 am
Wow, someone still has an FTP site.   :-DD   Sorry but I can't get to it.  It won't answer a ping and FTP will timeout.   If you downloaded it and feel it could be of interest, just upload it on this site or put it on Googledocs.   You could also just describe the test/s you would like to see ran. 


Google shows the title as:
"PRODUCT SAFETY: Expanding Markets Mean ... - National Instruments"
North America. – National standards and laws (OSHA). – NRTL certifications, descriptive reports and N.A. Marks (UL/CSA). – UL/CSA standards similar to IEC
I put the link directly, as the forum software was inserting bogus http:// stuff at the beginning of the link (it was also surprised about the fact a FTP site existed :D )
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 11:33:02 am
The proof is the product having a Certification Agency's sticker with logo and file number, or that in the owner's manual.
UL Certifications Directory (http://database.ul.com/cgi-bin/XYV/cgifind/LISEXT/1FRAME/srchres.html)
Intertek Product Directories (http://www.intertek.com/directories/)

These directories list Brymen, Uni-Trend, Fluke, Mastech, Flir, Keithley, Klein, Keysight etc. multimeter safety certifications giving proof the product was tested and passed.
That is where you are getting confused: the proof is not having a listing on a site but instead a statement or a test report that says so. You could potentially consult with them and obtain the latest test reports or statements of compliance (these do not need to be readily downloadable). The listing and agency mark is a product from one of these cert agencies and not a requirement enforced by regulatory agencies to have your product available for sale. Sure, you can make the case that having your product listed will help boost sales, especially in this market, but a company or a product that is not listed is not necessarily untested and does not necessarily fail to meet the regulation (UL/EN/CSA 61010 in this case).

My position is the Sanwa multimeters are high quality builds but unknown as far as safety, misleading in their 61010 claims. I'd want to know there are no blatent design/assembly blunders making a clearance violation allowing unexpected arcing, for example.
That is a fair assessment. Until you see the test document or declaration in front of you, you can't be sure.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 18, 2018, 11:54:06 am
And if you think the harbor freight meter is bad , then check this:

https://youtu.be/R693vS09hoo

Lucky one on the mains :P

that's the one i posted some pictures of a week or 3 back while making comments about the 1mm clearance.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 05:52:33 pm
Slide 18 for the suggestion of a test...  :-DD

Slides 21 ~ 23 as good references when you are analyzing or making modifications on a DMM.

Anyhow, I just thought it was nice how they presented the information. Quite clear in my opinion.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on October 18, 2018, 08:55:43 pm
I'm trying to keep it simple for owners and youtube reviewers of multimeters to check if the product is truly compliant, avoiding regulatory politics.

The certification directories and product labelling are reasonable proof of compliance. Although not completely, as ANENG only went for 3V in their 61010 assessment - true for the ohms and diode-test functions lol.

I've had customers such as refineries demand safety certifications for the electrical products I'm designing/selling. They would not purchase anything less, obviously due to the risk.

"... a company or a product that is not listed is not necessarily untested and does not necessarily fail to meet the regulation (UL/EN/CSA 61010 in this case).

Unless I'm misunderstanding you, I don't agree - ma and pa can't test compliance to a safety standard in their garage, write up a report and say it's all good. Too much chance of corruption and mistakes.

OSHA list of NRTL's: (https://www.osha.gov/dts/otpca/nrtl/nrtllist.html)
"A Nationally Recognized Testing Laboratory (NRTL) is a private-sector organization that OSHA has recognized as meeting the legal requirements in 29 CFR 1910.7 to perform testing and certification of products using consensus based test standards. These requirements are:

    -The capability to test and evaluate equipment for conformance with appropriate test standards;
    -Adequate controls for the identification of certified products, conducting follow-up inspections of actual production;
    -Complete independence from users (i.e., employers subject to the tested equipment requirements) and from any manufacturers or vendors of the certified products; and
    -Effective procedures for producing its findings and for handling complaints and disputes.

An organization must have the necessary capability both as a product safety testing laboratory and as a product certification body to receive OSHA recognition as an NRTL."

I think the safety assessments done professionally end up listed and labelled.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 18, 2018, 09:37:03 pm
I have a question about a clamp meter Unit 204A that has intertek / ETL logo and a S.N. Number :P

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=503906 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=503906)

From here it looks good but check this on the manual (see attachment) On the temperature sensor 1K resistor in series. You plug the meter into 230V in this mode and its bye bye...

So they may ommit some functions during the certification?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 09:44:14 pm
"... a company or a product that is not listed is not necessarily untested and does not necessarily fail to meet the regulation (UL/EN/CSA 61010 in this case).

Unless I'm misunderstanding you, I don't agree - ma and pa can't test compliance to a safety standard in their garage, write up a report and say it's all good. Too much chance of corruption and mistakes.
That is fine. It is your opinion. It doesn't mean it is enforceable/applicable/true for all scenarios/countries/etc.

OSHA list of NRTL's: (https://www.osha.gov/dts/otpca/nrtl/nrtllist.html) (...)
Yes, that is correct. We have established that US/Can is different than worldwide. What OSHA says is restricted to US.

Look, I have no horse in this race. I don't really care if Sanwa or Hioki or Uni-T or Aneng have tested their stuff or not - I am an enthusiast that happens to be involved professionally with this whole compliance deal (not test equipment). My attempt with this discussion is to clarify that the marketing product offered by certification agencies to promote compliance ("UL listed", "ETL", "TÜV Rheinland" markings) is not the only way to demonstrate a product's compliance and should not be a pre condition to dismiss a product in this area.

I think we sprinkled this thread with enough boring compliance stuff. I will refrain from replying on this subject. Peace.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 18, 2018, 09:47:25 pm
Slide 18 for the suggestion of a test...  :-DD

Slides 21 ~ 23 as good references when you are analyzing or making modifications on a DMM.

Anyhow, I just thought it was nice how they presented the information. Quite clear in my opinion.

It looks like this person updated their presentation in 2010.  Do a search for their name or that UL flame test.   They added a few pages.

I think I have melted a meter with a soldering iron before but I've never torched one.  I keep the Halon handy if that time ever presents itself.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 18, 2018, 09:48:15 pm
I have a question about a clamp meter Unit 204A that has intertek / ETL logo and a S.N. Number :P

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=503906 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=503906)

From here it looks good but check this on the manual (see attachment) On the temperature sensor 1K resistor in series. You plug the meter into 230V in this mode and its bye bye...

So they may ommit some functions during the certification?

I wish I had access to a recent copy of the standard. That would better clarify this scenario.

AFAIK the CAT testing does not guarantee the survivability of the meter - only the survivability of the operator.

That is the sole reason why Joe's tests are so interesting - they give an idea of robustness but are too weak to test survivability (maximum he can get is a *poof* and not a *BOOOOOM*) :)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 18, 2018, 10:14:51 pm
If I were experimenting at home with levels that could make a BOOOOM,  I may actually have some interest in safety.  Then again, my lab and power distribution would be much more interesting than it is!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 18, 2018, 10:19:48 pm
Looks like True stopped posting.
001 as well.  ;D

Joe, one interesting meter that you may consider testing in the future is the nice PM300 from Sanwa (https://www.eevblog.com/product/pm300/); it is rated for CATIV 300V / CAT III 600V and is quite well built. It is protected by a GDT and a Varistor on a string of resistors.


Think the SANWA would survive to higher levels than this little Brymen?  Did Dave do anything to it electrically in his reviews?   
Just a hunch but I suspect so, given that Sanwa is a very reputable japanese brand that would not lie about CAT ratings.

Dave did not put it through its paces, though.

Take your best guess where you feel the Brymen will fail.   I will consider a breakdown in an unintended area a failure.  It fits in a shirt pocket so things are pretty tight in there.   2KV?    What about the SANWA you mention?   Think it's double?  4KV? 

Based on what True posted, it may not even make it that far in the testing!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 18, 2018, 11:37:57 pm
Working with 230V isolated from mains, 6VA currently and it can put in a lot of trouble if safety is discarted. At least is documented on the meter's manual.


Guess for Brymen... pocket meters... disposable ... personal ut120c freezed when battery got low....  maybe with issue ESD wil take it out .

 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 12:00:25 am
1 vote for ESD
1 vote for > 6KV
   

This will be the sixth Brymen I have looked at in detail.  I've been very impressed with how well they have done.   I'm going to guess that it can survive at least to the levels my low voltage generator can put out.  So more than 6KV. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 19, 2018, 10:10:39 am
Wow there is a discrepancy between odds. It may be the version for the bad or good unit. If it survives 6kv then its a Brymen pocket meter well done. Maybe sanwa has some touch to it...

The setup of isolated 230v does not make boom but it can buzz the transformers or bad connections, eg v shape banana plugs.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 11:18:08 am
I purchased a new unit after my PM55A had failed, only to find a PM55 I gave to a friend also failed. I tested a PM55 I had and it too had failed. The replacement? Well, it tested good (testing 5V in auto mode, and shorting probes, that's it...); after a month when I went to use it to test a low voltage DC circuit again, it showed low battery ... and sure enough it failed too.

If True were still around, they may vote that it won't survive a basic functional test.   :-DD 

I've been running some low voltage, non-destructive tests, looking for some test case that would go along with what True posted.  At least four meters with the same failure mode, I should be able to replicate it.   Then again, maybe True was Trolling and there's no Truth in what was posted?   Hard to say but you can be assured that I will do my best to send this meter to the recycle bin.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 19, 2018, 12:11:29 pm
With that test we can see the meter in action. Trash bin? Pocket meters really after seeing my ut120c hang the lcd on low bat i believe that can happen if similar chipsets are being used.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 19, 2018, 03:30:24 pm
I re-watched Dave's shootout and saw how electrically well built the Brymen was - although mechanically flawed. The Amprobes also took a beating, therefore my guess is that the little PM55A will fail at a higher level than the ESD gun. I would guess ≥6kV.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 06:55:32 pm
So that's 

1 vote for won't make it past the functional test  :-DD taking liberty with True's posts until they return.   :-DD
1 vote for ESD
2 vote for > 6KV

If you feel the SANWA can survive to even higher levels than the Brymen, are you thinking it's in Fluke 101/107 territory? 

What do you feel is a mechanical flaw with the Brymen?   There is something I really don't like about the mechanics but I doubt it's the same problem.   Because often I run these meters to failure and I try to analyze why they fail, I want to be able to run the PCB open case.  The way the LCD, switch and battery are mounted to the case, it would make it difficult to work on.   I'm sure we will find out just how difficult. 
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on October 19, 2018, 06:57:08 pm
Joe, something you might want to look into with the bigger Brymens and maybe other meters too:


Also found another issue with the BM867s. If it’s sitting in series with the PA monitoring current it goes bloody mental when you key down. Fluke, fine. Keysight, fine. Hmm. This is why I haven’t dropped my review yet. I still like it but not for that.

Not sure what you've got to replicate RF keying or if you even want to give yourself a slight RF fry up.  :-\
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 07:52:01 pm
Joe, something you might want to look into with the bigger Brymens and maybe other meters too:


Also found another issue with the BM867s. If it’s sitting in series with the PA monitoring current it goes bloody mental when you key down. Fluke, fine. Keysight, fine. Hmm. This is why I haven’t dropped my review yet. I still like it but not for that.

Not sure what you've got to replicate RF keying or if you even want to give yourself a slight RF fry up.  :-\

What's this about?   I do normally sweep them to see if there are areas they are sensitive at.  Post a link or details about exactly what they are doing, their test setup, modulation....

I played around with a few of my meters once I picked up that Gossen at 10V/m, swept to a GHz. 
https://youtu.be/wYuzFtoHMqg?list=PLZSS2ajxhiQBTCU8Mq_i9jidT024A0dV6&t=840

I still have my old Vibroplex
https://youtu.be/QBho9XD7VPQ?t=79
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on October 19, 2018, 07:58:53 pm
Joe, something you might want to look into with the bigger Brymens and maybe other meters too:


Also found another issue with the BM867s. If it’s sitting in series with the PA monitoring current it goes bloody mental when you key down. Fluke, fine. Keysight, fine. Hmm. This is why I haven’t dropped my review yet. I still like it but not for that.

Not sure what you've got to replicate RF keying or if you even want to give yourself a slight RF fry up.  :-\

What's this about?   I do normally sweep them to see if there are areas they are sensitive at.  Post a link or details about exactly what they are doing, their test setup, modulation....

I played around with a few of my meters once I picked up that Gossen at 10V/m, swept to a GHz. 
https://youtu.be/wYuzFtoHMqg?list=PLZSS2ajxhiQBTCU8Mq_i9jidT024A0dV6&t=840 (https://youtu.be/wYuzFtoHMqg?list=PLZSS2ajxhiQBTCU8Mq_i9jidT024A0dV6&t=840)
I know and watched all you did with the Gossen to get it immune to the near field and magnetiser sensitivity.
You can glean a little more about the circumstances here:
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1898834/#msg1898834 (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1898834/#msg1898834)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 08:15:17 pm
Hummm.  I have no idea what they are doing.  You don't think they stuck the meter between the output and the load at 7MHz do you?   :-DD  I am guessing they are looking at the DC supply side but I can't find where they show a lot of details.  Maybe they will write something up and post some pictures. 

I'm sure I could come up with 7MHz at 25W. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 19, 2018, 08:26:19 pm
If you feel the SANWA can survive to even higher levels than the Brymen, are you thinking it's in Fluke 101/107 territory? 
I really don't know. I suspect both would be equivalent (I hope I don't eat my hat if you happen to test the PM300 in the future).

What do you feel is a mechanical flaw with the Brymen?   There is something I really don't like about the mechanics but I doubt it's the same problem.   Because often I run these meters to failure and I try to analyze why they fail, I want to be able to run the PCB open case.  The way the LCD, switch and battery are mounted to the case, it would make it difficult to work on.   I'm sure we will find out just how difficult.
In the original shootout video from Dave, he found out that twisting the Brymen was wreaking all sorts of crap on its screen. But perhaps it was a different model (so many OEMs/rebrands)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 08:43:19 pm
Ah, the twist test.   I showed my wife one of Dave's reviews and when he starts to twists the meter she busted out laughing.  It must have made an impression because months later when I told her I was planning to run one of Dave's production meters, the first thing she asked is if I was going to twist test it.    I need to start weight training.   :-DD

It seems very subjective. 
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on October 19, 2018, 09:35:54 pm
Ah, the twist test.

It beats me how people manage to put their phones in the back pocket of their jeans and then sit on them without breaking them.

When people do that with wallets all their credit cards come out bent.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 19, 2018, 10:09:58 pm
Take your best guess where you feel the Brymen will fail. 
I forgot about this question. IIRC from your tests, the well built meters tend to have the point of failure around the clamp diodes/transistors. Obviously that may change to the rotary switch due to the sheer space constraints.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 19, 2018, 10:31:04 pm
You have learned well.  :-DD   I have yet to damage a MOV with all the testing I have done.  I don't think I have ever damaged a surge rated resistor.   It's almost without failure the high high speed clamps that fail in the higher class meters.   Diodes, transistors, etc.  In the cheap meters, the piss ant  PTCs will commonly fail.  That's if the meter even has them.  Mostly its the main IC that does them in.

Dave's little UEI meter is a bit of an odd ball with that 15V diode check seeming to be the weak point when I looked at it.  A couple of KV will take the MUX first.  The UNI-T UT181A is just a bad layout which is really too bad.

Then we have that UNI-T UT90A.  That meter has more lives than a cat.  There's not enough clearances to things just break down and save the meter.   I have done everything I could to finish that meter off shy of building a higher powered generator.   

This little Brymen has the basics.  PTC, spark gaps, clamps, lots of slots in the PCB.  Yet True damaged four of them.   Something is very strange.. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 02:22:43 am
Joe, something you might want to look into with the bigger Brymens and maybe other meters too:


Also found another issue with the BM867s. If it’s sitting in series with the PA monitoring current it goes bloody mental when you key down. Fluke, fine. Keysight, fine. Hmm. This is why I haven’t dropped my review yet. I still like it but not for that.

Not sure what you've got to replicate RF keying or if you even want to give yourself a slight RF fry up.  :-\

What's this about?   I do normally sweep them to see if there are areas they are sensitive at.  Post a link or details about exactly what they are doing, their test setup, modulation.... 

I played around with a few of my meters once I picked up that Gossen at 10V/m, swept to a GHz. 
https://youtu.be/wYuzFtoHMqg?list=PLZSS2ajxhiQBTCU8Mq_i9jidT024A0dV6&t=840 (https://youtu.be/wYuzFtoHMqg?list=PLZSS2ajxhiQBTCU8Mq_i9jidT024A0dV6&t=840)
I know and watched all you did with the Gossen to get it immune to the near field and magnetiser sensitivity.
You can glean a little more about the circumstances here:
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1898834/#msg1898834 (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1898834/#msg1898834)

First, I don't recommend anyone ever try this at home with a meter they value.  Obviously, I have no way of knowing what they were doing. So let me try and set up a VERY bad and stupid thing to do.    :-DD

The Brymen BM869s was set to Amps and the signal generator set to 7MHz.   The meter placed DIRECTLY IN SERIES with a 50 ohm load.  The load has a tap going back to the DSO to monitor power.

The DSO is showing 746mV which is well over 100 Watts. Yes the load was HOT in short time.  :-DD

Of course I am not expecting the Brymen to throw up any useful data.   "If it’s sitting in series with the PA monitoring current it goes bloody mental when you key down."  What bloody mental means is anyone's guess.   The meter didn't reset,  show random data, power down and it didn't smoke. 

Maybe this is what damaged True's meters!
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 20, 2018, 11:53:36 am
It is useful when people  mention issues with meters and at least give the test conditions.
The uni-t 90A is the one have "fusible" tracks ?

About the Little Brymen, even it has the components and layout, does it have enought to withstand a ESD event?

The Amprobe functional test either it could be related to a batch issue, improper use of the meter, so you could get one good batch, do a proper use of the meter and get a different result from the test.


[Edit]

The Brymen in case is the BM27s and it is similar to the Ambrobe PM55A, but the supplied leads are different, and brymen has protective caps on the leads. Doesn't change the test but changes the aspect in terms of trying to do it more safe to hands... yeah...



Title: Re: Handheld meter electrical robustness testing.
Post by: Housedad on October 20, 2018, 12:11:10 pm
Ah, the twist test.

It beats me how people manage to put their phones in the back pocket of their jeans and then sit on them without breaking them.

When people do that with wallets all their credit cards come out bent.

Oh they do get bent. and cracked. and twisted. and dropped.  Don't let anyone fool you.

I have two daughters now in their early 20's. Add in my wife, and my sister.   I hate thinking about how many tablet,  Samsung phones and Iphone backs and screens I've replaced over the years or had to reform the corners and backs.  Off the top of my head, I think I have about 5 back straightener dies and the same # of corner straighteners in my 'phone box' of tools.  They can be rough on them sometimes.  I got tired of fixing them and their tablets all the time and told them to just pay for the insurance plan when they hit 20 years old.  They end up replacing them at least once a year on the plans.  Freedom is bliss.

The worse ones of all was the early Apple tablet about 6-7 years ago.  Seems that the ribbon cable connector on the main board to the screen would come off if you just looked at it.  I did not have hot air tools for reflow back then so I had to farm it out when it happened.  PITA.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 20, 2018, 02:05:28 pm
I was going to mention that as well. Cracked screens is a very common thing. When Apple released their slender phone (iPhone 6S, IIRC) the overall reaction was very negative with the bent phones. That's when people realized the blatantly obvious fact that putting a phone on the back pocket and sitting on it was actually a bad idea.

Fortunately for me, my wife is careful with her phone - although her last phone had a cracked screen, it only happened after many years of use and quite understandable as handling three year old twins is not an easy thing to do - an accident was bound to happen.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 02:54:35 pm
Because BD139 mentions using a BM867s, which I don't have,  I thought I would try this same test with a couple of other Brymen meters I have.   

The second one I looked at was the BM839.  Using the same setup, again the readings appear stable.   There was no power cycling or what I would consider "mental" behavior. 

***

Also, I should mention that the Brymen on the left is measuring the temperature of the 50 ohm load in the center of the heatsink.  There is a lot of air flow, but during short runs it will reach 100C.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 20, 2018, 03:43:44 pm
The uni-t 90A is the one have "fusible" tracks ?

It seems so.

https://youtu.be/aRuI_q_K5RY?t=411

Wow they really blew out of sight. I have now my anenginsh gone ... and it was related to a fall that it had ( 0.5 meter to floor). If you leave in the volt's position, let it power off ( at least its high impedance) and power on, if i push the box it would go crazy showing all segments or enter CAL mode :S It did that when i was performing some measurements on 230V isolated and puff..  I blame myself for using this meter on wood surface and not providing enoughtgrip... of course the there i grip in other meters...

[Edit]

Q3 blew up and and doesn't power on :(

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 03:56:01 pm
That's a bit odd as that clamp is not normally engaged.   Did you attempt to read the resistance of the 220V?   :-DD 

Actually, even if you did, I would have not expected it to fail like this.  All the ANENGs I looked at survived with that full rectified 220VAC line supplied to the meters while in each mode.   They actually held up better than many meters I have looked at.   

So what exactly did you do that caused this clamp to fail?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 04:03:22 pm
I repeated the 7MHz RF test on Dave's rebranded Brymen BM235.  What was interesting is as I increased the power level, the contrast changes to the point it washes out.   The readings were stable and there was no damage to the meter.    The last picture was just under 110 Watts at the load.    I changed over to DC current using my bench supply for a comparison.   

AGAIN, this is NOT something I would ever expect anyone to do.  I do not see this as a weakness of the BM235.  It's interesting to see how the meters behave but IMO there is little value in a test like this. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 04:16:13 pm
Just a closeup of how washed out the BM235 is compared with the BM869s.   If you watched some of the videos where I was testing a few automotive meters, I had attempted to use both the BM869s as well as the BM235 to measure RPM with the meters located very close to the test jig.   The BM869s was pretty solid throughout that test.   These are some pretty harsh tests.  We don't just hook a meter to a 9V battery and a 1K resistor and call that a review!   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 20, 2018, 06:34:47 pm
That's a bit odd as that clamp is not normally engaged.   Did you attempt to read the resistance of the 220V?   :-DD 

Actually, even if you did, I would have not expected it to fail like this.  All the ANENGs I looked at survived with that full rectified 220VAC line supplied to the meters while in each mode.   They actually held up better than many meters I have looked at.   

So what exactly did you do that caused this clamp to fail?

As i mentioned before i droped the meter some months ago from about 0.5m from the TV to the floor.   Since then when it was in sleep mode, in the Volts mode, if i awake with Select button it would do random stuff, like beeping, changing the decimal point, turning all digits and sometimes the backlit and CAL on display. Today i was performing some measurement on a 230V circuit isolated from mains and then the meter suddenly do random stuff and turns off.

I wish i was measuring resistance in the 230V so i could least have my punishment with precision, not with random stuff.   :palm:

I believe the fall must done something to the meter, on the PCB. There is a scrach on the lenses.  Anyway i assume the random bug was occuring in sleep mode circunstances and proceed with experiences , so ... i still blame myself 



100W and 7Mhz???? Is that an induction heater? Does the user was measuring an induction heater=
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on October 20, 2018, 07:11:38 pm
Tautech mentioned the RF issue I encountered being analysed in here. Some additional info:

1. PA was open board prototype.
2. BM867S was used to measure current hitting the drain of a FET through a 50uH loaf I nductor. Connected via Pomona banana leads. Mode Amps DC.
3. There was supposed to be a decoupling cap or two on the top end of the inductor. This was missoldered.
4. PA was delivering 25W out at the time.
5. “Mental” was weird readings and eventually it froze and had to be turned off.
6. My BM867S has crashed twice since I got it so this may be a problem with this meter.
7. Issue went away when I fixed decoupling, added Pi network LPF and Hammond enclosure.

I also found the PA was oscillating at around 120MHz as well as 7Mhz. This was resolved with a 10 ohm resistor in series with gate.

I didn’t delve too much further into this as I was more interested in building the PA at the time.

I suspect that there were extremely large voltage spikes (think SMPS) at the top of the inductor here.

Really I think this is a faulty unit at this point based on this behaviour and the other crashes.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 08:36:47 pm
Tautech mentioned the RF issue I encountered being analysed in here. Some additional info:

1. PA was open board prototype.
2. BM867S was used to measure current hitting the drain of a FET through a 50uH loaf I nductor. Connected via Pomona banana leads. Mode Amps DC.
3. There was supposed to be a decoupling cap or two on the top end of the inductor. This was missoldered.
4. PA was delivering 25W out at the time.
5. “Mental” was weird readings and eventually it froze and had to be turned off.
6. My BM867S has crashed twice since I got it so this may be a problem with this meter.
7. Issue went away when I fixed decoupling, added Pi network LPF and Hammond enclosure.

I also found the PA was oscillating at around 120MHz as well as 7Mhz. This was resolved with a 10 ohm resistor in series with gate.

I didn’t delve too much further into this as I was more interested in building the PA at the time.

I suspect that there were extremely large voltage spikes (think SMPS) at the top of the inductor here.

Really I think this is a faulty unit at this point based on this behaviour and the other crashes.

Thanks for the added details about your setup.   That other amplifier that I show is something I had put together from a kit can easily run up at 120MHz with more than 25W into a 50 ohm load.   The problem I see is that I don't have the exact same meter you have.   I tested the BM869s all the way up to 3GHz at 10V/m and it was very stable but that doesn't mean the BM867s doesn't have a design problem.   

If there is some other test you would like me try, feel free to ask.   
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on October 20, 2018, 08:49:06 pm
Please excuse the horrible typos in the previous post by me - damned iOS!

Thanks for testing this by the way. I'm not sure any further testing would be conclusive.

Out of interest I have another PA prototype in development which should kick out 50W this time. When I get to the same state of the build I will try again and see if I can isolate a cause.

Honestly though I'm not surprised if there are problems in these situations as they are mostly well outside what would be considered normal EMC situations. I certainly am not annoyed by the meter. On that front at least. It has a couple of annoying misfeatures.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 20, 2018, 09:02:55 pm
Hi there

Here is a photo of my setup test and the uni-t 50b , brymen bm235 are quite happy

But fortunally i got another unhappy meter about low battery. It just hanged :P with no reaction to buttons :P The uni-t ut-120c pocket meter that was offered in a workshop. Maybe it is in draining battery mode ...

https://youtu.be/GNOx79hEHmo

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 09:38:09 pm
Please excuse the horrible typos in the previous post by me - damned iOS!

Thanks for testing this by the way. I'm not sure any further testing would be conclusive.

Out of interest I have another PA prototype in development which should kick out 50W this time. When I get to the same state of the build I will try again and see if I can isolate a cause.

Honestly though I'm not surprised if there are problems in these situations as they are mostly well outside what would be considered normal EMC situations. I certainly am not annoyed by the meter. On that front at least. It has a couple of annoying misfeatures.

My spelling and grammar are both poor.  I typically won't take the time to proof read anything I post and only have myself to blame.  No big deal. 

I really don't know what a normal use case would be.  One reason I post my testing of handheld meters is because I'm sure I am not to only one who's electronic hobby extends past digital logic and 12V batteries. 

Let me know if you get a replacement meter and if it works any better or if you find the problem.
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on October 20, 2018, 09:48:35 pm
Will do. I'll post back here right away. Hopefully in the next couple of weeks.

If I find the same problem again I'll record all the details, stick it on youtube and talk to Telonic to get a replacement unit and see if that has the same "feature".
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 20, 2018, 10:03:48 pm
This video is for our long lost member True.   

https://youtu.be/0D_6uOFSgyY
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on October 20, 2018, 10:18:50 pm
I've actually got one of those. It's the "hamfest purchase testing meter". Will watch the video  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 20, 2018, 11:57:18 pm
Lost my bet on the little brymen, my aneng .. Very good for a pocket meter. brymen / amprobe would not let us down. at least didn't hang when battery is  low... Maybe was a bad batch that came to True

Those spark gaps really work. Ahhh 1 M Ohm :P



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 21, 2018, 12:04:45 am
The Keysight meter I ran also used spark gaps (GDTs) and it did not do very well in my tests. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 27, 2018, 03:42:04 pm
The Hioki DT 4252 also has a Gas Discharge Tube and performed really well, with added plastic near fuse holder to prevent arcing if i remember correct.
On the Amprobe It was funny to see GDT miniaturized and doing their job. Maybe they were properly tested before going to certification
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2018, 04:07:03 pm
The Hioki DT 4252 also has a Gas Discharge Tube and performed really well, with added plastic near fuse holder to prevent arcing if i remember correct.
On the Amprobe It was funny to see GDT miniaturized and doing their job. Maybe they were properly tested before going to certification
Yes, both that Hioki and the Gossen I have use GDTs and both did very well in my transient tests.    Then we have meters like the UNI-T UT181A that have a fair amount of circuitry including MOVs that fail with that gas grill starter.   The UNI-T is not a cheap meter and you would think that they would get it right but sadly they don't seem to have a good understanding on what it would take to harden a meter.    Odd as there are so many examples out there showing how.   

Then again, there are even more examples of weak front ends out there.   Some expensive and some dirt cheap.  Take your pick.   

My software for the 181A is in pretty good shape now and I plan to start putting together some sort of demo for it.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 27, 2018, 07:13:49 pm
Well about cheap it depends on which scale / type of the meter fits. The uni-t 181A is very similar to the fluke 287.. and the 287 costs a lot more, it is sluggish on plotting but it meets more safety then. Now the Keysight is not much cheap compared to equivalent meters , lets say fluke 115 / 117, [Edit the poor english, sorry ], the hioki ,brymen BM257s and fails so less value for the money.


The uni-t 181A heavly modified, with the software in labview over bluetooth must be something unique since it hasn't got a program for PC.

Now a different question. Did you perform a transient test after a drop on the aneng's?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 27, 2018, 09:57:46 pm
From what I understood from your sequence of videos hardening the UT-61E, it seems to me that both MOVs and GDTs are too slow for the spark produced by the igniter, leaving only the fast transistors/diodes and the severe increase in the input series resistance as the only effective lines of defense.

Taking that into consideration, a choice must be made by the manufacturers given the added resistance has negative consequences for the bandwidth.

Am I missing something?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2018, 10:02:39 pm
Well about cheap it depends on which scale / type of the meter fits. The uni-t 181A is very similar to the fluke 287.. and the 287 costs a lot more, it is sluggish on plotting but it meets more safety then. Now the Keysight is not much cheap compared to equivalent meters , lets say fluke 115 / 117, [Edit the poor english, sorry ], the hioki ,brymen BM257s and fails so less value for the money.


The uni-t 181A heavly modified, with the software in labview over bluetooth must be something unique since it hasn't got a program for PC.

Now a different question. Did you perform a transient test after a drop on the aneng's?

I should have been more clear.  I was not inferring anything about the features, quality or value, only the cost.  For me, cheap is $50 USD and less.   I've stated numerous times that I had never paid more than $50 for a handheld before starting these tests.   These cheap meters were never used for anything beyond basic automotive use in the garage or if I needed something avoid risking my bench meters.  I have always considered them disposable.

That said, when I started running the first $50 meters it was clear that one company stood out, even at that level. 

I would not say my UT181A is heavily modified, at least not compared with that KASUNTEST ZT102 or even that analog meter I tested.     Now if we were discussing that UT61E, that's heavily modified!   :-DD  Possibly the first handheld meter ever with an auto back light control.   

If you go back and watch that video where I drop test the ANENG and the KASUNTEST, you will find both were damaged long before they were dropped.   I had put them back together to try to get a feel for how they would hold up.  I don't think I ever dropped a working one.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2018, 10:12:17 pm
From what I understood from your sequence of videos hardening the UT-61E, it seems to me that both MOVs and GDTs are too slow for the spark produced by the igniter, leaving only the fast transistors/diodes and the severe increase in the input series resistance as the only effective lines of defense.

Taking that into consideration, a choice must be made by the manufacturers given the added resistance has negative consequences for the bandwidth.

Am I missing something?

Yes, you are missing something!!  You are correct in that the ESD, especially off that gun is VERY fast compared with the other transients I subject these meters to.  We are talking about 15Amps in about 800ps.    Compare that with rise times in the us.

I walked through the problem with the UT61E, showing the measurements I was making and how I made them and how I mitigated the ESD problem.   I did go on to change the design a bit as I continued to push the meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on October 27, 2018, 10:38:52 pm
Just a quick update on my problems with the BM867S. I tried the same set up again and the display was 100% stable this time. I have no explanation of what the issue is. I even set the bench out as close to what I remember I had it set up as and documented in my notebook. Power out was within 5% of original. Frequency spot on.

I will put this one down to quantum bogodynamics as my other half was in last time and isn't this time. She may have high bogon emissions.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 27, 2018, 11:18:04 pm
I have no explanation of what the issue is.
(...)
I will put this one down to quantum bogodynamics as my other half was in last time and isn't this time. She may have high bogon emissions.
Gremlins. Certainly Gremlins.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on October 27, 2018, 11:19:58 pm
Yes, you are missing something!! 
Uh... What exactly? The speed of the transient? I thought I had it covered on my post...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 27, 2018, 11:47:44 pm
Yes, you are missing something!! 
Uh... What exactly? The speed of the transient? I thought I had it covered on my post...
What does the speed, or better yet, let's say the rise time have to do with it?   What was it on the 61E that was damaged and why?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 28, 2018, 12:03:33 am
Just a quick update on my problems with the BM867S. I tried the same set up again and the display was 100% stable this time. I have no explanation of what the issue is. I even set the bench out as close to what I remember I had it set up as and documented in my notebook. Power out was within 5% of original. Frequency spot on.

I will put this one down to quantum bogodynamics as my other half was in last time and isn't this time. She may have high bogon emissions.

When I was a kid in my teens, one of my hobbies was amature radio.  I really didn't know a whole lot about anything back then but I had fun calculating my dipoles, hanging them up and then trimming them to the lowest possible SWR.   Our TV set, my scope, signal generator and even my meter was tube based.  So was my radio equipment.  There was a plate load and tune to set the power amplifier.    If the amplifier was not tuned correctly, I would get notice in the mail from some other amature who had heard my call sign on some other band that I wasn't even operating in.   Then I learned what harmonics and distortion are.   :-DD   I think my scope was good to a MHz, if that.   

Maybe your system was distorted enough that what you discovered is that the meter is actually sensitive in some other area.  Again, I swept the BM869s to 3GHz at 10V/meter and it was stable.  But you may have exceeded that by a fair amount.  If you run into it again and get a better idea of what is going on, just let me know and I can attempt to test it again over a wider frequency.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on October 28, 2018, 01:57:45 am
FWIW, there's a short but entertaining new BM839 review from Marco Reps showing-off ugly soldering on their mezzanine board.
https://www.youtube.com/watch?v=fRjXSbXZLmM (https://www.youtube.com/watch?v=fRjXSbXZLmM)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 28, 2018, 12:49:17 pm
Well about cheap it depends on which scale / type of the meter fits. The uni-t 181A is very similar to the fluke 287.. and the 287 costs a lot more, it is sluggish on plotting but it meets more safety then. Now the Keysight is not much cheap compared to equivalent meters , lets say fluke 115 / 117, [Edit the poor english, sorry ], the hioki ,brymen BM257s and fails so less value for the money.


The uni-t 181A heavly modified, with the software in labview over bluetooth must be something unique since it hasn't got a program for PC.

Now a different question. Did you perform a transient test after a drop on the aneng's?

I should have been more clear.  I was not inferring anything about the features, quality or value, only the cost.  For me, cheap is $50 USD and less.   I've stated numerous times that I had never paid more than $50 for a handheld before starting these tests.   These cheap meters were never used for anything beyond basic automotive use in the garage or if I needed something avoid risking my bench meters.  I have always considered them disposable.

That said, when I started running the first $50 meters it was clear that one company stood out, even at that level. 

I would not say my UT181A is heavily modified, at least not compared with that KASUNTEST ZT102 or even that analog meter I tested.     Now if we were discussing that UT61E, that's heavily modified!   :-DD  Possibly the first handheld meter ever with an auto back light control.   

If you go back and watch that video where I drop test the ANENG and the KASUNTEST, you will find both were damaged long before they were dropped.   I had put them back together to try to get a feel for how they would hold up.  I don't think I ever dropped a working one.   

Hello And thanks again for the clarification. For 50 "doll" mark it comes to the 101 or the Am510. I believe when you talked about the modifications about the ut61e you also mentioned the uni-t 181A and it sound  was more difficult on one of the videos :

https://youtu.be/cMutvk_6xhY?t=2541

The piezzo grill starter may have low energy but it is a ultra fast spike and the clamps must be prepared for it, if any...

My question about the drop is that my aneng has failed during monituring 230V AC isolated, due to droping from my TV stand to the floor (0.5m height) front facing which result in random mode changing / enter CAL mode when wake up from SEL button.

 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 28, 2018, 02:14:37 pm
Well about cheap it depends on which scale / type of the meter fits. The uni-t 181A is very similar to the fluke 287.. and the 287 costs a lot more, it is sluggish on plotting but it meets more safety then. Now the Keysight is not much cheap compared to equivalent meters , lets say fluke 115 / 117, [Edit the poor english, sorry ], the hioki ,brymen BM257s and fails so less value for the money.


The uni-t 181A heavly modified, with the software in labview over bluetooth must be something unique since it hasn't got a program for PC.

Now a different question. Did you perform a transient test after a drop on the aneng's?

I should have been more clear.  I was not inferring anything about the features, quality or value, only the cost.  For me, cheap is $50 USD and less.   I've stated numerous times that I had never paid more than $50 for a handheld before starting these tests.   These cheap meters were never used for anything beyond basic automotive use in the garage or if I needed something avoid risking my bench meters.  I have always considered them disposable.

That said, when I started running the first $50 meters it was clear that one company stood out, even at that level. 

I would not say my UT181A is heavily modified, at least not compared with that KASUNTEST ZT102 or even that analog meter I tested.     Now if we were discussing that UT61E, that's heavily modified!   :-DD  Possibly the first handheld meter ever with an auto back light control.   

If you go back and watch that video where I drop test the ANENG and the KASUNTEST, you will find both were damaged long before they were dropped.   I had put them back together to try to get a feel for how they would hold up.  I don't think I ever dropped a working one.   

Hello And thanks again for the clarification. For 50 "doll" mark it comes to the 101 or the Am510. I believe when you talked about the modifications about the ut61e you also mentioned the uni-t 181A and it sound  was more difficult on one of the videos :

https://youtu.be/cMutvk_6xhY?t=2541

The piezzo grill starter may have low energy but it is a ultra fast spike and the clamps must be prepared for it, if any...

My question about the drop is that my aneng has failed during monituring 230V AC isolated, due to droping from my TV stand to the floor (0.5m height) front facing which result in random mode changing / enter CAL mode when wake up from SEL button.

If we talk about the changes made to the PCB just for the sake of getting the UT181A and the UT61E to pass me ESD test, then yes there  was a lot more involved in 181A.  As I said in the video the UT61E required a single cut to the PCB was all (again, just for the ESD. NOT for all of the other modifications I made to the meter).  Your original post is not specific to ESD.  It's a general statement about the "heavly modified" UT181A which when compared with the UT61E, is not. 

Yes, the gas grill starter is a fairly fast spike with very low energy compared with other transients that I expose these meters to.  I still have a hard time believing that it would damage ANY meter made today.

Your drop test does not explain that cracked transistor.  You may think it was random and had something to do with a calibration mode but I would put my money on the selector switch being in the wrong position and applying a high voltage.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 28, 2018, 10:23:12 pm
The 100mV means 1A on the plot?

The drop was an accident. I was checking the voltage on a SBC (Small Board Computer ) connected to TV, i pulled the leads a little bit and then it dropped in the floorr. The front panel got a scratc but nothing special. I tested the multimeter and it seemed fine. But sometimes in Volt mode and Sleeping, when i press SEL to wake up, sometimes it would go crazy jumping modes on it's one or going to CAL mode. If i press the multimeter it would switch more frequently.

The randomness i was talking is about the modes it would switch and would hang on CAL mode.

Eventually i  still kept using on a AC project and assume that it would only be tripped when in sleep mode, but it behave bad while measuring the AC Volts, then turned off and never came back again. I can open further if there was any damage on the contacts from the rotary switch, but it was all the time in Volts mode.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 28, 2018, 10:45:22 pm
Here are some photos of the pads for the rotary switch with some sort of grease, also one trace in the middle is pretty scuffed. This is one year of use...
 Also the lens were scratch from the fall are available.

The spring contacs on the rotary switch are like brand new, without wear.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 28, 2018, 10:53:13 pm
Here are some photos of the pads for the rotary switch with some sort of grease, also one trace in the middle is pretty scuffed. This is one year of use...
 Also the lens were scratch from the fall are available.

The spring contacs on the rotary switch are like brand new, without wear.

The image of the rotary switch...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 29, 2018, 11:29:47 am
Thanks for refreshing the memory. That pulse is hard to capture on current measurement.
The ESD gun looks more harmfull than piezzo grill starter since it approaches the IEC test and again uni-t 61e modified passed that test. Maybe uni-t has corrected that in newer DMM's.

However the Amprobe pm55a, which i bet that would fail on that test, it ran without issues and got beyond the 6kv. By the way did you managed to produced the bug reported by True after the video?




Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 29, 2018, 04:43:05 pm
Thanks for refreshing the memory. That pulse is hard to capture on current measurement.
The ESD gun looks more harmfull than piezzo grill starter since it approaches the IEC test and again uni-t 61e modified passed that test. Maybe uni-t has corrected that in newer DMM's.

However the Amprobe pm55a, which i bet that would fail on that test, it ran without issues and got beyond the 6kv. By the way did you managed to produced the bug reported by True after the video?

I knew a guy who tried to measure the output of an ESD gun directly with a DSO.  It didn't work out so well.   :-DD The standards cover how to make the measurement.   

I've yet to have a Brymen product perform poorly against my tests so seeing the pocket meter not having any problems with the newer low voltage generator was not much of a surprise. 

I have continued to try other tests with the pocket meter but have yet to see a problem.  True talks about the low battery in all cases.  Maybe they installed LIRs to replace the CRs.   The manual clearly calls out CRs in numerous places but that doesn't mean that True followed the manual.   I don't know if the added voltage from an LIR could damage it or not.   The manual is just clear about what to use, not about what happens when you don't follow the instructions.   :-DD 

Maybe one day they will post again and we can get a few more details about what happened with all four of their meters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 29, 2018, 05:55:08 pm
Wow nice detail on the battery , It's like installing lithium AA instead of the Alkaline or NIMH of this size, but the eevblog BM235 manual  calls out for that situation.

About my meter looks like one of my brothers use it to measure the voltage of the flyswatter and it said it was doing OL all the time and switched to other off position while the thing still on and leads plugged  :palm: . i. , before i ran the 230V ac test... I thought it was the fall but now i have the oportunity to offer one of my old meters, the uni-t 50b, teach more stuff. All bets are off for now.... :-DD





Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 29, 2018, 10:27:57 pm
I could try installing one and see if there are any long term effects.  If it damages the meter, it doesn't mean that's what happened with all four of True's meters.   It also doesn't mean there is anything wrong with the design.  I wouldn't expect to be able to use a different battery than the manufacture calls for without damage.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 30, 2018, 12:33:22 am
Well there always the chance of flipping the polarity , but four in a row would be a bad play.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 30, 2018, 12:42:33 am
Seems like Voltlog mentioned that it had reverse protection.  I think they shunt it with a diode.  Still I know I didn't test it.  It would be pretty bad though as the meter is marked in at least two places, plus the manual.  Still....  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 30, 2018, 11:19:46 am
About my meter looks like one of my brothers use it to measure the voltage of the flyswatter and it said it was doing OL all the time and switched to other off position while the thing still on and leads plugged  :palm: . i. , before i ran the 230V ac test... I thought it was the fall but now i have the oportunity to offer one of my old meters, the uni-t 50b, teach more stuff. All bets are off for now.... :-DD

on the left side of the battery holder is a supressor diode - see if it's shorted or try the meter without it.
i got an aneng from someone who did something stupid, and that was blown.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 30, 2018, 05:00:23 pm
From what I remember, that TVS was for the current input and I thought it was on the backside of the switch.   :-//  I may have scribbled out that circuit when I made the video where I had modified the meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 30, 2018, 08:26:58 pm
Are you refering to the Q3 that was blown or the TVS on the current input? I can probe later the Q3 if it is shorted and maybe take it out.

(http://[url=https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=552092]https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=552092[/url])

Well i have probe Q3 and Q4 are shorted.... maybe i'll take out later and fingers crossed
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 30, 2018, 08:51:59 pm
i was refering to the tvs,
people who dont read instructions dont know the current mode is limited to about 50v
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 30, 2018, 09:58:06 pm
Yes in most cheap meters its more or less 30 Vrms on the current side. I've removed the Q3 / Q4 and the TVS., plug the batteries, no meter.

The TVS shows no voltage in diode mode in both directions,  aka O.L. meanwhile i've ordered a replacement meter... one of the most cheapest true RMS meters for measuring voltages up to 600V, but i'm using max 230V. Bet you're guesses and it is similar to one that joe smith has tested :P
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on October 30, 2018, 10:05:52 pm
Yes in most cheap meters its more or less 30 Vrms on the current side. I've removed the Q3 / Q4 and the TVS., plug the batteries, no meter.

There is no voltage limit when measuring current, even on cheap meters. The TVS diode is there to protect the current shunt during over current conditions until the fuse blows.
If the fuse blows it may not be able to break the current and higher voltage may damage the meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 30, 2018, 10:27:00 pm
At least on the manual on the uni-t 50b it calls for 30Vrms maximum.input .. but this is a meter with unfused A and fused mA , so it gets even worse...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 30, 2018, 11:58:36 pm
Demonstrating my software for the UEI / EEVBLOG 121GW and the UNI-T UT-181A.    This video also contains a test that 001 and Fungus had requested using high voltages, a spark gap and Vaseline.   :palm:   For future reference, that thread may be found here:

https://www.eevblog.com/forum/testgear/can-i-grease-my-dmm-selector-with-silicone-oil/ (https://www.eevblog.com/forum/testgear/can-i-grease-my-dmm-selector-with-silicone-oil/)

https://youtu.be/e_YzwO62feQ (https://youtu.be/e_YzwO62feQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 31, 2018, 12:50:39 am
Now it is using my old uni-t 50b and read the manual before using it. They are the acessible meters.
The one that i've got is the uni-t ut139A , the worst of the 139 line. At least it has ceramic fuses for the claimed voltage, it has enough grip and simple to use. It will be out of reach for modifications.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on October 31, 2018, 08:47:01 am
Just to be clear: I didn't request Vaseline, that was 001.  I just suggested the spark gap test.  :D

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 31, 2018, 09:37:26 am
I only watch the video till the labview interface because it was too late and damn, very nice. Very Good algorithm for using the A/D. looks like the BLE interface may fit the uni-t 81b scope. I've contacted uni-t but no answer yet.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 31, 2018, 11:08:43 am
Just to be clear: I didn't request Vaseline, that was 001.  I just suggested the spark gap test.  :D

If that's a concern for you, next time perhaps think more, post less? 

Simple test: Make a spark gap, put Vaseline on it, see if it stops sparking.  :popcorn:

(and if it stops, how much higher do you need to go to get it to spark again?)

I provided a link to the thread in the description for those wanting to read what's been posted and follow along.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on October 31, 2018, 11:17:08 am
Just to be clear: I didn't request Vaseline, that was 001.  I just suggested the spark gap test.  :D

If that's a concern for you, next time perhaps think more, post less? 

Not a problem for me. I think it was a good test, worth documenting.

So
I want to protect selector from arc at lamels
Is silicone best isolator than air?

If you think there might be an arc then grease isn't the answer (and probably won't help).

Change the operating procedure, wear protective gear, get a better meter if necessary.

I was wrong, it helped.  :-//

(on a simple spark gap)

...but I stand by the "If you think there might be an arc then grease isn't the answer" part.

(and if you're gonna apply grease, use grease that's designed for the job)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on October 31, 2018, 11:32:08 am
I was wrong, it helped.  :-//

I should probably qualify that:

a) Putting a big blob of non-conductive grease on a spark gap will obviously help. This was demonstrated.

My concern is that if you put it on the wiper contacts of a multimeter then it's going to get spread very thin after you turn the selector a few times. How effective will it be then? That's a lot harder to quantify - it depends on the meter.

b) The OP in the other thread seems to think a random applications of grease will make his meter safer. I don't share that view at all. I think he should buy a properly designed meter, one that won't arc in the first place.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 31, 2018, 11:42:52 am
Now it is using my old uni-t 50b and read the manual before using it. They are the acessible meters.
The one that i've got is the uni-t ut139A , the worst of the 139 line. At least it has ceramic fuses for the claimed voltage, it has enough grip and simple to use. It will be out of reach for modifications.

I've not looked at the 139A.  Just in general have not been very impressed with the UNI-T product line.  I still like that 210E clamp (as a clamp only). I'm not aware of anyone I know who bought one having any problems with it yet.  The 181A could also be a very nice meter with a few changes.

The uni-t 139A it should have in theory the same input protection as the 139C, but with less functions, counts, etc. The 210E  clamp meter was out of stock and i have already one clamp meter.  So far i'm quite happy with Eevblog BM235 since it has plenty of functions, good input protection , nice digits, decent backlight and battery life and that i use to monitor AC current which it is more accurate.

Edit Here is a picture of the actual meter with D.U.T.
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 31, 2018, 01:14:42 pm
did anybody seriously think putting PETROLeum jelly on a spark-gap or switch would be a good idea??  :palm:
it's one of the primary ingrediants of a molotov coctail!!
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 31, 2018, 03:23:39 pm
That would ignite the video of joesmith a lot, with possible flames :S Even the 230V 6V isolated mains does a little spark between 1mm or less on D.U.T. which is dangerous .
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on October 31, 2018, 05:32:39 pm
There are many long, religious threads about lube in DMM rotary switches.
I'm experimenting with Krytox GPL 105. (https://www.miller-stephenson.com/chemicals/lubricants/krytox-lubricants/krytox-gpl-series/krytox-gpl-oils/)

It's basically liquid Teflon in a fluorinated-base. Used in Aerospace and MILSPEC.
No silicones, no petroleum, non-reactive, non-flammable. It's the best lube out there, but very expensive. Doesn't evaporate.
Oddly enough, it's used by car dealerships to stop weatherstripping from squeaking due to body flex.

Krytox 105 is a medium thickness oil and I think 205 is a grease.

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on October 31, 2018, 05:33:22 pm
they could spray the switch area with teflon and be done with it.
i cant see any point though.


grease actually makes sense.
if you think about it, the contact area is a thin line down the center of the pads,
so if you increase the gap from the space between the pads to the space between the centerline of the pads then you increase the breakdown voltage.
[in theory]
Title: Re: Handheld meter electrical robustness testing.
Post by: 001 on October 31, 2018, 07:19:32 pm
Hi!

What is "High Voltage" actually?
Is it 200V, 600V or 1200V? DC or AC? What freq?
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on October 31, 2018, 07:26:20 pm
What is "High Voltage" actually?
Is it 200V, 600V or 1200V? DC or AC? What freq?
https://en.wikipedia.org/wiki/High_voltage#Definition
Title: Re: Handheld meter electrical robustness testing.
Post by: 001 on October 31, 2018, 07:29:57 pm
What is "High Voltage" actually?
Is it 200V, 600V or 1200V? DC or AC? What freq?
https://en.wikipedia.org/wiki/High_voltage#Definition

Wow! But I mean DMM halaxy
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on October 31, 2018, 10:21:36 pm
High voltage in DMM,  would be around what manuals ( Safety Information ) of  describe on the first pages to be aware of probe techniques to prevent hazards, starting at 30Vrms or 60Vdc .  Tthe meter could have a LED  of the HV or starts beeping a lot...

 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 31, 2018, 11:03:49 pm
It's the best lube out there, but very expensive.

Like I haven't heard that one before.   :-DD 

When I see something hold up as well on that 50,000 cycle life test than the Fluke 17B+'s dry contacts, I will surely let people know.  I would rather see a properly designed switch than spend my time searching for the world's best lubrication. 


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 31, 2018, 11:12:35 pm
High voltage in DMM,  would be around what manuals ( Safety Information ) of  describe on the first pages to be aware of probe techniques to prevent hazards, starting at 30Vrms or 60Vdc .  Tthe meter could have a LED  of the HV or starts beeping a lot...

Quote
The numerical definition of "high voltage" depends on context.
I tend to agree with their opening sentence.  In the context of a handheld DMM normal use, I lean more towards what you wrote and the wiki section on safety. 

When I test meters, I talk about my low voltage transient generator.  It's 6KV which may seem like a lot but in the context of the transients I can generate, it falls way short of the 15KV I tested the Fluke 107 at.   
Title: Re: Handheld meter electrical robustness testing.
Post by: wasyoungonce on October 31, 2018, 11:48:31 pm
......Krytox GPL 105...................Used in Aerospace and MILSPEC..................

Good old Krytox...the only stuff we were allow to use on Aircraft oxygen systems.  Not cheap though.  But I suspect the Military sales markup was a few 1000%
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 01, 2018, 01:18:52 am
High voltage in DMM,  would be around what manuals ( Safety Information ) of  describe on the first pages to be aware of probe techniques to prevent hazards, starting at 30Vrms or 60Vdc .  Tthe meter could have a LED  of the HV or starts beeping a lot...

Quote
The numerical definition of "high voltage" depends on context.
I tend to agree with their opening sentence.  In the context of a handheld DMM normal use, I lean more towards what you wrote and the wiki section on safety. 

When I test meters, I talk about my low voltage transient generator.  It's 6KV which may seem like a lot but in the context of the transients I can generate, it falls way short of the 15KV I tested the Fluke 107 at.   

Humm  i was out of context maybe or forcing it, assuming what comes first in the manuals and forgot the IEC standards , CAT ratings  that are also mentioned and adds to another section of high voltage surge.

About lubricants i don't have a concrete opinion, but follow the recommended stuff as in mechanical parts by the brand
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on November 01, 2018, 02:27:17 am
It's the best lube out there, but very expensive.
Like I haven't heard that one before.   :-DD 
When I see something hold up as well on that 50,000 cycle life test than the Fluke 17B+'s dry contacts, I will surely let people know.  I would rather see a properly designed switch than spend my time searching for the world's best lubrication.

Strange, it wasn't dry (on the PCB) for the old 87:
https://www.eevblog.com/forum/beginners/lube-dmm-selector-switch/msg1248833/#msg1248833 (https://www.eevblog.com/forum/beginners/lube-dmm-selector-switch/msg1248833/#msg1248833)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 01, 2018, 07:43:48 am
It's the best lube out there, but very expensive.
Like I haven't heard that one before.   :-DD 
When I see something hold up as well on that 50,000 cycle life test than the Fluke 17B+'s dry contacts, I will surely let people know.  I would rather see a properly designed switch than spend my time searching for the world's best lubrication.

Strange, it wasn't dry (on the PCB) for the old 87:
https://www.eevblog.com/forum/beginners/lube-dmm-selector-switch/msg1248833/#msg1248833 (https://www.eevblog.com/forum/beginners/lube-dmm-selector-switch/msg1248833/#msg1248833)
If we are talking about Fluke,  I am guessing that the grease is being used as a lubricant and not to increase the breakdown voltage.  I assume the meters are designed not to arc by design (creepage, clearance).    Again, a GUESS.  I am not presenting this as a fact! 

It's possible that the 17B+, being a newer design has a better switch design than the 87.  Better materials, spring tension, surface area, contacts, thickness......  The parts making up the 17B+ switch assembly even after the 50,000 cycles are still all in very good condition. 

You would think the 87V being what some consider the best meter mankind has ever created,  would have the best switch design.  Again it uses dry contacts.  19:00 - 27:00 may be of interest. 

https://youtu.be/dQPcAs0EEqY?t=1099 (https://youtu.be/dQPcAs0EEqY?t=1099)

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 01, 2018, 12:47:02 pm
Well the fluke 87V is one of the most known and referenced meters , for it's functions, but considering the best meter of mankind has ever made maybe it stay's on the time when it first got into market.  It's a very subjective matter.

Now there are more brands, and meters like brymen BM867s , Fluke 117+, keysight U1282A for example that have unique build quality features into it. I'd like to grab the keysight, put on it on a bag to my back, swim with that meter and of course let it dry a little bit to test measurement. 

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 05, 2018, 10:49:55 pm
Hi i found another feature or bug in one of my meters, it is the clamp meter uni-t 204A.. the one that is not true RMS... if it enters sleep mode and you wake up with any button it doesn't sleep anymore.... The other meters like bm235, ut139A they enter sleep mode ever ,and after awaken by buttons.

It is still on for hours doing the job of discharging the rechargeable 9V battery...  in volts range of course... Maybe i should open another thread....

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 28, 2018, 07:01:56 pm
Three new handheld DMM videos in the works. 

With True never posting again, I had decided to run even more tests on the Brymen pocket meter.   That has been going nonstop since the first video was made.  I plan to repair one of the meters we damaged a long time ago and see if I can harden it.  And finally, I've had a few people requesting new meters be ran.  I've been watching reviews and picked one out.   All the reviews I saw for it from the big channels give it the old thumbs up.   Sorry, it's not the 121GW.

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 28, 2018, 10:18:20 pm
Hey new meters to be put on the run :P Are some anengish types?

Did you ever tester one of the Non-Contact Voltage Pen tester? Some of them claim CAT IV .... CATII .. 1000V or none..

Here are some examples:

CAT II:

https://ebay.us/bcEHuF

CATII:

https://ebay.us/xF6EeJ

CATiV ( Fluke):

https://ebay.us/qEjMiQ


There are lots of models.... and a mixed CAT ratings on them... and of course there is always a aneng...:

https://ebay.us/qEjMiQ

... with a proper CAT rating :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2018, 02:49:50 am
Hey new meters to be put on the run :P Are some anengish types?

This will be a brand I have not looked at yet.  There are many reviews and tear downs of it.  Lots of positive feedback.  Thing is, my transient generators don't seem to care about all of that.   

Did you ever tester one of the Non-Contact Voltage Pen tester? Some of them claim CAT IV .... CATII .. 1000V or none..

There is a link to an on-line spreadsheet in the very first post of this thread which contains data for every handheld meter I have looked at.  If it's not on that list, I have not ran it (except for one or two exceptions).   

How would you propose I would test these non-contact testers?    You know who would be a good person to run them would be John Ward.  He does a fair amount of electrical testing.    If PhotonicInduction were still making content, he would be another good source. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 29, 2018, 03:11:46 am
Hey new meters to be put on the run :P Are some anengish types?

This will be a brand I have not looked at yet.  There are many reviews and tear downs of it.  Lots of positive feedback.  Thing is, my transient generators don't seem to care about all of that.   
A certain Japanese manufacturer?  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2018, 03:25:57 am
That's getting too specific.  You don't want to spoil the fun do you?   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 11:29:41 am
Hummm japanese meters... OK. i got it. :P  I saw some videos about on John ward about the voltage pen on the context of proofing no live connection as dubious. Photonic induction would pop them as in the video where he obliterates the screw pole tester and test a good isolated screw driver with a lot of voltage i believe 50Kv was the break point.

I don't see any non-contact voltage pen on the spreadsheet...

About the question about testing this voltage probe would be applying a transient between the probe point / tip and the casing or battery compartiment GND which should be high impedance  towards to the tip.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2018, 12:38:41 pm
There isn't any exposed metal on the tip or the battery compartment.   Are you wanting to know if the plastic is a good enough insulator?   There are a LOT of reviews for them and some decent documents.   

I'm not an electrician and have never used one, nor have I ever had the need.  I am also not setup to do any sort of electrical testing.  Another member asked once about testing surge protectors and small USB chargers.   I think there is still a fair bit of confusion about what is required to run some of the actual mains tests and how they compare with what I show.   I think if I ran any sort of tests on them, people would once again somehow equate it to safety of view it as some form of validation of the products certifications. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 01:00:51 pm
Thanks for the clarification. The battery compartiment is acessible for the user . I just received one. It's not about insulation but to know how a CAT rating is aplied  / tested to these devices if you or someone have any knowledge in this matter and the diversity of CAT ratings.  They are become more used on electricians here as well in home use. 


If persons equates things they can also read the FAQ which is well documented :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2018, 01:36:09 pm
Yes, the battery compartment is certainly accessible to the user, just like with any handheld meter.   Having the battery area exposed while using a device on the line may win you a Darwin award.   

I would imagine they are common here as well in the electrical world.  They would be much safer than jamming metal probes in things.  John Ward had made a video titled "Proving Dead - Mains Electricity".    May be worth watching.   Not being an electrician, I will leave the training videos to much more qualified people. 

Sadly, having documents available does not mean that people will read them. It's the same for the long videos.  I try (admit, not very good at it) to condense a lot of material into these long videos.  On average, a person will watch maybe 10% of it.   That's not a problem for me but I had one person argue with me for several posts about a video.  When they were unable to skim the 40-60 mins and find a specific part they became upset.   I have a low tolerance and may have flushed them.    :-DD
 
Two of the most common questions are: Have you ran ____? and Would you recommend ____?   No escaping those two.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 02:40:33 pm
Too bad not seeing the hole video and going for discussion without all the required data. The notepad  would do a good job on taking notes.
The first question may be become more popular to have you run these meter before or these product as i did with the NCV Pen's  . About recomendation yes a lot of people will ask recomendations due to the test made and clarification, but again it is described on the FAQ about recomendation. I remember "you saw what i end up buying"  on a meter , i believe on the uni-t 139c part II video.. not a recomendation but definitly a good choice for a meter..

I watched that video of John Ward , very good, and i quite liked the Fluke T110 Voltage tester, but it is a different product (maybe is most the proper one). About battery that is  correct for all multimeters, volt testers , more a suggestion / idea of how performing  CAT testing in DYI between GND and NCV probe, but with an NCV product like that how can CAT rating can be done? Maybe they have a proper test JIG for that kind of devices. With multimeter you use the banana plug , or adapters to positive and negative and...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2018, 06:11:40 pm
Maybe they have their own standard.  You say you bought one.  Do they refer to any IEC standards on the packaging or manual?  This would be a good place to start if you want to learn more about how they are tested. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 08:19:21 pm
Well no manual supplied , no packaging. in the pen says to read the manual.... yeah that what i get.... the cheapo way, but i believe that is somewere the aneng model .:

(https://elenxs4.com/getImage.php?p=1234596&sku=GJ_GJ2818-00-X19.jpg)

The one i've bought is this.:

(https://i.ebayimg.com/images/g/wOEAAOSwTM5Y0F~H/s-l1600.png)
Title: Re: Handheld meter electrical robustness testing.
Post by: Vtile on November 29, 2018, 08:26:52 pm
I have one (4€) which shows that my wall mirror does have mains potential in it as does my work desk.  :-DD  :palm:
Title: Re: Handheld meter electrical robustness testing.
Post by: glarsson on November 29, 2018, 09:08:18 pm
I have one (4€) which shows that my wall mirror does have mains potential in it as does my work desk.  :-DD  :palm:
Free energy!
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 09:14:08 pm
Well this one doesn't do that and doesn't work well on my sockets . I have to use a UK to EU(Type G to F ??? blob:https://www.dropbox.com/1b062708-409e-4ccc-b9c3-485785168d62 )  adapter to work on the plugs  :-DD It doesn't trip with DC voltages... Now its time to perform a test on a Isolated transformer , 220 VAC 6VA .
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 09:27:26 pm
Well this one doesn't do that and doesn't work well on my sockets . I have to use a UK to EU(Type G to F ??? blob:https://www.dropbox.com/1b062708-409e-4ccc-b9c3-485785168d62 )  adapter to work on the plugs  :-DD It doesn't trip with DC voltages... Now its time to perform a test on a Isolated transformer , 220 VAC 6VA .

It trips on one of the conductors on the isolated side and on the isolated side there is a capacitice dropper that feeds an opamp and also provides the AC signal to it and that signal goes to optocoupler, into a 555 :P On  the 555 side doesn't beep but on the rest of the circuit it beeps :P. The 555 is also isolated with SMPS...

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 29, 2018, 09:29:43 pm
malagas, I am almost sure that CAT II in this case is probably arbitrary to restrict the usage scenario to low voltage environments.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=584033)

I have a Fluke LVD2 and it says straight CAT IV 600V
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=584039)

Although it has several usage warnings.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=584045)

I would imagine they are common here as well in the electrical world.  They would be much safer than jamming metal probes in things.  John Ward had made a video titled "Proving Dead - Mains Electricity".    May be worth watching.   Not being an electrician, I will leave the training videos to much more qualified people. 
I watched this video when it was out and John got a lot of flak due to his dissing of screwdriver testers. I agree with the criticisms; the contactless testers can be quite unreliable (if not more) than the screwdrivers. I have encountered zillions of scenarios where false negatives were given by the contactless.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 09:40:37 pm
Thanks for the enlightment.  I'm using this at the sockets, power cords from appliances and a project development..

I have heard about false positives which for proving live shut off can be inacurate, but has the safety aspect of the non contact. Again i liked the fluke t110 and John Ward did a video about the recalls of this device, when he probes the live with the main probe without any contact.  :

https://youtu.be/F_Hqp5gSYrU?t=470

I'll see if i can get some information about the tests in safety regarding to this devices
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 29, 2018, 10:09:42 pm
Thanks for the enlightment.  I'm using this at the sockets, power cords from appliances and a project development..
For this usage the contactless should be fine. Just beware if you are trying to probe through very thick or shielded connections - the contactless may not catch the voltage.

I have heard about false positives which for proving live shut off can be inacurate, but has the safety aspect of the non contact.
Since you mentioned, all my contactless gadgets (the LVD2, the Keysight U1282A, the Surpeer AV4) flicker/beep when I move them over or towards a metal surface - a disturbance in the magnetic field probably causes an induced current on its sensor.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 29, 2018, 10:25:11 pm
i belived i've posted that in a comment above and yes it doesn't work on the F type sockets here. I have to use the G type ( UK) adapter to do a proper test. But thanks to remember.

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2001089/#msg2001089 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2001089/#msg2001089)

The other pen testers recommends previous probation before testing and yes NCV relies on change on magnetic field.. not 100% accurate indeed.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2018, 11:19:47 pm
This looks like a decent forum to join if you are interested in electrical work and safety.  Reading through some of the threads, looks like many are professionals.   Then again, this thread has pictures of cats.  Hard to beat that.

https://brainfiller.com/arcflashforum/index.php

First hit on Google: https://images.homedepot-static.com/catalog/pdfImages/70/70de1fda-51a3-4ca1-bc53-53b45618926a.pdf
Looks like they are held to the same set of standards.   I have no idea how they actually conduct the tests.

Here is a good read:
https://brainfiller.com/arcflashforum/viewtopic.php?f=10&t=2203

Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 29, 2018, 11:40:33 pm
I've had no problems using non-contact volt alert sticks when doing home electrical work. I touch the detector to live conductors and it lights up and beeps. I isolate the circuit and the same conductors no longer beep, thus verifying that I have opened the right breaker.

False alerts don't bother me. For example my iPhone detects positive when it is plugged in and charging. But this is not a relevant use case for the voltage detector so I see no reason to worry about it.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 30, 2018, 12:12:04 am
Didn know they called wiggies... and the impact on the semiconductors... PLC's from that forum and i subjected the project to that pen  :palm:

And exploding wiggies. ??? yeah that makes me question more the CAT ratings :P or photoninduction work ..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 30, 2018, 12:17:46 am
I thought a wiggy was the old clacker with a solenoid in it. 

**********

Yep.  Amazed what you can find with a modern search engine and a couple of  words.

https://www.quora.com/How-does-a-Wiggy-Tester-differ-from-a-multimeter (https://www.quora.com/How-does-a-Wiggy-Tester-differ-from-a-multimeter)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 30, 2018, 12:35:23 am
If you search for images or catalogues ohh man... it goes to home depot.. and finally we got some wiggies:

http://dicimo.com/blog/remodeling-your-kitchen-should-you-get-a-dishwasher-pretty-tips-ideas/ (http://dicimo.com/blog/remodeling-your-kitchen-should-you-get-a-dishwasher-pretty-tips-ideas/)

This looks like the one that was on the head.... Or maybe this one:

https://www.amazon.co.uk/Klein-69115-Solenoid-Voltage-Tester/dp/B000KII9SM (https://www.amazon.co.uk/Klein-69115-Solenoid-Voltage-Tester/dp/B000KII9SM)

[More Editing...]

At least the product above says wiggy :P
Title: Re: Handheld meter electrical robustness testing.
Post by: Towger on November 30, 2018, 08:23:06 pm
It is easy to destroy a Fluke Voltalert, you just use the batteries which came with it.  They will eventually leak without warning (but still work) ending in a dead Fluke.

Phontonic is still around, but pulled his last couple of videos.

https://youtu.be/vlO5Hugwn2A
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 30, 2018, 08:57:15 pm
Well the battery leak also applies to other aparatus or drop it from higher place :or water divingP Very impressed with the video of king and taylor...  :-DD , looks like a salesman :P

Let's see if there is any information about CAT testing on this NCV's Pens...

By the way no manual in pdf for my specific pen from the seller, but the one from the klein tools serves well.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 07, 2018, 10:03:50 pm
Hi

Is this multimeter also under your test Surpeer AV4?

"Vbe 048: 20000 contagens por $13?"

20000 counts for $13 ? It's not going to take much longer in the video  :-DD

https://www.youtube.com/watch?v=xSLJi9Tt--k (https://www.youtube.com/watch?v=xSLJi9Tt--k)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 07, 2018, 10:10:53 pm
joeqsmith would have a field day with this meter; starting at about 33:30 I put the non-volt ranges through a ring generator (90VAC, 20Hz, but the load probably took it down to about 40VAC) and the meter goes completely haywire.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 07, 2018, 10:25:01 pm
I have one pocket meter ( UT120C) which trips in Hz mode when plugging the lead suddenly or do any tiny friction in the 230V 50Hz AC socket or even in isolation transformer, same voltage , freq, 6VA . Thankfully this was an offer...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 07, 2018, 10:39:58 pm
Well this one doesn't do that and doesn't work well on my sockets . I have to use a UK to EU(Type G to F ??? blob:https://www.dropbox.com/1b062708-409e-4ccc-b9c3-485785168d62 )  adapter to work on the plugs  :-DD It doesn't trip with DC voltages... Now its time to perform a test on a Isolated transformer , 220 VAC 6VA .

I've found the manual of the model i've purchased. it is a VoltAlert 1AC-D :

http://www.avtechtrading.info/uploads/TOOACV01%20AC%20Voltage%20Tester.pdf (http://www.avtechtrading.info/uploads/TOOACV01%20AC%20Voltage%20Tester.pdf)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2018, 11:28:02 am
joeqsmith would have a field day with this meter; starting at about 33:30 I put the non-volt ranges through a ring generator (90VAC, 20Hz, but the load probably took it down to about 40VAC) and the meter goes completely haywire.
I have not seen any other reviews for this meter.  Someone had pointed it out to me in a YT comment.  They had a 3D drawing of the meter and I could see it was similar to other low end meters I have looked at and figured why bother.   

I don't know your language but I watched your video anyway.  It's funny how the brain will put a story together just based on your voice and gestures.  There is not much to these handheld meters which also helps in following along. 

Yes, that input trace to what appears to be the ground plane looks bad.  The large fuse you show appears to be the same that was in the Meterk. The end caps will just pull off on that one.  You should find it is filled.  On the Meterk, the smaller fuse was NOT filled.  Contrary to what Fungus believes, not all ceramic fuses are filled safety fuses.   You would need to pull it apart and have a look.    It took a while before I figured out that you were using a telephone ring generator.  Google pictures to the rescue.   :-DD

In the end, I get the feeling there was not a lot of praise coming from you.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 08, 2018, 11:57:00 am
I still haven't managed to blow the fuses in that meter yet. The other day I used it to measure the current flowing through a 20,000V CO2 laser tube, but no luck. 

(18mA)

When I do I'll be sure to pull them apart and look inside.  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 08, 2018, 02:11:26 pm
The fuses are filled with air or sand and of course the fillament :p  :-DD

Just kidding.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 08, 2018, 08:47:07 pm
Well at least we know with a lot of volts and amps they will break :


https://www.youtube.com/watch?v=0-HYPdh744M (https://www.youtube.com/watch?v=0-HYPdh744M)


From photoninduction :P Big fat capacitor

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2018, 10:28:54 pm
Some details about the testing but not much...

https://youtu.be/9kcHAnGOhxo?t=30
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2018, 10:42:27 pm
A little higher energy test setups than what I use to benchmark the meters.   Here they talk about the filler and it being packed.   I think there is a bit more to it than what you see posted here.  Just add some sand, its free sort of posts....

https://youtu.be/Uj0oHUSSW_8?t=13
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 08, 2018, 10:50:09 pm
joeqsmith would have a field day with this meter; starting at about 33:30 I put the non-volt ranges through a ring generator (90VAC, 20Hz, but the load probably took it down to about 40VAC) and the meter goes completely haywire.
I have not seen any other reviews for this meter.  Someone had pointed it out to me in a YT comment.  They had a 3D drawing of the meter and I could see it was similar to other low end meters I have looked at and figured why bother.   

I don't know your language but I watched your video anyway.  It's funny how the brain will put a story together just based on your voice and gestures.  There is not much to these handheld meters which also helps in following along. 

Yes, that input trace to what appears to be the ground plane looks bad.  The large fuse you show appears to be the same that was in the Meterk. The end caps will just pull off on that one.  You should find it is filled.  On the Meterk, the smaller fuse was NOT filled.  Contrary to what Fungus believes, not all ceramic fuses are filled safety fuses.   You would need to pull it apart and have a look.    It took a while before I figured out that you were using a telephone ring generator.  Google pictures to the rescue.   :-DD

In the end, I get the feeling there was not a lot of praise coming from you.
Thank you; that is truly an honor to have you watching something from me - I learned so many nuggets from your videos. I would love to have the energy and time to create decent captions, but unfortunately this is a full time job on itself. I could do dubbing as well, but unfortunately this means almost re-doing the video. Oh, well...

Regarding the details, you are right that I had a bit of trouble with the input traces and their lack of creepage, but I was very impressed by the quality of the PCB material - the copper is quite thick for your regular cheapie meter, and the amount of via stitching is impressive. I had my suspicions about the fuse, their lacking specs (less than nominal 1kV) and their ludicrous 100kA claim (although it may be mildly possible at the rated 380V).

I also commented on the very lonely PTC to protect the inputs, which is located after the switch (something you mention in your videos and I learned to pay attention), as well as the vias on the middle of the wiper contacts, which may wear out after years of very intense use.

I have been using the ring generator (a BlackMagic module scavenged from an ancient Gandalf ISDN modem) for quite some time when testing the AC range of my meters. However, it was the first time I put it to try to break a meter - it has low enough energy to not blow it on my face, but high enough to show my audience the reason why protection is important. I make a statement on a caption of what would happen if a user accidentally connects the probes in an outlet, considering it was behaving so badly with such low energy.

Overall I think you can put this meter to very good use in electronics if you are on a shoestring - that is the case of most of the audience, given that import taxes in Brazil are ludicrous and an A-brand can easily go to 2~3x the price. With that scenario, folks tend to be a lot more forgiving of a meter's issues and may take some dangerous risks. But you are right that I wasn't much cheerful due to all the issues shown.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 09, 2018, 12:17:55 am
Funny, I wasn't thinking you were trying to damage the meter with the phone ring generator.   You could get a piezo grill starter if you wanted to try and zap one.  The problem I see is that they are not consistent from unit to unit.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 09, 2018, 12:45:59 am
Funny, I wasn't thinking you were trying to damage the meter with the phone ring generator.   You could get a piezo grill starter if you wanted to try and zap one.  The problem I see is that they are not consistent from unit to unit.
Well, a manner of speaking. I wasn't necessarily trying to damage the meter but instead putting to test if their claimed 550V of overvoltage protection was actually true.

I think a distinction between the grill starter and the ring generator is that the latter is closer to the scenario where someone has the wrong range - it takes several seconds to realize the meter is under duress of a continuous voltage. The grill starter and all the tests you do are similar to a true transient hitting the equipment completely at random.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 09, 2018, 12:23:24 pm
Some details about the testing but not much...

https://youtu.be/9kcHAnGOhxo?t=30

Nice one, the switch is activated mechanically by remote wire to blow thats fuses. Not much details on what load they were indeed...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 09, 2018, 12:25:20 pm
A little higher energy test setups than what I use to benchmark the meters.   Here they talk about the filler and it being packed.   I think there is a bit more to it than what you see posted here.  Just add some sand, its free sort of posts....

https://youtu.be/Uj0oHUSSW_8?t=13

Yes but they talk about "specific" quartz sand and also special care about compression.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 09, 2018, 12:30:55 pm
Funny, I wasn't thinking you were trying to damage the meter with the phone ring generator.   You could get a piezo grill starter if you wanted to try and zap one.  The problem I see is that they are not consistent from unit to unit.
Well, a manner of speaking. I wasn't necessarily trying to damage the meter but instead putting to test if their claimed 550V of overvoltage protection was actually true.

I think a distinction between the grill starter and the ring generator is that the latter is closer to the scenario where someone has the wrong range - it takes several seconds to realize the meter is under duress of a continuous voltage. The grill starter and all the tests you do are similar to a true transient hitting the equipment completely at random.

The lots of residue of flux and poorly soldered jacks would be bad on a 230V diy circuit such as a triac driver, when for example you do some friction on the electric plugs and causes arcs. It ill buzz a little bit, but also trip the meters as beeping and OL. Thats when it is needed to cut power ASAP and redo connections. Not sure if would arc in the flux residue or the bad soldering.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 09, 2018, 03:50:48 pm
I have seen much worse solder flux residue around jacks and HV resistors that did not arc when the regular 1kV is applied. A triac dimmer could see some problems if the temperatures become very high- although to melt flux I suspect the dimmer would be toasted a long time before.

When I give my verdict of a cheap meter I take into consideration also what I have seen before from the bottom of the barrel: loose metal (springs, solder blobs, wiper contacts) and other "creative work" on solder joints and components. This meter was well put together for the price.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 09, 2018, 04:29:10 pm
Some of the later low cost meters I have looked at from ANENG, MeterK are actually assembled well compared with my much higher cost Extech that I use.   The new revision of the Harbor Freight meters still don't have very good construction.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 10, 2018, 12:54:43 am
I've openend the broken anengish meter and had also some flux residue on the front side:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1924219/#msg1924219 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1924219/#msg1924219)

Yes it is very good built quality and lots of features if considering the price .

Is it possible to create some sort of capacitive controlled, load to test the breakdown current of the HRC fuses ? That would require to test under the maximum voltage has well... lots of energy envolved.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 10, 2018, 01:49:03 am
I've openend the broken anengish meter and had also some flux residue on the front side:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1924219/#msg1924219 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1924219/#msg1924219)

Yes it is very good built quality and lots of features if considering the price .

Is it possible to create some sort of capacitive controlled, load to test the breakdown current of the HRC fuses ? That would require to test under the maximum voltage has well... lots of energy envolved.

We can see the size of some of that test equipment in those videos.  I wonder if we found the standards they mention, if they describe in more detail what sort of waveforms they use, how the equipment is calibrated and such.   I wonder just how many Joules we are talking about.   

Nothing anyone would ever attempt at home, we except ProtonicInduction.   I think it was in the very last video he made he shows the large capacitor bank that he put together.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 10, 2018, 09:52:39 am
Nothing anyone would ever attempt at home, we except ProtonicInduction.   I think it was in the very last video he made he shows the large capacitor bank that he put together.   

Did he make no more videos after that? Has he vanished from the internet?
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on December 10, 2018, 10:14:14 am
He said something bad (and correct) about the mess that immigration services make in the UK, then removed the video and disappeared. He's probably banged up in some dungeon somewhere.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 10, 2018, 10:17:19 am
He said something bad (and correct) about the mess that immigration services make in the UK, then removed the video and disappeared. He's probably banged up in some dungeon somewhere.

Not in some dungeon...

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2003621/#msg2003621 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2003621/#msg2003621)

Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on December 10, 2018, 10:38:00 am
Ahha! Well spotted whoever found that.
Title: Re: Handheld meter electrical robustness testing.
Post by: Hydrawerk on December 10, 2018, 10:01:41 pm
joeqsmith
Please what was the verdict on your new Fluke 87V ? If I understand right it passed the high voltage test according to CAT rating but there was some wear on the rotary switch?
Is Fluke 87V worth buying when compared to Hioki and Keysight??
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on December 10, 2018, 10:30:59 pm
Is Fluke 87V worth buying when compared to Hioki and Keysight??

"Worth buying" is a very subjective opinion. The facts are that the 87V is a somewhat old design and the price is rather high for an item where the design costs have (presumably) been amortized many times over. That makes the value proposition (the "worth") a tricky decision.

If you are an industrial or commercial electrician who needs an industry standard tool, then maybe it is worth it.

If you work with electronics on the bench in an R&D or hobby context then probably there are much better choices than the 87V for your needs.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 10, 2018, 11:07:07 pm
For that, check latest discussion at:
https://www.eevblog.com/forum/testgear/choosing-between-fluke-179177-vs-keysight-u1242c-vs-fluke-87v/ (https://www.eevblog.com/forum/testgear/choosing-between-fluke-179177-vs-keysight-u1242c-vs-fluke-87v/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 11, 2018, 12:17:32 am
joeqsmith
Please what was the verdict on your new Fluke 87V ? If I understand right it passed the high voltage test according to CAT rating but there was some wear on the rotary switch?
Is Fluke 87V worth buying when compared to Hioki and Keysight??

Let's ignore the CAT rating part of your question as I really have no way of evaluating any meter's safety rating.   I ran a few of these.  The new one (SN 490xxxxx) survived all the way up to 10KV, 2 ohm source, 50us FWHH.  It was finally damaged at 12KV.   That's a pretty big hit and only a few meters have survived to this level.   At one time I ran a very old one (SN 105xxxxx) which was damaged at 1.5KV.    I've ran a fair number of Flukes and this one stuck out like a sore thumb.  I had rebuilt it and decided to have a closer look into why it failed at such a low voltage to the extent of making a model of the front end.  I really could not come up with any reason why it was damaged.  In the end I reran this meter and using my smaller transient generator, the meter survived to it's maximum setting which is just under 6KV with a 100us FWHH.  IMO, you make it to this level, you have a pretty robust meter.   

As for the switch, yes I cycle tested one.   50,000 full cycles, from one dead stop, to the other and back being one cycle.  The same as I have every other meter I have looked at.  Non stop.  No cleaning the contacts during the test.   The meter was grinding really bad and when the test was finished, the pads appear to have chatter marks (if you are a machinist).  This seems to be the source of the grinding.   

The Fluke 17B+ is still king of the cycle testing.  Both of these meters were reassembled after inspection without any cleaning.  At some point I plan to do something with them.  Maybe use them as a banchmark for other meters. 

I only ran that one Keysight and HIOKI meter.   The Keysight was a big let down.  They appeared to have used a glass filled plastic for the detent spring for the switch.  All four prongs cracked early on in the cycle testing.   The meter, even with it's GDTs did not prove to be very robust.  I do like my old HP bench meters but lets just say I am not itching to get another Keysight meter.   Keep in mind, a different model could do very well.  I have no idea. 

HIOKI, well  let's just say I have some bias there.  I use some HIOKI equipment for work.  If I am working in CAT III, that is what I am using.  That meter is a bit on the pricey side but has more than paid for itself.     For my tests, I bought something lower end.  More like Fluke's 115. 
It didn't let me down.  At 10KV the meter started to arc around the plastic insert but had no electrical damage.  I added a bit of plastic to extend it a bit further through the slot and tool the meter to 14KV!  It was rock solid.   

Again to be clear because you mention the CAT ratings, these are NOT the waveforms used for the IEC surge test.  Those tests are conducted using a combo generator.  In other words they have two waveforms, current and voltage.   Because my goal has never been to look at safety, I was not concerned with the current waveform.  I used the voltage waveform as the base for my test sort of but limit the energy to about 20 Joules.  Hardly enough to do any damage at all.  I just want enough to cause a meter to fail but not come apart.  So you will NEVER see the explosions with my setup like you could with an actual arc flash event.   

I don't make recommendations.  Everyone will have different needs for their tools.  I can tell you that personally for my hobby use, of all the Flukes I have, I use that 97 scope meter and the 189s from time to time.  My handheld meter of choice is still the Brymen BM869s.  My second choice is the Fluke 189.  It's old but I like it.   If UNI-T would get off their butts and make a better version of the UT181A, I would be all over it.  It's a nice replica of the Fluke 289 with some improvements.   Then there is that Gossen Ultra.  So much potential destroyed by marketing and sales.  It does seem to have a lot of hype.  I use both of these meters from time to time but they have both been modified to better fit my needs.       

If you look in my trailer, you would still find my beat up old Mastech meter on it's last legs.  I plan to replace it with the BM319s.       
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 16, 2018, 10:43:24 pm
Dead camera batteries have prolonged the life of another meter. 

The choice of meters should provide a clue.  Looks about the size of a popular meter..... 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 17, 2018, 12:31:57 am
The disposal of the meters and the types reminds this video:

https://www.youtube.com/watch?v=_u_34E5ZUOI (https://www.youtube.com/watch?v=_u_34E5ZUOI)
 
Maybe the 121GW but all meters in the pack have bargraph so it could be the hioki DT4252 has well.  :-DMM

[Edit] Could be a Surpeer AV4???
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 17, 2018, 01:57:23 am
Those are some fairly low end meters in that video except for one.  Some may say that in the real world, things like this don't matter.  I have a much different opinion about such things. 
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on December 17, 2018, 02:49:16 am
Dead camera batteries have prolonged the life of another meter. 

The choice of meters should provide a clue.  Looks about the size of a popular meter.....
121GW with the latest mods ?  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 17, 2018, 10:49:50 am
Those are some fairly low end meters in that video except for one.  Some may say that in the real world, things like this don't matter.  I have a much different opinion about such things.

Well it depends the field were it is going to be applied , at home , industrial harsh enviroment or heavy use on electrical instalations.

So the video about magnetic sensibility doesn't quite well matches the photo.. but it was a tryout video for a clue of course :P So that could leave to the 121GW as the meter in the bag , being the one that is not low end and it's not the cem / extech .


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 17, 2018, 01:25:16 pm
For me, having a meter this sensitive to a magnetic field would be a problem.  With my hobby it would be less of a problem.  I would more apt to spend some time understanding the problem and trying to come up with a fix.  At work my solution would be "lesson learned", "never again" and chuck it.  In the field I would never risk anything other than name brand equipment.  The equipment has to work without question.  When I brought in that first HIOKI for a trial, I asked the sales people if I could test it (for real).  They agreed and I ran several potentially destructive tests on it.  Some with their sales present.   Not the little waveforms I play with at home to benchmark the handhelds.   We bought two of them as a result.  The one is now over 10 years old. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on December 17, 2018, 02:06:10 pm
magnetic resistance is important IMO,
you cant trust a meter if you cant use it near a transformer or other large Q coil.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 17, 2018, 02:25:47 pm
Sensitive multimeter than it could be the 121GW the one on the bag, Hioki then may be out of the bag, due to the testimonial of survival. It's sad that the meters  Gossen Metrawatt Metrahit and 121GW showed that sensibility at first try and  had the potential to be great meters. Mayble a revision / recall would do the job.

 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 17, 2018, 06:47:14 pm
Dead camera batteries have prolonged the life of another meter. 
This tells me it survived the spark and (perhaps) the "lower" (2kV, 4kV) voltages. Better than a throwaway.

The choice of meters should provide a clue.  Looks about the size of a popular meter.....
This gives a lot of room for speculation, given you are not saying anything about the actual popularity of the meter (only about its size) - it could be a 121GW, a Surpeer AV4 or even a more obscure brand such as... The one we talked about before.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 18, 2018, 03:54:24 am
The meter is blue if that helps and it is still in fully working order.  It's also far from the worse meter I have ever looked at.   That should narrow things down a bit.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 18, 2018, 12:16:43 pm
Ahn... I see someone has been taking advantage of a fire sale from a certain popular internet sensation... 

Well, that or a Tektronix TX3... Oh, wait... that wouldn't fit on the photo...  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 18, 2018, 01:02:24 pm
Well, it does support BLE is that helps narrow the search.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 18, 2018, 11:42:43 pm
Let me guess it is a brand new OWON B35 and the other meters was just for diversion  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on December 19, 2018, 02:01:43 am
Could it maybe be a Metrix mtx3293bt?! I've been hoping you might run something from them for awhile now, but they're certainly not inexpensive meters. Chauvin Arnoux meters don't seem very common in the states. Can't remember if you've torture tested any weird meters that lack a rotary switch now that I think about it.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 19, 2018, 02:55:19 am
I can think of a few with Bluetooth (peaktech 3440, the Metrix above, Owon OW18B), but specifically BLE and blue is somewhat limiting to the Owon proposed by Malagas and the BT33+ (https://www.banggood.com/OWON-BT33-Digital-Bluetooth-True-RMS-Multimeter-AC-DC-Voltage-Current-Tester-p-1198236.html?cur_warehouse=CN).

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2018, 01:55:00 am
The blue meter w/ BLE

https://youtu.be/nXjVc4Rmg7Y
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 20, 2018, 02:11:03 am
So many close calls... Congratulations on the new meter!

I'll watch it later.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 20, 2018, 10:22:49 am
Did I claim that "all" ceramic fuses are filled or only that I believed the ones in that $14 LIDL meter would be filled?

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 20, 2018, 10:25:37 am
Looking at the quality of the printing on this fuse, I doubt it's really by SIBA:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=600991;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 20, 2018, 11:45:35 am
I'll watch the video later. The meter was also available on the OWN website :P

http://www.owon.com.hk/products_owon_4_1|2_digital_multimeter_with_bluetooth (http://www.owon.com.hk/products_owon_4_1|2_digital_multimeter_with_bluetooth)

Why there isn't a CAT rating on their advertisement?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2018, 01:38:29 pm
Did I claim that "all" ceramic fuses are filled or only that I believed the ones in that $14 LIDL meter would be filled?

"High" is a relative term but I thought all ceramic fuses were "HRC" type.

(otherwise they'd use glass, which is cheaper)

Save you the trouble of using the advanced search:
https://www.eevblog.com/forum/blog/eevblog-1095-1096-aneng-q1-multimeter/msg1609810/#msg1609810 (https://www.eevblog.com/forum/blog/eevblog-1095-1096-aneng-q1-multimeter/msg1609810/#msg1609810)

Looking at the quality of the printing on this fuse, I doubt it's really by SIBA:

Most of the ones that I show were from meters that were recycled.   I'm not sure what meter that SIBA fuse came in.    When I made that video on what I suspected was a counterfeit SIBA I contacted them to see if they could provide any insight.  They never responded.   I suspect I would get the same response if I tried to contact them again.     Just like Keysight. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 23, 2018, 12:18:23 am
Here are some new cheapo models that has some extra features...

BSIDE True RMS Digital Clamp Meters 1mA Resolution DC/AC Current Voltage Tester

 https://ebay.us/jxLsWt

C902 Digital Clamp Meter AC/DC Voltage Multimeter Ohm Volt Amp Tester ( fluke ripoff?)

https://ebay.us/LZeo8C

The blast shield is really effective in protecting from these abominations.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 23, 2018, 01:01:02 am
Here is the guts of the uni-t 204A clamp meter... it is so tight and the input voltage runs a wire to the board. At least is crimped and soldered...Some M.O.V. and a PTC what looks like.. and a lot of melf resistors. Damn so many trim pots... 

The clamp meters looks they have a miniaturized selector switch  and done poorly in low end models as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 23, 2018, 01:27:33 am
That does look pretty tight. 

You don't always get what you pay for with these junk meters.   That TPI/Summit 194II is a good example.  At least with the UNI-T UT181A, I can see they made an attempt.   So more money does not guarantee a more robust meter.   I have lost a switch on a BK, Mastech and UNI-T within a few years of use.  They are just not made to last very long with moderate use but then again, I doubt people (including myself) ever buy these off brands thinking they are going to have a long life.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 31, 2018, 11:01:11 pm
I may add the table to the spreadsheet.   Basically, all the assumptions on the battery life are listed, if someone wanted to replicate the tests.  Battery numbers of from Wiki.  They are all alkaline.   I have not taken the time to look up any datasheets. 

The nominal is with the meter in ACV, no other options.  Backlight is measure in ACV w the backlight active and set to it's highest brightness.

Some meters like the Gossen and the CEM have built-in radios.  The Amprobe has a flashlight.  I run through all the modes, except with the backlight off to measure the max function current.   

Meters are sorted by their nominal battery life.  In my case with the Gossen for example, I never turn off the radio so the 42 hours is closer to what I would expect. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 01, 2019, 11:58:55 am
Jesus The brymen BM869s drains almost the 9V battery to nothing. They really do last, if assuming they are from the same brand.

An odd example the uni-t 204A clamp meter has a cut-off near 5.8V on nimh cell, but on alkaline is 7.2V for 9V battery. The clamp drains a lot the energy.



Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 01, 2019, 02:45:21 pm
Happy new year!

Wow... If I read it correctly,  the 101 has 800h of lifetime! That is what Keysight claims on the U1282A. Later I will try to do some measurements on it, throwing also the U1273A, the BM857 and the venerable Flukes of yore (8020A, 8060A, 8062A).
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 01, 2019, 05:50:41 pm
Happy new year as well.   

The Fluke 17B+ and latest version of the free Harbor Freight meter appear to have the longest battery life based on my Wiki battery data. 

You won't find a lot of cheap meters, because they were recycled after they could not be repaired, or in the case of the UT61E and ZT-102, they were modified to the point where I expect it would corrupt the data.  A bit tired of dealing with the 121GW prototype and left it off as a result. 

I used to get a lot of negative comments about that 17B+. Seeing it do so well in my transient tests, switch life cycle testing and now what appears to be a very long battery life,  if you can live with the features it has, it appears to be a pretty decent meter. 

There is a previous link to a thread showing some of the test jig.  The BM869s was one of the meters I used during my testing.  I mentioned a few details about the cutoff voltage.   The software is currently looking for the current draw to be less than half of the nominal.  In the case of the BM869s, a low battery alarm was set long before this. 

You can see how they behave as the voltage is ramped down.   The cutoff is not always a nice sharp edge. 

If anyone has some ideas on how they would like to see the data measured or presented, feel free to make your suggestions.

**********
In the last plot, I have added a cursor readout.  The Brymen BM869s is selected and the cursor is placed where the alarm is just ready to sound.  We can see the voltage is 5.7, much higher than the 2.8 volts shown in the table for the half nominal.  The meter is still running down at 2.8 but as I mentioned, the results are not predictable.    I think as long is it is clearly stated how the measurement is taken, it should be fine.. Then again...  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 02, 2019, 12:35:31 am
Was going to ask about including the uni-t 210e clamp meter but since it is very modified it can give different results from a non modified as mentioned

what about include on the spreadsheet the claimed battery life on manual for comparisson ?

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 02, 2019, 01:59:25 am
Was going to ask about including the uni-t 210e clamp meter but since it is very modified it can give different results from a non modified as mentioned

what about include on the spreadsheet the claimed battery life on manual for comparisson ?

I will make you a deal.  You spend the time hunting down this information and I will gladly add it.  As I mentioned, many of the meters don't have these numbers published so you will need to contact the manufactures. 

This seems to include meters by UNI-T, Amprobe (OEM UNI-T), CEM, ALLOSUN, OWON and Brymen. 

Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on January 02, 2019, 02:43:49 am
Battery life for a DMM is a "how long is a piece of string" question. The power draw depends not only on obvious factors like use of the backlight, but on less obvious factors like use of resistance, capacitance and continuity ranges (where power is expended for the test), compared to voltage measurements which are basically passive. I can see why manufacturers would decline to state an expected battery life. It is going to depend a lot on the usage profile which they have no control over.
Title: Re: Handheld meter electrical robustness testing.
Post by: xrunner on January 02, 2019, 02:53:20 am
Battery life for a DMM is a "how long is a piece of string" question ...

Yep, they won't tell you that info, but they will sometimes say "Do not leave batteries in if you do not intend to use for an extended period of time".  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 02, 2019, 03:34:08 am
Battery life for a DMM is a "how long is a piece of string" question. The power draw depends not only on obvious factors like use of the backlight, but on less obvious factors like use of resistance, capacitance and continuity ranges (where power is expended for the test), compared to voltage measurements which are basically passive. I can see why manufacturers would decline to state an expected battery life. It is going to depend a lot on the usage profile which they have no control over.
Except that Keysight advertises this for both their U1272A (https://www.keysight.com/en/pdx-2882338-pn-U1272A/handheld-digital-multimeter-4-digit-ip54?nid=-32044.1242727&cc=US&lc=eng) and U1282A (https://www.keysight.com/en/pdx-2883096-pn-U1282A/handheld-digital-multimeter-4-digit-ip67?cc=US&lc=eng).

Quote from: U1272A
300 hours of battery life and Keysight Remote Link Solution enabled (wireless data logging via Bluetooth)

Quote from: U1282A
Stay productive with 800 hours of battery life and datalogging via Bluetooth
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 02, 2019, 03:47:02 am
Fluke and HIOKI publish numbers.  I appended them to the file names. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 02, 2019, 11:42:08 pm
The brymen BM235 has also that information , measured by Dave himself on the EEvblog.

Thats a big proposition .... already regreting ... exclude the uni-t's from the list  they don't have that

 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 03, 2019, 01:28:56 am
I saw that but thought you wanted the manufactures numbers for a comparison.   

If Dave's numbers are acceptable to you and the data I am collecting is not, please explain how you would like to see them measured.

***

Note his 3.2 mA is very close to what I measure with nothing connected to the meter and looking for the worst case mode, with the backlight off.   I was using 1000mA/hr from Wiki (860–1,200 and split the differnce) for AAA Alkalines to get the 312 hrs.  Dave was using 770mA/hr.    Energizer Alkaline for example does not have any data for the 3.2mA the meter is pulling.   As suggested, it's all a bit of a swag. 

http://www.farnell.com/datasheets/1912477.pdf (http://www.farnell.com/datasheets/1912477.pdf)

If you would like to suggest other numbers be used, you could always just download the data and plug it into a spreadsheet.   Best I can offer is some sort of standard way to measure them in order to compare them.
Title: Re: Handheld meter electrical robustness testing.
Post by: Kean on January 03, 2019, 12:35:42 pm
I was using 1000mA/hr from Wiki (860–1,200 and split the differnce) for AAA Alkalines to get the 312 hrs.  Dave was using 770mA/hr.

Sorry to be pedantic, but the unit is mAh (milliampere-hour) not mA/hr.

Also I spotted mH/hr (millihenries per hour?) as the column header on your chart.  I admit that made me LOL a little...  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 03, 2019, 02:03:48 pm
 I was starting to research for the list of meters marked on the test and saw later that there was the rated capacity ob the filename. I slow down the research because of lack of manufacture info and i spoted the bm235 that had that info but unaware of the details of that test.

The tests of batt min and bat max should cover the worst / best scenarios of the meter and see it falls in between the specified by the manufacture as a reference value. For example bat min would be measuring a constant current, max brigthness  and bat min mV, no brightness . Batteries would be the same brand with available datasheet and maybe a example test between nimh and alkaline cells on the most hoging meter.

   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 03, 2019, 04:29:54 pm
Meanwile found another device that might get the attention for the ones trying to measure voltages on electric fences with meters,:

https://www.ebay.com/itm/Electric-Fence-Voltage-Tester-600V-to-7000V-Pocket-Garden-Tool-Controller-for-EU/302628255828 (https://www.ebay.com/itm/Electric-Fence-Voltage-Tester-600V-to-7000V-Pocket-Garden-Tool-Controller-for-EU/302628255828)

It uses neon lamps as indication for the voltage ( bargrapth) like the mains voltage tester, targeted for low impedance and measured between groound + fence. 

 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on January 03, 2019, 11:37:53 pm
nice, but dangerous.

it should have had the probe extending from the case,
so you anchor the earth rod, and then probe the fence while ONLY holding the case.

from those images they expect you to hang it on the fence while holding the grounding probe!!
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 04, 2019, 12:24:48 am
nice, but dangerous.

it should have had the probe extending from the case,
so you anchor the earth rod, and then probe the fence while ONLY holding the case.

from those images they expect you to hang it on the fence while holding the grounding probe!!

Well someone demonstrate the oposite way :P

https://www.youtube.com/watch?v=GL8BZjtw8Ao (https://www.youtube.com/watch?v=GL8BZjtw8Ao)

Ground somewere else and probe the fence with hand.. those neons dont bright very well...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 04, 2019, 12:34:07 am
I was using 1000mA/hr from Wiki (860–1,200 and split the differnce) for AAA Alkalines to get the 312 hrs.  Dave was using 770mA/hr.

Sorry to be pedantic, but the unit is mAh (milliampere-hour) not mA/hr.

Also I spotted mH/hr (millihenries per hour?) as the column header on your chart.  I admit that made me LOL a little...  >:D

Good catch.  I will fix them the on the next round.   The / is a bad habit of mine.   I suspect you will find it frequent throughout my posts for other units as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 07, 2019, 01:14:59 pm
Wow the flashlight must be super bright and efficient
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 07, 2019, 03:10:29 pm
Wow the flashlight must be super bright and efficient
It's actually very dim and not very efficient at all.   The key was testing the stimulus's current limit.  Many people want to show lighting an LED as part of their meter reviews.  The custom meter can push about 500mA at more than 20 volts.   More than enough to test my HV diodes and power any handheld meter I have seen to date but not enough to power my flashlight.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 07, 2019, 05:38:10 pm
Joe, I did some measurements with a few of my meters.
edit 1: I added the BM857 and the 8060A
edit 2: I added the UT136C, MAS830L and 27/FM and reordered by Nominal
edit 3: I added the PM300
edit 4: I added the Mestek DM91A and the UT139C

All current and voltage measurements were done with my Keysight 36312A (cal due Aug/2019)

ModelPack DescriptionmAhNomCurBacklightMaxFuncCutoffNominalMin
Keysight U1273A4X AAA LR03100030mAN/A34mA4.2V33.33h29.41h
Brymen BM8571X 9V 6LR615505.2mA42mA5.6mA5.8V105.8h98.20h
Fluke 8060A1X 9V 6LR615504.0mAN/A4.6mA3.9V137.5h119.6h
Sanwa PM3001X 3V CR20322351.4mAN/A2.0mA1.7V167.8h117.5h
Uni-T UT61E1X 9V 6LR615503.2mAN/A5.4mA1.6V171.9h101.9h
Surpeer AV41X 9V 6LR615502.8mA31mA5.2mA3.1V196.4h105.8h
Uni-T UT136C1X 9V 6LR615501.8mAN/A2.9mA2.3V305.6h189.7h
Keysight U1282A4X AA LR0620005.3mA38mA7.1mA3.9V377.4h281.7h
Mestek DM91A2X AAA LR031001.7mA3.7mA3.2mA2.2V588.2h270.2h
Fluke 27/FM1X 9V 6LR615500.7mAN/A1.7mA3.6V785.7h323.5h
Uni-T UT139C2X AA LR0620001.7mA10.5mA2.4mA2.1V1176h833.3h
Mastech MAS830L1X 9V 6LR615500.3mA30mA1.9mA4.4V1833h289.5h

Considerations:
- VAC used on NomCur. No other modes or settings.
- UT61E is unmodified (non-GS version).
- Cutoff voltage measured until meter is powered off. Low Batt indicator was not considered.
- AV4, 8060A, BM857 and MSP830L started drifting. This was the Cutoff voltage used.
- UT61E, UT136C, 8060A, 27/FM and PM300 do not have backlight. U1273A has OLED display.
- Battery life was obtained with mAh/current. Far from ideal, given the cutoff voltage will reduce that, but enough for comparison.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 07, 2019, 06:09:56 pm
Very nice work.   I am surprised that Keysight would make something with even lower life than the UNI-T.  Then again, who puts glass filled plastic in their detent springs. 

I had looked at the UT61E's cutoff voltage before and remember it running way down in the muck like you show.  I may run my modified 61E and see how much worse it is.   

Minor detail, in my test setup the voltage is read across the meter.  Basically I did not want my shunt to come into play. 

I am not sure how to deal with the cutoff.  Some meters' like the BM869s will run way down below the battery warning and audio alarm but it can also throw up some bad data.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 07, 2019, 06:47:14 pm
Very nice work.   I am surprised that Keysight would make something with even lower life than the UNI-T.  Then again, who puts glass filled plastic in their detent springs. 
Thanks. The U1273A is on par with the other meters if the backlight was constantly on, which is the premise of the OLED display. In my regular use I don't see it being a terrible user experience, however I am in the US where batteries are dirt cheap when compared to my country of origin.

Minor detail, in my test setup the voltage is read across the meter.  Basically I did not want my shunt to come into play. 
The E36312A has 4-wire mode, but I couldn't be bothered. I may re-run and see if there is any influence.

I am not sure how to deal with the cutoff.  Some meters' like the BM869s will run way down below the battery warning and audio alarm but it can also throw up some bad data.
I am not either. The discharge rate is very non-linear; a battery drained to the cutoff level of an UT61E is quite unrealistic for practical purposes, given the meter beeps at power up and severely drops the voltage of such discharged battery.

I have one of these cheap chinese electronic loads that I could test a fresh battery and see its discharge curve, but in the end this is not really a valid sample.

All in all, these days I am much more concerned with chemical damage than with actual battery life. I ended up with non-rechargeable Lithium AA batteries in the U1282A just because it uses so little power. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 08, 2019, 12:38:24 am
With the UNI-t, the backlight can be turned off and there are different levels of brightness.  Of course, you can't see anything.   When I have used it for data logging, the backlight will turn off.   I would have liked to see standard batteries used in it.  I still have no idea where to get a replacement and suspect I will have to retrofit it to some other pack.   I have a 0.5 ohm in my test jig for a shunt.  Figure 50mA, or 25mV drop, it was worth removing this error.   

I had saved a battery out of one of our smoke detectors that I have been running on the jig for fun.    It's dropping like a  rock while I am typing.   :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 08, 2019, 02:54:06 am
Comparing the current with my HP 34401A.   I suspect based on your numbers that this battery would still power the UT61E.   


https://youtu.be/IoCGMRi536Y
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 08, 2019, 12:12:32 pm
Hi sorry to ask again this, but do you tested with NIMH cells and had any different cut-off voltage? The uni-t 204A has different cut-off  for the NIMH batteries and i've tried another brand.

So cutoff:


Code: [Select]
 
Type Brand Cutoff (V)
-----------     -------------- -------------
9V 9F22 Duracell Ultra 7.0
8.4V 9F22 Tronic  220mAh 5.8
8.4V 9F22 fullwat  260mAh 4.7



CurrMin: 1mA
CurrMax : 10mA


I've replaced alkalines for nihm  on the BM235 and unit 139A to check cutoff voltage has well, but i believe had that on the aneng meter and the cut-off was always the same for alkaline or nimh as an example of consistency on battery cutoff for AAA or AA batteries.

EDIT:

Please sorry for posting this results but these were obtained improperly by taking off the batteries out of the load to measure instead of measure with the load. tested with 2x AA NIMH cells with chrismas lights untill they turned off, measure voltage without removing them got 1.187V / 1.169V . When taken out they went right to 1.2V and rising...   :palm: |O dooohnhh

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 08, 2019, 12:52:28 pm
Hi sorry to ask again this, but do you tested with NIMH cells and had any different cut-off voltage? The uni-t 204A has different cut-off  for the NIMH batteries and i've tried another brand.

So cutoff:


Code: [Select]
 
Type Brand Cutoff (V)
-----------     -------------- -------------
9V 9F22 Duracell Ultra 7.0
8.4V 9F22 Tronic  220mAh 5.8
8.4V 9F22 fullwat  260mAh 4.7



CurrMin: 1mA
CurrMax : 10mA


I've replaced alkalines for nihm  on the BM235 and unit 139A to check cutoff voltage has well, but i believe had that on the aneng meter and the cut-off was always the same for alkaline or nimh as an example of consistency on battery cutoff for AAA or AA batteries.


If you watched the short video and followed the other thread, you can see how I was testing them. 

How did you measure the cutoff?  Details.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 08, 2019, 02:16:59 pm
Sorry for the lack of the details.  After the unit shutdown due to lack of  "juice" when turned on, a few minutes of use, took the battery out and measured with another meters , the uni-t ut50b and the ut120c, in volts mode. Also let the batteries settle down for 10 minutes and still measured the same voltage, same meters.

This experience is a bit old so didn't follow the same guidelines, because of the issue of draining to quickly the 9V alkaline batteries in Amps with clamp meter... and opt for NIMH batteries since buying alkaline would become expensive alternative



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 08, 2019, 03:01:25 pm
Sorry for the lack of the details.  After the unit shutdown due to lack of  "juice" when turned on, a few minutes of use, took the battery out and measured with another meters , the uni-t ut50b and the ut120c, in volts mode. Also let the batteries settle down for 10 minutes and still measured the same voltage, same meters.

This experience is a bit old so didn't follow the same guidelines, because of the issue of draining to quickly the 9V alkaline batteries in Amps with clamp meter... and opt for NIMH batteries since buying alkaline would become expensive alternative

What makes you think that you can pull out the battery with no load, read it's voltage and get ANY meaningful results?   Clue, you can't.   That's pretty basic.    You will need to monitor the voltage with the meter attached and capture when it drops out (if that is your criteria).    If you are trying to characterize various batteries, you  may be better server tuning to the data sheets.   

 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 08, 2019, 03:29:34 pm
Oppsss i thought bad since the meter shuts down after low battery it becomes completly open to the battery. However the 7V cut off from the alkaline battery measured is similar with most of the 9V battery operated uni-t meters for example the uni-t 50b , using the same battery.  It is on the NIMH and this meter that cut-off is different but again not the best procedure to measure voltage with real load. 

What i'm trying to do is if this meter has an issue with alkaline batteries since it behaves weird after a long period of usage , when is awaken.  It doesn't happen with NIMH. Problem is it worth time investing since it is a cheapo meter?
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on January 08, 2019, 04:29:50 pm
The shutdown voltage should be the same for a multimeter , measurable with a variable power supply ... But different types of chemistry have different internal resistance when new and as the battery degrade . That "invisible" resistance is in series with the battery and produce voltage drop , so under load the voltages may be the same for all batteries at shutdown , but when pulled out different .

The internal resistance is temperature dependent , so in winter a "dead" multimeter can be revived temporarly if you heat up the battery .
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 08, 2019, 05:42:48 pm
Sorry again for pulled down the battery as soon as the meter powered off on its own on low voltage till i couldn't turn on again. Temperature is around 16ºC to 20ºC, humidity up to 70% .

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 08, 2019, 06:13:51 pm
Oppsss i thought bad since the meter shuts down after low battery it becomes completly open to the battery. However the 7V cut off from the alkaline battery measured is similar with most of the 9V battery operated uni-t meters for example the uni-t 50b , using the same battery.  It is on the NIMH and this meter that cut-off is different but again not the best procedure to measure voltage with real load. 

What i'm trying to do is if this meter has an issue with alkaline batteries since it behaves weird after a long period of usage , when is awaken.  It doesn't happen with NIMH. Problem is it worth time investing since it is a cheapo meter?

I assume you own all of them that use 9V batteries and tested them to make a statement like that.   If you watched that short video, you would have seen how low my UT61E ran.  rsjsouza also tested their UT61E and posted the results.  I also posted data for the UT90.   

But again, you keep using the term cutoff and I am not sure of you are talking about an unloaded battery measurement.  So if this is what you are referring to, again its not a useful measurement when you are talking about cutoff.   

Again, from the video and last picture I posted.  I have a 470 ohm resister across the battery and am measuring the current and voltage.  After several hours, I put a 100 ohm in parallel with the 470.  The current jumps up and the voltage eventually reaches a point where it drops off fairly sharp.   I then remove the 100 ohm.   The 470 is still attached.  Note how the voltage recovers from less than 2 volts to roughly 7.   This happens in a very short time. 

It seems Dave make a few videos on it.  There are also some decent physics/chemistry channels that go deeper into the subject of batteries. 

Here you go...
https://youtu.be/dnXiLBabSTU
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 08, 2019, 10:03:19 pm
Hi there

Thanks for the information on the video.

Tested some and  uni-t's before buying one... they would turn off by lack of juice in the battery and the its voltage would be around 7V ( ut58... ut50... ut200 series.. ut33 ) with alkaline battery duracell ultra... The usual was taking off the battery and put another one... and measure the old one . The thing was when i purchased the ut204A i was testing some current measuements with sotck battery and it depleted the battery to nothing in 3 hours... it wouldn't turn on where the uni-t 50b was for 3 weeks  with the same battery .. and let it run till it drained... measured 7V.

So i decided to buy an duracell for the clamp and it didn't last long enought at least when using the clamp for measuring current, same 7V measurement. goes to ut50b lasts 3 weeks.. then decided to try some nimh batteries and they pretty last longer than the alkaline batteries, different voltage when meter shut down due to lack of juice... This clamp meter also has some "features" like it doesn't sleep always after the 15 minutes.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 08, 2019, 10:17:17 pm
Hi there

Thanks for the information on the video.

Tested some and  uni-t's before buying one... they would turn off by lack of juice in the battery and the its voltage would be around 7V ( ut58... ut50... ut200 series.. ut33 ) with alkaline battery duracell ultra... The usual was taking off the battery and put another one... and measure the old one . The thing was when i purchased the ut204A i was testing some current measuements with sotck battery and it depleted the battery to nothing in 3 hours... it wouldn't turn on where the uni-t 50b was for 3 weeks  with the same battery .. and let it run till it drained... measured 7V.

So i decided to buy an duracell for the clamp and it didn't last long enought at least when using the clamp for measuring current, same 7V measurement. goes to ut50b lasts 3 weeks.. then decided to try some nimh batteries and they pretty last longer than the alkaline batteries, different voltage when meter shut down due to lack of juice... This clamp meter also has some "features" like it doesn't sleep always after the 15 minutes.

I doubt there are many meters out that that use a 9V battery that a cutoff voltage of 7 or higher.  Again, how did you measure them?  Show your test setup and explain the details. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 09, 2019, 12:55:18 am
Sorry again for pulled down the battery as soon as the meter powered off on its own on low voltage till i couldn't turn on again. Temperature is around 16ºC to 20ºC, humidity up to 70% .



This way... meter powers down, open the case, take out the battery and measure voltage with another meter...Should i measure when it is still on the meter even if is supposelly powered off? I can re-run this with the 204A because it can be turned to always on...and draws 1mA in Vac mode.
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on January 09, 2019, 05:28:34 am
This way... meter powers down, open the case, take out the battery and measure voltage with another meter...Should i measure when it is still on the meter even if is supposelly powered off? I can re-run this with the 204A because it can be turned to always on...and draws 1mA in Vac mode.

Broadly speaking, you need to know that NiMH fully drained cells "rebound" when you take the load off them. For example, a completely drained NiMH cell may have an open circuit voltage of ~1.2 V. You can put a small load on it and the voltage will drop down to 0.5 V or lower. Take the load off the cell and the voltage will rapidly rise up towards 1.2 V again. The best way to see this happening is to have the cell attached to the voltmeter when you do this experiment.

Alkaline cells don't behave the same way. They have a very small rebound or recovery, but it is much less pronounced.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 09, 2019, 12:26:52 pm
Hi.

What about leaving the ut2104A in always on mode and re-check again the voltage on the battery without remove it (it has a 8.4V 220mAh nimh currently)  Then with the same procedure using a fresh duracell ultra. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on January 09, 2019, 01:07:02 pm
you should reallly be running a pair of wires from the battery in the meter to test it's output while it's in circuit and the meter is on.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 09, 2019, 03:00:42 pm
Just a note: I added the BM857 and the 8060A to the table at my previous post:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

(Uni-T UT136C, Mastech MAS830L and Fluke 27/FM brown coming next)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 10, 2019, 09:29:45 am
Hi

First of all want to apologize for the big mistake on the procedure taken to measure batteries. So n00bian from my part :(


Willing to do another test to check the cut-off voltage of the uni-t 9V using proper techniques to see if it is unpar with the uni-t meters that you have and check if any thing weird on 204A is going on between batteries or might doing something wrong.

Edit

Don't have yet a adjustable power  supply so going to relly on batteries...
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 11, 2019, 02:55:14 pm
Yet another (most probably final) edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Added the UT136C, 27/FM and MAS830L

The verdict is that you can't beat the venerable ICL7106 in power consumption.  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 12, 2019, 12:40:48 pm
This way... meter powers down, open the case, take out the battery and measure voltage with another meter...Should i measure when it is still on the meter even if is supposelly powered off? I can re-run this with the 204A because it can be turned to always on...and draws 1mA in Vac mode.

Broadly speaking, you need to know that NiMH fully drained cells "rebound" when you take the load off them. For example, a completely drained NiMH cell may have an open circuit voltage of ~1.2 V. You can put a small load on it and the voltage will drop down to 0.5 V or lower. Take the load off the cell and the voltage will rapidly rise up towards 1.2 V again. The best way to see this happening is to have the cell attached to the voltmeter when you do this experiment.

Thanks again and i've yet tested with another battery operated device, which gave similar result ( less voltage drop) as you mentioned:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2102320/#msg2102320 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2102320/#msg2102320)



Alkaline cells don't behave the same way. They have a very small rebound or recovery, but it is much less pronounced.

Just a reminder:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2102320/#msg2102320 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2102320/#msg2102320)

...tested with 2x AA NIMH cells with chrismas lights untill they turned off, measure voltage without removing them got 1.187V / 1.169V . When taken out they went right to 1.2V and rising...   :palm: |O dooohnhh
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 18, 2019, 10:49:54 am
Quote
I assume you own all of them that use 9V batteries and tested them to make a statement like that.   If you watched that short video, you would have seen how low my UT61E ran.  rsjsouza also tested their UT61E and posted the results.  I also posted data for the UT90.   

Well that is in the description of the product sheet or specifications of the uni-t. So for example on uni-t 61E < = 7.5 V, the 7.5V would be  a worst case scenario?

Product Specification for uni-t 61E as an example:

http://www.uni-trend.com/productsdetail_1971_1105_1105.html (http://www.uni-trend.com/productsdetail_1971_1105_1105.html)

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 25, 2019, 03:23:30 pm
I added the Sanwa PM300 to the list at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on January 25, 2019, 03:31:41 pm
All my multimeter reviews (more than 80) contains current measurement for the meters and estimated runtime until they report empty battery. The estimated runtime is based on discharge curves at different currents.
Title: Re: Handheld meter electrical robustness testing.
Post by: bc888 on January 25, 2019, 06:39:38 pm

Fluke 27/FM for the win. Thanks RSJ for the list. Interesting that a 20+ year old meter is able to lead the pack.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on January 30, 2019, 10:09:30 pm
Hi.

I've catch the uni-t 204A clamp meter powered off and read the voltage of the NIMH battery inside the meter... 2.25V.... It must be draining the battery even shutted off probably...

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 31, 2019, 04:03:35 pm
Malagas, depending on the NiMH battery it may have a pretty high self discharge. Otherwise, I would inspect the quiescent current of your clamp - it shouldn't be difficult with a fresh charge and the multimeter you have in uA/mA mode.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 01, 2019, 04:08:57 pm
Thanks for the advice rsjsouza.


Plan to do a setup to measure also the current consumption in all modes to check what does get more energy from the battery using aligator clips to a multimeter in mA / uA . Also check if the current setups doesn't add up to the measure, eg bad aligator clips, bad leads. 

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 01, 2019, 04:40:51 pm
That is cool, Malagas. This is similar to the data I got from the meters I tested and shown in the attached photograph.

I plan to do a test on the quiescent current on standby, but that takes quite a long time waiting for the meters to power off automatically.

 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 04, 2019, 01:19:36 am
Would you pay $1522 for a free Harbor Freight meter?  My first digital VOM gets an overhaul.

https://youtu.be/ObKomuLLqU8
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 04, 2019, 10:11:51 pm
Hi here is my first tryout to measure current in a DMM in order to check its power drain using a almost fresh NIMH cell.. a newbie one...

Conditions....:

. DMM: Uni-t 204A clamp meter.
- Cell: 9V NIMH 220mAh
- Leads:  Using old aligator leads plugged  to terminais ( plan to user newer ones or dummy cell)
- Current Measurement: Multimeter Unit-50b in 20 mA scale in series with battery + standard test leads +  old aligator clips 
- Voltage Measurement ( Battery and DMMterminais) : Uni-t 120C

Measurements
- Check attachments .. in portuguese... sorry :P
- Battery Voltage measurement on battery and contacts was taken on the 40A DC


Further tests involves switching aligators clips,test leads, dummy cells. Measurement multimeters for better accuracy on the results. 

If there is anything missing which is.. quote ::P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 16, 2019, 09:25:14 pm
Starting to work on a new video but the German's are getting me down.  But if you like seeing old meters, stay tuned..
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 16, 2019, 11:15:32 pm
Starting to work on a new video but the German's are getting me down.  But if you like seeing old meters, stay tuned..
Oh, no! What did Gossen do this time?!? Did they set radiowave or magnetic weapons around your house to make all meters go wild?
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 16, 2019, 11:40:33 pm
Hope it's not Benning MN12 and software for windows is not working properly ....

https://www.benning.de/products-en/testing-measuring-and-safety-equipment/digital-multimeter/benning-mm-12.html (https://www.benning.de/products-en/testing-measuring-and-safety-equipment/digital-multimeter/benning-mm-12.html)

Looks nice with BLE , 40000 counts , AC+DC but on the other hand more expensive ...
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on February 17, 2019, 01:03:35 am
Starting to work on a new video but the German's are getting me down.  But if you like seeing old meters, stay tuned..

 /me is staying tuned. :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 17, 2019, 03:45:34 am
Made some progress today and saw something that I have never seen before, even with all the low end meters I have looked at.   Like many of my videos, I got a little sidetracked as well. 

Testing continues on the pocket meter that True claims they had damaged some high number of.   I don't think they ever did post again after making that first video.  Someone also asked me about running an experiment which I have decided to take on for fun.  Bouncing between the three videos as I have time.   Combined with work and other interests, I haven't been spending much time with the meters.   So be patient and perhaps in a couple of weeks you can see a brand I havn't yet looked at. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on February 18, 2019, 01:34:08 am
a real one - looks similar
(https://static.rapidonline.com/catalogueimages/product/s26-5864p01wl.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 18, 2019, 01:49:36 am
Notice the complex markings on this one.  Real or counterfeit?  We need our fuse expert Fungus to weigh in.   

I've written SIBA before about possible counterfeit fuses and they are pretty much like dealing with Gossen or a vacuum, your pick.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 18, 2019, 09:17:41 am
a real one - looks similar
(https://static.rapidonline.com/catalogueimages/product/s26-5864p01wl.jpg)

Quality of the printed letters is much better on that one.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 18, 2019, 01:03:05 pm
No comment on the third one I posted?

I am willing to take these apart and take any measurements you would care to see if you have original SIBAs that we could compare them with.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 18, 2019, 01:18:05 pm
No comment on the third one I posted?

I'm not sure about that one. On the one hand I don't see why SIBA would have two types of markings but on the other I know that when you make a comment like that it's a trap.

There's a distinct lack of pictures of fuses on SIBA's web site to compare anything with.  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on February 18, 2019, 02:39:52 pm
i dont think breaking them will tell you much, even if they are fake they can still be sand-filled.

i know there was a vid by "voltlog" testing meter fuses from another company that used test currents and timed the speed it tripped.
https://www.youtube.com/watch?v=evKKE1rsGVQ (https://www.youtube.com/watch?v=evKKE1rsGVQ)
and
https://www.youtube.com/watch?v=mmxGX0K8JII (https://www.youtube.com/watch?v=mmxGX0K8JII)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 18, 2019, 02:43:51 pm
i know there was a vid by "voltlog" testing meter fuses from another company that used test currents and timed the speed it tripped.

There have been some here, too:

https://www.youtube.com/watch?v=EWu8wMspROQ (https://www.youtube.com/watch?v=EWu8wMspROQ)
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 18, 2019, 02:45:01 pm
It appears it came with the the Keysight meter.

What do you mean by "appears"? Did you personally unbox a new/sealed Keysight meter and remove that fuse from it?

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 18, 2019, 03:08:37 pm
It appears it came with the the Keysight meter.

What do you mean by "appears"? Did you personally unbox a new/sealed Keysight meter and remove that fuse from it?
I bought the Keysight meter from Keysight, brand new.  Yes I unboxed it and proceeded to test it to failure.  Very few meters I have looked at came with SIBA branded fuses.  Most that did, used the small body style.   The Keysight meter I bought did have a 10A large body and I had pulled the fuses when I scrapped the meter.  The pulled fuses get tossed into a bag.  There is only one 10A SIBA fuse in the bag.   But, I've ran many meters over the last couple of years and it's possible there was some other meter that came with SIBA branded fuses that I scrapped.   So I use the word appears because there is a chance that it came from something else.  I'm not sure what I would have done with the fuse from the Keysight though.   

i dont think breaking them will tell you much, even if they are fake they can still be sand-filled.

i know there was a vid by "voltlog" testing meter fuses from another company that used test currents and timed the speed it tripped.
If you take the time to watch those videos you linked and read the comments, you will find he based those tests off of mine.  He had some problems with the first setup and you will see where I posted some details to try and help him sort it out.   

Again, if anyone has a known SIBA 10A, and would like to do some sort of comparison, feel free to ask.  I doubt we would get any support from SIBA on this matter.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 18, 2019, 03:31:32 pm
No comment on the third one I posted?

I'm not sure about that one. On the one hand I don't see why SIBA would have two types of markings but on the other I know that when you make a comment like that it's a trap.

There's a distinct lack of pictures of fuses on SIBA's web site to compare anything with.  :-//

:-DD :-DD   

I really don't have a lot of information on counterfeit fuses.  I am not aware of a SIBA distributor here so I would need to lean on people who have access to genuine components to compare them with.   I don't have any data on SIBAs printing process.  It's possible it could be a metric we could use to determine if they are counterfeit but we would need an SIBA expert to help out with that.

Pulling them apart may provide some indication but then again, it's possible they have multiple factories and may have changed the design over the years.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 18, 2019, 05:02:47 pm
Here are two HRC 400mA  fuses suitable for the BM235. The one on the left was purchase online  and the right it is the stock that it came. Lettering may be different but looking with eye position is the same if viewed from right to left endcap.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 18, 2019, 05:27:06 pm
It appears it came with the the Keysight meter.

What do you mean by "appears"? Did you personally unbox a new/sealed Keysight meter and remove that fuse from it?
I bought the Keysight meter from Keysight, brand new.  Yes I unboxed it and proceeded to test it to failure.  Very few meters I have looked at came with SIBA branded fuses.  Most that did, used the small body style.   The Keysight meter I bought did have a 10A large body and I had pulled the fuses when I scrapped the meter.  The pulled fuses get tossed into a bag.  There is only one 10A SIBA fuse in the bag.   But, I've ran many meters over the last couple of years and it's possible there was some other meter that came with SIBA branded fuses that I scrapped.   So I use the word appears because there is a chance that it came from something else.  I'm not sure what I would have done with the fuse from the Keysight though.   

I had made a series of videos where I modified a UT61E.  One of the things I had done was to replace the small fuse with the larger one using this SIBA fuse.  However, later changed out the shunt to allow using the meter at 20A and replaced the 10A fuse and back into the bag it went.   I can't seem to find any other videos showing the 10A fuse and am fairly confident of it's history.   

https://youtu.be/d6LTsaOqk30?list=PLZSS2ajxhiQDrk4o1Y45auwK7LomjnNBU&t=274
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 18, 2019, 06:43:34 pm
It appears it came with the the Keysight meter.

What do you mean by "appears"? Did you personally unbox a new/sealed Keysight meter and remove that fuse from it?
I bought the Keysight meter from Keysight, brand new.  Yes I unboxed it and proceeded to test it to failure.  Very few meters I have looked at came with SIBA branded fuses.  Most that did, used the small body style.   The Keysight meter I bought did have a 10A large body and I had pulled the fuses when I scrapped the meter.  The pulled fuses get tossed into a bag.  There is only one 10A SIBA fuse in the bag.   But, I've ran many meters over the last couple of years and it's possible there was some other meter that came with SIBA branded fuses that I scrapped.   So I use the word appears because there is a chance that it came from something else.  I'm not sure what I would have done with the fuse from the Keysight though.   

I had made a series of videos where I modified a UT61E.  One of the things I had done was to replace the small fuse with the larger one using this SIBA fuse.  However, later changed out the shunt to allow using the meter at 20A and replaced the 10A fuse and back into the bag it went.   I can't seem to find any other videos showing the 10A fuse and am fairly confident of it's history.   

https://youtu.be/d6LTsaOqk30?list=PLZSS2ajxhiQDrk4o1Y45auwK7LomjnNBU&t=274

Looking at the pictures I have taken over the years, the Gossen and CEM meters used the large SIBA 10A fuse.  However the Keysight meter does NOT!!!!   :-DD   It's a good thing I take pictures.  I forgot that meter does not even have current.   :-DD   I may need to retire from meter testing.

I still have these meters and could take high resolution pictures of each fuse if you like.    You would expect a Gossen meter would have a genuine SIBA fuse.  See attached.

So,  now that we know the fuse in question did not come from Keysight, where did this fuse come from?  I think there are two possible answers.  I had ran another CEM at one time and I think there was a Klein meter that may have had a large fuse as well.  I did not take pictures of these meters and would need to see if the videos show anything.

The ones I had purchased that I suspected were counterfeit were clearly marked different than the ones supplied with the meters.  They also behaved different when I compared the two.   
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on February 18, 2019, 06:48:53 pm
No comment on the third one I posted?

I'm not sure about that one. On the one hand I don't see why SIBA would have two types of markings but on the other I know that when you make a comment like that it's a trap.

There's a distinct lack of pictures of fuses on SIBA's web site to compare anything with.  :-//

I find Siba USA (http://www.siba-fuses.com/front_content.php?idart=121) very responsive to any questions.
It takes a while to get to the particular product manager and sometimes ends up bouncing around Germany.
They will micro-section to find any fakes or other issues. I guess it's something they do all the time, the only way to really check a fuse inside.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 18, 2019, 07:03:40 pm
Here are the original SIBA HRC 10kA fuses that came with my U1273A purchased new.

The printing is radically different between them.

The metallic ends are scrapped and scuffed both from factory and from my attempts to remove them from the meter (they are fit incredibly tight).

And sorry, I will not destroy them to see if they are fake.  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 18, 2019, 07:13:32 pm
Here are the original SIBA HRC 10kA fuses that came with my U1273A purchased new.

The printing is radically different between them.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=656295;image)

No kidding.

Food for thought...
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on February 18, 2019, 09:14:24 pm
rolled on with a stamp, maybe it's more reliable than ink-jets.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 18, 2019, 09:30:15 pm
At home I will check the Fluke ones I got many years ago (11A and 440/1000). I wonder if their printing is equally uneven.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 18, 2019, 09:57:36 pm
And here are the fuses for the UT 139A , purchased on a store, still packed ... not much difference from the 400mA on the markings


Edit: Ooppss time delay fused... crap...
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on February 19, 2019, 02:54:26 am
At home I will check the Fluke ones I got many years ago (11A and 440/1000). I wonder if their printing is equally uneven.

dont Fluke use LittleFuse? i think LittleFuse use printed labels stuck to the fuse.
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on February 19, 2019, 07:25:51 am
dont Fluke use LittleFuse? i think LittleFuse use printed labels stuck to the fuse.

On the two I have reviewed it is printed labels on the fuse:
289:
(https://lygte-info.dk/pic/Fluke/289/DSC_8455.jpg)
17B:
(https://lygte-info.dk/pic/Fluke/17B/DSC_1405.jpg)

Both from Bussmann

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 19, 2019, 11:06:26 am
At home I will check the Fluke ones I got many years ago (11A and 440/1000). I wonder if their printing is equally uneven.

dont Fluke use LittleFuse? i think LittleFuse use printed labels stuck to the fuse.
Looking at photos of the new ones I have looked at, the larger style fuse appears to be Mexican made Bussman's with a printed label and woven tube.  Some of the very old Flukes I've looked at had USA made Cooper Bussman Limitron's in them.  These also have a printed label and woven tube.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on February 19, 2019, 11:46:18 am
At home I will check the Fluke ones I got many years ago (11A and 440/1000). I wonder if their printing is equally uneven.

dont Fluke use LittleFuse? i think LittleFuse use printed labels stuck to the fuse.
Looking at photos of the new ones I have looked at, the larger style fuse appears to be Mexican made Bussman's with a printed label and woven tube.  Some of the very old Flukes I've looked at had USA made Cooper Bussman Limitron's in them.  These also have a printed label and woven tube.
Yes, that is the 44/100 I have here (the 11A is gone)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2019, 01:02:19 am
One thing I never understood is how they get away with putting a fuse only rated for 10KA in a CAT III and up meter?   I don't know of many fast blow fuses besides these from SIBA that are rated to 30KA.   

For me personally, it's not a big deal as the HIOKI meter I use in this environment does not use fuses. 
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on February 20, 2019, 01:28:49 am
so you have the one with the external current clamp?
i do like that feature.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2019, 01:56:10 am
The one I use is like that, yes but clamps.  I've shown a picture of it here somewhere.   
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on February 20, 2019, 02:03:17 am
One thing I never understood is how they get away with putting a fuse only rated for 10KA in a CAT III and up meter?   I don't know of many fast blow fuses besides these from SIBA that are rated to 30KA. 

That would be a robustness test which would be interesting to see. Basically, what happens if you take a meter on the 10 A current range and place the probes across the bus bars in the service panel of a typical house before the circuit breakers? (Academically of course, not suggesting to do it, unless someone has already put it up on YouTube...). Also, curious what would happen if this blew the supply company's service fuse? What would they charge to come out and fix it? And would they ask how it got blown? So many questions. Also, how long would the poles have to be to keep the operator at a safe distance from the meter?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2019, 02:30:42 am
Photonicinduction had made some pretty good videos on the high break current fuses using that huge cap he has.  It keeps the test off the lines and it's much harder to break the DC.     

All the CAT III rated meters I have looked at should be safe, right across the bus bars of a home, right??   Maybe have the head of marketing and a top manager from each company hold the meters while the test is performed with no PPE.   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 20, 2019, 03:00:10 pm
I was going to say that there's a video of a guy at fluke connecting a meter to 660V and twisting the selector dial back and forth, but AFAICT it's a meter with no current ranges:

https://www.youtube.com/watch?v=OEoazQ1zuUM (https://www.youtube.com/watch?v=OEoazQ1zuUM)


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 20, 2019, 05:47:16 pm
I was going to say that there's a video of a guy at fluke connecting a meter to 660V and twisting the selector dial back and forth, but AFAICT it's a meter with no current ranges:

 :-DD :-DD

I watched that AEV (AVE?) video where he looks at the non-contact Fluke fork and rants about how bad it is for an hour while trying to use a current monitor with it.  Lots of drama and just stupid.  Then I see him post about a cheap meter and compares it with a Fluke.  No big deal but he is talking about how safe the Fluke is, all the while with some fuse that he pulled from the local hardware store stuck in it.  If you are going to promote safety, seems like you would at least use a fuse rated for the AC/DC voltages and proper break currents....  |O 

I make mistakes in pretty much every video I put out but IMO these go beyond a simple mistake. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on February 20, 2019, 07:06:50 pm
Yes, AvE (Arduino vs. Evil).
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 20, 2019, 10:42:03 pm
I was going to say that there's a video of a guy at fluke connecting a meter to 660V and twisting the selector dial back and forth, but AFAICT it's a meter with no current ranges:

 :-DD :-DD

I watched that AEV (AVE?) video where he looks at the non-contact Fluke fork and rants about how bad it is for an hour while trying to use a current monitor with it.  Lots of drama and just stupid.  Then I see him post about a cheap meter and compares it with a Fluke.  No big deal but he is talking about how safe the Fluke is, all the while with some fuse that he pulled from the local hardware store stuck in it.  If you are going to promote safety, seems like you would at least use a fuse rated for the AC/DC voltages and proper break currents....  |O 

I make mistakes in pretty much every video I put out but IMO these go beyond a simple mistake.

Well this is not to contrast with the given facts but there is a difference between a safe meter and safe "human" procedures. if one fails you are compromising already the safety and in that case the "human" fails to grant the security of the meter and its own in further time.

To be honest i did a big mistake on purchased some fuses on a store in a rush but didn't pay attention to the label "T" of the SIBA fuses  which means time and multimeter requires F or FF :( Now they only serve for protection on a AC / DC project because karma is telling that they if placed on the meter it may blow it or the human ...


https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2210136/#msg2210136 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2210136/#msg2210136)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 22, 2019, 01:17:53 pm
The difference is you realized and understood you bought the wrong fuse.   

I made a video showing a small model dyno I constructed and used to help design a much larger system to evaluate a friends race car motors.   I used motor out of a child's toy to demonstrate it.  Apparently the people who play with these feel they are not toys and that I should know better than to call them such.   They felt I should have some clue about their hobby where I really have no interest.  Point being, we all have our areas that we will dive into.  After watching a couple of the other guys videos, I have the feeling he is just out of his element when he talks about electrical/electronics.

I was hoping to finish up my testing this weekend for the new meter but ran into a minor setback.  Parts are on order and should make it in next week.
Title: Re: Handheld meter electrical robustness testing.
Post by: HoracioDos on February 22, 2019, 04:33:44 pm
Also, curious what would happen if this blew the supply company's service fuse? What would they charge to come out and fix it? And would they ask how it got blown?
It's pretty common here. You can buy a 63A fuse and install it by yourself if you dare. Fuse box doesn't have any precinct. Just a plastic lever inside.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 22, 2019, 05:06:16 pm
I was hoping to finish up my testing this weekend for the new meter but ran into a minor setback.  Parts are on order and should make it in next week.

It died much too early?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 22, 2019, 06:28:13 pm
I was hoping to finish up my testing this weekend for the new meter but ran into a minor setback.  Parts are on order and should make it in next week.

It died much too early?

Two years of testing has taught me that the performance is not always proportional to the hype.   

To date, I have documented 59 meters.  This does not include a few like the Fluke 189.    In the first set of tests, the AMPROBE AM510 was damaged at 5.8KV which is basically what I call my cutoff point.   Make it above that level, you have a decent meter IMO.  We have 15 that meet that criteria or 25%.    If we include the Fluke 189 and assue that one 87V that I had repaired and reseted to be a flyer, then we have 17 out of 60 or 28.3%.   Of course, I have been running what I consider a better class of meter lately which biases the data.   

Of these, the brands that stand out are and Fluke and Brymen.  While the Gossen and HIOKI both did very well, I only looked at one product from these companies.  I have said that I use a HIOKI product for work and personally, that carries some clout after what I have put it through (transient wise).   We are not talking about these little piss ant transients I apply to benchmark these meters.   


Statistically speaking, I would say the meter I am looking at now ......   (you don't want me to spoil it for you, do you? lol)    Maybe we will have a new brand join the Flukes, Brymen's, HIOKI's and Gossens of the world.  It's big shoes to fill and requires you know how to design....  Maybe.... 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 22, 2019, 06:33:03 pm
you don't want me to spoil it for you, do you?

Nope.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 25, 2019, 11:51:36 am
Several people have asked me to look at Yokogawa.   In this video, I have a look at their top of the line TY720. 

https://youtu.be/4aCN-uLeO5s
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on February 25, 2019, 12:37:43 pm
At least we agree on the correct choice of calculator.  :)

Edit: Real SIBA fuses? The printing on them looked nice in the video, maybe some closeup images.

(or ware those the fuses you posted the other day?)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 26, 2019, 12:37:18 am
At least we agree on the correct choice of calculator.  :)

Edit: Real SIBA fuses? The printing on them looked nice in the video, maybe some closeup images.

(or ware those the fuses you posted the other day?)

I like this old HP calculator.  Anything more complex, I use the PC.   

I saved the fuse in case someone wanted more information about it.   I have no reason to suspect any of the large parts have been counterfeit.   If someone did want to make a knockoff, I would think they would directly crimp the end caps to the body like other cheap fuses we have looked at.   

In the comments, one person had posted about also seeing a fuse be intermittent.   Perhaps it's more common than I thought. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on February 27, 2019, 12:26:35 am
Hey seems that the DMM have some similar cousins,.. Kyoritsu KEW 1062 :

https://www.kew-ltd.co.jp/en/products/detail/00976/ (https://www.kew-ltd.co.jp/en/products/detail/00976/)

Copy cat?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 01, 2019, 05:09:59 pm
Joe, I am really sorry to see how this Yokogawa is really a far cry from the A-brand meters - one could do much better for the same price.

Given Malagas' find above, I really wonder if they OEM this.
Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 01, 2019, 05:22:46 pm
Hey seems that the DMM have some similar cousins,.. Kyoritsu KEW 1062 :

https://www.kew-ltd.co.jp/en/products/detail/00976/ (https://www.kew-ltd.co.jp/en/products/detail/00976/)

Copy cat?

From what I understand, they're made in the same factory for both Kyoritsu and Yokogawa.  Please see:
https://www.eevblog.com/forum/testgear/ty720-kew-1062-handheld-multimeter-inside-high-resolution-images/msg1491871/?topicseen#msg1491871 (https://www.eevblog.com/forum/testgear/ty720-kew-1062-handheld-multimeter-inside-high-resolution-images/msg1491871/?topicseen#msg1491871)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 02, 2019, 05:43:41 pm
FanOfeeDIY had asked me about running one (to the extend of offering to send one) of these meters some time ago and posted those pictures to give me some idea how it was designed.  He answered some questions I had as well which is really why I decided to run one.   

I did start a thread in the repair section for the meter.  I'm a bit too lazy to blindly start tracing the meter out but maybe someone else has some details about the design. 

https://www.eevblog.com/forum/repair/yokogawa-ty720-kyoritsu-kew1062-needs-repair/ (https://www.eevblog.com/forum/repair/yokogawa-ty720-kyoritsu-kew1062-needs-repair/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2019, 05:49:08 am
After several of hours of tracing all these analog switches and multiplexers, I now know way more than anyone should ever have to about the TY720.   The board is filled with colored markers and now needs a good cleaning.   

To Yokogawa,   :--
Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 03, 2019, 07:21:39 am
What's that capacitor doing there?
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 03, 2019, 11:38:06 am
What's that capacitor doing there?

I believed is being measured by the meter, a 25uF part,  before it gets totally assembled , clean and dry. This way you wont get more surprises to avoid further taking apart
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2019, 04:11:03 pm
What's that capacitor doing there?

I believed is being measured by the meter, a 25uF part,  before it gets totally assembled , clean and dry. This way you wont get more surprises to avoid further taking apart

Indeed, it was a cap that I was using to test the meter.   Shown, the board after some cleaning.  I have had the shield off three times so far and not seeing a problem with the two solder joints.  Showing the 10uF cap in my test box.   After changing out the analog switches and repairs, the meter needs to be realigned.   

Someone had asked if it was possible that the zebra strip was causing the bad contrast.   No.

Someone else asked about a contrast adjustment.  Yes, there is.  The problem is the contrast is already high enough that segments that are turned off are bleeding through. 

Another person attempted to read a biased AC voltage and was able to repeat what I saw with this meter.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 03, 2019, 04:42:54 pm
After several of hours of tracing all these analog switches and multiplexers, I now know way more than anyone should ever have to about the TY720.
I feel your pain. I started to extract the schematics of the Surpeer AV4 and suddenly the same thought came to my mind. I then closed everything and sold it for the same price I paid (with all the proper disclaimers, of course).

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 03, 2019, 04:59:05 pm
Jesus did i wrote 25uF??? i mean t22uF :P Sorry. It was off then but now looks very accurate, and a lot hard work invested in cleaning that flux . Did you also touched some solder joints? they look very shinny.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2019, 05:16:10 pm
After several of hours of tracing all these analog switches and multiplexers, I now know way more than anyone should ever have to about the TY720.
I feel your pain. I started to extract the schematics of the Surpeer AV4 and suddenly the same thought came to my mind. I then closed everything and sold it for the same price I paid (with all the proper disclaimers, of course).

I was really hoping someone would show up with the schematic for it.  It would have been a quick repair then.   I could have left it damaged but I have made a point to attempt to troubleshoot the meters that are damaged during the testing.   With this meter using mostly standard parts, I was confident it could be repaired if I wanted to invest the time.  The spaghetti design added to the challenge.  In the big scheme of making the video, it wasn't too bad. 

I looked at buying one of the AV4 meters but from the pictures I saw, it looked like it had no protection, similar to the ANENG meters I have looked at.  That OWON I looked at did a fair job functionally.  Had the Bluetooth interface been documented,  better input protection and some proper fuses, it would make a nice meter lower cost meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 03, 2019, 05:20:59 pm
Did you also touched some solder joints? they look very shinny.
When it was all said and done, I had removed and reattached 13 ICs and several other parts.   I did blend in some 60/40 on the tabs for the shield to lower the temp.  The rest, I just added flux and reflowed the parts.  My PACE tweezers and heat gun were getting a work out.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 07, 2019, 04:05:53 am
The correct parts arrived for the Yokogawa today.  Seems to be in cal.   

https://youtu.be/Q9JhJm_dTPM
Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 07, 2019, 12:18:19 pm
Watched the video but you only touched on the real issue... it was a fuse, but it wassn't one of the two main fuses?  Or was it?  You have us all in suspense  :-DMM ???
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 07, 2019, 06:22:39 pm
Watched the video but you only touched on the real issue... it was a fuse, but it wassn't one of the two main fuses?  Or was it?  You have us all in suspense  :-DMM ???

The meter did have what appeared to be a defective SIBA branded fuse that I replaced early on.   I don't feed the transients into the current inputs of the meter so no, the damage to the capacitance mode had nothing to do with my changing out that fuse.   That was a completely separate problem. 

Normally on the better class of meters, the high speed clamps will fail and save the down stream components.  On the low end meters, normally something else in front of the clamp (normally the PTC) will brake down and it's game over.   In this case, the entire front end checked out.  This may be a first.   It also tells me that the meter could use some improvements.   It has enough other problems that it's hardly worth spending more time on though. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 07, 2019, 07:45:25 pm
Here is another Japanese meter that may look interesting:

https://overseas.sanwa-meter.co.jp/items/detail.php?id=13 (https://overseas.sanwa-meter.co.jp/items/detail.php?id=13)

It has nano siemens at least :P but the contrast seems a little dim from the catalog and pictures.

[Edit]

Not a newer model for sure.... it has been reviewed and digits are more slim but not too dimmed . Capacitance reading is quite fast

https://www.youtube.com/watch?v=b_0UCFekSYs (https://www.youtube.com/watch?v=b_0UCFekSYs)
Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 07, 2019, 08:26:04 pm
The meter did have what appeared to be a defective SIBA branded fuse that I replaced early on.   I don't feed the transients into the current inputs of the meter so no, the damage to the capacitance mode had nothing to do with my changing out that fuse.   That was a completely separate problem. 

Normally on the better class of meters, the high speed clamps will fail and save the down stream components.  On the low end meters, normally something else in front of the clamp (normally the PTC) will brake down and it's game over.   In this case, the entire front end checked out.  This may be a first.   It also tells me that the meter could use some improvements.   It has enough other problems that it's hardly worth spending more time on though. 

I sense that Kyoritsu/Yokogawa designed that meter to be built with low cost parts and low-cost labor (Thailand) to maximize profit.
AFAIK Hioki is the only Japanese brand that still make their meters in Japan with their own ICs.  Hioki LCDs seem to have the best readability from extreme vertical angles (from below and above).



.



Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 07, 2019, 08:43:08 pm
Here is another Japanese meter that may look interesting:

https://overseas.sanwa-meter.co.jp/items/detail.php?id=13 (https://overseas.sanwa-meter.co.jp/items/detail.php?id=13)

It has nano siemens at least :P but the contrast seems a little dim from the catalog and pictures.

[Edit]

Not a newer model for sure.... it has been reviewed and digits are more slim but not too dimmed . Capacitance reading is quite fast


I can't get past the Sanwa PC7000 aesthetics... but what is interesting is the 500,000 count DCV mode, and its low cost ($270 shipped from Japan). 
I think its manufactured in China.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on March 07, 2019, 11:22:07 pm
I think that one is based on Brymen BM867. It even uses same pc cable
.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on March 08, 2019, 12:16:57 am
Spotted in another thread:
A poor little Brymen being asked to check the EHT voltage in a Tek CRO.  :scared:

(https://i.imgur.com/44r6SGp.jpg)

Only a couple of times its rated voltage.  :-DD
Recommended, NO. Impressive YES !
Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 08, 2019, 12:20:36 am
I think that one is based on Brymen BM867. It even uses same pc cable
.
Hey you're right, layout is nearly identical, except Sanwa PC7000 has a temperature setting on the rotary.
So, call is a BM867+?  ;D   Oh now that I think about it, I seem to recall seeing reviews of different Sanwa meters, where the box said "Made in Taiwan."  Maybe Brymen makes meters for them?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2019, 01:33:20 am
Spotted in another thread:
A poor little Brymen being asked to check the EHT voltage in a Tek CRO.  :scared:


Only a couple of times its rated voltage.  :-DD
Recommended, NO. Impressive YES !

 :-DD :-DD :-DD   I continue to abuse the little pocket Brymen that member True posted about.  After everything I have done to this meter, it would be fun to take Dave's SANWA and have my own shoot out.   A badly abused Brymen vs a brand new Sanwa.   :box:   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2019, 01:43:50 am
I sense that Kyoritsu/Yokogawa designed that meter to be built with low cost parts and low-cost labor (Thailand) to maximize profit.
AFAIK Hioki is the only Japanese brand that still make their meters in Japan with their own ICs.  Hioki LCDs seem to have the best readability from extreme vertical angles (from below and above).

I doubt there is much labor in these meters once the the line is setup.  They may have just wanted a design they could maintain.   Akira Tsukamoto would need to chime in.

Personally, the display that for me has been the most memorable is the UNI-T UT181A.  That color just pops.  The worst display I have seen was by far my old Fluke 97 scope meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 08, 2019, 02:33:15 am
I sense that Kyoritsu/Yokogawa designed that meter to be built with low cost parts and low-cost labor (Thailand) to maximize profit.
AFAIK Hioki is the only Japanese brand that still make their meters in Japan with their own ICs.  Hioki LCDs seem to have the best readability from extreme vertical angles (from below and above).

I doubt there is much labor in these meters once the the line is setup.  They may have just wanted a design they could maintain.   Akira Tsukamoto would need to chime in.

Personally, the display that for me has been the most memorable is the UNI-T UT181A.  That color just pops.  The worst display I have seen was by far my old Fluke 97 scope meter.

The newer meters with TFT or OLED displays look phenomenal compared to the standard LCD... I also like what Aneng did with their Q1, with reverse backlit LCD.  I know Dave doesn't like it but I sure do.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2019, 02:04:07 pm
The newer meters with TFT or OLED displays look phenomenal compared to the standard LCD... I also like what Aneng did with their Q1, with reverse backlit LCD.  I know Dave doesn't like it but I sure do.

I watched that video and thought that he was concerned with the short battery life with having to drive the back light.  Function over form, which I tend to agree with.  I would need to go back and watch it again. 

With the stories of short life, unable to view in outside light, I doubt I would ever own an OLED meter.  The 181A does look nice but has a pretty short battery life.  Of course, it uses a non-standard battery and you can't use the meter while it charges.  To me this would be a problem if it were my only meter.  At some point, the battery will fail and I will need to sort out a replacement.  Maybe print a new cover for it using AAs.   That sounds safe.   :palm: :-DD    It is a nice looking meter.  The components they used look good.  Layout is lacking.   Not real impressed with their choice of materials.  LCD is easy to scratch etc...   Could be a really nice meter, but you know, I say that about every meter!!   :-DD

 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 08, 2019, 04:28:18 pm
The newer meters with TFT or OLED displays look phenomenal compared to the standard LCD... I also like what Aneng did with their Q1, with reverse backlit LCD.  I know Dave doesn't like it but I sure do.

You must hate batteries.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 08, 2019, 04:46:11 pm
Hi

here is a follow up the comment on the video on the timing between videos where the measuring  + settle time were improved for 150pF capacitor by using a chronograpth. Starting point begins when placing leads on terminals and stop when value is stable


 I exagerated the counting on the first video of the yokogama by stop the chronograph only when you spoke which was 11.44s.
Now these are the new counting stoping right on the stable value and there might be aditional error of course.

- Original : 9.66s
- Improved: 8.69s




Chronograpth is decimal memory capable.

[Edit] : Sorry wrong / duplicated image
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2019, 06:25:26 pm
I have explained to you that I have not changed the meter's design and the repairs I made would not effect the settling time.  A picture of a stop watch doesn't provide any backup of your claim.   As I said, if you wanted to prove there was a change, you would need to line up the two videos and compare them.   Your claim of 1.5x times (7.81s vs 11.44s) should tell you that you are doing something wrong. 

So rather than spend more time trying to explain it to you, here are the two videos sync'ed.   

https://www.youtube.com/watch?v=FNU_G77rRQ0&feature=youtu.be (https://www.youtube.com/watch?v=FNU_G77rRQ0&feature=youtu.be)



Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 08, 2019, 06:52:18 pm
Thanks a lot for the syncing ,no need to explain more  ... i perceived wrongly "have" from "haven't" on the Yokogawa update video and kept the wrong idea all the way over  and over, :palm:

Title: Re: Handheld meter electrical robustness testing.
Post by: sambonator on March 08, 2019, 08:57:03 pm
The newer meters with TFT or OLED displays look phenomenal compared to the standard LCD... I also like what Aneng did with their Q1, with reverse backlit LCD.  I know Dave doesn't like it but I sure do.

You must hate batteries.

To the contrary, I love batteries... I keep buying them... many of them... frequently....  :-DD

Is that you Fungus loving my old battery?
(http://4.bp.blogspot.com/-9ZiMKYf5Q2E/T57N8gkj8wI/AAAAAAAAAEc/5KvmkormIk4/s1600/Leaky+Battery+4.jpg)

 :scared: >:D :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 08, 2019, 09:11:19 pm
If that's the expire date then expect the worse :P  They all may leak... at least its written on the back of the casing. The OLED in the Q1 doesn't seem quite good compared to an 8008, doesn't mean that other OLED based meters are worse for example the Agilent / Keysight U1253A looks very nice... but remember power hungry display :P

https://youtu.be/Zele19jm1MQ?t=673

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 08, 2019, 10:58:53 pm
Thanks a lot for the syncing ,no need to explain more  ... i perceived wrongly "have" from "haven't" on the Yokogawa update video and kept the wrong idea all the way over  and over, :palm:

You may have indeed misunderstood and had the wrong ideas but I have no clue where you came up with that 1.5X factor or what you were showing with that stop watch.   It was pretty obvious the settling times were not effected as I had explained. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 09, 2019, 12:00:08 am
Thanks a lot for the syncing ,no need to explain more  ... i perceived wrongly "have" from "haven't" on the Yokogawa update video and kept the wrong idea all the way over  and over, :palm:

You may have indeed misunderstood and had the wrong ideas but I have no clue where you came up with that 1.5X factor or what you were showing with that stop watch.   It was pretty obvious the settling times were not effected as I had explained.

Since i got confused i may crystallized the idea and tried  between the two videos find the difference. The start point is the same but stop is wrong because stopped when you started talked about the values and that made the difference. Yeah insisted in the wrong ideia....  blinding the obvious...   |O
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 09, 2019, 02:11:33 am
Since i got confused i may crystallized the idea and tried  between the two videos find the difference. The start point is the same but stop is wrong because stopped when you started talked about the values and that made the difference. Yeah insisted in the wrong ideia....  blinding the obvious...   |O

Blinded by the obvious  :-DD :-DD :-DD

When I watch some of my videos, I will catch myself at times making the same error over and over.  Some of these can be pretty funny.  It's odd that after the fact, the brain has no problem picking it out.  I have also constructed things wrong, over and over.  Some could be very simple.  Its strange. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 22, 2019, 03:05:48 pm
If that's the expire date then expect the worse :P  They all may leak... at least its written on the back of the casing. The OLED in the Q1 doesn't seem quite good compared to an 8008, doesn't mean that other OLED based meters are worse for example the Agilent / Keysight U1253A looks very nice... but remember power hungry display :P
Malagas, just keep in mind the Q1 is not OLED but instead a reverse plain LCD.
Also, the U1253A/B are more prone to OLED self-destruction than the newer U1273A - at least there are only one or two reports on the latter model about OLED durability, while the former has tens of reports.
(disclaimer: I have a U1273A and it is already five years old since mfg date - its OLED is still in pristine condition).
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 22, 2019, 03:41:00 pm
Oppss it's even worse??? I thought it was an OLED LCD  :P 5 years is a young meter as long as you don't expose much heat, it will last more years. Currently working with two U1251 A /B models at work and one (A) of them has the plastic of the rotary switch ripped off ( maybe too exposure to sunlight). They work fine , are super simple to use accurate in the sense it doesn't requre much calibration over the years.

One thing i've noticed at home during some experiments with electronics using AC 230V with isolation transformer, the meters BM235 e UT139A measuring V / A ( vice-versa) of the circuit.  would display OL when mangled the contacts from old plugs. it does create arcs and maybe AC transients in lower energy (about 6VA ) and trigger the OL situation on the meter. It doesn't matter if i swap the meters for A and other for V . To disable the OL of course it is required to turn off. the units.
 I didn't repeat the experience to avoid any potential damage to meter or DUT or even me and used better plugs.

is this some sort of protection implemented on the meters?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 22, 2019, 05:41:07 pm
Oppss it's even worse??? I thought it was an OLED LCD  :P 5 years is a young meter as long as you don't expose much heat, it will last more years. Currently working with two U1251 A /B models at work and one (A) of them has the plastic of the rotary switch ripped off ( maybe too exposure to sunlight).
Sunlight and heat destroy anything. Last summer I was fixing my pool equipment and my trusty Fluke 27/FM was under the sunlight for about 15min or so. It was facing down when I was not using it, so the LCD wouldn't become dark but, even still, its display became faded. It only came back to normal when I reseated and cleaned the zebra strips.

One thing i've noticed at home during some experiments with electronics using AC 230V with isolation transformer, the meters BM235 e UT139A measuring V / A ( vice-versa) of the circuit.  would display OL when mangled the contacts from old plugs. it does create arcs and maybe AC transients in lower energy (about 6VA ) and trigger the OL situation on the meter. It doesn't matter if i swap the meters for A and other for V . To disable the OL of course it is required to turn off. the units.
 I didn't repeat the experience to avoid any potential damage to meter or DUT or even me and used better plugs.

is this some sort of protection implemented on the meters?
I suspect the arcs may be shooting the voltage to very high levels. That or the meters are susceptible to high frequency transients.

Some meters, even from reputable manufacturers such as HPAK, showed this behaviour. The major issue is that there are usually several tradeoffs when designing the input section of a multimeter: safety level, noise/sensitivity, bandwidth...

This is only solved by a very good and well tested design.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on March 22, 2019, 06:15:05 pm
I have a Brymen BT-75 voltage tester. It works great. It will auto switch on when you connect tips for continuity test. It will actually auto switch on when you probe few hundred kiloohms.
It has dark case. I left it in the sun last summer. The PTC based low Z circuit in front end heated enough for it to start leaking enough to switch on tester just laying there in the sun.. Still works normally but kept switching on by itself..  So back in the toolbox it went..
Sun is strong here...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 22, 2019, 08:15:11 pm
Oppss it's even worse??? I thought it was an OLED LCD  :P 5 years is a young meter as long as you don't expose much heat, it will last more years. Currently working with two U1251 A /B models at work and one (A) of them has the plastic of the rotary switch ripped off ( maybe too exposure to sunlight).
Sunlight and heat destroy anything. Last summer I was fixing my pool equipment and my trusty Fluke 27/FM was under the sunlight for about 15min or so. It was facing down when I was not using it, so the LCD wouldn't become dark but, even still, its display became faded. It only came back to normal when I reseated and cleaned the zebra strips.

One thing i've noticed at home during some experiments with electronics using AC 230V with isolation transformer, the meters BM235 e UT139A measuring V / A ( vice-versa) of the circuit.  would display OL when mangled the contacts from old plugs. it does create arcs and maybe AC transients in lower energy (about 6VA ) and trigger the OL situation on the meter. It doesn't matter if i swap the meters for A and other for V . To disable the OL of course it is required to turn off. the units.
 I didn't repeat the experience to avoid any potential damage to meter or DUT or even me and used better plugs.

is this some sort of protection implemented on the meters?
I suspect the arcs may be shooting the voltage to very high levels. That or the meters are susceptible to high frequency transients.

Some meters, even from reputable manufacturers such as HPAK, showed this behaviour. The major issue is that there are usually several tradeoffs when designing the input section of a multimeter: safety level, noise/sensitivity, bandwidth...

This is only solved by a very good and well tested design.


Thanks for the information.  Don't have test gear to measure the voltage spike in a controlled manner .. if any-- so the best way was to prevent using decent plug connectors which is convinent in AC mains for the sake of the meters, circuits, triacs. and human :P I believe that BM235 was sensitive to the MSD system that joeqsmith use to shield the Gossen Metrawatt Metrahit. ( Sorry edit: to test he automotive Multimeter AIOESON??? EM135)

https://youtu.be/q_89qoFMivg?list=PLZSS2ajxhiQBvWvqMVLdRQMjGofKpQUJr&t=3458
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 23, 2019, 12:54:55 am
I have a Brymen BT-75 voltage tester. It works great. It will auto switch on when you connect tips for continuity test. It will actually auto switch on when you probe few hundred kiloohms.
It has dark case. I left it in the sun last summer. The PTC based low Z circuit in front end heated enough for it to start leaking enough to switch on tester just laying there in the sun.. Still works normally but kept switching on by itself..  So back in the toolbox it went..
Sun is strong here...

Odd as the PTCs resistance will increase with temperature.   Perhaps something else is happening.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 23, 2019, 04:49:02 pm
I mentioned I had two other videos in the works.  One is some long term testing I have been doing on the Brymen pocket meter that member True had claimed to have so many fail.   I would say its at least another month out.   

In the past, I have had to test some of my designs for vibration.  These were typically larger/heavier than a handheld meter and I would suggest a more harsh environment than a typical meter would ever see.   I am thinking I may try to come up with some sort of simple test jig to run a few meters on and may start with this little pocket meter.    I suspect mostly they see the drop or maybe low frequency low displacement.  I have not found any standards yet that companies have followed.   

Watching a few videos on the subject.  This one is pretty decent. 
https://www.youtube.com/watch?v=1vB1W-eO2BU (https://www.youtube.com/watch?v=1vB1W-eO2BU)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 23, 2019, 11:55:42 pm
Can we put the pocket brymen on Mars ?

NASA provides some basic info on their tests, not standard of course, their own purposes. Funny thing  if pocket brymen would survive all NASA could throw out :D

https://www.nasa.gov/centers/johnson/pdf/639713main_Vibration_Testing_FTI.pdf (https://www.nasa.gov/centers/johnson/pdf/639713main_Vibration_Testing_FTI.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2019, 01:17:29 am
My first attempt to make a cheap table for testing meters, made from four small speakers.   A few problems I see with it is that the stroke is only about 3mm and the frequency response will be pretty limited.   

I did some testing with it to see how much force it could generate and it can easily lift the BM869s at DC.  As the frequency goes up, it looses a lot of travel.   

It appears others have been down this path....
https://pdfs.semanticscholar.org/ae56/0d0290985ec64fb901c3cdb5970c17d52514.pdf
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 24, 2019, 11:48:11 am
About the NASA i was just joking.

That is the first search result on "floggle" for "vibration text fixture homemade". Super simple circuit and using and a new device such as the dongle USB joule thief mentioned as example and the more easy cheap MEMS  :P

In the paper for the MEMS they appear to put a plastic structure direct on the center hole. Does you're upper table is close enought to the subwoofers?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on March 24, 2019, 12:24:35 pm
Be sure to put some screwdrivers in the box when you're shaking it.

Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 24, 2019, 12:41:34 pm
Spotted in another thread:
A poor little Brymen being asked to check the EHT voltage in a Tek CRO.  :scared:


Only a couple of times its rated voltage.  :-DD
Recommended, NO. Impressive YES !

 :-DD :-DD :-DD   I continue to abuse the little pocket Brymen that member True posted about.  After everything I have done to this meter, it would be fun to take Dave's SANWA and have my own shoot out.   A badly abused Brymen vs a brand new Sanwa.   :box:

Original poster of the BM22s torture. It got up to around 2Kv then made some unpleasant noises, i assume the spark gaps going in it. I let it go for a few seconds. No measurement problems or damage afterwards I could identify.

Also indeed recommended no, but I didn't fancy putting the 87V near that one and the proper 40Kv probe was buried in the back of the junk cupboard somewhere. Seeing as I have five of these BM22's now (I get them free every time I buy something Rigol) I figured I'd see what it was capable of.

Incidentally no I wasn't in contact with the device while testing. That would be insane. I actually soldered the probe tips to the HT parts of the board and powered up remotely.

They are very handy little meters. I pop one in my pocket every time I go to a hamfest to test things before I buy.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2019, 04:19:08 pm
Original poster of the BM22s torture. It got up to around 2Kv then made some unpleasant noises, i assume the spark gaps going in it. I let it go for a few seconds. No measurement problems or damage afterwards I could identify.

Also indeed recommended no, but I didn't fancy putting the 87V near that one and the proper 40Kv probe was buried in the back of the junk cupboard somewhere. Seeing as I have five of these BM22's now (I get them free every time I buy something Rigol) I figured I'd see what it was capable of.

Incidentally no I wasn't in contact with the device while testing. That would be insane. I actually soldered the probe tips to the HT parts of the board and powered up remotely.

They are very handy little meters. I pop one in my pocket every time I go to a hamfest to test things before I buy.

Wait, are you saying your afraid to use what I understand is the "gold standard" of meters because your concerned it will become damaged with something a cheap pocket meter can survive???  :-DD :-DD     

Silicone is dry enough to try some tests.   Shown running open loop.  The scope is showing the plate's position as it is swept from 10 to 300Hz.  Its far from flat. 

This paper talks about MIL-STD-810.  Figure 2 shows the displacement vs frequency for a helicopter.   

https://www.desolutions.com/blog/2017/05/mil-std-810-vibration-testing-category-24-minimum-integrity-tests-mit/ (https://www.desolutions.com/blog/2017/05/mil-std-810-vibration-testing-category-24-minimum-integrity-tests-mit/)
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 24, 2019, 04:53:30 pm
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 24, 2019, 09:22:00 pm
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Your post is a testament to Brymen's robustness.     

I keep my first LeCroy DSO for that same reason.   When it comes to the handhelds, I have no problems abusing them for the benefit of others.   It's really their main purpose.  I had ran a long term high voltage test on the 87V to show the effects on the MOVs.   I didn't take it up to the same voltage level you have.       

https://youtu.be/dQPcAs0EEqY
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 25, 2019, 12:03:09 am
Joe, you'd give Dave recursive nightmares about spitting on contacts.. then again, he's a rock that probably sleeps like one  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 25, 2019, 02:24:31 am
Joe, you'd give Dave recursive nightmares about spitting on contacts.. then again, he's a rock that probably sleeps like one  :-DD

I doubt it.  As Dave posted recently, we tend to deal in facts.  Show me some concrete data without yellow sticky notes with equations no one can make sense of and I may not run it..... No... I would still run it.   

Engineers are incredibly easy to shut up, they deal in facts, just show them concrete data and it's done.

If you don't have concrete data to show your device works and/or is practical, then it's not unexpected for people to call you things when you work in this sort of field. Because there are countless crackpots and tesla-nuts out there, the internet is filled with them, and many startup companies have stolen a lot of peoples money. People have good reasons to be very skeptical.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 25, 2019, 02:33:14 am
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Your post is a testament to Brymen's robustness.     

I keep my first LeCroy DSO for that same reason.   When it comes to the handhelds, I have no problems abusing them for the benefit of others.   It's really their main purpose.  I had ran a long term high voltage test on the 87V to show the effects on the MOVs.   I didn't take it up to the same voltage level you have.       

https://youtu.be/dQPcAs0EEqY

Dang, rewatched that part and it looks like I had the 87V even higher than your Brymen for days.  That was a week long test!!  :-DD 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 25, 2019, 10:53:47 pm
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD

Next time would be to put two meters in series  to increase impedance to measure HV.... and maybe you will double the problems :P Or get two new ones:

https://www.youtube.com/watch?v=bgz-pqg0rKo (https://www.youtube.com/watch?v=bgz-pqg0rKo)
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 25, 2019, 11:09:18 pm
That's not a bad idea actually. Would probably work  :-DD

I've got 5 of them now. That's 50 meg and <10KV in theory ... hmmm  :scared:

(no I'm not going to do it - I found my 40KV probe now  :-DD)
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 25, 2019, 11:14:15 pm
I think it’s more I’d cry if I blew up the 87V. If the BM22s blew up I’d throw it in the bin and get another one out  :-DD
Your post is a testament to Brymen's robustness.     

I keep my first LeCroy DSO for that same reason.   When it comes to the handhelds, I have no problems abusing them for the benefit of others.   It's really their main purpose.  I had ran a long term high voltage test on the 87V to show the effects on the MOVs.   I didn't take it up to the same voltage level you have.       

Totally agree with the Brymen's robustness. I was honestly surprised. I've got a cheap DT830 floating around I will chuck across that HT divider next time and see what happens. That was a Farnell reject apparently. The display wasn't seated properly so it didn't work. I repaired it. Bet that'll blow up!

WRT the 87V, I tend to treat the HRC fuse, MOVs etc as "last resort". That's what will stop you getting toasted on a transient or a stupid error. For daily use I expect them to work ONCE to save my butt. That's worth a new meter. New me is not an option. I don't care if they survive or not.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 25, 2019, 11:41:53 pm
WRT the 87V, I tend to treat the HRC fuse, MOVs etc as "last resort". That's what will stop you getting toasted on a transient or a stupid error. For daily use I expect them to work ONCE to save my butt. That's worth a new meter. New me is not an option. I don't care if they survive or not.

Oh, I get it.  Use cheap meters so the "gold standard" stays preserved as the shelf princess it is.   :-DD 

I doubt you will get enough energy from a CRO to blow up an 87V and kill you in the process.   On the 87V if it leaves the shelf, how would you ever know if it was stressed?  Buy a new one after each use?  Have a scope out and capture anything that happens to know what it was exposed to?  Send it to Fluke for some sort of annual inspection, MOV replacement? 

I never work on high energy circuits with my hobby so I have little concern something would ever blow up and kill me.   But I do have concerns that a meter would survive some basic transients.   Which is really the whole point of this long drawn out thread....
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 25, 2019, 11:52:35 pm
CRO for sure. The Fluke if stressed I’d expect to see functional failure somewhere.

I occasionally have to poke around on cat III three phase UPS / DC busbar installations at which point the 87V comes with me. This is mainly a blame establishing process at which point the “professional” electricians come in and we have grounds to disagree with them when they feed us a load of bollocks and an unrealistic quote  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 26, 2019, 12:45:06 am
Yea, I know what that's like.  I've had to venture into the world of CAT III now and then.  When it comes up, something is going on and I will need something more than a basic meter so I take that HIOKI with me.   I'm not an electrician but have some idea what I am doing, and I use clamps so fairly low risk.  Also, the voltages/currents are fairly low.  The first person I want to talk to is their master electrician.   I've had some pretty insightful conversations with a few of them,  especially if I keep them in the loop while I am working.     

I had HIOKI come in and demo the first meter I started using.  They left it with me to try out.  We surge tested it for real, not these little transients that I show in my home videos.   They come at a price but I do like their products.  Then again, I tried to contact them from my home email account and could never get them to respond. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 26, 2019, 02:14:05 am
Dancing Dope

https://youtu.be/1Q66mXqlvoY
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 26, 2019, 03:07:04 am
I used to work for a company that had a magnesium table for vibration testing (http://www.sci-lab.com/SLvibration.php). I guess that's gotta be the duck's gut's for stress, but how do you plan to integrate this into your already detailed scope of tests?
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on March 26, 2019, 03:43:29 am
In the past, I have had to test some of my designs for vibration.  These were typically larger/heavier than a handheld meter and I would suggest a more harsh environment than a typical meter would ever see.   I am thinking I may try to come up with some sort of simple test jig to run a few meters on and may start with this little pocket meter.    I suspect mostly they see the drop or maybe low frequency low displacement.  I have not found any standards yet that companies have followed.   

There are vibration standards for both ground (truck/rail) and air transport (the transportation of the product is a necessity and known quantity, unlike end-user requirements). I used to test gear against this with custom jigs, but it was a long time ago so don't recall the standards off-hand.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 26, 2019, 03:57:42 am
In the past, I have had to test some of my designs for vibration.  These were typically larger/heavier than a handheld meter and I would suggest a more harsh environment than a typical meter would ever see.   I am thinking I may try to come up with some sort of simple test jig to run a few meters on and may start with this little pocket meter.    I suspect mostly they see the drop or maybe low frequency low displacement.  I have not found any standards yet that companies have followed.   

There are vibration standards for both ground (truck/rail) and air transport (the transportation of the product is a necessity and known quantity, unlike end-user requirements). I used to test gear against this with custom jigs, but it was a long time ago so don't recall the standards off-hand.
Some of those standard's may be listed in the PDF here: http://www.sci-lab.com/2743-01.pdf (http://www.sci-lab.com/2743-01.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 26, 2019, 12:02:09 pm
I used to work for a company that had a magnesium table for vibration testing (http://www.sci-lab.com/SLvibration.php). I guess that's gotta be the duck's gut's for stress, but how do you plan to integrate this into your already detailed scope of tests?
We had similar tables, some that were the floor of the environmental chambers.  It's a bit overkill for the home lab.   :-DD

Like my transient and life cycle testing, I will most likely try a couple of meters and see how they behave.  Basically look for some resonate points to get some idea on the frequency range and displacement.  Once I have something that is close to what I am looking for,  make a video and see what sort of feedback I get. I need to come up with some generic way to secure the various meters in 3 axis before I can try it.  Also, I am just starting to look at how to control it.     

The weight of the meters and sound level will limit what I can do with this setup.   The switch life cycle tests are pretty bad when you have a meter like the Fluke 87V gold standard that starts to grind.  No one wants to listen to that for days on end.  This would be much worse. 

There are some meters I'm a bit concerned with.   The 121GW has the unsupported card holder that I can see cracking pretty easily for example.   A lot of meters will lay fairly large alumelec on the board without support.   Some meters I have used the old stand up TH designs. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 26, 2019, 12:30:53 pm
For those vivration tests, I would love to see how Fluke tests a meter such as the 28 II EX - I heard it is potted inside.
Title: Re: Handheld meter electrical robustness testing.
Post by: mqsaharan on March 26, 2019, 06:32:05 pm
For those vivration tests, I would love to see how Fluke tests a meter such as the 28 II EX - I heard it is potted inside.

It will of course be very interesting to see vibration tests on different multimeters and especially Flukes. Because they have removed the "Vibration" and "Shock" heads from the specifications of their multimeters in current revisions. Either they feel no more confident or the requirements have gone more stringent.

28 II Ex is partially potted. You can take a look at it in the following video from MJLorton, about 13:10 minutes in where he does a teardown.

https://www.youtube.com/watch?v=GDsVQVwGbq4 (https://www.youtube.com/watch?v=GDsVQVwGbq4)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 27, 2019, 02:49:21 am
First attempt to run the table closed loop.   The top graph is showing the displacement in mm vs frequency in Hz.  The control signal was set to 1mm.   The lower graph, green trace is showing the integral term.  The vertical scale is in volts.  The Arb is driving the power amplifier.  A LVDS is used to sense the table's position.   At 37Hz, it was starting to roll off.  It was also getting a bit too loud which is why I aborted the test.      The sweep time was fairly short and the tune was a swag.   

I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on March 27, 2019, 09:24:36 pm
I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD
Yes, I think this is a great exercise but, differently than your rotary test or even the transients, it is much harder to translate a constant vibration pattern to a real world scenario. A constant vibration table seems closer to leaving the meter on top of a car's engine or the washing machine in a cycle spin, but it can barely translate to the G forces subjected by falls, for example.

However, we do what we got to do.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 27, 2019, 11:48:26 pm
I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD
Yes, I think this is a great exercise but, differently than your rotary test or even the transients, it is much harder to translate a constant vibration pattern to a real world scenario. A constant vibration table seems closer to leaving the meter on top of a car's engine or the washing machine in a cycle spin, but it can barely translate to the G forces subjected by falls, for example.

However, we do what we got to do.

I don't see it being any different than other tests I have ran.   I don't try to come up with real world scenarios but rather some standard way that they can be evaluated to compare their performance.    I could for example find some obscure circuit that was once use that causes some transient that may damage a meter.   If I adopt that as my standard, I can only tell what meters survive it.  Not how much more they could take or how close the ones were that failed.   The rotary switch life test is similar.  I keep track of the contact resistance to get an idea of how the meters perform while they are being cycled.   One way would be to take the meter apart during the test and spit shine the contacts to see how they are wearing.   

I would like to weed out the better class of meters, just like I have done with every other test.    In this case, I could have different profiles.  That's a ways out.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 28, 2019, 12:01:40 am

I can see the posts now, "I've owned that meter for 10 years and its never had a problem. "    :-DD :-DD


I have a uni-t for 50b for 10 years and had problems like burn 500mA fuses, almost neutralized the Amps shunt while poking UPS outlet ( saved by RCD), original leads are out. Vibration is a good exercice for comparisson between meters whether they keep the measures stable during that kind of stress or some maybe component snaps out of the PCB :P

 But only takes some water to turn years into seconds,

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 28, 2019, 02:50:17 am
I doubt I would try and power them up during the test and take any readings.  While I can believe that with some of the meters, the adjustment pots could move.  The bigger problem is that some meters, like the 121GW for example, are sensitive to changing magnetic fields.   It's early and I may change my view of this.  I can see doing some sort of before and after test for meters along with pulling it apart for inspection.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 28, 2019, 11:41:19 pm
It will of course be very interesting to see vibration tests on different multimeters and especially Flukes. Because they have removed the "Vibration" and "Shock" heads from the specifications of their multimeters in current revisions. Either they feel no more confident or the requirements have gone more stringent.
From the Fluke 189 manual:
Per MIL-T-PRF 28800 for Class II instruments

Looking at the standard for a Class 2,  for the sinusoidal profile they sweep from 5 - 55Hz and 1.5mm down to 0.5mm.  This may be doable with the home made table.   This document is available for free on-line. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 28, 2019, 11:53:57 pm
Is this what the doctor ordered? Maybe it's not the most recent perhaps..
http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-T/download.php?spec=MIL-T-28800E.030735.pdf (http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-T/download.php?spec=MIL-T-28800E.030735.pdf)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 29, 2019, 12:34:26 am
I was looking at the MIL-PRF-28800F which superseded T.   It's also available on everyspec.com.   See Table 4 attached.

Once the glue sets up for the fixture, I can see how close it will track that profile. 

Link to the full spec if interested
http://everyspec.com/MIL-PRF/MIL-PRF-010000-29999/MIL-PRF-28800F_18207/ (http://everyspec.com/MIL-PRF/MIL-PRF-010000-29999/MIL-PRF-28800F_18207/)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 29, 2019, 05:49:23 pm
Making the round trip from 5 to 55Hz.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 29, 2019, 08:09:38 pm
The frequency follows quite well the table attached in the previous post and displacement results "touché" . It is required to do a pause between frequency ranges while testing?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 29, 2019, 08:58:15 pm
It is required to do a pause between frequency ranges while testing?
Like the transient testing, I am loosely using the standards as a guide.   I provided a link to the standard if you would like to read it.  I suggest section 4.5.5.3.2.   At this time, I plan to run a linear sweep that follows that profile.  Maybe run 3 cycles, up and down, half hour per cycle.   I have no plans to search for resonance.   I'll just let it run and do a before and after functional test and inspection.     I am also thinking to just run it in the one axis, backside down, rather than to look at all three.   It's all up in the air for now until I actually try running a few meters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2019, 03:51:49 pm
Time for a test drive...
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 30, 2019, 04:14:36 pm
Thanks for the info related to the standard and the go to.  Hope the needle of  that Multimeter survives :P
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 30, 2019, 04:21:41 pm
Meanwhile check out the Vbe's supposed aneng basher ,  Mestek DM91A:

https://youtu.be/XojTrnXq_LU

looks better built and uses more common fuses, ,maybe 5x20mm not tiny .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2019, 04:27:59 pm
Thanks for the info related to the standard and the go to.  Hope the needle of  that Multimeter survives :P
It was a fairly inexpensive meter and has a bit of weight to it compared with the pocket meter.   

I'm not sure which axis would be the worse for this particular meter but I am thinking to run them as shown. 

***
Watched his last video.  Would have liked to have seen the PCB removed so we could see the switch contacts.   I suspect it just uses the single PTC and some transistors for the clamp.  Maybe a TVS in there.  I doubt it would do very well in my transient testing.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2019, 05:42:20 pm
On my bike, I have a mechanical pressure gauge which is filled with glycerine to dampen the pulses and vibrations.  Maybe the high end analog meters had some sort of dampeners but this meter doesn't and had a few resonate frequencies.   Poor meter....

https://youtu.be/45LaMWZ9en4
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 30, 2019, 06:36:25 pm
So I take it we could never count on this meter at the Baja 1000?  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 30, 2019, 07:08:23 pm
Wow looks like the needle is having a bad day ilke offroad indeed , What about inside ? Any loosy components?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2019, 07:33:58 pm
Low frequency (no resonance), vertical mount, shot at 1000fps.   Ride em cowboy... 

https://youtu.be/WCIpm8peQSU
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2019, 08:50:09 pm
The mechanical meter did not hold up very well.  Note the adjustment set to both extremes.   One of the batteries had leaked and the vibration caused the solution to spray all over inside the meter.   What a mess... 
Title: Re: Handheld meter electrical robustness testing.
Post by: Towger on March 30, 2019, 09:02:26 pm
Looks like you have discovered a new technique for accelerated battery ageing testing. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 30, 2019, 09:16:05 pm
This reminds me of the first meter I blew up. A Micronta 212. I might buy one off ebay if I see one cheap to see if I can recreate that moment on video. The entire meter front filled up with smoke and the needle fell off after leaving it on the 15V DC range and poking a 300V AC HT secondary on a valve radio transformer.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on March 30, 2019, 09:54:43 pm
This reminds me of the first meter I blew up. A Micronta 212. I might buy one off ebay if I see one cheap to see if I can recreate that moment on video. The entire meter front filled up with smoke and the needle fell off after leaving it on the 15V DC range and poking a 300V AC HT secondary on a valve radio transformer.  :-DD
This could be the victim.. >:D https://www.ebay.co.uk/itm/Radio-Shack-Micronta-22-212-multimeter-works/123706889646 (https://www.ebay.co.uk/itm/Radio-Shack-Micronta-22-212-multimeter-works/123706889646)
Title: Re: Handheld meter electrical robustness testing.
Post by: bd139 on March 30, 2019, 09:57:24 pm
I think I'd probably put 10GBP to it. That is coming up at 28 GBP. Some idiot is selling one here for 49.99 GBP as well which is a joke! It's that bad at 2k/volt it's worth nothing!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 30, 2019, 10:02:55 pm
So the 1.1M was replaced with a short... What could go wrong??!!  lol.   

I remember changing burned resistors on my old analog meter using parts I scavenged from old radios and TV sets.   

(https://metrologu.ru/uploads/monthly_11_2014/post-19004-0-80880400-1417197446.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 30, 2019, 10:50:20 pm
I still have a similar  model called protek a800, analog meter, but it is a pocket meter.

(https://www.eevblog.com/forum/chat/show-your-multimeter!/?action=dlattach;attach=485816)

The battery left inside leaked a bit but didn't take much damaged on the spring contacs.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2019, 02:15:31 pm
A real bandage!   I typically grab the closest tape I have which is normally electrical and some paper towel.    :-DD

Reviews claim the UNI-T is slow to settle.  How slow?  As bad as that Yokogawa? 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 31, 2019, 03:52:11 pm
Got lucky on finding one bandage handy :P Jesus this uni-t 120c had some bad contacts on the battery terminals which would result on bad behaviour. I believe i have posted about freezing the display or turning off by its own  and it was due to this issue.

yeah it is very slow to read capacitors. i don't have  a 150pF cap but can check with a 10uF .
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on March 31, 2019, 04:15:08 pm
Here is a demo of a 10uF capacitor for comparisson.

https://youtu.be/ztD8GVa6tsI

Notice the 9.86nF offset capacitance. do they put a capacitor inside to mitigate the capacitance on the leads or force to rel always?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on March 31, 2019, 11:58:48 pm
Does it ever become stable? Those are some big jumps. 

The leads will add capacitance.  Seen some that will read zero with the leads installed, like that Yokogawa for example.  Just depends on the meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 01, 2019, 03:22:35 am
***
Watched his last video.  Would have liked to have seen the PCB removed so we could see the switch contacts.   I suspect it just uses the single PTC and some transistors for the clamp.  Maybe a TVS in there.  I doubt it would do very well in my transient testing.
Joe, I added the high resolution photos on the video's description, including the rotary switch.

As you imagined, it is an ordinary meter in terms of safety and rotary switch design.

The UT139C that I am still editing is much more promising. I know you tested it up to 5.1kV, which to me is quite impressive (similar to the much more expensive Keysight U1231A)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 01, 2019, 10:35:03 am
Joe, I added the high resolution photos on the video's description, including the rotary switch.

As you imagined, it is an ordinary meter in terms of safety and rotary switch design.

The UT139C that I am still editing is much more promising. I know you tested it up to 5.1kV, which to me is quite impressive (similar to the much more expensive Keysight U1231A)
Thanks for adding them.   Looks like the same old problems we have come to expect.    The UT139C didn't make it as far in the transient tests as the Amprobe AM510, which is a bit strange as both are UNI-T products.  Still, it's more robust than most of their products and AT LEAST it survived that little grill starter that seems to be famous for damaging them.   The difference I see between the 139C and the 510 is that I damaged two 139Cs that could not be repaired.  In the case of the 510, I was able to repair it.   One goes to the recycle, the other lives to run another test. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 01, 2019, 01:00:43 pm
Does it ever become stable? Those are some big jumps. 

The leads will add capacitance.  Seen some that will read zero with the leads installed, like that Yokogawa for example.  Just depends on the meter.

Tested before shooting and it becomes stable at 10.47uF  . I let it sit for some seconds extra on the 10.47uF to reinforce that. It drops when i was to remove the leads. Yeah big capacitance leads.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 01, 2019, 01:50:26 pm
Joe, I added the high resolution photos on the video's description, including the rotary switch.

As you imagined, it is an ordinary meter in terms of safety and rotary switch design.

The UT139C that I am still editing is much more promising. I know you tested it up to 5.1kV, which to me is quite impressive (similar to the much more expensive Keysight U1231A)
Thanks for adding them.   Looks like the same old problems we have come to expect.    The UT139C didn't make it as far in the transient tests as the Amprobe AM510, which is a bit strange as both are UNI-T products.  Still, it's more robust than most of their products and AT LEAST it survived that little grill starter that seems to be famous for damaging them.   The difference I see between the 139C and the 510 is that I damaged two 139Cs that could not be repaired.  In the case of the 510, I was able to repair it.   One goes to the recycle, the other lives to run another test.
Quite interesting. I don't know the AM510, but the UT139C I have is an off-brand and seems to have a much heftier protection when compared to the Surpeer, the Mestek and my chinese-targeted UT-61E (the one with the PCB that looks like suitable for TÜV mark but has gobs of unpopulated MOVs and PTCs).

Despite the lack of input protection, which would never guarantee its status as a CAT III 600V, the Mestek is a very well rounded package IMO (thus the "Aneng killer" title). The NCV is quite useable, the autorange is quite fast (although the continuity is slow), the range distribution is very well rounded and, as malagas mentioned on the comments, the fuses are of a regular size - a much better offer when compared to the Anengs 8008/8009. 

*Please note that, as I mentioned at the end of the video, my opinion may have been biased due to "PTSD" caused by the Surpeer AV4 and its brokeness... :P
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 01, 2019, 03:43:30 pm
The uni-t ut139A which is the basic version of the ut139 line is very similar to amprobe am510 (sorry) functionalities except the true rms. I wounder if it is the 139A has .. needs a fuse inspection
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 01, 2019, 11:43:07 pm
Here are the inside of the meter uni-t ut139A.  it looks the similar to the uni-t 139C:

https://photos.app.goo.gl/aqgaqaD1kn51pPgTA

Fuses are according to the manual, but don't have any UL listeting ,... need to get better view


Edit: Mine has an extra PTC right above the 10A jack and MOV are placed different. The PTC's looks a bit bigger.

video for comparrisson:

https://youtu.be/zFvuigSS2Xk?t=296

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 02, 2019, 02:30:23 am
Malagas, thanks for sharing! It is very similar to the UT139C.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 02, 2019, 08:41:51 pm
i had mixed thoughts ...  was expecting to be the same board as the 139b and 139C less populaded and on the other hand it would be different since it is much more basic compared to its models, not too much cheaper although. Maybe this is a simplifed version and revision is also 2016, maybe more recent than the 139C which looks it is from 2012. :

https://youtu.be/zFvuigSS2Xk?t=292

i see a 190612 number above the ut139 marking. is this a date code?

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 02, 2019, 09:22:08 pm
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Added the Mestek DM91A and the UT139C.

The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 02, 2019, 10:02:20 pm
The backligh on the 139A it is a little dim :( even the ut 50b is brighter but yeah batteries last long on this meter. I didn't measure the cutoff from batteries because as soon as you open they are supposed to come on the compartiment or stay loose inside the meter. Also did an experiment with a NIMH battery which was almost discharged , putted two 390 ohms in pararell with it, leave for two hours and voltage was 1.72V. As soon as i removed from the resistors they instantly increased to 6.7V , which i wasn't aware before you all mentioned.. they do rebound indeed and quickly.

Edit; For now planing measure current draw using fully recharged batteries using better wiring than crocodile clips + thin wires :(
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on April 02, 2019, 10:49:11 pm
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Added the Mestek DM91A and the UT139C.

The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.

Curious how nom. current was measured, as I noticed current draw varies by what measurement setting the multimeters is in, with highest draw usually happening in resistance, diode test or continuity modes.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 03, 2019, 12:27:31 am
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Added the Mestek DM91A and the UT139C.

The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.

Curious how nom. current was measured, as I noticed current draw varies by what measurement setting the multimeters is in, with highest draw usually happening in resistance, diode test or continuity modes.
This is mentioned at the bottom of the table
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 03, 2019, 10:16:10 am
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Added the Mestek DM91A and the UT139C.

The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.

There is another alternative to Mestek DM91A but with less resolution counts ( 6000) , the Uni-t 133A which is a compact true-rms meter witn NCV:

http://www.uni-trend.com/index.php?m=content&c=index&a=show&catid=172&id=192 (http://www.uni-trend.com/index.php?m=content&c=index&a=show&catid=172&id=192)

It costs around 30E on local market with shipping + 2Y waranty and should be cheaper on other market platforrms

Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on April 03, 2019, 11:31:29 am
IMO, non-autoranger's need separate power switches. On the 133A, common functions are 4-6 clicks away from OFF.. FAIL!!
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 03, 2019, 12:56:35 pm
IMO, non-autoranger's need separate power switches. On the 133A, common functions are 4-6 clicks away from OFF.. FAIL!!


That's the model 133B you're refering, the 133A is automatic.

https://www.batronix.com/shop/multimeter/multimeter-ut133b.html (https://www.batronix.com/shop/multimeter/multimeter-ut133b.html)

https://toolboom.com/en/digital-multimeter-uni-t-ut133a/ (https://toolboom.com/en/digital-multimeter-uni-t-ut133a/)

From the official website:

http://www.uni-trend.com/html/product/General_Meters/Digital_Multimeters/UT133_Series/ (http://www.uni-trend.com/html/product/General_Meters/Digital_Multimeters/UT133_Series/)

I believe was my mistake on posting the wrong link , sorry

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 03, 2019, 02:43:41 pm
There is another alternative to Mestek DM91A but with less resolution counts ( 6000) , the Uni-t 133A which is a compact true-rms meter witn NCV:

http://www.uni-trend.com/index.php?m=content&c=index&a=show&catid=172&id=192 (http://www.uni-trend.com/index.php?m=content&c=index&a=show&catid=172&id=192)

It costs around 30E on local market with shipping + 2Y waranty and should be cheaper on other market platforrms
What attracted me to the DM91A and made me call it "Aneng killer" was the price/feature ratio: at a sale on the Banggood site, it was US$16.00 with free shipping, which was less than the Aneng 8008/8009 and much better featured. However, we don't know how this trend will go, as the Anengs were also much less expensive than their current price when they were released (IIRC).

IMO, non-autoranger's need separate power switches. On the 133A, common functions are 4-6 clicks away from OFF.. FAIL!!
That's the model 133B you're refering, the 133A is automatic.
Stupid Uni-T does no favours in completely confusing their product families.

I have a UT136C (http://www.uni-trend.com/html/product/General_Meters/Digital_Multimeters/UT136/UT136C.html) which is a wonderful meter, compact and quite functional. Then, they release a UT136C+ (http://www.uni-trend.com/html/product/General_Meters/Digital_Multimeters/UT136/UT136C+.html) that keeps the same counts, is much larger, conflates the mA with the V/Ω functions and adds a *ugh* transistor hfe tester.

The Uni-T UT-55 had a separate On/Off switch. Quite handy.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 03, 2019, 03:10:27 pm
Yeah in terms of price it is very good the DM91A and thought the ut133A would be in the same price range out of EU market, but it is 23 USD, having similar functions. About confusion just peak the ut204 and the ut204A  . one has true rms and other lot of features, not true rms. I bought the ut204A based on this website instead with has in the parameters true RMS.. opps :

https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut204a (https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut204a)


Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 03, 2019, 05:27:09 pm
Stupid Uni-T does no favours in completely confusing their product families.

Agree.

That, plus the fact that they make some real stinkers and what you get one of their meters often depends on where you bought it.

How is anybody supposed to buy a Uni-T if they know that there's two or three identical-looking variants out there but some don't have any input protection inside?
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 03, 2019, 06:44:33 pm
How is anybody supposed to buy a Uni-T if they know that there's two or three identical-looking variants out there but some don't have any input protection inside?
I agree, but I can tell the wide variance of quality and assembly across the Anengs, Mastechs, etc does not leave much to desire. Well, perhaps you could make the case these brands still actually mount the parts on the board, regardless of the Shenzhen sale of the week.

Despite this, I tend to recommend the UT61E for low voltage electronics as it is still a meter with good enough features for this usage and it sits at a good price range. There is some variability and there are certainly better models and more protected, but transients and sparks at low voltage systems are quite rare - just keep it away from those spark plugs! Another factor is that, at least for my channel, the vast majority of the watchers is cash strapped due to exchange rate and is subjected to severe import taxes.

(I can almost hear Joe's disheartened sigh... )

Joe, just because I can...
I took some photos (https://www.eevblog.com/forum/testgear/review-uni-t-ut136b-tired-of-the-multimeter-snobs-a-very-nice-budget-meter!/msg1143521/#msg1143521) of the UT136C's internals a long while back - however, the rotary switch was missing. Please see attached.

A few details about this meter:
- The grease of the ball bearings of the rotary switch (not seen, as they are in the front enclosure) seem to have seeped a bit into the contacts. This may or may not be dangerous, but at the voltage levels this meter is subjected, I don't see this as a problem.
- There are no vias on the path of the rotary switch blades. That may certainly help with the durability of the contacts
- The range switch feels very good, but I imagine how long the plastics would last in your torture tests.
- There is a single puny PTC at the input, together with clamp transistors and HV resistors. The PTC is in parallel with the V/Ω input.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 03, 2019, 09:25:45 pm
Here the uni-t's that i've seen has mov and ptc populated , eg the 61E, which here is the GS variant, maybe EU requirements . The 139A that i've showned has one extra PTC.  Next time i may open further :P

The uni-t 136C looks like a compact multimeter  , two off positions , simple switch ( not like the 133A here HZ in the mV, bugger ), there is some space that could fit more protection . One of the fuse is glass and other is ceramic on the older picture, which may lead that the original has been tested :P (just kidding) A little bit of flux residue is also present, near the push buttons. Nice digits (Edit)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 04, 2019, 12:52:41 am
The uni-t 136C looks like a compact multimeter  , two off positions , simple switch ( not like the 133A here HZ in the mV, bugger ), there is some space that could fit more protection . One of the fuse is glass and other is ceramic on the older picture, which may lead that the original has been tested :P (just kidding) A little bit of flux residue is also present, near the push buttons. Nice digits (Edit)
IIRC I had blown one of the fuses and grabbed whatever I had on hand.

The UT136C is compact (137 x 72 x 35 mm), mechanically well built and I am still trying to see if there is a strong reason to replace it by the Mestek (too many meters in the collection).

One of the major details that I like about it is that it is "silent": it does not have the annoying beep at every range change.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 04, 2019, 08:20:51 am
Correct if im wrong but Most of the new meters beep on anything , eg rotary switch, buttons, power going off,  they should have an option to mute beep except on continuity . The Mestek it is a good alternative, looses the splitted jack for the mA , but at least NCV has the antena functional and visible, has well other functions.

One more thing about the 133A, they claim a drop of 2 meters :P I was looking for a alternative on the uni-t 50b that i could easly carry on a toolbox
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 04, 2019, 04:25:17 pm
Correct if im wrong but Most of the new meters beep on anything , eg rotary switch, buttons, power going off,  they should have an option to mute beep except on continuity .
Most of the chinese ones, at least. The Brymens and the Flukes and Keysights are quite silent, depending on the model. All of them beep when entering auto power off and the Keysight U1281A/U1282A have two settings for beeps: beep for everything or beep only for continuity/input alert/NCV.

The Mestek it is a good alternative, looses the splitted jack for the mA , but at least NCV has the antena functional and visible, has well other functions.
That is what is so hard about the Mestek: if it had better input protection, it would be a great all around meter for small jobs around the house:
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 04, 2019, 04:35:17 pm
The Mestek it is a good alternative, looses the splitted jack for the mA , but at least NCV has the antena functional and visible, has well other functions.
That is what is so hard about the Mestek: if it had better input protection, it would be a great all around meter for small jobs around the house:
  • The NCV is really good, with the proper sensitivity to identify which side of the romex cable is carrying the live
  • The capacitance is reasonable for HVAC systems
  • The flashlight saved me from a few bad scenarios
  • The 1.5V and 9V battery testers are quite handy

Downsides:
* Basic accuracy isn't very good (0.7% DC voltage)
* It's a bit slow at everything (eg. continuity tester is awful,  it takes ~3s to measure a 100 Ohm resistor)
* If you're not interested in AC mains the the first two stops on the selector will annoy you every time you have to click past them.
* It's not small
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 04, 2019, 05:53:55 pm
The Mestek it is a good alternative, looses the splitted jack for the mA , but at least NCV has the antena functional and visible, has well other functions.
That is what is so hard about the Mestek: if it had better input protection, it would be a great all around meter for small jobs around the house:
  • The NCV is really good, with the proper sensitivity to identify which side of the romex cable is carrying the live
  • The capacitance is reasonable for HVAC systems
  • The flashlight saved me from a few bad scenarios
  • The 1.5V and 9V battery testers are quite handy

Downsides:
* Basic accuracy isn't very good (0.7% DC voltage)
* It's a bit slow at everything (eg. continuity tester is awful,  it takes ~3s to measure a 100 Ohm resistor)
* If you're not interested in AC mains the the first two stops on the selector will annoy you every time you have to click past them.
* It's not small
Fungus, using the meter I can tell it is slow only on continuity - the rest is quite on par with meters of the same class. 
The first two stops are indeed annoying. I have no idea why they chose this arrangement.
The meter is marginally larger than the AN8008/8009/UT136C and thicker (149 x 70 x 47 mm). Remove the rubber boot and you get 149 x 66 x 35 mm - only 15mm longer than the Anengs and the UT136C, but with a stand.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 04, 2019, 07:40:34 pm
For the intent of replacing an compact meter such as a aneng 800x , uni-t 136C, the mestek is another alternative . The arrangement of this meter is maybe due to be target for electrical purposes as mestek sells various products in this range, like socket testers, NCV's , clamp meters ( notice the first position is in LoZ )

http://www.mestek-tools.com/en/productdetail.aspx?detailid=56 (http://www.mestek-tools.com/en/productdetail.aspx?detailid=56)

 As for the beeping the U1282A if not turned off its a bit anoying  at work :P The U1252A/B are definitly more silent and quite good to work. Brymen doesn't beep as much but has a loud beep :P Fluke its tolerable

Here is another option:

https://www.tacklifetools.com/product/product/index/id/177 (https://www.tacklifetools.com/product/product/index/id/177)

But watch out for the description :P 4 x 15V AAA batteries
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 04, 2019, 09:34:05 pm
As for the beeping the U1282A if not turned off its a bit anoying  at work :P The U1252A/B are definitly more silent and quite good to work. Brymen doesn't beep as much but has a loud beep :P Fluke its tolerable
My U1282A is beeps hysterically when the switch range goes to the µA/mA/A ranges, with or without probes connected anywhere on the meter. Does yours do that as well? It is quite an annoying behaviour.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 04, 2019, 09:59:16 pm
Beeps  5 times fast when probes are not properly connected, eg leave probles in V when rotate to A / mA The Keysight / Agilents are on the company that currently work. Good tools for longevity since this are the ones that stills get's OK for calibration routine :P
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on April 05, 2019, 03:00:14 am
Yes, the U1282A is pretty vocal in current modes with no probes connected in either beep mode. I was quite relieved when I found the option for continuity/NCV-only beep mode. The probe warning is nothing in comparison to the default beep mode for annoyance.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 07, 2019, 04:07:25 pm
The Keysight U1282A is also water resitant .. ip67 , i would like to test this in a swimming pool,  :-DD maybe every 100m to check if water as getting inside but dave has done a good job on giving a bad time to it.

Here is another alternative for the aneng  800x, the aneng V01B ... bah loses uA, temperature and 1 splitted jack.  try the H01

For the 55000 counts meter here's a maybe new comer Victor 189B (Edit not new and expensive compared to another thread :S ):

- Multimeter Accuracy 0.025% 1ms Peak Sampling True RMS TC RTD Log USB

https://ebay.us/to4qhG

And local meter... cat iv :P Xindar DPLAB250 :

https://xindar.com/producto/multimetro-digital-true-rms-profissional-industrial-dplab250/?lang=pt-pt




Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 07, 2019, 07:53:33 pm
The Xindar looks very similar to the Mastech MS8250 series (MS8250D, perhaps?). They came with this new "transformers" format somewhat recently.

http://mastech-group.com/products.php?cate=93&page=2 (http://mastech-group.com/products.php?cate=93&page=2)

Credit: the "transformers" idea came from another thread:
I'm pretty sure the design is modeled on the "Transformers" movie franchise.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 07, 2019, 08:31:29 pm
Yep very similar and maybe an overpriced clone or it's the EU version.    The other meters from the same brand looks like peakmeter's  and "transformer" stylish, spaceship, like the Aneng V01A :P

Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on April 08, 2019, 12:05:43 am
Found a rather comical DMM testing guy (https://youtu.be/V-vBcCKk2NI?t=418) on YT this evening.. he says he's got a bunch of items on order for new reviews, so I subscribed for the variety. I was also surprised the 10,000 count Mestek DM91a (https://www.ebay.com/itm/MESTEK-DM91A-Handheld-LCD-Digital-Multimeter-9999-Counts-Manual-Ranging-Tool/253970570733) can sell for just $16.51 on flea-bay.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 08, 2019, 01:03:37 am
Found a rather comical DMM testing guy (https://youtu.be/V-vBcCKk2NI?t=418) on YT this evening.. he says he's got a bunch of items on order for new reviews, so I subscribed for the variety. I was also surprised the 10,000 count Mestek DM91a (https://www.ebay.com/itm/MESTEK-DM91A-Handheld-LCD-Digital-Multimeter-9999-Counts-Manual-Ranging-Tool/253970570733) can sell for just $16.51 on flea-bay.

You old age is showing.   I remember that guy with his 10,000s of thousands of annual switch cycles.  :-DD :-DD    I couldn't sit through the videos he made on the Keysight meter to debunk my test results.  I think Fungus may have watched them. 
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/2175/ (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/2175/)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on April 08, 2019, 01:20:56 am
I said he was comical.. ??? but obviously not at your level. IMO I like it when someone else (not me) shells-out coin for these iffy DMM's to give me PCB shots so I can make my own judgments. Now an old pro wouldn't be jealous, would you? :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 08, 2019, 01:54:48 am
I said he was comical.. ??? but obviously not at your level. IMO I like it when someone else (not me) shells-out coin for these iffy DMM's to give me PCB shots so I can make my own judgments. Now an old pro wouldn't be jealous, would you? :-DD
I think he said he was in IT and they used that meter for service work, some story like that.   

I watched one of his videos.  He had a bunch of sound effects, blabbed on with no substance and then gave the meter 5 stars.   I wasn't finding any entertainment and certainly no data.  That's why I just couldn't sit through another.   

If you like his work and feel this is the proper place to advertise his channel, that's fine.  Personally, I don't see the correlation.   Perhaps it's more about you being still upset after I called you out about your comments and you having the admins waste their time erasing it.   Or perhaps you are indirectly suggesting that I stop making hardcore reviews on these meters.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on April 08, 2019, 03:21:22 am
Correlation: He spends $$, we see the guts in what we shouldn't buy in the first place. I don't recall anything about 10,000 switch cycles.. if I saw his comments prior, I obviously didn't think it was worth remembering.. some things aren't ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 08, 2019, 12:12:39 pm
Correlation: He spends $$, we see the guts in what we shouldn't buy in the first place. I don't recall anything about 10,000 switch cycles.. if I saw his comments prior, I obviously didn't think it was worth remembering.. some things aren't ;)

If spending money and taking meters apart is all you are after, there are a lot of channels out there you may find interesting.   I was attempting to bring something more to the table but maybe these hard core tests really are meaningless to the average viewer.   Back when I took a poll,  a fairly high number of votes were to stop.  It could be there is even less interest now.       

If you spend the time to read that couple of pages I linked, he wouldn't even take that Keysight meter apart as part of his big debunk video that he had made such a fuss over.  He did however talk about how many cycles they put on their meters.  You like his videos, I suggest you actually watch them.   So again, why are you advertising for him in this thread?   
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on April 08, 2019, 02:33:05 pm
If I said his channel was comical, I fail to see that as promotion.. but I'll not exercise this kind of liberty on the thread further. As for you saying "It could be there is even less interest now" I respectfully have to disagree. Your work has been monumental and has made some mfg's (of any worth) sit-up and take notice. Keep going Joe, even though we periodically "give each other the rub" I am for and not against your efforts. FWIW, Joseph may recall the effort's and encouragement's we gave to a YT friend in the Ukraine (I don't remember the channel name), but when he was discouraged, we told him the same thing.. keep going! It may sound rather groupie-ish to say it, but we are some of your biggest fans :-+  Cheers!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2019, 02:12:57 am
There was a time in my life when I found funny sounds entertaining.  Maybe till the age of two. 

It really doesn't require a lot of intelligence to spend money on meters.  Making videos is a struggle and there will be countless people doing a much better job.   I really have little interest in that aspect.  What you may not find very often is people who have the ability to take a cheap 35$ clamp meter and increase it's bandwidth from a few KHz to a 100KHz.   Solving problems like this is really what I enjoy doing.         

I don't sell products, take donations or get paid by any companies for the data I show.   As you said, it's my money that pays for it along with my time.  I make it all free to the public.  It's a total loss on my part.   The only thing I gain from it is seeing for myself how these various meters hold up to one another.   I suggest you consider this when using the thread.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2019, 03:41:40 am
Here you go!!  I have started a new poll where you have a chance to voice your opinion about continuing these tests.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 09, 2019, 09:25:37 am
Here you go!!  I have started a new poll where you have a chance to voice your opinion about continuing these tests.

Zap 'em! Grind 'em! Lick 'em to death!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2019, 12:19:50 pm
Here you go!!  I have started a new poll where you have a chance to voice your opinion about continuing these tests.

Zap 'em! Grind 'em! Lick 'em to death!
You may enjoy watching the next video.  You're big on the drop and vibration tests.  I plan to use that poor man's vibration table as part of my testing.   I'm sure those speakers were not designed for what I am doing with them....
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 09, 2019, 09:08:02 pm
Not all meters were completly destroyed but yeah  damaged by the tests   and the very good part (Edit terrible english sorry ) was they where able to be repaired which all bonds to all work one here.  There's also the third option. Take to an ESD or IEC certification lab for testing :P 
Title: Re: Handheld meter electrical robustness testing.
Post by: sylvandb on April 09, 2019, 10:16:30 pm
I plan to use that poor man's vibration table as part of my testing.   I'm sure those speakers were not designed for what I am doing with them....

Ever heard of buttkicker transducers? Might be just the ticket if those speakers aren't sufficient...  thebuttkicker.com
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2019, 10:39:20 pm
Not all meters were completly destroyed but yeah  damaged by the tests   and the very good part (Edit terrible english sorry ) was they where able to be repaired which all bonds to all work one here.  There's also the third option. Take to an ESD or IEC certification lab for testing :P
A very low percentage of the meters I have looked at were able to be repaired.  Most go to the recycle bins.  That's one of the main differences I see with these low end meters, they are disposable.  I may damage the higher end meters but they have normally paid enough attention to the details to where the controller IC is not damaged and I have been able to repair them.   Maybe 30%. 

To rent time at a lab and have a product certified I would imagine is in the order of $20,000 or so USD.   I really don't see that as being an option.  Even if we didn't certify them, the rental costs would far exceed what I would be willing to spend.   The we have the problem that I am not really interested in seeing the meters pass their safety standards or not.  A lab like this will have generators specifically for running the IEC standards which is not at all what I have been showing.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 09, 2019, 10:46:13 pm
I plan to use that poor man's vibration table as part of my testing.   I'm sure those speakers were not designed for what I am doing with them....

Ever heard of buttkicker transducers? Might be just the ticket if those speakers aren't sufficient...  thebuttkicker.com

LOL!!! I have and looked at them.  We were having a big laugh a few weeks ago while watching some of the kids with their 5 alternators driving their sound systems.   This is when we saw the buttkicker.    A friend of mine dropped off a large bass driver that I am considering.   It has a built-in amplifier but it appears it's not DC coupled.    When I eventually release the next video, people will get a better idea about the tests and maybe provide some useful feedback.    It's maybe another week out.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 10, 2019, 09:35:03 am

To rent time at a lab and have a product certified I would imagine is in the order of $20,000 or so USD.   I really don't see that as being an option.  Even if we didn't certify them, the rental costs would far exceed what I would be willing to spend.   The we have the problem that I am not really interested in seeing the meters pass their safety standards or not.  A lab like this will have generators specifically for running the IEC standards which is not at all what I have been showing.

Opps i should clarify  that the option was intended to the viewers , not for you to check, since you mentioned something about this matter in one or more the videos as a sugestion.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 10, 2019, 11:34:29 am

To rent time at a lab and have a product certified I would imagine is in the order of $20,000 or so USD.   I really don't see that as being an option.  Even if we didn't certify them, the rental costs would far exceed what I would be willing to spend.   The we have the problem that I am not really interested in seeing the meters pass their safety standards or not.  A lab like this will have generators specifically for running the IEC standards which is not at all what I have been showing.

Opps i should clarify  that the option was intended to the viewers , not for you to check, since you mentioned something about this matter in one or more the videos as a sugestion.
This is normally preceded by a viewers comment about how I have shown how safe or unsafe a meter is,  which obviously I don't. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 12, 2019, 07:44:04 pm
And for vibration test on "disks" is IDE or SATA better:?


https://ebay.us/HywXET
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 12, 2019, 10:42:28 pm
You like the meters that share the current with the voltage? 
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on April 12, 2019, 10:49:11 pm
You like the meters that share the current with the voltage?
I don't but $20 is small change. It's almost a pocket meter, IMO.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 12, 2019, 10:55:39 pm
I have looked at a lot of low cost meters.  Nothing I have seen outside of the Fluke 101 has held up very well.  I doubt this meter, based on your picture would do very well in my tests unless there is something below we are not seeing. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 12, 2019, 11:08:39 pm
well they don't last very long when memory gets blanked :P "There goes the fuse." The shape of that meter looks like a slim HDD ,. , not a roboto style .and fragile , overpriced.

Point is that meters specially those cheap with lots of trimming pots will have a bad day in the vibration tests. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 12:00:07 am
I best not shake my Mastech meter then.  I think it has more pots than any of my working handheld meters.   
Title: Re: Handheld meter electrical robustness testing.
Post by: mqsaharan on April 13, 2019, 09:44:04 am
I best not shake my Mastech meter then.  I think it has more pots than any of my working handheld meters.

Please do include at least one multimeter of your choice with pots for calibration.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 13, 2019, 10:09:54 am
I best not shake my Mastech meter then.  I think it has more pots than any of my working handheld meters.

Please do include at least one multimeter of your choice with pots for calibration.

In my amateur imagination there's a huge difference in vibration resistance between single turn and multi-turn (worm-gear) pots, it would be good to test that.

Do any handheld multimeters use these for adjustment?

(http://www.robotroom.com/Parts/Inside-multiturn-trimpot-with-worm-drive.jpg) (http://www.robotroom.com/Trimpots-2.html)

Title: Re: Handheld meter electrical robustness testing.
Post by: stj on April 13, 2019, 02:13:42 pm
UT-61E uses those - i suspect they shift if you hit them hard enough - there is lash when you change direction ajusting them.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 13, 2019, 02:21:21 pm
Does the masteech has many pots as this ut204A? It looks all condensed for fitting the damn 9V battery.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=603298)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 02:39:29 pm
The UNI-T UT61E I have used a 10 turn pot to trim the reference.   I had replaced it with a part from Bourns when trying to improve it's temperature drift.    Another meter that uses one is the Extech EX540 / CEM DT9939

I have seen several posts mentioning the problems with the UT61E loosing accuracy over time and some assume it has to do with that 10T pot.   I mentioned to you at one point about buying some pots and doing your own drop test.   I think something like this may still be a better approach.   Basically mounting various pots to a board, setting them to their center, measuring them.  Then drop them or run a sweep. 

I have a few meters that have not gone to the recycle yet that I could strip the pots from to run a test like this. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 02:49:43 pm
Does the masteech has many pots as this ut204A?
It appears so.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on April 13, 2019, 03:41:06 pm
What I saw on UT70C is that trimpot has too much of the adjustment range. Replacing it with combination of fixed resistors and much smaller trimpot would make much more stable in that regard.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 04:07:16 pm
What I saw on UT70C is that trimpot has too much of the adjustment range. Replacing it with combination of fixed resistors and much smaller trimpot would make much more stable in that regard.
I have seen others post that as well.   The two UT61E's I looked at, came with 2K trimmers.  When I measured them, they were both set below 1K.   So I replaced mine with a 1K.   I was only looking to improve the temperature drift, which this change did nothing to help.   

I still check this meter from time to time and have not seen any sort of trend with it. 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 08:32:09 pm
I have a few meters that have not gone to the recycle yet that I could strip the pots from to run a test like this.

Most of the meters I look at now do not have trimmers.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on April 13, 2019, 08:47:12 pm
Most of the meters I look at now do not have trimmers.
Not for calibration, but they still might have frequency response trim in AC path..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 09:06:28 pm
True.  The caps on that test board are for that.   I would imagine there are very few people who bounce their meters around that get too concerned with their -3dB point.  :-DD     I think the Fluke 17B+ had a single trimmer for the temperature. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 13, 2019, 09:48:31 pm
Indeed it as a trim pot the 17B+ :P Maybe a later add-on on this line of meter .

https://youtu.be/DvC5woDYGd4?t=590
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 13, 2019, 10:35:26 pm
Anymore even the free HF meter no longer has a trimmer.   

I thought I had saved the parts from my 61E mods, but no luck.  Maybe after I release the next video (won't be much longer), Fungus can chime in if he thinks its a hash enough vibration test or not.   There's no weight to them and they seemed tight when I went to set them to their center positions.  Hard to believe they will move much unless I strike them with a hammer...
Title: Re: Handheld meter electrical robustness testing.
Post by: stj on April 14, 2019, 11:16:48 am
a real world test would be dropping them down some stairs, / a liftshaft(only 1-2floors)
or somehow fixing it to an engineblock and running it for a day.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 14, 2019, 12:16:07 pm
Dropping it from the roof onto concrete would similar to dropping a feather and watching it float.    :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 14, 2019, 02:26:04 pm
I may eat my hat later, but I suspect the smaller the trimmer, the less susceptible to a constant vibration it would be.

Obviously, if the equipment is subjected to a direct multi-G impact (from a fall), then I suspect the most fragile parts would be more susceptible to damage.

Oh, well... Let's wait for the video.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 14, 2019, 04:09:05 pm
Another test is pack badly a meter for shipping or let in the back of a jeep , doing off road , with MEMS and data logger inside. Not quite exact science...
The video  will reveal a in a controller manner.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 14, 2019, 05:14:15 pm
Even if we had a test car and paved test track, I doubt I could do a very good job repeating a test like this.    With the table, it's a closed loop system.   A step in the right direction but still, not exact science as you put it.   

FYI, the test board shown weight 18.97g.  The little Brymen pocket meter weighs 78g.   My Fluke 189, 545g.   

The trimmer package on the test board seems to be the most commonly used from the meters I have looked at. The Mastech MS8264 appears to use the same package but the MS8211 used a different part.     The Mastech I still have, MS8229, uses some larger plastic trimmers but it's a much older meter. 

The trimmers appear only on the low end meters and the most common are the ones show, so maybe we can learn something from it.  Like any rabbit hole, its just how deep we decide to go.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 14, 2019, 05:49:06 pm
A much better aproach and system than the car test dummy . Different styles of pot's, damages and... wires ;P  mastech MS8229 looks modular to the top board which looks the enviroment sensors.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 14, 2019, 05:57:27 pm
Yes, the top board has the sensors on it.   This meter has a lot of features you won't normally see.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 14, 2019, 08:25:28 pm
At local market it currently selled the MS8229 which has luxometer, soundmeter, termometer , humidity. What about measuring sound  dB with MS8229 off the vibration plate?

Here is the meter at local store:

https://www.castroelectronica.pt/product/multimetro-digital-5-em-1-luxsonotermohigrometro--mastech-1 (https://www.castroelectronica.pt/product/multimetro-digital-5-em-1-luxsonotermohigrometro--mastech-1)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 14, 2019, 08:36:58 pm
At local market it currently selled the MS8229 which has luxometer, soundmeter, termometer , humidity. What about measuring sound  dB with MS8229 off the vibration plate?
Sells for about $50 USD.  I am not sure what you are asking.  Do you want to know the sound level of the plate?   If so, do you just want the peak dBm and what frequency?  Keep in mind that I have no way to know if the the meter is in calibration.   It would be some relative number.  Not sure how it would relate to anything.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 14, 2019, 10:46:16 pm
Was asking peak volume on specific frequency applied to vibration and if we could correlate the applied vibration using sound meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 15, 2019, 12:56:16 am
Ok.  I think it would be VERY complex to come up with a set of equations to tie the sound level of this table to the vibration levels of something else.  At best, it seems like the start of your PHD.   The speakers, even though they have a table attached to them are still speakers and do a fairly good job making sound.  A car engine for example, not so much.   

I am rendering the next video.  This ones been in the works for several months.   Hope to release it in the next day.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 15, 2019, 08:39:45 am
Thanks for clarifying , no PhD at all just an idea for another project. Hope for the good video :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 15, 2019, 04:01:02 pm
Enjoy

https://youtu.be/z42eqXfA4eI
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 15, 2019, 06:17:25 pm
Joe, interesting tests, but when you mentioned "Mother Nature" I thought you would also go the other side of 0°C. I was thinking the chances of survivability of a DMM on a cold weather are much higher than on sunny hot weather. The obvious first casualty would be the LCD, thus it would have to be protected from direct sunlight. I imagine the second casualty would be the plastic enclosure, which depending on the material it will be affected by the UV. 

Summer is coming and maybe I get one of these and try to do a test here. With the temperatures we can reach here in Texas (sometimes we get +40°C in the shade), I suspect the little Brymen/Amprobe would not fare as well. I could also leave it in the attic, where temps easily reach +45°C (maybe more).

Oh well... thanks again for the video and keep on burning them!
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 15, 2019, 08:09:28 pm
As commented this was cryogenics for multimeters :P Currently have a TI 89 which had some corrusion, got cleaned with flux, new solder joints, powered up with 4xAAA no backup working, oven and 1 week on inside the car on summer for reflow :P, i believe 3 years ago. It is still working except for the backup battery. IMother nature took care of if. :P

About the vibration tests, planing to do a simple stir starter using a microphone instead of mems to check frequency peak only, eg using audacity or sox,

About battery testing :P here's a hint as attachment for creating dummy's
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 16, 2019, 02:22:43 am
Joe, interesting tests, but when you mentioned "Mother Nature" I thought you would also go the other side of 0°C. I was thinking the chances of survivability of a DMM on a cold weather are much higher than on sunny hot weather. The obvious first casualty would be the LCD, thus it would have to be protected from direct sunlight. I imagine the second casualty would be the plastic enclosure, which depending on the material it will be affected by the UV. 

Summer is coming and maybe I get one of these and try to do a test here. With the temperatures we can reach here in Texas (sometimes we get +40°C in the shade), I suspect the little Brymen/Amprobe would not fare as well. I could also leave it in the attic, where temps easily reach +45°C (maybe more).

Oh well... thanks again for the video and keep on burning them!

It doesn't get very warm here during the Fall to Spring months.    Having it sit in the car during the mid Winter months, the meter goes from a very cold temp to toasty and back to cold in a short time.   

My cars and bikes use LCDs in their instrument clusters.   The bikes have a back cluster.  The cars will sit in the sun with their windows up.  I have not seen an LCD fail in these conditions.

It would be interesting to have someone else try and replicate True's findings.   The claim was five of these all failing the same?   I would have expected that after everything I have exposed this one to that it would have been damaged.   True and his friend must have some magic combination.           
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 16, 2019, 02:45:43 am
Joe, interesting tests, but when you mentioned "Mother Nature" I thought you would also go the other side of 0°C. I was thinking the chances of survivability of a DMM on a cold weather are much higher than on sunny hot weather. The obvious first casualty would be the LCD, thus it would have to be protected from direct sunlight. I imagine the second casualty would be the plastic enclosure, which depending on the material it will be affected by the UV. 

Summer is coming and maybe I get one of these and try to do a test here. With the temperatures we can reach here in Texas (sometimes we get +40°C in the shade), I suspect the little Brymen/Amprobe would not fare as well. I could also leave it in the attic, where temps easily reach +45°C (maybe more).

Oh well... thanks again for the video and keep on burning them!

It doesn't get very warm here during the Fall to Spring months.    Having it sit in the car during the mid Winter months, the meter goes from a very cold temp to toasty and back to cold in a short time.
Yes, the wide variance in temperature would have a very extreme effect as well. However, I have no idea what would be the survivability rate of a meter inside a car during summer - in the worst days it can reach 55°C.

My cars and bikes use LCDs in their instrument clusters.   The bikes have a back cluster.  The cars will sit in the sun with their windows up.  I have not seen an LCD fail in these conditions.
Yes, I haven't either in my car and its LCD clusters, but none of them are in direct sunlight exposure. Leaving my ancient Fluke 27 or any other more modern meter facing the sun starts with a rainbow effect and culminating with a complete blackout.

I don't recall any permanent damage to the meters, but maybe a test like that would be one more datapoint between the various budget brands. If I am feeling brave, I may try that as well, but I don't have the same range of meters than you (I tend to resell the meters I evaluate, so I can keep on going with this hobby).

It would be interesting to have someone else try and replicate True's findings.   The claim was five of these all failing the same?   I would have expected that after everything I have exposed this one to that it would have been damaged.   True and his friend must have some magic combination.           
I kinda lost interest after he/she stopped responding. To our benefit, you kept pushing and came with a very interesting series of tests after that.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 16, 2019, 03:20:49 am
The bike's clusters can easily be in direct sun light.  I have a solar powered LCD watch that must be pushing 20 years old now that is left in the sun to charge.  I have run into problems with the displays washing out over wide temperatures.  You can see these effects in my temperature tests.  The only one I have seen damaged was on a used Fluke 97 I bought that required a new polarizer lens.

Its too bad True left.  I assume they were trolling just based on where they posted but you never know.  Personally I would have bought a different meter if one failed. There's no way I would buy three more.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 16, 2019, 09:43:00 am
As commented this was cryogenics for multimeters :P Currently have a TI 89 which had some corrusion, got cleaned with flux, new solder joints, powered up with 4xAAA no backup working, oven and 1 week on inside the car on summer for reflow :P, i believe 3 years ago. It is still working except for the backup battery. IMother nature took care of if. :P

About the vibration tests, planing to do a simple stir starter using a microphone instead of mems to check frequency peak only, eg using audacity or sox,

About battery testing :P here's a hint as attachment for creating dummy's
Sorry.  I don't understand your vibration sound test.  I assume you are planning to make a stirring system but I am guessing where I am used to seeing a rotating part, you plan to do something that will viberate.  I am not sure how MEMS technology fits in but guessing you plan to use the microphone to measure the sound level.   You will need to know displacement at that frequency.   Then somehow you will use this to compare against some other vibration system?   

The picture appears like you are attempting to mold some pawn chess pieces.  Are you suggesting I make a mold to produce some dummy batteries?   If so, it may be easier for me to turn a few parts on a lathe.


Hi about the vibration sound test i need be able to control the vibration strength and adjust the bass pulses in order to stir, but no spill the liquid, depending on its viscosity the microfone would be a feedback to check if frequency is at least stable and repeatable, it doesn't need to be much accurate but repeatble. Thought i could use mic to get a rough measure of the displacement  but it is farfetch maybe...

About the mold it's a thing about a post when i told was gonna perform some battery measurements on multimeters and publish the results. Tried first atempt with aligator clips but they pose lots of losses. , so decided to use a mold  recreating shapes made of hot glue (chess pieces), to plan in the future make batery with glued contacts and proper wire to mate the DMM.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 16, 2019, 11:42:49 am
About the mold it's a thing about a post when i told was gonna perform some battery measurements on multimeters and publish the results. Tried first atempt with aligator clips but they pose lots of losses. , so decided to use a mold  recreating shapes made of hot glue (chess pieces), to plan in the future make batery with glued contacts and proper wire to mate the DMM.

Your DMMs must draw a lot of current for you to measure lots of drop with an alligator clip.   

What does your liquid shaker system have to do with meter testing? 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 16, 2019, 11:50:56 am
About the mold it's a thing about a post when i told was gonna perform some battery measurements on multimeters and publish the results. Tried first atempt with aligator clips but they pose lots of losses. , so decided to use a mold  recreating shapes made of hot glue (chess pieces), to plan in the future make batery with glued contacts and proper wire to mate the DMM.

Your DMMs must draw a lot of current for you to measure lots of drop with an alligator clip.   


What does your liquid shaker system have to do with meter testing?

The DMM used in question was the ut204A clamp meter which draws 7.91mA  in clamp meter mode  DC current, and a voltage drop from 9.25V to 9.15V is presentented between battery and terminals using that piece of crap aligator clips , very thin wires :(

As said was reusing the idea of a speaker for another project , forgot to mention that is not directly related to meters. :P
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 16, 2019, 12:11:35 pm
About the mold it's a thing about a post when i told was gonna perform some battery measurements on multimeters and publish the results. Tried first atempt with aligator clips but they pose lots of losses. , so decided to use a mold  recreating shapes made of hot glue (chess pieces), to plan in the future make batery with glued contacts and proper wire to mate the DMM.

Your DMMs must draw a lot of current for you to measure lots of drop with an alligator clip.   


What does your liquid shaker system have to do with meter testing?

The DMM used in question was the ut204A clamp meter which draws 7.91mA  in clamp meter mode  DC current, and a voltage drop from 9.25V to 9.15V is presentented between battery and terminals using that piece of crap aligator clips , very thin wires :(

As said was reusing the idea of a speaker for another project , forgot to mention that is not directly related to meters. :P

So, 9.25-9.15 or 100mV drop / 7.91mA or 12.6 ohms!  Again, that alone should strike you as odd.  Just an FYI, I have a test running right now using a few feet or wire and alligator clips.  At 700mA, it is dropping 11mV across one test lead, that includes the alligator clip to the post of the fixture.  0.015 ohms?   

This thread has always morphed from the beginning.   From pictures of cats to now chess pieces.   :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 16, 2019, 01:17:59 pm
I had a post of a paper with the measuring in this thread in native language .... Now the chess pieces is a part of learning process for creating the shape of the batteries. The material used as mold that i forgot to mention was modeling clay and can be reactivated with water even very hardened, but this process of reactivation take almost one day and using a stir starter would speed up the process.

Post with measured values of current on various modes of ut204A:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2177561/#msg2177561 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2177561/#msg2177561)

Yeah should figure out once the first reading of current but kept doing the test to check at least an expected value on other modes.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on April 16, 2019, 03:59:31 pm
a voltage drop from 9.25V to 9.15V is presentented between battery and terminals using that piece of crap aligator clips , very thin wires :(

That seems easy to fix - get some thicker wire, solder it to the clips.  :-//

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 16, 2019, 04:15:55 pm
Don't trust the alligator clips even.... cheap crap are good for the recycle bin. Have spare contacts or crimping terminals , thicker wire, hot glue and banana connectors, not aligator :( , and the mold and shape off battery to press fit the contacts comes in place.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 16, 2019, 08:46:05 pm
llooll i just came back with the aligator clips and the aligator fell out ..... the wire looks like it has some corrusion ... yeahhh sorry folks ..  :palm:

also the plastic around the aligator has hardened to the point it has no flex. garbage.... Edit ( dissect the broken one .. busted)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on April 17, 2019, 12:44:07 am
Malagas, the super cheap alligator clip sets similar to the one on your photo are very low quality.  I have some others that have been resisting quite well the test of time.

It is entirely related to the quality of yhr plastics and, obviously, the assembly. Most of them are just badly crimped - I usually solder them after the purchase.
Title: Re: Handheld meter electrical robustness testing.
Post by: Housedad on April 17, 2019, 12:52:49 am
Sorry. posted in wrong thread
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 17, 2019, 08:17:18 am
Malagas, the super cheap alligator clip sets similar to the one on your photo are very low quality.  I have some others that have been resisting quite well the test of time.

It is entirely related to the quality of yhr plastics and, obviously, the assembly. Most of them are just badly crimped - I usually solder them after the purchase.

Good advice, maybe plan to order some aligator clips and other stuff and use proper wire later.  Plan to go with the dummy cells , since it is quite easy to replicate. Sorry if i posted things out of the subject, but it was an example on how was going to perform the tests.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on April 20, 2019, 09:58:40 pm
This reminds me of the first meter I blew up. A Micronta 212. I might buy one off ebay if I see one cheap to see if I can recreate that moment on video. The entire meter front filled up with smoke and the needle fell off after leaving it on the 15V DC range and poking a 300V AC HT secondary on a valve radio transformer.  :-DD

BD139, not sure when your birthday is but consider this my gift to you.   :-DD

https://youtu.be/YF0TDNjy8tA

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 20, 2019, 10:36:07 pm
It got an "LED" on the output jack as said :P The needle was dancing to the mains AC  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: Kean on April 21, 2019, 12:52:20 am
The dancing needle was the icing on the cake so to speak  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 24, 2019, 11:46:40 pm
Hello news from photoninduction:

https://www.youtube.com/user/Photonvids/community (https://www.youtube.com/user/Photonvids/community)

"New series coming soon boys!! Update well over due and will be posted soon. Its looking good at last:)"

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 26, 2019, 04:02:27 pm
Here is the first dummy 9V battery using modeling clay, as mentioned on chess pieces as tryout tests. it didnn't got perfect , needed to cut bottom side to fit and add some sponge to held battery. The contacts are miniaturized faston, crimped, bent at 90º and although they are not aligned they make good contact on the battery contacts of the ut204A as example


it will be the model for testing current draw using multimeters and cut-out using diy power supply based on rd dps5005

- diy power supply post :

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2366265/#msg2366265 (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2366265/#msg2366265)

next follows using 9V holder with same 0.75mm wire, mating crimpings and banana plugs. This way it can be done another dummy battery eg AAA and plug directly to wiring
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on April 26, 2019, 09:18:13 pm
And of course a meter to you're consideration... an aneng M11 with no roboto style, with self healing component ,  maybe for current protection , some sort of resetable fuse + sw


https://www.eevblog.com/forum/testgear/weird-new-aneng-multimeters-hybrid-design/msg2370522/#msg2370522 (https://www.eevblog.com/forum/testgear/weird-new-aneng-multimeters-hybrid-design/msg2370522/#msg2370522)

Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 14, 2019, 02:14:13 am
To celebrate Andy's return, finally a video that has nothing to do with handheld multimeters. 


For the coax, could you have used something like Time Domain Reflectometry rather than a loop?  On the fibre, is there something similar to TDR you could have used?
 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 18, 2019, 12:00:16 am
Nice Setup's for the measurement from the coax to fiiber optics implementation, A plan, a test pilot and final setup :D
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 18, 2019, 07:10:31 pm
is that me going insane again or did i see at 00:30 a HP band on the monitor? it is an external monitor to the lecroy 8500A or ethernet / USB connection on Desktop PC?   By the way this model is easy to use as its predecessors?
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 18, 2019, 07:31:28 pm
is that me going insane again or did i see at 00:30 a HP band on the monitor? it is an external monitor to the lecroy 8500A or ethernet / USB connection on Desktop PC?   By the way this model is easy to use as its predecessors?

VGA output lloolll   The external monitor looks to have some glare , image is very crisp . i was not understanding at first time why the vga connection needed and where it was being outputed... directly or PC. Sorry

You got the same result with same setup, different scope so it is in spec twice. More Edit .... This way you also get trusty coax , fiber optics cables :P
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 18, 2019, 11:59:31 pm
yep a significant difference:

https://youtu.be/Tu23Xr5wMo8?t=1093

https://youtu.be/ck11vzZOVtU?t=31

The signal on the 8500A has much less atenuation from the waverunner ... Better sample rate /  probes maybe is counting ....
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 19, 2019, 12:26:16 pm
About the potentiometer i thought you got more amplitude to the same setting, but it yeahh.. To hold the jig in place maybe some plastic clamps or using the cell phone holders with bendable bracket. I bought one to secure the multimeter probes . It has a clamp that goes into the table and the cell phone part  that has rubber to attach the the leads.

Search for "Flexible 360° Clip Mobile Cell Phone Holder " on fleebay, avazone or local store. They are cheap as 3 Euro.

Here is an example:



Check out Flexible 360° Clip Mobile Cell Phone Holder Lazy Bed Desktop Bracket Mount Stand
 https://ebay.us/UvAwdP



Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 19, 2019, 09:03:22 pm
I never played / tested fiber optics, only coax cable,although now internet these days are fiber opttcs laying around the floor hidden in furniture :P I've used in work some equipment with fiber optics but on the software / firmware side and with heavly warning about do not touch this cable :P


About attenuation i mispoke ou speak poorly my english , the sentence is a mess indeed. I wanted to say it had less amplitude . The better sample rate and probes refers to the results about the TOF  values on the 8500A.

Machining a block thats a neat idea, time consuming. The other way could be modeling clay but that would take a while to dry.

Now about handheld robustness. My cheapo 10 euro mini tool busted affter 2 years and 1 month after waranty :P it smoked and stopped working. I open the brushes compartiment and one metallic tab was broken as well the spring. there was also something rattling inside and had to open the tool to remove the remainings of the spring.... I attached another spring to the breaked one and works good with low loads such as plastic.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 19, 2019, 10:41:05 pm
Well not to bad that Harbour Freight , but i believe the one i've got is even worse, it is the basic version of the Guild 130W rotary tool.  the plastic stinks horribly even the mains cord. Inside it is very loose plastic holding the brushes.Now it lost its torque and stability.

I got a new one from lidl lets see how long it will last . Doesn't stink, has a good grip , very stable. Not a real dremel, i've used one and it is another beast :P

Sorry if i digress from the main subject but it like to show tools that lasts the waranty and a few more days, open them up and see what it can be done, learned :P

Now back to the subject , i see some projects regarding TDR in amateur radio and they use wood table and a lot of coax cable, and element14 sheet of paper, but of course it is just for explanation , not much for accuracy:

http://kf5iuy.blogspot.com/2012/08/a-poor-mans-introduction-to-tdr.html (http://kf5iuy.blogspot.com/2012/08/a-poor-mans-introduction-to-tdr.html)

https://www.element14.com/community/groups/test-and-measurement/blog/2014/05/12/33622a-arbitrary-waveform-generator-used-for-tdr-time-domain-reflectometry (https://www.element14.com/community/groups/test-and-measurement/blog/2014/05/12/33622a-arbitrary-waveform-generator-used-for-tdr-time-domain-reflectometry)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 20, 2019, 08:52:56 am
Uni-t's everywere. Here we have some local electronic shops that are official distributers of the uni-t brand and some big ones that sells like the xindar models that i've showed other post. I bought the first rotary tool here, in a outlet big store since the shop was going to close.. Another big one opened.with their lefting stock :D :

https://www.aki.pt/ferramentas/ferramentas-eletricas/mini-ferramentas/mini-ferramentas/miniferramentacom40acessoriospractyl130w-p66515.aspx (https://www.aki.pt/ferramentas/ferramentas-eletricas/mini-ferramentas/mini-ferramentas/miniferramentacom40acessoriospractyl130w-p66515.aspx)

Yesterday i bought this one :P which is much near to get ( the site is german but was still available on local store).

https://www.lidl.de/de/parkside-feinbohrschleifer-pfbs-160-b2/p277911 (https://www.lidl.de/de/parkside-feinbohrschleifer-pfbs-160-b2/p277911)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 20, 2019, 09:42:22 am
Looks like they are selling some UNI-T products now as well.   That's a large markup.

https://www.harborfreight.com/professional-commercial-and-residential-multimeter-64021.html (https://www.harborfreight.com/professional-commercial-and-residential-multimeter-64021.html)
That IS some serious markup! For us that are "in the know", that would get two 101's before any of the foreign policy taxes taxes kick in.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 21, 2019, 09:01:18 pm
And what about screw pole testers with CAT II. Good for discharging bug zappers. capacitors, pry boxes, and open the mini rotary tool brush compartiment :P
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 25, 2019, 07:04:16 pm
And what about screw pole testers with CAT II. Good for discharging bug zappers. capacitors, pry boxes, and open the mini rotary tool brush compartiment :P


And here is some tests regarding this Neon  "killer" screwdrivers by photoninduction. Also he tested a 1000V isolated screwdriver ... very tought one :P

https://www.youtube.com/watch?v=AGXQNLq19FQ&t=346s (https://www.youtube.com/watch?v=AGXQNLq19FQ&t=346s)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2019, 09:48:11 pm
Hi Joe

strange protections...


I want to apologize to anyone who made the mistake of clicking on that link.  Sadly, I can't control what people post in this thread.     Maybe I can have Dave lock it as I doubt I will do very many more tests on handhelds.     


I did however finally run the test for Mr Fungus.   
https://www.youtube.com/watch?v=Bar4VLt9KFM (https://www.youtube.com/watch?v=Bar4VLt9KFM)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on May 26, 2019, 09:52:29 pm
So we endure another cheap DMM video.. I've already been raked and baked :palm: so I'll just sit back to watch the fireworks..
*edit - wow! that fuse lit pretty fast. Joe beat me to the punch!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 26, 2019, 10:51:31 pm
So we endure another cheap DMM video.. I've already been raked and baked :palm: so I'll just sit back to watch the fireworks..
*edit - wow! that fuse lit pretty fast. Joe beat me to the punch!

Cliff, I do think you are right about the lack of interest in the subject.   While the ratios continue to look good in the poll,  the number of people participating reflects what I have been seeing in the channel's stats.   

I have written Dave, asking for him to go ahead and lock this thread.   While I wouldn't mind spending some time cleaning it up and making a table of contents for it as was suggested, I think Dave would have to allow me full access to pull it off.   

I still plan to eventually run the new version of the 121GW when it becomes available but I will place that information in the dedicated threads for that meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on May 26, 2019, 11:30:03 pm
Joe, Dave might be able to offer you the ability to lock your own thread.
One I started in the Supporters Lounge had a lock that i could apply should the thread get out of hand however i never used it for fear that I couldn't unlock it.

I suggest you discuss this option with Dave.
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 27, 2019, 12:01:41 am
Hi Joe

strange protections...


I want to apologize to anyone who made the mistake of clicking on that link.  Sadly, I can't control what people post in this thread.     Maybe I can have Dave lock it as I doubt I will do very many more tests on handhelds.     


I did however finally run the test for Mr Fungus.   
https://www.youtube.com/watch?v=Bar4VLt9KFM (https://www.youtube.com/watch?v=Bar4VLt9KFM)

I wonder how thermal cycling would affect them?  And do those meters measure the same in a 110F electrical closet as it would in a subzero testing chamber?
(http://www.us.mahle.com/media/global/products-&-services/services/engine-testing/abbildung-2_textimage.jpg)
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on May 27, 2019, 12:13:05 am
Some lack of participation may be due to the inspiration you've freely given to all, including the feckless copy artist's who don't know their ass from a hole in the ground.. Also the instruments market doesn't seem to be taken seriously now, since the Asian market has been dumping unsafe crap everywhere. I think we're all suffering fatigue with new whiz-bang junk appearing every 90-days, it just doesn't stop. Whatever you decide, you have earned my respect.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 27, 2019, 12:17:43 am
Hi Joe

strange protections...


I want to apologize to anyone who made the mistake of clicking on that link.  Sadly, I can't control what people post in this thread.     Maybe I can have Dave lock it as I doubt I will do very many more tests on handhelds.     
Instead of locking the whole thing, why not delete the off topic post instead?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2019, 02:15:13 am
Joe, Dave might be able to offer you the ability to lock your own thread.
One I started in the Supporters Lounge had a lock that i could apply should the thread get out of hand however i never used it for fear that I couldn't unlock it.

I suggest you discuss this option with Dave.

It sounds like making me a moderator for this one thread isn't a simple task.   

Instead of locking the whole thing, why not delete the off topic post instead?
   

It's a pretty decent sized thread with some pretty useless posts which make it more difficult to locate the data is all.  I would have liked to have cleaned some of it up as part of making a TOC for it,  then just lock it down.   It was really up to the people posting to decide if they wanted a thread with cat sandwich pictures or something else.    I just asked if he would go ahead and lock it as is.     

Some lack of participation may be due to the inspiration you've freely given to all, including the feckless copy artist's who don't know their ass from a hole in the ground.. Also the instruments market doesn't seem to be taken seriously now, since the Asian market has been dumping unsafe crap everywhere. I think we're all suffering fatigue with new whiz-bang junk appearing every 90-days, it just doesn't stop. Whatever you decide, you have earned my respect.

Cliff, the channel has been in the decline for several months.  It's hard to say if posting my test results had an impact outside of maybe selling a few meters for Brymen.    My goals for this were always for my own personal interest,  not to sell meters or make any money at it.   In that respect, I am happy with the result. 
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 27, 2019, 07:12:04 am
Cliff, the channel has been in the decline for several months.  It's hard to say if posting my test results had an impact outside of maybe selling a few meters for Brymen.    My goals for this were always for my own personal interest,  not to sell meters or make any money at it.   In that respect, I am happy with the result.

I think you've helped move a few Uni-T's as well.

Anyhow the last few videos felt a little different from all your previous videos, starting with the Mother Nature Takes Her Turn (which was quite long and I didn't really understand this video).   One thing I see is that videos featuring popular cheap Chinese meters do well, and anything with Fluke also seem to attract viewers. 


 
Title: Re: Handheld meter electrical robustness testing.
Post by: bc888 on May 27, 2019, 01:14:16 pm
Joe, I believe that I've made it through the thread without posting any nonsense (yet). So here it is now. Sorry to see you are burned out from all the tests. Speaking for myself, I've enjoyed this more than you imagine.  Regarding your comment from above "It's hard to say if posting my test results had an impact outside of maybe selling a few meters for Brymen." It did for me, and any mfg worth their salt would be looking at these tests and trying to make a meter that handled them better in the future. To that end, you have done all of us a service.

I bought a few old Fluke 27/FM's that test out good. Lets just say that 8 good ones and one that doesn't work due to emotional issues from a battery leak is more than I need. Not sure what happened that I got 9 of these as one would have been good, 2 plenty. Classic TEA (test equipment anonymous) screed I suppose. One moment I'm looking at an Ebay sale screen and the next thing I know my fingers are shaking and I needed to buy them....anyway, I see you didn't test any 27/FM's and I have too many. Like to send you one or two to blow up if you haven't folded up your tent and called it a day yet.

Regardless, thank you again for sharing your tests.

Edit: rather than do a new post, response to below: I had read the FAQ when I first started reading the thread and glossed over that part, thanks for the reminder. If you change your mind, let me know and Joe, the tests you did were very engaging and worthwhile. Thank you again for sharing it all.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 27, 2019, 04:46:09 pm
About deleting if you want me to delete the things related to my battery tests or the chess pieces, since they are not properly standarized or fully tested please let me now. I'll do and again apologize for poluting this thread.  I didn't put enought effort  but i'd like to finnish the current measure for the ut204A using the dummy battery and try to learn with mistakes because this particular meter its a battery hogger .

I think people want cheap meter because they miss the bast shield arc events and slow camera :P but could be wrong....

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2019, 07:54:58 pm
I think you've helped move a few Uni-T's as well.

Anyhow the last few videos felt a little different from all your previous videos, starting with the Mother Nature Takes Her Turn (which was quite long and I didn't really understand this video).   One thing I see is that videos featuring popular cheap Chinese meters do well, and anything with Fluke also seem to attract viewers. 

The only UNI-T product I have had a use for was the UT210, as a DC current clamp.  I'm certain I helped sell a few of these. 

Obviously, the lest several videos didn't included new meters.  A couple of them have been non DMM related.  So I am sure you are not alone in feeling they were a little different from the previous ones. 

On the Brymen pocket meter, I let the battery drain down a few times, tossed it outside for the Fall and Winter months, then subjected it to some vibration.   You would really have to help me understand what you don't understand,  if you want me to help.

I bought a few old Fluke 27/FM's that test out good. Lets just say that 8 good ones and one that doesn't work due to emotional issues from a battery leak is more than I need. Not sure what happened that I got 9 of these as one would have been good, 2 plenty. Classic TEA (test equipment anonymous) screed I suppose. One moment I'm looking at an Ebay sale screen and the next thing I know my fingers are shaking and I needed to buy them....anyway, I see you didn't test any 27/FM's and I have too many. Like to send you one or two to blow up if you haven't folded up your tent and called it a day yet.

 :-DD

Thanks for the feedback.  I'm looking forward to having a look at the next revision of the 121GW along with the Sanwa pocket meter.   I don't see too many meters out there I am interested in looking at.   It takes about two days to run a set of tests over the course of a week, depending how well a meter is designed and what tests I subject it to, so I tend to be more selective with the ones I look at.   

I created a FAQ.  You can find a link to it in my very first post of this thread.  In there you will find I talk about the reasons why I don't run old meters.  The Fluke 87V was a good example of why not to do this.   While I did look at a Fluke 189, I didn't include the data I collected in the spreadsheet.   


About deleting if you want me to delete the things related to my battery tests or the chess pieces, since they are not properly standarized or fully tested please let me now. I'll do and again apologize for poluting this thread.  I didn't put enought effort  but i'd like to finnish the current measure for the ut204A using the dummy battery and try to learn with mistakes because this particular meter its a battery hogger .

I think people want cheap meter because they miss the bast shield arc events and slow camera :P but could be wrong....

As I stated above,  "It was really up to the people posting to decide if they wanted a thread with cat sandwich pictures or something else.".   I took a few hours and went through it (second time I have done this since starting the thread).  I managed to remove a couple of my own dead links in the process.   I really didn't see enough off topic posts to make much of a difference in the size of the thread even if I were allowed to clean it up.     

Nothing more from Dave as far as locking it down.   Maybe there is a way to make a dynamic linked TOC.   Currently working on a static one. 
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 27, 2019, 09:23:57 pm
I think you've helped move a few Uni-T's as well.

Anyhow the last few videos felt a little different from all your previous videos, starting with the Mother Nature Takes Her Turn (which was quite long and I didn't really understand this video).   One thing I see is that videos featuring popular cheap Chinese meters do well, and anything with Fluke also seem to attract viewers. 

The only UNI-T product I have had a use for was the UT210, as a DC current clamp.  I'm certain I helped sell a few of these. 

Obviously, the lest several videos didn't included new meters.  A couple of them have been non DMM related.  So I am sure you are not alone in feeling they were a little different from the previous ones. 

On the Brymen pocket meter, I let the battery drain down a few times, tossed it outside for the Fall and Winter months, then subjected it to some vibration.   You would really have to help me understand what you don't understand,  if you want me to help.

The issues I had with the video were:
1. You mention in the intro you decided to buy an Amprobe PM55A to see if you can get it to fail in the same manner as an EEVBLOG member who bought a few of these, but don't mention what the failure was... I'm wondering what's the point throughout the video, and eventually I lose interest.

2. The title says Brymen BM27s but why are you testing an Amprobe? 

3. You then discharge a battery and subject it to different environmental conditions... ok... but what are we looking for?  Still don't understand the failure for which you're testing.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 27, 2019, 11:14:19 pm
I think you've helped move a few Uni-T's as well.

Anyhow the last few videos felt a little different from all your previous videos, starting with the Mother Nature Takes Her Turn (which was quite long and I didn't really understand this video).   One thing I see is that videos featuring popular cheap Chinese meters do well, and anything with Fluke also seem to attract viewers. 

The only UNI-T product I have had a use for was the UT210, as a DC current clamp.  I'm certain I helped sell a few of these. 

Obviously, the lest several videos didn't included new meters.  A couple of them have been non DMM related.  So I am sure you are not alone in feeling they were a little different from the previous ones. 

On the Brymen pocket meter, I let the battery drain down a few times, tossed it outside for the Fall and Winter months, then subjected it to some vibration.   You would really have to help me understand what you don't understand,  if you want me to help.

The issues I had with the video were:
1. You mention in the intro you decided to buy an Amprobe PM55A to see if you can get it to fail in the same manner as an EEVBLOG member who bought a few of these, but don't mention what the failure was... I'm wondering what's the point throughout the video, and eventually I lose interest.

2. The title says Brymen BM27s but why are you testing an Amprobe? 

3. You then discharge a battery and subject it to different environmental conditions... ok... but what are we looking for?  Still don't understand the failure for which you're testing.

In the description, there was a link to True's original posts along with the original video.  Had you watch the original video or followed the thread point to in the link, you would have known that the Amprobe rebranded this meter and they are one in the same. 

My goal for running this meter was always to try and replicate what member True had posted.  Their details were sparse at best and indeed, it could have very well have been a troll post.  They stopped posting and I went ahead and did what I could to try and see if indeed these meters have a weak spot.   Of course, if you are leaving your test equipment outside all Winter long, your an idiot but it's good to know that the meter seems to be a lot more robust than what had been posted.   Of course, True is always free to chime in and add some additional clues.  I would be more than happy to subject this meter to anything they could come up with as a possible cause. 

****

Funny, I just watched the first minute and half of this video.  I think you lost interest before that.   :-DD :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 27, 2019, 11:58:53 pm
The issues I had with the video were:
1. You mention in the intro you decided to buy an Amprobe PM55A to see if you can get it to fail in the same manner as an EEVBLOG member who bought a few of these, but don't mention what the failure was... I'm wondering what's the point throughout the video, and eventually I lose interest.
2. The title says Brymen BM27s but why are you testing an Amprobe? 
3. You then discharge a battery and subject it to different environmental conditions... ok... but what are we looking for?  Still don't understand the failure for which you're testing.

In the description, there was a link to True's original posts along with the original video.  Had you watch the original video or followed the thread point to in the link, you would have known that the Amprobe rebranded this meter and they are one in the same. 
The link to the original video works.  The link to True's original posting does not go back to anything related to his post.  But the point is, it would be helpful to the viewer if all relevant information could be included within the video, and not have to have the viewer stop the video, go back to review another video or thread, before resuming in order to understand its content.  I hope you take this as constructive criticism; I'm not trying to bash your video.


Funny, I just watched the first minute and half of this video.  I think you lost interest before that.   :-DD :-DD

What makes you believe that?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2019, 12:32:00 am
Funny, I just watched the first minute and half of this video.  I think you lost interest before that.   :-DD :-DD
What makes you believe that?

Quote
2. The title says Brymen BM27s but why are you testing an Amprobe? 

First 10 seconds:

Hello again
Some time ago I made a video on this Brymen BM27s pocket meter
This one happens to be sold by Amprobe with the part number PM55A

Of course, maybe you did not understand that meant that Brymen made this meter for Amprobe.   You would have needed to use the page down key a few time to locate True's original posts. 

I assume that the people watching these videos have the ability and desire to learn more about the subject and will do their own research.   Not to point out the obvious, but that's actually all this thread has been about, me doing a little research.  No one is spoon feeding me this data.  I'm sorting out the tests and running them on my own.   I'm sure that's a foreign concept to a few people but I image for most people working in the technical sectors, it's a fairly common practice.   
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 28, 2019, 01:34:05 am

First 10 seconds:

Hello again
Some time ago I made a video on this Brymen BM27s pocket meter
This one happens to be sold by Amprobe with the part number PM55A

Yes it was unclear, at least to me, what "this" was... there was no Brymen pocket meter (nor any meter) shown, and only an empty Amprobe package.
Then you seemed to introduce a second a second meter, the Amprobe PM55A... at least that's how I interpreted it.  I ended up waiting for an explanation of the relationship between the two different meters.  I did later deduce that its the same meter but was confused initially.  I posed the question "why are you testing an Amprobe?" as a rhetorical question; one that probably many viewers likely had before finally deducing this bit of information (or through research conclude its the same meter).  Just a few words about this might have conveyed this information and reduced any confusion. 

I assume that the people watching these videos have the ability and desire to learn more about the subject and will do their own research.   Not to point out the obvious, but that's actually all this thread has been about, me doing a little research.  No one is spoon feeding me this data.  I'm sorting out the tests and running them on my own.   I'm sure that's a foreign concept to a few people but I image for most people working in the technical sectors, it's a fairly common practice.   

I've done some research but I STILL cannot find this "True" person's original posting... and I still don't know what failures this person had with his Brymens.  I'm assuming its something environment-related.  Again, just a few words on his problems would have made the video easier to follow. 

[UPDATE:]
Ok I finally found it buried much earlier in the thread.  So... if that video was targeted only for those who have actively been following this thread since at least mid last year, then it would make sense.  If you want to target the video to a more general technical audience, then it would have been helpful to maybe list the issues True mentioned in the thread, for which you were testing.  I, for one, started watching your videos before I even joined EEVBLOG.  Most if not all of them stood on their own, without the viewer having to wade through threads on a forum to understand the point of the video. 

I respect your decision to exclude this information in the video.  I'm just pointing out what I experienced. 
For those who are still "lost" as I was, here's the post to which the video is referring:


A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.

What happens:
- Auto mode freaks out and doesn't work (a short shows an unstable high resistance for example)
- Short detect mode shows shorted
- EF (power stick) mode works
- I can't remember what Low-Z volts does
- Hi-Z voltage works
- Diode mode acts like a short
- High ohms varies from not working to usually sounding the "shorted" beeper; IIRC high ohms will not give a stable reading
- Haven't tested current

What causes this?

The only similar thing I could find was a dying battery.

I purchased a new unit after my PM55A had failed, only to find a PM55 I gave to a friend also failed. I tested a PM55 I had and it too had failed. The replacement? Well, it tested good (testing 5V in auto mode, and shorting probes, that's it...); after a month when I went to use it to test a low voltage DC circuit again, it showed low battery ... and sure enough it failed too.

I'd like to fix them but have no idea where to start or what could have failed.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2019, 02:30:43 am
Quote
[UPDATE:]
Ok I finally found it buried much earlier in the thread.  So... if that video was targeted only for those who have actively been following this thread since at least mid last year, then it would make sense.  If you want to target the video to a more general technical audience, then it would have been helpful to maybe list the issues True mentioned in the thread, for which you were testing.  I, for one, started watching your videos before I even joined EEVBLOG. Most if not all of them stood on their own, without the viewer having to wade through threads on a forum to understand the point of the video.

Are you sure you are watching my videos??   These tests have been difficult it seems for many people to follow.  I created the FAQ to help address this and it did seem to curb some of the more common questions people had.   The fact you feel they stand on their own is amazing.  Without this thread to provide some level of context, I am surprised anyone could have followed along.  Even with the thread, unless you have a EE background I would think it would be difficult.   It's definitely a niche subject.   

So far you have been the only one who voiced their confusion over the rebranding.   Not that others were not lost as well but for the most part it doesn't seem to have been a problem.   Perhaps it's because most people who are interested in the topic are aware of how common rebranding is.   

The description states  "You may find the original posts here:"
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/2775/ (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/2775/)

While the actual posts started on that same page at: 
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/2790 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/2790)

Had you had taken the time to watch the first five minutes of the first video, I read what True had posted.  But I wasn't going to do that for every video going forward.  That's why I provide the links for people to do their own background search. 
https://youtu.be/0D_6uOFSgyY?t=201 (https://youtu.be/0D_6uOFSgyY?t=201)

Of course, if you choose to jump in the middle of a longer term test like this I expect you to be lost.   I normally start reading a book at the beginning for this same reason.   
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on May 28, 2019, 03:21:12 am
My mistake.  Sorry for the confusion...
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 28, 2019, 11:41:27 am
I did however finally run the test for Mr Fungus.   

Thanks!

Basically not much difference between the worm gear types and rotary ones. Didn't expect that.

And I learned a new word: "Diddlestick".

(I actually own a blue Bournes diddlestick  :) )
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on May 28, 2019, 04:48:14 pm
I guess the advantage of the worm gear ones is that they have very fine adjustment and are harder to damage with a ham fist.

From what I've seen they also have multiple wipers making contact with the carbon.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on May 28, 2019, 06:45:15 pm
I'm guessing they were called diddle sticks long before my time.   

I forgot to add the last "/" to the TOC.  It should all work now.   Per Windsmurf's comments, obviously the links will only get you to the top of the page.  You may need to hunt around a bit from this location to find what you are looking for.
I know you already did the work, but to go directly to a specific post, right-click on its title and copy the link.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=748746)
For example, the link to The Brymen BM869s, It's 14KV or Bust is:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1407796/#msg1407796 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1407796/#msg1407796)

(the message ID never changes)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on May 28, 2019, 11:27:48 pm
Now THAT is what I call useful feedback!   

***

I have gone ahead and updated the TOC.   While going through it, I noticed a few others that seemed worth linking.    I also blew away a few more of my own posts that were not related to handheld mulltimeters.     The TOC should help avoid some of the other non related posts.   

Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on May 29, 2019, 01:21:12 am
Great job organizing the OP, Joe. That's a lot of info! :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 29, 2019, 08:22:18 am
Hi.

Nice work on the static links on the first post. It looks like a history . I have a question. Does it appear always whether the post you're reading? I can only see the links when i hit the print button .

Have also turned off the ad blocker but no effect just to be sure :S I'll attach an example of a print on pdf format so you can see. Again i could be doing something wrong or not seeing properly :P

the document is too big for attachment. here is the doc :

https://drive.google.com/open?id=1nuwirpJ9RUXKu3heGG4KU_P8TOJPNmTg
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on May 29, 2019, 08:32:24 am
Hi.

Nice work on the static links on the first post. It looks like a history . I have a question. Does it appear always whether the post you're reading? I can only see the links when i hit the print button .

Have also turned off the ad blocker but no effect just to be sure :S I'll attach an example of a print on pdf format so you can see. Again i could be doing something wrong or not seeing properly :P

the document is too big for attachment. here is the doc :

https://drive.google.com/open?id=1nuwirpJ9RUXKu3heGG4KU_P8TOJPNmTg

Nevermind the print prints all the threads ... never tried out to be honest... bummer :S sorry. My question now  if there is a way to put a permant link or permalink on the thread, for example the poll that keeps always on the thread regardless of the post you're watching.
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on May 29, 2019, 08:36:33 am
Thanks for the effort creating TOC. Nice of you, and makes this topic even better.
Regards,
Siniša
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 01, 2019, 07:22:01 pm
This thread has been great, I've personally learned a lot and been put in my place a couple of times, but I agree, there's not really anywhere to go from here. It's time to wrap it up.  :'(

Thanks for all the work, Joe.  :-+

A whole bunch of meter's electrical limits have been found, their weak points have been identified, experimental improvements have been made, everything has been well documented and anybody who's followed this saga must surely have learned a lot about how multimeters do their thing.

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 01, 2019, 07:41:48 pm
Enjoy

You sure get a lot of weather over there.  :popcorn:

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on June 07, 2019, 06:02:07 pm
Just thinking out load of a big finale for this thread...

Maybe you could find out how many volts it takes to zap a Fluke 101? It would need a beefed-up generator but that could be a fun challenge.  :popcorn:
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 07, 2019, 11:42:26 pm
Dave did not want to close it because it is a popular place to discuss power tools.    :-DD  I guess it ranks in the top 10??!!  I never would have guessed this. 

I didn't plan on doing anything more with it, which is why I was suggesting it be locked.  If I do some big finale, it will be to finally put that latest thicker PCB version of the 121GW through it's paces.   No place to hide this time around.    :-DD

I would like to do some sort of comparison with the pocket meter Dave is selling as well.  I beat the shit out of that Brymen pocket meter.  Maybe the Sanwa can handle that level of abuse....

No need for a beefed up generator as that work was done some time ago.  I suspect the 101 would e damaged around the same levels that finally damaged the 107.   
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on June 08, 2019, 01:44:50 am
Really sad to hear these tests or at least this thread may be coming to an end. I'm mostly a lurker around the forum, but this has been one of my favorite threads for a long time. I'd personally hoped to see many more meters run. Perhaps as time goes on joeqsmith will find more he is interested in running or someone else will take it upon themselves to do more tests. One of the things I've always appreciated about Joe is his encouragement of others to run similar tests for themselves. I only wish I had the time, money, and honestly the skills to consistently do such methodical testing, but alas I'm a lowly hobbyist that is already outclassed by some of the equipment I own and too many gaps in knowledge to be beneficial to anyone. It has been fascinating, educational, and I'll forever be grateful to Joe for having shared this bit of his hobby with us. I have so much respect for him and the extent to which he has gone to satiate curiosity. It is frankly amazing.
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on June 08, 2019, 01:46:26 am
I bought two of those Sanwas from Dave. Dare you to give one the full joeqsmith TREATMENT! :)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 08, 2019, 11:05:09 am
Well This thread is very popular due to the various tests on the meters, methods implied, documentation provided, some funny stuff.

Sanwa's are going to the robustness test? do you're best :P

Can i post the results using the modeled  dummy 9V battery for current draw and voltage shut down? this time using this setup, not sure if it is  the best :

- Power supply is a homemade Joy-it DPS5005 ( http://anleitung.joy-it.net/?goods=dps5005 (http://anleitung.joy-it.net/?goods=dps5005) ) box powered by a 12V SLAB battery, setup 9V to and current limit of 100mA (maybe too low ? ). The voltage will be ajusted to check the shutdown point of DUT ( uni-t ut204A , the battery hogger) and thus ignoring the battery indicator
- Measure of voltage shutdown point will be measured with multimeter to confirm with the power supply ( rounded to 1 decimal place)
- Current will be measured with another multimeter in series with power supply and one of the terminals of dummy battery.
- All connections between power supply , current measurement and dummy are banana jacks 
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 13, 2019, 09:13:40 pm
I'm enjoying watching the thermal cycling videos.
Interesting how the different meters seem to react differently to temperature changes. 
Owon seemed to do poorly... wonder if that has anything to do with potential condensation on the board or components?

Also now I wonder what do those specs mean? 
DC Voltage, 869s, 500.00mV, 5.0000V, 0.02% + 2d

I saw the Brymen start at around 0.998mV, then go up to maybe 1.016mV, then down to 0.992mV

To calculate 0.02%, do you multiply that against the range? 500.00mV x (0.02/100) = 0.1mV?  Since the display shows down to 1uV, does "2d" mean + 2uV?
If measuring 1.000mV, then would it be in spec if the Brymen 869s showed anything between 1.102mV and 0.898mV?





Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on June 13, 2019, 09:22:53 pm
Also now I wonder what do those specs mean? 

I explain about multimeter specifications here: https://lygte-info.dk/info/DMMTolerances%20UK.html
Usual they are only valid between 18°C to 28°C, for each degree outside you must add some more tolerance.
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 13, 2019, 10:35:48 pm
Also now I wonder what do those specs mean? 

I explain about multimeter specifications here: https://lygte-info.dk/info/DMMTolerances%20UK.html
Usual they are only valid between 18°C to 28°C, for each degree outside you must add some more tolerance.

Thank you, that's a nice explanations page you developed!

So, then for the Brymen 869s in the video, specs for the 500.00mV range is:
DC Voltage, 869s, 500.00mV, 5.0000V, 0.02% + 2d

And since this spec is for 50,000 count range, I think I need to drop the last digit from the 500,000 count readings shown in the video (is this correct?).

Since Joe is measuring 1.00mV (assumed), according to the spec, readings should be:
1.00mV x 0.02% = 0.0002mV, and add 2 counts of 0.01mV and you get 0.0202mV, or for the meter 0.02mV.

So to meet specs, the meter needs to show something between 1.020mv and 0.980mV... is this right?






Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on June 14, 2019, 05:04:40 am

So, then for the Brymen 869s in the video, specs for the 500.00mV range is:
DC Voltage, 869s, 500.00mV, 5.0000V, 0.02% + 2d

And since this spec is for 50,000 count range, I think I need to drop the last digit from the 500,000 count readings shown in the video (is this correct?).

Since Joe is measuring 1.00mV (assumed), according to the spec, readings should be:
1.00mV x 0.02% = 0.0002mV, and add 2 counts of 0.01mV and you get 0.0202mV, or for the meter 0.02mV.

So to meet specs, the meter needs to show something between 1.020mv and 0.980mV... is this right?

Yes, but again only in a limited temperature range, Joe goes well outside that range.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 14, 2019, 02:01:20 pm
From Page 17 of the BM869s manual:

Electrical Specifications
Accuracy is +/-(% reading digits + number of digits) or otherwise specified, at 23C +/- 5C &
less than 75% relative humidity.

Keep in mind that during the transition, all of the components may not track.  That difference can cause a fair amount of error and is why the meter is allowed to stabilize for a half hour.   There is a fair amount of air movement but even a half hour may not be enough to some of the meters to settle.   

Why push them way outside their rating?  I was asked this early on.  Pretty much the same reason I transient test them to failure. 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 14, 2019, 02:48:59 pm
Also remember in manual that the bigger temperature ranges refers to working and storage conditions :P

In the videos spotted some condensation which can increase humidity and could add up some digits, but brymen and uni-t are very stable in that test, so not  huge impact indeed.

Thanks for the tests provided. Did one of the meters  have become drifted after the test, for example the owon B41?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 14, 2019, 02:59:36 pm
Thanks for the tests provided. Did one of the meters  have become drifted after the test, for example the owon B41?

They all returned to normal after a day.
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 14, 2019, 05:51:05 pm
Yes, but again only in a limited temperature range, Joe goes well outside that range.

Yes I understand that... and yet the meter stayed in-spec regardless of the out-of-spec temperature (and condensation) condition, which is impressive.  I wonder if Flukes do as well... I'm guessing probably the industrial ones will (or maybe all?). 
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 14, 2019, 07:10:47 pm
Thanks for the tests provided. Did one of the meters  have become drifted after the test, for example the owon B41?

They all returned to normal after a day.

Thats good news ohhh and the little pocket brymen / amprobe still functional for that testing... eehehehe ? That had a bad time for a lot of time :P Some of you're tests change  decision on the meter for develop things with triacs :P The little blue one .... otherwise would be ut61E
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 15, 2019, 05:21:08 pm
Yes, but again only in a limited temperature range, Joe goes well outside that range.

Yes I understand that... and yet the meter stayed in-spec regardless of the out-of-spec temperature (and condensation) condition, which is impressive.  I wonder if Flukes do as well... I'm guessing probably the industrial ones will (or maybe all?).

Old Fluke 189
https://www.youtube.com/watch?v=GspyOVkh3K0 (https://www.youtube.com/watch?v=GspyOVkh3K0)
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 15, 2019, 05:59:24 pm
Ohh crap was  the leads or input jacks ? Or is the default error message for anything bad ?
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 15, 2019, 08:27:07 pm
Thanks for the reply joe. The meter is quite interesting from the manual perspective and also pdf with text is available.
 
Lets see how other fluke's perform... .. 87V , 17B+ and 115 if they are on the menu :P

Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 15, 2019, 11:19:26 pm
Ohh crap was  the leads or input jacks ? Or is the default error message for anything bad ?

Leads or Fuse error message pops up if you're not in the amps range dial with a lead in the amps input, or you're in the amps range and you have no lead in the amps input or you have a bad fuse.
I get that when I clean the input jack on my 189 with a Q-tip with too much rubbing alcohol, until it dries out.  I think the condensation shorted the amps range input sensor.

Its interesting that the 189 specs have a very wide operating temperature range of -20°C to +55°CC, and even gives you a temperature coefficient for measurement at <18 °C or >28 °C.      Such detail is probably one of the reasons Fluke has become a standard in U.S. Industry.   
It did seem to fall out of the 20 count spec for some duration... I'm guessing due to the condensation? I wonder what parts are affected by it... I'm guessing an analog part like the PTC?  Or more generally some current leak on the board in the analog input section.  I bet some insulating coating on the board can eliminate the condensation effect.
 
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763911;image)
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763917;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 16, 2019, 12:02:12 am
It did seem to fall out of the 20 count spec for some duration... I'm guessing due to the condensation? I wonder what parts are affected by it... I'm guessing an analog part like the PTC?  Or more generally some current leak on the board in the analog input section.  I bet some insulating coating on the board can eliminate the condensation effect.


Keep in mind that during the transition, all of the components may not track.  That difference can cause a fair amount of error and is why the meter is allowed to stabilize for a half hour.   There is a fair amount of air movement but even a half hour may not be enough to some of the meters to settle.   

Put two thermometers outside, one in a glass of water the other in open air.  One will respond slower.  This delay can cause a fair bit of error and again is why I let them settle.       

In the mV range the input impedance of a crap meter is a Meg.  The PTC is about 1.5K.  Say the PTC changes 100%.  What's the total error it causes? 
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 16, 2019, 12:13:34 am

Put two thermometers outside, one in a glass of water the other in open air.  One will respond slower.  This delay can cause a fair bit of error and again is why I let them settle.       

In the mV range the input impedance of a crap meter is a Meg.  The PTC is about 1.5K.  Say the PTC changes 100%.  What's the total error it causes?

That makes sense... so definitely nothing to do with the PTC.  So in your opinion, do you think the error is caused more by uneven temperatures of the components, and less by condensation's effects on the board?   
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 16, 2019, 01:20:43 am

Old Fluke 189

Hi Joe I just noticed the low battery indicater is on, on the 189. 
That gets me thinking... are battery outputs changing with the temperatures, and how much of an effect that plays in the readings...

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763947;image)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 16, 2019, 02:30:22 am
The 189 predates the use of NiMH.  The lower voltage causes this meter, along with my camera and a few other devices to display a low battery.   This particular 189 will display a low battery at 4.89V.  At 4.5, it  will begin to flash and at 4.0 it cuts out.  With a mV applied, it will not change a count all the way down to cutout.   The batteries installed are EBL 2300.  The current voltage is 4.865.    So, no, this is not a problem.   


Quote
So in your opinion, do you think the error is caused more by uneven temperatures of the components, and less by condensation's effects on the board?   

When it comes to trying to solve problems, I find my opinions mean very little and data is pretty much everything.   :-DD   There are a few easy experiments that could be ran if we needed to sort it out.   The UT61E for example, drifted far worse.  It may have been the worse I have seen.  For less than the price of a coffee, I was able to tame it.  Then again, I wasn't considering my time having a cost.  If I did, the UT61E I have is worth a bit more than a standard one...   
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 16, 2019, 03:23:47 am
When it comes to trying to solve problems, I find my opinions mean very little and data is pretty much everything.   :-DD

Yes but I'd image you'd have an inclination based on your expert knowledge.   ;D

There are a few easy experiments that could be ran if we needed to sort it out.   The UT61E for example, drifted far worse.  It may have been the worse I have seen.  For less than the price of a coffee, I was able to tame it.  Then again, I wasn't considering my time having a cost.  If I did, the UT61E I have is worth a bit more than a standard one...

For our edification, may we know what you did to correct the UT61E drift issue?   :-/O

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 16, 2019, 03:53:03 am
It's good to know that the TOC was a waste of time. 
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 16, 2019, 04:38:43 am
It's good to know that the TOC was a waste of time.

You'd mentioned this in many of your videos (also listed on post #1), so I guess it's an unbending rule ;D.   
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 16, 2019, 04:51:33 am
It's good to know that the TOC was a waste of time.

You'd mentioned this in many of your videos (also listed on post #1), so I guess it's an unbending rule ;D.   

My bad I thought you were referencing your FAQ about not disclosing many of your modifications.... you actually do have a video on the thermal stability mod  ;D
Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: windsmurf on June 16, 2019, 06:16:47 am
...A few good articles if you are interested:

http://www.grainger.com/content/safety-digital-multimeter (http://www.grainger.com/content/safety-digital-multimeter)
http://cp.literature.agilent.com/litweb/pdf/5990-4578EN.pdf (http://cp.literature.agilent.com/litweb/pdf/5990-4578EN.pdf)
http://faculty.riohondo.edu/jfrala/fluke_multimeters_-_abcs_of_multimeter_safety_multimeter_safety_and_you_application_note.pdf
 (http://faculty.riohondo.edu/jfrala/fluke_multimeters_-_abcs_of_multimeter_safety_multimeter_safety_and_you_application_note.pdf)

Just FYI the 2nd and 3rd links didn't work for me.
I'm not sure if this is the same info I would have found in the 2nd link:
http://literature.cdn.keysight.com/litweb/pdf/5992-3426EN.pdf (http://literature.cdn.keysight.com/litweb/pdf/5992-3426EN.pdf)

I think this is the same pdf as the one pointed to from your third link:
https://content.fluke.com/promotions/promo-dmm/0518-dmm-campaign/dmm/fluke_dmm-chfr/files/safetyguidelines.pdf (https://content.fluke.com/promotions/promo-dmm/0518-dmm-campaign/dmm/fluke_dmm-chfr/files/safetyguidelines.pdf)




Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 16, 2019, 10:46:48 am
Ohh crap was  the leads or input jacks ? Or is the default error message for anything bad ?

Leads or Fuse error message pops up if you're not in the amps range dial with a lead in the amps input, or you're in the amps range and you have no lead in the amps input or you have a bad fuse.
I get that when I clean the input jack on my 189 with a Q-tip with too much rubbing alcohol, until it dries out.  I think the condensation shorted the amps range input sensor.

Its interesting that the 189 specs have a very wide operating temperature range of -20°C to +55°CC, and even gives you a temperature coefficient for measurement at <18 °C or >28 °C.      Such detail is probably one of the reasons Fluke has become a standard in U.S. Industry.   
It did seem to fall out of the 20 count spec for some duration... I'm guessing due to the condensation? I wonder what parts are affected by it... I'm guessing an analog part like the PTC?  Or more generally some current leak on the board in the analog input section.  I bet some insulating coating on the board can eliminate the condensation effect.
 
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763911;image)
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763917;image)

One of the interesting things of the manual is there is no mention to water resistance and yes there were water resistant watches back then, but check in the Physical Specifications the humidity ranges , it seems to be high for it's time as i repeated (sorry for this )in a comment on youtube, so probably the meter was ahead of it's time when it was developed / presented. 

Check the specs for the first model of the 87V ... they are the same  in terms of temperature and humidity ranges

Title: Re: Hear kitty kitty kitty, nope not that kind of cat
Post by: joeqsmith on June 16, 2019, 01:21:53 pm
...A few good articles if you are interested:

Just FYI the 2nd and 3rd links didn't work for me.

Not surprised.  It's an old post and the internet is not constant.  If you are planning to keep an updated list for links on safety, here is one you may want to add:   
https://brainfiller.com/arcflashforum/

I'm a bit surprised with the amount of discussions on meter safety that no one took the lead to create a thread for it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 16, 2019, 04:02:57 pm
There is this thread but maybe it's nothing compared to what is discussed, tested here, since it is a specific target multimeter thread

https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/ (https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/)

Now to make one similiar as yours it would require someone maybe to build similar test jig, test equipment,DMM's,  skillset, etc Its a unique thread where you pick up something that was not yet explored at diy world on Handheld meters.


Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 16, 2019, 04:31:48 pm
By the way here is an update for the battery testing on the UT204A in the DC 40 Amp's. Now there are not much of losses to care about from the previous experience with garbage crocodile cables :S 0.75m2 + crimped terminals + banana jacks .. 3.333 Ohms between power supply and meter. better measure voltage on input jacks with uni-t 50b ..[EDIT] its 8.97V on input jacks so it is much lower... need more resolution :D but this is an improvement.

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 16, 2019, 04:49:07 pm
By the way here is an update for the battery testing on the UT204A in the DC 40 Amp's. Now there are not much of losses to care about from the previous experience with garbage crocodile cables :S 0.75m2 + crimped terminals + banana jacks .. 3.333 Ohms between power supply and meter. better measure voltage on input jacks with uni-t 50b ..[EDIT] its 8.97V on input jacks so it is much lower... need more resolution :D but this is an improvement.

here is the measurement taken on the input jacks with DUT , voltage is the same in both points .

Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on June 20, 2019, 10:39:30 pm
Now this is a new thing.... a uni-t with two input jacks and inverted display.... ut123 ... is this the one who would lived up to the transient generator?
 It is so damn simple... a copy cat of some meter that we know...
https://www.ebay.com/itm/UNI-T-UT123-Digital-Color-Screen-High-Accuracy-Multimeter-for-Home-Industry-P2C9/382971551604?hash=item592ae21f74:g:FkcAAOSwbINc5rcR (https://www.ebay.com/itm/UNI-T-UT123-Digital-Color-Screen-High-Accuracy-Multimeter-for-Home-Industry-P2C9/382971551604?hash=item592ae21f74:g:FkcAAOSwbINc5rcR)

... besides the ut210E which is in fact very good...
Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 21, 2019, 12:42:38 am
Ohh crap was  the leads or input jacks ? Or is the default error message for anything bad ?

Leads or Fuse error message pops up if you're not in the amps range dial with a lead in the amps input, or you're in the amps range and you have no lead in the amps input or you have a bad fuse.
I get that when I clean the input jack on my 189 with a Q-tip with too much rubbing alcohol, until it dries out.  I think the condensation shorted the amps range input sensor.

Its interesting that the 189 specs have a very wide operating temperature range of -20°C to +55°CC, and even gives you a temperature coefficient for measurement at <18 °C or >28 °C.      Such detail is probably one of the reasons Fluke has become a standard in U.S. Industry.   
It did seem to fall out of the 20 count spec for some duration... I'm guessing due to the condensation? I wonder what parts are affected by it... I'm guessing an analog part like the PTC?  Or more generally some current leak on the board in the analog input section.  I bet some insulating coating on the board can eliminate the condensation effect.
 
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763911;image)
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=763917;image)

One of the interesting things of the manual is there is no mention to water resistance and yes there were water resistant watches back then, but check in the Physical Specifications the humidity ranges , it seems to be high for it's time as i repeated (sorry for this )in a comment on youtube, so probably the meter was ahead of it's time when it was developed / presented. 

Check the specs for the first model of the 87V ... they are the same  in terms of temperature and humidity ranges

I'm more convinced now that condensation on the board likely made the 189 go out of spec... the "Leads or Fuse error" should only ever occur with the dial in the amps measurement position.  Plugging a lead into the amps jack while in the voltage measurement causes a "Leads error" without the "of Fuse," so some kind of current leak around the dial wipers probably occurred.   

Title: Re: Handheld meter electrical robustness testing.
Post by: windsmurf on June 22, 2019, 11:06:02 pm
I'm more convinced now that condensation on the board likely made the 189 go out of spec... the "Leads or Fuse error" should only ever occur with the dial in the amps measurement position.  Plugging a lead into the amps jack while in the voltage measurement causes a "Leads error" without the "of Fuse," so some kind of current leak around the dial wipers probably occurred.

Thank you Joe for the new part 2 video with humidity enclosure and test, and pointing out it was a "Leads" error, indicating it detected a lead inserted in the amps jack, and not a "Leads or Fuse" error which should only happen with the dial in the amps section.   

So humidity probably did affect the meter in the 1st test with the jacks getting condensation and shorting the sensor.  Still not sure if it was the thermal differential or condensation that caused it to go out of spec in the 1st video but my hunch is, condensation played a role.  The 2nd test seemed to stay in spec enclosed in the ziplock... doing a resistance test which intuitively would be affected to a greater extent by condensation on the board.

I've seen some 87's and 189's input sensor malfunction due to moisture, or fail due to corrosion or debris/gunk between the board and the input jack assembly so that seems to be a weak spot of Flukes where moisture can get trapped.
 


Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on June 24, 2019, 01:28:34 am
No problem.  Its one of those things that we could all guess and be fairly confident that it was moisture causing it but it was easy enough to try this simple test. 

I doubt you would find many cases where people are trying to take measurements when the temperature is not stable.   Well, that is when you are looking for very small effects.   

One thing is certain and that is the box with the stacked peltiers will drive these meters with the camera to much lower temperatures than I could previously reach.  In the end, that was my goal. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2019, 12:07:46 pm
I doubt I will try and confirm this but if it's true, it's been a long time coming.   To be clear, Gossen has never contacted me about this meter beyond the original posts. 

If they have changed the design, it's too bad they didn't send me one.  I would have repeated all my tests on it, including running RF susceptibility ($$$+++).   They could have redeemed themselves, at least in my eyes.   

One thing it shows is that one competent EE with a tiny channel but with honest, detailed reviews can actually get a company like Gossen to make a change.   That's the only time, but I'll take it.   :-DD

https://www.youtube.com/watch?v=Jf_9XWL3TD8&lc=z225ulhytqmfe5jro04t1aokgym3ty4x4pxmdgdysnmlbk0h00410.1566905126264437 (https://www.youtube.com/watch?v=Jf_9XWL3TD8&lc=z225ulhytqmfe5jro04t1aokgym3ty4x4pxmdgdysnmlbk0h00410.1566905126264437)
Title: Re: Handheld meter electrical robustness testing.
Post by: MacMeter on August 27, 2019, 12:25:27 pm
I doubt I will try and confirm this but if it's true, it's been a long time coming.   To be clear, Gossen has never contacted me about this meter beyond the original posts. 

If they have changed the design, it's too bad they didn't send me one.  I would have repeated all my tests on it, including running RF susceptibility ($$$+++).   They could have redeemed themselves, at least in my eyes.   

One thing it shows is that one competent EE with a tiny channel but with honest, detailed reviews can actually get a company like Gossen to make a change.   That's the only time, but I'll take it.   :-DD

https://www.youtube.com/watch?v=Jf_9XWL3TD8&lc=z225ulhytqmfe5jro04t1aokgym3ty4x4pxmdgdysnmlbk0h00410.1566905126264437 (https://www.youtube.com/watch?v=Jf_9XWL3TD8&lc=z225ulhytqmfe5jro04t1aokgym3ty4x4pxmdgdysnmlbk0h00410.1566905126264437)

Of course they won’t send you a revised meter, they don’t want you to find any more issues!
GREAT job, watched the old video again, amazing amount of custom work as well as testing and of course your own, unpaid time and labor. But in the end.... CONGRATULATIONS on getting a bit of satisfaction.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 27, 2019, 11:21:50 pm
If they used NETIC as claimed, and basically replicated my changes, it's hard to believe I would have found anymore problems.   Then again, had they sent me one, I may have ran the 50,000 life cycle test on the rotary switch.  It would have been the first time I running one with a shutter.   So maybe your right.   

Maybe one day we may see another company as confident as Brymen is with their products.   Confidence comes from testing and with the high end Gossen being released with such blatant problems, maybe they just don't do a lot of testing.    Hard to say.  Hope they made the changes.  Hope the relays no longer change states with a simple hanger next to them.   Hope we saved someones life. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on August 28, 2019, 01:31:46 pm
If the assertion it true, it took them 1-1/2 years to silently release the fix. taking into account the change in manufacturing and compliance tests, I feel this took a bit longer than expected, but oh well. 

My suspicion is similar to yours: they buried their head on the sand until one of their big customers that did not suffer from "Joe derangement syndrome" reported the same issue.  :-DD

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on August 28, 2019, 04:53:30 pm
The last time I wrote them directly, the German office sent me back to the US distributor.   After the way the distributors behaved, I see no reason to go down that path again.   You want to talk about a total lack of integrity.   

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1221413/#msg1221413 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1221413/#msg1221413)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on October 31, 2019, 11:38:31 pm
It's been over two years since I first looked at the 121GW prototype.   UEI has had plenty of time to iron out any problems / shortcomings with the meter.   There's a lot to cover so expect a series of videos.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 01, 2019, 12:44:11 am
It's been over two years since I first looked at the 121GW prototype.   UEI has had plenty of time to iron out any problems / shortcomings with the meter.   There's a lot to cover so expect a series of videos.
You are baaaaaack! Nice!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 04, 2019, 03:12:38 am
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   

https://www.youtube.com/watch?v=wR1dHQsFBeM (https://www.youtube.com/watch?v=wR1dHQsFBeM)
Title: Re: Handheld meter electrical robustness testing.
Post by: okurka on November 04, 2019, 06:59:25 pm
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Where did you buy those from and when?

They still have the old firmware.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 05, 2019, 12:53:11 am
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Where did you buy those from and when?

They still have the old firmware.
These were purchased from the EEVBlog store about a week ago.

I think all the 121GW followers are aware that 1.57 is not the latest firmware but personally, I think the real question is why they are continuing to ship with the old firmware.   I understand that it can be updated but it's a handheld meter, not a PC.  If the changes truly do provide a significant improvement without introducing major problems, I would have expected it to be preloaded.   

That said, the goal of this first part was to perform a basic functional test of the hardware to make sure its in working order.   I will more than likely dedicate a full segment to the firmware alone.   For now, I plan to stay focused on the hardware. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Mr.B on November 05, 2019, 01:08:36 am
Bookmarked to follow the 121GW series.
Thanks Joe.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 05, 2019, 10:12:51 am
The 121GW Production DMM,  Part 1, Initial checkout and tear down   

They are hardly out of the box and already there are a few unexpected surprises.   


Where did you buy those from and when?

They still have the old firmware.
These were purchased from the EEVBlog store about a week ago.

I think all the 121GW followers are aware that 1.57 is not the latest firmware but personally, I think the real question is why they are continuing to ship with the old firmware.   I understand that it can be updated but it's a handheld meter, not a PC.  If the changes truly do provide a significant improvement without introducing major problems, I would have expected it to be preloaded..
In my experience it is very difficult to update the firmware in units ready to ship, as the repackaging process can be intricate if there are sealed plastic enclosures, etc.

But I also agree the firmware shouldn't affect so much the functionality flaws seen on the video. The slow auto range is something really obnoxious and, if this is not hardwired on the chipset, it could potentially be improved by different firmware. The inaccurate measurements are more concerning, though.

Unless the firmware update addresses these two issues, I am from the school of thought that, if it is working, don't update.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 05, 2019, 11:13:03 am
Hi there
It was weird how one of the units was glitching, measurement of the 1MOhm resistor. Does it glitches when you turn the rotary switch slow ( if you have re-assembled it) ? Will you try with and without the padding disk to see if has any difference?

Another question does the fw implements debounce for the contacts? 

Thanks for the video.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 05, 2019, 01:22:02 pm
In my experience it is very difficult to update the firmware in units ready to ship, as the repackaging process can be intricate if there are sealed plastic enclosures, etc.

But I also agree the firmware shouldn't affect so much the functionality flaws seen on the video. The slow auto range is something really obnoxious and, if this is not hardwired on the chipset, it could potentially be improved by different firmware. The inaccurate measurements are more concerning, though.

Unless the firmware update addresses these two issues, I am from the school of thought that, if it is working, don't update.

If you followed my testing of the firmware, they were changing the filters on each new release.   The noise was getting really bad and the AC line rejection was suffering.   I made a few videos showing the effects.    Because I was running all of these tests on the prototype and Dave appeared to be getting frustrated with the amount of information I was posting, I cleared out most of that information to avoid any confusion.    Of course, now we no longer have that problem as these two meters being brand new had better represent the current production.   

I assume the changes to the filters was made in attempt to reduce the settling time but it was making the meter worthless.  I want a fast and accurate meter.  If I have to choose between fast and inaccurate  or  slow and accurate,  hands down I will take accurate every time.   

It appears I gave up testing the firmware at 1.57 so it will be interesting to see how it has changed.   

If you think reprogramming the firmware takes a lot of time, stay tuned for part 2 where I look at the hardware.   The boards have some interesting rework which I dare say required a lot more time than it would take to install the latest firmware.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 05, 2019, 05:51:14 pm
Thanks for the insights.

If you followed my testing of the firmware, they were changing the filters on each new release.
No, I haven't. Not having the meter my interest flows somewhere else.

The noise was getting really bad and the AC line rejection was suffering.
There's no free lunch. :)

I assume the changes to the filters was made in attempt to reduce the settling time but it was making the meter worthless.  I want a fast and accurate meter.  If I have to choose between fast and inaccurate  or  slow and accurate,  hands down I will take accurate every time.
You can tell that Keysight thinks exactly like you when they designed the U1282A. I only wish they had put the resolution selection on a simple button press like the 87V. It is an excellent meter but &%$@! slow in 4-1/2 mode.

If you think reprogramming the firmware takes a lot of time, stay tuned for part 2 where I look at the hardware.   The boards have some interesting rework which I dare say required a lot more time than it would take to install the latest firmware.
Interesting, although hardware rework was probably done before packaging.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 06, 2019, 12:39:42 am
Thanks for the insights.

If you followed my testing of the firmware, they were changing the filters on each new release.
No, I haven't. Not having the meter my interest flows somewhere else.

You're going to be very bored with this series then.   Not that my data dumps are all that exciting to begin with.   :-DD

The noise was getting really bad and the AC line rejection was suffering.
There's no free lunch. :)

Maybe they found a way to have their cake and eat it too but from the trend I was seeing, that didn't seem to be the case.    Before installing the new firmware, I plan to repeat some of those noise tests using the older firmware with the new meter and see if the results repeat. 

I assume the changes to the filters was made in attempt to reduce the settling time but it was making the meter worthless.  I want a fast and accurate meter.  If I have to choose between fast and inaccurate  or  slow and accurate,  hands down I will take accurate every time.
You can tell that Keysight thinks exactly like you when they designed the U1282A. I only wish they had put the resolution selection on a simple button press like the 87V. It is an excellent meter but &%$@! slow in 4-1/2 mode.

If noise isn't a problem and you really only need a fast 3.5 digit DMM, I understand Harbor Freight still provides free ones.  :-DD  It will be interesting to see how it plays out. 

If you think reprogramming the firmware takes a lot of time, stay tuned for part 2 where I look at the hardware.   The boards have some interesting rework which I dare say required a lot more time than it would take to install the latest firmware.
Interesting, although hardware rework was probably done before packaging.

If you watched the video, you know the one box had been opened to add the fuses.  As you don't have a meter to try it, you could use Dave's numbers.   

How accessible is it ? I thought it was behind the screwed-down fuse cover.

It is.
It takes less than 20 seconds to remove the holster, undo two screws (metal threaded insert), remove the battery cover and take out the SD card.
Yes, I timed it.
Hardly a chore for anyone who wants to do occasional data logging. And as I said, faster than dicking around with Bluetooth BLE and a ridiculously slow data rate.

If you are doing data logging all the time, I'd recommend buying a proper data logger with the convenient interface of your choice.

What's interesting about his comment is once I had LabView working with the meter,  I never used the SD card to log again.  My only real dicking around was getting my software working.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 10, 2019, 08:08:49 pm
Part 2, looking at the differences between the prototype and production hardware.   I seem to have missed FB4.

https://www.youtube.com/watch?v=Ayd9Lz9xZXQ&feature=youtu.be (https://www.youtube.com/watch?v=Ayd9Lz9xZXQ&feature=youtu.be)
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on November 10, 2019, 08:48:09 pm
Riveting watching as always Joe.  :clap:
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 10, 2019, 09:44:45 pm
Good to watch the collected differences. That SD Holder card really needed some reinforcement, a little blob of glue as said in the video.

What about the glitch on the rotary switch? Gone?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2019, 01:10:41 am
Fuck me! 

Looking at the changes on the Rev V.02 units, its obvious they have upped their game.   So I just spent $600+ on old stock that I will pretty much bet is not going to survive to the same levels this new meter will.   Look at the size of those transistors compared with the parts in mine.   

I opened up the second meter just to make sure as it was a later SN.  No luck,  the two meters that were shipped are both the old design.   

So I've burned down a fair bit of time, plus the cash.   I am going to have to give it some thought on how to proceed.   
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on November 11, 2019, 08:00:56 am
The latest is V.02.1910 which has the transistors integrated. Although they are not in the wild yet.
Title: Re: Handheld meter electrical robustness testing.
Post by: kf4hzu on November 11, 2019, 10:28:47 am
Do these changes only impact input protection?
Title: Re: Handheld meter electrical robustness testing.
Post by: exe on November 11, 2019, 10:56:39 am
It would be cool to know the differences between revisions and what they mean to user. So, I really appreciate what Joe does.

I wonder if it's possible to improve some parameters (at least in some ranges) by fine-tuning components. May be it's time for me to remove the dust from my DMM and read the datasheet...

PS Afaik Dave said "we are not going to spin a different pcb revision, we'll fix problems in software". Turned out either my memory is bad, or they changed their mind.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 11, 2019, 10:57:43 am
Do these changes only impact input protection?

Hope in the positive way to protect more that input.
Title: Re: Handheld meter electrical robustness testing.
Post by: Dr. Frank on November 11, 2019, 11:57:50 am
Fuck me! 

Looking at the changes on the Rev V.02 units, its obvious they have upped their game.   So I just spent $600+ on old stock that I will pretty much bet is not going to survive to the same levels this new meter will.   Look at the size of those transistors compared with the parts in mine.   

I opened up the second meter just to make sure as it was a later SN.  No luck,  the two meters that were shipped are both the old design.   

So I've burned down a fair bit of time, plus the cash.   I am going to have to give it some thought on how to proceed.


Hey Joe!

This transistor clamping circuit on the additional PCB is obviously the circuit, which Dave had explained in his videos #1157 and 1158.

I criticized though, that this does not work at all to protect the pin15 of MUX 4053, U9 for the Ohm circuit.

https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043757/#msg2043757 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043757/#msg2043757)

The circuit is able to protect symmetrical inputs, at +/- 6V clamp voltage, or +/- 20..25V, if special npn types are used.

This use case is asymmetric, as it has to be protected at -0.5V / + VDD ~ 4...16V.

I've never got a response from Dave, but obviously this not working circuit was implemented in certain HW versions of the 121GW.
It would be interesting, if in the most recent version, the BC diode of both transistors were properly used to protect the Ohm circuit, by using them as direct replacement of the original 1N4007.

Another remark: the use of the 1N4007, as well as a TVS at that point both affect negatively the calibration of the 5M and 50M Ohm ranges by their leakage currents. Only without them, these ranges may work linearly.

Frank
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2019, 01:08:16 pm
...
This transistor clamping circuit on the additional PCB is obviously the circuit, which Dave had explained in his videos #1157 and 1158.
...
Another remark: the use of the 1N4007, as well as a TVS at that point both affect negatively the calibration of the 5M and 50M Ohm ranges by their leakage currents. Only without them, these ranges may work linearly.

Frank,  1158 shows the mezzanine boards that are used on the ones I just purchased.   These are not the same parts that are used on the current revision, nor is it the same PCB. 

I remember your posts about the leakage.  I've never ran any experiments as I didn't think it would be helpful to run on the prototype with the other changes I had made but would not be at all surprised.   

I can't comment on how any of these changes effect the electrical robustness of the meter.  If I wanted to analyze the most recent revision, I would need a current schematic for starts.  Still, like the UT181A, the has a decent front end design, the layout needs some help.  That's why I run the tests. 

PS Afaik Dave said "we are not going to spin a different pcb revision, we'll fix problems in software". Turned out either my memory is bad, or they changed their mind.

I just paid for two brand new meters and received the floor sweepings that are now apparently 2 PCB revisions old.   I wasn't told anything about them being old stock when I made the purchase or I wouldn't have placed the order.   I got fucked once.  It won't happen again. 

I seem to remember Dave posting something to that effect.  Searching, here is one about the the switch.  The brand new, out of the box meter certainly had some intermittent problem. 
https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/msg1405035/#msg1405035 (https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/msg1405035/#msg1405035)

I wasn't able to find those posts about the revision and firmware.     

As far as how to proceed.  We have two old meters that do not represent the current production.   Sure I can test them but like the prototype, if they do poorly, the response will be we addressed that in the new revision.   

I can't see wasting too much time on the details.  For example, Frank mentions the non-linearity.  The new meter will behave differently.

If the new design addresses the shim, cycling the switch may not prove useful.   Then again, I am up to seeing how it holds up without spit shinning the contacts.  It could prove entertaining but keep in mind that the fall back is always going to be, we addressed that in the next revision. 

I still plan to keep the one meter as a virgin, if anything just for a reminder of business practices.   As for the second meter, feel free to comment on what you would like to see done with it.   I'm not at all apposed to just saying fuck all and run the transient tests to failure and cycling the switch just for the entertainment.   
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on November 11, 2019, 01:42:30 pm
While I'd be interested in seeing every single version tested and compared, it doesn't really matter that much and is obviously impractical for a hobbyist to do so. Who knows how many more board revisions there will be in the future. In my mind, it's still the current version if that is what is being sold.
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 11, 2019, 03:03:04 pm
The latest is V.02.1910 which has the transistors integrated. Although they are not in the wild yet.

Will this PCB have the 'correct' thickness so no shim is needed?
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 11, 2019, 03:12:53 pm
Fuck me! 

Looking at the changes on the Rev V.02 units, its obvious they have upped their game.   So I just spent $600+ on old stock that I will pretty much bet is not going to survive to the same levels this new meter will.   Look at the size of those transistors compared with the parts in mine.   

I opened up the second meter just to make sure as it was a later SN.  No luck,  the two meters that were shipped are both the old design.   

So I've burned down a fair bit of time, plus the cash.   I am going to have to give it some thought on how to proceed.


Hey Joe!

This transistor clamping circuit on the additional PCB is obviously the circuit, which Dave had explained in his videos #1157 and 1158.

I criticized though, that this does not work at all to protect the pin15 of MUX 4053, U9 for the Ohm circuit.

https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043757/#msg2043757 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043757/#msg2043757)

The circuit is able to protect symmetrical inputs, at +/- 6V clamp voltage, or +/- 20..25V, if special npn types are used.

This use case is asymmetric, as it has to be protected at -0.5V / + VDD ~ 4...16V.

I've never got a response from Dave, but obviously this not working circuit was implemented in certain HW versions of the 121GW.
It would be interesting, if in the most recent version, the BC diode of both transistors were properly used to protect the Ohm circuit, by using them as direct replacement of the original 1N4007.

Another remark: the use of the 1N4007, as well as a TVS at that point both affect negatively the calibration of the 5M and 50M Ohm ranges by their leakage currents. Only without them, these ranges may work linearly.

Frank

From what I can tell from the pictures they now seem to be using two STN83003

https://www.st.com/resource/en/datasheet/stn83003.pdf (https://www.st.com/resource/en/datasheet/stn83003.pdf)

has a Emitter-base breakdown voltage 14V to 18V.

Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 11, 2019, 03:15:50 pm
I just paid for two brand new meters and received the floor sweepings that are now apparently 2 PCB revisions old.   I wasn't told anything about them being old stock when I made the purchase or I wouldn't have placed the order.   I got fucked once.  It won't happen again. 

I am sorry to hear you got caught on the crossfire of revisions. I was looking forward for that series but, yes, I agree with you that your regular tests will not be greatly useful at this point in time. Perhaps get ahold of a modern schematics and try to implement in the new meter, à la UT61E improved protection exercise?

If only the revisions had an externally visible marker... Instead, cue the serial number merry-go-round. I wonder if UEI was avoiding an Osborne effect? If so, the cat is out of the hat. (but I confess I wasn't following the evolution that close anyways to know if this is old news).

Although any manufacturer states that "the products are subject to changes without prior notice", this reeks of a Uni-T UT61E stunt.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 11, 2019, 06:16:57 pm
While I'd be interested in seeing every single version tested and compared, it doesn't really matter that much and is obviously impractical for a hobbyist to do so. Who knows how many more board revisions there will be in the future. In my mind, it's still the current version if that is what is being sold.

It appears they have been selling the newer revision for at least a few months but Dave is holding onto old stock.   You would think UEI would want that old stock replaced. 

From my testing with the prototype, besides the mechanical problems, this is the weakest link.   As I mentioned in that last video, I wouldn't hang my hat on the fact that the prototype 121GW withstood levels beyond what an 87V that obviously had a problem. 

Of course Dave/UEI and the internet masses may suggest these changes make no difference but people like me will ask why they continue to focus on that section of circuitry.   


I just paid for two brand new meters and received the floor sweepings that are now apparently 2 PCB revisions old.   I wasn't told anything about them being old stock when I made the purchase or I wouldn't have placed the order.   I got fucked once.  It won't happen again. 

I am sorry to hear you got caught on the crossfire of revisions. I was looking forward for that series but, yes, I agree with you that your regular tests will not be greatly useful at this point in time. Perhaps get ahold of a modern schematics and try to implement in the new meter, à la UT61E improved protection exercise?

If only the revisions had an externally visible marker... Instead, cue the serial number merry-go-round. I wonder if UEI was avoiding an Osborne effect? If so, the cat is out of the hat. (but I confess I wasn't following the evolution that close anyways to know if this is old news).

Although any manufacturer states that "the products are subject to changes without prior notice", this reeks of a Uni-T UT61E stunt.

I have no doubt that I could modify the production meter to survive but I think that takes us even further from meaningful data.   The best thing would be to get an actual meter.   I can't see this happening.  It seems we have a jumbled up grab bag of meters.  Like a child, blindly reaching into a grab bag of candy,  you pull something out.  It's not such a great business practice.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 15, 2019, 01:13:22 am
A few updates.   First, it appears that the new hardware does not require the shim.   I've asked the person posting if they could measure the PCB thickness and will post any updates as they become available. 

Dave did offer to refund the cost of the meters, including shipping.  There was no discussion about replacing them with the latest hardware.   I declined the offer and plan to move forward using the old revision.   There are a couple of reasons for this.  First, I have a fair amount of time already invested in the old hardware.  I also suspect that the vast majority of owners don't have the latest revision.   It sounds like many of the meters sold were even older hardware.    These two meters may be a better representation of what the viewers own.   

As I have stated, if any problems are uncovered during these tests I suspect the fallback plan will be to claim it was addressed on the next revision.  When I looked at the prototype that Dave supplied, it caused a fair amount of confusion with viewers.   I expect nothing less when running these meters.   While the whole revision problem could have been avoided, it isn't really my concern this time around.   

For those of you who have offered to help cover the costs, I just wanted to say again that I appreciate the gesture. 


Frank,
About your comment,  "I criticized though, that this does not work at all to protect the pin15 of MUX 4053, U9 for the Ohm circuit."   I felt you (and possibly others) may have been a little confused.   I doubt I will make any changes to the hardware this time around.  With the prototype, I had added two clamps in an attempt to protect the mux.  If you watched the videos, may have noticed the TVS located across the supply of the mux (located on top of D7&D8).     There was a second clamp that was located upstream from the resistor R82 but after the selector switch on node R_RLD.   This first clamp acts like every other higher end meter I have looked at.  It can withstand enough energy to overcome the PTCs thermal time constant.   The PTC (PTC3) along with the surge resistor (R16) limit the current through the first stage clamp.   The small resistor (R82) further limits the current.     Again, the schematics are not up to date and I really didn't dig into how these meters are designed. 

None of this is anything new as I went over it back in 2017 when I made the first series of videos for the prototype.     

I suspect that the first stage clamp was enough to protect the mux but I never tested it.  At the time my goal wasn't to optimize a production solution.  That's UEI's job and that's assuming that they even wanted to try and improve it.   Anyway, my point was that the meter may very well survive (my tests) without D7 & D8 present. 

Hope that helps. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Dr. Frank on November 15, 2019, 07:58:36 am
Hello Joe,


Frank,
About your comment,  "I criticized though, that this does not work at all to protect the pin15 of MUX 4053, U9 for the Ohm circuit."   I felt you (and possibly others) may have been a little confused. 

I don't think at all, that I'm confused.
This critic is related to Daves videos #1157, especially 1158, not to any of your videos.
There, Dave clearly shows this dual transistor clamp to replace the former 1N4007, which will not work to protect the MUX.
You might investigate on that issue, simply by applying an additional voltage across the resistor under test, first higher than the supply voltage of the MUX, 2nd a negative one, and then simply checking that the voltage on this MUX pin really exceeds the Absolute Max. Ratings.

I doubt I will make any changes to the hardware this time around.  With the prototype, I had added two clamps in an attempt to protect the mux.  If you watched the videos, may have noticed the TVS located across the supply of the mux (located on top of D7&D8).     There was a second clamp that was located upstream from the resistor R82 but after the selector switch on node R_RLD.   This first clamp acts like every other higher end meter I have looked at.  It can withstand enough energy to overcome the PTCs thermal time constant.   The PTC (PTC3) along with the surge resistor (R16) limit the current through the first stage clamp.   The small resistor (R82) further limits the current.     Again, the schematics are not up to date and I really didn't dig into how these meters are designed. 

None of this is anything new as I went over it back in 2017 when I made the first series of videos for the prototype.     

I suspect that the first stage clamp was enough to protect the mux but I never tested it.  At the time my goal wasn't to optimize a production solution.  That's UEI's job and that's assuming that they even wanted to try and improve it.   Anyway, my point was that the meter may very well survive (my tests) without D7 & D8 present. 

Hope that helps.

I also do not expect that you change the actual circuit, simply check what Dave has really implemented there.. as the latest revisions have some totally different transistors, and maybe a different circuit, all that already indicates, that this version you have on your table, did not work as intended.

I expect, that the DMM will fail, when you only run your usual (destructive) tests.

Frank
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 15, 2019, 12:52:45 pm
Hello Joe,


Frank,
About your comment,  "I criticized though, that this does not work at all to protect the pin15 of MUX 4053, U9 for the Ohm circuit."   I felt you (and possibly others) may have been a little confused. 

I don't think at all, that I'm confused.
This critic is related to Daves videos #1157, especially 1158, not to any of your videos.

I was assuming that your comment stemmed from watching my recent video where I was talking about my clamps.  I didn't watch the two videos you mention other than seeing they were on the typical back to back clamp.   From your comment, it seems Dave was suggesting that this type of clamp, on it's own was going to improve the meters electrical robustness.   I wouldn't be at all surprised to see this version of hardware fail at an even lower level than the prototype using the 2X 4007s if this was the only change that was made.   

I also do not expect that you change the actual circuit, simply check what Dave has really implemented there.. as the latest revisions have some totally different transistors, and maybe a different circuit, all that already indicates, that this version you have on your table, did not work as intended.

I expect, that the DMM will fail, when you only run your usual (destructive) tests.

Frank

Assuming the mezzanine board is actually a back to back transistor clamp,  I really don't understand the purpose.   I am assuming that they have a similar clamp on R_RLD to handle the transient part.  If this is not there, I don't think there is much investigation to do outside of looking at the circuit board for additional clamps and to verify the mezzanine boards circuit.  Beyond that, I think we all know the outcome if we start to exceed the manufactures absolute ratings.   :-DD   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 15, 2019, 04:33:19 pm
Frank,
I watched the two videos you mentioned.  The most interesting part was seeing an old HP1704 scope as I think I had to use that same model in my early days.  In #1157, 7:00 Dave does mention the 121GW.  Really at 11:10 is where he starts to talk about the protection and replacing the diodes.    In #1158, at 7:30 its mentioned.   He never dives into great detail about their goals for the change or the problems they are trying to solve.  They also make no mention of additional changes.

I also read through the thread you linked:
https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043757/#msg2043757 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043757/#msg2043757)

You have the new clamp referenced to the HY3131 AGND (also the TRMS ref) rather than to VSS of U9 which is where I assume they have actually connected the new clamp.  Not that it makes a difference as I believe your point is still valid.   I changed your drawing to show the paths of the couple of mods we are talking about on the prototype.  The primary clamp returns right to the common (GND) input of the DMM.  Between this, R16 and PTC3, this is where most of the energy is dissipated.   Nothing unusual as this seems to be the accepted practice for the more robust meters I have looked at.   Of course I did change out the HEF for the TI part as well.    I really didn't spend much time as I was really wanting to know what the next weakest link was going to be,  so I took a sledge hammer to the finishing nail and moved  on.   

If their goal is only to reduce the leakage, just remove D7/8 and get on with it.  But if their goal is to have the meter survive to something like that low end  AMPROBE AM510 I looked at years ago, then they will need to somehow protect that Mux and maybe implement a few other changes we talked about back in 2017.   After watching the videos and reading the thread, I am not hopeful that we are going to see any gains in the meters robustness.   



As a side note,  I did receive a new message from Dave offering to replace the meters with the more current design.  I have declined this offer as well for the reasons I mentioned earlier.   If we run into a major problem that Dave knows was addressed in newer versions of the hardware,  I just suggested he chime in.    Considering the confusion surrounding the prototype,  I am sure with all of these new variants we are going to see a lot more confusion.   While it seemed fair to pull most of the videos on the prototype to avoid this and not to cause undo harm to the reputation of the product or people involved, now that the meter is in production and these were purchased through the normal channels, I see no reason to be overly concerned about it. 

So stay tuned.  I've started to work on part 3 where I plan to start comparing the 121 with some other meters I have available.   
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on November 16, 2019, 12:20:21 am
As a side note,  I did receive a new message from Dave offering to replace the meters with the more current design.  I have declined this offer as well for the reasons I mentioned earlier.   If we run into a major problem that Dave knows was addressed in newer versions of the hardware,  I just suggested he chime in.

Sorry to hear you don't want to swap for the new meters, but your choice.
Bad luck timing on your part, had you asked before ordering I could have said hold off for a few weeks and I'll send you the new build.

As for the new build, FYI, it as the larger transistors integrated, a 1.60mm (measured) PCB, no shim, a plated rotary switch hole (can see this in the photo I posted), and the battery spring contacts are shorter.
Again, the new design has undergone full independent ETL testing.

Quote
Considering the confusion surrounding the prototype

There was not supposed to be any confusion surrounding the prototype, I sent it to you with the specific instructions not to do any testing with it, it was just for fun to blow up.
But you went and made a whole serious of videos about it that had confused a lot of people.

[attachimg=1]
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 16, 2019, 01:04:19 am
I waited two years and you sent me old stock.  That's on you.   If you wanted to see the latest hardware reviewed,  there's an easy fix.  I would still run the old hardware but at least if there was an improvement, viewers could see it first hand.   

I've been running controlled tests on meters from the beginning.  I've never had the ability to blow up a meter.  20 Joules isn't much.   Maybe that was your perception of what I was doing but it's always been about bench marking the meters.         

To be clear, I have no problem with the time I spent looking at the prototype but that's in the past.   However, I learned a fair bit about the meter when running those tests which should help in the upcoming reviews on this older hardware.   It will be very interesting to see how it holds up after two years of development.   Should do fine, right??
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on November 16, 2019, 01:12:02 am
But I also agree the firmware shouldn't affect so much the functionality flaws seen on the video. The slow auto range is something really obnoxious and, if this is not hardwired on the chipset, it could potentially be improved by different firmware.

Autoranging speed:

https://www.youtube.com/watch?v=izCDWjK_pV4 (https://www.youtube.com/watch?v=izCDWjK_pV4)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on November 16, 2019, 01:19:07 am
I waited two years and you sent me old stock.  That's on you. 

Fine. But like I said in my email if you had asked first I would have told you to hold off for a couple of weeks and I could have sent the new build that was on the way.
I do not usually pack and ship, so I had no idea you ordered these meters. If I had noticed I would have known what you had wanted them for and would have contacted you.
I can't help bad luck timing and lack of communication.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 16, 2019, 01:21:50 am
Looks like she was drifting down.  Don't include the settling time.  :-DD  Even more funny was seeing that slow Keysight lock right in and hold steady.   

BM869s, you loss a digit, of course it's a bit faster.   BM235 you loose 2 digits, and like magic its even faster.

I plan to spend a segment just on the firmware.   I'm really interested in seeing how they have changed their filters. 
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on November 16, 2019, 01:27:26 am
Looks like she was drifting down.  Don't include the settling time.  :-DD  Even more funny was seeing that slow Keysight lock right in and hold steady.   

Err, the Keysight displayed 9.7ohms at one point.
As for "drift" in the 1mOhm LSD, it's a switch, just my finger pressure can change by that amount. I checked, the Keysight "drifts" in a similar way, you just didn't happen to see it in the video.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 16, 2019, 01:37:25 am
I waited two years and you sent me old stock.  That's on you. 

Fine. But like I said in my email if you had asked first I would have told you to hold off for a couple of weeks and I could have sent the new build that was on the way.
I do not usually pack and ship, so I had no idea you ordered these meters. If I had noticed I would have known what you had wanted them for and would have contacted you.
I can't help bad luck timing and lack of communication.

If I was looking for preferential treatment, I would have contacted you.  To be clear, I wasn't.  Buying the meters, dealing with service,.... it's all part of the process.   I want the same hardware that anyone else placing an order is going to get.   If you are concerned about selling old hardware, don't sell old hardware.   If you are concerned that there is a problem with people placing orders not understanding what it is you are selling, then explain it on your ad.  Don't expect customers to reach out to you to try and sort it out. 

Again, if you feel running the latest hardware would help viewers in some way,  I would be willing to run it as part of these tests.   It's up to you.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 16, 2019, 01:41:28 am
Looks like she was drifting down.  Don't include the settling time.  :-DD  Even more funny was seeing that slow Keysight lock right in and hold steady.   

Err, the Keysight displayed 9.7ohms at one point.
As for "drift" in the 1mOhm LSD, it's a switch, just my finger pressure can change by that amount. I checked, the Keysight "drifts" in a similar way, you just didn't happen to see it in the video.

The only one moving was the 121 from what I saw.  If the others drift the same and you didn't include it in the video, that's easy to fix.  We are all about the data.   Your finger was on that button a long time with the Keysight showing out 3 places and that thing was solid.   I was thinking they may do some sort of filter change, like Brymen.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 16, 2019, 01:57:01 am
Looks like she was drifting down.  Don't include the settling time.  :-DD  Even more funny was seeing that slow Keysight lock right in and hold steady.   

Err, the Keysight displayed 9.7ohms at one point.
As for "drift" in the 1mOhm LSD, it's a switch, just my finger pressure can change by that amount. I checked, the Keysight "drifts" in a similar way, you just didn't happen to see it in the video.
Thanks for sharing the video; I can attest the Keysights drift some as well and I even commited that sin when I did my own video about the subject, although the U1273A was still using Keysight's evil smooth filter mode that crapped out everything on it (it became better after disabling it).

https://www.youtube.com/watch?v=EWZ0OSjYnvg (https://www.youtube.com/watch?v=EWZ0OSjYnvg)
Title: Re: Handheld meter electrical robustness testing.
Post by: gnavigator1007 on November 16, 2019, 03:46:37 am

There was not supposed to be any confusion surrounding the prototype

There's still confusion about this meter. See people regularly thinking it's open source. Remember seeing contradictory instructions on which way to install the shim. Various things like this. From what I've seen, joeqsmith has made plenty of effort to make clear that the original was a prototype meter. Suspect more of the confusion has come from people watching videos out of order, reading parts of old forum discussion, and maybe previous episodes of the amp hour. There's various info scattered across so many places. Now with these board revisions I'd expect even more confusion to come. While I'd love to see joeqsmith run all his tests on the meters he currently has as well as the very latest, I'd also hope that you'll do a video explaining the latest changes and why they were made.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on November 17, 2019, 12:36:38 am
Looks like she was drifting down.  Don't include the settling time.  :-DD  Even more funny was seeing that slow Keysight lock right in and hold steady.   

Err, the Keysight displayed 9.7ohms at one point.
As for "drift" in the 1mOhm LSD, it's a switch, just my finger pressure can change by that amount. I checked, the Keysight "drifts" in a similar way, you just didn't happen to see it in the video.
Thanks for sharing the video; I can attest the Keysights drift some as well and I even commited that sin when I did my own video about the subject, although the U1273A was still using Keysight's evil smooth filter mode that crapped out everything on it (it became better after disabling it).

https://www.youtube.com/watch?v=EWZ0OSjYnvg (https://www.youtube.com/watch?v=EWZ0OSjYnvg)

Thanks for the testing video.
The U1282A looks to be the slowest but gets to the value , minus one digit, maybe can confirm the same behaviour for that meter. Looks like the ut136b is fast and accurate but doesn't have much digits to process. Would go for the slow , but hi resolution and accurate than fast and inacurate.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 03:10:41 am
Going over my notes for the prototype to sort out what tests I plan to run.   One of the problems I came across was with the VA mode.  Roger, who ran the YT channel  KainkaLabs, repeated my tests.   He did a really nice job explaining the problem and how to work around it.   I doubt I will go over this problem again, so if you're interested, I suggest you watch his video.

https://www.youtube.com/watch?v=FNsPr1OEq7c (https://www.youtube.com/watch?v=FNsPr1OEq7c)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 03:24:32 am
In part 3 we compare the old production hardware with some of the other surviving meters.   We attempt to measure a small capacitor, low voltages and currents.   Because I know Dr Frank like those really small signals, I drove it into the muck.   The tape eraser is brought out to see if the production meters are less sensitive to it.  Finally we finish up with some higher voltage tests and install the latest firmware, because I heard that it fixes everything.     

https://www.youtube.com/watch?v=7AhypTCJOTE (https://www.youtube.com/watch?v=7AhypTCJOTE)

There's a lot of testing to go so stay tuned for part 4.
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 17, 2019, 12:56:22 pm
Thanks for the video Joe, interesting as always, and thank you for continuing testing with your "new" 121gw's.

And just a note, don' know if you mentioned this but your 1nF reference cap which you measured to 992pF with the BK Precision, the BNC adapter you then used probably added 8-10pF in parallel, so reference cap the other meters saw was likely very close to exactly 1nF. Just to show how accurate some of them really were.


Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 17, 2019, 01:35:19 pm
About the 121gw capacitance drifting, my (uneducated) guess is that it might have something to do with the SM6T22CA (D13 on the original 121 schematics), these devices seems to have a lot of nonlinear, voltage and probably temperature dependent capacitance behavior.

Perhaps a reason D13 now seems to been replaced with a traditional transistor clamp circuit in the latest hardware revision.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 02:52:40 pm
Thanks for the video Joe, interesting as always, and thank you for continuing testing with your "new" 121gw's.

And just a note, don' know if you mentioned this but your 1nF reference cap which you measured to 992pF with the BK Precision, the BNC adapter you then used probably added 8-10pF in parallel, so reference cap the other meters saw was likely very close to exactly 1nF. Just to show how accurate some of them really were.

You are correct.   FYI, all three Flukes measure 9pf for the jig by itself.   Added to the 992 measured with the BK,  1001pf read by the Flukes.   Funny how that works out.   :-DD :-DD   

Normally, for smaller values I will attach them to a test board and use the VNA which provides more detail.  The test fixture is the same PCBs used for the standards used to calibrate the VNA.   

About the 121gw capacitance drifting, my (uneducated) guess is that it might have something to do with the SM6T22CA (D13 on the original 121 schematics), these devices seems to have a lot of nonlinear, voltage and probably temperature dependent capacitance behavior.

Perhaps a reason D13 now seems to been replaced with a traditional transistor clamp circuit in the latest hardware revision.

It's very possible they have corrected it with the latest revision.   Someone would need to check it. 

I was surprised how they coerce the reading to zero if the meter is powered on with no rel but if you are fast enough to rel it out, it will start to read negative values.   Rel it after it have gone negative and it will again coerce to zero, no mater how far the meter continues to drift.  I call this a bug.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 17, 2019, 03:04:24 pm
I don't think it's D13 , that input is used for some functions like mV where the drift should be very noticeable .
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 17, 2019, 04:09:40 pm
I was surprised how they coerce the reading to zero if the meter is powered on with no rel but if you are fast enough to rel it out, it will start to read negative values.   Rel it after it have gone negative and it will again coerce to zero, no mater how far the meter continues to drift.  I call this a bug.

Yeah as I earlier wrote in the other thread if they only allowed for negative capacitance values this drift issue could be handled with the rel button. At least if you are quick enough to do the measurement and remember to recheck if it drifted further before the next measurement.

So what! if it then perhaps initially will read something like negative 50pF or whatever with no probes attached, if that is what they are concerned about...
 

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 05:22:01 pm
So what! if it then perhaps initially will read something like negative 50pF or whatever with no probes attached, if that is what they are concerned about...

Guessing they felt the negative capacitance would cause a bit of confusion and decided to coerce it to zero.  Lots of ways to skin this problem but what they have now isn't at all what I would have expected from a company who designs and produces DMMs. 
Title: Re: Handheld meter electrical robustness testing.
Post by: IanB on November 17, 2019, 05:40:39 pm
Guessing they felt the negative capacitance would cause a bit of confusion and decided to coerce it to zero.  Lots of ways to skin this problem but what they have now isn't at all what I would have expected from a company who designs and produces DMMs.

Do we know for sure that UEI "designs and produces DMMs"? For instance, do we know of other meters they make apart from the 121GW? I have the feeling their concerns lie elsewhere and the 121GW has been a bit of a departure from their normal product lines.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 17, 2019, 05:58:28 pm
The drift is not acceptable ... even for a chinese multimeter .
Positive offset is "normal" if you look at a Fluke ~60pF , but it would be possible for 121GW's microcontroller to zero this at startup - of course when the drift issue is resolved .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 06:25:48 pm
Guessing they felt the negative capacitance would cause a bit of confusion and decided to coerce it to zero.  Lots of ways to skin this problem but what they have now isn't at all what I would have expected from a company who designs and produces DMMs.

Do we know for sure that UEI "designs and produces DMMs"? For instance, do we know of other meters they make apart from the 121GW? I have the feeling their concerns lie elsewhere and the 121GW has been a bit of a departure from their normal product lines.

These would be good questions for Dave.   He did post that video on the history of the 121 but I haven't watched it.   You may find some of your answers there. 

There was an early discussion about UEI getting out of the DMM business.    With the data spread out, you may want to just try the advanced search and see what you can find.   


The drift is not acceptable ... even for a chinese multimeter .
Positive offset is "normal" if you look at a Fluke ~60pF , but it would be possible for 121GW's microcontroller to zero this at startup - of course when the drift issue is resolved .

First, to avoid any confusion, the attached data is taken from the prototype.  This is AFTER I had installed more recent firmware and had the BLE interface working.   This meter had been aligned by myself and is in no way in current calibration.   The meter had also been damaged a couple of times and I had implemented the changes I mentioned earlier with the clamps, different Mux, etc.   The prototype uses a different reference.  There may be other differences as well.

These graphs show the 121's internal temperature (obviously no longer correct) and measuring a 2nF capacitor over an 8 hour period.   What is interesting about this data is that we saw in the last segment how the old production meter drifted about 10pF in maybe 10 minutes.     At least with the prototype the drift appears to correlate with the reported temperature.  I would have expected old production hardware to also show an increase in capacitance, rather than the decrease.  But it does appear the two have similar slopes, just opposite in magnitude.   

At some point, I will toss the 121 into that meat packing box and we can get some idea how it behaves over temperature.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 17, 2019, 06:44:04 pm
I didn't said the drift is temperature related , in fact is highly unlikely because when you cycle through functions and back to cap , usually is reseted .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 07:16:00 pm
I didn't said the drift is temperature related , in fact is highly unlikely because when you cycle through functions and back to cap , usually is reseted .
No one suggested you did.  I am only presenting you with the data I collected off the prototype.  The prototype was one of the worst meters I had looked at for temperature drift.  It will be interesting to see this old production hardware compares.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 17, 2019, 09:13:49 pm
Do we know for sure that UEI "designs and produces DMMs"? For instance, do we know of other meters they make apart from the 121GW? I have the feeling their concerns lie elsewhere and the 121GW has been a bit of a departure from their normal product lines.
These would be good questions for Dave.   He did post that video on the history of the 121 but I haven't watched it.   You may find some of your answers there. 

There was an early discussion about UEI getting out of the DMM business.    With the data spread out, you may want to just try the advanced search and see what you can find.   
I've known UEI as a DMM manufacturer for quite some time. By the time the 121GW came about, they really had no meters on their lineup (all discontinued). They have now four meters, alongside a number of clamps and other measuring devices.

(...) measuring a 2nF capacitor over an 8 hour period.  
Unless the tests are done by measuring a capacitor for 10s at every minute, which reflects a more practical scenario, what is the point of this? Capacitance testing on a DMM is useful only for a quick check, especially around its lower edge.

At some point, I will toss the 121 into that meat packing box and we can get some idea how it behaves over temperature.
That is a much nicer test, especially since autumn is upon us! :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 17, 2019, 09:25:15 pm
(...) measuring a 2nF capacitor over an 8 hour period.  
Unless the tests are done by measuring a capacitor for 10s at every minute, which reflects a more practical scenario, what is the point of this? Capacitance testing on a DMM is useful only for a quick check, especially around its lower edge.

At some point, I will toss the 121 into that meat packing box and we can get some idea how it behaves over temperature.
That is a much nicer test, especially since autumn is upon us! :-+

That's been a long time ago but I suspect what drove it was me seeing that 121 proto moving all over and wanting to know if it would settle.   

After watching Dave's video,  I plan to have a look at the resistance stability in the 50 ohm range.   I put together a poor mans reference using a Vishay 0.005% 1ppm S-Series foil resistor.   I'm surprised the numbers the old 34401A throws up after an hour warm up are this close.  It's been a good meter. 

I plan to repeat the stopwatch test as well. 
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 17, 2019, 11:22:52 pm
Going over my notes for the prototype to sort out what tests I plan to run.   One of the problems I came across was with the VA mode.  Roger, who ran the YT channel  KainkaLabs, repeated my tests.   He did a really nice job explaining the problem and how to work around it.   I doubt I will go over this problem again, so if you're interested, I suggest you watch his video.

https://www.youtube.com/watch?v=FNsPr1OEq7c (https://www.youtube.com/watch?v=FNsPr1OEq7c)

That was a slick fix, Joe. :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 18, 2019, 12:58:32 am
Going over my notes for the prototype to sort out what tests I plan to run.   One of the problems I came across was with the VA mode.  Roger, who ran the YT channel  KainkaLabs, repeated my tests.   He did a really nice job explaining the problem and how to work around it.   I doubt I will go over this problem again, so if you're interested, I suggest you watch his video.

That was a slick fix, Joe. :-+

When I demo'ed that back in 2017, I caught some flack over it.   I was glad to see another person finally post a video on the VA mode and was even more pleased when he repeated my test.   I haven't downloaded the latest manual yet to see if they ever did anything with it.  You know the old saying  "you can't push a rope"? 

I made an attempt to repeat Dave's settling time test using roughly the same resistance value.   I've ran this same test before with the prototype and even older firmware.    The left 121GW old production hardware is using firmware 1.57, the right 2.02.   The counter is clocked at 1KHz.  MOSFET switches are used for controlling all three meters (can't have that switch resistance changing with my thumb pressure).   The FETs trigger is derived from the 1KHz clock source (my Arb).     

The video was first shot in real time.  It was then stretched to slow it down by 4X.   The last segment was shot at 1000fps.   The camera can only capture a few seconds of data in this mode.   

I used the Gossen the last time I ran this test as well as it's the only other handheld meter I have that will display three places beyond the decimal point.  Obviously we would expect my other lower resolution meters to be much faster.   I'm fine with the settling time of the 121Gw, if the meter would actually settle.

This Gossen meter is not stock.  I had added some magnetic shielding (Netic) to the rear and some copper shielding to the front.  Otherwise  it was a great sensor for detecting all sorts of environmental conditions.   :-DD :-DD    I would actually say the meter could be dangerous to use in CAT III.   Like the 121, there were modes where the meter would show very low voltages in the presence of high voltage levels.  Really bad IMO.   
 
See Part 4 @ 7:40
https://www.youtube.com/watch?v=-eUkSufMK5A (https://www.youtube.com/watch?v=-eUkSufMK5A)
Title: Re: Handheld meter electrical robustness testing.
Post by: bitseeker on November 18, 2019, 01:28:20 am
Yeah, I remember the shielding you added to the Gossen. I quite enjoy all the fixes you come up with.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 18, 2019, 03:28:50 pm
About the 121gw capacitance drifting, my (uneducated) guess is that it might have something to do with the SM6T22CA (D13 on the original 121 schematics), these devices seems to have a lot of nonlinear, voltage and probably temperature dependent capacitance behavior.

Perhaps a reason D13 now seems to been replaced with a traditional transistor clamp circuit in the latest hardware revision.

Yep , appology because I said it's not D13 , but it is .
Today I made some experiments , removed D13 and the drift is gone as far I had time to check .
Definitively the transil diode has capacitance very dependent on temperature and voltage if you check it with a LCR meter . Probably leakage resistance too.
Without it in circuit the reference cap 510pF now measure 200pF but as I said I couldn't see drift .
I didn't checked yet if it's possible to calibrate the meter and how much other functions are affected ...
If it's confirmed on the PCB is the place where the 2 transistors unpopulated in the schematic could be soldered .
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 18, 2019, 07:23:30 pm
Great to have that confirmed, these TVS diodes really does not seem like devices you want in a capacitance measuring circuit. Interesting both the schematics and PCB have allowance for alternative components with Q1-Q2, question is what type transistors to use though. I wonder why UEi opted for the TVS, seems like a bad choice anyway. 

I think you should be able to re-calibrate the caps mode.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 18, 2019, 07:50:17 pm
I can't recalibrate ... for some reason using a 10nF like in instructions result in 0.000nF readings in this range for any cap , so the only option is to reload the saved calibration . Maybe it's a bug , I tried many times even with different values , I don't think I did something wrong  :-//
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 18, 2019, 11:41:16 pm
Come to think of it, when I measured the waveform 121gw puts out in caps mode, its been some time ago but I seem to remember the frequency of that waveform was much lower than it should have been according to the way 121gw setup the hy3131. It was like a 'hidden' capacitor was present slowing the waveform down. But D13 is not directly in parallel with the input jacks, but still its absence could perhaps affect the circuit more than what the calibration routine can handle.

Title: Re: 121GW capacitance mode & specifications
Post by: Dr. Frank on November 19, 2019, 05:56:12 pm
Hey Joe, dear dcac, CDaniel,

Maybe you remember, that I made a strict review on the basic characteristics  of the 121GW: https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1687298/#msg1687298 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1687298/#msg1687298)
where I quantitatively verified the specifications of DC/AC voltage and current and Ohm.
My 121GW is from the 2nd batch from Kickstarter, delivered in July 2018 with FW 1.22, now 2.02, and its hardware is still very similar to Joes latest 121GWs.

Very soon I observed and described several problems with the Ohm mode, especially, that negative Ohm values are clipped to zero, so there is a 'hidden' offset (originating from initial calibration), which affects the accuracy of low Ohm measurements, as this offset can't be zeroed.

That clipping effect of Ohm mode is obviously removed latest with FW 2.02, but still present on the capacitance mode.
That explains the big errors you all see with small pF capacitors. This is evident as a threshold effect in capacitance value, i.e. the calibrated zero value plus the actual offset will always be subtracted from the real value. Capacitors smaller than this threshold will be displayed as 0.000pF, and bigger ones will show too small a value.

If I let my 121GW sit for a while in the 10nF range, it will possibly display some pF offset with open leads, and if I then zero the reading, I always get very precise values, even with pF capacitors (e.g. 39pF).
If that obvious (zero) drift is zeroed repeatedly between subsequent readings, then the measurement of the capacitors value is consistently precise, better than the specified 2.5%.
Long measurements on this zero drift make no real sense, I think.

Btw.: I can really check the accuracy by my DE-5000 LCR meter, which is specified down to 0.3% accuracy, depending on range and test frequency.

Interestingly, the actual manual (9/2019) still specifies this mode as:

(https://www.eevblog.com/forum/index.php?action=dlattach;topic=48998.0;attach=875262;image)


I loaded FW 1.17, and indeed, the resolution then was 3 digits only, i.e. 10pF resolution in the lowest range.

That also means formally, that +5 digits, or 50 pf variation are allowed.
So do not expect too much of accuracy, because of this misleading specification, or because of the additional digit resolution.
The specification might be updated / improved to the 4 digit resolution, which seems to be quite reasonable, if that threshold problem can be solved.

Also pay attention if you try to re-calibrate the capacitance ranges.
There is no entry for zero value calibration in the small table inside the chapter ZERO OFFSET CALIBRATION.
In the big colored table, though, there is a scrambled entry, 'R1 : ', which might indicate that the first calibration point with open leads sets the offset, and the 2nd one with the nominal reference capacitor sets the gain.
That might explain CDaniels problem, that 0.000 is displayed for a 10nF capacitor, after calibration.


Similar aspects hold for the 50.000 Ohm range, as this has even +20 digit or 20 mOhm  specified deviation.
CDaniel criticized in another thread:
'2 - in 50ohm range the last 2 digits are pretty useless . Every time you short the leads you get different reading and fluctuating'

At first, I think that you simply measured the varying contact resistance of your probe or short, whatever you have used.
This has nothing to do with the 121GW itself.

Instead, I would say in a general manner, that it is very difficult to make reasonable Ohm measurements in the 1..50 mOhm range with the 2W method only.
The 4W / Kelvin method is required to safely cancel lead and contact resistances.

Additionally, the 121GW uses about 500µA in this range only, i.e. 1 mOhm equals about 0.5µV, so proper cancellation of thermo voltages is also required, i.e. usually the OFFSET COMPENSATION function does this job.

By using solid cables, and proper zeroing (REL), e.g. by use of an appropriate short, one can cancel both, contact resistances and thermo voltage, even on the 121GW.
By this method, and in contrast to CDaniels tests, I get quite accurate and stable readings at 100 mOhm and upper settings on my decade resistance box, and the deviation or fluctuation from nominal are a few mOhms only. Frequent zeroing is also required here.

You can as well measure/detect the variation of the contact resistance of the switches.
So that low resistance resolution can be quite useful, although I would always prefer an appropriate instrument for such measurements, like my 34465A.

Frank
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 19, 2019, 09:33:58 pm
So basically what you are saying , that drift is acceptable bacause we can zero it and still in specifications ? Sorry but for some people is not good enough  ;D. What meter beside this do you use and is drifting ?

I did the cap calibration both way , zero offset and then full scale gain with 10nF or just full scale gain . Same result , dead range .

We understand that this is not 4 wire resistor mesurement , but the crappy design with low current is making things much worse that could be . Indeed , the voltage across the DUT resistor is so low that is comparable with every solder joint thermo voltage . You can verify this by heating the input jack , or every solder joint in the signal path . The value is drifting very much .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2019, 02:41:59 am
In Part 4, we compare the 121GW's bargraph, 3dB point and freq counter with other DMMs.   We then attempt to align one if the old production meters using the original procedure.   We finish up repeating  one of Dave's recent tests.   There's a few other other bits sprinkled along the way. 

https://www.youtube.com/watch?v=-eUkSufMK5A (https://www.youtube.com/watch?v=-eUkSufMK5A)
Title: Re: Handheld meter electrical robustness testing.
Post by: Dr. Frank on November 20, 2019, 02:38:27 pm
So basically what you are saying , that drift is acceptable bacause we can zero it and still in specifications ? Sorry but for some people is not good enough  ;D. What meter beside this do you use and is drifting ?

Please, do not imply things, which I have never said.

Whenever you make measurements with high resolution and for high precision, it's always good metrological practice to first zero the meter, or to cancel offsets by other methods. That is even mentioned in the manual of the 121GW for the 50 Ohm range, and for 50 mVdc, but also in manuals from more sophisticated instruments.
 
I have provided an explanation and effective methods which will help users to achieve precise measurements with the 121GW, by mitigating its physical or circuit limitations.

I see no use case for making drift measurements, especially if you simply want to determine the value of a capacitor, or of a resistance. I also can not reproduce such an excessive drift, that would prohibit precise measurements.


We understand that this is not 4 wire resistor mesurement , but the crappy design with low current is making things much worse that could be . Indeed , the voltage across the DUT resistor is so low that is comparable with every solder joint thermo voltage . You can verify this by heating the input jack , or every solder joint in the signal path . The value is drifting very much .

Again, I do not share your opinion about the design.
It is like it is, and regardless of its shortcomings, it's anyhow possible to make useful and quite precise low level measurements, especially in relation to the form factor and price area of this DMM.

It's as well a good metrological practice to avoid or cancel thermo voltages in your measurement setup, so I do not understand, what you want to contribute to this aspect.


Maybe you should simply sell your 121GW, if you are personally dissatisfied.
Your permanent complaints, w/o any constructive hints / ideas really do not help anybody here in this forum.

Frank
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2019, 04:08:00 pm
I have included my attempt to reproduce Dave's speed test in Part 4.   Dave does claim the "...I checked, the Keysight "drifts" in a similar way,.... "
https://youtu.be/-eUkSufMK5A?t=460
I overlaid Dave's two meters to better show how the 121 compares with the Keysight meter.    I also included more information about my test.   

I also show the effect of aligning the capacitance function of the old production hardware using the procedure Dave supplied with the prototype.
https://youtu.be/-eUkSufMK5A?t=905 

Looking in the latest manual for the 121GW, page 53, VA connects is not going to yield good results.  I covered it over 2 years ago.  You would think someone would have taken the time to correct it by now. 

The biggest problem I saw so far with the old production hardware, with 1.57 or 2.02 firmware installed was that it failed to give any indication to the user that  high voltages could be present in all conditions.  IMO, this is really bad.    A fellow member had pointed out that I had seen this with the prototype as well.   I guess a few of you remember important things like this.    This should NEVER happen.

The attached is from EN 61010-2-033:2012.   See note b).    Seeing stuff like this and the Gossen with its latching relays getting through chips away at my trust in them. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 20, 2019, 06:38:34 pm
The biggest problem I saw so far with the old production hardware, with 1.57 or 2.02 firmware installed was that it failed to give any indication to the user that  high voltages could be present in all conditions.  IMO, this is really bad.    A fellow member had pointed out that I had seen this with the prototype as well.   I guess a few of you remember important things like this.    This should NEVER happen.

The attached is from EN 61010-2-033:2012.   See note b).    Seeing stuff like this and the Gossen with its latching relays getting through chips away at my trust in them.
(Sorry, I am having trouble to catch up with all things...)
Do you mean that 121GW fails to present a OL on the display? Or only on certain ranges?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2019, 08:28:55 pm
The biggest problem I saw so far with the old production hardware, with 1.57 or 2.02 firmware installed was that it failed to give any indication to the user that  high voltages could be present in all conditions.  IMO, this is really bad.    A fellow member had pointed out that I had seen this with the prototype as well.   I guess a few of you remember important things like this.    This should NEVER happen.

The attached is from EN 61010-2-033:2012.   See note b).    Seeing stuff like this and the Gossen with its latching relays getting through chips away at my trust in them.
(Sorry, I am having trouble to catch up with all things...)
Do you mean that 121GW fails to present a OL on the display? Or only on certain ranges?

https://www.youtube.com/watch?v=gEVwjxPsI6w (https://www.youtube.com/watch?v=gEVwjxPsI6w)
Title: Re: Handheld meter electrical robustness testing.
Post by: Monkeh on November 20, 2019, 08:49:21 pm
Not in any defense of any issues with meters, and this has probably been pointed out before..

These sorts of issues (the Gossen issue being a grand example) are exactly the reason safe isolation procedure involves verifying the meter. Prove meter, test circuit, prove meter, rinse and repeat.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 20, 2019, 08:56:37 pm
So, it is not really a problem with indicating an overvoltage condition but instead a problem in effectively finding the correct range to display. Given the read voltage on production #2 meter is so off, I imagine the circuitry/firmware completely failed to read the inputs. 

Given the cost of every certification run is quite high, I have my doubts if every firmware revision goes through that process...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 20, 2019, 09:18:49 pm
So, it is not really a problem with indicating an overvoltage condition but instead a problem in effectively finding the correct range to display. Given the read voltage on production #2 meter is so off, I imagine the circuitry/firmware completely failed to read the inputs. 

Given the cost of every certification run is quite high, I have my doubts if every firmware revision goes through that process...

Guessing you skipped a bit as I clearly show the problem is there even with 1.0 firmware installed.    This problem dates back before the prototype 121GW I had looked at.   I didn't make a big deal about it back then as it was, after all, a prototype.   I should mention that someone recently wrote who had remembered seeing that early video.   

Showing a low voltage in the presence of hazardous levels is exactly one of the examples used to describe an ambiguous indication.   Again, I am not a safety expert and there may be a reason conditions like these get a pass.  Personally, I think it dilutes the cert.   

I would expect companies that take these safety standards serious re-certify their product as changes made.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Kosmic on November 21, 2019, 02:47:59 am
Apparently the last DMM made by Solartron (SI 7063) had a similar problem. In rare case the decimal point was not placed at on the right spot. So, you could read 10V in presence of 1000V. Since the bug was in the ASIC, they endedup scrapping the whole product and destroying all produced SI 7063.

https://www.eevblog.com/forum/testgear/my-_new_-old-schlumberger-si-7063-dmm/msg2591991/#msg2591991 (https://www.eevblog.com/forum/testgear/my-_new_-old-schlumberger-si-7063-dmm/msg2591991/#msg2591991)
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on November 21, 2019, 03:56:17 am
So, it is not really a problem with indicating an overvoltage condition but instead a problem in effectively finding the correct range to display. Given the read voltage on production #2 meter is so off, I imagine the circuitry/firmware completely failed to read the inputs. 

Given the cost of every certification run is quite high, I have my doubts if every firmware revision goes through that process...

Guessing you skipped a bit as I clearly show the problem is there even with 1.0 firmware installed.    This problem dates back before the prototype 121GW I had looked at.   I didn't make a big deal about it back then as it was, after all, a prototype.   I should mention that someone recently wrote who had remembered seeing that early video.   
I watched the entire video, but I just mentioned #2 as it was the first that showed teh issue.

Showing a low voltage in the presence of hazardous levels is exactly one of the examples used to describe an ambiguous indication.   Again, I am not a safety expert and there may be a reason conditions like these get a pass.  Personally, I think it dilutes the cert.   
My observation is simply my guess as to why there is no OL/hazardous indication: not a deliberate omission but I believe the meter is simply unaware of a high voltage on its inputs due to the autorange bug. In the end, the effect is the same regardless of the goof up.

I would expect companies that take these safety standards serious re-certify their product as changes made.   
Completely agree, although I suspect the rate of firmware releases does not allow for such intense testing - it costs real $$$ real fast. (although I didn't follow the FW evolution that close)
Title: Re: 121GW capacitance mode & specifications
Post by: dcac on November 21, 2019, 02:23:14 pm
Hey Joe, dear dcac, CDaniel,

That clipping effect of Ohm mode is obviously removed latest with FW 2.02, but still present on the capacitance mode.
That explains the big errors you all see with small pF capacitors. This is evident as a threshold effect in capacitance value, i.e. the calibrated zero value plus the actual offset will always be subtracted from the real value. Capacitors smaller than this threshold will be displayed as 0.000pF, and bigger ones will show too small a value.

If I let my 121GW sit for a while in the 10nF range, it will possibly display some pF offset with open leads, and if I then zero the reading, I always get very precise values, even with pF capacitors (e.g. 39pF).
If that obvious (zero) drift is zeroed repeatedly between subsequent readings, then the measurement of the capacitors value is consistently precise, better than the specified 2.5%.
Long measurements on this zero drift make no real sense, I think.

Btw.: I can really check the accuracy by my DE-5000 LCR meter, which is specified down to 0.3% accuracy, depending on range and test frequency.

Interestingly, the actual manual (9/2019) still specifies this mode as:

(https://www.eevblog.com/forum/index.php?action=dlattach;topic=48998.0;attach=875262;image)


I loaded FW 1.17, and indeed, the resolution then was 3 digits only, i.e. 10pF resolution in the lowest range.

That also means formally, that +5 digits, or 50 pf variation are allowed.
So do not expect too much of accuracy, because of this misleading specification, or because of the additional digit resolution.
The specification might be updated / improved to the 4 digit resolution, which seems to be quite reasonable, if that threshold problem can be solved.

Frank

Hi Dr. Frank

If I connect a 330pF mica capacitor to my 121gw to lift offset above the zero clipping, it will initially read 178pF and within minutes increase to about 195pF. This is without touching or holding the meter so the increase is solely from internal temperature rise in the 121gw. If I let the meter sit for more than 20 minutes or so it will very slowly start to approach to correct value of 330pF. I’m fairly confident I can contribute this behavior to capacitance drift in the D13 TVS diode, but wouldn’t be surprised if there are 121gw’s were D13 is not at all as bad as this, I got an unlucky D13 I guess.

The 121gw user manual doesn't seem to mention any warmup period, not even for the calibration procedure, from when to expect the meter to be accurate/stable. But from using many different handhold DMM’s I’ve come to expect them to be fairly accurate after 3-5 minutes, usually they are accurate much earlier than this.

Edit: Not so sure it's D13 after all, see post below.
Title: Re: Handheld meter electrical robustness testing.
Post by: Dr. Frank on November 21, 2019, 03:21:10 pm
Hi dcac,
Thank you for your observations.

On my 121GW, I see a similar behavior (as briefly indicated), but not that extreme.
Initially, it also reads exactly 0.000 nF, and either after a while, or after using other modes, it will come up with some non zero reading of several 10pF.

Only then, it's possible to use REL, and get quite precise measurements.
Mine does not drift that much and not so long.

Probably it's not the leakage of the TVS, but its capacitance.
If I interpret it correctly, the SM6T22CA has around 1nF itself @ 1V, (see diagram), which will be in parallel to the DUT, and this high capacity offset will probably be calibrated into the initial zero cal point.
That 1nF capacitance will slightly vary over temperature and voltage, but that transforms into a big variance on pF scale, which explains the observed effects.

If you replace that TVS by something else, a new zero calibration is required.

Therefore I would greatly appreciate, if Joe could publish the correct calibration procedure for zero, which would reset the threshold.

Frank
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 21, 2019, 06:23:25 pm
I wrote how much the reading is changing , from 510pF to 200pF , but the transil diode has only 50pF measured with a LCR bridge at 100Hz , 0V bias . It's not straightforward , probably has some leakeage resistance and the capacitance and leakage resistance is dependent on the voltage , frequency applied and of course temperature .
The maximum drift i saw in my meter was about 80pF , typically is lower , but extremely annoying to know that you have a meter that drifts . This a matter of principle , not that I don't have the means to measure caps .
When the calibration procedure for caps will become available I will investigate more .
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 21, 2019, 08:31:48 pm
Well I took the back cover of my 121gw and repeated the test with the 330pF mica and the behavior started out just as before. Then I put my finger directly on D13 probably elevating its temperature several degrees expecting the reading to quickly increase, but no change at all was really noticeable, all that happened was the reading jumping around from interference of my finger touching the circuit, but as soon as I removed it the value stabilized again. But still slowly increasing just like before. I had already checked the mica cap with another meter and it was perfectly stable. Now I really don’t know. I tried breathing some hot air over the PCB and that did seem to have an effect but from what component I could not tell.

Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 21, 2019, 09:50:10 pm
Remove it and confirm or not that the drift is gone .
I didn't said temperature is the main cause for the drift , the capacitance is changing with temperature but I touch it with the soldering iron .
The capacitance is changing with the voltage too , could be a small DC voltage across it slowly creeping up or down and when you cycle trough functions is reseting to the initial value ...
Just don't try to recalibrate wiithout saving first the calibration data  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2019, 04:25:06 pm
Have those of you wanting the old procedure requested it from Dave?    I haven't seen anything from him after I brought it up.   

I have started to work on part 5 (firmware).    My plan is repeat the same tests I did with the prototype with a few changes.

1.9Mohm resistor stability/noise for various versions of firmware.    This 1.9M was something I had setup to repeat one of Frank's tests.   After seeing Dave's mechanical switch test,  I also plan to use the 40 ohm.  I doubt I will check both meters as the hardware appears to be the same between them.    Depending how things go, if it looks like the old production hardware behaves the same as the prototype, I may not run all the versions of firmware.   

If there is anything else you would like to see, feel free to ask.   

******
It appears 1.05 is when they introduced the extra digit for the 50 ohm range. 
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on November 23, 2019, 08:04:34 pm

******
It appears 1.05 is when they introduced the extra digit for the 50 ohm range.

Not exactly sure what you mean but it's been my understanding all FW released to the public, or since 1.02 anyway, have had the same resolution in all ohms ranges and 50 ohms range reading 50.000 ohms.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 23, 2019, 08:11:50 pm
If there is anything else you would like to see, feel free to ask.   

At the start of your last video where you had all the meters lined up for comparison I thought perhaps you may have been able conduct a similar test but set all the meters for Min/Max so as to gauge which meters can not only display a reading but capture it as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2019, 08:47:21 pm

******
It appears 1.05 is when they introduced the extra digit for the 50 ohm range.

Not exactly sure what you mean but it's been my understanding all FW released to the public, or since 1.02 anyway, have had the same resolution in all ohms ranges and 50 ohms range reading 50.000 ohms.

I went from 1.00 to 1.05.   I will add 1.02 to the mix and see if it also has the higher res.
***
Yes, 1.02 does indeed support the higher resolution as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2019, 08:52:27 pm
If there is anything else you would like to see, feel free to ask.   

At the start of your last video where you had all the meters lined up for comparison I thought perhaps you may have been able conduct a similar test but set all the meters for Min/Max so as to gauge which meters can not only display a reading but capture it as well.

The one where I talked about the 61010 standard and applied the DC biased 60Hz AC waveform?  If so, I am not sure that the meters can all capture the min/max in the modes I was using.   Let me know and I will check. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 23, 2019, 09:05:28 pm
Yes that was the test, I frequently use this function and wondered what the result would be from a meter which was unable to settle or stabilise for the capture to occur. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 23, 2019, 10:03:53 pm
Yes that was the test, I frequently use this function and wondered what the result would be from a meter which was unable to settle or stabilise for the capture to occur. 

I am not sure we are still talking about the same video as the problem I am showing in that last video appears not to be related to settling time but rather some problem with the autorange. 

If this is really what you are asking about,  for example, you would like to see the 121GW old hardware placed into its DC function with the Max selected.  Apply the DC biased 60Hz AC waveform and see if the 121GW can detect the DC value?   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 24, 2019, 02:23:55 pm
I've started looking at the 121's filter response for a few different modes.   As before, I'm doing a sweep from 0.1Hz to 10Hz.    Looking at the older firmware and comparing that with data I collected from the prototype, there appears to be no difference.  I wasn't expecting there to be but its good see reproducible results.  I've also looked that the noise levels of the two meters and nothing odd shows up.    Time to have a look at the newer versions of firmware.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 24, 2019, 03:45:48 pm
The filter was changed in successive firmware updates for resistance just because we complained that is very sensitive to mains noise ( and still is ) , maybe you should test this , injecting some AC 50/60Hz and compare with other meters .
From my tests is at least 10 times more sensitive than a Fluke ...
The main entry point for noise are the long leads , so a bad designed meter appears to be good when tested with a short testing jig ... that's why some "engineers" hate that people have hands and use them when measuring  ;D


 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 24, 2019, 04:25:26 pm
The filter was changed in successive firmware updates for resistance just because we complained that is very sensitive to mains noise ( and still is ) , maybe you should test this , injecting some AC 50/60Hz and compare with other meters .
From my tests is at least 10 times more sensitive than a Fluke ...
The main entry point for noise are the long leads , so a bad designed meter appears to be good when tested with a short testing jig ...

It's interesting to see how the filters for the various modes, not just the resistance, have evolved.  This is basically going to be the focus of the next video.   I like your idea of testing the 50/60Hz notch with a direct injection.   I've haven't done much outside of showing the effects of the 60Hz tape eraser. 

Are you proposing mixing a 50/60Hz test signal with another signal (for example, measure 1VDC modulated with a 100mV AC signal), or just injecting the AC?    Did you post any data from your tests?  If so, please provide a link.  I would like to go over it.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 24, 2019, 04:59:32 pm
Nothing complicated , for resistance inject AC across the test resistor , for every range .
For voltage maybe is enough just to inject an AC voltage and see if the 0 V DC fluctuates .

That tape eraser is a good indication that a meter is sensitive to noise , but you don't know for sure if the noise is entering through inputs or has a problem with the shielding inside , or other issue .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 24, 2019, 05:12:33 pm
Nothing complicated , for resistance inject AC across the test resistor , for every range .
For voltage maybe is enough just to inject an AC voltage and see if the 0 V DC fluctuates .

That tape eraser is a good indication that a meter is sensitive to noise , but you don't know for sure if the noise is entering through inputs or has a problem with the shielding inside , or other issue .

When you ran this test, did you use a constant voltage for all resistance ranges?   What level?  Both 50 and 60Hz?  Did you center the resistance on each range?   Did you test all the various versions of firmware?   Which Fluke meters did you use as a comparison? 

I am interested in seeing your data if you don't mind along with as much details as you can provide about your setup.   I may attempt to just replicate your testing to see how our results compare.

*****
Also, I am interested in knowing more about your coupling network.   Please fill in some blanks and we can discuss. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 24, 2019, 09:03:22 pm
Yes that was the test, I frequently use this function and wondered what the result would be from a meter which was unable to settle or stabilise for the capture to occur. 

I am not sure we are still talking about the same video as the problem I am showing in that last video appears not to be related to settling time but rather some problem with the autorange. 

If this is really what you are asking about,  for example, you would like to see the 121GW old hardware placed into its DC function with the Max selected.  Apply the DC biased 60Hz AC waveform and see if the 121GW can detect the DC value?

Finished looking at the filters.   Attempted using the Max as I described above.   Shown with all 4 meters in parallel.  121 is attached to the Fluke 187.   189 and 187 are connected to the supply.  Note that that DC value for the Fluke 189 matches with the Fluke 187 as it should.   121GW with Max selected showing 5VDC.  The autorange for  AC and AC+DC both appear fine.    Hope this answers your question. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 24, 2019, 11:03:15 pm
Thanks Joe for your efforts. I could not find any mention of this meters min/max operation anywhere else and as you already had it alongside some other trusted meters I figured it was a good opportunity to ask if this feature was in agreement with the others.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 24, 2019, 11:14:13 pm
Oh, you just wanted to see how the min/max compared with others, not if it was able pick up the high voltage in this particular test case.   It was your mentioning that last video that threw me off. 

The 121GW has that 1ms peak detect as well as the auto and manual hold.    These are all covered in the manual. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on November 24, 2019, 11:27:14 pm
Sorry, I probably could have worded that request a bit better, it was more the meters ability to capture rapidly changing readings and how it compared against the others in that particular mode.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 25, 2019, 01:21:24 am
Now that I believe I understand what you are looking for, I've shown similar tests in the past.   I'll just follow that same sort of format.   I suspect the software video will be a little short so maybe I can include it with part 5.   

******
For those of you that joined my poll, you voted to see this meter ran by a large margin over the Gossen and Hitachi.    If you feel something is missing, now is the time to speak up.   This following is the order that I plan to run these tests.   

Part 6 will include the drop test, chemical  exposure, temperature things of that nature where I am not expecting to see any problems. 

Part 7 will be the transient tests.   Per Franks posts, the first thing I plan to do is have a look at the front end and see what they have done.  Then we can do some DC checks to try and get a feel for what to expect.   This test will include the typical AC line tests,  my grill starter, the large ESD gun and then the higher energy transients.   The prototype had not problems surviving the gas grill starter test but with the new improved front end, it may be worth having another look.  I didn't have the gun built back then, so that will be a new test.  The latest manual states "Transient Protection6 kV 2 Ω, Pulsed Source".   If the meter is still alive at the 5.8KV, I think we need to celebrate.       

Part 8 life cycle the switch.  No spit shine, no cleanups, no yellow post it notes,   just 50,000 full cycles.   I'll compare the contact resistance with other meters and we can have a look with my new used microscope head.   

After this, I would say anything goes. 
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 25, 2019, 06:17:43 am
We all wait that switch test  :popcorn:

Meantime , my setup was simple , signal generator , constant voltage in parallel with the DUT resistor , I cranked up the voltage untill the value displayed fluctuates . I didn't choose the resistor to be in mid range or something ... of course you can standardise the setup as you wish .
The Fluke used were an 187 and an 867B graphical multimeter . So at 1Vpp 50Hz/60Hz 121GW fluctuates like mad but in a Fluke I could inject up to 10Vpp with minimal fluctuations , maybe 2-3 counts .
For Volts DC I didn't found to be a lack of filtering , the results were similar , of course I my test was mainly qualitative , not to measure exactly . You can go as deep as you like  :D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 25, 2019, 01:30:31 pm
I hope to get a part done each week, so in about 4 weeks I hope to show the results of the switch test.   

We all wait that switch test  :popcorn:

Meantime , my setup was simple , signal generator , constant voltage in parallel with the DUT resistor , I cranked up the voltage untill the value displayed fluctuates . I didn't choose the resistor to be in mid range or something ... of course you can standardise the setup as you wish .
The Fluke used were an 187 and an 867B graphical multimeter . So at 1Vpp 50Hz/60Hz 121GW fluctuates like mad but in a Fluke I could inject up to 10Vpp with minimal fluctuations , maybe 2-3 counts .
For Volts DC I didn't found to be a lack of filtering , the results were similar , of course I my test was mainly qualitative , not to measure exactly . You can go as deep as you like  :D

Very odd.   This is pretty basic stuff,  so lets try and clear up what you are asking.   Anything I have that works down to 50Hz is DC coupled and will have a 50ohm source. These are meant to drive a 50ohm load.  Let's ignore that and say you plan to go directly across the test resistor.    I would expect placing that 50ohm source in parallel with a 50ohm test resistor for example will yield somewhere around 25ohms.     Placing it in parallel with a 20Meg will yield something around 50ohms.  You could add a large blocking cap (reason I asked about the coupling network) to strip the DC but you never mention it.   

Let's just ignore all of that basic detail and assume your generator is DC coupled and is capable of driving 20Vp-p, with a 50ohm source.    Now run that to a 50ohm thru terminator.  Again, I would expect 25 ohms with the generator output set to 0V.   At least we are in the center of the 50 ohm range.   Assuming this setup is what you are doing, I would fully expect both meters to be effected as you turn up your generator to 20Vp-p.   Maybe an offset.   

With the 121GW, I suspect it will depend on the firmware that is installed.   If you installed 2.02 for example, with your generator set to 2 volts (for your 1V test case), I wouldn't be surprise to see that meter still be all over the place.   As Dave's speed test video shows, in that 50ohm range we can guess that they have continued to move the cutoff higher.  From the tests I show, we could see the 1.00 firmware provided a much more stable display than 2.02 which also backs up what I am suggesting.

We know the meter is sensitive to the 60Hz from the tape eraser.  I can only imagine what directly injecting a 1Vp-p signal will do to it.  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: barjammar on November 25, 2019, 01:57:14 pm
I can’t find suggestions for improvements for the 121GW but Dave should certainly adjust the bottle opener. (See Video).
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 25, 2019, 03:11:49 pm
I hope to get a part done each week, so in about 4 weeks I hope to show the results of the switch test.   

We all wait that switch test  :popcorn:

Meantime , my setup was simple , signal generator , constant voltage in parallel with the DUT resistor , I cranked up the voltage untill the value displayed fluctuates . I didn't choose the resistor to be in mid range or something ... of course you can standardise the setup as you wish .
The Fluke used were an 187 and an 867B graphical multimeter . So at 1Vpp 50Hz/60Hz 121GW fluctuates like mad but in a Fluke I could inject up to 10Vpp with minimal fluctuations , maybe 2-3 counts .
For Volts DC I didn't found to be a lack of filtering , the results were similar , of course I my test was mainly qualitative , not to measure exactly . You can go as deep as you like  :D

Very odd.   This is pretty basic stuff,  so lets try and clear up what you are asking.   Anything I have that works down to 50Hz is DC coupled and will have a 50ohm source. These are meant to drive a 50ohm load.  Let's ignore that and say you plan to go directly across the test resistor.    I would expect placing that 50ohm source in parallel with a 50ohm test resistor for example will yield somewhere around 25ohms.     Placing it in parallel with a 20Meg will yield something around 50ohms.  You could add a large blocking cap (reason I asked about the coupling network) to strip the DC but you never mention it.   

Let's just ignore all of that basic detail and assume your generator is DC coupled and is capable of driving 20Vp-p, with a 50ohm source.    Now run that to a 50ohm thru terminator.  Again, I would expect 25 ohms with the generator output set to 0V.   At least we are in the center of the 50 ohm range.   Assuming this setup is what you are doing, I would fully expect both meters to be effected as you turn up your generator to 20Vp-p.   Maybe an offset.   

With the 121GW, I suspect it will depend on the firmware that is installed.   If you installed 2.02 for example, with your generator set to 2 volts (for your 1V test case), I wouldn't be surprise to see that meter still be all over the place.   As Dave's speed test video shows, in that 50ohm range we can guess that they have continued to move the cutoff higher.  From the tests I show, we could see the 1.00 firmware provided a much more stable display than 2.02 which also backs up what I am suggesting.

We know the meter is sensitive to the 60Hz from the tape eraser.  I can only imagine what directly injecting a 1Vp-p signal will do to it.  :-DD

This was not meant for the 50ohm range , low resistors , so you kill the generator , that's other story . Use 1K , 10K , 100K , 1M or any values you wish .
Some generators have internal output caps , you can add one , and a voltmeter to measure the actual AC voltage  :D. Anyway this was not suposed to be an exact voltage test , just to find the root couse why is more sensitive to noise than other meters and ...   the fluctuating reading is what you  see and not something precise to corelate with the input voltage in milivolts  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 25, 2019, 03:42:08 pm
Normally, I wouldn't use a bottle cap opener on a twist off.   :-DD


I hope to get a part done each week, so in about 4 weeks I hope to show the results of the switch test.   

We all wait that switch test  :popcorn:

Meantime , my setup was simple , signal generator , constant voltage in parallel with the DUT resistor , I cranked up the voltage untill the value displayed fluctuates . I didn't choose the resistor to be in mid range or something ... of course you can standardise the setup as you wish .
The Fluke used were an 187 and an 867B graphical multimeter . So at 1Vpp 50Hz/60Hz 121GW fluctuates like mad but in a Fluke I could inject up to 10Vpp with minimal fluctuations , maybe 2-3 counts .
For Volts DC I didn't found to be a lack of filtering , the results were similar , of course I my test was mainly qualitative , not to measure exactly . You can go as deep as you like  :D

Very odd.   This is pretty basic stuff,  so lets try and clear up what you are asking.   Anything I have that works down to 50Hz is DC coupled and will have a 50ohm source. These are meant to drive a 50ohm load.  Let's ignore that and say you plan to go directly across the test resistor.    I would expect placing that 50ohm source in parallel with a 50ohm test resistor for example will yield somewhere around 25ohms.     Placing it in parallel with a 20Meg will yield something around 50ohms.  You could add a large blocking cap (reason I asked about the coupling network) to strip the DC but you never mention it.   

Let's just ignore all of that basic detail and assume your generator is DC coupled and is capable of driving 20Vp-p, with a 50ohm source.    Now run that to a 50ohm thru terminator.  Again, I would expect 25 ohms with the generator output set to 0V.   At least we are in the center of the 50 ohm range.   Assuming this setup is what you are doing, I would fully expect both meters to be effected as you turn up your generator to 20Vp-p.   Maybe an offset.   

With the 121GW, I suspect it will depend on the firmware that is installed.   If you installed 2.02 for example, with your generator set to 2 volts (for your 1V test case), I wouldn't be surprise to see that meter still be all over the place.   As Dave's speed test video shows, in that 50ohm range we can guess that they have continued to move the cutoff higher.  From the tests I show, we could see the 1.00 firmware provided a much more stable display than 2.02 which also backs up what I am suggesting.

We know the meter is sensitive to the 60Hz from the tape eraser.  I can only imagine what directly injecting a 1Vp-p signal will do to it.  :-DD

This was not meant for the 50ohm range , low resistors , so you kill the generator , that's other story . Use 1K , 10K , 100K , 1M or any values you wish .
Some generators have internal output caps , you can add one , and a voltmeter to measure the actual AC voltage  :D. Anyway this was not suposed to be an exact voltage test , just to find the root couse why is more sensitive to noise than other meters and ...   the fluctuating reading is what you  see and not something precise to corelate with the input voltage in milivolts  ;D

Even with a shorted output, I wouldn't expect it to kill a generator.   That would be a pretty poor design.    I would expect 1K to read around 47.6 ohms.   As you go higher in values, you will be closer to 50 ohms.  Again, just the basics.    So, no I wouldn't expect a change using the values you mention but it would allow you to get your 20Vp-p with a 10Vp-p generator. 

If your generator is AC coupled, provide the value that it uses, or a brand and model number for yours and maybe I can sort it out.   Again, I am interested in knowing exactly what test you ran and their results.  The more details you supply, the better. 

For testing the filters, as I mentioned, I just expanded on the tests I ran on the prototype over a year ago.  It paints a very clear picture of how the firmware has evolved over the last few years.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on November 25, 2019, 04:38:08 pm
Just test it if you want , it takes 2 min ... I doubt you will see different results because of the generator brand and output cap . Even if you apply an offset it is not important for lack of filtering . This is a comparative test after all , if you test all meters with the same generator and the same conditions should be fair enough .
Title: Re: Handheld meter electrical robustness testing.
Post by: 3db on November 26, 2019, 02:25:55 pm
Hi Joe
Just a wee note to thank you once again for the time,effort,expertise and MONEY you put into testing these meters.
Best regards
3db
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 26, 2019, 06:11:38 pm
Hi Joe
Just a wee note to thank you once again for the time,effort,expertise and MONEY you put into testing these meters.
Best regards
3db

Thanks.   Good to hear you are still enjoying them after all these years.   

Next segment may be a little late as I am hoping to add more to the mix for Muttley.   
Title: Re: Handheld meter electrical robustness testing.
Post by: bc888 on November 27, 2019, 02:51:43 am
Ditto what he said. Just so you know joe, I've read every post at least once, learned a LOT. Thank you for that too.
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on November 27, 2019, 03:01:13 am
Ditto what he said. Just so you know joe, I've read every post at least once, learned a LOT. Thank you for that too.
Ditto here too. I'm too old to read every post but dang it, the testing's great! (I still miss the earlier fireworks fun)  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 28, 2019, 06:28:04 pm
Ditto what he said. Just so you know joe, I've read every post at least once, learned a LOT. Thank you for that too.
Ditto here too. I'm too old to read every post but dang it, the testing's great! (I still miss the earlier fireworks fun)  :-DD

Thanks again for all the comments. 

One downside to looking at higher end products is we don't see a lot of fireworks.   Maybe the 121GW will put on a show. 

Still waiting on parts... 
Title: Re: Handheld meter electrical robustness testing.
Post by: Kosmic on November 29, 2019, 05:04:38 pm
Ditto what he said. Just so you know joe, I've read every post at least once, learned a LOT. Thank you for that too.
Ditto here too. I'm too old to read every post but dang it, the testing's great! (I still miss the earlier fireworks fun)  :-DD

I also echo those comments. Watched most of your videos, good stuff  :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on November 29, 2019, 05:35:55 pm
Thanks.

It's looking like the part I am waiting for to run the test for Muttley is due this coming Monday.  Hopefully I can get things rolling again soon.   The 121GWs are starting to look a little too comfortable.    Rest while you can boys...
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 02, 2019, 03:58:53 am
My parts made it in early, so I ran some tests for Muttley Snickers and finished things up.   

https://www.youtube.com/watch?v=mzBDgxkO3HE (https://www.youtube.com/watch?v=mzBDgxkO3HE)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 03, 2019, 12:56:20 am
I had written TPI requesting the alignment procedure for the 194II, explaining what had happened to the meter.   They were able to supply me with everything I need.   

Points to TPI for customer service!!!!   
Title: Re: Handheld meter electrical robustness testing.
Post by: Scottjd on December 03, 2019, 02:21:56 am
I had written TPI requesting the alignment procedure for the 194II, explaining what had happened to the meter.   They were able to supply me with everything I need.   
Points to TPI for customer service!!!!   
Nice!  :clap: :-+
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 03, 2019, 02:38:48 am
Waiting to see how your long term test results turn out Scott.   If you're able to replicate this problem, shoot me as much detail as you can and I will attempt to replicate it. 

From what I remember with that really old firmware, the meter would stop recording.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on December 03, 2019, 02:51:01 am
My parts made it in early, so I ran some tests for Muttley Snickers and finished things up.   

Many thanks Joe for your fine efforts.   :-+

In case people were wondering why I asked Joe to compare and show the auto hold feature it was because the only guide I had in regards to this meters ability was Scott's video where it failed miserably compared to other meters which incorporate auto hold.

In the comments section of the video linked below Scott declared that this problem has been addressed and resolved with later firmware and Joe's tests indicate that it is now working as expected and comparable with other similar meters with this feature.   


https://youtu.be/l7hBJh_NMOo (https://youtu.be/l7hBJh_NMOo)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 03, 2019, 03:25:31 am
Glad to help.   Hope it covered what you wanted to see with the peak hold and min/max as well.    If not, I could try to add something to the next segment.
Title: Re: Handheld meter electrical robustness testing.
Post by: Muttley Snickers on December 03, 2019, 03:35:35 am
Other than a current craving for triple display meters all is good.   :-DMM :-DMM :-DMM
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 03, 2019, 05:14:54 am
 :-DD   They are nice.   That $120 CEM meter was a deal.   Everytime I play with that UNI-T, I think where is the B model... If Brymen had made that meter to same level I have seen with their other products,  I think I would have a new all time favorite meter.     

After a third cleaning,  I aligned the DCV using my bench meter as a reference.  Shown looking at the output of my old Fluke standard.   The capacitance and ACV  ranges seem good.   The resistance could be improved but it's not horrible.   It's good to see it working again after 3 years.    If it wasn't such a odd ball design, I would attempt to harden the front end.  But it's similar to those cheap ANENG meters and would require a major effort to sort it out. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2019, 02:55:36 am
I have started to work on part 6 and am now thinking that I may try and wrap it up with this video.  There is a fair amount of testing left to do, but most of these take longer to run than showing the results.  I'm sure very few want to see the meter switch cycling for days on end. 

It's going to require another week and the video will more than likely go long.   A couple of spoilers should tie you over.  I ran into a problem with the 121 that I have never seen before, even with the cheap ANENG meters!!    While running the temperature test today, I had the meter down at -10C and noticed that the internal temperature it was reporting was -17.2C.   I have a couple of cheap thermocouples in the box besides the platinum RTD to monitor other areas.  So I connected the Brymen to one.   Looking in the manual, they don't spec the accuracy of this ambient sensor but wow, that's a long way off.   

Stay tuned while I put Production2 to the test. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2019, 09:26:46 pm
Sorry, no post post it notes to try and decode.  Just an HP bench meter reading good old resistance. 
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 08, 2019, 10:33:01 pm
Most thermocouples output a negative voltage at temperatures below freezing. The sign-change can flush out issues with firmware or the CJC. ANENG just uses a fixed room temp value for CJC, in EEPROM.

I made a battery powered reference+Wheatstone bridge, to generate stable (thermocouple) mV signals of either polarity and use that to test hardware.

edit: added schematic of the thermocouple simulator I made with junkbox parts, so it's not perfect. +/-100mV output.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 08, 2019, 10:49:14 pm
Most thermocouples output a negative voltage at temperatures below freezing. The sign-change can flush out issues with firmware or the CJC. ANENG just uses a fixed room temp value for CJC, in EEPROM.

I made a battery powered reference+Wheatstone bridge, to generate stable (thermocouple) mV signals of either polarity and use that to test hardware.

In case the lack of the sign for the Celsius display causes confusion,   13.9F is -10C.  The Brymen also reads -10C.  The 121 is displaying -17.2C.   

I wonder if the 121 is using this reading as their cold junction compensation.  If so it's off by a mile. 
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 09, 2019, 05:47:22 pm
As far as I can tell 121gw only has two temp sensors, one inside the hy3131 chipset and this one doesn't seem to be used at all, and then the smd NTC placed in the upper right corner looking from the PCB side. And this one is read by a rather crude low resolution routine and is used for showing the internal temperature of the meter.

So could they really be doing no cold junction compensation at all? The Temp mode really appears to just read the DCmV and translate this to temperature using a LUT, though a LUT that gives much more resolution than the one for the NTC sensor.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 10, 2019, 12:55:05 am
It would be easy enough to find out by testing it but Dave may be able to find out and add it to the manual.   

That switch has been cycling over 24 hours now.  I'm really curious to know what it looks like.

*****

I went back and watched the two shorter videos Dave made where he cycles the switch on the 121.   It's interesting that the switch that he tests has a different contact design than what was supplied in Production1.   I have yet to take Production2 apart but would assume these two are the same.    He had posted some graphs showing the contact resistance.  It appears they saw up to 2.5ohms once the shim had been installed.    The double dimple design Dave' shows are on the outside,  where mine are all single.   I wonder with the smaller surface area and higher travel speeds being on the outside, if it will wear the same.   

Where Dave had his apart at 1000, 11K, 25K and 51K half cycles,  I plan to leave this one together for all 100K half cycles and this is how I tested the other meters I have looked at.    It still has a good day to go but it's looking good for a weekend upload for Part 6.
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on December 10, 2019, 05:23:23 am
So could they really be doing no cold junction compensation at all? The Temp mode really appears to just read the DCmV and translate this to temperature using a LUT, though a LUT that gives much more resolution than the one for the NTC sensor.

The cold junction compensation done on multimeters is to add the ambient temperature to the thermocoupler temperature and the ambient is often measured inside the multimeter chip, i.e. a long way from the correct location. This also means a multimeter may need one to two hours at a specific temperature before the internal sensor matches the actual cold junction.
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 10, 2019, 09:41:39 pm
I looked again at the code (the disassembled 1.02 FW) and found it this time, and yes they are loading a “cold junction” offset value based on the internal temperature taken from the NTC sensor. Ironically this sensor happens to be placed farthest away possible from the input jacks, but it would probably still be sufficient as long as the meter not recently been subjected to temperature changes, as HKJ suggested.
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 10, 2019, 09:50:59 pm
The Brymen also reads -10C.  The 121 is displaying -17.2C.

I wonder if the 121 is using this reading as their cold junction compensation.  If so it's off by a mile.

The 121 manual specifies operation temperature 0 - 50C, so -10C is outside this range. But the NTC sensor conversion routine seems to be limited to -25C to 85C so at least I hope it is reasonable accurate between 0 - 50C.
Title: Re: Handheld meter electrical robustness testing.
Post by: darik on December 11, 2019, 12:21:37 am
The 121 manual specifies operation temperature 0 - 50C, so -10C is outside this range. But the NTC sensor conversion routine seems to be limited to -25C to 85C so at least I hope it is reasonable accurate between 0 - 50C.

Wow, 0 C as a minimum operating temperature? That is extremely poor. I used to live in Canada, a meter that doesn't work below 0 C is garbage there, useless for anything but exclusively indoor work.

I looked up a Fluke 87 and they claim -20C as their minimum. That is reasonable, a lot of things start acting up at -20. But 0?????

I would imagine that most functions on the 121 work fine well below 0C, perhaps that figure is primarily because of this specific thing. But still, wow, that is a very limiting specification.

Now I'm interested in seeing what functions of the meter don't work at -20.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 11, 2019, 01:45:24 pm
Spoiler for the 121GW fanboys.   I just removed the meter from the jig and installed the batteries.  Both meters in parallel and attached to my 6.750VDC precision reference standard.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 12, 2019, 02:31:41 pm
I have upgraded my 1950's Olympus since looking at the last DMM.   Button on my HP calculator.   We should get a decent view of the 121GW's internals. 
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 12, 2019, 04:47:20 pm
Let's hope will remain unused and that the switch will be like brand new  >:D
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 12, 2019, 07:25:01 pm
I have upgraded my 1950's Olympus since looking at the last DMM.   Button on my HP calculator.

That's an easy one, it's an HP 20S.  :popcorn:
[attachimg=1]

nb.: Image resized for joe's sensibilities (it's his thread!)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2019, 05:52:02 pm
Let's hope will remain unused and that the switch will be like brand new  >:D

It won't be much longer now.  I finished up recording the final video.  Now I just have to edit 2 weeks of testing into an hour or so long video.    I had hoped UEi would release the new firmware before I finished.  I was wanted to look at the 1Meg range Dave mentioned and repeat the AC/DC waveform testing.   Oh well.  This video is going to be packed..

I have upgraded my 1950's Olympus since looking at the last DMM.   Button on my HP calculator.

That's an easy one, it's an HP 20S.  :popcorn:

Not only were you able to ID my calculator, you figured out how to make a picture take up a full page.  Nice job!

Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 13, 2019, 06:14:30 pm
you figured out how to make a picture take up a full page.  Nice job!

You don't get many options with "copy URL", "paste URL". You can only make them expandable if it's one of your own attachments.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 13, 2019, 07:40:07 pm
you figured out how to make a picture take up a full page.  Nice job!

You don't get many options with "copy URL", "paste URL". You can only make them expandable if it's one of your own attachments.

One option would be to DL the picture, then reupload under your account.  Or the simple option, don't link it at all.  After all it was only one previous post. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 14, 2019, 02:35:31 am
One option would be to DL the picture, then reupload under your account.  Or the simple option, don't link it at all.  After all it was only one previous post. 

I fixed it.

PS: The joke was that I know perfectly well what calculator you use, I've seen it in your videos. It's easy to remember because it's the same one I use. Thanks for derailing that.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 03:37:01 am
One option would be to DL the picture, then reupload under your account.  Or the simple option, don't link it at all.  After all it was only one previous post. 

I fixed it.

PS: The joke was that I know perfectly well what calculator you use, I've seen it in your videos. It's easy to remember because it's the same one I use. Thanks for derailing that.
Thanks.  Want to tell a joke, finish this one:

Two 121GWs walked into a bar and sat next to a Brymen and a Fluke. 
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 14, 2019, 04:19:21 am
Two 121GWs walked into a bar and sat next to a Brymen and a Fluke.
...one of them says: can you believe that Keysight dude? It can't take a few rounds without falling apart!
Title: Re: Handheld meter electrical robustness testing.
Post by: Zbig on December 14, 2019, 01:15:57 pm
So could they really be doing no cold junction compensation at all? The Temp mode really appears to just read the DCmV and translate this to temperature using a LUT, though a LUT that gives much more resolution than the one for the NTC sensor.

The cold junction compensation done on multimeters is to add the ambient temperature to the thermocoupler temperature and the ambient is often measured inside the multimeter chip, i.e. a long way from the correct location. This also means a multimeter may need one to two hours at a specific temperature before the internal sensor matches the actual cold junction.

Just to rephrase HKJ's response, there is little point speculating whether a thermocouple-based temperature measurement function in a multimeter uses cold junction compensation or not. As long as it doesn't show "0" every time the probe is in the same environment (same temperature) as the meter itself, then of course it does. In this scenario, both ends of the thermocouple (that is the "tip" and the whole length of wire) being the same temperature, i.e. with zero temperature gradient, the probe produces a voltage of zero. So there really is no lazy, cut-corners way of implementing a thermocouple-based temperature measurement with the cold-junction compensation omitted altogether. Of course it doesn't stop you from implementing it improperly.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 02:16:21 pm
Destructive testing and final thoughts.  There's a joke in there somewhere.....

https://www.youtube.com/watch?v=dvV6pf1yaUs (https://www.youtube.com/watch?v=dvV6pf1yaUs)
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 14, 2019, 04:41:43 pm
 :-DD  Good job , so those 2 small SMD transistors for resistance protection are far worse than 2 x 1N4007 ... without further modifications . When you look at the schematic in series is just the thermistor ( 1K2) + 1K resistor + 100ohm SMD resistor the one that probably burned . The thermistor has a time lag to heat up and increase its resistance .

So the switch for how many cycles do you think will be good ?
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 14, 2019, 04:59:56 pm
There's a joke in there somewhere.....

I watched it all but I didn't hear any jokes. Anybody...?

Title: Re: Handheld meter electrical robustness testing.
Post by: Dr. Frank on December 14, 2019, 05:42:35 pm
Provided that Dave really has replaced these two 1N4007 by the reversed transistor diodes pair, (aka  FLUKE protection), which he had promoted in two of his former videos, my prediction that this was useless, and the wrong approach, obviously has come true, as the Ohm range was far off after the overload experiments by Joe.

I'm no real friend of Joes further brutal destructive tests, as they seem to me being exaggerated and not conforming to the IEC et.al. test standards.

But anyhow, the 121GW really has big problems not to detect AC+DC signal overloads.
This has been discovered already when AC+DC current overloads were investigated in another thread.

So this is really a safety issue at high voltages, which should be solved by UEI.
Hopefully this can be done in SW, but I fear that this might be an intrinsic problem of the circuit, or of the chip set, precisely, of the way how AC signals were measured.

Frank
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 05:50:45 pm
There's a joke in there somewhere.....

I watched it all but I didn't hear any jokes. Anybody...?

I doubt anyone can top the 121 for a joke. 

:-DD  Good job , so those 2 small SMD transistors for resistance protection are far worse than 2 x 1N4007 ... without further modifications . When you look at the schematic in series is just the thermistor ( 1K2) + 1K resistor + 100ohm SMD resistor the one that probably burned . The thermistor has a time lag to heat up and increase its resistance .

So the switch for how many cycles do you think will be good ?
 

I am looking at the meter today.  The contacts that were damaged were #1 & #7 which is for the two PTCs used for LZ mode.  That bank was not selected and the wimpy little transient generator jumped it.   I'm fine with suggesting that I didn't get all the copper debris cleaned up as an excuse.   Had that not jumped, all the energy would have gone into that clamp..     R82 (100 ohm) is open.    U9 (mux) is gone.

It appears the cobbled on mezzanine clamp circuit is still fine.  Both transistors check.  Rather than the clamp saving U9, it appears U9 was what saved that clamp.   

Just looking over the board for other signs of damage, I came across this gem.   It appears C67 is a nopop, so having pin 3 of U13 lifted doesn't hurt anything.   First, I am surprised to see such skills.  Then, I'm surprised that no one caught it before it left the factory.   

A UEi and a UNI-T went on a date.  9 months later, they had a baby CEM.   
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 14, 2019, 06:07:35 pm
So should we make a guess that next hardware revision will have R82 (100 ohms) with a higher voltage rating, or perhaps higher resistance too?

And I seem to remember long long time ago Joe already predicted R82 will probably fail and it seems UEi/Dave did not get that message then, but perhaps now? - we can at least hope.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 06:21:17 pm
Provided that Dave really has replaced these two 1N4007 by the reversed transistor diodes pair, (aka  FLUKE protection), which he had promoted in two of his former videos, my prediction that this was useless, and the wrong approach, obviously has come true, as the Ohm range was far off after the overload experiments by Joe.

I'm no real friend of Joes further brutal destructive tests, as they seem to me being exaggerated and not conforming to the IEC et.al. test standards.

But anyhow, the 121GW really has big problems not to detect AC+DC signal overloads.
This has been discovered already when AC+DC current overloads were investigated in another thread.

So this is really a safety issue at high voltages, which should be solved by UEI.
Hopefully this can be done in SW, but I fear that this might be an intrinsic problem of the circuit, or of the chip set, precisely, of the way how AC signals were measured.

Frank

Hey Frank.  I shutter to think what would happen if I ran the actual surge test and that switch broke over like that.   

I was going to do some experiments with the new changes but I thought, I've already gone down that path with the prototype and here we are 2 years later....    Another problem is the video was a couple of weeks packed into an hour.    Then there is the fact that it was painfully obvious that it would not save the mux.  I had commented to a few people that I was concerned that the simple grill ignitor would take it out.  Like the shim, it just wasn't thought out.   

So should we make a guess that next hardware revision will have R82 (100 ohms) with a higher voltage rating, or perhaps higher resistance too?

And I seem to remember long long time ago Joe already predicted R82 will probably fail and it seems UEi/Dave did not get that message then, but perhaps now? - we can at least hope.

Not suggesting this is the solution but I clamped on the other side of R82.  I suspect I could have removed my TVS and both 400x and it would be fine having R82 limit the current to the mux but I never tried it.  It's not my job to design it.  I just wanted to find the next weak link in the chain.   


That 121GW has some mighty big balls,   solder balls that is....   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 14, 2019, 06:27:16 pm
Something was dammaged ( leaky ) from the grill starter ... those 2 transistors were the perfect candidats  ::) Maybe should be investigated more .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 07:30:33 pm
Something was dammaged ( leaky ) from the grill starter ... those 2 transistors were the perfect candidats  ::) Maybe should be investigated more .

You and I are thinking along the same path.  The two switch pads had  become hot enough to breakdown the adhesive.  I ground out the bad area and filled with epoxy.  I had an extra mux from my experiments with the prototype so I have replaced the damaged one.   I also replaced R82.  I then cleaned up some of the poor soldering and removed all of the clamp circuits D13, mez, Q5, MOV.  Checked all the clamps and they don't appear to have been the cause but I left them out.   After cleaning it,  I powered up the meter.    The frequency now works.  Looking at the resistance and capacitance, they are both still low.  It seems back to where it was when the grill starter had damaged it.    I doubt U16 and am suspecting the Hycon took the hit.  Not a big surprise.....   

The meter is in pretty rough shape after running the life test.  I've already spent more time with my failure analysis than I had planned.  The meter is good enough now that if we come up with some other destructive test, it should be usable. 

**************
Removing U16, the 10Meg range jumped.  A bit unexpected.  I now suspect this was from the heat.  Replaced the part, cleaned and dried.   Right back to where we started.   There is not much left and getting these controller ICs seems to be a bit of a problem.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 14, 2019, 07:52:01 pm
I think you did the thermal test  before with the prototipe , was the same ( bad ) ?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 08:29:22 pm
I think you did the thermal test  before with the prototipe , was the same ( bad ) ?

Dave was quick to point out it had a different reference.  Yes, it was a high drifter compared with the other meters I had looked at.  That UT181A was the most stable out of the group (which is why I show it).   The UT61E was also really bad.  Not sure which was worse, it or the CEM.  After I took a crack at compensating the UT61E for a few pennies and it's now one of the more stable meters I have.   

I was surprised to see the 121GW moving as much as it did.  Someone asked about the humidity which in the video, the other two meters were ran during the humid summer months.   I really dropped the temperature of the Brymen BM869s.   Then I ramped the temperature as fast as I could.   You may have seen me open the box on the UT181A to help speed things up.  Those two meters, even with that level of abuse were fairly stable at both ends.   We are nearing winter and the house is now very dry.  Static is starting to be a problem again.   I only took the 121 to -10 and ramped it in about an hour.   Fairly slow.       

https://youtu.be/mzBDgxkO3HE?t=239

*** 
Correct time stamp.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 14, 2019, 09:19:00 pm
OK , I asked if the prototipe was the same in the tests you did back then , if you did . For voltage .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 09:28:20 pm
I am not sure what you are asking then. 

I think you did the thermal test  before with the prototipe , was the same ( bad ) ?

"was the same (bad)"  Are you asking how much drift the prototype had? 

OK , I asked if the prototipe was the same in the tests you did back then , if you did . For voltage .

I did run the prototype back then.  Yes, I ran it with a constant voltage.   

It almost comes across that you are asking if the meter shown being temperature cycled in this video is the prototype meter.  If so, no it was not.  It was one of the two meters that Dave had sold me.   (actually, it was the one marked Production 1)    I ran all of the non-destructive tests on Production 1 in order to preserve it for future tests.   
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 14, 2019, 09:48:31 pm
About the grill starter test, when you tested the prototype not only did it survive but the test never seemed to reset the meter either, so that clamping design was better or more robust if you like. But here with the production meter it went into reset several times as if the voltage spike found a way in even to affect the MCU voltage rails.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 14, 2019, 09:55:50 pm
I am not sure what you are asking then. 


I ask if the prototipe is worse , better , or the same for voltage temperature stability .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 14, 2019, 10:32:53 pm
About the grill starter test, when you tested the prototype not only did it survive but the test never seemed to reset the meter either, so that clamping design was better or more robust if you like. But here with the production meter it went into reset several times as if the voltage spike found a way in even to affect the MCU voltage rails.

Keep in mind that the prototype also had a different PCB and other changes.  I can't say for certain on what change/s caused the meter to less robust than the prototype.   And mind you, I am certainly NOT suggesting that the prototype was the holy grail.  That meter wasn't even close to what I would consider being electrically robust. 

For the path of the ESD, it does appear that it may have involved the Hycon IC.  Too bad really.   It appears the mVDC and temperature functions are also dead.  mVAC is working.  I can trace the signals to the Hycon part and it seems fine.   

Beating on the prototype with the stupid grill starter.  That test started out as a bit of a joke.   
https://youtu.be/X28bwdTBW8g?list=PLZSS2ajxhiQDBDdtQNjVnGxShaVQ3nUMY&t=1013


I am not sure what you are asking then. 

I ask if the prototipe is worse , better , or the same for voltage temperature stability .

 :-DD  Now I understand.  Sometimes a hammer works best.    The ones I purchased appear to be much better.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 14, 2019, 10:49:11 pm
There's a joke in there somewhere.....
I watched it all but I didn't hear any jokes. Anybody...?
I doubt anyone can top the 121 for a joke. 

I'm more glad then ever I didn't get one. Between the firmware problems, the shims to get the selector switch to make contact with the PCB, the SD card madness, and now this... it's a disaster.

It even seems like the CAT rating could be bogus.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 14, 2019, 11:25:39 pm
There's a joke in there somewhere.....
I watched it all but I didn't hear any jokes. Anybody...?
I doubt anyone can top the 121 for a joke. 

I'm more glad then ever I didn't get one. Between the firmware problems, the shims to get the selector switch to make contact with the PCB, the SD card madness, and now this... it's a disaster.

It even seems like the CAT rating could be bogus.
Fungus, just keep in mind the CAT requires the operator survivability, not the meter. Joeqsmith's tests validate the electrical robustness. Although I suspect there is a correlation between the two.

I do the same in my videos but with much less voltage (~60Vac but on several seconds) just to show a bit of what to expect if the ranges are incorrectly selected.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2019, 12:35:49 am
There's a joke in there somewhere.....
I watched it all but I didn't hear any jokes. Anybody...?
I doubt anyone can top the 121 for a joke. 

I'm more glad then ever I didn't get one. Between the firmware problems, the shims to get the selector switch to make contact with the PCB, the SD card madness, and now this... it's a disaster.

It even seems like the CAT rating could be bogus.
Fungus, just keep in mind the CAT requires the operator survivability, not the meter. Joeqsmith's tests validate the electrical robustness. Although I suspect there is a correlation between the two.

I do the same in my videos but with much less voltage (~60Vac but on several seconds) just to show a bit of what to expect if the ranges are incorrectly selected.

To this day, I still can't tell you the correct interpretation of the safety standard.   Maybe this is why Fluke had told me outright that they designed their meters to survive.  Maybe they error to the side of making damn sure they don't injure a worker by making sure the meter survives?? Too bad the ex Fluke employee doesn't jump in.   

I don't hold a lot of stock now in these standards and seeing the 121 unable to show voltages didn't boost my confidence.   I was really surprised to see that switch contact arc over as well.  Then again, seeing that Gossen with it's latching relays and no magnetic shield...  why should I be surprised. 

You and Frank are both right in that I don't test to the IEC standards.  Looking at the meters from a safety point of view has never been a goal. 
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 15, 2019, 12:37:18 am
That temperature drift from -10 to 60C is very concerning, and what the hell is causing it.

As I've mentioned earlier 121gw specified operation temp is 0 to 50C according to the manual. I interpret this to mean within this range it should be reasonable within its specified accuracy, in all modes/ranges(?).

Dave did his own thermal test but at a 4.5000V reference, And this was with the new reference chip for the 121gw, I believe. And here drift did not really seem to be a problem:
https://www.youtube.com/watch?v=Wwz_fdU17aQ (https://www.youtube.com/watch?v=Wwz_fdU17aQ)


But in Joe’s test with a 1.000mV reference I saw a reading of 0.870mV at 0C (according to 121gw internal temp sensor) and again 0.870mV at 20.2C and then 0.909mV at 50C. Way of the specified accuracy for DCmV ±0.1% + 10 counts.

But then the meter, after being allowed to stabilize 2h in room temperature 20.2C is now showing 0.997mV.

Strangely the only time I saw 0.997mV in the thermal chamber was when internal temp was showing -18C.

I realize just because the 121gw internal sensor is showing a certain temperature doesn’t mean the rest of the meters internals is at that same temp (yet). But 0.870mV at 20.2C in the thermal chamber seems very far from 0.997mV at “room temperature” 20.2C.

I just don't get it.
Title: Re: Handheld meter electrical robustness testing.
Post by: malagas_on_fire on December 15, 2019, 12:50:55 am
The uni-t 139C is the only uni-t that have survived the minimal energy ESD  test ? Seems the ut139 series ( A/B/C/D/E/S) is more robust, but this is a line of meters behind the 121GW and this got into ESD low energy failed.. :( A nearby taser such as the electrobooomm video would put that meter down if you remember ...

 Not to curse the 121GW, but there is a lot of room for improvement....

The uni-t has another new series of meters called pro.... UT195 :

https://www.uni-trend.com/html/product/General_Meters/Digital_Multimeters/UT195/ (https://www.uni-trend.com/html/product/General_Meters/Digital_Multimeters/UT195/)

They have dual dispay but 6000 counts only... wonder iff they are built to last has they anounced ....   the ringing generator , the ESD, and transients :P




PS.: ohh was forgeting the clamp meter ut210E, the nice and compact one.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2019, 01:36:59 am
That temperature drift from -10 to 60C is very concerning, and what the hell is causing it.
...
I just don't get it.
Different parts inside the meter are changing at different rates when I ramp the box, even at this slow rate.  With this meter, it causes a fair bit of error.      I allow it to sit at the two extremes for a half hour to stabilize.  There's not a lot of room in that box and there is a decent sized fan.  At -10 we had 1.003mV, 20ish 0.997mV and 60C 0.928mV.   

But if you leave it in your car overnight in the dead of winter (much colder here than -10C) and bring it inside to use it, expect there to be a fair bit of error until it settles.  Normally we would test something like this with a shock chamber but in my home lab, you have to settle for my cardboard box.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 15, 2019, 08:37:07 am
Probably the voltage reference is shitty ... pretty obvious
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 15, 2019, 11:15:48 am
That temperature drift from -10 to 60C is very concerning, and what the hell is causing it.
...
I just don't get it.
I allow it to sit at the two extremes for a half hour to stabilize.  There's not a lot of room in that box and there is a decent sized fan.  At -10 we had 1.003mV, 20ish 0.997mV and 60C 0.928mV.   


It’s difficult to tell exactly as this part of your video is so time compressed, and is perhaps the overlayed chamber camera not really in sync, but:

121gw showing 0.899mV at -8.9c, control program (chamber temp) is shoving about 20c:
[attachimg=3]



121gw showing 0.871mV at 20.9c, control program (chamber temp) is shoving about 43c:
[attachimg=1]



121gw showing 0.997mV after 2h in 20.2c “room temperature”
[attachimg=2]



so I get 0.899mV when chamber temp is shoving about 20c and then 0.997mV at 20c “room temperature”, why the big difference?


Title: Re: Handheld meter electrical robustness testing.
Post by: e0ne199 on December 15, 2019, 01:42:47 pm
i just watched joeq's recent video about 121GW and now i kind of regret of buying it.... |O
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 15, 2019, 02:07:39 pm
I just finished watching the video and was truly dismayed by the results. It is hard to see a great featured meter failing so spectacularly under public scrutiny. Old or new design, the absence of a robust input protection takes it back to the ultra-cheap field restricted to low power electronics, which can be had by a fraction of the price - my UT61E works wonderfully for that and it is not a very good place to be.

I couldn't stop thinking what triggered UEi to stop selling handheld DMMs for a while before the 121GW was released. Did they disband their previously experienced dev team, saw the opportunity to reenter this market but couldn't hire them back and did Ctrl+C/Ctrl+V on older designs but without careful consideration? Or was it a cost cutting measure (the explanation that everyone loves to believe) and replaced greybeards with new hires at a fraction of the cost? We can only speculate, but I have seen both scenarios way too many times in the industry.
 
Oh well... Thank you for this christmas bonanza. I wish you a merry christmas as well.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2019, 03:47:53 pm
It’s difficult to tell exactly as this part of your video is so time compressed, and is perhaps the overlayed chamber camera not really in sync, but:

121gw showing 0.899mV at -8.9c, control program (chamber temp) is shoving about 20c:

121gw showing 0.871mV at 20.9c, control program (chamber temp) is shoving about 43c:

121gw showing 0.997mV after 2h in 20.2c “room temperature”

so I get 0.899mV when chamber temp is shoving about 20c and then 0.997mV at 20c “room temperature”, why the big difference?

That temperature drift from -10 to 60C is very concerning, and what the hell is causing it.
...
I just don't get it.
Different parts inside the meter are changing at different rates when I ramp the box, even at this slow rate.  With this meter, it causes a fair bit of error.      I allow it to sit at the two extremes for a half hour to stabilize.  There's not a lot of room in that box and there is a decent sized fan.  At -10 we had 1.003mV, 20ish 0.997mV and 60C 0.928mV.   

But if you leave it in your car overnight in the dead of winter (much colder here than -10C) and bring it inside to use it, expect there to be a fair bit of error until it settles.  Normally we would test something like this with a shock chamber but in my home lab, you have to settle for my cardboard box.

Yes it's VERY compressed.  There's about 6 hours of data, maybe more.  It takes several hours for that peltier setup to cool down to -10.  You get to see the last half hour, the ramp and the hold at high temp.   About 2 hours, compresses into a few seconds. 

I have a sinking feeling that you feel that if you took a 1lb metal block, placed it in your freezer, left it overnight, take it out the next day and held it in your hand that it would be warm because it was no longer in the freezer.   You don't seem to understand that there is a lag and it will take time for it to settle.   We need to consider the thermal mass of the meter.  The meter's case will provide some insulation. 

If you watched Part 5, where I was talking about the filters and showing some resistors that I had measured, I compared the 121 with some other meters.  Two meters in particular you should note were the UT181A and the highly modified UT61E.  These two meters were not allowed any warmup time before I began to log the data.  Compare them with meters that were allowed minutes to warm up prior to starting the test.    That UT61E would have normally wandered all over the place....

If I wanted to say look at the drift with temperature, where we would compare the internal sensor, I would step the chamber every 2 degs or so, and allow it to settle at each temperature for a half hour or so.   Maybe place a TC inside the meter near it's ambient sensor that we could monitor as well.   Then we could plot all of this data.   We would need to make sure we can record the 121GW's ambient sensor first.   

Someone had posted about how fast I ramp the temperature.   To them, -10 to 60 in an hour is a fast ramp.  It's interesting to hear different perspectives.   We would ramp -40 to 85 or -40 to 125C  in seconds.   Basically the mass of the DUT and the chamber where the limiting factor.   Look up a thermal shock chamber where we have two chambers running at two temperatures and a dumbwaiter running between them.
Title: Re: Handheld meter electrical robustness testing.
Post by: newbrain on December 15, 2019, 03:51:58 pm
Probably the voltage reference is shitty ... pretty obvious
Probably anything but, if it's the one (https://www.analog.com/media/en/technical-documentation/data-sheets/ADR3412_ADR3420_ADR3425_ADR3430_ADR3433_ADR3440_ADR3450.pdf) on the circuit diagram.
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 15, 2019, 05:24:53 pm
It’s difficult to tell exactly as this part of your video is so time compressed, and is perhaps the overlayed chamber camera not really in sync, but:

121gw showing 0.899mV at -8.9c, control program (chamber temp) is shoving about 20c:

121gw showing 0.871mV at 20.9c, control program (chamber temp) is shoving about 43c:

121gw showing 0.997mV after 2h in 20.2c “room temperature”

so I get 0.899mV when chamber temp is shoving about 20c and then 0.997mV at 20c “room temperature”, why the big difference?

That temperature drift from -10 to 60C is very concerning, and what the hell is causing it.
...
I just don't get it.
Different parts inside the meter are changing at different rates when I ramp the box, even at this slow rate.  With this meter, it causes a fair bit of error.      I allow it to sit at the two extremes for a half hour to stabilize.  There's not a lot of room in that box and there is a decent sized fan.  At -10 we had 1.003mV, 20ish 0.997mV and 60C 0.928mV.   

But if you leave it in your car overnight in the dead of winter (much colder here than -10C) and bring it inside to use it, expect there to be a fair bit of error until it settles.  Normally we would test something like this with a shock chamber but in my home lab, you have to settle for my cardboard box.

Yes it's VERY compressed.  There's about 6 hours of data, maybe more.  It takes several hours for that peltier setup to cool down to -10.  You get to see the last half hour, the ramp and the hold at high temp.   About 2 hours, compresses into a few seconds. 

I have a sinking feeling that you feel that if you took a 1lb metal block, placed it in your freezer, left it overnight, take it out the next day and held it in your hand that it would be warm because it was no longer in the freezer.   You don't seem to understand that there is a lag and it will take time for it to settle.   We need to consider the thermal mass of the meter.  The meter's case will provide some insulation.


I realize just because the 121gw internal sensor is showing a certain temperature doesn’t mean the rest of the meters internals is at that same temp (yet). But 0.870mV at 20.2C in the thermal chamber seems very far from 0.997mV at “room temperature” 20.2C.
 
As you can see I already mentioned there's a lag.

I still think it's strange that your chamber camera could catch 121gw showing 0.871mV at 20.9C on its internal sensor.


 
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 15, 2019, 05:45:51 pm
The thermistor measurement inside 121GW is not that good ... I see some self heating at room temperature so at low temperature could show way higher and then heating faster than the rest of the board .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2019, 05:48:28 pm
I realize just because the 121gw internal sensor is showing a certain temperature doesn’t mean the rest of the meters internals is at that same temp (yet). But 0.870mV at 20.2C in the thermal chamber seems very far from 0.997mV at “room temperature” 20.2C.
 
As you can see I already mentioned there's a lag.

I still think it's strange that your chamber camera could catch 121gw showing 0.871mV at 20.9C on its internal sensor.
Why?  Do you feel that the meter is homogeneous in regards to temperature?  There is going to be a slight temperature gradient when looking at the top of the meter near the LCD to the bottom near the leads.   While the chamber is small and offers a fair amount of air flow, as we get closer to the Peltier's output, we are going to see a different temperature than whats going to their input.   Again, one way to remove this effect is to allow everything to stabilize.   You can't take a snapshot while things are changing and expect much more than to note that things are changing...   


The thermistor measurement inside 121GW is not that good ... I see some self heating at room temperature so at low temperature could show way higher and then heating faster than the rest of the board .

At -10C the 121 was showing a much lower temperature, not higher. 
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 15, 2019, 06:08:54 pm
It even seems like the CAT rating could be bogus.
Fungus, just keep in mind the CAT requires the operator survivability, not the meter.

True, but a loud bang and a jolt in your hand can easily make you fall off a ladder with surprise (or take a step back, put your foot in a bucket, fall over and grab a busbar on your way down...)

If this meter has sparks jumping around inside and tracks being vaporized at 2000V then it's not going to be pleasant to hold in your hand when 6000V@ 3000A hits it (ie. CAT III 600V). I don't know about you but I want a lack of surprises in my tools when I'm around dangerous things.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2019, 06:35:24 pm
I don't see a way to get the 121GW to log the secondary display to the SD card but looking at the CSV file, it seems like they have some provisions to support it.  I can however log the internal temperature with BLE.   I already have a way to program temperature profiles into my meat packing box.  These two programs would need to be combined to keep everything synchronous.   

If the goal is to replicated what Dave shows, but using incremental steps in the temperature along with the reported internal temperature,  I think we should use his same temperature range and voltage level.  I see no reason why it would behave any different but we know there are some differences between the meters that were sent to me and what he had tested so maybe.


Getting back to the self heating....  It's not uncommon to let TE warmup prior to use and with some of these meters, like the 121, it does seem to move around a fair bit.   That's once of the nice things about meters like the 181A.  It seems you turn them on and they are ready to go.    Of course, I could say that about the free HF meters too.   :-DD    Plot shown is meter turned on cold, and allowed to run for a half hour.  About a 2 degree C rise.   


Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 15, 2019, 06:51:07 pm
It even seems like the CAT rating could be bogus.
Fungus, just keep in mind the CAT requires the operator survivability, not the meter.

True, but a loud bang and a jolt in your hand can easily make you fall off a ladder with surprise (or take a step back, put your foot in a bucket, fall over and grab a busbar on your way down...)
Oh, certainly so. I was just reinstating something that is an enabler of a very wide wiggle room between something that passes the independent testing and something that is seriously damaged.

If this meter has sparks jumping around inside and tracks being vaporized at 2000V then it's not going to be pleasant to hold in your hand when 6000V@ 3000A hits it (ie. CAT III 600V). I don't know about you but I want a lack of surprises in my tools when I'm around dangerous things.
But, but, but... Everyone LOVES surprises! :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 15, 2019, 07:33:01 pm
I realize just because the 121gw internal sensor is showing a certain temperature doesn’t mean the rest of the meters internals is at that same temp (yet). But 0.870mV at 20.2C in the thermal chamber seems very far from 0.997mV at “room temperature” 20.2C.
 
As you can see I already mentioned there's a lag.

I still think it's strange that your chamber camera could catch 121gw showing 0.871mV at 20.9C on its internal sensor.
Why? Do you feel that the meter is homogeneous in regards to temperature?  There is going to be a slight temperature gradient when looking at the top of the meter near the LCD to the bottom near the leads.   While the chamber is small and offers a fair amount of air flow, as we get closer to the Peltier's output, we are going to see a different temperature than whats going to their input.   Again, one way to remove this effect is to allow everything to stabilize.   You can't take a snapshot while things are changing and expect much more than to note that things are changing...   

I should perhaps have said: it take some time until the rest of the meter internals been affected by the temperatur the sensor is showing. So no of course there are temperature differences all over the PCB. And this probably change even if you just change the orientation of the meter. Turn it i.e. upside down and less heat will affect the NTC.

But still with regard to ambient temperature changes, the differences in temperatures inside the meter will change equally (or nearly equally), if, as you said, you just wait long enough for it to happen.

I can't really comment more than this as I haven't seen the thermal cycling in more real time. It would be interesting to know why this huge drift is happening though.
 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 15, 2019, 07:55:04 pm
I doubt the meters reported internal temperature has anything to do with the voltage drift.   You could possibly try and monitor a few spots inside the meter while sweeping the temperature to see what changes.  Seems like a lot of work for little gains, but I've spent time on far worse things.

Looks like it takes about a half hour to warm up.  Even after a 10min warmup I was seeing a bit of drift in the resistance measurements.  Again, pretty typical.  The odd ball is really just how stable that UNI-T UT181A is.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 15, 2019, 07:58:27 pm
Cooling spray and soldering iron , the easy way to detect such problems  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 15, 2019, 08:49:02 pm
The thermistor measurement inside 121GW is not that good ...
I think the 121GW CJC circuit is powered (thermistor) from one Vreg (VDD U1) yet the MCU's A/D is off another (VDDP U2). So that drift would be a delta between two vanilla voltage regs. The precision vref is not used. The MCU's ADC input impedance is also 50k so that contributes. The MCU also has a calibrated on-ship temp sensor.

What a pitchfork festival. Ouch  :'(
The main DCV temperature drift would be hard to track down. Even MLCC's going low value at low temperatures, can make noise increase. Have to take the meter apart with test wires out of the temp chamber and check the NJM Vregs and Vref etc. for drift
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 15, 2019, 08:52:39 pm
Looks like it takes about a half hour to warm up.  Even after a 10min warmup I was seeing a bit of drift in the resistance measurements.  Again, pretty typical.  The odd ball is really just how stable that UNI-T UT181A is.   

Yeah this is my impression too, the relatively low power consumption of the 121 is working against it here, should perhaps install a resistor in it just to burn some heat and bring it faster to (more) stable conditions. It could of course also be compensated for in software, if it has a repeatable enough behavior, I wonder if this is done in other MCU driven DMM's.

Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 15, 2019, 09:05:30 pm
Resistance could have other reasons to drift , the circuit is more complex  , voltage is important for finding the root cause .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 16, 2019, 01:32:01 pm
White: Chamber's temperature
Red: 121's reported ambient temperature
Green: 121's reported input voltage

I'm using a 1.0 volt reference rather than 4.5.  Data was logged over BLE.  The sample rate is roughly 2Hz (each 5deg step is roughly a half hour to give some frame of reference).

It's pretty much as stable as what Dave had posted using the 5V range.   Standard deviation is roughly 250uV.    Of course this is the Volt scale, not the mV where I test them.   

Notice how close the ambient tracks compared with what I previously show.   There is one major difference.  This is Production 2 which was tested to failure,  back from the dead, sort of.  Production 1 seemed to have a problem with the selector switch when I first looked at it.  I may have a look at it.  The build quality of Production 2 wasn't all the great.  Maybe there is something else wrong with it.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 16, 2019, 02:51:58 pm
So it is good for volt scale , millivolt uses that transil diode D13 . If the leakage current is significant and variable with temperature a small variable voltage divider to ground is formed with the input thermistor + resistor 1K2+1K . Of course just a theory .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 17, 2019, 11:53:17 am
So it is good for volt scale , millivolt uses that transil diode D13 . If the leakage current is significant and variable with temperature a small variable voltage divider to ground is formed with the input thermistor + resistor 1K2+1K . Of course just a theory .

I know Dave and a few others were not big on me running tests down in the mV range but I want to see how they look with low signals.  Normally, I would just short the inputs.   

It could very well be the TVS but there is a trend like we saw in the mV range.  Like you said, freeze spray would hunt that one down.    It's certainly much better than the prototype was.   
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 18, 2019, 10:45:22 pm
I can't recalibrate ... for some reason using a 10nF like in instructions result in 0.000nF readings in this range for any cap , so the only option is to reload the saved calibration . Maybe it's a bug , I tried many times even with different values , I don't think I did something wrong  :-//

Also pay attention if you try to re-calibrate the capacitance ranges.
There is no entry for zero value calibration in the small table inside the chapter ZERO OFFSET CALIBRATION.
In the big colored table, though, there is a scrambled entry, 'R1 : ', which might indicate that the first calibration point with open leads sets the offset, and the 2nd one with the nominal reference capacitor sets the gain.
That might explain CDaniels problem, that 0.000 is displayed for a 10nF capacitor, after calibration.

Frank

I'm not sure if the capacitance calibration procedure ever been properly documented, I can't find it anyway, but here is what worked for me:

First make sure you saved current calibration to the SD card.

Then you need a 1nF, 10nF and a 100nF reference cap.

Enter calibration mode, select lowest cap range and connect a 1nF cap, meter will display a value probably somewhat less than 1nF, press Setup to perform offset cal, after count down meter will still display an offset value. Now change the 1nF to a 10nF cap, press Mem to perform gain cal, after count down meter will store both offset and gain calibration and should now display 10nF.

Select next cap range and repeat the procedure but using 10nF to start with and then change it to 100nF.     

The rest of the cap ranges only seem to have gain calibration and if needed use the values from the table in the manual.

Also this procedure is probably only valid for FW 1.57 and up.

Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 19, 2019, 03:51:08 pm
Yes , is working that way , have you discovered by chance ?  ;D Weird anyways ... the offset calibration is for zeroing the meter with nothing connected for stray capacitance or whatever
Now I have the meter without D13 and recalibrated for caps ... so far is not drifting .
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 19, 2019, 05:14:27 pm
Yes , is working that way , have you discovered by chance ?  ;D Weird anyways ... the offset calibration is for zeroing the meter with nothing connected for stray capacitance or whatever
Now I have the meter without D13 and recalibrated for caps ... so far is not drifting .

Sorry I can’t reveal my sources, you know, I could tell you but then I’ll have to.....

I only re-calibrated my meter to bring the huge negative offset closer to or slightly above zero.

And I would never use it without D13 installed. D13 is essentially the only real protection it has in i.e. mV/Hz/Ohms modes. Even Joe’s grill starter would likely fry your hy3131 in an instant.

Great the cal procedure worked though.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 19, 2019, 06:11:47 pm
I knew it wasn't by chance ...  ;D
That input has in series 3x300Kohm that would drastically limit the current , not 10M like the main input but still ... and on the pcb is the place where the 2 transistors clamp could be soldered .
Anyway better to burn it , than to see that stupid drift  :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: fabrizio_fabrice on December 20, 2019, 04:13:31 am
Dr. Frank, Dcac; joeqsmith, Sleppy et al:
   
I bought a 121GW that I received about a week ago.   Today I noticed unusually poor capacitor readings (FW 2.02); now finding this capacitance discussion, I'm having buyer's remorse. 

A 100 pf cap in my meter for several hours drifted only 1-2 pf, so drift isn't the issue.   But at 67 pf, it's just way off. 

Reading between the lines, perhaps, I get the impression that it will not be possible to get reasonable sub-100 pf readings.  Since most of my work is 'portable', I do not want to drag a $10 meter along as a fix.

I'm not thrilled by the prospect of re-engineering the meter I bought to do work, nor am I qualified to do so.

What's your best suggestion?

Fabrice
_______________

I can't recalibrate ... for some reason using a 10nF like in instructions result in 0.000nF readings in this range for any cap , so the only option is to reload the saved calibration . Maybe it's a bug , I tried many times even with different values , I don't think I did something wrong  :-//

Also pay attention if you try to re-calibrate the capacitance ranges.
There is no entry for zero value calibration in the small table inside the chapter ZERO OFFSET CALIBRATION.
In the big colored table, though, there is a scrambled entry, 'R1 : ', which might indicate that the first calibration point with open leads sets the offset, and the 2nd one with the nominal reference capacitor sets the gain.
That might explain CDaniels problem, that 0.000 is displayed for a 10nF capacitor, after calibration.

Frank

I'm not sure if the capacitance calibration procedure ever been properly documented, I can't find it anyway, but here is what worked for me:

First make sure...
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 20, 2019, 11:19:16 am
Maybe you have the latest hardware without D13 that presumably doesn't drift , then you can recalibrate it if you want , you need a 1nF and a 10nF capacitor like "dcac" described . The 1nF must be extremely accurate , 1000pF , if you want pF precision . Basically every pF that this capacitor is off , add or substract from the small cap readings .
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 20, 2019, 12:27:50 pm
Dr. Frank, Dcac; joeqsmith, Sleppy et al:
   
I bought a 121GW that I received about a week ago.   Today I noticed unusually poor capacitor readings (FW 2.02); now finding this capacitance discussion, I'm having buyer's remorse. 

A 100 pf cap in my meter for several hours drifted only 1-2 pf, so drift isn't the issue.   But at 67 pf, it's just way off. 

Reading between the lines, perhaps, I get the impression that it will not be possible to get reasonable sub-100 pf readings.  Since most of my work is 'portable', I do not want to drag a $10 meter along as a fix.

I'm not thrilled by the prospect of re-engineering the meter I bought to do work, nor am I qualified to do so.

What's your best suggestion?

Fabrice
_______________

I can't recalibrate ... for some reason using a 10nF like in instructions result in 0.000nF readings in this range for any cap , so the only option is to reload the saved calibration . Maybe it's a bug , I tried many times even with different values , I don't think I did something wrong  :-//

Also pay attention if you try to re-calibrate the capacitance ranges.
There is no entry for zero value calibration in the small table inside the chapter ZERO OFFSET CALIBRATION.
In the big colored table, though, there is a scrambled entry, 'R1 : ', which might indicate that the first calibration point with open leads sets the offset, and the 2nd one with the nominal reference capacitor sets the gain.
That might explain CDaniels problem, that 0.000 is displayed for a 10nF capacitor, after calibration.

Frank

I'm not sure if the capacitance calibration procedure ever been properly documented, I can't find it anyway, but here is what worked for me:

First make sure...


Keep in mind the test leads play a major part if you measuring capacitors and you want pF accuracy or resolution. If you watch Joe’s videos when he check meters against his reference box he’s using relatively short leads and is not touching them when reading the values in the pF range.

And here he’s using a ‘double’ BNC adapter to connect the capacitor, just for the reason of taking the test leads out of the equation.
https://www.youtube.com/watch?v=7AhypTCJOTE (https://www.youtube.com/watch?v=7AhypTCJOTE)


This is really the only way to do it if you want to determine if you meter has a problem with small cap values. Also keep in mind even the BNC adapter adds 8-10pF to your reading.



Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2019, 12:58:27 pm
Dr. Frank, Dcac; joeqsmith, Sleppy et al:
   
I bought a 121GW that I received about a week ago.   Today I noticed unusually poor capacitor readings (FW 2.02); now finding this capacitance discussion, I'm having buyer's remorse. 

A 100 pf cap in my meter for several hours drifted only 1-2 pf, so drift isn't the issue.   But at 67 pf, it's just way off. 

Reading between the lines, perhaps, I get the impression that it will not be possible to get reasonable sub-100 pf readings.  Since most of my work is 'portable', I do not want to drag a $10 meter along as a fix.

I'm not thrilled by the prospect of re-engineering the meter I bought to do work, nor am I qualified to do so.

What's your best suggestion?

Fabrice

Keep in mind the test leads play a major part if you measuring capacitors and you want pF accuracy or resolution. If you watch Joe’s videos when he check meters against his reference box he’s using relatively short leads and is not touching them when reading the values in the pF range.

And here he’s using a ‘double’ BNC adapter to connect the capacitor, just for the reason of taking the test leads out of the equation.

This is really the only way to do it if you want to determine if you meter has a problem with small cap values. Also keep in mind even the BNC adapter adds 8-10pF to your reading.

Also, just note that I had shown adding that 1nF as a way get the meter above 0 so I could null it out.  This part would remain in place, the meter was nulled, then you would add the part you want to measure. 

It's too bad Dave hasn't released the older alignment procedure for the capacitance as it can be improved as I demonstrated.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2019, 01:10:40 pm
I have continued to work on the damaged 121GW (Production 2) and now have it working for the most part.

This meter was cycled from 5 deg C to 45 and back down to 5.  Sweep1 is showing the entire data set.  I was using a 1mV source.   White is the chamber's temperature, Red is the 121GW's ambient temperature and Green is the reported voltage. 

Sweep2 is looking at the voltage.  You can see as the temperature is changing how the meter responds. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2019, 01:26:27 pm
That temperature drift from -10 to 60C is very concerning, and what the hell is causing it.
...
I just don't get it.
I allow it to sit at the two extremes for a half hour to stabilize.  There's not a lot of room in that box and there is a decent sized fan.  At -10 we had 1.003mV, 20ish 0.997mV and 60C 0.928mV.   

It’s difficult to tell exactly as this part of your video is so time compressed, and is perhaps the overlayed chamber camera not really in sync, but:
...
121gw showing 0.871mV at 20.9c, control program (chamber temp) is shoving about 43c:
....
so I get 0.899mV when chamber temp is shoving about 20c and then 0.997mV at 20c “room temperature”, why the big difference?

Sweep3 is showing the temperature rising from 5C to 45C.  (Zoomed into the 20C area)  With all of the data synchronized, we can see that Production 2 is pretty much dead on with Production 1 during the rising ramp. 

Sweep4 is showing the temperature falling from 45C back to 5C.   (Zoomed into the 20C area)   If the meter were allowed enough time to settle at this temperature, the voltage would read the same. 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2019, 01:32:54 pm
Production 2's reported ambient temperature seems to track the chamber very close.   After cleaning up Production 1, I took the meter back down to -10C.  Oddly enough, it now behaves more like Production 2.   

Screenshot of camera, 121GW interface software and chamber control software.
Title: Re: Handheld meter electrical robustness testing.
Post by: fabrizio_fabrice on December 20, 2019, 03:36:12 pm
Dr. Frank, Dcac; joeqsmith, Sleppy et al:
   
I bought a 121GW that I received about a week ago.   Today I noticed unusually poor capacitor readings (FW 2.02); now finding this capacitance discussion, I'm having buyer's remorse. 

A 100 pf cap in my meter for several hours drifted only 1-2 pf, so drift isn't the issue.   But at 67 pf, it's just way off. 

Reading between the lines, perhaps, I get the impression that it will not be possible to get reasonable sub-100 pf readings.  Since most of my work is 'portable', I do not want to drag a $10 meter along as a fix.

Keep in mind the test leads play a major part if you measuring capacitors and you want pF accuracy or resolution. If you watch Joe’s videos when he check meters against his reference box he’s using relatively short leads and is not touching them when reading the values in the pF range.

And here he’s using a ‘double’ BNC adapter to connect the capacitor, just for the reason of taking the test leads out of the equation.

This is really the only way to do it if you want to determine if you meter has a problem with small cap values. Also keep in mind even the BNC adapter adds 8-10pF to your reading.

Also, just note that I had shown adding that 1nF as a way get the meter above 0 so I could null it out.  This part would remain in place, the meter was nulled, then you would add the part you want to measure. 

It's too bad Dave hasn't released the older alignment procedure for the capacitance as it can be improved as I demonstrated.   
Yes, I understand the lead/stray capacitance issue, so I used no leads.  I formed j-loops on the capacitor leads and plugged them directly into the meter.  About 1" long each.  That demonstrates a meter issue; as you say, probably calibration.  I'd better tolerate a few pf of drift or ten seconds settling time than a constant 30-40% error on a 100 pf reading.

If I understand the suggestion, other than for calibration, perhaps, there's no need for a 1.0000 nf reference capacitor: any stable cap that gets the meter to read somewhat above 0 even with test leads, would allow stable nulling if it remains connected in parallel with the test subject.  If that's correct, then a dual banana plug and jack fixture holding the cap would work and be much easier to carry than another meter.  Alternatively, a trimmer cap on the fixture to bring the reading to zero?  Even so, I'm fixing equipment rather than fixing broken gear.

It's not obvious to me that is there consensus on the cal process.  Am I wrong??  I do have a large assortment of "fully-aged" [old] caps, and could select some of various values, based on either/both an old Elenco LCR meter or a Fluke 83III, to effect re-calibration, even if not to the accuracy specs.

But this has given me an entirely new take on meter specs.  What I presumed was simple documentation error (which I'd try to correct, along with fixing bad page links), now presents the impression of perhaps being a clever way to reduce the accuracy required for a chicken dinner.  :clap:

I'm retired, and reflect on the high-end gear I saw discarded through corporate bankruptcy, take-overs, and downsizing to zero.  So much equipment and so fully depreciated that they were not even trying to monetize it.  I condemn my own lack of foresight.  My only defense is that I didn't work the electronics, I worked the optics.   :palm:   (Is that irony?)

But I really appreciate your collective thoughts and experience, since your dedication to the subject shows it more central to your interests than mine.  So, now what?

-Fabrice
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 20, 2019, 04:06:27 pm
Joe is refering to something else , just a trick to make it work , the proper recalibration is done  as "dcac" described .
If you have LCR bridges it is easy to sort an exact 1nF and 10nF .
Just save the old calibration and read first ten times the calibration procedures from the manual  ;D
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 20, 2019, 05:29:57 pm
....

If I understand the suggestion, other than for calibration, perhaps, there's no need for a 1.0000 nf reference capacitor: any stable cap that gets the meter to read somewhat above 0 even with test leads, would allow stable nulling if it remains connected in parallel with the test subject. 
That is correct.  Try it.

If that's correct, then a dual banana plug and jack fixture holding the cap would work and be much easier to carry than another meter.  Alternatively, a trimmer cap on the fixture to bring the reading to zero?  Even so, I'm fixing equipment rather than fixing broken gear.
In the latest manual, which I am sure you have read, it states for the 10nF range it has a resolution of 10pF and an accuracy of +/-2.5% +5counts.  Of course latest firmware has a resolution of 1pF, not 10pF as the manual suggests.  If it was +5 counts or 50pF in addition to the 2.5%, seems like it still would be the same, just with a higher resolution.    That's a guess.  The manual needs to be updated. 

It's not obvious to me that is there consensus on the cal process.  Am I wrong??

There is the manual, which does not appear correct.  There is dcac's post:

Quote
Enter calibration mode, select lowest cap range and connect a 1nF cap, meter will display a value probably somewhat less than 1nF, press Setup to perform offset cal, after count down meter will still display an offset value. Now change the 1nF to a 10nF cap, press Mem to perform gain cal, after count down meter will store both offset and gain calibration and should now display 10nF.

I believe this matches the old documentation that Dave had supplied me.   Again, I am not sure why they changed the procedure other than the additional cost to perform that extra step.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 06:50:51 pm
For fun, I ran a fairly long temperature test using Production 1 after I had cleaned it up.  This is the undamaged meter that was temperature cycled in Part 6.  Again, from my post:

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2837862/#msg2837862 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2837862/#msg2837862)

I had started out at -10C.  I then stepped the temperature in 5 deg increments up to 55C, holding at each temperature for 2 hours.  I wanted to make sure the meter was somewhat stable.    I then took it back to 0C for a few hours and then took it back to 50C and finally back to 25.    About a day and a half to run.   

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 06:55:57 pm
In the last transittion from 0 to 55C, where the chamber's slew rate was not limited,  I again zoom into the 20deg C area.   Again, we see that the meter behaves very close to Production 2 as well as what was shown in Part 6.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 06:59:02 pm
A bit more interesting is that when we look at the 121's measured voltage, it's not linear.  Once we get above 30C or so the error starts to increase.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 07:12:54 pm
Looking at the 121's measured voltage during the transitions between the two extremes, we can see the most error.   I wouldn't be too surprised if I actually thermally shocked it, say for example, leave the meter in the car during winter and bring it into the warm house and try to use it, we would see something worse.   The change would be less but the ramp would basically be the thermal mass of the meter. 

When I was trying to shock(ish) some of the other meters, that UT181A has proven to be one of the more stable meters. I doubt it has anything to do with the changes I made to improve it's front end.    It could just be an odd ball meter. 
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 21, 2019, 07:45:52 pm
And the cause for this thermal anomaly ?

By the way , shitty switch indeed , I just had to open it , clean it and resettling those contacts , resistor/cap position developed an intermitent fault , no power or reseting if I touched it . And of course the meter wasn't used much at all .
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on December 21, 2019, 07:51:39 pm
I have continued to work on the damaged 121GW (Production 2) and now have it working for the most part.

This meter was cycled from 5 deg C to 45 and back down to 5.  Sweep1 is showing the entire data set.  I was using a 1mV source.   White is the chamber's temperature, Red is the 121GW's ambient temperature and Green is the reported voltage. 

Sweep2 is looking at the voltage.  You can see as the temperature is changing how the meter responds.

[attachimg=1]

I was amazed how fast the 121 seem to react to temperature changes. So here I have taken the green mV trace, flipped it vertically and overlayed on the two temperature traces where red being 121 internal temp and white the chamber temp.

I’ve placed the time/sample axis in sync but the vertical axis for the green mV trace is now only relevant for the (inverted) trend.

As it seems the 121‘s internal temperature is lagging behind as you’d expect for the temp change to make its way through the meter casing. But the mV changes almost directly on a temperature change i.e. at the orange vertical markers I’ve placed.

Edit: correction! those two screenshots I've merged perhaps wasn't from the same sweep and therefor not in sync to begin with.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 08:54:31 pm
And the cause for this thermal anomaly ?

By the way , shitty switch indeed , I just had to open it , clean it and resettling those contacts , resistor/cap position developed an intermitent fault , no power or reseting if I touched it . And of course the meter wasn't used much at all .

I doubt I will dig into it but it could very well be one of the clamps. 

Sorry to hear about the switch failing.  What was your switch,
1) single dimple on all contacts
2) double dimple on outside contacts, single on inner
3) double dimple on all contacts

Platted?  Shim orientation?  Shimless with thin PCB?     Shimless with thick PCB? 

So many to choose from.. :-DD
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 09:23:34 pm
I was amazed how fast the 121 seem to react to temperature changes. So here I have taken the green mV trace, flipped it vertically and overlayed on the two temperature traces where red being 121 internal temp and white the chamber temp.
....
Edit: correction! those two screenshots I've merged perhaps wasn't from the same sweep and therefor not in sync to begin with.

Left scale is voltage, right temperature.   White is chamber temp, Red 121's ambient, Green reported voltage.  Samples are roughly at 2Hz and lag is about 170 seconds.  Of course, the time to settle is actually well over an hour in this case..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 21, 2019, 10:14:24 pm
If you want some idea how long it took to settle after that step, the total time is about 142 minutes.  The chamber took about 33 minutes to ramp.   So about 109 minutes or say about an hour and a half in this particular case.   
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 21, 2019, 10:44:43 pm
And the cause for this thermal anomaly ?

By the way , shitty switch indeed , I just had to open it , clean it and resettling those contacts , resistor/cap position developed an intermitent fault , no power or reseting if I touched it . And of course the meter wasn't used much at all .

I doubt I will dig into it but it could very well be one of the clamps. 

Sorry to hear about the switch failing.  What was your switch,
1) single dimple on all contacts
2) double dimple on outside contacts, single on inner
3) double dimple on all contacts

Platted?  Shim orientation?  Shimless with thin PCB?     Shimless with thick PCB? 

So many to choose from.. :-DD

Don't be sorry for me  ;), at this point I don't care too much and I can sort this kind of problems by myself ... This is just for science , I doubt this meter will be ever 100% functional , maybe if somebody has too much time to rewrite the firmware . Even the cap in circuit measurement is not working right , very easily fooled by the components on the board when other meters have no trouble , but no point in complaining anymore .
Some time ago I put some picture  for you , it is single dimple on all contacts with pre-installed shim . Now I put in reverse like in David's video , a little more tension on the contacts  ;D I see some wear in the plastic where is touching the pcb inside the hole and fingers .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 22, 2019, 01:28:35 am
Don't be sorry for me  ;), at this point I don't care too much and I can sort this kind of problems by myself ... This is just for science , I doubt this meter will be ever 100% functional , maybe if somebody has too much time to rewrite the firmware . Even the cap in circuit measurement is not working right , very easily fooled by the components on the board when other meters have no trouble , but no point in complaining anymore .
Some time ago I put some picture  for you , it is single dimple on all contacts with pre-installed shim . Now I put in reverse like in David's video , a little more tension on the contacts  ;D I see some wear in the plastic where is touching the pcb inside the hole and fingers .

Don't be surprised to find your pictures in some of my videos.  I saved the one's people uploaded and use them for references.  This was how I knew there had been so many changes.   

I saw where someone had Dave if they would verify the proper direction of the shim but there was no response.   With yours in the same direction as mine, it seems like Dave just placed it in upsidedown in his video.   This make sense just looking at it.   Then again, maybe some meters need that little extra preload.   :-DD

On the meter I ran, the switch was obviously in pretty poor condition after life cycling it, so I used some 600 paper and rubbed down the contacts, while they were still attached to the switch.  Basically to get them flat.  I then polished them with some 1000.   Then used some Kapton tape to make a cover for the shim and the housing.  So now it's Kapton riding on Kapton.  This brought  the preload up enough to get the switch usable.   I may measure how deep some of the grooves are in the pads.   I was surprised that some of those hadn't cut through to the fibreglass.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 23, 2019, 04:03:42 pm
I was going to attempt to look at the switch with the profilometer but the new software crashed on me several times and I eventually gave up.   
Title: Re: Handheld meter electrical robustness testing.
Post by: maxwell3e10 on December 26, 2019, 04:58:54 pm
Maybe it has already been discussed before in this thread, but I am wondering why there are no cheap Fluke clones with good electrical robustness. Most of the techniques are in plain sight. Just copy the board with big clearances, large fuses and MOVs. It may cost a few more dollars for parts, but the margin for "professional" multimeters is much larger.
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on December 26, 2019, 06:03:08 pm
Maybe it has already been discussed before in this thread, but I am wondering why there are no cheap Fluke clones with good electrical robustness. Most of the techniques are in plain sight. Just copy the board with big clearances, large fuses and MOVs. It may cost a few more dollars for parts, but the margin for "professional" multimeters is much larger.

Because:
a) There's no need, sales of unsafe meters are doing just fine.
b) Certification costs money and you're not going to sell many meters without certification marks.
c) Once a meter is certified you're not allowed to change a single component supplier or any part of your production line without going through re-certification.

I suspect (c) is a real problem for Chinese meter makers.
Title: Re: Handheld meter electrical robustness testing.
Post by: maxwell3e10 on December 26, 2019, 06:09:36 pm
They seem to have no problem putting certification stamps on existing meters, whether outright fake or just shady. With plenty of review sites and videos, it wouldn't be hard to get a reputation for real robustness with a few large protection components.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 26, 2019, 06:44:19 pm
Maybe it has already been discussed before in this thread, but I am wondering why there are no cheap Fluke clones with good electrical robustness. Most of the techniques are in plain sight. Just copy the board with big clearances, large fuses and MOVs. It may cost a few more dollars for parts, but the margin for "professional" multimeters is much larger.

Because:
a) There's no need, sales of unsafe meters are doing just fine.
b) Certification costs money and you're not going to sell many meters without certification marks.
c) Once a meter is certified you're not allowed to change a single component supplier or any part of your production line without going through re-certification.

I suspect (c) is a real problem for Chinese meter makers.
Fungus, "c" is only valid if you apply for their "listed" program (UL, TÜV, Intertek, etc.). The listing requires annual inspection to the manufacturing plant audits and process reviews. Most Chinese low cost meters do not go through that, but that does not solely explain lack of safety: several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings. It boils down to the manufacturer's reputation and seriousness.

A reasonable meter with decent safety is the UT139C.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 27, 2019, 12:18:42 am
[...] several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings. It boils down to the manufacturer's reputation and seriousness.

No- Sanwa, Hioki etc. will "design to" 61010 but never tested, no approvals, so it's another gamble. One spacings mistake and you learn why testing is done in the first place.
Using gas-tubes for protection is a known no-no because of the follow-through current that exists with real mains-transients. OVC aren't just a high-voltage blip. Once a gas-tube is lit due to a transient, you have mains to deal with afterwards and in the 1/2 cycle arc flash happens, the part explodes.
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on December 27, 2019, 12:36:36 pm
[...] several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings. It boils down to the manufacturer's reputation and seriousness.

No- Sanwa, Hioki etc. will "design to" 61010 but never tested, no approvals, so it's another gamble.
Do you work at one of these companies? If not, you can't possibly know that.

Using gas-tubes for protection is a known no-no because of the follow-through current that exists with real mains-transients. OVC aren't just a high-voltage blip. Once a gas-tube is lit due to a transient, you have mains to deal with afterwards and in the 1/2 cycle arc flash happens, the part explodes.
GDTs are useless, all of them fail exactly the same way and nobody manufactures them anymore. Oh, wait...

You want to rehash the year-old discussion (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1902686/#msg1902686) but I am not going to participate in your crazyness. Have a nice day.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2019, 05:57:40 pm
From:
https://www.eevblog.com/forum/blog/eevblog-1274-long-term-alkaline-battery-leakage-testing/msg2845334/#msg2845334 (https://www.eevblog.com/forum/blog/eevblog-1274-long-term-alkaline-battery-leakage-testing/msg2845334/#msg2845334)

Now I'm thinking that perhaps, rather than run different brands, take the most notorious brand (Duracell) and just test those to discover the best mechanism for leakage FIRST, before testing all the brands?

And maybe get a bunch of small $2 farting novelty gadgets that takes two AA's that has a small standby current. I could get dozens of these on AliExpress and run various combinations.
Product recommendations?

If Dave knows this to be a fact, why does the 121GW ship with them? 
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2019, 06:12:04 pm
[...] several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings. It boils down to the manufacturer's reputation and seriousness.

No- Sanwa, Hioki etc. will "design to" 61010 but never tested, no approvals, so it's another gamble. One spacings mistake and you learn why testing is done in the first place.
Using gas-tubes for protection is a known no-no because of the follow-through current that exists with real mains-transients. OVC aren't just a high-voltage blip. Once a gas-tube is lit due to a transient, you have mains to deal with afterwards and in the 1/2 cycle arc flash happens, the part explodes.

Let's assume that companies who design DMMs are not stupid enough to place a MOV or GTD directly across the meter's inputs.   In ALL cases where I have seen them used, there is a surge rated resistor and PTC in series with the GDT, so I am not sure where this explosion is coming from.    Maybe the following video will help you understand.  If you still feel there is a reason not to use a GDT in a DMM because of an explosion, feel free to post details on what conditions will cause this to happen. 

https://www.youtube.com/watch?v=wYCGnYglRjY (https://www.youtube.com/watch?v=wYCGnYglRjY)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2019, 06:25:15 pm
They seem to have no problem putting certification stamps on existing meters, whether outright fake or just shady. With plenty of review sites and videos, it wouldn't be hard to get a reputation for real robustness with a few large protection components.

I would like to see a list of these plenty of review sites you mention.   

Some meters I have looked at, like the 121GW for example, have MOVs, PTCs, what appears to be some sort of surge rated resistors, some sort of high speed clamp.   These other review sites you mention may just look at all of that and say it's robust but that is not what my channel shows and certainly not what this thread has been posting about for the last several years.    If I call a meter robust it's not because I think it looks robust, it's because it survived to some basic test levels. 

I would assume that more meters don't handle my basic tests is because there is a huge market for meters lots of features and a low cost no matter how robust they are.     
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on December 28, 2019, 06:27:14 pm
Let's assume that companies who design DMMs are not stupid enough to place a MOV or GTD directly across the meter's inputs.   

That assumption is mostly correct, but in a very few cases it is not.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2019, 07:12:57 pm
Maybe it has already been discussed before in this thread, but I am wondering why there are no cheap Fluke clones with good electrical robustness. Most of the techniques are in plain sight. Just copy the board with big clearances, large fuses and MOVs. It may cost a few more dollars for parts, but the margin for "professional" multimeters is much larger.

Because:
a) There's no need, sales of unsafe meters are doing just fine.
b) Certification costs money and you're not going to sell many meters without certification marks.
c) Once a meter is certified you're not allowed to change a single component supplier or any part of your production line without going through re-certification.

I suspect (c) is a real problem for Chinese meter makers.
Fungus, "c" is only valid if you apply for their "listed" program (UL, TÜV, Intertek, etc.). The listing requires annual inspection to the manufacturing plant audits and process reviews. Most Chinese low cost meters do not go through that, but that does not solely explain lack of safety: several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings.

I have been involved with projects where "c" was required but wouldn't think this was required for a DMM.  For example, say your JEDEC 4007 from company X is no longer offered, I doubt you would be required to stop production until you get your new diode certified.   Have anything to back up this statement? 

I use a HIOKI product to work on mains in CAT III.  When their sales team first showed up with it, I told them I planned to run it though the basic tests (surge, burst...) and they had no problems allowing this.   You people who think what I show in my videos is harsh testing have no idea.  When I ran that low end HIOKI DMM (which uses GDTs BTW), I was confident that it would do well based on my experience with them.   

I would have that same level of confidence if I looked at a new Fluke branded DMM.  Funny, five years ago you couldn't pay me to carry a Fluke but my own testing has changed my stance on that.   The same is true for Brymen and to some degree, Gossen.   

From time to time, people will ask me about looking at another UNI-T product.  I've looked at so many that if I procure another, I am now confident that that one of two things will happen.  The grill starter will damage it or it wouldn't survive to the levels that the small generator can put out (meaning it's not as robust as the $50 AMPROBE AM510 meter).    Where HIOKI sales were more than willing to allow me to fully test their products to the actual standards,  UNI-T had contacted me about sending me one of their new meters to review.  I explained what I do on the channel and that ended the conversation.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2019, 07:17:18 pm
Let's assume that companies who design DMMs are not stupid enough to place a MOV or GTD directly across the meter's inputs.   

That assumption is mostly correct, but in a very few cases it is not.
I had looked at I think a Tek-Power meter that had previsions to place some sort of clamp across the inputs but they were smart enough not to populate it.   

Which meters have you seen where they did this?   Did any of these have some sort of safety certification? 
****
I think the only times I have seen a GDT used in a DMM was the HIOKI, GOSSEN and that Keysight. 
Title: Re: Handheld meter electrical robustness testing.
Post by: HKJ on December 28, 2019, 08:13:58 pm
Which meters have you seen where they did this?   Did any of these have some sort of safety certification? 

The Vici VC8145 and maybe one or two others (With all the meters I have reviewed I cannot remember each one).
I believe I have posted a photo of it in on of your threads before, but it is some time ago.

Another meter I remember (UT125) had a spark gab in the PCB, it might survive your high voltage tests due to that, but a high energy fault would be bad. I believe I also posted a photo of that.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 28, 2019, 08:58:49 pm
I'm not too concerned with the bench meters but still, not too surprised its a VICI.  I seem to remember someone showing a spark gap intentionally designed into the PCB across the inputs.  That may have been yours.   I think one of the pocket meters I looked at may have been like that.    I've certainly looked at a few where I am sure it wasn't the designer's intention to have a sparkgap but it just worked out that way.   I would assume we won't find any reputable company doing this. 

Doing a search, I did see this one.
https://www.eevblog.com/forum/testgear/cheap-multimeters-sub- (https://www.eevblog.com/forum/testgear/cheap-multimeters-sub-)$20-allosun-em420a-and-bside-adm01/msg927655/#msg927655

A few times people have pointed out during my tests where a meter that broke down survived my low energy transients and they will start talking about how robust they are.  They just don't get that the 20J my jig has available is hardly much of anything when compared to a high energy CAT III fault.   I don't see too many comments like that anymore so maybe all this testing has had some small impact on the community. 
Title: Re: Handheld meter electrical robustness testing.
Post by: maxwell3e10 on December 28, 2019, 09:06:04 pm
You've probably done more testing and comparison across multiple brands than any manufacturer. Based on all that experience maybe can design your own meter with best protection features and start making it, to compete with EEVblog meter.
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 28, 2019, 10:11:39 pm
[...] several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings. It boils down to the manufacturer's reputation and seriousness.
No- Sanwa, Hioki etc. will "design to" 61010 but never tested, no approvals, so it's another gamble.
Do you work at one of these companies? If not, you can't possibly know that.

Can we stop shilling multimeters from manufacturers such as Sanwa and Hioki, that have no 61010 safety approvals, only misleading statements such as "designed to" or "conforms to" or "safety rating" or "CE" which mean nothing.
Only Uni-Trend UT139E and S have 61010 certification, the UT139ABC ETL certificate page has a bad URL, surely a little mistake. I've asked for the formal certificate.


As far as the protection circuits with GDT/spark gap, I see most are across the inputs in series with the usual 1.1kohm PTC, like in the 34401a, PM300, and with the extra 1kohm surge resistor for the Keysight handheld DMM'S.
The antique Beckman/Wavetek/Meterman/Amprobe Tech300/3000/HD110 family used 2kV GDT or spark gap directly across the multimeter's input. A bunch of Radio Shack models as well- these are all from pre-1010 era.
Only Fluke had a spark gap after the HV input resistor, back in the day when they used that instead of MOV's.

So an ionized gas tube would give different fault currents, some explosive due to follow-through current, and others much PTC smoke when on a DC bus (where GDT normally extinguishes at zero-cross on mains) where it's a long-term wiener roast due to the tube lighting up and keeping current flowing in the PTC.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 29, 2019, 03:10:19 am
As far as the protection circuits with GDT/spark gap, I see most are across the inputs in series with the usual 1.1kohm PTC, like in the 34401a, PM300, and with the extra 1kohm surge resistor for the Keysight handheld DMM'S.
The antique Beckman/Wavetek/Meterman/Amprobe Tech300/3000/HD110 family used 2kV GDT or spark gap directly across the multimeter's input. A bunch of Radio Shack models as well- these are all from pre-1010 era.
Only Fluke had a spark gap after the HV input resistor, back in the day when they used that instead of MOV's.

So an ionized gas tube would give different fault currents, some explosive due to follow-through current, and others much PTC smoke when on a DC bus (where GDT normally extinguishes at zero-cross on mains) where it's a long-term wiener roast due to the tube lighting up and keeping current flowing in the PTC.

It's very possible you will find lots of old technology that will be designed in ways that today would never be approved.   Again, any modern handheld DMM I have looked  at that uses a GDT, it  has been downstream of the surge rated resistor and PTC.   Obviously, if we want to talk about companies doing something so stupid as to place a GDT or MOV directly across the front end of a CAT III + meter, then I think there are countless other stupid design practiced that we should consider as well.   That does not mean that a GDT can not be designed into a product which is basically what you stated.   

Quote
Using gas-tubes for protection is a known no-no because of the follow-through current that exists with real mains-transients. OVC aren't just a high-voltage blip. Once a gas-tube is lit due to a transient, you have mains to deal with afterwards and in the 1/2 cycle arc flash happens, the part explodes.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 29, 2019, 03:32:51 am
You've probably done more testing and comparison across multiple brands than any manufacturer. Based on all that experience maybe can design your own meter with best protection features and start making it, to compete with EEVblog meter.

 :-DD :-DD  Your faith in my abilities is shown by your setting  the bar so low.     :-DD :-DD

A few reasons come to mind as to why I wouldn't take on the challenge.   First, I have zero interest in designing a handheld meter.   There are some really nice products out there today already.   I doubt I would live long enough to turn a profit.       

I've been playing around with making a source meter for my lab.   It gets used in some of the videos to measure the handheld meter's battery life.   I started to look at that 32-bit TI ADC. 
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 29, 2019, 09:11:33 am
For high voltage behaviour even a tiny bit of resistance ( teraohms or more ) counts very much  ... sparkgaps have very little as they are phisical gaps , MOV's and the other components obviously have much more . What do we see in the video is discharging in gases vs different dielectric materials . So for easy protection you would want a "leaky" material , obviously not desirable in long term as some degradation would occur . But for a fair test is very important that the equivalent input resistance to ground of the measuring IC is somewhat added after that 10Mohm resistor . I bet it counts very much .
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 29, 2019, 06:27:14 pm
For high voltage behaviour even a tiny bit of resistance ( teraohms or more ) counts very much  ... sparkgaps have very little as they are phisical gaps , MOV's and the other components obviously have much more . What do we see in the video is discharging in gases vs different dielectric materials . So for easy protection you would want a "leaky" material , obviously not desirable in long term as some degradation would occur . But for a fair test is very important that the equivalent input resistance to ground of the measuring IC is somewhat added after that 10Mohm resistor . I bet it counts very much .

Sorry, you lost me in those last three sentences.  You need to consider that the GDT will switch slower than the MOV.   With the dv/dt of the transients, the capacitance may dominate more than any DC leakage.       

Someone had posted about the MOVs degrading.  With all of my testing, I have yet to have one degrade to the point where I could detect it.  If you follow this link and skip forward a couple of pages, you will see where I run an over voltage test on the Fluke 87V over the course of a few days.       

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1443121/#msg1443121 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1443121/#msg1443121)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 29, 2019, 07:24:53 pm
[...] several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings. It boils down to the manufacturer's reputation and seriousness.
No- Sanwa, Hioki etc. will "design to" 61010 but never tested, no approvals, so it's another gamble.
Do you work at one of these companies? If not, you can't possibly know that.

Can we stop shilling multimeters from manufacturers such as Sanwa and Hioki, that have no 61010 safety approvals, only misleading statements such as "designed to" or "conforms to" or "safety rating" or "CE" which mean nothing.
I think what are Canadian friend doesn't realize is that some larger companies will have their own test facility.   Suggesting HIOKI never tests their designs seems rather ignorant, similar to making a blanket statement that GDTs  for protection is a known no-no.   HIOKI has been designing equipment for AC mains testing for decades.   

Normally, I would consider shilling from someone tied to the company.  I wouldn't say I give HIOKI any sort of preferential treatment but I will certainly state that this is the brand I am using/trusting on a professional basis working in CAT III.   
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 30, 2019, 04:42:41 am
If you have the agency approvals, no need to hide them. It's a selling feature.
They were not found when Dave reached out (https://www.eevblog.com/forum/testgear/sanwa-pm300-pocket-multimeter-review-teardown/msg1301527/#msg1301527) on the Sanwa PM300, beyond some ESD and EMC report. That's why I default to doubting that manufacturer's claims rather than people here being gullible. I did reach out to Sanwa again and see what they offer for approvals docs. I haven't looked at Hioki.

If you were an employer supplying multimeters for employee use, you are liable if there are no safety approvals, as OSHA requires.

Very few companies have their own accredited in-house approvals department, I have only seen it where they have enough products to keep a team busy and on payroll, compared to a rolling out a few multimeters every few years.
Title: Re: Handheld meter electrical robustness testing.
Post by: CDaniel on December 30, 2019, 07:25:36 am
Maybe for japanese market is enough and they don't care too much about the rest of the world ...  :)
Title: Re: Handheld meter electrical robustness testing.
Post by: floobydust on December 30, 2019, 07:41:36 am
Japan has a law mandating third-party conformity testing for manufacturers or importers. This is likely to prevent corruption which happens with self-declared approvals.

I looked for Hioki's approvals and it didn't look promising. A Hioki quality system CofC mentions "EU Low Voltage Directive" which doesn't smell like an overvoltage category to me. I can't find any agency approvals, certificates even for the domestic market in Japan.
Title: Re: Handheld meter electrical robustness testing.
Post by: TheAmmoniacal on December 30, 2019, 09:56:41 am
Let's not confuse "electrical robustness" with safety. I have yet to see a failure mode on these meters that will hurt the user.

Giving misleading readings is the only safety issue I've seen so far - how difficult would it be to design a meter with a universal HV warning? (AC, AC, DC+AC) Some indicator telling the user if it's safe or not even if the meter can't correctly display the reading.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 30, 2019, 03:31:18 pm
Maybe for japanese market is enough and they don't care too much about the rest of the world ...  :)

I wonder that with the German market as well.   
Title: Re: Handheld meter electrical robustness testing.
Post by: 2N3055 on December 31, 2019, 09:37:37 am
EN 61010-2-033 defines electrical safety for handheld multimeters.

SAFETY REQUIREMENTS FOR ELECTRICAL EQUIPMENT 
FOR MEASUREMENT, CONTROL, AND LABORATORY USE – 

Part 2-033: Particular requirements for HAND-HELD MULTIMETERS 
and other METERS, for domestic and professional use, 
capable of measuring MAINS voltage

It is THE document where CAT category ratings are defined as applied to multimeters for measuring mains voltages....

So no, they are not muppets. I trust them much more nowadays than Fluke run by bunch of greedy creeps that are coming from the same school of management as those scumbags that are running Boeing.. You know, taking some of the best and most respected companies in the world, firing all the engineers that made those companies great and milking  the brand reputation as long they can, until they destroy it..
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 31, 2019, 05:25:39 pm
Just a couple of minor comments.

EN 61010-2-033 defines electrical safety for handheld multimeters.

SAFETY REQUIREMENTS FOR ELECTRICAL EQUIPMENT 
FOR MEASUREMENT, CONTROL, AND LABORATORY USE – 

The above is from Part 1: General requirements of 61010-1.

Part 2-033: Particular requirements for HAND-HELD MULTIMETERS 
and other METERS, for domestic and professional use, 
capable of measuring MAINS voltage

The test leads come up from time to time.  These are covered in 61010-031.

It is THE document where CAT category ratings are defined as applied to multimeters for measuring mains voltages....

So no, they are not muppets. I trust them much more nowadays than Fluke run by bunch of greedy creeps that are coming from the same school of management as those scumbags that are running Boeing.. You know, taking some of the best and most respected companies in the world, firing all the engineers that made those companies great and milking  the brand reputation as long they can, until they destroy it..

You're post reminds my of ave, agv, veg ...  videos where he goes off on Fluke.   In the meantime, he appears unable to understand the instructions.  Best part was him hounding on about safety while showing the hardware fuse he had installed.  I've yet to see any new Fluke branded product perform poorly against my tests.   

I think our friend in Canada believes that the lab must be accredited to obtain a CE mark and if the lab is not accredited, it's not being tested.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on December 31, 2019, 06:03:17 pm
Let's not confuse "electrical robustness" with safety. I have yet to see a failure mode on these meters that will hurt the user.

Giving misleading readings is the only safety issue I've seen so far - how difficult would it be to design a meter with a universal HV warning? (AC, AC, DC+AC) Some indicator telling the user if it's safe or not even if the meter can't correctly display the reading.
Good point.

I would hope that after all these years that you would never expect my transient tests to ever cause a meter to fail in such a way that it would hurt a user.  I would also hope by now no one would think this was ever a goal.   

I recently repaired a meter that is UL marked.  You will not find a single MOV in the meter.  It was easily damaged with the rectified 220V waveform.   Yet it has a UL mark.  The meter may very well be safe but it's certainly not what I would consider electrically robust.   

Because my hobbies don't involve any high voltage, high energy sources but I do from time to time work with sources of high voltage and low energy,  I am more interested in the EMC rather than the safety standards.  This TPI with it's very weak front end would not survive my normal use.

*****
Just to note, this company clearly is not concerned if the meter survives.  This is a different stance than what Fluke has stated and demonstrated they take  by having their meters survive.   I have often stated that for safety that I would guess that it is more about the mechanics of the meter and the case of the TPI branded SUMMIT meter appears to be one of the more solid ones I have looked at.

The fact that UL would certify the meter leads me to believe that it is not required that a meter survive.   Seeing the Gossen with it's latching relays that can easily change state and cause the meter to not display a hazardous voltage and the 121GW where it seems the firmware can also cause the meter not to display a hazardous voltage,  maybe this is also not a requirement as both of these meters are also certified.   
Title: Re: Handheld meter electrical robustness testing.
Post by: Cliff Matthews on January 01, 2020, 04:57:32 am
With 2 minutes left in the decade.. Happy New Year Joe! and everyone else!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 06, 2020, 12:51:26 pm
Happy New Year!   Hoping Australia's fires are under control soon.   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 08, 2020, 08:12:27 pm
Maybe it has already been discussed before in this thread, but I am wondering why there are no cheap Fluke clones with good electrical robustness. Most of the techniques are in plain sight. Just copy the board with big clearances, large fuses and MOVs. It may cost a few more dollars for parts, but the margin for "professional" multimeters is much larger.

Because:
a) There's no need, sales of unsafe meters are doing just fine.
b) Certification costs money and you're not going to sell many meters without certification marks.
c) Once a meter is certified you're not allowed to change a single component supplier or any part of your production line without going through re-certification.

I suspect (c) is a real problem for Chinese meter makers.
Fungus, "c" is only valid if you apply for their "listed" program (UL, TÜV, Intertek, etc.). The listing requires annual inspection to the manufacturing plant audits and process reviews. Most Chinese low cost meters do not go through that, but that does not solely explain lack of safety: several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings.

I have been involved with projects where "c" was required but wouldn't think this was required for a DMM.  For example, say your JEDEC 4007 from company X is no longer offered, I doubt you would be required to stop production until you get your new diode certified.   Have anything to back up this statement? 
I don't have anything to back your statement about "production stop due to the lack of certification". This is an exception that would probably be negotiated between the cert agency and the manufacturer. 

My experience with the marking process and audits is related to a few products (not DMMs) we were releasing in the past few years. We didn't fall for the siren songs from the cert agency (ies) as the markings didn't add value to our products, therefore I don't know how the exception would be dealt. 

Happy new year, BTW!
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 09, 2020, 03:09:29 am
Maybe it has already been discussed before in this thread, but I am wondering why there are no cheap Fluke clones with good electrical robustness. Most of the techniques are in plain sight. Just copy the board with big clearances, large fuses and MOVs. It may cost a few more dollars for parts, but the margin for "professional" multimeters is much larger.

Because:
a) There's no need, sales of unsafe meters are doing just fine.
b) Certification costs money and you're not going to sell many meters without certification marks.
c) Once a meter is certified you're not allowed to change a single component supplier or any part of your production line without going through re-certification.

I suspect (c) is a real problem for Chinese meter makers.
Fungus, "c" is only valid if you apply for their "listed" program (UL, TÜV, Intertek, etc.). The listing requires annual inspection to the manufacturing plant audits and process reviews. Most Chinese low cost meters do not go through that, but that does not solely explain lack of safety: several japanese brands (Samwa, Hioki) have excellent quality and reputation and also do not have markings.

I have been involved with projects where "c" was required but wouldn't think this was required for a DMM.  For example, say your JEDEC 4007 from company X is no longer offered, I doubt you would be required to stop production until you get your new diode certified.   Have anything to back up this statement? 
I don't have anything to back your statement about "production stop due to the lack of certification". This is an exception that would probably be negotiated between the cert agency and the manufacturer. 

My experience with the marking process and audits is related to a few products (not DMMs) we were releasing in the past few years. We didn't fall for the siren songs from the cert agency (ies) as the markings didn't add value to our products, therefore I don't know how the exception would be dealt. 

Happy new year, BTW!

I'm a little lost.  Fungus made the statement in regards to meters which I don't believe they would be held to C.  Are you asking under what circumstances we were or just merely pointing out that I did not provide any details?   

I have been involved with getting products certified for safety by UL before but nothing to do with meters.  There was nothing that would have prevented us from changing vendors during production.   

Cases where this may come up is with something a bit more critical.  Something using Rad qualified parts for example.    A story comes to mind from many years ago that made the news.   There was a company making some of the electronics for one of our missiles.  The company wasn't able to purchase some of the MilStd IC's and so they swapped in some commercial parts so they could continue production.  The customer requires the baby papers and so once they received the actual parts, they supplied the accompanied paper work.   They then stored on-site the actual parts.   Someone in the company knew what was happening and what the end product was and contacted the customer.    I want to say that was in the 80's.

****
It seems I saw it on 60 minutes.  Doing a search, I came up with the attached from "Proposed Legislation Regarding Whistleblower Protection: H.R. 2579 ..., Volume 4":   
Title: Re: Handheld meter electrical robustness testing.
Post by: rsjsouza on January 10, 2020, 06:51:46 pm
I'm a little lost.  Fungus made the statement in regards to meters which I don't believe they would be held to C.  Are you asking under what circumstances we were or just merely pointing out that I did not provide any details? 
I guess the lines were crossed somehow. I was a bit confused and understood that you were asking me to provide documental proof about an assertive I haven't made. Nevermind. It is still early in the year... :P

It seems I saw it on 60 minutes.  Doing a search, I came up with the attached from "Proposed Legislation Regarding Whistleblower Protection: H.R. 2579 ..., Volume 4":
Quite interesting story. The snippet of document you sent has a striking resemblance with the whole 737MAX brouhaha: "Today consultants and private contractors not only build projects, they regulate them."
Title: Re: Handheld meter electrical robustness testing.
Post by: Fungus on January 10, 2020, 11:59:29 pm
I'm a little lost.  Fungus made the statement in regards to meters which I don't believe they would be held to C.  Are you asking under what circumstances we were or just merely pointing out that I did not provide any details? 
I guess the lines were crossed somehow. I was a bit confused and understood that you were asking me to provide documental proof about an assertive I haven't made. Nevermind. It is still early in the year... :P

It was me who made it and it was a bit hyperbolic. Joe won't let that pass, not in this thread. :P

You can probably buy a part from a different supplier without losing your certification. Can you use a different (but similar) part? I'm not sure.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on January 11, 2020, 12:41:03 am
The internet is filled with embellishment.  I see no reason to muddy the waters in this thread.  I guess I could try and pump up the performance of the 121GW saying it didn't blow up at 14KV.  True statement, but not helpful in any way.

Quite interesting story. The snippet of document you sent has a striking resemblance with the whole 737MAX brouhaha: "Today consultants and private contractors not only build projects, they regulate them."


Back in 2015 when the internet was in a rage about Volkswagen and their practices, I was thinking what's so news worthy about this.  Yes, history does seem to repeat often...
Title: Re: Handheld meter electrical robustness testing.
Post by: dcac on January 21, 2020, 09:24:15 pm
I was amazed how fast the 121 seem to react to temperature changes. So here I have taken the green mV trace, flipped it vertically and overlayed on the two temperature traces where red being 121 internal temp and white the chamber temp.
....
Edit: correction! those two screenshots I've merged perhaps wasn't from the same sweep and therefor not in sync to begin with.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=894150)


Left scale is voltage, right temperature.   White is chamber temp, Red 121's ambient, Green reported voltage.  Samples are roughly at 2Hz and lag is about 170 seconds.  Of course, the time to settle is actually well over an hour in this case..

Thanks for the extra detailed temp sweep.

After some testing it seems much of the drift could be caused by PTC3 and/or PTC4.

On my 121gw especially PTC3 is super sensitive to just lightly touching it with my finger, perhaps raising its temp no more than 3-4C. A 1.000mV reading drops almost directly 50-60uV and when I remove my finger it slowly recovers to 1mV. Touching PTC4 has the same affect but not at all as dramatically and this in fact instead seems to increase the voltage 30uV or so.

Obviously PTC’s are temperature dependent resistance devices but I really could not make any sense of how they manage to affect the reading so much given they only changes about 75 ohms with the same influence from my finger. But one thing that could affect the reading is that these type PTC’s seems to act as true thermocouples too. Measuring the voltage over them with another meter and 121gw turned of, the PTC’s easily generate 50-60uV - again from just slightly heating them with my finger. And this voltage then sits in series with whatever you’re tying to measure with the 121gw.

But it's still unclear how PTC3 can affect mV measurement at all, even if it is generating emf voltages, the main path for mV is through PTC4 and then the triple 300k (R18-20) resistors into PB0 at hy3131 where it is then measured by the ADC. But the PTC3 path ends up in RLD on hy3131 and here it's unclear how this pin is involved in mV mode, according to available documentation, it only seems to connect to the comparator mux in the 3131, the way it's configured by UEi's firmware.

But anyway, if it is the PTC’s causing the drift, at least it can explain why the 121gw reacts so quickly to ambient temperature changes as the PTC's sits very close to the meter casing, and very close to the input jack where the temperature change probably can affect them quite easily.

Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on February 05, 2020, 06:02:19 am
The latest spreadsheet is now available on GoogleDocs here:
https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit?usp=sharing (https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit?usp=sharing)


This spreadsheet seems out of date?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on February 05, 2020, 06:09:11 pm
The latest spreadsheet is now available on GoogleDocs here:
https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit?usp=sharing (https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit?usp=sharing)


This spreadsheet seems out of date?

It's on-line now if you would like a copy.     
Title: Re: Handheld meter electrical robustness testing.
Post by: MBY on May 21, 2020, 04:12:08 am
A bit late, but I can say, every Meterman PM55 or Amprobe PM55A I have has failed.

What happens:
- Auto mode freaks out and doesn't work (a short shows an unstable high resistance for example)
- Short detect mode shows shorted
- EF (power stick) mode works
- I can't remember what Low-Z volts does
- Hi-Z voltage works
- Diode mode acts like a short
- High ohms varies from not working to usually sounding the "shorted" beeper; IIRC high ohms will not give a stable reading
- Haven't tested current

What causes this?

The only similar thing I could find was a dying battery.

I purchased a new unit after my PM55A had failed, only to find a PM55 I gave to a friend also failed. I tested a PM55 I had and it too had failed. The replacement? Well, it tested good (testing 5V in auto mode, and shorting probes, that's it...); after a month when I went to use it to test a low voltage DC circuit again, it showed low battery ... and sure enough it failed too.

I'd like to fix them but have no idea where to start or what could have failed.
I'm later still to the game, but I also had problems with the PM55A (and I have mentioned the problems with PM55A on the forum). I own two of them, one bought, one found in a trashcan (no, really!). They are utterly unreliable with constant "restarts" and who can have confidence in a meter that actually have an "reset" procedure printed on the back?

But I may have a "fix". Instead of one CR2032, try two CR2016. It seems almost like the design had two batteries in mind. Of course, this "fix" more than halves the battery life and doubles the battery replacement cost, and 6 volts may still be too much for the design. With two 3 volts button cells, the constant restarts, confusion in auto mode and such disappeared and the meters seems stable. But still, I seldom use them anymore, since I don't really have confidence in them anyway.
Title: Re: Handheld meter electrical robustness testing.
Post by: J-R on May 21, 2020, 05:30:35 am
I'm later still to the game, but I also had problems with the PM55A (and I have mentioned the problems with PM55A on the forum). I own two of them, one bought, one found in a trashcan (no, really!). They are utterly unreliable with constant "restarts" and who can have confidence in a meter that actually have an "reset" procedure printed on the back?

But I may have a "fix". Instead of one CR2032, try two CR2016. It seems almost like the design had two batteries in mind. Of course, this "fix" more than halves the battery life and doubles the battery replacement cost, and 6 volts may still be too much for the design. With two 3 volts button cells, the constant restarts, confusion in auto mode and such disappeared and the meters seems stable. But still, I seldom use them anymore, since I don't really have confidence in them anyway.

I picked up a dozen of the Amprobe AM-47 last year which is basically the same DMM, although it's possible there are minor internal differences.  $10ea and they were all new old stock, sealed, and of course the batteries were all in various states of discharge.  About half would not power on at all, a few would power on and then reset immediately in Auto mode, and the remaining worked fine for some time before starting to exhibit the classic reset behavior.

Previously I had read about the reset issue so I purposefully left a bunch of them in endless resets for quite some time and did not see any failures.

After ordering a random supply of CR2032 batteries (Sony, Maxell, Energizer), I did determine that it's really hit or miss on these.  Some were almost 3.3V out of the package while others were as low as 3.05V.  I've also seen some that test at a reasonable voltage but then drop with any load.  Even among the name brand manufacturers, many did not have any date codes to properly reference their age.

I kept a few of the DMMs for vehicles, travel bags, various home and work locations, etc.  The rest I gave out to friends and family.

Typical power draw is under 1mA, but during startup in Auto it exceeds 7.5mA, which can trigger the reset on weak batteries.  Powered off it seems to consume around 1uA.

So, I would be curious if you connected yours up to a power supply set for 3V if it would work correctly?  To eliminate any possible battery concern.
Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 10, 2020, 11:00:27 pm
If I might add a suggestion for future models to be tested, I think the Amazon Commercial 90DM610 might be an interesting candidate because of it's price, specs and availability:
https://www.amazon.com/AmazonCommercial-Count-Digital-Multimeter-CATIV/dp/B07W1BL3RH (https://www.amazon.com/AmazonCommercial-Count-Digital-Multimeter-CATIV/dp/B07W1BL3RH)

It's basically a 6k count multimeter with a similar featureset to the brymen bm235, UL listed and iec61010 compliant, but with $49,-- (currently; it's on the rise) it's about half the price of the bm235! (and maybe the cheapest UL listed/IEC61010 multimeter?)
It is a meter made by CEM afaik (DT-9562 rebranded).
I wonder if it would survive the grill igniter test  :-X

The only thing that sets the bm235 apart from this one is the manufacturers' quoted accuracy which is better for the brymen (but this is of course a paper spec, the meter you get could be more accurate)

Kiss Analog already did an interesting review on this meter (well, the previous 90DM600 model but its probably the same):
https://youtu.be/wfFG8v-RPQ8 (https://youtu.be/wfFG8v-RPQ8)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 11, 2020, 01:13:46 am
A few people wanted to see one of the newer UNI-Ts as well.   I haven't been giving much thought to testing new meters. 

Dave was posting hints about some new meter he was planning to sell but that seems to have cooled down.  Maybe if it becomes available, I will have a look. 

I watched a few of the Kiss Analog videos on meter safety.  I'll check out the one you linked.

Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 11, 2020, 01:32:02 am
Ok looking forward to that. Didn't know UniT had some new meters.
The efford&time you make to test these meters to the extreme is impressive.
And sometimes funny, when you killed that UT181A with just 1 click of the grill starter  :-DD You so much wanted to like that meter, your reaction was priceless  :-DD


In my experience it's pretty quiet in multimeterland especially on top models from the better brands. I suspect that most large brands are working on really intergrating logging/data processing, communications and maybe touchscreen etc (for instance, the fluke 289 has been 12 years on the market or so?, brymen doesnt have a real top model logging meter etc etc).
Dave's 121gw is I think one of the latest 'higher end' meters. And I think gossen replaced the series that you tested (the 300k count one), but with a similar capable model. Maybe/hopefully one without the multiple faults you've discovered  ;)
Title: Re: Handheld meter electrical robustness testing.
Post by: EEVblog on July 11, 2020, 03:13:55 am
Dave was posting hints about some new meter he was planning to sell but that seems to have cooled down.

The usual delays.
Just got an email that it will be going into UL testing very shortly and they want me to report any issue now (was supposed to have been through UL before, I guess it didn't, or they changed it for whatever reason).
Title: Re: Handheld meter electrical robustness testing.
Post by: tautech on July 11, 2020, 03:45:22 am
Dave was posting hints about some new meter he was planning to sell but that seems to have cooled down.

The usual delays.
Just got an email that it will be going into UL testing very shortly and they want me to report any issue now (was supposed to have been through UL before, I guess it didn't, or they changed it for whatever reason).
Are you brave enough to send one to Joe ?
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 11, 2020, 01:45:18 pm
Dave was posting hints about some new meter he was planning to sell but that seems to have cooled down.

The usual delays.
Just got an email that it will be going into UL testing very shortly and they want me to report any issue now (was supposed to have been through UL before, I guess it didn't, or they changed it for whatever reason).
Are you brave enough to send one to Joe ?
I don't have a problem paying for it like everyone else and would rather wait until it has been vented and is available to the general public.   
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 11, 2020, 02:28:21 pm
Ok looking forward to that. Didn't know UniT had some new meters.
The efford&time you make to test these meters to the extreme is impressive.
And sometimes funny, when you killed that UT181A with just 1 click of the grill starter  :-DD You so much wanted to like that meter, your reaction was priceless  :-DD


In my experience it's pretty quiet in multimeterland especially on top models from the better brands. I suspect that most large brands are working on really intergrating logging/data processing, communications and maybe touchscreen etc (for instance, the fluke 289 has been 12 years on the market or so?, brymen doesnt have a real top model logging meter etc etc).
Dave's 121gw is I think one of the latest 'higher end' meters. And I think gossen replaced the series that you tested (the 300k count one), but with a similar capable model. Maybe/hopefully one without the multiple faults you've discovered  ;)

Honestly, when I started watching Dave's videos, it was because of the pure entertainment of seeing him review meters.  There are so many people reviewing them now that I don't find entertaining and they lack the technical knowledge to be a good presenter.   

The KISS Analog guy seems to be doing a bit with SPICE and trying to teach some basics.  I would say he is doing a much better job than I did with my early videos.  I watched the review you linked but I didn't get much out of it.   

Look at all the protection your getting for your money..   

Protection for the meter?  Protection for the user?  The only way to know if the meter is more robust than others is to compare it.   Dave's 121GW for example uses PTCs for the loading.  We wouldn't say they are there for protection.   I suspect the Amazon CEM has a similar input as the higher end CEMs I have.  They don't take the typical 3XMOV, 2XPTC approach for what ever reason but as we have seen, more PTCs / MOVs doesn't mean more robust. 

Recently I posted having a UL cert and doesn't mean the meter is robust and I would say having a cert does not mean that the meter is safe as we saw with the problems with the 121GW and the Gossen Ultra.   
       
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2851814/#msg2851814 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2851814/#msg2851814)
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 11, 2020, 07:53:28 pm
Kiss Analog already did an interesting review on this meter (well, the previous 90DM600 model but its probably the same):

It appears the 90DM600(DT-9560) costs $86.18 and the 90DM610 (DT-9561) is $49.00.     
I have not checked CEM to see what the differences were.   I would not expect them to behave the same when tested.   
Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 11, 2020, 09:36:17 pm

It appears the 90DM600(DT-9560) costs $86.18 and the 90DM610 (DT-9561) is $49.00.     
I have not checked CEM to see what the differences were.   I would not expect them to behave the same when tested.

It was speculated that the  90DM600 is phased out in favor of the 90DM610 and therefore prices are maybe rising? (don't know what clever algorithm comes up with those prices).
But take note, the DT-9560 and DT-9561 are NOT CEM designations.
CEM has a  DT-9560 and DT-9561, but lists them as 4k count meters, whereas both 90DM600 and 90DM610 clearly are 6k counts.
So either CEM lists them wrongly, or DT-9560 and DT-9561 in amazon's designation 90DM600(DT-9560) and 90DM610 (DT-9561) are different.

Listing at CEM, where DT-9560 and DT-9561 are both 4k count meters and only the DT-9562 is a 6k count meter:
http://www.cem-instruments.com/en/Product/detail/id/1434 (http://www.cem-instruments.com/en/Product/detail/id/1434)

Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 11, 2020, 10:22:41 pm
Are you buying the 610 to compare them?   

They look like CEM products. 
Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 12, 2020, 12:01:24 am
No I don't really have the need for another 6k count meter as I already have several.
Also I live in europe, so there is at least a ~$30 charge for transport and taxes for the amazon meter, so it would come very close to the price of a bm235 (BM235 is here about ~€85).
Then the price difference becomes pretty low and the bm235 is of course a meter that has proven itself so for europeans that might be the better deal (or one of the higher brymens, they are priced pretty well here).
I think this meter is mainly a potential good deal for US based buyers on a tight budget, maybe young hobbyists that are starting with their electronics hobby (I can't see US shipping costs, but I presume it can come delivered free of charge with amazon prime or so).
I was mainly amaized at the US retail price for a UL listed/iec61010 compliant DMM (apart from whether these specs add something to the meter or not).
Normally for that price you sometimes don't even get ceramic sand filled fuses.

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 12, 2020, 12:46:54 am
No I don't really have the need for another 6k count meter as I already have several.
Also I live in europe, so there is at least a ~$30 charge for transport and taxes for the amazon meter, so it would come very close to the price of a bm235 (BM235 is here about ~€85).
Then the price difference becomes pretty low and the bm235 is of course a meter that has proven itself so for europeans that might be the better deal (or one of the higher brymens, they are priced pretty well here).
I think this meter is mainly a potential good deal for US based buyers on a tight budget, maybe young hobbyists that are starting with their electronics hobby (I can't see US shipping costs, but I presume it can come delivered free of charge with amazon prime or so).
I was mainly amaized at the US retail price for a UL listed/iec61010 compliant DMM (apart from whether these specs add something to the meter or not).
Normally for that price you sometimes don't even get ceramic sand filled fuses.

Is the DT-9561 UL listed?  I was looking on the Amazon ad and in the manual they link and did not see where it was certified.  The manual claims it meets UL... but there is no report number.   Looking at the higher priced meter, I don't see a report number.     Their pictures are not clear enough to see a UL mark.
Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 12, 2020, 01:34:33 am
Is the DT-9561 UL listed?  I was looking on the Amazon ad and in the manual they link and did not see where it was certified.  The manual claims it meets UL... but there is no report number.
You're right, that was an assumption of mine. I looked in the manual where they say it meets UL so I figured it was UL listed, but I haven't actually seen a report number or testing agency on the back of the 90DM610 (the pics on the amazon listing are generic pics)

Quote
   Looking at the higher priced meter, I don't see a report number.     Their pictures are not clear enough to see a UL mark.
No indeed it's not in the manual, but in the kiss analog video an Intertek logo and file number can be seen:
https://youtu.be/wfFG8v-RPQ8?t=516
Intertek 4007177 if my eyesight is right

I looked it up and that report number does nothing in the intertek database, but the modelnumbers DT-9560/9561/9562 do.
You get some shenzen corporation but at the trade names it says (among others) CEM and the DT-9560/9561/9562 are compliant to some standards
https://ramuk.intertekconnect.com//WebClients/ITS/DLP/products.nsf/vwSearch?SearchView&Query=FIELD%20ListHead%20Contains%20DT-9562%20or%20FIELD%20CatCode%20Contains%20DT-9562%20or%20FIELD%20Title%20Contains%20DT-9562%20or%20FIELD%20ProductInformation%20Contains%20DT-9562%20or%20FIELD%20ProductInfo%20Contains%20DT-9562&SearchOrder=1&SearchMax=1000&SearchWV=FALSE&SearchThesaurus=FALSE&SearchFuzzy=FALSE

True the amazon commercial name is not present in that list but it's pretty certain they're rebranded CEM's so I guess they are both UL listed.
My guess is the 90DM610 will have an intertek stamp on the back just as the 90DM600 has.

I have no idea why they print that number on it when it doesn't work in the intertek database and also isn't mentioned in the listings you get there.
Maybe there is more to it than what consumers can see. I have no idea how these systems work. My teacher is google here....
Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 12, 2020, 02:49:07 am
The 121GW was certified by ETL as well.   After seeing that meter pass their certification while not being able to perform a simple autorange, I have low confidence in their abilities.   

I can tell you that when I watching him open that meter up I thought, I wonder how those piss ant fuses handle CATIV fault currents at 1KV DC....   

The Brymen BM869s on the other hand actually has a UL listing.   Those large HRC fuses are not their for the fun of it. 

Personally, for me it makes little difference.  If I have to work in an industrial environment, I am not using a cheap meter.   

As I have said many times, for my low energy electronics experiments, I am far more interested in if a meter will survive some simple transients than if it is safe.   Basically, it was the whole point of this thread.   

I think we both agree now that they are made by CEM.  If you would like to see how one would stack up in my testing against all the other meters I have looked at, knowing it has nothing to do with safety,  I may pick one up at some point.   For me, it's just another CEM with the similar clamp scheme as the ones I have looked at. 
Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 12, 2020, 04:03:05 am
The 121GW was certified by ETL as well.   After seeing that meter pass their certification while not being able to perform a simple autorange, I have low confidence in their abilities.   


With the UL 61010 not being an open norm (you have to pay dearly for it, and obviously I'm to cheap for that  ;D), I don't really know what's in there, so I don't know if it's a matter of abilities or a matter of that the content and demands set out in the norm have any real competence or high set standards of quality in them.  I also don't know if its standards concerning safety or robustness or whatever; I think its mostly (all?) safety stuff, so I imagine they want to see double isolation, isolation values of the casings and such. Maybe that's why a non/bad functioning meter can perfectly pass that norm.

All I know is that DMM reviewers usually point it out if the DMM has it or not when they review a DMM.

Browsing through the Intertek database I also saw that the popular Uni-T UT-61e is UL listed. Apparently that also meets UL 61010 standards. That immediately shows that the UL61010 standard at least isn't of much use for the gas grill repair man  ;D :palm:

And in the Uni-Trend listings you can then also see that Uni-T makes products for amongst others AMPROBE, EXTECH, GRAINGER, GREENLEE, KLEIN TOOLS,  MILWAUKEE, TENMA, Southwire, VOLTCRAFT,  and BOSCH. Always interesting to see that (but not really unheard of of course)

The inside input protection of the Amazon Commercial 90DM600 as reviewed by Kiss Analog certainly looks similar with it's arrangement of PTC's and MOV's to the CEM DT9939 you've tested so indeed maybe it performs similar on that aspect.
Title: Re: Handheld meter electrical robustness testing.
Post by: sequoia on July 12, 2020, 05:12:28 am
Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.

I haven't seen 90DM610, but have played with the 90DM600 (those used to sell about $30-$40 couple months ago....Amazon pricing is grazy)

https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/ (https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/)

It would seem these are pretty much identical meters except the rotary switch has one more position on 90DM610, while 90DM600 likely is otherwise exact same meter...

Some photos including photo of the Intertek logo/number can be found here:
https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260 (https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260)

Title: Re: Handheld meter electrical robustness testing.
Post by: joeqsmith on July 12, 2020, 01:33:48 pm
The 121GW was certified by ETL as well.   After seeing that meter pass their certification while not being able to perform a simple autorange, I have low confidence in their abilities.   


With the UL 61010 not being an open norm (you have to pay dearly for it, and obviously I'm to cheap for that  ;D), I don't really know what's in there, so I don't know if it's a matter of abilities or a matter of that the content and demands set out in the norm have any real competence or high set standards of quality in them.  I also don't know if its standards concerning safety or robustness or whatever; I think its mostly (all?) safety stuff, so I imagine they want to see double isolation, isolation values of the casings and such. Maybe that's why a non/bad functioning meter can perfectly pass that norm.

All I know is that DMM reviewers usually point it out if the DMM has it or not when they review a DMM.

Browsing through the Intertek database I also saw that the popular Uni-T UT-61e is UL listed. Apparently that also meets UL 61010 standards. That immediately shows that the UL61010 standard at least isn't of much use for the gas grill repair man  ;D :palm:

And in the Uni-Trend listings you can then also see that Uni-T makes products for amongst others AMPROBE, EXTECH, GRAINGER, GREENLEE, KLEIN TOOLS,  MILWAUKEE, TENMA, Southwire, VOLTCRAFT,  and BOSCH. Always interesting to see that (but not really unheard of of course)

The inside input protection of the Amazon Commercial 90DM600 as reviewed by Kiss Analog certainly looks similar with it's arrangement of PTC's and MOV's to the CEM DT9939 you've tested so indeed maybe it performs similar on that aspect.

Odd ETL would have the UL database.  Are you sure that what you saw wasn't ETL testing the UT61E to the UL standards?  A big difference between that and having UL list it.  The more I see approved from ETL, the less I trust them for meter safety certifications.   
Title: Re: Handheld meter electrical robustness testing.
Post by: GuidoK on July 12, 2020, 02:29:41 pm

Odd ETL would have the UL database.  Are you sure that what you saw wasn't ETL testing the UT61E to the UL standards? 

You're right again. I'm looking in the Intertek database. I don't know how to look in the UL database. Didn't realize that's not the same thing, but makes sense.
So it's Intertek tested UL 61010 compliant.
And I think that also goes for the amazon commercial meters and CEM meters.

 I don't know if Intertek can be trusted for safety certifications. I guess it all depends on what exactly is written in that safety certification.
If the things written in UL 61010 are not up to the standards/expectations you have when torture testing the meters to begin with, then it's not very useful to begin with. Have you a specific feature of the UL 61010 in your mind that Intertek does not check/check properly that makes you come to your opinion that ETL or Intertek can't be trusted?

Edit:
I registred at UL and have now some acces to their database.
UT61e isn't listed, but it's predecessor, the UT-60A/B/C/D is.
Looking at the internals of the UT-60, that also looks like it doesn't have a whole lot of input protection & glass fuses:
https://oliversmith.io/technology/2009/12/27/inside-the-uni-t-ut60a-multimeter/
Maybe you can make more of it.
So I don't know if it's specifically an Intertek/ETL thing or that the UL 61010 isn't that high of a standard.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 12, 2020, 03:46:19 pm

Odd ETL would have the UL database.  Are you sure that what you saw wasn't ETL testing the UT61E to the UL standards? 

You're right again. I'm looking in the Intertek database. I don't know how to look in the UL database. Didn't realize that's not the same thing, but makes sense.
So it's Intertek tested UL 61010 compliant.
And I think that also goes for the amazon commercial meters and CEM meters.

 I don't know if Intertek can be trusted for safety certifications. I guess it all depends on what exactly is written in that safety certification.
If the things written in UL 61010 are not up to the standards/expectations you have when torture testing the meters to begin with, then it's not very useful to begin with. Have you a specific feature of the UL 61010 in your mind that Intertek does not check/check properly that makes you come to your opinion that ETL or Intertek can't be trusted?

Again, I am not trying to prove if the meters are safe.  You should take the time to read the FAQ.   The link is in the very first post.   Yes, there are things that IMO  the standards are lacking but again, I am not an expert in safety.   I've sited several examples over the years.   

If the standards don't for example consider a strong magnetic field like you may have with a magnetic hanger you would typically use in an industrial setting and a handheld meter uses latching relays that can change their state just from having the magnet pass too close to them and the designers have no feedback to know what state they are in, and this causes the meter to indicate to the operator  safe levels  rather than potentially lethal levels....  I don't need a government agency that is behind the times to tell me there is a safety problem.   

If the standards don't consider that a handheld meter's autorange may not function properly and that the meter could indicate to the operator safe levels rather than potentially lethal ones......

There are people on this site like yourself, who have an interest in DMM safety.   You may want to try posting the question in
the following thread:

https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/ (https://www.eevblog.com/forum/testgear/a-list-of-multimeters-that-do-not-appear-to-meet-their-claimed-safety-specs/)

I imagine there are forums dedicated to safety testing, for example IEEE.  That may be something for you to look into. 
Title: Re: Handheld meter robustness testing
Post by: GuidoK on July 12, 2020, 04:00:34 pm

Again, I am not trying to prove if the meters are safe.  You should take the time to read the FAQ.   
I know you're not trying to prove if the meters are safe, but you specifically write about your opinion on the integrity of Intertek/ETL organisation compared to UL, and I wonder if that makes sense or not (nofi) where it say would be different if UL had tested them or whether the UL norm (UL61010) itself doesn't meet your expectations.
Is non functioning autorange or being influenced by magnetic sources tested? (in any norm?). Maybe your expectations and assesmentcriteria of the concept of safety are way higher than is set out in these norms (they might form a very poor baseline to begin with; it's all a matter of how one's own expecations are).

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 12, 2020, 04:44:55 pm

Again, I am not trying to prove if the meters are safe.  You should take the time to read the FAQ.   
I know you're not trying to prove if the meters are safe, but you specifically write about your opinion on the integrity of Intertek/ETL organisation compared to UL, and I wonder if that makes sense or not (nofi) where it say would be different if UL had tested them or whether the UL norm (UL61010) itself doesn't meet your expectations.
Is non functioning autorange or being influenced by magnetic sources tested? (in any norm?). Maybe your expectations and assesmentcriteria of the concept of safety are way higher than is set out in these norms (they might form a very poor baseline to begin with; it's all a matter of how one's own expecations are).

Again it seems worth repeating for you:
"Yes, there are things that IMO  the standards are lacking but again, I am not an expert in safety."

If I start seeing what I consider are safety related problems with UL certified meters, I will certainly make note of them.   

I would imagine it's like any job and the experience and knowledge of the staff are going to have a big influence on the end product.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 12, 2020, 04:47:21 pm
IIRC Batteroo got (bought?) themselves a UL certificate that UL ought to be ashamed of.

I think they probably do a good job on the whole though.

Is non functioning autorange or being influenced by magnetic sources tested? (in any norm?).
UL documents cost thousands of $$$ to read, I'm not sure anybody here has actually read the complete standard.

https://standardscatalog.ul.com/ProductDetail.aspx?productId=UL61010-1

I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)

Seasoned electricians use cheap light bulbs to check for presence of lethal voltages, not fancy mulltimeters. Carry a battery pack with you to check the bulb is good before and after you test the circuit. KISS.

Title: Re: Handheld meter electrical robustness testing.
Post by: Caliaxy on July 12, 2020, 04:49:11 pm
Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.

I haven't seen 90DM610, but have played with the 90DM600 (those used to sell about $30-$40 couple months ago....Amazon pricing is grazy)

https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/ (https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/)

It would seem these are pretty much identical meters except the rotary switch has one more position on 90DM610, while 90DM600 likely is otherwise exact same meter...

Some photos including photo of the Intertek logo/number can be found here:
https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260 (https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260)

I do own 90dm610 and can confirm that the markings on the back (referring to UL and Intertek standards) are identical to the ones on the back of 90dm600 as shown in sequoia's pictures.

Currently 90dm610 is $49 and 90dm600 is $86.18 (on Amazon USA). Yes, crazy prices (still have to figure Amazon's pricing strategy....)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 12, 2020, 05:40:40 pm
I registred at UL and have now some acces to their database.
UT61e isn't listed, but it's predecessor, the UT-60A/B/C/D is.
Looking at the internals of the UT-60, that also looks like it doesn't have a whole lot of input protection & glass fuses:
https://oliversmith.io/technology/2009/12/27/inside-the-uni-t-ut60a-multimeter/
Maybe you can make more of it.
So I don't know if it's specifically an Intertek/ETL thing or that the UL 61010 isn't that high of a standard.

I would imagine it's possible for a company to have a product certified then change the design to where it would no longer pass.   Changing to a lower cost component to save money for example.    I would imagine that it's possible to have an autorange function be tested, then change the firmware and have it behave differently.   Lots of things to consider when you talk about safety. 

I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)


I would say you are wrong but again, I am not an expert.  Consider these two sections:

Quote
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage) displayed by the equipment, the display shall give an unambiguous indication whenever the value is above the maximum positive value or below the minimum negative value of the range to which the equipment is set.

Quote
After the voltage of ..... has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.

 Now do they need to be told that if the meter displays 1V when 1KV was applied after the magnetic strap was held next to it that it's a problem?  Maybe.  Do they need to be told to test for odd behaviors in the autorange?  Maybe.   Who's fault is it if they don't stumble onto a case that causes an unsafe condition?  The test house?  The body in charge of the standards?  The company who produced the product?  The designer?  The idiot in marketing that wanted the stupid feature?    I guess you get someone killed or injured and let the courts sort it out. 

I would say if you're a company and throwing your product over the wall to be tested, you're fools.     

Seasoned electricians use cheap light bulbs to check for presence of lethal voltages, not fancy mulltimeters. Carry a battery pack with you to check the bulb is good before and after you test the circuit. KISS.

I would suggest electricians, like everyone else, are not all working at the same level or on the same problems.   Their choice of tools may depend on the job requirements.   

Imagine an industrial electrician with their light bulb.... nah...   The meter I use is about $10,000 and can provide a bit more detail than a light bulb.

******
Thinking about negligence,
Say we have some product that was certified.  Everything is great.   Someone hacks the firmware and makes it available to the public.  Say they were not the brightest bulb in the fixture and their changes make the device unsafe.   Some time later, someone is killed or injured due to installing these changes.   Who is a fault?  The company making the meter?  The person who hacked the meter?  The person who installed the hack?   Maybe the person who installed the hack was some beginner who didn't know any better and they loaned the meter to the person who was harmed.   Does that get them off the hook?
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 12, 2020, 05:53:53 pm
I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)


I would say you are wrong but again, I am not an expert.  Consider these two sections:

Quote
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage) displayed by the equipment, the display shall give an unambiguous indication whenever the value is above the maximum positive value or below the minimum negative value of the range to which the equipment is set.

Quote
After the voltage of ..... has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.

OK, I'll go with wrong.

I'm not sure how to interpret "the range to which the equipment is set" in the case of an autoranging meter though.

I also don't know how they can certify 100% that there's no software bugs in the autoranging process.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 12, 2020, 06:20:30 pm
I believe the standard only refers to meter electricral breakdowns though. They want to know if the meter can create an arc flash and hurt you, they aren't concerned with the accuracy or reliability of the readings on the screen.

(please correct me if I'm wrong about that)


I would say you are wrong but again, I am not an expert.  Consider these two sections:

Quote
If a HAZARD could arise from an OPERATOR'S reliance on the value (for example, voltage) displayed by the equipment, the display shall give an unambiguous indication whenever the value is above the maximum positive value or below the minimum negative value of the range to which the equipment is set.

Quote
After the voltage of ..... has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.

OK, I'll go with wrong.

I'm not sure how to interpret "the range to which the equipment is set" in the case of an autoranging meter though.

I also don't know how they can certify 100% that there's no software bugs in the autoranging process.

The first is in the case of an over-range.  My interpretation is they want the person conducting the test to drive the meter beyond it's maximum to make sure the meter still displays some maximum value, or a warning.    Say for example you have a 1KV rated meter.  You don't want to be on say the 200V range, apply 440V and the meter displays 0V.  You expect it to read over range, to needle hammers to the dead stop, maybe it has a red LED indicating there is a some potential hazard.

Yes, that's partly my point.  Who's job is it to prove the functionality of a product and when something is missed who is at fault?   If the company knew of a fault, say for example, I knew the 121 had some problem and disclosed it and say that information was not passed onto the test house.   Does this change the game?  Who knows.   As little as I know about safety, I know even less about US law.  The DMM is a safety device.  I assume most working in this environment have the training and PPE to keep them safe regardless.  So it may not get tested in the courts.  Still.....
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 12, 2020, 06:49:21 pm
For you safety minded people,  this is a good video describing an electrician involved with an arcflash.   

https://www.youtube.com/watch?time_continue=454&v=hfnEuRA7-vo&feature=emb_logo (https://www.youtube.com/watch?time_continue=454&v=hfnEuRA7-vo&feature=emb_logo)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 12, 2020, 08:40:50 pm
Whether 90DM600 and 90DM610  are the same I don't know. Opening them up can only provide the answer ;).
I think specs and functionality from the manual are the same I believe for what I've seen.

I haven't seen 90DM610, but have played with the 90DM600 (those used to sell about $30-$40 couple months ago....Amazon pricing is grazy)

https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/ (https://www.eevblog.com/forum/testgear/amazon-commercial-90dm600-multimeter-hacks/)

It would seem these are pretty much identical meters except the rotary switch has one more position on 90DM610, while 90DM600 likely is otherwise exact same meter...

Some photos including photo of the Intertek logo/number can be found here:
https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260 (https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260)

I do own 90dm610 and can confirm that the markings on the back (referring to UL and Intertek standards) are identical to the ones on the back of 90dm600 as shown in sequoia's pictures.

Currently 90dm610 is $49 and 90dm600 is $86.18 (on Amazon USA). Yes, crazy prices (still have to figure Amazon's pricing strategy....)

Are all the specs the same except for the addition of the temperature sensor?   

I had seen their post a while back showing the markings and had made a few comments about running one at that time but there seemed to be little interest. 

https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260 (https://www.eevblog.com/forum/testgear/amazon-do-multimeters-now/msg3040260/#msg3040260)

One thing you can be sure of is that my test jigs won't care how popular a meter is or how people feel about what see when they look at them.    Saying "that's a lot of protection"  is not magically going to make it do well. 

https://youtu.be/wfFG8v-RPQ8?t=2580 (https://youtu.be/wfFG8v-RPQ8?t=2580) 

If you would like to see one ran, just let me know.
Title: Re: Handheld meter robustness testing
Post by: CDaniel on July 13, 2020, 01:56:47 pm
It looks like a 50$ meter , it is funny how easily people compare them to a Fluke  ;D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 14, 2020, 12:22:16 pm
It looks like a 50$ meter , it is funny how easily people compare them to a Fluke  ;D
I compare them all against one another.  Blue, red, yellow, black... CE, TUV, CSA, UL... CATIII, IV,  $free, $900,  none of it matters.   Few survive, some can be repaired, most are recycled.

More to your point, Fluke no mater where they were produced, have made some of the most robust meters I have looked at.   Something I would have never guessed based on my very first Fluke meter that was a little princess.    Having ran so many Brymen products, it is obvious they also know how to make very robust meters.   
Title: Re: Handheld meter robustness testing
Post by: CDaniel on July 14, 2020, 05:28:18 pm
My post was for that "review" youtube video , not  about your tests   ;D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 14, 2020, 10:56:01 pm
My post was for that "review" youtube video , not  about your tests   ;D

Most of the ones I see, they just take it out of the box and talk about how great they are.  This is normally preceded by them telling you what an expert they are in some field.    :-DD 
 

People have been concerned with damaging their meters as long as there have been meters.  Here's an article from the 50s.   Note, they don't seem to care about safety. 
Title: Re: Handheld meter robustness testing
Post by: Kosmic on July 15, 2020, 12:18:32 am
People have been concerned with damaging their meters as long as there have been meters.  Here's an article from the 50s.   Note, they don't seem to care about safety.

They were definitely not worried about safety. Got a old analog Triplett multimeter with a 6kV range.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1023576;image)

They simply put 2 x 24M resistors in series with the input mounted on some super small connectors.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1023580;image)
Title: Re: Handheld meter robustness testing
Post by: IanB on July 15, 2020, 12:21:42 am
People have been concerned with damaging their meters as long as there have been meters.  Here's an article from the 50s.   Note, they don't seem to care about safety.

From the title of "Six-Bit Meter Saver" we can assume that two silicon diodes at that time cost about 75 cents? Interesting as that would be about $7 in today's money. Not much different than the cost of an HRC fuse.
Title: Re: Handheld meter robustness testing
Post by: dcac on July 15, 2020, 12:28:48 am
I came to think of this 'safety' note in my dad's old Heathkit IM28 manual  - I think that design was from late 60s.

[attach=1]

Title: Re: Handheld meter robustness testing
Post by: CDaniel on July 15, 2020, 07:18:19 am
That meter is powered from mains and uses the "clasic" setup with the earth mains conected to chassis and ground ... like any new bench scope that will go boom if you touch the probe ground clip to a live wire
Title: Re: Handheld meter robustness testing
Post by: GuidoK on July 16, 2020, 06:14:44 am
like any new bench scope that will go boom if you touch the probe ground clip to a live wire
Wouldn't just the earth leakage breaker circuit/RCDO just trip?
What's that.... 30mA or so? Can that cause a 'boom'?
Title: Re: Handheld meter robustness testing
Post by: CDaniel on July 16, 2020, 09:30:54 am
If your house is fitted with such a device maybe ... but it is basically a transformer + relay , so not very fast for protecting active components if you work in something non insulated from mains
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 16, 2020, 09:38:57 am
like any new bench scope that will go boom if you touch the probe ground clip to a live wire
Wouldn't just the earth leakage breaker circuit/RCDO just trip?

Did they have those in the 1960s...?  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 16, 2020, 11:23:07 am
like any new bench scope that will go boom if you touch the probe ground clip to a live wire
Wouldn't just the earth leakage breaker circuit/RCDO just trip?
What's that.... 30mA or so? Can that cause a 'boom'?
We have no whole home ground fault breaker.  I believe GFIs are required in bathrooms, kitchens and in close proximity to water. 
Title: Re: Handheld meter robustness testing
Post by: GuidoK on July 16, 2020, 11:54:26 am


Did they have those in the 1960s...?  :popcorn:
I think they had in the late 60's.

But it's very easy to fit/retrofit, if there's none available it's usually (used to be) fitted on the incoming phase or incoming 3 phases, and then usually a 300mA model is fitted because of the presence of a bathroom/kitchen/washingmashine in the house; so no separate RCD's for wet and dry groups, they just take the whole; just as easy and much safer than not fitting at all on certain groups. I don't see why one would do that last one (fitting a 300ma model it on a bathroom group but leave the others completely out...)

I don't live in the US but in europe, so maybe that clouds my view on the world a bit. In my country there isn't a house that isn't retrofitted by the network providers with at least an rcd on the incoming phases. In my view that all happened here before (guesstimated) the mid 80's so at least 35 years ago.

But indeed if this rudimentary safety is not present, then don't connect the live to the ground of your scope.
Or better yet, use an extention cord/junction box that is fitted with one in your lab  ;) (might be a good addition to the eev video on what you need to start an electronics lab  ;))
I guess safety starts with understanding what kind of mains you have.

If your house is fitted with such a device maybe ... but it is basically a transformer + relay , so not very fast for protecting active components if you work in something non insulated from mains
The ground of your scope isn't an active component.
The RCD is easily fast enough to not have your ground lead in your probe melt. That is (at least according to David Jone's video) the first thing that goes when grounding the scope to live.
But you live in Romania, one of the last countries accepted by the EU. Are there still a lot of houses in your country not fitted with RCD's on the incoming phase(s)? I'm very curious on the general state of development in eastern european countries.
(and I also wonder how this is implemented in the UK, one of the most interesting countries electrically, especially with the dodgy showerheaters (only ever saw them in the UK/ireland))
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 16, 2020, 12:37:15 pm
But it's very easy to fit/retrofit  ... snip snip

Yes, but that wasn't the question.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 16, 2020, 02:16:24 pm
For the case with test equipment, I think I would rather have it in just the lab rather than risking shutting down the entire home's power.   

I wonder if this system would have detected the floating neutral.   
https://www.news.com.au/lifestyle/real-life/cause-of-12yearolds-tragic-electric-shock-revealed-after-the-child-was-left-brain-damaged/news-story/8d60948c20675e647236b2bc2e9e5a3d (https://www.news.com.au/lifestyle/real-life/cause-of-12yearolds-tragic-electric-shock-revealed-after-the-child-was-left-brain-damaged/news-story/8d60948c20675e647236b2bc2e9e5a3d)

I have heard from friends that were forced to use GFI in the kitchens, where their high efficient fridge will have enough leakage to cause a fault.   Then they loose their entire food supply. 
Title: Re: Handheld meter robustness testing
Post by: GuidoK on July 16, 2020, 03:22:00 pm
Yes, but that wasn't the question.
The answer to your question is that if you don't consider or upgrade your 1960's electricity net in the house, then you're living with 60 year old safety standards by now.
If the government/network provider doesn't make it mandatory and calculates the costs in the tariffs, you always get people that rather play with their lives for a few cents.
Not having any kind of RCD/ground-fault circuit sounds extremely ancient where I live. Sure back in the 60's people had a hairdryer and a clock, now they have hundreds of appliences plugged in. Times have changed.
If blowing up your dso is on your mind and have no RCD at all in the phase you're using/probing, use at least something like this (or better; I have no experience with this particular model; everything is RCD protected here). 10 bucks and connect all your sockets that you use in your lab to it.
https://www.amazon.co.uk/Masterplug-Single-Socket-Safety-Adaptor/dp/B000RZDNZM (https://www.amazon.co.uk/Masterplug-Single-Socket-Safety-Adaptor/dp/B000RZDNZM)
It's strange that something like this wasn't mentioned in the whole 'dont blow up your scope' eevblog video. The way I see it this would at least save the scope. Dont know what happens to your hand if you happen to touch the ground with it at that moment though....

I wonder if this system would have detected the floating neutral.   
https://www.news.com.au/lifestyle/real-life/cause-of-12yearolds-tragic-electric-shock-revealed-after-the-child-was-left-brain-damaged/news-story/8d60948c20675e647236b2bc2e9e5a3d (https://www.news.com.au/lifestyle/real-life/cause-of-12yearolds-tragic-electric-shock-revealed-after-the-child-was-left-brain-damaged/news-story/8d60948c20675e647236b2bc2e9e5a3d)
Well if you don't have any kind of RCD there is nothing detected for certain.
This is why you either want T-N-S or TT.
Chances of this happening is biggest with TN-C (earth meets neutral in switchbox), which I've never seen over here (I think it's not allowed in CENELEC countries; I live in a 50 year old house and was fitted from new with a better system than that.), but I understand is still common practice in certain areas?
This is of course a very tragic incident and should have been avoided with a proper electrical system. Did they have any kind of RCD in the phase where the power came from?

Where I live I reckon this would be impossible with any kind of RCD installed (it's way to moist over here, any copper going in the ground is probably going to trip 300mA), but I have no idea what the australian soil does. Usually if there's grass (water), there is enough conductivity to get that 300mA, but it's best to get a good, certified ground (I think the standard here is 0,6 ohm or something like that)

(edit: this maybe goes all way too far offtopic, but I am genuine concerned about peoples safety, god forbid your own child ends up in a wheelchair braindamaged due to electric shock from a neglected electrical system or a system that misses basic safety from the beginning, and of course lots of tinkerers here sometimes with a lot of knowledge, and sometimes less: invest in an isolation transformer when trying to repair mains appliences, preferably one that you can regulate voltage, helps with fault tracing )
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 16, 2020, 05:10:29 pm
(edit: this maybe goes all way too far offtopic, but I am genuine concerned about peoples safety, god forbid your own child ends up in a wheelchair braindamaged due to electric shock from a neglected electrical system or a system that misses basic safety from the beginning, and of course lots of tinkerers here sometimes with a lot of knowledge, and sometimes less: invest in an isolation transformer when trying to repair mains appliences, preferably one that you can regulate voltage, helps with fault tracing )

I'm sure many people are but it was never my intent to use this thread to discuss safety.  The problem is that it confuses people, causing them to equate the tests I have ran with safety.    This IMO places the uneducated at a higher risk, thinking products are safe when they may not be.    Because I actually have concern for peoples welfare, people who promote that these tests have anything to do with safety are normally met with some minor backlash.   

Not surprising that suggesting people use a safety related thread seems to fall by dead ears. 

I had no plans to do anymore with this thread and was unsuccessful in having Dave lock it.  So if this is the place people want to discuss safety, I will inject what little I can.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 16, 2020, 07:07:49 pm
I'm sure many people are but it was never my intent to use this thread to discuss safety.  The problem is that it confuses people, causing them to equate the tests I have ran with safety.    This IMO places the uneducated at a higher risk, thinking products are safe when they may not be. 

It's not just the product, either. Owning the best multimeter in the world doesn't make the overall process "safe".

Even on household mains you should be wearing gloves & ear/eye protection if the wires are hot.

Don't even think of going near high energy equipment without somebody else standing by with a telephone in their hand,

etc., etc.

(tie a rope around your waist so they can pull you out...)
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on July 16, 2020, 07:18:54 pm
I'm often to be seen near colleagues, with a long wooden stick in hand, just in case.

Sadly (not really), I haven't yet had the opportunity to use it...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 16, 2020, 10:54:30 pm
I'm sure many people are but it was never my intent to use this thread to discuss safety.  The problem is that it confuses people, causing them to equate the tests I have ran with safety.    This IMO places the uneducated at a higher risk, thinking products are safe when they may not be. 

It's not just the product, either. Owning the best multimeter in the world doesn't make the overall process "safe".

Even on household mains you should be wearing gloves & ear/eye protection if the wires are hot.

Don't even think of going near high energy equipment without somebody else standing by with a telephone in their hand,

etc., etc.

(tie a rope around your waist so they can pull you out...)

Again:
  As little as I know about safety, I know even less about US law.  The DMM is a safety device.  I assume most working in this environment have the training and PPE to keep them safe regardless.  So it may not get tested in the courts.  Still.....

Your brain should be your first safety device then the PPE then maybe the meter.   If your an untrained idiot, there's not much that meter is going to do to save you.   

Many years ago, I had heard about an electrician that had gone near the transformers for a factory and was vaporized.  I am not too surprised after hearing from my friends about this other worker they knew.   Having a rope or stick may not be very effective for an arcflash. 

I think I wrote about a friend who's a master electrician who never believed in PPE.   He an another worker needed to make some measurements, suited up, went in with their long poles, hooked up to the bus and the meter exploded in my friends hands.   He figures the PPE saved him that day and he became a firm believer after that.   
Title: Re: Handheld meter robustness testing
Post by: dcac on July 16, 2020, 11:45:01 pm
I hope I didn’t derail the thread - I probably should’ve mentioned the Heathkit IM28 is a mains powered meter - with really no insulation of the input jack. My thoughts was mostly the safety aspects of following that procedure and that back in those days they even ‘suggested’ something like that. But if you knew what you were doing it probably was ok to follow it. I sure hope though people at least used a suitable insulated screwdriver as 'probe extension'.

The IM28 design is from 1968 but I think my dad bought the kit in 1977 or so - it was sold here in Sweden by a small import company. The transformer could be configured for 240V but it wasn’t delivered with any EU style mains plug. The cord is three wire but the plug that sits on it now is 2 prong - so the meter is floating so to speak. I think it could steer clear of any safety norms as it was sold as a kit and could be considered a 'home built’ device.

It is still probably working fine but hasn’t been used for the last 30 years or so.

I hope this tread stays open - the safety talk is probably unavoidable - now i.e. with the 121gw's high voltage ranging problem - that is a safety problem for sure. AFAIK it has not been addressed yet - it's been 7 months now?

Title: Re: Handheld meter robustness testing
Post by: IanB on July 17, 2020, 07:28:52 am
I think I wrote about a friend who's a master electrician who never believed in PPE.   He an another worker needed to make some measurements, suited up, went in with their long poles, hooked up to the bus and the meter exploded in my friends hands.   He figures the PPE saved him that day and he became a firm believer after that.

I've seen a couple of videos where the worker making measurements put the meter itself on the end of the long pole in capture mode and then made the measurements at pole's length before retrieving the meter to view the reading. That seems to me to be eminently sensible.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on July 17, 2020, 10:14:54 am
Your brain should be your first safety device then the PPE then maybe the meter.   If your an untrained idiot, there's not much that meter is going to do to save you.   

Many years ago, I had heard about an electrician that had gone near the transformers for a factory and was vaporized.  I am not too surprised after hearing from my friends about this other worker they knew.   Having a rope or stick may not be very effective for an arcflash. 

I think I wrote about a friend who's a master electrician who never believed in PPE.   He an another worker needed to make some measurements, suited up, went in with their long poles, hooked up to the bus and the meter exploded in my friends hands.   He figures the PPE saved him that day and he became a firm believer after that.

Just so. A rope or stick won't be much use when you're working with intermediate or high voltages.

The highest energy systems I have to deal with at work are low voltage customer end, so 400VAC 3ph and generally fused at no more than 1250A.
A wooden stick is more a humorous reminder for people (mainly but not always apprentices) to be careful or I'll beat them even more senseless than the shock they get.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 17, 2020, 11:52:18 am
I think I wrote about a friend who's a master electrician who never believed in PPE.   He an another worker needed to make some measurements, suited up, went in with their long poles, hooked up to the bus and the meter exploded in my friends hands.   He figures the PPE saved him that day and he became a firm believer after that.

I've seen a couple of videos where the worker making measurements put the meter itself on the end of the long pole in capture mode and then made the measurements at pole's length before retrieving the meter to view the reading. That seems to me to be eminently sensible.

Not being there, I am not sure why they worked this way.  Maybe the procedure called for it or the meter had too small of a display to read through the face protection at any distance.  It's possible the procedures changed after that.   Now days, I would imagine the panels allow remote monitoring.  Or they have meters built into the pole with an RF link.   I can't imagine in that video above where the guy puts his handheld on a 2KV bus like they show.   

Just so. A rope or stick won't be much use when you're working with intermediate or high voltages.

The highest energy systems I have to deal with at work are low voltage customer end, so 400VAC 3ph and generally fused at no more than 1250A.
A wooden stick is more a humorous reminder for people (mainly but not always apprentices) to be careful or I'll beat them even more senseless than the shock they get.


I want to say the above was a 4KV and the one I was told where the workers body was vaporized was also at 4KV.   In that case where the worker was killed, a second worker almost lost their life as well from that arcflash.     

I'm not sure with the case involving the larger outside transformers but imagine those are upward of 10KV off the pole. I really don't know.  I heard there were two others with him but I was unable to find any details on what happened.  I knew people that worked at that plant who had told me about it.   

On your 400V lines, do you send your workers out with lightbulbs as Fungus suggests?   I just don't envision workers with their lightbulbs and free HF meters even in these environments.       
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 17, 2020, 12:07:29 pm
I hope I didn’t derail the thread - I probably should’ve mentioned the Heathkit IM28 is a mains powered meter - with really no insulation of the input jack. My thoughts was mostly the safety aspects of following that procedure and that back in those days they even ‘suggested’ something like that. But if you knew what you were doing it probably was ok to follow it. I sure hope though people at least used a suitable insulated screwdriver as 'probe extension'.

The IM28 design is from 1968 but I think my dad bought the kit in 1977 or so - it was sold here in Sweden by a small import company. The transformer could be configured for 240V but it wasn’t delivered with any EU style mains plug. The cord is three wire but the plug that sits on it now is 2 prong - so the meter is floating so to speak. I think it could steer clear of any safety norms as it was sold as a kit and could be considered a 'home built’ device.

It is still probably working fine but hasn’t been used for the last 30 years or so.

I hope this tread stays open - the safety talk is probably unavoidable - now i.e. with the 121gw's high voltage ranging problem - that is a safety problem for sure. AFAIK it has not been addressed yet - it's been 7 months now?

We were on the safety kick before your post.  As I said, no problem.  I agree that we are much more sensitive about safety now.   I found a website that listed worker related deaths that went back several decades.   Many of the early deaths were linemen who died by electrocution.   At one point in the data, it was like someone through a switch and linemen stopped dying. 
   
The Gossen Ultra as far as I know is still sensitive to the magnetic field from a hanger.   While someone wrote me how they had added a shield similar to what I show in my videos, I have not confirmed this.  How many years ago was this?   

I like the idea of that noncontact voltage clamp that Fluke has.  Yea, I know that ave avg guy was really going off on it but still, if you could take measurements like this without having exposed conductors it would seem to be more safe.  For the most part the technology seems to work but like other meters I have looked at, there are cases where it provides bad data.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 17, 2020, 12:27:13 pm
Don't forget your proving unit to make sure your meter/tester is working before and after you test your AC circuit.

eg. https://www.fluke.com/en/product/electrical-testing/basic-testers/fluke-prv240fs-proving-unit (https://www.fluke.com/en/product/electrical-testing/basic-testers/fluke-prv240fs-proving-unit)

[attachimg=1]

I'm sure there's a 400V proving unit out there somewhere.


---------------

Edit: Yep. This one goes up to 690V and can even light up your light bulbs for you :-)

https://martindale-electric.co.uk/product/martindale-pd690sx-50v-120v-230v-440v-690v-ac-calcheck-proving-unit/ (https://martindale-electric.co.uk/product/martindale-pd690sx-50v-120v-230v-440v-690v-ac-calcheck-proving-unit/)
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on July 17, 2020, 01:57:20 pm
I want to say the above was a 4KV and the one I was told where the workers body was vaporized was also at 4KV.   In that case where the worker was killed, a second worker almost lost their life as well from that arcflash.     

I'm not sure with the case involving the larger outside transformers but imagine those are upward of 10KV off the pole. I really don't know.  I heard there were two others with him but I was unable to find any details on what happened.  I knew people that worked at that plant who had told me about it.   

On your 400V lines, do you send your workers out with lightbulbs as Fungus suggests?   I just don't envision workers with their lightbulbs and free HF meters even in these environments.       

Here in the UK the main grid runs between 100kV to 400kV. Distribution stations drop that to 11kV, then local substations drop that to the 400V we work on.

If one of my colleagues tried to use such a method, I'd have them removed from site.
Title: Re: Handheld meter robustness testing
Post by: bd139 on July 17, 2020, 03:42:20 pm
My electrician doesn’t even have a multimeter so this sort of stuff doesn’t surprise me  :palm:

I have made the odd 1-2kv reading by soldering the probes to the DUT  :-DD
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on July 17, 2020, 04:39:37 pm
@bd139 A domestic electrician doesn't need a multimeter.

They do need a 2-probe tester. I use a Fluke T5-1000, many others are available.

They also may need an installation tester, unless they're getting another sparks to sign off their work. We use Kewtech KT65s for that.

For some things I might need my Fluke 87V, or for DCA my Mastech 2108A.

I might use my Fluke VoltAlert (voltstick) for some basic safety checks, there are specific circumstances that make that acceptable or not.

Soldering leads to a DUT for 1kV measurements is quite a sensible option, given that I know you're competent at not electrocuting yourself.
Title: Re: Handheld meter robustness testing
Post by: bd139 on July 17, 2020, 05:01:11 pm
He has the steaming remains of a megger equivalent of the kewtech but i actually had to strip it and repair it for him a couple of years back as the batteries leaked in it. Haven’t seen it since. I do the work. He signs it off  :-DD. Nothing notifiable has been done since then though.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 17, 2020, 11:03:15 pm
https://www.fluke.com/en-us/learn/online-courses/electrical-measurement-safety (https://www.fluke.com/en-us/learn/online-courses/electrical-measurement-safety)

Quote
This free, self-paced, online course describes the electrical dangers you may face in the workplace, the safety standards to protect you and the best practices involved with test tool safety.

Making a mistake while working on a high-energy electrical system can deliver a deadly blow to anyone who fails to take the right safety precautions. That’s why, at Fluke Corporation, your safety is our top priority.
[/i]

I'm guessing some of those interested in safety have attended this.   If you have, what did you learn?  Was it worth the 4 hours?   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 17, 2020, 11:25:26 pm
This is for that ave agv ?? guy who was blabbing about safety all the while showing his hardware fuse installed.  Too stupid to buy the right one.  Worse, people watch this stuff and may actually believe the guy knows what he's doing.   

https://youtu.be/IzwN8yibjjA?t=879

10KA fuses getting lit up:
https://youtu.be/IzwN8yibjjA?t=682

This stuff never gets old: 
https://youtu.be/IzwN8yibjjA?t=1022

Who makes this meter???
https://youtu.be/IzwN8yibjjA?t=1073
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 17, 2020, 11:41:36 pm
Let me just get my light bulb out and check that circuit...   Nothing like an arcflash test
https://www.youtube.com/watch?v=3XJ56aHWk7k (https://www.youtube.com/watch?v=3XJ56aHWk7k)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 17, 2020, 11:48:54 pm
Of course, I play with lightbulbs at home from time to time. 
https://youtu.be/aaZxWMgOz70?t=423
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on July 18, 2020, 09:21:38 am
This is for that ave agv ?? guy who was blabbing about safety all the while showing his hardware fuse installed.  Too stupid to buy the right one.  Worse, people watch this stuff and may actually believe the guy knows what he's doing.

Are you referring to AvE?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 18, 2020, 03:30:38 pm
This is for that ave agv ?? guy who was blabbing about safety all the while showing his hardware fuse installed.  Too stupid to buy the right one.  Worse, people watch this stuff and may actually believe the guy knows what he's doing.

Are you referring to AvE?

Yeah, that's the guy.   I used that example in one of my videos where I zoomed in to show the part number and I think I went over the datasheet for it.   If you are going to talk about safety,   at least have the common sense to order the correct fuse for the meter after you blow one out.

****
I looked for their original video and was unable to find it.   As I said, I had used that part in another video I made which can be seen here:

https://youtu.be/nXjVc4Rmg7Y?t=3104

****
See attached screen captures taken from their original video.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on July 18, 2020, 04:24:41 pm
Joe, good video from Fluke. I'll watch it later.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 18, 2020, 05:48:01 pm
Joe, good video from Fluke. I'll watch it later.

Looks like they want you to provide them with your information to watch their safety course.  If you decide to watch this series, I'm interested in hearing what your take is on it. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 30, 2020, 11:38:52 pm
I pulled this old junk meter from the trash bin.  It's missing the case.  The small glass filled fuse appears original.  The large fuse was missing.  I installed a smaller fuse to test it out and it appears 100% functional.    Shown at 10V, 1V and 1.0mV.

The board is marked
Fluke 7x-3001
REV L
E-2 (hand written)
CAD 585
REV L

Main IC is marked
FLUKE O
683052
22 84
L 255


It uses spark gaps for the primary clamps.  I doubt it would hold up very well to my transient tests but it seems to have had a useful life.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 07, 2020, 11:55:50 pm
Finally got around to running the Fluke 77 from the trash bin.   

https://www.youtube.com/watch?v=IZ9tNjC7PI0 (https://www.youtube.com/watch?v=IZ9tNjC7PI0)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 09, 2020, 01:22:47 am
So far there have been a few suggestions on what to do with the meter before it heads back to trash bin.  One was life cycle the rotary switch.   If I had the case, I would have set this up.  Another was to run ESD tests on it.  My plan is to replace the damaged resistor and run that test.   Maybe then see if swapping out a few parts will allow the meter to survive to some higher levels.   Obviously, this is all dependent on if anything else was damaged, if it survives ESD, etc.   

So stay tuned for round II.   If you have anything you would like to see done with it, feel free to leave a comment.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 10, 2020, 11:44:13 am
Part II.  Enjoy.
https://www.youtube.com/watch?v=1YYvr_qe4Tw (https://www.youtube.com/watch?v=1YYvr_qe4Tw)
Title: Re: Handheld meter robustness testing
Post by: bd139 on September 10, 2020, 12:19:43 pm
Interesting. I haven't watched Part II yet. The rotary switch is trouble on these older meters IMHO. I had a 77 for years (which was my father's before) which wore out eventually and caused problems. Also I got a Fluke 25 recently that the previous dum dum owner had blown up where the switch had actually melted and buckled.

Some graphic stupidity. Fuse go bang? Yeah it was supposed to. This is not the correct solution  :palm: :palm: :palm:

(https://imgur.com/RmnVMvm.jpg)

Ahh fuse replaced, now switch go bang. I've removed the top layer of wafer here to show the damage:

(https://imgur.com/YRup5fk.jpg)

More  :palm: :palm: :palm:

Replacement analogue board were generously provided for the meter by another forum member and it lives but my word what a shit show.
Title: Re: Handheld meter robustness testing
Post by: wolfy007 on September 10, 2020, 12:47:11 pm
Part II.  Enjoy.
https://www.youtube.com/watch?v=1YYvr_qe4Tw (https://www.youtube.com/watch?v=1YYvr_qe4Tw)

I think I have a parts unit 77 (had a nasty battery leak), I think I may have stolen the fuses and the fusable resistor, but it has a case and other bits in case you want to get it going and test in a proper case.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 10, 2020, 11:45:23 pm
I think I have a parts unit 77 (had a nasty battery leak), I think I may have stolen the fuses and the fusable resistor, but it has a case and other bits in case you want to get it going and test in a proper case.
Someone else (perhaps you) had extended a similar offer in the YT comments.   I appreciate the offer but I don't have any plans to revive it.  It's not a rare meter and not something I would have a need for.  If it were a 189, I would change my tune.   Then again, if it were a 189, it would have survived. 

The battery had leaked at one point with this meter as well.  It's odd to think of needing to split the case in order to gain access to the battery.  You can really tell this meter is old from some of their early design choices. 

They go on to develop the skills to later design and produce some very good products becoming a world leader to what we have today. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 10, 2020, 11:49:45 pm
Interesting. I haven't watched Part II yet. The rotary switch is trouble on these older meters IMHO. I had a 77 for years (which was my father's before) which wore out eventually and caused problems.

I wouldn't be at all surprised to learn that the mechanical switch has a high failure rate.  Thinking back to when they were used in TV set tuners and how it was a constant battle to keep them working (no remotes or digital tuning).   It seems like Fluke mastered how to make a switch reliable on the PCB.  Same is true for Brymen.  After that, things get pretty dicey from the ones I have looked at.   
Title: Re: Handheld meter robustness testing
Post by: wolfy007 on September 11, 2020, 12:59:50 am
I think I have a parts unit 77 (had a nasty battery leak), I think I may have stolen the fuses and the fusable resistor, but it has a case and other bits in case you want to get it going and test in a proper case.
Someone else (perhaps you) had extended a similar offer in the YT comments.   I appreciate the offer but I don't have any plans to revive it.  It's not a rare meter and not something I would have a need for.  If it were a 189, I would change my tune.   Then again, if it were a 189, it would have survived. 

The battery had leaked at one point with this meter as well.  It's odd to think of needing to split the case in order to gain access to the battery.  You can really tell this meter is old from some of their early design choices. 

They go on to develop the skills to later design and produce some very good products becoming a world leader to what we have today.

Honestly, looking at the 8060A, they almost went backwards with the 77, my guess is it was made to a price point. Though the 8060A doesnt have great input protection, its a great meter in most other respects, including having a battery/fuse access door...  ::)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 11, 2020, 01:30:10 am
I think I have a parts unit 77 (had a nasty battery leak), I think I may have stolen the fuses and the fusable resistor, but it has a case and other bits in case you want to get it going and test in a proper case.
Someone else (perhaps you) had extended a similar offer in the YT comments.   I appreciate the offer but I don't have any plans to revive it.  It's not a rare meter and not something I would have a need for.  If it were a 189, I would change my tune.   Then again, if it were a 189, it would have survived. 

The battery had leaked at one point with this meter as well.  It's odd to think of needing to split the case in order to gain access to the battery.  You can really tell this meter is old from some of their early design choices. 

They go on to develop the skills to later design and produce some very good products becoming a world leader to what we have today.

Honestly, looking at the 8060A, they almost went backwards with the 77, my guess is it was made to a price point. Though the 8060A doesnt have great input protection, its a great meter in most other respects, including having a battery/fuse access door...  ::)

I wrote Fluke off after my first one and vowed to never own another.  It really wasn't until I started running these tests and beat the crap out of that 101  that I gained some respect for them and decided to have another look.   Outside of the odd 87V failure that I still don't understand and this old 77,  all of Flukes DMMs have done very well against my tests.   Today, outside of the Brymen BM869s, the only DMM I use on a regular basis is the Fluke 189.   
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 12, 2020, 02:05:51 am
I think I have a parts unit 77 (had a nasty battery leak), I think I may have stolen the fuses and the fusable resistor, but it has a case and other bits in case you want to get it going and test in a proper case.
Someone else (perhaps you) had extended a similar offer in the YT comments.   I appreciate the offer but I don't have any plans to revive it.  It's not a rare meter and not something I would have a need for.  If it were a 189, I would change my tune.   Then again, if it were a 189, it would have survived. 

The battery had leaked at one point with this meter as well.  It's odd to think of needing to split the case in order to gain access to the battery.  You can really tell this meter is old from some of their early design choices. 

They go on to develop the skills to later design and produce some very good products becoming a world leader to what we have today.
Honestly, looking at the 8060A, they almost went backwards with the 77, my guess is it was made to a price point.

No, just different markets. The 8060A was a lab grade electronics meter, the 70 series was designed for the field and electrical use.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 22, 2020, 03:06:56 am
Talking about future videos and demonstrating Brymen's latest firmware for the BM869s. 

***
While making this video, I was very focused on the job which was changing that IC.   You don't want to damage the board or the IC.  As a result, I had forgot to press the record button when I was pulling the IC.   So, just imagine me there with my trusty heat gun....

https://www.youtube.com/watch?v=bDIx4ik0vvA (https://www.youtube.com/watch?v=bDIx4ik0vvA)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 22, 2020, 07:26:57 pm
I plan to look at the Brymen BM786 next.   Normally I like to show several meters when I run the tests to give viewers some idea how they compare with the non-destructive tests. 

Because the BM786 is a 60K counte meter and supports AC+DC,  I am leaning towards meters that support AC+DC and are a minimum of 40K counts.  I have a few meters that may be a good fit. 

*Brymen BM869s, 50K, $230,  repaired, no mods
*CEM DT9939, 40K,  $120,   repaired, no mods
*Fluke 189, 50K,  no longer offered,  virgin   
Gossen M248B, 200K,   $850,  modified with added shield
*Summit TPI194II, 50K, $240, repaired, no mods
UEI 121GW, 50K, $213, virgin 
*UNI-T UT181A, 60K,  $300, repaired and modified layout but shouldn't impact the performance. 
YOKAGOWA TY720, 50K, $500, repaired

I am thinking to rule out the Yokagowa and Gossen because of their high costs. 
With it being a non-destructive tests, the UEI would seem like a good fit except it continues to have so many unresolved problems.

I plan to run basically the same tests I have been, starting with non-destructive and working my way up. 

If there is anything you would like to see, outside of the normal, feel free to ask.   
Title: Re: Handheld meter robustness testing
Post by: EEVblog on October 22, 2020, 10:15:31 pm
UEI 121GW, 50K, $300, virgin 

FYI it's AU$300 or US$213
Title: Re: Handheld meter robustness testing
Post by: Gregg on October 22, 2020, 11:06:19 pm
Joe,
First I'd like to thank you for all of your efforts in testing multimeters in a no BS manner  :-+ :-+
Maybe you could include a Hioki DT4282 in your new round of tests.  I would lend you mine if you are only doing non-destructive tests.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 23, 2020, 01:57:08 am
UEI 121GW, 50K, $300, virgin 
FYI it's AU$300 or US$213
I have changed my post above to reflect the cost you have quoted.   I have also updated the spreadsheet.   

Joe,
First I'd like to thank you for all of your efforts in testing multimeters in a no BS manner  :-+ :-+
Maybe you could include a Hioki DT4282 in your new round of tests.  I would lend you mine if you are only doing non-destructive tests.

That's a very nice gesture.  Because I work with somewhat high voltages during these non-destructive tests,  I imagine we could still damage a meter with them.   While I use HIOKI products on a professional basis and would like to believe that your meter would have no trouble, there's no guarantee.   It's why I run these tests, to find out.

We have seen cases where meters have been damaged by what I would have considered just normal operation.   One of the tests I apply a full rectified 220V 60Hz to the meters and run them through there various modes.   5 meters were damaged from that one test.   That weak grill starter is another test I would have never thought would damage any meter, yet 7 were.   I will get much larger jolts from the door knobs and such during the dry winter.     

While I am grateful for the offer, I have to decline as there will always be some level of risk.  Obviously, I am not risk-averse but I don't expect others to be.   Maybe I will have a look at another HIOKI product down the road. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 23, 2020, 11:11:45 pm
Part 1

https://www.youtube.com/watch?v=pPCtnQa0Thc (https://www.youtube.com/watch?v=pPCtnQa0Thc)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 25, 2020, 07:04:05 pm
Part 2

https://www.youtube.com/watch?v=36NkAObcMec (https://www.youtube.com/watch?v=36NkAObcMec)
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 26, 2020, 12:42:36 am
As I said on the other thread: congratulations for the avant premiére version of the Brymen. This video series is off to a good start.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 26, 2020, 01:52:42 am
Really outside of the odd autorange problem, it seems fine so far.  What bothers me about it is that Dave has had at least one version of a prototype for some time and now has shown the final case.  So he's had plenty of time to find what ever problems the meter may have.   With his brand being on it, I am sure he's been doing a thorough job of it.    I came across the problem in the first 15 minutes of looking at it.   So I am a bit concerned that it could be unique to this one meter.   It's also very possible that I am screwing something up.    We just have to wait and see what Brymen says. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 26, 2020, 03:15:39 am
Well... Or you are really thorough with your tests, which may go under other people's radar screens. I do some tests on my channel but I did not assemble an HV setup like yours to validate the meters. It was always in my plans, but you know how life goes and how it affects hobbies... 😁
Title: Re: Handheld meter robustness testing
Post by: MiroS on October 26, 2020, 07:40:58 am
After two Part 1 and 2   not sure if that multimeter make any sense over e.g. BM867s.  I am starting to thing that it may be actually a kind of lower cost (for Brymen) variant.  I can see only one good thing so far - location of bargraph  is a way more optimal than in BM869s/BM867s. Do both use the same chips ?

Brymen should start to think less conservative way and add e.g. LED display to make this thing more attractive. 
Maybe at least the price will be really a long way below 150.



Title: Re: Handheld meter robustness testing
Post by: EEVblog on October 26, 2020, 08:27:13 am
After two Part 1 and 2   not sure if that multimeter make any sense over e.g. BM867s.

It's smaller, it costs less, bigger display, it has AutoHold, and it has an EF tester.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 26, 2020, 11:11:04 am
After two Part 1 and 2   not sure if that multimeter make any sense over e.g. BM867s.

It's smaller, it costs less, bigger display, it has AutoHold, and it has an EF tester.
I agree. The new meter seems to fit in a category that is more concerned about a general purpose use (lab/field) and does not care for dual display - something similar to choosing a BM857/9 versus a BM867/9. Besides, the 60000 counts can come in handy if you use 5V precision systems (the extra room above 5V can be of help).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 26, 2020, 12:15:25 pm
Talk about responsive, Brymen is working on it.  They suspect a problem with the new firmware.  Apparently earlier versions don't have the problem.  It sounds like they have a good handle on it.   I plan to hold off on further testing until they have it sorted out.     
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 26, 2020, 12:31:55 pm
Talk about responsive, Brymen is working on it.  They suspect a problem with the new firmware.  Apparently earlier versions don't have the problem.  It sounds like they have a good handle on it.   I plan to hold off on further testing until they have it sorted out.   
Funny how, in the past, that is what we would call it "beta testing": an almost finished product released to a few key customers to be trialed by fire. Nowadays this is almost the exception: alpha stage products released to the broad market where the issues are fed back to the devs through customer support. Oh well... Congratulations in reporting the bug.

Now, if others could get a clue and follow the same pattern of development cycle and customer support...

(BTW, your findings prompted me to resurrect an old project of mine for a HV low current Power Supply to test DMMs in more daring conditions - as well as exercise several HV capacitors).
Title: Re: Handheld meter robustness testing
Post by: MiroS on October 26, 2020, 01:26:01 pm
After two Part 1 and 2   not sure if that multimeter make any sense over e.g. BM867s.

It's smaller, it costs less, bigger display, it has AutoHold, and it has an EF tester.
I agree. The new meter seems to fit in a category that is more concerned about a general purpose use (lab/field) and does not care for dual display - something similar to choosing a BM857/9 versus a BM867/9. Besides, the 60000 counts can come in handy if you use 5V precision systems (the extra room above 5V can be of help).

Really I would not be sure , 857s price is 133EUR  also below 150 USD  ... that would maybe sense if that would cost below 100 or so.
857s seems to be far more universal one.
Title: Re: Handheld meter robustness testing
Post by: MiroS on October 26, 2020, 01:27:35 pm
Talk about responsive, Brymen is working on it.  They suspect a problem with the new firmware.  Apparently earlier versions don't have the problem.  It sounds like they have a good handle on it.   I plan to hold off on further testing until they have it sorted out.   

It looks that my rule 'stay away from fresh multimeter' may work again  :P
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 26, 2020, 02:10:17 pm
After two Part 1 and 2   not sure if that multimeter make any sense over e.g. BM867s.

It's smaller, it costs less, bigger display, it has AutoHold, and it has an EF tester.
I agree. The new meter seems to fit in a category that is more concerned about a general purpose use (lab/field) and does not care for dual display - something similar to choosing a BM857/9 versus a BM867/9. Besides, the 60000 counts can come in handy if you use 5V precision systems (the extra room above 5V can be of help).

Really I would not be sure , 857s price is 133EUR  also below 150 USD  ... that would maybe sense if that would cost below 100 or so.
857s seems to be far more universal one.
Exchange rates vary, but today 133 EUR = 157 USD, so there is no difference.
 
From the page I see at TME, the BM857 is 145 USD, which even still puts it in the same category of the other two (BM867 shows for me at 156 USD), making the difference too small to be considered another class.

The BM857 and the BM786 are quite similar with an edge for the BM786 if you don't need to do battery or trend measurements (the 500k counts mode)
Title: Re: Handheld meter robustness testing
Post by: MiroS on October 26, 2020, 03:17:06 pm
After two Part 1 and 2   not sure if that multimeter make any sense over e.g. BM867s.

It's smaller, it costs less, bigger display, it has AutoHold, and it has an EF tester.
I agree. The new meter seems to fit in a category that is more concerned about a general purpose use (lab/field) and does not care for dual display - something similar to choosing a BM857/9 versus a BM867/9. Besides, the 60000 counts can come in handy if you use 5V precision systems (the extra room above 5V can be of help).

Really I would not be sure , 857s price is 133EUR  also below 150 USD  ... that would maybe sense if that would cost below 100 or so.
857s seems to be far more universal one.
Exchange rates vary, but today 133 EUR = 157 USD, so there is no difference.
 
From the page I see at TME, the BM857 is 145 USD, which even still puts it in the same category of the other two (BM867 shows for me at 156 USD), making the difference too small to be considered another class.

The BM857 and the BM786 are quite similar with an edge for the BM786 if you don't need to do battery or trend measurements (the 500k counts mode)
Oh me ...  I meant not BM657, but BM867S ... sorry for the mess.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 27, 2020, 12:00:41 am
Talk about responsive, Brymen is working on it.  They suspect a problem with the new firmware.  Apparently earlier versions don't have the problem.  It sounds like they have a good handle on it.   I plan to hold off on further testing until they have it sorted out.   
Funny how, in the past, that is what we would call it "beta testing": an almost finished product released to a few key customers to be trialed by fire. Nowadays this is almost the exception: alpha stage products released to the broad market where the issues are fed back to the devs through customer support. Oh well... Congratulations in reporting the bug.

Now, if others could get a clue and follow the same pattern of development cycle and customer support...

(BTW, your findings prompted me to resurrect an old project of mine for a HV low current Power Supply to test DMMs in more daring conditions - as well as exercise several HV capacitors).

I'm looking forward to seeing what you come up with for your own test standards and equipment.    When you start working on it and running them, feel free to expand on this thread. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 28, 2020, 09:28:34 am
Sounds like Brymen may have a fix.  I'm surprised that they responded this quick, but it also sounded like they had a good idea where the problem was when I first wrote them.   

While I offered to change the microcontroller,  they have shipped a new meter.   I should have an update in a few days for you. 
Title: Re: Handheld meter robustness testing
Post by: EEVblog on October 28, 2020, 11:21:14 am
Sounds like Brymen may have a fix.  I'm surprised that they responded this quick, but it also sounded like they had a good idea where the problem was when I first wrote them.   
While I offered to change the microcontroller,  they have shipped a new meter.   I should have an update in a few days for you.

Sorry, haven't been following, is this the BM786?
If so what was the issue?
Title: Re: Handheld meter robustness testing
Post by: MiroS on October 28, 2020, 03:33:33 pm
Yes it is, minus EEVblog blue case (see reply #3770) An issue with AC+DC was found, so we get the benefit of Joe's testing.

I think testing is not finished yet,  Joe may find new one >:D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 29, 2020, 12:01:54 am
Yes it is, minus EEVblog blue case (see reply #3770) An issue with AC+DC was found, so we get the benefit of Joe's testing.

I think testing is not finished yet,  Joe may find new one >:D

It's possible.   With Brymen sending a whole new meter,  most likely I will run through all the basic checks off camera.   I doubt viewers will want to sit through that boring checkout a second time.   Assuming it works, I'll make mention of it and then show it running through all the problematic tests.  Most likely, I will then run the meter through a series of waveforms.   By the end of Part 3,  I want to viewers as well as myself, to be confident that this problem has been resolved.   

I just checked the tracking and it looks like it is due to arrive in just a few days, so it won't be long. 
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on October 29, 2020, 12:24:29 am
Will you still run the problem meter through the rest of the tests?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 29, 2020, 02:38:55 am
Will you still run the problem meter through the rest of the tests?

Knowing it has a problem, I am not sure what we would learn.  People are already confused stating it's an AC+DC problem and it has nothing to do with that mode.  Adding another meter to the mix would surely add to the confusion.

What I have thought about do is to pull them both apart and verify there is no difference beyond the new firmware.    The life cycle test requires several days to run.  Transient testing both meters would also take a fair amount of time.   

If you have some thoughts about it, feel free to chime in.  If for example you were really only interested in seeing both meters on the waveform test, I could maybe paint one of the meters blue or something to clearly show which one is which.   It wouldn't be any effort in this case to run the two in parallel.  But again, considering it has a problem and the whole point it to show it was corrected, I don't see what we gain.
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on October 29, 2020, 03:12:31 am
Mostly just curious, but also thinking it might be a chance to see one fail early while the other manages to run most of the gauntlet, similar to what happened with the 87v tests. Been too long since I watched those now so I can't remember if there were actual differences in the board or not. Maybe not fair as one already is known to have a problem even if it is just firmware issue. Guess I was really just wanting to see the maximum number of meters fail (that are not mine) and I'm just being greedy.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 29, 2020, 04:56:04 am
Mostly just curious, but also thinking it might be a chance to see one fail early while the other manages to run most of the gauntlet, similar to what happened with the 87v tests. Been too long since I watched those now so I can't remember if there were actual differences in the board or not. Maybe not fair as one already is known to have a problem even if it is just firmware issue. Guess I was really just wanting to see the maximum number of meters fail (that are not mine) and I'm just being greedy.

The 87V that failed was quite old but I don't think that had anything to do with it.  You may recall after running a brand new one and seeing how well it held up,  I carefully ran the old one a second time going through each stage trying to sort out why it failed.  In the end, I had no answer.  I repeated the test on that same meter and it held up really well.  It seems when I dug into it, even some stray contamination on the board didn't make a lot of sense. 

In the case of the 87V, we had a hardware failure.  Running a second new one did at least give me enough confidence to have a second look at the old one. 

Now we apparently have a firmware problem and no hardware damage.   I think we have looked at enough Brymen products to be fairly confident that they know how to design a switch that will last and a front end that can take a fair bit of abuse.   I highly suspect we are looking at some fairly boring tests moving forward.   Of course, I thought that when I started too. 

I do have a few old Harbor Freight meters if you just want to see some hardware damage.     
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 09, 2020, 08:01:07 pm
Is the auto-range problem fixed on the Brymen 786? Does the 789 suffer from the same problem or other problems?
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 09, 2020, 10:06:30 pm
Does the 789 suffer from the same problem or other problems?

It would be the exact same code base, so almost certainly. Brymen said they have fixed it.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 09, 2020, 11:05:51 pm
Is the auto-range problem fixed on the Brymen 786? Does the 789 suffer from the same problem or other problems?

Welcome to the forum.   

I'm not in any sort of rush and am giving Brymen time to sort it out.  Until then, I have no plans to proceed with further testing.   It sounds like they have told Dave it's all working now, so maybe we can get back into it soon.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 02:08:12 am
Is the auto-range problem fixed on the Brymen 786? Does the 789 suffer from the same problem or other problems?
I'm not in any sort of rush and am giving Brymen time to sort it out.  Until then, I have no plans to proceed with further testing.   It sounds like they have told Dave it's all working now, so maybe we can get back into it soon.

They said they fixed the issue you raised and sent you a new meter. Not sure about the other stuff they hinted at.
Expect maybe a few years and thousands of units in the field to get all the small issues ironed out, that's what the BM235 took.
Title: Re: Handheld meter robustness testing
Post by: bc888 on November 10, 2020, 02:36:56 am

Nope! My BM235 was perfect and I got an early model. In fact I'm still in love with it although Tektronix is my regular one I have on the dinning room buffet...to the wife's annoyance. I want one of these new Eevblog Brymens for a potential son in law's Christmas present. Some folks are just hard to buy for and I don't want to give up my bm235. 

Dave, please convey to Brymen that Christmas is near!!!! Joe, (on occasion and this is one) you rock buddy!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2020, 03:14:14 am
They said they fixed the issue you raised and sent you a new meter. Not sure about the other stuff they hinted at.
Expect maybe a few years and thousands of units in the field to get all the small issues ironed out, that's what the BM235 took.
No doubt they are busy.  I haven't heard anything from them in a while.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 03:19:08 am
Nope! My BM235 was perfect and I got an early model.

It's been through probably four firmware revisions since it was released fixing small things. The issue that Joe found on the new meter most people would never notice, and I've seen that on other meters on the market. There is actually an issue (confirmed non-fixable though, Brymen call it a design limitation) in the BM235 that to my knowledge no one has encountered yet. Also present in some other meters on the market.
There are just so many permutations of signals and ranges and functions possible it's likely you could eventually find an issue with any meter on the market. Like it took a decade before someone found you could brick a Fluke 87V with a GSM signal.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 03:20:50 am
Dave, please convey to Brymen that Christmas is near!!!!

They have promised mid Nov delivery. But they also promised August and then October...
Title: Re: Handheld meter robustness testing
Post by: Monkeh on November 10, 2020, 03:30:16 am
There is actually an issue (confirmed non-fixable though, Brymen call it a design limitation) in the BM235 that to my knowledge no one has encountered yet.

Do elaborate..

So far I've noticed the undocumented threshold for low-z, which threw me.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2020, 04:18:18 am
The issue that Joe found on the new meter most people would never notice, and I've seen that on other meters on the market. ...
I noticed it withing a few minutes.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 09:51:44 am
The issue that Joe found on the new meter most people would never notice, and I've seen that on other meters on the market. ...
I noticed it withing a few minutes.

Because you just so happened by chance to have a test and level etc that showed up that particular issue. It could have just as easily been at some other signal level or frequency or waveshape you didn't test for. As I said, the permutations are huge.
Title: Re: Handheld meter robustness testing
Post by: bd139 on November 10, 2020, 09:55:22 am
Just out of interest is someone developing (at Brymen) a test plan of all potential issues from previous meters and testing new products against them? This is vastly lacking in QA environments I've found even at large companies. New product? Same issues as the last generation! :(
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2020, 01:19:04 pm
Because you just so happened by chance to have a test and level etc that showed up that particular issue. It could have just as easily been at some other signal level or frequency or waveshape you didn't test for.

The plan is to run a more extensive library of waveforms but nothing I haven't shown before.   Brymen should have every possible opportunity to improve their design before I run it.   After all, I gave the EEVBLOG/UEI 121GW 2 years.     

Quote
As I said, the permutations are huge.

Infinite but I'm sure you are aware there are some standards that are commonly used in the industry.  I would imagine that many companies who design products for the AC mains, go so far as to have their own custom waveforms in their tool bags.     
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2020, 01:44:04 pm
One of the more interesting meters I looked at was the Fluke T6.  After aev, agv something reviewed one and slammed Fluke with lots of drama, several people asked me to have a look.  In this case the person making the review was clueless about how to use it because that half page was too much to read.  I picked up the same meter and AC adapter to repeat their tests before running my own.   The meter did a pretty decent job handling most of the waveforms.   

I did get some feedback (I assume from the electricians who the meter was designed for) about their lack of trust.   Seeing the meter fail in a few cases, I'm sure didn't help build that confidence but it certainly did much better than how it was being portrayed.   

https://www.youtube.com/watch?v=k8hhtTtWfVc&feature=youtu.be (https://www.youtube.com/watch?v=k8hhtTtWfVc&feature=youtu.be)
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 10, 2020, 04:11:10 pm
I would like to know what firmware changes and what bugs were fixed on the Brymen 786 apart from getting the nS function.

I'd be hesitating between Brymen 869 and 789/86.

The Brymen 7 series is newer and has more features, although it is less accurate.

I would use it for electronic repairs.
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 10, 2020, 07:24:39 pm
I would like to know what firmware changes and what bugs were fixed on the Brymen 786 apart from getting the nS function.

I'd be hesitating between Brymen 869 and 789/86.

If you need a meter today then get the 869. :-//

I would use it for electronic repairs.

a) A BM235 is enough meter for that and you can buy a decent soldering iron with the money you save.
b) You need at least two meters.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on November 10, 2020, 08:11:46 pm

b) You need at least twenty meters.

FTFY    :-DMM
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 10:43:09 pm
I would like to know what firmware changes and what bugs were fixed on the Brymen 786 apart from getting the nS function.

The code base will almost certainly be identical on models, there would just be flags in the software to enable features like nS.

Quote
The Brymen 7 series is newer and has more features, although it is less accurate.

It's actually more accurate than the 869 on DC current.
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 10, 2020, 11:18:37 pm
I would like to know what firmware changes and what bugs were fixed on the Brymen 786 apart from getting the nS function.

The code base will almost certainly be identical on models, there would just be flags in the software to enable features like nS.

Quote
The Brymen 7 series is newer and has more features, although it is less accurate.

It's actually more accurate than the 869 on DC current.


1/
It looks like the 150USD gone sky-high to 188USD and with tax  ... 184USD   :-/O ( 158.82 € excl. VAT )
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

2/
Available from 10.01.2021, other models are also presented, like BM785 Available from 24.12.2020 for  125.21 € excl. VAT ,  BM789  starting 24.12.2020 for  150.42 € excl. VAT
Eee, really rationaly  thinking will be to  skip BM786 and  go for less expensive and better  BM789 , avaiable  earlier

3/
Overal spec is not bad, but actually DC current accurancy is not that important, but AC indeed is quite important if specified for  wide frequency range.

Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 11:37:44 pm
1/
It looks like the 150USD gone sky-high to 188USD and with tax  ... 184USD   :-/O ( 158.82 € excl. VAT )
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

2/
Available from 10.01.2021, other models are also presented, like BM785 Available from 24.12.2020 for  125.21 € excl. VAT ,  BM789  starting 24.12.2020 for  150.42 € excl. VAT
Eee, really rationaly  thinking will be to  skip BM786 and  go for less expensive and better  BM789 , avaiable  earlier

If it's more than the 789 then that's pretty dumb pricing. I can sell it for well under US$150.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 10, 2020, 11:54:17 pm
1/
It looks like the 150USD gone sky-high to 188USD and with tax  ... 184USD   :-/O ( 158.82 € excl. VAT )
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

FYI I don't know where they got "paperwhite backlight" or that image from, but the backlight certainly doesn't look like that white or even.
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 11, 2020, 12:28:57 am
1/
It looks like the 150USD gone sky-high to 188USD and with tax  ... 184USD   :-/O ( 158.82 € excl. VAT )
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

FYI I don't know where they got "paperwhite backlight" or that image from, but the backlight certainly doesn't look like that white or even.

paper-white is in Brymen pdf file.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 11, 2020, 12:40:29 am
1/
It looks like the 150USD gone sky-high to 188USD and with tax  ... 184USD   :-/O ( 158.82 € excl. VAT )
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

FYI I don't know where they got "paperwhite backlight" or that image from, but the backlight certainly doesn't look like that white or even.

paper-white is in Brymen pdf file.

So it is. I hadn't seen the datasheet before. Well, don't expect "paper white".
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 14, 2020, 04:05:21 pm
Just a short update.

As Dave mentioned, Brymen sent me a second BM786.  I have continued to provide them with feedback which they take very seriously.  It's been a night and day difference working with Brymen compared to say Gossen (and other companies). 

I understand that solving problems takes time.  As responsive as they have been, I suspect Brymen's team of engineers have been working in overdrive to continued to improve their design prior to release.   We should have something ready in the next week or two.  I'm looking forward to showing it off to you.

Shown are the two 786 test meters  (note, the 181A is back on the charger). 
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 14, 2020, 09:01:34 pm
I have seen the 2 videos of the Brymen 786 tests, part 1 and part 2. Congratulations, great job. If brymen sent you a new meter with the problems solved, could you do a new test to see if the bugs in videos 1 and 2 are solved? Test only the faults. What worked well is not necessary. It would be a lot of work to do the same thing again.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 14, 2020, 09:31:10 pm
That's the plan Stan.
Title: Re: Handheld meter robustness testing
Post by: nightfire on November 14, 2020, 10:30:26 pm

1/
It looks like the 150USD gone sky-high to 188USD and with tax  ... 184USD   :-/O ( 158.82 € excl. VAT )
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

2/
Available from 10.01.2021, other models are also presented, like BM785 Available from 24.12.2020 for  125.21 € excl. VAT ,  BM789  starting 24.12.2020 for  150.42 € excl. VAT
Eee, really rationaly  thinking will be to  skip BM786 and  go for less expensive and better  BM789 , avaiable  earlier

3/
Overal spec is not bad, but actually DC current accurancy is not that important, but AC indeed is quite important if specified for  wide frequency range.

On the Welectron Shop site, now the 786EEV, 789 and 859s are offered for the same price: 158.82 excl. sales tax. (ok, 158.83 for the 859s, but thats close enough...)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 17, 2020, 10:31:04 pm
Just how good are Brymen's team of engineers?   You be the judge!

https://www.youtube.com/watch?v=Vgmf4mgDyHE (https://www.youtube.com/watch?v=Vgmf4mgDyHE)
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 17, 2020, 11:51:14 pm
Although it measures a bit below the BM879 and Uni-T 181, the new improvements make me like the BM786 more than the BM869 for my work. Great job as always Joe. Thank you so much.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 12:35:48 am
Although it measures a bit below the BM879 and Uni-T 181, the new improvements make me like the BM786 more than the BM869 for my work. Great job as always Joe. Thank you so much.

It's actually closer but some idiot had forgotten to turn off the VFD mode before starting the test.  Someone had post about the bargraph not working in that last test as well.  This is disabled when VFD is selected. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 18, 2020, 08:30:14 am
Interesting to see the Fluke 87V falling apart in tests where even a Uni-T keeps on going.   :P

And ... yet more confirmation that Brymen is the new king of multimeter manufacturers.
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 18, 2020, 10:25:57 am
And ... yet more confirmation that Brymen is the new king of multimeter manufacturers.

Fluke should bring back 189 to make market position harder to Brymen. That old 189 is still better than this new Brymen (neglecting the price)

Not checked manuall, they for sure described this, but I noticed that 60000 counts is not a full '60000'.
AC is cut to two digits after dot, the same for  resistance, same for current , that looks sometimes more like 6000 than 60000.
Actually e.g. 1mOhm resolution would be really very usefull.
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 18, 2020, 11:10:09 am
Not checked manuall, they for sure described this, but I noticed that 60000 counts is not a full '60000'.

That's the specification in the manual, yes, but in practice they do a lot better than that. Digital calibration means they're usually accurate down to the last digit or so.

(when they're at their calibration temperature...)
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 18, 2020, 11:36:07 am
And ... yet more confirmation that Brymen is the new king of multimeter manufacturers.

Fluke should bring back 189 to make market position harder to Brymen. That old 189 is still better than this new Brymen (neglecting the price)

Not checked manuall, they for sure described this, but I noticed that 60000 counts is not a full '60000'.
AC is cut to two digits after dot, the same for  resistance, same for current , that looks sometimes more like 6000 than 60000.
Actually e.g. 1mOhm resolution would be really very usefull.

F189 has multi display, logging, etc. It is better in features.

But can you explain what are you talking about 6000 digits?
Only time BM786 has 6000 digits is in Crest (high speed Min/max mode).

Also 1mOhm resolution is useless without 4w (Kelvin) measurements..

EDIT: what MiroS said, it seems that in some tests, BM786, when autoranging stayed in 600V AC mode, even when measuring 32 V. So that explains what MiroS said.
It definitely has 600mV, 6V and 60V AC range and it is full 60000 in all of them, but somehow it didn't autorange to those lower ranges, so 32, 35 and 40V was measured in 600V AC range.
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 18, 2020, 12:04:55 pm

But can you explain what are you talking about 6000 digits?


All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 12:07:55 pm
Interesting to see the Fluke 87V falling apart in tests where even a Uni-T keeps on going.   :P

Sorry, but I don't follow.  I showed the 87V with the new Brymen and Fluke 189.   I assume you are referring to the UT181A as it was the only UNI-T product I show in the video.   If you could explain your statement, I may be able to provide you with some insight.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 18, 2020, 12:28:04 pm

But can you explain what are you talking about 6000 digits?


All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.
Title: Re: Handheld meter robustness testing
Post by: HKJ on November 18, 2020, 12:31:55 pm
No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.

Was it the same ranges where there was a high AC voltage on the input?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 12:34:07 pm
Fluke should bring back 189 to make market position harder to Brymen. That old 189 is still better than this new Brymen (neglecting the price)

I am guessing the market for a high end basic meter like this is very small.  Similar to the 289.   I understand that there was some diagnostics software written specifically for the 189.   The company that wrote it bought a lot of these meters.   That's in the past.     

There are cases where the Brymen 786 will outperform the 189 but again, its not anything that would concern me.   Overall though, I agree the 189 is a better meter.  Looks like I can still find stock. About $550 if you wanted a brand new one.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on November 18, 2020, 07:15:09 pm

But can you explain what are you talking about 6000 digits?


All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.
S
MiroS, Sinisa, indeed this is a weird behaviour and to me a bug. Sure, while Joe had the waveform with plenty of DC offset, I imagine there was a chance the autorange could be confused in ranges, but not after wards, where a pure AC was applied.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 07:51:22 pm

But can you explain what are you talking about 6000 digits?


All is about resolution e.g. for AC this will be 39.95 , but not 39.954V, e.g. for resistance it will be 28.04, but not 28.041 Ohms, e.g. for current 50.02 but not 50.025mA so really not different to a 6000 count multimeter.
I would not cry for AC volts , but actually 1mOhm resistance would be really very usefull.The same for AC current (10A socket).

No it is not like that. It is 60000 counts, BUT, for some reasons, on some measurements it didn't autorange to 60V AC range for 32V measurement, but stayed on 600V range, so it reads 032.00 V.
S
MiroS, Sinisa, indeed this is a weird behaviour and to me a bug. Sure, while Joe had the waveform with plenty of DC offset, I imagine there was a chance the autorange could be confused in ranges, but not after wards, where a pure AC was applied.

Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 18, 2020, 08:58:51 pm
Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

I personally don't think it is a major problem, it measures correctly, shows correct value, it simply didn't show max resolution. But it is not dangerous, like showing 4V when there is 232V being measured. And if you are measuring and this shows, you know what the problem is and can manually range if needed. That last digit is not accurate on AC anyways ...
But sure, if it can be fixed, it will be "betterer".

As for comparison with other meters, on that topic I have the opinion that you should strive to be as good as you can, not legitimize mediocrity by being as bad as others ("if Fluke doesn't do better, we don't have to" mentality...).  It might be educational to see how some other meters cope with it, just because it is not hard to simply add them into frame once you take effort to create setup.

Regards,

Sinisa
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 18, 2020, 09:16:17 pm
Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

...

There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on November 18, 2020, 09:21:54 pm
Seems a follow up video for clarification might be worth it just for the sake of viewers that might not read the discussion here or dig thru the comments on the video.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 09:53:50 pm
I'll repeat it using the same waveforms, but add a few more.  I will also run the same two voltage levels, but will also run it above 350.   I will run the video slower and will use the Fluke 189 and Brymen BM869s as a comparison.   I will leave the DSO out of it and overlay the labview application as before.   



There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.

I responded to it but unless they provide details of what they were doing, I have no idea what they are going on about.  It's like the person here who claimed to have bought five Brymen meters that all failed the same way.   There's a point where you just can't help these people.   But because you have asked, what I will do is add a second BM869s.  I will wrap the leads around the HV lines feeding the meters and attach a 560Kohm resistor to it. 


... Definitely check whether it is VFD related.
...
But sure, if it can be fixed, it will be "betterer".

To me a standard waveform would be something like IEC413. 

There's nothing to fix.  Again it's documented in the manual. Yes, it is all to do with the VFD mode.   No big deal though to show it.  Give me a while to repeat it. 
Title: Re: Handheld meter robustness testing
Post by: dcac on November 18, 2020, 10:44:45 pm
Interestingly the BM786 LCD does seem to have a High Voltage warning symbol - but it's not mentioned in the manual and does never seem to be displayed either. Any particular reason for that? I think it's the same on BM869.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1114054)
Title: Re: Handheld meter robustness testing
Post by: dcac on November 18, 2020, 11:03:32 pm
The BM786 Bar-graph does seems to have a strange behavior. Here it seems to be in 600.00V DC range but bar-graph would then correspond to 200 volts or so. Also note the DC is low but the BM786 seems to stay in the 600V DC as long as the overlayed AC is preset - it does not shift the range down to DC 5.0000V like the left Fluke 189.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1114058)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 11:07:59 pm
Could be a common display for them.  If you look at the manuals cover page, there are other symbols besides that one that they have removed.   T1-T2 would be nice to have.  I use that fairly frequently with the BM869s.  It's actually one of the reasons I bought my first Brymen! 

I ran the test...  This may be the easiest video to edit that I have ever made.   Won't be long.  If you would like it running at normal speed (uncompressed)  let me know.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 18, 2020, 11:09:52 pm
The BM786 Bar-graph does seems to have a strange behavior. Here it seems to be in 600.00V DC range but bar-graph would then correspond to 200 volts or so. Also note the DC is low but the BM786 seems to stay in the 600V DC as long as the overlayed AC is preset - it does not shift the range down to DC 5.0000V like the left Fluke 189.


Are you aware that the bargraphs auto range?  Full scale of 5 could mean 500V 50V 5V 500mV....

Now I see what you are getting at.  Yes, that bargraph would seem to be showing 200V.  I wonder if in these cases if the bargraphs range differs from the readout's.   

Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 18, 2020, 11:17:20 pm
To me a standard waveform would be something like IEC413. 

There's nothing to fix.  Again it's documented in the manual. Yes, it is all to do with the VFD mode.   No big deal though to show it.  Give me a while to repeat it.

Thank you for pointing this out. I went and read manual.. In VFD mode there is only 600 and 1000V range.
That does explain it..
As I said, I have no problem with that, VFD and LoZ are specialist modes.
I think meter is excellent as is.. I was slightly sarcastic, that's why I used word "betterer"...
Take care,
Sinisa
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 19, 2020, 01:14:00 am
AC Line test with the VFD turned off. 

https://www.youtube.com/watch?v=7XyZTJkI3Qk (https://www.youtube.com/watch?v=7XyZTJkI3Qk)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 19, 2020, 02:02:50 am
I have repeated the DCV test to see if I could replicate the problem with the bargraph.  It doesn't look like it locks up but rather that they calculate it differently than the readout.  It's really strange but easy to reproduce.  I have asked Brymen if they can fill us in on what it's doing.   
Title: Re: Handheld meter robustness testing
Post by: dcac on November 19, 2020, 12:27:43 pm
Interestingly the BM786 LCD does seem to have a High Voltage warning symbol - but it's not mentioned in the manual and does never seem to be displayed either. Any particular reason for that? I think it's the same on BM869.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1114054)

Well, I was wrong about the BM869 - its LCD does not seem to have the High or rather ‘Hazardous’ voltage warning symbol.

That warning symbol probably isn’t a requirement by any safety standard. And I’m not suggesting Brymen is less safe or anything like that - I just noticed the BM786 LCD has a symbol for it - so perhaps Brymen has planes to implement it in the future.

Title: Re: Handheld meter robustness testing
Post by: Cliff Matthews on November 19, 2020, 01:18:57 pm
Good point. It would seem Brymen is listening, so maybe the BM786 will use it in the final release.
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 19, 2020, 03:00:55 pm
In online stores they say that it will be available on 10.01.2021. If they are fixing the problems now, will a final version be in stores by that date?
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 19, 2020, 03:53:45 pm
That warning symbol probably isn’t a requirement by any safety standard. And I’m not suggesting Brymen is less safe or anything like that - I just noticed the BM786 LCD has a symbol for it - so perhaps Brymen has planes to implement it in the future.

Occam's razor says it's just a generic LCD.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on November 19, 2020, 06:54:38 pm
Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

...

There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.

I can confirm that this is a thing. It starts at around 520k and persists up to 660k or so. It can be exacerbated by holding the meter in your hands.

I ran cables from a resistance decade to my meter, with a few cm being parallel to my PC power lead.

I was unable to duplicate the effect with my 87V, 289, or UT139C.

I'm guessing it's some kind of low hysteresis between the autorange selection between 600k and 6M, as it basically starts flipping between them at a rate of two or three Hz.
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 19, 2020, 08:45:57 pm
It can be exacerbated by holding the meter in your hands.

.. or by rotating multimeter with your body like 90 degrees left or right holding the meter in hand.
That looks like accelerometer/divergence sensor :-DD
That may be static charge effect (?). Nothing like that on FK289 , or F87V. 

It seems to be a real problem, handheld multimeter by design is 'moving/rotating' .
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 19, 2020, 10:41:48 pm
https://youtu.be/_SD24ujP3vg
I found this on YT
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 19, 2020, 10:47:45 pm
Again, during the last test where the DC had been removed, the meter was set to VFD.  The bargraph will be disabled, the filter will be active causing a bit of an voltage difference for the higher frequency content waveforms and yes, it only displays two places past the decimal point.  We can see this on page 24. 

Is it worth repeating this test with the VFD disabled?   I could also just run two meter and remove the DSO, maybe slow it down a bit further to make it easier to track.   We could also increase the number of waveforms.  This test requires little effort to setup so if you feel it's worth it, let me know. 

I am still not sure what the comment was about UNI-T not having a problem.  I could toss the 87V into the mix as well if this is what you want to see.  It just gets more difficult for me anyway, to follow what is going on with so many devices active at once.

Hi Joe,

If it is not big effort and you're willing to do it, sure, it would be nice.
It would be nice to see limits of this, and maybe with what waveforms it will happen. I doubt autoranging will have problem with standard waveforms...
Maybe see it through full range (6V, 60V, 600V) ... Definitely check whether it is VFD related.

...

There was a comment on YT that BM869s has a problem with 560kOhm resistance measurement if it is performed close to power cord.  I would propose to add this to the list of tests if you will decide to make next tests with BM786.

I can confirm that this is a thing. It starts at around 520k and persists up to 660k or so. It can be exacerbated by holding the meter in your hands.

I ran cables from a resistance decade to my meter, with a few cm being parallel to my PC power lead.

I was unable to duplicate the effect with my 87V, 289, or UT139C.

I'm guessing it's some kind of low hysteresis between the autorange selection between 600k and 6M, as it basically starts flipping between them at a rate of two or three Hz.


Yep, confirmed. I didn't even need mains to do it. At one point I could just stand there holding the cables.
I goofed the Mohm range test, should have been 5.6M, but I tried that and it's fine, so definitely only 560k.
I'll start a new thread for this issue.
https://www.youtube.com/watch?v=EJ6KCpHc--4 (https://www.youtube.com/watch?v=EJ6KCpHc--4)
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 19, 2020, 10:51:25 pm
Please post about he BM869 issue here so we don't pollute this thread.
https://www.eevblog.com/forum/testgear/brymen-bm869-resistance-quirk/ (https://www.eevblog.com/forum/testgear/brymen-bm869-resistance-quirk/)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 19, 2020, 10:55:12 pm
I also tried the resistance test on a few ranges and with the old and new firmware.  It seems to be this one range.  Hysteresis and switch points are similar to my Fluke 189.   I tried a few other Brymen products.  It seems to be related to the 869s.  The YT comment suggested all Brymen products suffer from this problem.  What other products exhibit this problem?  I assume the people who are posting here have contacted Brymen already.  What was their response?
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on November 19, 2020, 11:21:14 pm
Just to clarify, Dave's is the 869 non S model. The video linked by MiroS shows the same issue on the 869s
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 20, 2020, 10:23:55 am
The video linked by MiroS shows the same issue on the 869s

Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.
From Dave message - resisatnce sims to work, but who knows which firmware is in Dave multimeter, that may be old one, Joe could be one of first external testers for corrected/imporved  firmware.

I think Brymen may be still not aware of issues, I do not think that anyone reported this to them for 869s.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 20, 2020, 10:45:44 am
The video linked by MiroS shows the same issue on the 869s

Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.
From Dave message - resisatnce sims to work, but who knows which firmware is in Dave multimeter, that may be old one, Joe could be one of first external testers for corrected/imporved  firmware.

I think Brymen may be still not aware of issues, I do not think that anyone reported this to them for 869s.

1. First problem is one with resistor. It has to do with instrument having high impedance and on the edge of autoranging ... It does seem a bit nervous, but any meter can be destabilised this way if you try hard enough. This is something I would like if Brymen could make better, but would not change the meter because of it.
2. Second problem I don't really understand what is he doing..
3. 3rd problem is not a problem at all and has nothing to to with VFD,  Crest mode has less resolution, in order to be fast enough. It's in a manual.
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 20, 2020, 11:18:18 am
Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.

It would be nice to try the new meter. I agree. Has it been tested with Fluke cables?
Title: Re: Handheld meter robustness testing
Post by: Chalton_trc on November 20, 2020, 11:20:42 am
I don't know if Joe will have information from Brymen ... In Welectron they say that the BM786 will be available on 10.01.2021. If they are fixing the issues now, will there be a final version in stores by then? Does anyone know anything about this?
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 20, 2020, 11:54:15 am
Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.

It would be nice to try the new meter. I agree. Has it been tested with Fluke cables?


That is not my quote, sorry..

WTF it has to do with the cables? Brymen cables are better quality than some Fluke cables, and none of them are shielded. They will all pick up same electric/magnetic field.
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 20, 2020, 12:10:37 pm
Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.

It would be nice to try the new meter. I agree. Has it been tested with Fluke cables?

What's wrong with Brymen cables? I've got some and they're awesome.
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 20, 2020, 12:12:01 pm
1. First problem is one with resistor. It has to do with instrument having high impedance and on the edge of autoranging ... It does seem a bit nervous, but any meter can be destabilised this way if you try hard enough.

Yep. I bet it will disappear if you switch to manual ranging.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 20, 2020, 12:30:03 pm
1. First problem is one with resistor. It has to do with instrument having high impedance and on the edge of autoranging ... It does seem a bit nervous, but any meter can be destabilised this way if you try hard enough.

Yep. I bet it will disappear if you switch to manual ranging.

Of course it will, it is autoranging problem. You have value right at the  edge of range, very high impedance on input and you're injecting maybe a volt of interference. That combined with fast frontend, makes a jittery autoranging.
We are all annoyed when things are not perfect, but it is not a real problem.


Also Dave's test with BM786 is invalid .. Of course that 60000 count meter won't have problem with 560 kOhm. It might have problem with 650 kOhm, because that is where it will have switchover and similarily high impedance.....

Later, I will try this with some meters, right on their switchover point, and high resistance mode.. I think many of those will have same problem, unless they have very slow autoranging, and very slow front end and sampling...
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 20, 2020, 12:37:46 pm
Also Dave's test with BM786 is invalid .. Of course that 60000 count meter won't have problem with 560 kOhm. It might have problem with 650 kOhm, because that is where it will have switchover and similarily high impedance.....

LOL! Yeah, good point.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 20, 2020, 01:15:57 pm
The video linked by MiroS shows the same issue on the 869s

Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.
From Dave message - resisatnce sims to work, but who knows which firmware is in Dave multimeter, that may be old one, Joe could be one of first external testers for corrected/imporved  firmware.

I think Brymen may be still not aware of issues, I do not think that anyone reported this to them for 869s.

I did try the latest updates with the 786 (at its switch point) and saw no problems.  I also looked at a few other Brymen products as it was mentioned "There is a noise problem with brymen multimeters." which I read as ALL Brymen multimeters.  The only one I saw a problem with were the two 869s I have (two versions of firmware).   I had gone so far as to twist the test lead around a long line cord to my lamp.  Even then it's the only meter I saw a problem with.  Really odd as it seemed to be the only range effected.  The Fluke 189 has close to the same switch points, hysteresis, test currents as the 869s and even with the twisted wires, I saw no effect.   No doubt I could inject enough noise to screw them up. 

The OP has not responded on if they contacted Brymen or not.  I find it odd that anyone would post about it in social media but not contact the company who designs it.  I've found them to be very responsive but they can't address what they are not aware of.   Depending how far back it goes, it could have been possibly rolled into the version that extended back light.   I'll write them next week if no one else responds.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 20, 2020, 01:29:26 pm
1. First problem is one with resistor. It has to do with instrument having high impedance and on the edge of autoranging ... It does seem a bit nervous, but any meter can be destabilised this way if you try hard enough.

Yep. I bet it will disappear if you switch to manual ranging.

Of course it will, it is autoranging problem. You have value right at the  edge of range, very high impedance on input and you're injecting maybe a volt of interference. That combined with fast frontend, makes a jittery autoranging.  We are all annoyed when things are not perfect, but it is not a real problem.

It does seem like we should have a standard way to test it.   Maybe inject a signal (transformer couple in series with the test resistor)  and find out where the 869s exhibits the problem, then add a 50% margin to that?   Get the coupling and lead length out of the picture.   Always test on the highest range switch point? 

I didn't check the UNI-T 181A but that may be another one to look at.  Someone could also try it with their 121GW with the latest firmware.   Maybe that super fast HIOKI? 
Title: Re: Handheld meter robustness testing
Post by: dcac on November 20, 2020, 02:27:03 pm
The video linked by MiroS shows the same issue on the 869s

Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.
From Dave message - resisatnce sims to work, but who knows which firmware is in Dave multimeter, that may be old one, Joe could be one of first external testers for corrected/imporved  firmware.

I think Brymen may be still not aware of issues, I do not think that anyone reported this to them for 869s.

1. First problem is one with resistor. It has to do with instrument having high impedance and on the edge of autoranging ... It does seem a bit nervous, but any meter can be destabilised this way if you try hard enough. This is something I would like if Brymen could make better, but would not change the meter because of it.
2. Second problem I don't really understand what is he doing..
3. 3rd problem is not a problem at all and has nothing to to with VFD,  Crest mode has less resolution, in order to be fast enough. It's in a manual.

My guess on the second “problem” -  he’s confused why the frequency reading shows zero Hz when he manually select higher ranges.

I don’t think it’s mentioned in the BM896 manual but minimum (RMS) AC volts required for the frequency readout at 50Hz seems to be:

Range:
500.00mV = 65mV
5.0000V    = 0.28V
50.000V    = 2.8V
500.00V    = 28V 
1000.0V    = 280V

So he’s first measuring 12.2V AC which is high enough for the 50.000V range, but not for the 500.00V or 1000.0V ranges.

Then he measures 116V AC which is high enough for the 500.00V range, but not for the 1000.0V range.


And just for comparison with the 121GW minimum (RMS) AC volts required for the frequency readout at 50Hz seems to be:

Range:
500.00mV = 15mV
5.0000V   = 0.15V
50.000V   = 1.5V
500.00V   = 15V 
600.0V     = 15V


So to an inexperienced user the BM896 might (possible) seem to be broken when it is in fact just different - or in this case less sensitive on the frequency display - than another multimeter.

Title: Re: Handheld meter robustness testing
Post by: MiroS on November 20, 2020, 06:42:24 pm

So to an inexperienced user the BM896 might (possible) seem to be broken when it is in fact just different - or in this case less sensitive on the frequency display - than another multimeter.

No , no ... look starting at 4:04 - 117AC on input ...

The same BUG with 235V AC 50Hz, no question for me , that is a real bug, easy to reproduce. I think that one is also unknown to Brymen and worth of testing with new Brymen multimeter.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 20, 2020, 07:29:44 pm

So to an inexperienced user the BM896 might (possible) seem to be broken when it is in fact just different - or in this case less sensitive on the frequency display - than another multimeter.

No , no ... look starting at 4:04 - 117AC on input ...

The same BUG with 235V AC 50Hz, no question for me , that is a real bug.

So he’s first measuring 12.2V AC which is high enough for the 50.000V range, but not for the 500.00V or 1000.0V ranges.

Then he measures 116V AC which is high enough for the 500.00V range, but not for the 1000.0V range.

And guess what, 235 V is still less than 280V needed to measure frequency in 1000V range..

So NOT a bug. Bug is unexpected behaviour. This is not unexpected behaviour. It is clearly documented in specifications. Fact is BM869S has frequency measurement that is not very sensitive, and you need to be in right range for it to work. It probably makes measurements stable and resilient to noise.
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 20, 2020, 08:03:38 pm

So NOT a bug. Bug is unexpected behaviour. This is not unexpected behaviour. It is clearly documented in specifications. Fact is BM869S has frequency measurement that is not very sensitive, and you need to be in right range for it to work. It probably makes measurements stable and resilient to noise.

Right , I am idiot  ->  '1000.0V    = 280V', but really ... |O

Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 20, 2020, 10:10:04 pm

So NOT a bug. Bug is unexpected behaviour. This is not unexpected behaviour. It is clearly documented in specifications. Fact is BM869S has frequency measurement that is not very sensitive, and you need to be in right range for it to work. It probably makes measurements stable and resilient to noise.

Right , I am idiot  ->  '1000.0V    = 280V', but really ... |O

I don't know you so I will have to trust your word on that.

I will repeat: I took my BM869S, connected it to 237.00 V 50Hz mains, it autoranged to 500V range and shown 50Hz correctly. Then I manually ranged to 1000V range, it shown 0237.0 V and 0 Hz. It didn't measure frequency , because according to datasheet, you need 500 V RMS minimum in 1kV range for frequency measurement to work. Is it inconvenient that it doesn't measure it in that range ? It probably might have been made to work, but who cares. Just leave it in autorange, it will autorange to 500V range and measure frequency nicely
Title: Re: Handheld meter robustness testing
Post by: EEVblog on November 20, 2020, 10:18:24 pm
The video linked by MiroS shows the same issue on the 869s
Actually this video is mentioning three problems for 869s, I think it is worth of checking is new multimeter is affected by them.
From Dave message - resisatnce sims to work, but who knows which firmware is in Dave multimeter, that may be old one, Joe could be one of first external testers for corrected/imporved  firmware.
I think Brymen may be still not aware of issues, I do not think that anyone reported this to them for 869s.

I have reported it to Brymen and sent a link to my video.
Seem like everyone is confirming it on their 869 and 869S.
No issue on the BM786 which switches at 650k, it's smooth as silk.
Best to keep this in the dedicated thread for this issue.
Title: Re: Handheld meter robustness testing
Post by: dcac on November 20, 2020, 11:12:29 pm

So NOT a bug. Bug is unexpected behaviour. This is not unexpected behaviour. It is clearly documented in specifications. Fact is BM869S has frequency measurement that is not very sensitive, and you need to be in right range for it to work. It probably makes measurements stable and resilient to noise.

Right , I am idiot  ->  '1000.0V    = 280V', but really ... |O

I don't know you so I will have to trust your word on that.

I will repeat: I took my BM869S, connected it to 237.00 V 50Hz mains, it autoranged to 500V range and shown 50Hz correctly. Then I manually ranged to 1000V range, it shown 0237.0 V and 0 Hz. It didn't measure frequency , because according to datasheet, you need 500 V RMS minimum in 1kV range for frequency measurement to work. Is it inconvenient that it doesn't measure it in that range ? It probably might have been made to work, but who cares. Just leave it in autorange, it will autorange to 500V range and measure frequency nicely

Just to clarify - In my previous post the "280V" was more a derived number as my boosted signal gen maxed out at 50V and then I tested with 230V mains and that wasn't enough either in the 1000.0V range. But now I tested with a better booster and my BM869s needs 265V RMS at 50Hz to register the frequency. But higher frequencies will likely require higher voltages.
   
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 20, 2020, 11:49:30 pm
I don't know you so I will have to trust your word on that.

oh do not take this literarly :)  50% of range seems to be really wired , especialy if you will look at lower ranges tresholds ... anyway it is what it is. I can not even imagine what real situation can require that so high. Anyway I made false statement, I can not blame Brymen for a bug, only for 'a feature'. I will tell that kind of differences are giving a shadow  on quite good multimeter. They should display OL or something like '------'  but not 0.000 Hz and than that is truly a bug to my eyes.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on November 20, 2020, 11:58:50 pm
Dave is right, we should be discussing this in a topic he created for that...
Title: Re: Handheld meter robustness testing
Post by: dcac on November 21, 2020, 12:08:53 am
I'm not sure if Dave meant that for all BM869 discussion or just for the 'resistance quirk'...

Please post about he BM869 issue here so we don't pollute this thread.
https://www.eevblog.com/forum/testgear/brymen-bm869-resistance-quirk/ (https://www.eevblog.com/forum/testgear/brymen-bm869-resistance-quirk/)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 21, 2020, 01:41:55 am
Quote
But higher frequencies will likely require higher voltages.
True. 

IMO, it all has to do with meter robustness so no big deal to put it here or where ever. 

Good to hear it's been reported. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 21, 2020, 05:47:03 pm
How sensitive is the BM869s in its upper resistance range compared with other meters?

Started by using the resistive decade box to determine the thresholds for the upper range.  Use the center as the test resistance.   Using my terminated  HP34401A signal generator and placing it in series with the DMM and the decade box.  Using a 50Hz  sinewave, increase the voltage until the DMM is unstable.  Reduce the voltage until it recovers. 

The newer Brymen BM869s with the latest firmware has thresholds of 540K and 470K ohms.  Setting the decade box to 505K, the meter is unstable at as low as 27mVRMS.  Test current was around 0.85uA.

The Fluke 189 that my friend gave to me, has thresholds of   560K and 470K oms.   Using a test resistance of 515Kohms, the meter was unstable as low as 740mVRMS.   Test currents are around 1uA

My UNI-T UT181A after being damaged, repaired and modified has thresholds of 600K and 550K.  Using 575Kohms, the meter was unstable as low as 680mVRMS.  It has an odd behavior where the longer it sits with the AC wave applied, the chances are it will have a problem.  For example, I can apply 1V and the meter will read the correct value for a short time, then bounce between ranges.   

The Yokogawa TY720, again damaged and repaired but no mods to meter.   Thresholds were 560K & 490K.  Testing at 535Kohms, I could test up to 3.52 Volts RMS and the readings were stable.  It of course effects the reading but it never hunts.   

The Brymen BM786 with the last firmware I received has thresholds at 660K and 600K.  Using a test resistance of 630K, the was unstable as low as 380mVRMS. 

How good is good enough?
The longest standard leads I have came from Keysight.  They are 1.4 meters long.   If I attach these to the decade box and run them aside a 120V 60 lamp cord for a few feet,  I get about 20mV.    It I use their entire length, about 30mV.    If I twist them the full length with the line cord, 10 turns total, about 43mV.     I'm not suggesting I would use a meter this way but it puts some numbers on the board.   

*****************
I was curious about the Gossen Ultra or what ever Gossen's marketing now calls it (PN# M248B).   Never damaged but a lot of Netic and copper foil added for shielding.  This meter has some pretty major problems but can throw up some very impressive data after I added all that shielding to it.     

I tried two tests with it.  First threshold was 310K and 270K.  The next was 3.1Meg and 2.7Meg.   I ran it at 290K and 2.9Meg.    In both cases, I could go to 7.1VRMS and saw no effect.   It's stable down to the last digit!  That's 290.771Kohms BTW.    I doubt the shielding I added helped at all with this testing other than I can get near the meter without it going unstable. 

Clip of the Gossen with up to 35V superimposed. 


The thresholds are correct but the data was not!   Repeating the test with the proper connections, at 270K the range was still stable up to 3.5VACRMS.  At 2.7M with 3.5V applied, again the range was stable but the values are off by a fair amount and the reading vary by about 40Kohms.  .

*****************
So for fun, using the prototype 121GW which was damaged, repaired, modified, aligned using hand picked parts.  Version 1.57 firmware.  Thresholds are 550K and 383K.  Using a test resistance of 467Kohms, the meters range is mostly stable up to 1VRMS.  The displayed resistance varies a lot.   Even with 18mV applied, the reading is not very stable.     

I tried it with the Production #1  121GW FW 2.02 as well and it seems about the same. 

When I first ran this test, I realized I had connected it up wrong when I ran the Gossen.  No wonder it was so stable!!  Should have rechecked the obvious.  Corrected above. 


Title: Re: Handheld meter robustness testing
Post by: MiroS on November 21, 2020, 06:27:16 pm
How sensitive is the BM869s in its upper resistance range compared with other meters?

Old Fluke 25/27  can  measure 2kOhms with 1V AC, 1MOhm with up to 2V AC noise.
That noise is visible as an oscillating  bar graph.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 21, 2020, 07:04:51 pm
How sensitive is the BM869s in its upper resistance range compared with other meters?

Old Fluke 25/27  can  measure 2kOhms with 1V AC, 1MOhm with up to 2V AC noise.
That noise is visible as an oscillating  bar graph.

Of course, randomly picking some points isn't going to tell us much.  If for example, I choose to test at 260Kohms with the BM869s (mid wayish point of the two ranges to allow for the highest immunity).  Remove the terminator from the 34401A and transformer couple it into the series chain.   I can now apply 36VRMS and the meter is still stable.   That's all fine but it's not helpful to this discussion.     

If you have some pots, you could try to find the thresholds, then measure the pots values.  Then set the pot to the mid point and try to see what voltage level upsets it. 

****
Just for fun, changed the decade box to 2Meg, similar to what I show in the video. Same 50Hz, 36VRMS being applied.  The BM869s is stable.  Explains why it was stable during my tests with a 1.9M part.      Again, same wrong setup as I mentioned with the Gossen.  The meter will begin to hunt at 750mV.  Still a huge improvement.  Makes more sense now..   :palm:
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 21, 2020, 09:05:09 pm

If you have some pots, you could try to find the thresholds, then measure the pots values.  Then set the pot to the mid point and try to see what voltage level upsets it. 


I took this data from Fluke manual, not by testing, no idea why Fluke published this for  2k and 1M, and no idea if this could be a trend that lower resistance is more sensitive (1V) than higher resistance (2V)
Title: Re: Handheld meter robustness testing
Post by: dcac on November 21, 2020, 10:24:17 pm
The newer Brymen BM869s with the latest firmware has thresholds of 540K and 470K ohms.  Setting the decade box to 505K, the meter is unstable at as low as 27mVRMS.  Test current was around 0.85uA.

That correspond very well with what I'm experience when measuring 10 x 100K SMD resistors in series on a small PCB. Using the Brymen test leads and holding one probe in each hand, no mains wire or power supplies are close by.

Everything is fine until 500K (5 x 100K) and my BM896s starts hunting. Then switching it to AC mV and repeat with the probes in same position I get 28mV RMS. I noticed by just changing the angle on the probes slightly I could get the voltage down to 22-24mV and this also caused the hunting to stop in Resistance mode.

   
Title: Re: Handheld meter robustness testing
Post by: MiroS on November 22, 2020, 03:48:48 pm

If you have some pots, you could try to find the thresholds, then measure the pots values.  Then set the pot to the mid point and try to see what voltage level upsets it. 


I took this data from Fluke manual, not by testing, no idea why Fluke published this for  2k and 1M, and no idea if this could be a trend that lower resistance is more sensitive (1V) than higher resistance (2V)


I have  compared for my curiosity BM869s, FK87V and FK289  - 2kOhm with 0.3V AC 50Hz:

BM869s - not able to show resistance at all
FK87V - no any problem at all, shows what is should , even in HiRes mode, nicely singaling noise on bargraph
FK289 - no any problem at all, shows what is should  and singaling noise on bargraph

FK28II - the same as FK87V
Title: Re: Handheld meter robustness testing
Post by: dcac on November 22, 2020, 04:09:17 pm
Here's two more for reference. I used one of those cheap KKmoon signal gens as you can easily run them from a 5V power bank and much exclude any mains interference. I verified I got the same results that BM869s starts hunting at about 28mV RMS - I also tested at 60Hz and here it was perhaps slightly more sensitive at 26mV RMS.

Then tested the 121GW - thresholds seems to be at 400K and 550K so tested at 470K and it could take 0.81V RMS before starting to hunt.

And then Agilent U1252A which seems to have thresholds at 450K and 510K so tested at 480K and it could take more than 2.0V RMS - of course the resistance value got noticeably distorted with even higher voltage - but it still would not hunt.

Edit: just noticed Joe already did the 121GW - but mine had FW 2.04 - I don't think that would make any difference though.

 
Title: Re: Handheld meter robustness testing
Post by: dcac on November 23, 2020, 11:47:32 am
I tried some measurements with my Picoscope + laptop on batteries, trying to minimize mains coupled interference as much as possible.

So this is BM869 measuring 525K resistance with a 10X 10M scope probe in parallel.

Two captures at 200mS and 500mS/div.

Cyan trace = 500K range.
Magenta trace = 5M range.
Blue trace = Hunting auto range.

You can see the faint overlayed 50Hz hum on all traces and then there’s about 10% overshoot each time the 500K range is selected. But as I do not have the schematics it’s difficult to speculate exactly what’s causing it. 

And then the overall hunting ‘frequency’ at about 6-7 SPS - doesn’t really make sense as BM869's nominal update rate is 5 SPS. So it actually seems to be hunting faster than that and that doesn’t seem to leave much time to settle after each range change.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 30, 2020, 02:13:13 pm
Quote
Quote from: joeqsmith on November 19, 2020, 02:02:50 am

    I have repeated the DCV test to see if I could replicate the problem with the bargraph.  It doesn't look like it locks up but rather that they calculate it differently than the readout.  It's really strange but easy to reproduce.  I have asked Brymen if they can fill us in on what it's doing.

See Brymen's response below:

Quote
The digital reading and analog bargraph of BM780 DCV function come from different algorithm designs. Analog bargraph algorithm uses faster converter to get the peak averaging RMS (not True RMS) of the input signal. That is the reason why bargraph display speed is more faster than digital reading update speed. That is also the reason why bargraph algorithm can be with the mechanism to judge if the input DCV is with additional high ACV and if meter should auto switch to higher measuring range in case of being with high ACV. Nevertheless, its peak averaging RMS algorithm design is with a nature. While the DCV level is less than ACV peak, the bargraph will display ACV peak averaging RMS only. The bargraph will start to reflect DCV component only in case DCV level is higher than ACV peak. That is the reason why the bargraph appeared to lockup against your tests.     
[/i]


I haven't forgotten about this meter.  There was another question that arose when working on Part 4 and I wanted to get an answer to that before moving forward.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 01, 2020, 01:18:39 pm
Someone had posted this link, asking me if the new meter was going to be available January. 

https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)

To be clear, I don't have any inside knowledge as to when the meter is going to be available, what the cost will be or who will be distributing it.   Ultimately it's up to Brymen.  What I can tell you is that while working on Part 4, I had another question.  Brymen has written me and are looking into it. 

With this meter not being released yet, I would rather provide them with the opportunity to address anything that comes up.  They continue to be very responsive but again, making changes requires time.  Personally, I am glad that they are willing to take the time to investigate questions I have.   

Just a quick reminder.  I block posts with links to prevent using the channel for spamming ads.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on December 04, 2020, 05:22:43 am
Someone had posted this link, asking me if the new meter was going to be available January. 
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)
To be clear, I don't have any inside knowledge as to when the meter is going to be available, what the cost will be or who will be distributing it.   Ultimately it's up to Brymen.

The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 05, 2020, 12:03:46 am
Someone had posted this link, asking me if the new meter was going to be available January. 
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)
To be clear, I don't have any inside knowledge as to when the meter is going to be available, what the cost will be or who will be distributing it.   Ultimately it's up to Brymen.

The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.

What about price and release date?  Anything solid yet?
Title: Re: Handheld meter robustness testing
Post by: EEVblog on December 05, 2020, 12:34:14 am
Someone had posted this link, asking me if the new meter was going to be available January. 
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)
To be clear, I don't have any inside knowledge as to when the meter is going to be available, what the cost will be or who will be distributing it.   Ultimately it's up to Brymen.

The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.

What about price and release date?  Anything solid yet?

No release date yet, they are still working on it.
Like I said, I can sell it significantly under US$150. Reseller prices and amazon prices may vary.
For those who want it cheap sign up for my newsletter on the website and you'll get notified of a discount when it goes on sale.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on December 05, 2020, 02:01:30 am
The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.

I'm curious as to why neither you nor Brymen have a US distributor?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 05, 2020, 02:13:59 am
Someone had posted this link, asking me if the new meter was going to be available January. 
https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1 (https://www.welectron.com/Brymen-BM786-Multimeter-EEVBlog-Edition_1)
To be clear, I don't have any inside knowledge as to when the meter is going to be available, what the cost will be or who will be distributing it.   Ultimately it's up to Brymen.

The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.

What about price and release date?  Anything solid yet?

No release date yet, they are still working on it.
Like I said, I can sell it significantly under US$150. Reseller prices and amazon prices may vary.
For those who want it cheap sign up for my newsletter on the website and you'll get notified of a discount when it goes on sale.

Are you waiting on a final cost from Brymen?  Just curious as when I asked them about pricing, they also gave me a vague sort of answer.   A range based on other products.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 05, 2020, 02:15:47 am
The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.

I'm curious as to why neither you nor Brymen have a US distributor?

Greenlee and AMPROBE have rebranded some of their products.  Maybe there are others.   
Title: Re: Handheld meter robustness testing
Post by: Cliff Matthews on December 05, 2020, 02:19:46 am
The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.

I'm curious as to why neither you nor Brymen have a US distributor?

Greenlee and AMPROBE have rebranded some of their products.  Maybe there are others.
or maybe it's because he's a one man shop with 2 sons looking up to him? If he extends trust to a US rep to carry a $25K stock level on all his merch and a cash float of $10K to manage flow, one false move and someone may miss-out on college..
Title: Re: Handheld meter robustness testing
Post by: EEVblog on December 05, 2020, 08:42:01 am
The BM786 is exclusive to the EEVblog, it will not be sold under any other brand or dealer.
Welectron and Spark Labs/Simon's Electronics are the only dealers who will carry it.
You'll have to buy the BM789 or the lower model if you want the Brymen brand.
I'm curious as to why neither you nor Brymen have a US distributor?

Because there is no hassle selling into the US from Australia like there is to the EU.
If you are absolutely desperate and want it tomorrow in the US then I sell via Amazon, with Amazon US holding the stock. In fact I sell tons via Amazon US, so much so that I have a hard time keeping stock  levels up.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on December 05, 2020, 08:49:30 am
Are you waiting on a final cost from Brymen?  Just curious as when I asked them about pricing, they also gave me a vague sort of answer.   A range based on other products.   

They gave you a vuage answer because they don't set retail prices, and various dealers would likely have different FOB cost deals and different margins.
I've just been lazy and haven't worked out a final retail cost yet, is that ok?
Title: Re: Handheld meter robustness testing
Post by: Fungus on December 05, 2020, 02:29:57 pm
Like I said, I can sell it significantly under US$150.

Makes me wonder how much Fluke makes on every meter.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 05, 2020, 03:09:18 pm
Are you waiting on a final cost from Brymen?  Just curious as when I asked them about pricing, they also gave me a vague sort of answer.   A range based on other products.   

They gave you a vuage answer because they don't set retail prices, and various dealers would likely have different FOB cost deals and different margins.
I've just been lazy and haven't worked out a final retail cost yet, is that ok?
Of course that's fine. 

***
I assume my asking the question was ok as well?

It sounds like we will be back in business soon.   
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on December 05, 2020, 07:17:13 pm
Makes me wonder how much Fluke makes on every meter.

Hopefully enough to pay their employees well, cover their warranty and support obligations, and make every other DMM maker jealous of their profits.  >:D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 10, 2020, 01:09:16 am
New shipment is on it's way.   Hope to have a part 4 in a couple of weeks.       
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 12, 2020, 12:31:32 am
We are back in business.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 12, 2020, 10:44:14 pm
Testing is moving along.  Blowing the dust off the old test setup. 
Title: Re: Handheld meter robustness testing
Post by: tautech on December 12, 2020, 10:53:26 pm
 :-+
 :popcorn:
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on December 13, 2020, 01:31:43 am
Eager to see the results, joe.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 13, 2020, 02:53:47 am
My plan is to jam the remaining tests into one final video.

The last time I ran this test, I literally destroyed the meter I was looking at.  Outside of that one broken contact on the BM869s, it held up very well to the abuse.  We know Brymen runs a similar test in-house so I am not expecting any surprises, but that's why we test them.   
Title: Re: Handheld meter robustness testing
Post by: Cliff Matthews on December 13, 2020, 01:24:33 pm
Joe, any chance you could ask Brymen if they'd ever produce a meter with Polarity swapping diode check? (https://youtu.be/QEdTp1qtHBc?t=772)

I think this could require big changes to a meter's front-end, but I'd love to see if the FLIR DM92/3 would "come-a-gutza" under your hands! At this level it competes with Fluke, so if we could get Flir to send you one, it would be nice to know if the switch can take a good beating too. I bet you'd knock it out with the grill starter and send them back to the drawing board  :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 13, 2020, 03:05:06 pm
The channels far too small and I doubt I would have much influence with Brymen or any other company.   

It's also never going to be a feel good channel where I just talk about how great the products are and give them all five stars.  No company is going to want to see me looking at their products unless they have their shit together. 

https://www.youtube.com/watch?v=-tGL-buZ94Y (https://www.youtube.com/watch?v=-tGL-buZ94Y)
     

Maybe if you could get enough people to agree on features, you could go to them with the data.  I wonder what Flir's feedback had been.   I use diode check for a quick diode and transistor test.  I want to know that when I reverse it, the junction is open.  I will commonly use it to determine the pinout and if its NPN or PNP.   This switching doesn't seem like a well thought out idea.  More a marketing gimmick that did more harm than good.  Maybe you can shut it off.   That or use the resistor manual range.  Nice thing about the resistor mode, you may find a leaking part that you may not find with a standard diode test. 

You could use a small step down transformer, resistor and scope.  Get what ever voltage and current you want.   Now you can see how it behaves.  That odd ball Huntron I have works something like this.  I have the software for it now but have yet to do anything with it outside of scratch my head when I look at it.   :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 13, 2020, 03:52:05 pm
One fifth of the way into the test.  That's 10,000 full rotations, not that half rotation stuff.  I use my old HP 34401A to monitor the contact resistance directly.  If you are a fan of using post it notes to explain how to interpret the data, I have left the scales off the graph to make you feel more comfortable.   :-DD  I never did figure out what those numbers meant. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on December 13, 2020, 05:23:32 pm
Nice! Any grinding sounds yet?

I know, I know, I need to watch when it comes out, but the curiosity is killing me...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 13, 2020, 06:20:52 pm
After listening to the brand new Fluke 87V grind and chatter, Keysight's choice of a glass filled plastic spring cracking all four prongs, or Dave's 121 GW turning to dust, I fully understand why you would ask. 

This is the third Brymen product I have life cycled and based on the first two, I doubt we will see anything like this.  :-DD
Title: Re: Handheld meter robustness testing
Post by: Cliff Matthews on December 13, 2020, 07:03:10 pm
That's one classic but scary picture Joe. Just the thing needed for a handheld ball of plasma.  :scared:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 13, 2020, 08:39:36 pm
I doubt anyone expected much from the little ANENG meter's switch.   The UNI-T UT210Es I know people have bought are slowly failing due to their switches going intermittent.  I've seen three of them now.   Look at all the switch problems with the 121GW.  With so many combinations of shims and contact styles, that meter went through a lot of revisions and it still turned to dust.     Of the nine meters I have life cycled, the Fluke 17B+ out performed them all.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 14, 2020, 07:57:53 pm
A bit over 30,000 full cycles now.   Poor meter.

***

It's been running almost two and a half days now.  It's very close to being finished. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 16, 2020, 01:21:45 pm
Life cycle testing is complete.  I still have two more tests that need to be ran and then the long boring task of compressing a solid week into an hour... 

Getting close.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 17, 2020, 01:58:16 pm
A bit of a spoiler but should hold a few of you over until we get things finished up. 

What's some of the new Brymen meter's contacts look like after 50,000 full cycles or it you like, Dave's 100,000 cycles?  I think it's pretty clear, it's no Aneng.     

I had ran across another small problem during my testing and they have sent out and update that should arrive very soon.  I have ran enough tests on the meter now that I am confident this will be the last of it.  The Brymen engineers have really been doing a great job keeping up the pace.     

Of course, the firmware updates have been a bit of a pain.  So if you're wondering if the old white haired EE can still solder... 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on December 17, 2020, 03:57:32 pm
It's no Aneng indeed. Quite the impressive contrast.
Regarding the firmware, you are the perfect beta tester- I could only dream of having this level of scrutiny in my previous job. :-+
Title: Re: Handheld meter robustness testing
Post by: Cliff Matthews on December 17, 2020, 08:50:30 pm
That white haired EE sure solders-up some sexy looking fillet's  :-+  Do we get to see this hard work before Christmas?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 18, 2020, 01:44:17 am
Assuming the parts show up soon and this last round of testing goes smoothly,  I think we are about a week out. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 22, 2020, 01:34:55 pm
I noticed yesterday that someone had started up a non-related discussion inside this thread, I'm guessing to get noticed.   Today it was moved into it's own area.  As far as I know, that was a first for this thread.   I assume the sudden interest in keeping this thread clean is because the focus has been on what should be a new EEVBLOG product.   Anyway, I appreciate the help.   

I checked the tracking for the latest updates and it shows the package was delivered.  We haven't had any problems with shipping before but with Christmas around the corner, shipping can be a bit of a problem.   Hopefully it was just transfered to another local carrier and the package is still in transit.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 22, 2020, 08:18:47 pm
Our neighbor received some strange package.   They don't have the best of eyesight, and after opening it and seeing the little anti static bags, gave us a call. 

Time to warm up the iron one last time. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 23, 2020, 02:13:04 am
Not enough coffee and I wasn't paying attention to where the iron was.   One meter has had 4 ICs installed on it and it's starting to take a toll on the copper. 

All three meters are back together and I ran back through all the tests off camera.  It looks like Brymen has a good handle on it.  Time to finish up this testing.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 27, 2020, 06:17:43 pm
https://www.youtube.com/watch?v=UY9Myo5ngPQ (https://www.youtube.com/watch?v=UY9Myo5ngPQ)

The spreadsheet has also been updated to include the Brymen BM786.


Quote
Does any brymen meter beep in diode mode like fluke
Apparently this person believes Fluke only makes one product or that all Fluke products behave the same.   

At least one person noticed that I demonstrated the diode beep mode and there's always the manual.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 23, 2021, 11:22:11 am
This person has a few videos covering the basics on generators.   Keep in mind, by design I ignore the current waveform requirements and limit the energy to about 20J and I wanted something programmable.     

Check out his channel if you want to learn more about it.
https://www.youtube.com/watch?v=V3R55RvZf_Y (https://www.youtube.com/watch?v=V3R55RvZf_Y)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 20, 2021, 11:57:32 am
Brymen are sending the parts to update my BM789 to the latest revision.  Once these arrive, I plan to go ahead with the review. 

***
The parts have arrived.  One step closer.

***
Getting ready to replace the controller with the latest firmware.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 27, 2021, 06:02:14 pm
I have finished with the updates to the BM789 and ran through a basic functional test.  It seems no worse for the wear.   I plan to start working on the review this weekend.  With it being very similar to the BM786, I plan to forego the drop, chemical and selector switch life cycle test.   If there is anything specific anyone would like to see, feel free to ask. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 03, 2021, 07:15:17 pm
The meat packing box is box out.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 04, 2021, 03:17:27 am
It's the middle of summer and the office is fairly warm.  Even with all the insulation, the small Peltiers are having a difficult time reaching -5C. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 04, 2021, 11:22:51 am
It's the middle of summer and the office is fairly warm.  Even with all the insulation, the small Peltiers are having a difficult time reaching -5C.
If you were making money out of these tests, a chest freezer would be your christmas gift!  :-+
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 05, 2021, 12:13:13 am
I had seen a small compressor type cooler that looked like it would be perfect for this kind of work.   

Consider I held the meter at -5 / 60C for a half hour.  It took about 6 hours to cool down to -5.  Ramp up was about an hour.   Basically it's a full day.   Now the best part, that's about 1 minute of video!    :-DD   It's actually a worse time ratio than the switch life test.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 05, 2021, 03:39:49 am
I may show off my vintage Fluke 8506A that I saved from the dumpster to compare the AC performance.   This meter has a thermal RMS converter.   It needed some repairs and I had using my old HP34401A to do a poor mans alignment on it, except for the AC sections.    The AC specs on this meter far exceed anything I own and I suspect I would have done more harm than good. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2021, 03:10:47 am
We ran into a bit of a snag with the BM789.  Brymen suspects the problem is alignment related caused from changing out the IC to update the firmware.  They are providing a brand new BM789 which should address it.   

Because it'sonly the alignment,  I plan to continue with some of the other tests (battery life, transients...) where this isn't critical.  Hopefully I can at least keep the effort moving ahead.     

This is what happens when you do more than unbox a product, provide a half hour blab fest and give it five stars.  So be patient. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2021, 08:01:42 pm
A brand new BM789 arrived.   

Good job Brymen.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2021, 12:41:03 pm
The Brymen BM789.

https://www.youtube.com/watch?v=ciwBB5kYvJM (https://www.youtube.com/watch?v=ciwBB5kYvJM)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2021, 12:45:09 pm
This video is for you vintage analog collectors. 

https://www.youtube.com/watch?v=b7k4ZFJ2v4I (https://www.youtube.com/watch?v=b7k4ZFJ2v4I)
Title: Re: Handheld meter robustness testing
Post by: Cymaphore on August 16, 2021, 03:00:51 pm
Thank you for the great video! Your videos are really a different class of review.

About the resistor autoranging test: When I tried to make a comparison of the B1023 autoranging performance, I used a couple of photo resistors (demonstrated here (https://youtu.be/WdO9O-_fl3I?t=844)). Two of them, and maybe more, can be easily trimmed to near equal values to compare meters in an insulated fasion without transistor sideeffects.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 05:26:02 am
I doubt using better resistors and a good relay would make any difference for the settling time.   Originally, I would just short them but it seems Dave had posted some data with a 10 ohm and I follow suit to try and get a decent comparison.   

There was a person who had posted about trying to use one of my videos to come up with an actual time.  After that I setup a high speed camera with a counter as a reference.  at 1000fps, you would watch the LCDs operate.   It was fairly accurate but not very useful information, to me anyway. 
Title: Re: Handheld meter robustness testing
Post by: Cymaphore on August 17, 2021, 09:42:21 am
I doubt using better resistors and a good relay would make any difference for the settling time.   Originally, I would just short them but it seems Dave had posted some data with a 10 ohm and I follow suit to try and get a decent comparison.   

There was a person who had posted about trying to use one of my videos to come up with an actual time.  After that I setup a high speed camera with a counter as a reference.  at 1000fps, you would watch the LCDs operate.   It was fairly accurate but not very useful information, to me anyway.

I don't think it would impact the settling time, but I wanted something that is as close to a bare resistor as possible. That's why I tried out that LDR-solution.

Operating multiple LDRs by a single light source is a nice thing. Depending on the LDR in question it can be controlled quickly and on a very wide range. The ones that I used for toying have ~6 kOhm (Full brightness) to ~600k Ohm (Complete darkness), with a little tweaking that touches 4 resistance ranges on the BM789 and it can be controlled quickly and easily by just changing a single light source.

Other LDRs have different ranges.

But you're correct, for your test it probably would not make any difference. I just wanted to mention it, because it was really interesting for me to compare the B1023 to the BM789 in that way and it is maybe a good idea in case you ever need such kind of a controllable resistor.
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 11:18:49 am
I uses a opto-fet for switching a resistor in when testing DMM's, this way I avoid any noise or leak current and because it is a dual-fet I can also use it for capacitance ranges.
Instead of comparing different meters I find how long time I need to switch the resistor on before the meter will measure it correctly, this is easier to do and more precise, but it would not look as interesting on video.

My circuit: https://lygte-info.dk/info/DMMTesterACSwitch%20UK.html (https://lygte-info.dk/info/DMMTesterACSwitch%20UK.html)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 12:23:30 pm
The only use I had for an LDR with the meters was to detect the ambient light for controlling the backlight of a check UNI-T meter.   

I was wanting to run the meter's entire range consistently.


I uses a opto-fet for switching a resistor in when testing DMM's, this way I avoid any noise or leak current and because it is a dual-fet I can also use it for capacitance ranges.
Instead of comparing different meters I find how long time I need to switch the resistor on before the meter will measure it correctly, this is easier to do and more precise, but it would not look as interesting on video.

My circuit: https://lygte-info.dk/info/DMMTesterACSwitch%20UK.html (https://lygte-info.dk/info/DMMTesterACSwitch%20UK.html)

You want to avoid leak current but stick a 10M probe across it?  I wanted to see the meters go full open range on down.   The scope may show the current source changing but it won't show the meter settling.  Dave's 121GW was interesting in that one of the things they were constantly doing was playing with the software filters.  It was easy to detect with the camera. 

I had not thought about trying to look at the capacitance this way.  Some of the meters are again VERY slow to settle at the lower ranges. 

Fully agree about the scratching leads not being a very useful way to compare them which was why I started using something a bit more controlled.   
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 12:30:25 pm
You want to avoid leak current but stick a 10M probe across it? 

No, the probe was only to because I wanted to show the curve, in real test I do not stick anything across.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 02:10:14 pm
Quote
Instead of comparing different meters I find how long time I need to switch the resistor on before the meter will measure it correctly, this is easier to do and more precise, but it would not look as interesting on video.

I'm not understanding your above comment.   If you do not time them with the scope, I doubt leakage would be a problem with these handhelds.   Without the scope, I assume you monitor the settling with the display.   How is what you are doing more precise.  I guess I need to take the time to read your entire blog. 

With your jig using a 10uF, I guess I don't see the point of the two FETs.   I was looking my fixture using the first four meters and capacitance was about 1nF.  Even with these large vintage FETs (I think I have some BUZ parts in there), 10uF would be no problem to switch in.   

The meters do not always use the same polarity and I need to flip the leads which is where the dual FET would be an improvement.       
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 02:24:50 pm
Quote
Instead of comparing different meters I find how long time I need to switch the resistor on before the meter will measure it correctly, this is easier to do and more precise, but it would not look as interesting on video.

I'm not understanding your above comment.   If you do not time them with the scope, I doubt leakage would be a problem with these handhelds.   Without the scope, I assume you monitor the settling with the display.   How is what you are doing more precise.  I guess I need to take the time to read your entire blog. 

There is no reason to look at the pulse, I know the pulse with from my generator and when the pulse width is long enough for the meter to get a correct reading I have my time. With some meters this time varies a bit and I increase the time until I get a stable reading for each pulse.

With your jig using a 10uF, I guess I don't see the point of the two FETs.   I was looking my fixture using the first four meters and capacitance was about 1nF.  Even with these large vintage FETs (I think I have some BUZ parts in there), 10uF would be no problem to switch in.   

Many meters uses some sort of AC to measure capacitors, with two FETs I switch both polarities on/off.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 02:52:56 pm
Quote
Instead of comparing different meters I find how long time I need to switch the resistor on before the meter will measure it correctly, this is easier to do and more precise, but it would not look as interesting on video.

I'm not understanding your above comment.   If you do not time them with the scope, I doubt leakage would be a problem with these handhelds.   Without the scope, I assume you monitor the settling with the display.   How is what you are doing more precise.  I guess I need to take the time to read your entire blog. 


There is no reason to look at the pulse, I know the pulse with from my generator and when the pulse width is long enough for the meter to get a correct reading I have my time. With some meters this time varies a bit and I increase the time until I get a stable reading for each pulse.

Again, I guess I am missing the your point of it being more precise.  More precise than scratching the leads?  More precise than using a high speed camera with a clock for a reference?   

Does it not look as interesting as what on video?  Scratching the leads?

Looks like are basically doing the same thing. 

With your jig using a 10uF, I guess I don't see the point of the two FETs.   I was looking my fixture using the first four meters and capacitance was about 1nF.  Even with these large vintage FETs (I think I have some BUZ parts in there), 10uF would be no problem to switch in.   

Many meters uses some sort of AC to measure capacitors, with two FETs I switch both polarities on/off.

I assume you ran into problems with some meters when turning off the single FET and the meter still reading the 10uF or some other high value.   I had looked at four of the meters using a 10uF in series with the single FET and it seemed fine.  Any idea which meters had the problem with the single FET?  Maybe I have one.   
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 03:56:58 pm
Quote
Instead of comparing different meters I find how long time I need to switch the resistor on before the meter will measure it correctly, this is easier to do and more precise, but it would not look as interesting on video.

I'm not understanding your above comment.   If you do not time them with the scope, I doubt leakage would be a problem with these handhelds.   Without the scope, I assume you monitor the settling with the display.   How is what you are doing more precise.  I guess I need to take the time to read your entire blog. 


There is no reason to look at the pulse, I know the pulse with from my generator and when the pulse width is long enough for the meter to get a correct reading I have my time. With some meters this time varies a bit and I increase the time until I get a stable reading for each pulse.

Again, I guess I am missing the your point of it being more precise.  More precise than scratching the leads?  More precise than using a high speed camera with a clock for a reference?   

Does it not look as interesting as what on video?  Scratching the leads?

Looks like are basically doing the same thing. 

With my method I do multiple tests, this means I do not risk getting the fastest time the meter can do.

Looking at a couple of meter and seeing which is fastest may be more interesting for some, I like the numbers because I can compare all the meters I have tested (>100). If you measure frames you can, of course, do the same, except for continuity.

With your jig using a 10uF, I guess I don't see the point of the two FETs.   I was looking my fixture using the first four meters and capacitance was about 1nF.  Even with these large vintage FETs (I think I have some BUZ parts in there), 10uF would be no problem to switch in.   

Many meters uses some sort of AC to measure capacitors, with two FETs I switch both polarities on/off.

I assume you ran into problems with some meters when turning off the single FET and the meter still reading the 10uF or some other high value.   I had looked at four of the meters using a 10uF in series with the single FET and it seemed fine.  Any idea which meters had the problem with the single FET?  Maybe I have one.   

I did not bother checking capacity before I had the AC switch, only disconnecting one way may lead to errors (I have no idea if it do, I have never bother comparing).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 04:28:28 pm
With my method I do multiple tests, this means I do not risk getting the fastest time the meter can do.

Looking at a couple of meter and seeing which is fastest may be more interesting for some, I like the numbers because I can compare all the meters I have tested (>100). If you measure frames you can, of course, do the same, except for continuity.

I used a frequency counter, tied to the arb that would output a 1kHz clock once triggered.   The counter is cleared on start and counts up while with a 1mS resolution.    The load is applied or removed at the trigger time.    The camera has just shy of a 1000fps sample rate.  With this setup, I can get some decent numbers if it were needed.   I can run up to three meters this way in parallel and it makes no difference as far as the absolute data that could be collected.  I'm looking at what was captured with the camera is all.   The fact we can see the meters side by side real time is just an added plus.   

The downside to this method is my camera can only capture in bursts of two seconds.  I currently trigger the camera using the same trigger.  Some meters take longer than this to settle.  In these cases, I have used the cameras manual post trigger to capture the data.   A pain.   I had written the guy who designed that high speed camera when he announced the prototypes and offered to buy one.  That camera would have been a big help with the testing.  He gave them away as part of a promo.  Dave did a review of the one that was sent him. 

I understand you want numbers and are your not using the scope to get them.  I understand your jig, tied to the arb but I am not understanding how you make this precise measurement.  Could you please explain how you actually get the settling time?

I did not bother checking capacity before I had the AC switch, only disconnecting one way may lead to errors (I have no idea if it do, I have never bother comparing).

So you haven't checked if there was actually a problem with the single FET.  More just trying to prevent a possible problem.  Makes sense.  Adding a capacitor may be of interest but I would like to go down to 200pF ish   and up around 1000uF   as most of the meters I have looked where slowest at the two extremes.
 
 
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 05:31:47 pm
Could you please explain how you actually get the settling time?

When the pulse is long enough for the meter to show the correct value (It is easy enough to do a long pulse first to see what the correct value is).

So you haven't checked if there was actually a problem with the single FET.  More just trying to prevent a possible problem.  Makes sense.  Adding a capacitor may be of interest but I would like to go down to 200pF ish   and up around 1000uF   as most of the meters I have looked where slowest at the two extremes.

I do not bother with the small values for speed tests, but test up to 70mF if the meter supports it. I have a few large capacitor I use to test with and decades/PCB's with lower values.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 06:25:14 pm
I think I get it.  So you keep changing the pulse time until you find the spot where the meter is stable, triggering each time.   To get any sort of precision it must take a very long time to run.   If you had a way to monitor the meter (HS camera) one long pulse and you would have it.
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 06:47:31 pm
I think I get it.  So you keep changing the pulse time until you find the spot where the meter is stable, triggering each time.   To get any sort of precision it must take a very long time to run.   If you had a way to monitor the meter (HS camera) one long pulse and you would have it.

It takes a few minutes, precision is not really an issue (2.5s or 2.53s do not matter).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 08:25:44 pm
I think I get it.  So you keep changing the pulse time until you find the spot where the meter is stable, triggering each time.   To get any sort of precision it must take a very long time to run.   If you had a way to monitor the meter (HS camera) one long pulse and you would have it.

It takes a few minutes, precision is not really an issue (2.5s or 2.53s do not matter).

30fps or 33ms would do it.  Basically any cell phone should handle it.  One cycle would get you there.  Maybe a counter in the background for the time reference. 

***
Does seem like with your eyes being used for the  feedback, 30ms error would be conservative.   Maybe not. 
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 17, 2021, 08:32:58 pm
I think I get it.  So you keep changing the pulse time until you find the spot where the meter is stable, triggering each time.   To get any sort of precision it must take a very long time to run.   If you had a way to monitor the meter (HS camera) one long pulse and you would have it.

It takes a few minutes, precision is not really an issue (2.5s or 2.53s do not matter).

30fps or 33ms would do it.  Basically any cell phone should handle it.  One cycle would get you there.  Maybe a counter in the background for the time reference.

I am not sure it would be faster that way.
And as I have already said: The measure time varies (At least for some DMM's).


Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2021, 08:37:18 pm

I am not sure it would be faster that way.
And as I have already said: The measure time varies (At least for some DMM's).

Does seem like with your eyes being used for the  feedback, 30ms error would be conservative.   Maybe not.   Camera would let you run more than one meter at a time plus better precision?    What meters do you have that vary? 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2021, 01:48:59 am
Using a 10uF, even at 250fps, it's a bit difficult to tell what you would call settling with the BM789.     I think you would need to define how you measure it.  Is it when the display first shows the correct answer even though it may not be readable with the human eye, or when the display is actually fully turned on.  It takes about 100mS just for the display to settle after showing the correct number.   I guess it depends what precise means to you.   

Personally, just seeing how a few of them compare side by side is gives a good enough indicator.     
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 18, 2021, 11:26:19 am

I am not sure it would be faster that way.
And as I have already said: The measure time varies (At least for some DMM's).

Does seem like with your eyes being used for the  feedback, 30ms error would be conservative.   Maybe not.   Camera would let you run more than one meter at a time plus better precision?    What meters do you have that vary?

The timing is the pulse width before the meter can read the value each time, the time the meter needs to display the value is not included.

I have not noted what meters varies, I simply adjust the time until I get a reading each cycle. With ohm the variance is usually small, but when doing continuity it easily triple (or more) the reaction time.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2021, 11:55:23 am

I am not sure it would be faster that way.
And as I have already said: The measure time varies (At least for some DMM's).

Does seem like with your eyes being used for the  feedback, 30ms error would be conservative.   Maybe not.   Camera would let you run more than one meter at a time plus better precision?    What meters do you have that vary?

The timing is the pulse width before the meter can read the value each time, the time the meter needs to display the value is not included.

I have not noted what meters varies, I simply adjust the time until I get a reading each cycle. With ohm the variance is usually small, but when doing continuity it easily triple (or more) the reaction time.

Your using the display for visual feedback so of course the time for the meter needs to display the value is included.  But the time that your eyes will detect it seems like it can vary depending on you.  The time for the 789 to show the value dimly on the display vs fully on is about 100ms.   

I assume what you are calling reaction time is the time from when the load is applied across the meter to when the meter displays the value and you are able to see it.  With the continuity being so much faster then when measuring resistance, even if the variance is the exact same time, we would expect the percentage to be much higher for continuity. 

I looked over your blog and couldn't make sense of it. The video is nice as the viewers can easily see how the meter compares side by side.   
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 18, 2021, 06:19:58 pm
Your using the display for visual feedback so of course the time for the meter needs to display the value is included.  But the time that your eyes will detect it seems like it can vary depending on you.

I have explained how I do it and that explanation do not need to include my reaction time.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2021, 11:28:36 pm
I certainly believe you feel you have explained it well enough,  but details mater.    No matter though. 

Video of the 121GW prototype and the Gossen with the counter taken at 1000fps.   
https://youtu.be/13nv-NsQXDs?t=118

I tried one with the BM789 and can pulse it to where I can clearly see with the high speed camera that the display is showing the correct value but only for a few frames.  It's fast enough that the LCD does not reach maximum contrast.  Some human eyes may miss it.   I would imagine that some meters may hold the data up longer once the meter has settled.   As we saw with the 121GW, you may get the first few digits shortly after applying the load but it can take a very long time to settle.   IMO, the text should be written such to handle all of these cases and explain it in detail what the criteria is.     
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 19, 2021, 04:42:48 pm
The spreadsheet has been updated to include data from the BM789.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 05, 2021, 07:45:16 pm
I've shown the open circuit voltage waveform I apply to test the meters many times but I have never shown the current.   If you were curious and afraid to ask, this video is for you.  For you vintage TE collectors, you can see my 1960's Tektronix in operation.  Not a bad probe for it's age.     

https://www.youtube.com/watch?v=3LW8N9cl6Wk (https://www.youtube.com/watch?v=3LW8N9cl6Wk)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 06, 2021, 03:48:43 am
It's been a while since anyone has asked me about looking at the UNI-T UT61e+.   It's been available long enough that I assume the interest in it has died down but the one comment this last video had was once again asking about this meter.   

While I have vowed never to purchase another UNI-T (unless it were an improved UT181A) because of their poor track record, if you want to see this particular meter ran, let me know.   Maybe there are still some UNI-T fan boys out there who still believe??

Dave's review showing the internals: 
https://www.youtube.com/watch?v=ZxzQZFRznp0 (https://www.youtube.com/watch?v=ZxzQZFRznp0)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 07, 2021, 12:27:55 pm
Dave did a pretty good job with the overall review and made it pretty clear that the value wise, it's not a good choice.  It may have curbed some of the interest. 

For the few of you who still want to see it, we could treat it as a special case and deviate from the normal tests to try and keep it alive (don't expose it to any ESD).   I have never life cycled any of the UNI-T products.   It may be interesting to see how it holds up.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 07, 2021, 11:25:19 pm
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD


Title: Re: Handheld meter robustness testing
Post by: Fungus on September 08, 2021, 01:23:37 am
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD

Correct.

I mean, seriously, what is the point of testing the UT61E for "robustness"? We all know it isn't.


Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 08, 2021, 02:21:57 am
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD

Correct.

I mean, seriously, what is the point of testing the UT61E for "robustness"? We all know it isn't.
At first glance yes. The UT61E (and probably the UT61E+) are finicky with transients but why not put it through its paces? Who knows? Perhaps it could be an additional advantage of the "plus" model...

Obviously that the "real" test would be with the "third party plus-certified and mega-accredited and über-listed" UT161E, but that is in another price league...

At any rate, I don't think there is much to be lost, especially after you already beaten to death the UT61E original, with excellent suggestions to increase its robustness.

(edit) Kerry Wong also did a teardown of the UT61E+
http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/ (http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/)

(edit2) Tenma has some discounts on beefed up UT61E (non plus)
https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/ (https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/)
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on September 08, 2021, 04:49:34 am
I realized some time ago that if Joe runs it, I'll watch it. There's been quite a few meters that I really had no interest in ever owning, but I still find their point of failure and Joe's analysis interesting. I really appreciate his systematic approach. There have been a few surprises along the way too.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 08, 2021, 12:27:35 pm
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD

Correct.

I mean, seriously, what is the point of testing the UT61E for "robustness"? We all know it isn't.
At first glance yes. The UT61E (and probably the UT61E+) are finicky with transients but why not put it through its paces? Who knows? Perhaps it could be an additional advantage of the "plus" model...

Looking at the data I've collected,  of the eight UNI-T products I looked at, half never made it past the ESD, AC line tests.    During the EEVBLOG review for the 61E+, Dave focuses on the lack of a surge rated resistor.   The UT181A is the same and survived some decent hits after a few small changes.    Dave talks about the new ground path.   It could help but my guess is it won't.   

Obviously that the "real" test would be with the "third party plus-certified and mega-accredited and über-listed" UT161E, but that is in another price league...

That meter would fail ESD just like the stripped down version.   

At any rate, I don't think there is much to be lost, especially after you already beaten to death the UT61E original, with excellent suggestions to increase its robustness.

For you, skim the video for a few seconds and your done.    Flip side, it takes fair amount of my time to run the tests and edit the videos.  For this meter, assuming the grill starter kills it, maybe six days.   Half of that would be cycling the function switch.   
 

(edit) Kerry Wong also did a teardown of the UT61E+
http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/ (http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/)

(edit2) Tenma has some discounts on beefed up UT61E (non plus)
https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/ (https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/)

Skimmed the Kerry Wong video but didn't notice anything beyond what Dave had gone over. 

We could reorder the tests for this special meter.  Start with the 100us transients.  If it survives  that (which it won't) then run the AC line test and then the ESD.  Not sure we would learn anything more doing this.  The end results the same. 

UNI-T fanboys are already thinking I am biased against this meter.  I can see the mass of down votes. lol.  I have more than enough data now to know what to expect. 

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 08, 2021, 12:35:52 pm
The green was a bit odd but now blue as well??    Is blue better? 

https://youtu.be/bxluPKhyOUU?t=1738

Title: Re: Handheld meter robustness testing
Post by: Nixfried on September 08, 2021, 12:45:42 pm
Hey Joe,

i was one of the few who voted against doing these kind of videos. (Seems like years ago...)
If i could vote again, i would definitely change my answer.
Just wanted to say that your videos are awesome, please keep them coming.

Just a little question regarding the BM869s:
I am using my BM869s to discharge capacitors before working on them(Through capacitance mode). In the manual brymen only states that
large value capacitors should be discharged through an appropriate resistive load. What is your opinion on this?

Best regards,
Tim
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 08, 2021, 01:12:12 pm
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD

Correct.

I mean, seriously, what is the point of testing the UT61E for "robustness"? We all know it isn't.
At first glance yes. The UT61E (and probably the UT61E+) are finicky with transients but why not put it through its paces? Who knows? Perhaps it could be an additional advantage of the "plus" model...

Looking at the data I've collected,  of the eight UNI-T products I looked at, half never made it past the ESD, AC line tests.    During the EEVBLOG review for the 61E+, Dave focuses on the lack of a surge rated resistor.   The UT181A is the same and survived some decent hits after a few small changes.    Dave talks about the new ground path.   It could help but my guess is it won't.   
The impact of a transient would be highly dependent on many factors - a certain Joeqsmith even said once that it is very hard to evaluate the robustness by looking at a PCB... :)

Obviously that the "real" test would be with the "third party plus-certified and mega-accredited and über-listed" UT161E, but that is in another price league...

That meter would fail ESD just like the stripped down version.   
Indeed ESD is a different kind of beast.

At any rate, I don't think there is much to be lost, especially after you already beaten to death the UT61E original, with excellent suggestions to increase its robustness.

For you, skim the video for a few seconds and your done.    Flip side, it takes fair amount of my time to run the tests and edit the videos.  For this meter, assuming the grill starter kills it, maybe six days.   Half of that would be cycling the function switch.   
And don't I know that? It seems the more effort put on a video, the lesser the audience watches thoroughly. Anything related to multimeters or consumer products goes a long way on my channel, but everything else does not go very far w.r.t. audience and retention. Or perhaps it is me. (oh, the mysteries of life...)

At the end of the day, do whatever you want to do with regards to testing. I think that, even if the audience/return is small, someone will use the knowledge to something better (at least that is why I convince myself to keep doing the videos I like and not only the ones that have the further reach).

We could reorder the tests for this special meter.  Start with the 100us transients.  If it survives  that (which it won't) then run the AC line test and then the ESD.  Not sure we would learn anything more doing this.  The end results the same. 
Well, every test exposes a level of weakness - the ESD is quite violent but less energy. IIRC the cert agencies are mostly concerned about the transients (or not, don't quote me on that), I would imagine more meters would survive further in your round of tests.

UNI-T fanboys are already thinking I am biased against this meter.  I can see the mass of down votes. lol.  I have more than enough data now to know what to expect.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 08, 2021, 02:58:16 pm
Hey Joe,

i was one of the few who voted against doing these kind of videos. (Seems like years ago...)
If i could vote again, i would definitely change my answer.
Just wanted to say that your videos are awesome, please keep them coming.

I don't take offense to it and being from Germany, I'm sure you didn't like me showing off your countries top engineering efforts at Gossen. 

It's never been a real popular subject anyway but I still find it interesting.

Just a little question regarding the BM869s:
I am using my BM869s to discharge capacitors before working on them(Through capacitance mode). In the manual brymen only states that
large value capacitors should be discharged through an appropriate resistive load. What is your opinion on this?

Best regards,
Tim

My opinion is that your question is very generic.   With the lack of constraints as a general rule I suggest you get in the habit of always discharging any capacitor before connecting it to any meter.   While I've had some very ignorant people suggest I was directly discharging capacitors into these meters, it's never been the case.   Still the tests do seem to indicate that some meters may handle a direct discharge better than others. 

For a worse case, you could try it with a DC supply.   Say for example your caps are charged to 1kV worse case.   You need about an ampere.   Roughly 2kohms (PTC + surge rated resistor) with 2X clamps, or 1kV/1kohms.  Maybe cycle the meter through all the modes (assuming you will as some point be in the wrong mode when you connect them).    If the meter survives this, you should be fine (until you have one charged to 2kV).    Keep in mind, 1kV @ 1A could prove lethal.     1kV may be enough to damage the contacts if you do it live.   Dave made a video about this after someone had damaged a 121GW.  I made a couple of counter videos to make the point.  To get some idea, see the attached video. 

Say your worse case was instead 100V.   You know I test every function of the meters with a full wave rectified 220V.  That's with every function selected.   It's killed a few meters but rare.   No Brymens I have looked at were ever damaged from this test.

https://www.youtube.com/watch?v=6j8i3LfKm5A (https://www.youtube.com/watch?v=6j8i3LfKm5A)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 08, 2021, 03:41:52 pm
The impact of a transient would be highly dependent on many factors - a certain Joeqsmith even said once that it is very hard to evaluate the robustness by looking at a PCB... :)

True but in this case I am drawing from my years of looking at UNI-T products in detail.   Not everyone's educated guesses will carry the same weight.   We can certainly run it as I normally would.  The meter will fail or I will once again eat crow.  :-DD   


And don't I know that? It seems the more effort put on a video, the lesser the audience watches thoroughly. Anything related to multimeters or consumer products goes a long way on my channel, but everything else does not go very far w.r.t. audience and retention. Or perhaps it is me. (oh, the mysteries of life...)

My two most popular videos show an old FPGA based CPU prototyping board I had wired by hand and a low cost handheld VNA.   

I am scratching my head why the channel has so many subscribers. Ads are turned off, so YT doesn't promote it.  I don't advertise outside of EEVBLOG.  My videos are not released on any sort of schedule and months can go by without making one.   It's maybe the worse way to run a channel.   :-DD  Combine all that with I am no showman.   You're never going to hear:  Please give it a thumbs up and join my Patreon so I can continue to bring you these high quality videos.    :-DD   

***
SP
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 08, 2021, 06:36:36 pm
I am scratching my head why the channel has so many subscribers. Ads are turned off, so YT doesn't promote it.  I don't advertise outside of EEVBLOG.  My videos are not released on any sort of schedule and months can go by without making one.   It's maybe the worse way to run a channel.   :-DD  Combine all that with I am no showman.   Your never going to hear:  Please give it a thumbs up and join my Patreon so I can continue to bring you these high quality videos.    :-DD   
You did something that nobody did before, so there's that. Also, EEVBlog forums are primed for test gear, therefore solely promoting this here is already a tremendous leg up. The fact you don't give a hoot for brand loyalty is another factor. At last, a bit of controversy (the subject of this poll) stirs the audience, including the fanboys that will throw tomatoes at the screen. :-DD

Although I am monetizing my channel, I don't have any hopes of it becoming a true source of income (the first US$100 only after 13 months - yay!) and could easily gather more audience speaking a language less uncommon than Portuguese. On the other hand, I do this for the love of the trade and to spread some of this knowledge to my fellow countrymen (or languagemen, as Portugal, Angola and others also watch).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 08, 2021, 11:08:39 pm
Although I am monetizing my channel, I don't have any hopes of it becoming a true source of income (the first US$100 only after 13 months - yay!) and could easily gather more audience speaking a language less uncommon than Portuguese.

You owe me a coffee.  Mine just came out my nose.   

The question now is how much was spent during that time?   :-DD   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 09, 2021, 03:02:14 am
Although I am monetizing my channel, I don't have any hopes of it becoming a true source of income (the first US$100 only after 13 months - yay!) and could easily gather more audience speaking a language less uncommon than Portuguese.

You owe me a coffee.  Mine just came out my nose.   

The question now is how much was spent during that time?   :-DD
Pssst! I can't say it out loud...

Seriously, in the year-and-a-half of the virus not much was spent - mostly freight here and there. Throughout the history of the channel I have been buying dirt cheap gear from and selling it back to the local market after doing the videos and some restoration, so the losses are very low. Also, those dirt cheap chinese multimeters are sold for almost the same price (after all they are practically new), so no significant loss is found there as well.

Overall the drive is not the money, but it surely helps and can materialize in more content to be shown.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 09, 2021, 12:37:49 pm
Since the virus, I've slowed my spending.  Some forced by lack of available parts.   This is the first new meter I have purchased.   Sadly, there isn't much of a market for damaged DMMs.  If I had no ethics I would peddle them.   Some of them still look new, in the box.  Sold as non-working, looks new,  I don't have the ability to test them,  no returns.    :-DD   The one I had salvaged for parts to give to another forum member, they couldn't bother to say thank you.  After that, all the damaged ones head to the recycle bins, which is where this meter will soon be heading as well.   :-DD
Title: Re: Handheld meter robustness testing
Post by: Kosmic on September 09, 2021, 01:39:53 pm
I am scratching my head why the channel has so many subscribers. Ads are turned off, so YT doesn't promote it.  I don't advertise outside of EEVBLOG.  My videos are not released on any sort of schedule and months can go by without making one.   It's maybe the worse way to run a channel.   :-DD  Combine all that with I am no showman.   You're never going to hear:  Please give it a thumbs up and join my Patreon so I can continue to bring you these high quality videos.    :-DD   

***
SP

Even though YT don't promote your channel you end up popping up if you search specific subjects or watch really niche videos, they are going to propose your videos on the side. I guess they want the viewer to stay on the platform even if they are not directly making any money with your videos.

For some reason I found your videos on YT before this thread.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 11, 2021, 10:29:36 pm
The UNI-T UT61E+   

https://www.youtube.com/watch?v=4rADgFqFFH8 (https://www.youtube.com/watch?v=4rADgFqFFH8)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 11, 2021, 10:59:52 pm
Yikes!  How many volt-Hz is that--3 billion or so? 

On the plus side, perhaps this could be a useful desoldering technique.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 11, 2021, 11:12:50 pm
Sort of a Metcal iron.   

Obviously I wasn't thinking too much about damaging the meter.  Looks like minimum, 4 X PTCs and 4 X transistors would need to be replaced but the PCB seems in  good shape.     

Maybe our friends from China will decode that box for me.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 12, 2021, 01:48:51 am
On the video you nailed the interesting bits of the UT61 series: the lightning fast capacitance meter (the original UT61E is the king on this, even on capacitors with tens of thousands of µF) and its wide input frequency (which cooked the frequency range unfortunately). I did not improve the safety on mine since, as long as I keep it on the bench, I don't see it being cooked anytime soon. Also, the absence of an auto-power off is great.

Back to the frequency range, the UT61E+ manual (https://www.uni-trend.com/uploadfile/2020/1101/20201101050334873.pdf) indicates that frequencies above 40MHz have unspecified accuracy, thus the marketing department was very optimistic on this feature.

The manual also says the maximum input voltage at that range is derated to 20VRMS maximum, although it says it has a 1000V overvoltage protection. How many volts did you apply?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 12, 2021, 03:01:53 am
On the video you nailed the interesting bits of the UT61 series: the lightning fast capacitance meter (the original UT61E is the king on this, even on capacitors with tens of thousands of µF) and its wide input frequency (which cooked the frequency range unfortunately). I did not improve the safety on mine since, as long as I keep it on the bench, I don't see it being cooked anytime soon. Also, the absence of an auto-power off is great.

Back to the frequency range, the UT61E+ manual (https://www.uni-trend.com/uploadfile/2020/1101/20201101050334873.pdf) indicates that frequencies above 40MHz have unspecified accuracy, thus the marketing department was very optimistic on this feature.

The manual also says the maximum input voltage at that range is derated to 20VRMS maximum, although it says it has a 1000V overvoltage protection. How many volts did you apply?


Right, they don't spec the voltage required for it to work above 40MHz, so I was creeping up on it.  I assume that 20V is the maximum required for it to read the proper value.   I searched for "derate" and it doesn't appear to be mentioned in the manual I have.  I certainly talks about the 1kV overload protection.     

I have no idea how much voltage I was putting into the meter.  There was nothing monitoring it.   I wonder what the impedance of the PTCs would be at 200MHz.   Consider most meters have a surge rated resistor in them, their impedance may be more inductive where the PTCs may be more capacitive.  I doubt the MOVs would have much of an effect as I had the low voltage clamps engaged.   Anyway, what I am getting at is the voltage may not be all that high but the impedance may be low causing excessive power to be dissipated in the PTCs.     

Easiest thing is not to put 200MHz on the box and I won't play at 200MHz.   But with it on the box I want to see it and I'll smoke the meter trying to get it there....   That should have been expected based on my previous years of videos..   :-DD

****

Plotting the impedance of a 1.5K surge rated resistor and a PTC.  These are not the parts used by the UT61E+ but they are parts I have shown and used in other meters.   You can see how the PTC is a lot less stable than the resistor.   I suspect this is one weakness in using two PTCs in series like the 61E+ in place of the more typical resistor+PTC combo. 

Again, the UT181A also uses the two series PTCs, but the manual shows the upper range is 60MHz.  In this case, we can verify this really is the upper limit.

https://youtu.be/PjNXbKlr3MI?t=1921 (https://youtu.be/PjNXbKlr3MI?t=1921)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 12, 2021, 03:33:28 am
The UNI-T UT61E+   

https://www.youtube.com/watch?v=4rADgFqFFH8 (https://www.youtube.com/watch?v=4rADgFqFFH8)

(Looks at length of video, very short)

Prediction: The grill starter killed it...  :popcorn:


Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 12, 2021, 03:41:13 am
Prediction: The grill starter killed it...  :popcorn:

Nope!  RF burns....
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 12, 2021, 02:18:59 pm
Looks like the majority would like to see it repaired and continue the testing.   Of course we will not use any of the data from these tests and it will purely be for entertainment.    The UNI-T fanboys can talk about how great the meter is if it survives or how I fucked it up during my repairs if it fails.   :-DD   


Fungus,
Good catch on the 17B+.  I am not sure why it was removed.  The one below it was also missing.   Guessing a user error.  I have added both meters back into the spreadsheet.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 12, 2021, 03:23:39 pm
I'm a bit confused: Shouldn't a hot PTC have saved the meter? Isn't that their job?
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 12, 2021, 04:06:50 pm
I'm a bit confused: Shouldn't a hot PTC have saved the meter? Isn't that their job?

It looks like they tried, but when dV/dt gets up to 1010V/s, things happen.  I'd be interested in knowing exactly how much power was applied to the meter.  Expecting a cheapo DMM to measure 220MHz on banana-jack inputs seems a bit outlandish, but that's what UNI-T puts on the box. They probably aren't expecting too many people to be able to actually give it 200MHz @ 20V.  I have a really nice frequency counter that only  goes to 180MHz on the high-impedance channel. 
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 12, 2021, 04:54:42 pm
I'm a bit confused: Shouldn't a hot PTC have saved the meter? Isn't that their job?

At those frequencies, he basically made a Metcal soldering iron from a meter.
All the RF energy was simply dissipated inside meter as heat..
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 12, 2021, 07:40:31 pm
I'm a bit confused: Shouldn't a hot PTC have saved the meter? Isn't that their job?

At those frequencies, he basically made a Metcal soldering iron from a meter.
All the RF energy was simply dissipated inside meter as heat..
Well, despite the PTC was cooked, the rest of the meter is intact (or should be).

Protection parts can be sacrifical parts.

That is a whole debacle over the role that CAT ratings have in cheaper meters that supposedly are approved (UT139C, UT61E for the EU market and so on): should they survive a transient unscathed or should they only guarantee the operator survives regardless of their own functional state? The second option should be expected, but the first one is a bit in the air.
Title: Re: Handheld meter robustness testing
Post by: bd139 on September 12, 2021, 08:00:51 pm
Personally if it blows the meter up and I survive then it’s a win. Meters can be replaced or possibly repaired.

Sometimes you can’t win.  people blow the meter up and then go for a second round…

And yes the fuse is soldered in as well.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 13, 2021, 12:59:00 am
I'm a bit confused: Shouldn't a hot PTC have saved the meter? Isn't that their job?

At those frequencies, he basically made a Metcal soldering iron from a meter.
All the RF energy was simply dissipated inside meter as heat..

OK, let's see if I've got this straight:
a) Very few actual electrons were getting through the PTC (it was hot!)
b) The PTC melted because of the capacitance of its own leg on the input side and the massive numbers of electrons rushing in/out heating up that leg.
c) The screen grayed out because of the huge EMP (https://en.wikipedia.org/wiki/Electromagnetic_pulse)s created inside the meter.

Well, despite the PTC was cooked, the rest of the meter is intact (or should be).

If my understanding above is correct then I'd agree.

PS: I think Evil Joe did this on purpose, knowing what would happen.

(...in which case he needs to do it to some more meters in the name of "fairness to Uni-T". How about one of the new Brymens, eg. the one that isn't calibrated? The dodgy Fluke 87V...? >:D )

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 13, 2021, 02:40:11 am
Part 2 is up. 

https://www.youtube.com/watch?v=XNRufJXNGIg (https://www.youtube.com/watch?v=XNRufJXNGIg)
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 13, 2021, 12:51:05 pm
That is a whole debacle over the role that CAT ratings have in cheaper meters that supposedly are approved (UT139C, UT61E for the EU market and so on): should they survive a transient unscathed or should they only guarantee the operator survives regardless of their own functional state? The second option should be expected, but the first one is a bit in the air.

The CAT ratings are safety standards, it just has to fail safe.
I don'y recall if that's for every test in the standard, but it's the basic gist of the high energy testing.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 13, 2021, 01:49:52 pm
That is a whole debacle over the role that CAT ratings have in cheaper meters that supposedly are approved (UT139C, UT61E for the EU market and so on): should they survive a transient unscathed or should they only guarantee the operator survives regardless of their own functional state? The second option should be expected, but the first one is a bit in the air.

AFAIK the CAT ratings have never even mentioned the first. All they say is that the device should fail safely.

Title: Re: Handheld meter robustness testing
Post by: Fungus on September 13, 2021, 01:59:09 pm
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1269721;image)
And yes the fuse is soldered in as well.

This is both:
a) Unbelievably common.
b) Why you never, ever borrow a meter in a life-or-death situation.

Still, it ought to take a major protocol failure for that 'fuse' to kill anybody. You shouldn't be holding the meter in your hand when you do any current measurements in an industrial environment - that's what magnetic holders are for - and you shouldn't be doing any current measurements at all where there's a danger of overload. Get a clamp, FFS

If I were an "Industrial Electrician" I wouldn't take a meter with any current measurement functions to work. I'd own a current clamp and the simplest possible multimeter, eg. a Fluke 113 (https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113) with only two input connectors and two positions on the dial.
Title: Re: Handheld meter robustness testing
Post by: bd139 on September 13, 2021, 04:23:01 pm
Makes sense to me. I rarely even use current measurement in electronics work. There’s usually a resistor somewhere I can take a voltage sample off or a calculation I can make. Breaking circuits for measurements is a pain in the ass.

When debugging some car issues recently I grabbed a cheap UT210E clamp meter.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 13, 2021, 11:34:24 pm
I've provided you with quotes from the standards and how at least one of the top handheld manufacture and one of the lower tier interprets them.   
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 13, 2021, 11:56:51 pm
The CAT ratings are safety standards, it just has to fail safe.
I don'y recall if that's for every test in the standard, but it's the basic gist of the high energy testing.

IIRC, the meter must continue to indicate the presence of hazardous voltages, although it doesn't have to be accurate.  This makes sense, or alternatively (not in the standards AFAIR, just my opinion) at least it should fail completely (no display) rather than indicate 0.000V.  Imagine I hang my meter up at a machine I want to test and hook it up, it says 240VAC.  I walk over to the service panel and turn off the wrong breaker, but there is a big transient that blows open the inputs on the meter--but doesn't cause any physical damage.  I come back and my meter reads 0VAC--so I go to work.  This is an argument against fused leads and also is the basis for the 'test before touch' protocol that requires that the meter be proved immediately before and after testing.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 13, 2021, 11:59:49 pm
And don't forget, there is actually a sticky thread for multimeters and safety which has nothing really to do with this thread. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 14, 2021, 01:30:09 am
I've provided you with quotes from the standards and how at least one of the top handheld manufacture and one of the lower tier interprets them.
Precisely. It hinges on interpretation. It is not crystal clear nor set in stone.

As I also mentioned before, this is understandable as standards are comprised of various players in the industry with different goals and aiming different target prices. There is always a give and take going on at standards' commitees.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 14, 2021, 02:26:36 am
I've provided you with quotes from the standards and how at least one of the top handheld manufacture and one of the lower tier interprets them.
Precisely. It hinges on interpretation. It is not crystal clear nor set in stone.

As I also mentioned before, this is understandable as standards are comprised of various players in the industry with different goals and aiming different target prices. There is always a give and take going on at standards' commitees.

IMO, besides the vague verbage I don't personally feel they have kept up with the times.  Who would ever have thought a meter with latching relays would every make it to market.  There's no test for it.   :-DD   Have they lost their way?   Seems so. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 14, 2021, 02:43:01 am
Who would ever have thought a meter with latching relays would every make it to market.  There's no test for it.   :-DD   Have they lost their way?   Seems so.

I'm not clear on the problem--there have been meters in the past that have used latching relays without issues that I know of.  Are you saying they are inherently problematic or that they aren't being used correctly?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 14, 2021, 03:46:14 am
The standards don't consider the kind of field given off from a magnetic hanger and why should they.   They have far more important things to consider, like their upcoming trips to Dubai.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 14, 2021, 09:31:36 am
Who would ever have thought a meter with latching relays would every make it to market.  There's no test for it.   :-DD   Have they lost their way?   Seems so.

I'm not clear on the problem--there have been meters in the past that have used latching relays without issues that I know of.  Are you saying they are inherently problematic or that they aren't being used correctly?
Being mechanical, relays are naturally more fragile than solid state parts for a handheld device (no issue with bench units), therefore there are chances of accelerated degradation or failure in an equipment used in a mechanically unstable environment - IIRC the standard does not have a mechanical test (although don't quote me on that). Unfortunately, I don't think there is data that shows drop tests on both types (solid state and relay) to quantify any degradation, either short or long term.

One additional problem that Joe has shown in top of the line meters (thus compliant) is that standards do not seem to be doing their part to account for magnetic susceptibility on their tests.

(Prior I had a brainfart moment and mentioned some silliness about the power consumption, to which Trader and HKJ corrected me).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 14, 2021, 02:18:13 pm
While large government bodies can be very costly and entertaining,  they are not always very responsive.  My view on these safety standards is more about trade and less about protecting the consumer.   The more shit I look at with approvals, the more diluted my view of them becomes.   

I like to ride motorcycles and proper safety gear is important.   We have DOT which is a large government agency but there is also the private, non-profit Snell certification. 

The following quotes are take from: https://smf.org/faq
 
Quote
William "Pete" Snell was the "Racer of the Year" when he died needlessly in a 1956 Sports Car Club of America racing event. His then state-of-the-art helmet, made of leather and pressed cardboard paper, didn’t protect him. The following year, in memory of Pete, a number of his friends, colleagues, and fellow racers, including Dr. George Snively, formed the Snell Memorial Foundation, now known as Snell Foundation. Its purpose was to set helmet performance standards to encourage the development and use of truly protective helmets.

Quote
DOT and ECE are law of the land for motorcycle helmets sold in the US and in European Union countries. Although government standards are required, they also are the minimal standards. Snell Standards demand the highest premium protection that current technology and materials can offer. Snell Standards are voluntary. Many of the best helmet manufacturers decide to design and make helmets to Snell Standards because many consumers seek out Snell certified helmets.

I only use Snell rated helmets.   

I don't frequently work in what I would consider a high risk electrical environment where equipment safety, PPE, training, kept me out of trouble or  I may be interested in seeing a similar independent safety group for my industry as well.   What I am interested in is finding meters that can survive some small transients without damage, unlike my first Fluke.  Because there really isn't much data on this and most reviews I saw were people opening boxes and blabbing,   here we are... 
Title: Re: Handheld meter robustness testing
Post by: nightfire on September 18, 2021, 01:48:19 pm
The CAT ratings are safety standards, it just has to fail safe.
I don'y recall if that's for every test in the standard, but it's the basic gist of the high energy testing.

IIRC, the meter must continue to indicate the presence of hazardous voltages, although it doesn't have to be accurate.  This makes sense, or alternatively (not in the standards AFAIR, just my opinion) at least it should fail completely (no display) rather than indicate 0.000V.  Imagine I hang my meter up at a machine I want to test and hook it up, it says 240VAC.  I walk over to the service panel and turn off the wrong breaker, but there is a big transient that blows open the inputs on the meter--but doesn't cause any physical damage.  I come back and my meter reads 0VAC--so I go to work.  This is an argument against fused leads and also is the basis for the 'test before touch' protocol that requires that the meter be proved immediately before and after testing.

In germany, safety regulations do also not allow to check for the absence of voltage with a DMM, you are to use a 2-pole voltage tester instead. (Well known brand here is "Duspol")
Reasons:
- Due to operator error, you could misplug the cables and end up in the low-impedance input of the DMM, which causes accidents
- due to the high impedance in todays multimeters, they can measure some "stray voltage" on the wires because of some capacitic effects on long cables. A 2-pole voltage tester has buttons where you can put a low impedance on that circuit so to see if the voltage remains or under load goes down
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 18, 2021, 02:09:39 pm
In germany, safety regulations do also not allow to check for the absence of voltage with a DMM, you are to use a 2-pole voltage tester instead. (Well known brand here is "Duspol")
Reasons:
- Due to operator error, you could misplug the cables and end up in the low-impedance input of the DMM, which causes accidents
- due to the high impedance in todays multimeters, they can measure some "stray voltage" on the wires because of some capacitic effects on long cables. A 2-pole voltage tester has buttons where you can put a low impedance on that circuit so to see if the voltage remains or under load goes down

Don't forget to take along a proving unit (https://www.google.com/search?q=Proving+Unit) to see if your fancy electronic gadget is working or not.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 18, 2021, 04:42:54 pm
In germany, safety regulations do also not allow to check for the absence of voltage with a DMM, you are to use a 2-pole voltage tester instead. (Well known brand here is "Duspol")
Reasons:
- Due to operator error, you could misplug the cables and end up in the low-impedance input of the DMM, which causes accidents
- due to the high impedance in todays multimeters, they can measure some "stray voltage" on the wires because of some capacitic effects on long cables. A 2-pole voltage tester has buttons where you can put a low impedance on that circuit so to see if the voltage remains or under load goes down

What would those regulations say about a DMM that doesn't have current ranges and is fully protected on the ranges that it does have (takes care of first problem) and has a Lo-Z function?
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 18, 2021, 05:16:45 pm
In germany, safety regulations do also not allow to check for the absence of voltage with a DMM, you are to use a 2-pole voltage tester instead. (Well known brand here is "Duspol")
Reasons:
- Due to operator error, you could misplug the cables and end up in the low-impedance input of the DMM, which causes accidents
- due to the high impedance in todays multimeters, they can measure some "stray voltage" on the wires because of some capacitic effects on long cables. A 2-pole voltage tester has buttons where you can put a low impedance on that circuit so to see if the voltage remains or under load goes down

What would those regulations say about a DMM that doesn't have current ranges and is fully protected on the ranges that it does have (takes care of first problem) and has a Lo-Z function?

When is a multimeter not a multimeter?

https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113 (https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113)

Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 18, 2021, 07:21:35 pm
In germany, safety regulations do also not allow to check for the absence of voltage with a DMM, you are to use a 2-pole voltage tester instead. (Well known brand here is "Duspol")
Reasons:
- Due to operator error, you could misplug the cables and end up in the low-impedance input of the DMM, which causes accidents
- due to the high impedance in todays multimeters, they can measure some "stray voltage" on the wires because of some capacitic effects on long cables. A 2-pole voltage tester has buttons where you can put a low impedance on that circuit so to see if the voltage remains or under load goes down

What would those regulations say about a DMM that doesn't have current ranges and is fully protected on the ranges that it does have (takes care of first problem) and has a Lo-Z function?

When is a multimeter not a multimeter?

https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113 (https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113)



Well that is exactly what I was explaining in that other topic. Bullet prof devices exist. They come with heavy limits.
If very limited functionality is sufficient for job at hand, they are perfect devices for the task.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 18, 2021, 11:23:10 pm
When is a multimeter not a multimeter?
https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113 (https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-113)

Well, it is still plenty 'multi' since it does VDC, VAC, (both with ranges down to 6.000V) Ohms, Capacitance, Diode and a bit of continuity.  But you don't have to go to that extreme either:

https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-116 (https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-116)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 18, 2021, 11:59:21 pm
https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-116 (https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-116)

That one's only CAT III 600V. The 113 is CAT IV 600V - Flukes highest rating!

If I'm an "electrician" I'm taking the 113.

(it's also much cheaper!  :) )
Title: Re: Handheld meter robustness testing
Post by: Per Hansson on September 19, 2021, 08:36:18 pm
Hey Joe thanks for your videos! Just watched your new video about the UT61E+ as it was recommended to me (see, you do get recommended by Youtube!) :)
I'm just curious if you would be willing to make a very simple input test: give the meter 230VAC on the ohms range.
That easily killed the old model, even when it was the "GS" typerated version with beefier input protection.
You can see my thread on it linked below, I managed to kill mine twice already this way :-DD
I do realize after you changed the input protection now it might fare better, but still an interesting test I'd say, as it is an easy mistake to do.
https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/msg3622382/#msg3622382 (https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/msg3622382/#msg3622382)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 19, 2021, 10:28:37 pm
Hey Joe thanks for your videos! Just watched your new video about the UT61E+ as it was recommended to me (see, you do get recommended by Youtube!) :)
I'm just curious if you would be willing to make a very simple input test: give the meter 230VAC on the ohms range.
That easily killed the old model, even when it was the "GS" typerated version with beefier input protection.
You can see my thread on it linked below, I managed to kill mine twice already this way :-DD
I do realize after you changed the input protection now it might fare better, but still an interesting test I'd say, as it is an easy mistake to do.
https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/msg3622382/#msg3622382 (https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/msg3622382/#msg3622382)
I read your previous posts.  One test I run is a taking a 220VAC, run it through bridge and apply that to the meter with it set to every mode.  Sadly, you will not find where I ran a UT61E beyond the one I modified for the purpose of surviving my tests.   The plan is to put the 61E+ through the normal tests but just not document any of the results due to it being slightly modified. 

I don't remember if Dave ran that test or not but it is something he has done in the past.  You could also check some of the unboxing videos.  Maybe someone has already done it with a virgin meter.     

****
Skimming Dave's review, he did not appear to run it this time for what ever reason.   
Title: Re: Handheld meter robustness testing
Post by: Per Hansson on September 20, 2021, 06:47:38 am
Thanks for your reply Joe, maybe Dave will see this thread and run the test on his.
I think it would be valuable, especially if it fails such an easy test as easily as mine does  >:D
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 20, 2021, 10:12:46 am
@Joe
Hi Joe, and first, keep safe and more importantly a big THANK YOU for keeping this thread going and your fascinating testing & analysis of dozens of DMMs over the last 6 years and counting!
I have read of course the rules that you set in your first post in this thread and I hope I am not disrespecting them if I have a request for you: would it be possible for you to test this unassuming, low cost (around $15 including shipping) UNI-T UT125C DMM? What makes it different from others in the same price range is that it is apparently independently certified to conform to UL STD 61010-1, -2-030, -2-033 and -031 and rated CAT III 600V.
It's a tiny thing, comparable in size to the Brymen BM27 which you have tested, only much thicker and mechanically sturdier. Now whether it would pass your gas grill lighter test is an unknown.
I am attaching two pics of the UT125C, a top view and an internal view which shows the PTCs and MOVs and protection diodes in its input path. Curiously there is also a spark gap but the component above it is not present, so I wonder if the spark gap has any use in this case.

Thanks again for your fascinating work!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 20, 2021, 12:14:24 pm
@Joe
Hi Joe, and first, keep safe and more importantly a big THANK YOU for keeping this thread going and your fascinating testing & analysis of dozens of DMMs over the last 6 years and counting!
I have read of course the rules that you set in your first post in this thread and I hope I am not disrespecting them if I have a request for you: would it be possible for you to test this unassuming, low cost (around $15 including shipping) UNI-T UT125C DMM? What makes it different from others in the same price range is that it is apparently independently certified to conform to UL STD 61010-1, -2-030, -2-033 and -031 and rated CAT III 600V.
It's a tiny thing, comparable in size to the Brymen BM27 which you have tested, only much thicker and mechanically sturdier. Now whether it would pass your gas grill lighter test is an unknown.
I am attaching two pics of the UT125C, a top view and an internal view which shows the PTCs and MOVs and protection diodes in its input path. Curiously there is also a spark gap but the component above it is not present, so I wonder if the spark gap has any use in this case.

Thanks again for your fascinating work!

There are a few problems I see running this meter.  First, its a brand known to fail.  13 products so far and all have performed poorly.  You're not seriously expecting a different outcome are you?   

Another problem I see is how the meter shares the inputs with the current function.  The problem there is depending how the meter is designed, the fuse may blow after each transient.   For two functions, that's  20 transients for each level, or 20 fuses.    I have seen meters like this before and point them out but have not ran them for this reason. 

Then there's what you are calling a spark gap.  It sure does look like that's the intent with the plated edges.  I would hope that gap is not directly across the inputs. If it is and has a UL safety cert, it would just further erode my confidence in these large bodies. 

Have you tried to find pictures of the bottom side?  You may be able to trace out the front end.

I have a UT90A that has a few spark gaps but I doubt very much these were by design.  They breakdown at such a low voltage, I could never permanently damage it.  Not doubt there are some idiots who would say that meter is very robust.    :-DD  After constructing the half cycle generator, I made another attempt to end it.     

https://www.youtube.com/watch?v=aRuI_q_K5RY (https://www.youtube.com/watch?v=aRuI_q_K5RY)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 20, 2021, 04:45:22 pm
I am attaching two pics of the UT125C, a top view and an internal view which shows the PTCs and MOVs and protection diodes in its input path. Curiously there is also a spark gap but the component above it is not present, so I wonder if the spark gap has any use in this case.
The thing I'm not seeing in the Uni-T is the big surge-rated resistor.

ie. I'd like to see one of these in the front end:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1277512;image)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 05:07:01 pm
I would hope that gap is not directly across the inputs. If it is and has a UL safety cert, it would just further erode my confidence in these large bodies.

That's a serious issue that some might be reluctant to discuss.  I recently had a UL-certified device (UV pool sanitizer) cause many thousands of dollars of damage and nearly burn my house down because it arced internally and started a fire.  It turns out the product had a known defect and was recalled, but I didn't know about that.  Now there are many ways in which a UL listing or label can be useless--it may be entirely faked, the product may not have been submitted for the testing one might expect, the exemplar submitted may not match the product as manufactured.....or other things even more disturbing.  In any case, my confidence in a testing lab label on its own, on a product from an unknown or not well reputed company, is not very high.

Quote
Not doubt there are some idiots who would say that meter is very robust.

Perhaps they haven't seen a Jacob's Ladder...
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 05:12:55 pm
The thing I'm not seeing in the Uni-T is the big surge-rated resistor.

Well, there's the fuse!

Now you tell me how the meter can meet the requirement to "continue to be able to detect and display the presence of hazardous voltages" or however it is phrased, if the fuse is blown?  Or is there some additional stuff on the other side of the circuit board?
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 20, 2021, 05:24:45 pm
Then there's what you are calling a spark gap.  It sure does look like that's the intent with the plated edges.  I would hope that gap is not directly across the inputs. If it is and has a UL safety cert, it would just further erode my confidence in these large bodies.

You mean this?

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1277563;image)

It sure looks like it's directly across the inputs, I think the metallic blob just above "F1" is where the black lead meets the PCB. Maybe AndrewBCN can confirm if it is or not.

Even if it is: The meter is only CAT III so there's supposed to be a circuit breaker between you and the big bad power cable in which case it could be "legal" to do that.

I'm not sure what the vertical white line between the two vias on side of that gap is. It looks like maybe a current shunt could be placed there in a different version of the meter.  :-//
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 20, 2021, 05:24:56 pm
Another problem I see is how the meter shares the inputs with the current function.  The problem there is depending how the meter is designed, the fuse may blow after each transient.   For two functions, that's  20 transients for each level, or 20 fuses.    I have seen meters like this before and point them out but have not ran them for this reason. 
IMO that is one of the worst features of any DMM. Sure, you can make the case that ultra-cheap meters cannot afford an extra input jack due to size/cost, but that is a terrible design decision for anything more serious that might be subjected to transients.

The thing I'm not seeing in the Uni-T is the big surge-rated resistor.
That tends to be replaced by R46, R47 and R48. 300kΩ each.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 20, 2021, 05:30:17 pm

Have you tried to find pictures of the bottom side?  You may be able to trace out the front end.


Yes, there are high resolution pictures of the top and bottom sides of the UT125C PCB on HKJ's website.

Top side: (https://lygte-info.dk/pic/UNI-T/UT125C/DSC_0904a.jpg)

Bottom side: (https://lygte-info.dk/pic/UNI-T/UT125C/DSC_0903a.jpg)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 20, 2021, 05:32:21 pm
The input is common to the PTCs and fuse.  The fuse goes back to the spark gap and onto the common point.  If the gap breaks over, the fuse may blow depending what I am dumping into it.  I could pull the fuse and test the two sets of functions but is that even a valid  test.   Then again, it's a UNI-T and the ESD would most likely stop the testing before we need to concern ourselves with a fuse.   In the end, is it really even worth spending any time looking at?   Don't we know how it will end? 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 20, 2021, 05:38:22 pm
While the UT61E+ uses a couple of PTCs in series to maybe double the breakdown voltage, here you have a single and nothing else to limit the current or reduce the voltage (in a controlled manor).  The 5mm parts can't handle much and I have shown many times the end result.   The outside case comes apart as it arcs over.  Once they arc, the MOVs may take the brunt of it.   But they are a long way away from the input...  Bases on all the tests I have ran on these low end meters, this just looks bad.   
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on September 20, 2021, 05:46:55 pm
If you think that Uni-T 135C is bad (and I agree with you), just be glad you haven't had the misfortune to encounter one of these turds:

https://www.amazon.co.uk/Kewtech-KT111-Automatic-Digital-Multimeter/dp/B01N1MPAHH (https://www.amazon.co.uk/Kewtech-KT111-Automatic-Digital-Multimeter/dp/B01N1MPAHH)
(https://m.media-amazon.com/images/I/61ALG42R8LL._SL1000_.jpg)

A colleague of mine who tests fire alarm systems and emergency lights in schools and local authority buildings was given one of these by his line manager. It would read 10VDC when measuring a 12V SLA battery, which while on charge should be around 13.5VDC. When he asked me to check it I was appalled at the gimcrack nature of the device from what is if not a premium manufacturer, at least a respected one.

Incidentally it was sent off for calibration, and apparently it was within spec...
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 20, 2021, 05:55:17 pm
If you think that Uni-T 135C is bad (and I agree with you), just be glad you haven't had the misfortune to encounter one of these turds:

"The ultimate electrician's digital Multimeter!"

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1277590;image)

Does "CAT III 500V" even exist as a rating?  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 06:01:44 pm
Yes, there are high resolution pictures of the top and bottom sides of the UT125C PCB on HKJ's website.

Can you pop the fuse out and confirm which end the positive lead is connected to?

Edit: it appears from one of HKJ's other photos that it is connected to the top (near the PTCs) as one would hope.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 20, 2021, 07:29:22 pm
That UNI-T UT125C looks like it was designed to guarantee arc flash accident if someone would connect it something with enough energy and there was a overvoltage event.....

It would arc over gap, evaporate copper trace, and draw arc towards cables that are mangled on the input in the case (insulation is badly damaged on cables on that photo..) All of that before fuse can blow.. Or it would arc over damaged cables first, distance might be even less than spark gap.
If that happens, arc would exit the case following the cables. Arc moves towards the source of the current (Jacob's ladder style).
All in all, pretty much death trap...


In attachment nice material from Stäubli. It is marketing material, but Germans being traditionally thorough, lots of good info. Also it shows perspective that cabling and accessories should be up to task too.  Very safe Fluke or Brymen means nothing if cables are mangled..

EDIT: Attachments are better if you actually attach them.  |O
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 20, 2021, 07:48:07 pm
If that happens, arc would exit the case following the cables.

It might.... if you used it outside the CAT III environment that it's rated for.

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 07:58:06 pm
It might.... if you used it outside the CAT III environment that it's rated for.

And where do you think CAT III is?  It's not your house.  AFAIK, a subpanel serving a 100HP 480VAC 3-phase motor with 200A breakers would (or could, depending on the exact setup) be CAT III.  CAT III definitely includes arc-flash hazards.  CAT II does not, IIRC.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 20, 2021, 08:40:24 pm
And where do you think CAT III is?

On the safest side of a distribution panel with circuit breakers in it.

We still don't know for sure if what we're looking at is a spark gap or where it is in the meter's input circuit, eg. Is it in series with the fuse?

To me it looks like there could be a current shunt across that gap in some variant of the mater (between the two vias where the vertical white line is painted).

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 08:48:34 pm
On the safest side of a distribution panel with circuit breakers in it.

I don't think that is how it is defined (a single-phase circuit on a 20A breaker can be CAT IV) and even if it generally works out that way, AFAIK there's no limit on the size of those breakers, or indeed any actual requirement that they exist--although electrical codes other than CAT would usually require them.

So here is a plausible example.  Suppose you have a large machine that uses 10 of these motors:

https://www.ebay.com/itm/352974263362?hash=item522ee7d442:g:BJoAAOSwdLJfS9qn (https://www.ebay.com/itm/352974263362?hash=item522ee7d442:g:BJoAAOSwdLJfS9qn)

And there is 575VAC 3PH service panel dedicated to this machine and it is located 100 feet from the main service entrance.  Inside the panel there is a main breaker feeding 10 individual breakers for each motor.

https://www.grainger.com/product/SQUARE-D-Molded-Case-Circuit-Breaker-6NHE7 (https://www.grainger.com/product/SQUARE-D-Molded-Case-Circuit-Breaker-6NHE7)

Note that the breaker will trip quickly (magnetically) at 12,000 amperes.  You hook up your UNI-T (I'll stick with the Fluke, thanks) meter to the output of one of the phases of the main breaker and there is a transient of 6000 volts.

That, AFAIK, is CAT III/600V.  Someone (not me!) should make that video. 

Quote
We still don't know for sure if what we're looking at is a spark gap or where it is in the meter's input circuit, eg. Is it in series with the fuse? To me it looks like there could be a current shunt across that gap in some variant of the mater (between the two vias where the vertical white line is painted).

It does appear to be a spark gap, at least in this version, and it is inline with the fuse, not directly across the inputs.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 20, 2021, 09:02:48 pm
If that happens, arc would exit the case following the cables.

It might.... if you used it outside the CAT III environment that it's rated for.

CAT III is already a serious place. It is circuit just after or on fuse panel. High fault currents are still possible.
For instance you have an 200kW elevator motor, that one would be CAT III because it is behind junction box and has a fuse.

A phase-to-phase fault on a 480-V system with 20,000 amperes of fault current provides 9600000 watts of power (9,6 MW). If the fault lasts for 200 milliseconds before the overcurrent protection clears it, the released energy would be 1,92 MJ, which corresponds roughly to a stick of dynamite.

At 20000A current, at a distance of 0.5 m, light intensity might reach magnitude of about 1,8 M lux! 

Fault currents in CAT III can be up to 25kA... I assure you that is a serious arc fault accident.

Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 20, 2021, 10:55:33 pm
Yes, there are high resolution pictures of the top and bottom sides of the UT125C PCB on HKJ's website.

Can you pop the fuse out and confirm which end the positive lead is connected to?

Edit: it appears from one of HKJ's other photos that it is connected to the top (near the PTCs) as one would hope.

Yes, the positive lead is connected to the side of the fuse that meets the PTCs. So I would guess if ever there is a transient that arcs across the gap, it should blow the fuse?
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 20, 2021, 10:59:15 pm
...
We still don't know for sure if what we're looking at is a spark gap or where it is in the meter's input circuit, eg. Is it in series with the fuse?
...

Yes, it is indeed a spark gap (the edges are plated) and yes, it is in series with the fuse.

... (insulation is badly damaged on cables on that photo..) ...

I had noticed that in HKJ's photo, and I checked mine: the insulation is not damaged in the unit I received.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 11:23:26 pm
Yes, the positive lead is connected to the side of the fuse that meets the PTCs. So I would guess if ever there is a transient that arcs across the gap, it should blow the fuse?

That's the idea, I'm sure.  As long as the fault current is less than the interrupt rating of the fuse, it should all work out.  If not there likely won't be enough left of the meter to determine who to sue.  Of course by using a spark gap instead of a sealed GDT, you've now ionized the interior of the meter, which may not be good in a dicey situation.  But UNI-T isn't alone in using intentional or unintentional spark gaps.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 20, 2021, 11:27:40 pm
...
So here is a plausible example.  Suppose you have a large machine that uses 10 of these motors:
...

...
A phase-to-phase fault on a 480-V system with 20,000 amperes of fault current provides 9600000 watts of power (9,6 MW).
...

Excluding the apocalyptic scenarios, we are talking about a $15 10cm tall DMM for home use, certainly not an electrician's tool for use in industrial settings. All I am interested in is that it is independently certified to a CAT III 600V rating. And of course I am curious about the spark gap. Btw if you look closely it also has a PCB cutout under the (beefy?) PTCs. So it seems that UNI-T spent a few extra cents to try to meet the CAT III rating, but was the effort and money well spent?
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 20, 2021, 11:28:27 pm
Yes, there are high resolution pictures of the top and bottom sides of the UT125C PCB on HKJ's website.

Can you pop the fuse out and confirm which end the positive lead is connected to?

Edit: it appears from one of HKJ's other photos that it is connected to the top (near the PTCs) as one would hope.

Yes, the positive lead is connected to the side of the fuse that meets the PTCs. So I would guess if ever there is a transient that arcs across the gap, it should blow the fuse?

It will blow the fuse, but they are slow devices. If current trough the fuse creates plasma near input terminals, it can resume taking current there, directly, and keep sustaining there, taking fuse out of the circuit.

In permanent installations, the only way to stop it is to cut power closer to the source, via protective switch that is designed for such fault current disconnections, otherwise it can arc over too... Unstopped, arc can travel hundreds of meters down the cables... It is a scary thing.

In this case, input cables would fail, and if there is a bit of luck they are connected to two sides far enough, it might extinguish when cables gap gets to big..

But all that is just talk.
People working on these kinds places where there is so much energy, should have proper tools, protective equipment and training in proper procedures and safety.

These meters are not what should be used in that case. No current range should exist on meter. Only noncontact current measurement....
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 20, 2021, 11:38:50 pm
...
So here is a plausible example.  Suppose you have a large machine that uses 10 of these motors:
...

...
A phase-to-phase fault on a 480-V system with 20,000 amperes of fault current provides 9600000 watts of power (9,6 MW).
...

Excluding the apocalyptic scenarios, we are talking about a $15 10cm tall DMM for home use, certainly not an electrician's tool for use in industrial settings. All I am interested in is that it is independently certified to a CAT III 600V rating. And of course I am curious about the spark gap. Btw if you look closely it also has a PCB cutout under the (beefy?) PTCs. So it seems that UNI-T spent a few extra cents to try to meet the CAT III rating, but was the effort and money well spent?

As I said, I would be reluctant to use it in CAT III environment.

And that apocalyptical scenario is requirement connected with CAT III.  Without it, it didn't pass... CAT III is industrial use category. Claiming it has CAT III makes it professional range meter..

And CAT II and CAT I you'll be fine with pretty much any meter. Sure it will be loud (or not so loud) bang. But you'll be safe. Inside house and in electronics lab, I agree with Joe: it bothers me more that you can damage those with static electricity. This is more likely to happen to you. Other apocalyptical scenarios can't happen inside your home. There is not enough energy. Except MOT.. those are nasty..

But a elevator technician can get in lot's of trouble in same building where your apartment is. 
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 20, 2021, 11:56:22 pm
...
Yes, the positive lead is connected to the side of the fuse that meets the PTCs. So I would guess if ever there is a transient that arcs across the gap, it should blow the fuse?
It will blow the fuse, but they are slow devices. ...

I believe there is a PTC+MOV in parallel with the spark gap + fuse across the input leads, shouldn't that react faster than the fuse?

So the transient energy would be absorbed in two steps, first by the PTC+MOV combo and then eventually second, by arcing across the spark gap and blowing the fuse?

I haven't measured the width of the spark gap but it seems to be about 1mm to 1.5mm wide, so the transient would need to be above 3kV to 4.5kV to arc across it, or am I getting it wrong?
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 20, 2021, 11:56:42 pm
All I am interested in is that it is independently certified to a CAT III 600V rating.

That is actually my concern as well, but from perhaps a different angle.  You really don't need CAT III around the house and and in most cases, there is not an actual arc-flash hazard anywhere in home wiring.  That's not to say you can't electrocute or burn yourself.  But people like the reassurance of having those labels because they see it as an accurate, impartial indication of quality and I don't think it is--this meter being pretty strong evidence of that.  So the casual user gets the reassurance of a (fake, IMO, certification or not) safety rating at a bargain price and the professional user knows to avoid them--so everyone's happy?  If that's good enough, then I guess that's just the modern world. 

The UNI-T is probably an OK $25 meter for hobby and household use, although the cable damage in HKJ's photo doesn't look good.  There's no way it should be wearing a CAT III/600V label, IMO, because that implies that it will withstand those 'apocalytic' scenarios.  How it got that label is what interests me, not whether or not it is a cheap piece of crap--as if that was a question.  And if it turns out that it got that CAT III/600V rating through entirely legitimate means, then the CAT ratings themselves are not a very strong indication of anything.  And that is bad for everyone, IMO.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 21, 2021, 12:06:26 am
...
Yes, the positive lead is connected to the side of the fuse that meets the PTCs. So I would guess if ever there is a transient that arcs across the gap, it should blow the fuse?
It will blow the fuse, but they are slow devices. ...

I believe there is a PTC+MOV in parallel with the spark gap + fuse across the input leads, shouldn't that react faster than the fuse?

So the transient energy would be absorbed in two steps, first by the PTC+MOV combo and then eventually second, by arcing across the spark gap and blowing the fuse?

I haven't measured the width of the spark gap but it seems to be about 1mm to 1.5mm wide, so the transient would need to be above 3kV to 4.5kV to arc across it, or am I getting it wrong?

With arc accidents, it is not transient that does damage. Transient creates plasma that creates short fault.
And power grid powers the explosion

Also in current measurements , PTC or MOV is not in a circuit. Only fuse and shunt...
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 21, 2021, 12:25:57 am
I believe there is a PTC+MOV in parallel with the spark gap + fuse across the input leads, shouldn't that react faster than the fuse?
I haven't measured the width of the spark gap but it seems to be about 1mm to 1.5mm wide, so the transient would need to be above 3kV to 4.5kV to arc across it, or am I getting it wrong?

Looks like 1 PTC +2 MOVs in series from the + lead to the large  (ground?) plane, but I don't see a direct connection to the - (COM) lead and in any case it is a pretty circuitous route. CAT III/600V test transients are 6kV/2 ohm, so 3000 amps?  That long, thin trace up the side of the board to the COB isn't going to be carrying that and the other route seems to go through the switch and 'stuff'. 

Yes, to jump the gap the transient would need to be ~3kV/mm on a dry day with no contamination of the inside of the meter. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 21, 2021, 02:58:00 am
Btw if you look closely it also has a PCB cutout under the (beefy?) PTCs.

 :-DD   As I stated, there's nothing there to save the PTCs except the PCB and leads.  Maybe the MOVs would open up first. 

Want to see what I consider a beefy PTC that can handle some shit?  Look at Fluke, Gossen, HIOKI.   See something else that's missing in your low end meter?   

...., but Germans being traditionally thorough, ....

I'm sorry that shield shown on the German designed Gossen looks like crap but hey, when they overlook such a basic problem there's not much else to do.  That's what you want, your customers solving your problems.   And when your distributors start spreading lies and corporate listens and propagate it without even asking the customer,  I don't consider that thorough.   That sounds like our news media.  I  see this as an even bigger problem giving us a glimpse into the culture.    I'm sure their engineers could have addressed the problems I found, but the best solution they could come up with was to change the name of the meter.  That's certainly being thorough. 

I feel sorry for the engineers that designed the electronics.  The basics are all there.  Move up the food chain, I'm not impressed. 


****

Those surge rated resistors are expensive.  Lets just put two 5mm PTCs in series.  What could go wrong?
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 21, 2021, 06:20:21 am
A phase-to-phase fault on a 480-V system with 20,000 amperes of fault current provides 9600000 watts of power (9,6 MW). If the fault lasts for 200 milliseconds before the overcurrent protection clears it, the released energy would be 1,92 MJ, which corresponds roughly to a stick of dynamite.

Sure, but would you even trust your CAT IV Fluke set to amps mode in that situation? I'd pay to watch you do it.  :popcorn:

My domestic 220V, 20A distribution panel is also CAT III. It seems a more likely scenario for somebody to use a $15 Uni-T there. I've had domestic short circuits before now and the walls of the house are still standing, not even any windows broken.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 21, 2021, 06:39:55 am
if it turns out that it got that CAT III/600V rating through entirely legitimate means, then the CAT ratings themselves are not a very strong indication of anything.  And that is bad for everyone, IMO.

CAT ratings have many grey areas. It's easy to invent worst-case scenarios for any category.

I'm not going to pretend to understand them but I'll happily point out that a CAT III 600V rating isn't automatically a CAT IV 300V rating even though they both say "6000V @ 2 Ohms" in the cute little chart.

ie. It's a lot more complicated than multiplying volts by amps.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 21, 2021, 06:46:58 am
With arc accidents, it is not transient that does damage. Transient creates plasma that creates short fault.
And power grid powers the explosion

Correct, but we have no idea how many volts are needed to jump the spark gap in this meter

(if it even is a spark gap - why would you have a spark gap in series with a fuse? To make sure the fuse blows faster?)
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 21, 2021, 08:07:02 am
...
 :-DD   As I stated, there's nothing there to save the PTCs except the PCB and leads.  Maybe the MOVs would open up first. 
...
Those surge rated resistors are expensive.  Lets just put two 5mm PTCs in series.  What could go wrong?

I think I understand: a surge rated resistor is needed in series with the PTC, to absorb part of the energy of the transient until the PTC has enough time to heat up and see its resistance value increase. If there is no surge rated resistor, the PTC absorbs all the energy of the transient before its resistance value has enough time to increase and could eventually fail catastrophically.

IIRC the CATIII 600V rating means the DUT has to withstand 10 repeated transients, so if the PTC fails catastrophically after the first or second transient, the DUT does not get the rating?
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 21, 2021, 08:54:06 am
IIRC the CATIII 600V rating means the DUT has to withstand 10 repeated transients, so if the PTC fails catastrophically after the first or second transient, the DUT does not get the rating?

The way I understand it is that the standards only say that the meter has to fail in a safe manner.

ie. the PTC can explode during the first transient and it still gets the rating if no shrapnel penetrates the case.


(Edit: For those who still don't get it... I sometimes exaggerate a tiny bit to get points across)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 21, 2021, 10:02:31 am
...
 :-DD   As I stated, there's nothing there to save the PTCs except the PCB and leads.  Maybe the MOVs would open up first. 
...
Those surge rated resistors are expensive.  Lets just put two 5mm PTCs in series.  What could go wrong?

I think I understand: a surge rated resistor is needed in series with the PTC, to absorb part of the energy of the transient until the PTC has enough time to heat up and see its resistance value increase. If there is no surge rated resistor, the PTC absorbs all the energy of the transient before its resistance value has enough time to increase and could eventually fail catastrophically.

IIRC the CATIII 600V rating means the DUT has to withstand 10 repeated transients, so if the PTC fails catastrophically after the first or second transient, the DUT does not get the rating?

It seems you feel that the transients I apply cause the PTCs to switch.   I have no idea why you would feel this way, but I've made whole videos on this subject.   You could also look at the datasheets for various PTCs and see what are the effects of various package sizes.

****
As far as the safety ratings, I have provided various quotes from the standards along with two large companies interpretations of them.  I've also tried to make it very clear that I am not an electrician and have little interest in the subject.  I've also tried to make it very clear that my transient tests have nothing to do with these standards.   I'm actually surprised how the majority of these threads become polluted with chatter on safety.  It wouldn't be too bad if you actually had people who worked in this industry chiming in.   

As far as what gets approval, hard to say.  Again, anymore I see the standards as outdated and more about trade than safety. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 21, 2021, 12:37:15 pm
CAT ratings have many grey areas. It's easy to invent worst-case scenarios for any category.

If it is going to wear the label, then it should be suitable for all the situations that the label covers, not just your home panel.

Quote
I'm not going to pretend to understand them but I'll happily point out that a CAT III 600V rating isn't automatically a CAT IV 300V rating even though they both say "6000V @ 2 Ohms" in the cute little chart.

I don't know whether that's true or not regarding the standards, even if certain manufacturers opt to not put a CAT IV label on where you might expect that they could.

Quote
The way I understand it is that the standards only say that the meter has to fail in a safe manner.

ie. the PTC can explode during the first transient and it still gets the rating if no shrapnel penetrates the case.

as discussed elsewhere:

"After the voltage of 4.4.2.101 has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.
NOTE The METER is not required to maintain its normal accuracy. A maximum deviation of 10 % is acceptable."
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 21, 2021, 01:36:07 pm
...
It seems you feel that the transients I apply cause the PTCs to switch.   I have no idea why you would feel this way, but I've made whole videos on this subject.   You could also look at the datasheets for various PTCs and see what are the effects of various package sizes.
...

I apologize for misunderstanding, Joe. It's just that what seems obvious to you, because you are so familiar with the subject, honestly flies way over my head most of the time.  :-[
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 21, 2021, 03:43:13 pm
as discussed elsewhere:

"After the voltage of 4.4.2.101 has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.
NOTE The METER is not required to maintain its normal accuracy. A maximum deviation of 10 % is acceptable."


I note you've missed out the next part of that text, which says:

Quote
"Conformity is checked by inspection while applying the maximum RATED voltage of each voltage measurement range capable of MAINS voltage measurements."

The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

Ref: https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/100/ (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/100/)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 21, 2021, 04:01:46 pm
as discussed elsewhere:

"After the voltage of 4.4.2.101 has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.
NOTE The METER is not required to maintain its normal accuracy. A maximum deviation of 10 % is acceptable."


I note you've missed out the next part of that text, which says:

Quote
"Conformity is checked by inspection while applying the maximum RATED voltage of each voltage measurement range capable of MAINS voltage measurements."

The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

Ref: https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/100/ (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/100/)

:-DD :-DD :-DD :-DD :-DD 

Fungus goes to school...

Title: Re: Handheld meter robustness testing
Post by: AVGresponding on September 21, 2021, 04:41:12 pm
as discussed elsewhere:

"After the voltage of 4.4.2.101 has been applied to the METER, the METER shall continue to be
able to indicate the presence of HAZARDOUS LIVE voltages up to the maximum RATED voltage.
NOTE The METER is not required to maintain its normal accuracy. A maximum deviation of 10 % is acceptable."


I note you've missed out the next part of that text, which says:

Quote
"Conformity is checked by inspection while applying the maximum RATED voltage of each voltage measurement range capable of MAINS voltage measurements."

The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

Ref: https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/100/ (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/100/)

But, aren't they prior to the range switch, and therefore part of the circuitry in play when in the volts ranges?
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 21, 2021, 04:53:20 pm
And where do you think CAT III is?

On the safest side of a distribution panel with circuit breakers in it.

So just to follow that up with a 'correction', or at least an acknowledgement that your statement has basis in fact, the very old UK 61010-2-033 that I got my hands on does indicate that CAT II is at least two breakers away from the transformer, CAT III a least one and CAT IV perhaps none.  No limit on size mentioned, available fault currents listed as 10kA, 50kA and >50kA respectively.  This is not the way I've seen is described in (much) later literature, but I don't have a later standard to look at. 

Edit: What I have also appears to just be addenda and revisions, and I'm lacking 61010-1 which they refer to extensively....so I really don't have much.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 21, 2021, 05:12:19 pm
I note you've missed out the next part of that text, which says:

Quote
"Conformity is checked by inspection while applying the maximum RATED voltage of each voltage measurement range capable of MAINS voltage measurements."

The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

No, I didn't miss that.  However, on the UNI-T we are trashing, one of the PTCs is in series with the voltage circuit and since there is no surge resistor, when the 2 MOVs clamp it will be roasted just as badly as if it were in series with another low-impedance circuit.  If that UNI-T can actually read mains voltage after being subject to 10 strokes of whatever transient most closely matches the CAT III/600V 6kV/2ohm IEC model, I'll buy one.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 21, 2021, 08:34:32 pm
...
If that UNI-T can actually read mains voltage after being subject to 10 strokes of whatever transient most closely matches the CAT III/600V 6kV/2ohm IEC model, I'll buy one.
Either you should set aside the equivalent to 15€ or you can lose all faith in independent certification companies. Because Intertek has indeed tested the UT125C. I found the UT125C in their directory, here:

https://ramuk.intertekconnect.com/WebClients/ITS/DLP/products.nsf/4c8700f3b75987a08525777700583333/1d393ddebcfb5489862586280014abff?OpenDocument
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 21, 2021, 09:28:10 pm
But, aren't they prior to the range switch, and therefore part of the circuitry in play when in the volts ranges?[/b]

He knows they are or I fear his cognitive functions are in decline.   Both very possible.  If the latter,  someone should take away his meters before he hurts himself.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 22, 2021, 01:13:12 am
The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

No, I didn't miss that.  However, on the UNI-T we are trashing, one of the PTCs is in series with the voltage circuit and since there is no surge resistor, when the 2 MOVs clamp it will be roasted just as badly as if it were in series with another low-impedance circuit.  If that UNI-T can actually read mains voltage after being subject to 10 strokes of whatever transient most closely matches the CAT III/600V 6kV/2ohm IEC model, I'll buy one.

I haven't looked closely at this particular Uni-T but generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 22, 2021, 01:54:55 am
Either you should set aside the equivalent to 15€ or you can lose all faith in independent certification companies. Because Intertek has indeed tested the UT125C. I found the UT125C in their directory, here:

I would happily spend the $22 to have my faith renewed in the certification process and gain a reliable meter that I don't need in the process.  Unfortunately I'm anticipating being disappointed by the Intertek Shenzen branch--or somebody, anyway.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 22, 2021, 02:07:17 am
I haven't looked closely at this particular Uni-T but generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

I'm not sure what you mean by the last part but in this case, have a look at the nice hi-res photos you'll see that once the input gets to 2X the knee voltage of those MOVs, the only finger in the dam other than the long, winding trace back to the COM lead is those PTCs--and they aren't in series.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 22, 2021, 02:11:16 am
The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

No, I didn't miss that.  However, on the UNI-T we are trashing, one of the PTCs is in series with the voltage circuit and since there is no surge resistor, when the 2 MOVs clamp it will be roasted just as badly as if it were in series with another low-impedance circuit.  If that UNI-T can actually read mains voltage after being subject to 10 strokes of whatever transient most closely matches the CAT III/600V 6kV/2ohm IEC model, I'll buy one.

I haven't looked closely at this particular Uni-T but generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

Keep those stories coming.  We're here all night folks. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 22, 2021, 06:32:23 am
Keep those stories coming.  We're here all night folks.

I'm having a moment, aren't I?
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 22, 2021, 09:48:43 am
Either you should set aside the equivalent to 15€ or you can lose all faith in independent certification companies. Because Intertek has indeed tested the UT125C. I found the UT125C in their directory, here:

I would happily spend the $22 to have my faith renewed in the certification process and gain a reliable meter that I don't need in the process.  Unfortunately I'm anticipating being disappointed by the Intertek Shenzen branch--or somebody, anyway.

You can anticipate whatever you want but facts are facts:

1. Intertek has certified the UNI-T UT125C.
2. Shenzhen (please note the correct spelling) is a modern, prosperous city of nearly 13 million, including thousands of permanently resident foreigners. https://en.wikipedia.org/wiki/Shenzhen (https://en.wikipedia.org/wiki/Shenzhen)
3. Intertek has countless offices in China, 13 of which are located in Shenzhen. https://www.intertek.com/contact/asiapacific/china/ (https://www.intertek.com/contact/asiapacific/china/)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 22, 2021, 11:47:50 am
Keep those stories coming.  We're here all night folks.

I'm having a moment, aren't I?

I suspect you have been looking at too many low end meters like the UNI-T,  ANENG....    Your statement about "...generally multimeters have a separate 10MOhm voltage input.." could be correct as I suspect there are more low end meters being introduced and sold.    We love our cheap, disposable products which drives the market and I just don't want to admit it. 

***
You won't see me posting anytime soon about how electrically robust (or mechanically) Dave's 121GW meter is but it's input circuit uses the more common approach I find in the meters that do well against my tests.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 22, 2021, 12:10:51 pm
I suspect you have been looking at too many low end meters like the UNI-T,  ANENG....    Your statement about "...generally multimeters have a separate 10MOhm voltage input.." could be correct

Yeah, the only ones I've sat and traced out (a couple of years ago) were cheapies and the voltage input went straight to the 10MOhm resistor chain with a separate branch where the 10K resistor and (single) PTC was.

I've just watched this again and I'm all edumacated now:

https://www.youtube.com/watch?v=zUhnGp5vh60 (https://www.youtube.com/watch?v=zUhnGp5vh60)

The meter in that video^ (Fluke 27) has two input branches, one with only a resistor before it goes off to the ADC.  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 22, 2021, 12:31:52 pm
I suspect you have been looking at too many low end meters like the UNI-T,  ANENG....    Your statement about "...generally multimeters have a separate 10MOhm voltage input.." could be correct

Yeah, the only ones I've sat and traced out (a couple of years ago) were cheapies and the voltage input went straight to the 10MOhm resistor chain with a separate branch where the 10K resistor and (single) PTC was.

I've just watched this again and I'm all edumacated now:
...

The meter in that video^ (Fluke 27) also has two input branches, one with just a resistor before it goes off to the ADC.  :popcorn:

On the UT61e I had attached, you have that 1k connected directly to the input.   The other side to a 10M.  The 10M has various capacitors which gives the meter a very wide AC response.   Of course, there's a downside to it.

Dave's 121GW uses a couple of PTCs in series to act as a load for AC mains testing.  There's nothing else to limit it.   The funny thing with this meter is the mechanical switch does not have enough clearance and it will arc over the contacts at a fairly low voltage.  It's been certified by Intertek so it must be safe. 


https://www.youtube.com/watch?v=wYCGnYglRjY (https://www.youtube.com/watch?v=wYCGnYglRjY)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 22, 2021, 02:00:56 pm
The meter in that video^ (Fluke 27) has two input branches, one with only a resistor before it goes off to the ADC.  :popcorn:

I've never looked at the 27.  No doubt Fluke has changed their secret sauce over the years.  Their front end designs have certainly evolved since my first DMM, the 8000A.   Even the Fluke 77 I looked at was an improvement over my first meter but it can't come close to the level of robustness seen with their later generations.  I think I ran that old, abused Fluke 189 up to 6kV without any problems.  They have certainly gained my respect. 

And if we want to talk about the mechanical robustness, to this day, I have not seen a switch that handled that life cycle test like the Fluke 17B+.  Looking at how the 87V was cutting into the PCB and how it was chattering, I  think they have learned a few tricks there as well.

****
This is the sort of thing general customers don't see or consider.  This kind of innovation that improves reliability and reduces downtime is one reason why Fluke is where they are today.

****
It's easy enough for you to verify what you are watching on YT.  See the attached service manual.   

https://www.testmart.com/webdata/mfr_pdfs/FLU/27______smeng0100.pdf (https://www.testmart.com/webdata/mfr_pdfs/FLU/27______smeng0100.pdf)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 22, 2021, 07:18:57 pm
3. Intertek has countless offices in China, 13 of which are located in Shenzhen. https://www.intertek.com/contact/asiapacific/china/ (https://www.intertek.com/contact/asiapacific/china/)

They may have a lot of offices, but I'm sure they can keep count.  It wouldn't speak well for their organizational skills otherwise.  How is this relevant to the issue at hand?

Quote
2. Shenzhen (please note the correct spelling) is a modern, prosperous city of nearly 13 million, including thousands of permanently resident foreigners.

I think the Chinese spell it " 深 圳 " but there may not be agreement on that either.  AFAIK, there is no 'correct' spelling otherwise as it is just an attempt at phonetical representation of sounds that don't easily match up to any English pronunciations.  Don't know about French.  These representations seem to change over the years in some attempt to more correctly represent how they are pronounced by the Chinese.  So "Mao Tse Tung" is now "Mao Zaedong" and perhaps someday the current leader "Xi" will become "Sjhee" or something.  I haven't heard enough native Chinese speakers pronounce the name of the city to have an opinion on which representation is best, but apparently "Shenzhen" is the most popular at the moment.  How is this relevant to the issue at hand?

Quote
1. Intertek has certified the UNI-T UT125C.

And Moody's certified sub-prime mortgage bonds as AAA before they weren't.  Nobody was prosecuted and Moody's still collects huge fees to rate bonds, even they they obviously were grossly negligent, IMO inherently corrupt, and very, very wrong.  The result in either case here--AAA bond rating or CAT III/600V certification--appears to be that you end up with a worthless turd with a pedigree.  We just haven't seen the UT125C blow up yet.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 23, 2021, 03:42:06 am
CAT III is already a serious place. It is circuit just after or on fuse panel. High fault currents are still possible.
For instance you have an 200kW elevator motor, that one would be CAT III because it is behind junction box and has a fuse.

A phase-to-phase fault on a 480-V system with 20,000 amperes of fault current provides 9600000 watts of power (9,6 MW). If the fault lasts for 200 milliseconds before the overcurrent protection clears it, the released energy would be 1,92 MJ, which corresponds roughly to a stick of dynamite.

At 20000A current, at a distance of 0.5 m, light intensity might reach magnitude of about 1,8 M lux! 

Fault currents in CAT III can be up to 25kA... I assure you that is a serious arc fault accident.

Article on arc flash testing.
https://www.ecmag.com/section/safety/lets-blow-it-arc-flash-testing (https://www.ecmag.com/section/safety/lets-blow-it-arc-flash-testing)

Quote
The Mersen lab has two generators. Each generator is rated 10 megavolt-amperes (MVA) continuous with a short-circuit rating of 68 MVA and is powered by a 4,160-volt (V), 536-horsepower electric motor that is directly connected to the utility. When a test is conducted, the short-circuit current comes from the generator and not the electric utility.


This lab has the capability to produce up to 100,000A of short-circuit current at 480V.


What I refer to as my half cycle simulator hardly compares with the tests they conduct.   With the low energy levels I use, there is enough evidence left over to determine what went wrong.  Still a small amount of copper can create a fairly impressive pressure wave.
 
https://www.youtube.com/watch?v=xLDok9Sm07Q (https://www.youtube.com/watch?v=xLDok9Sm07Q)

https://www.youtube.com/watch?v=ivZ7F7u10W4 (https://www.youtube.com/watch?v=ivZ7F7u10W4)

https://www.youtube.com/watch?v=ms5OIBnQ_ig (https://www.youtube.com/watch?v=ms5OIBnQ_ig)

Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 23, 2021, 10:56:32 am
...
How is this relevant to the issue at hand?
...

The fact that Intertek has certified the UNI-T UT125C is certainly relevant to the issue at hand. But the baseless or irrelevant dribble you posted certainly isn't.

Apart from your "anticipating being disappointed by the Intertek Shenzen (sic) branch", do you have anything to say based on facts relevant to the issue at hand?
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 23, 2021, 12:03:24 pm
Apart from your "anticipating being disappointed by the Intertek Shenzen (sic) branch", do you have anything to say based on facts relevant to the issue at hand?

I dunno about your Uni-T but there's a bunch of Aneng meters that are "certified" (with downloadable certification certificates!) but one look a the PCB will tell you it's lie.

eg. The Aneng Q10 (https://www.aliexpress.com/item/1005001447667137.html).

Download your CAT III 600V / Cat II 1000V certificates here: https://zotektools.com/products/zty/ (https://zotektools.com/products/zty/)
 
(yes, Anengs are manufactured by Zotek)

See photos of the PCB here: https://www.eevblog.com/forum/testgear/aneng-goes-crazy-with-new-meters/msg3338126/#msg3338126 (https://www.eevblog.com/forum/testgear/aneng-goes-crazy-with-new-meters/msg3338126/#msg3338126)

Joe: If I'm reading it right this is a meter where the input goes directly from the volts jack to the IC with only R16 and R17 in between. The PTC is on a separate circuit (after going through the range switch!)

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1279897;image)

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1279903;image)

At least they used MELFs!  :-+

Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 23, 2021, 12:37:18 pm
...
Yep. There's a bunch of Aneng meters that are "certified" with downloadable certification certificates but one look a the PCB will tell you it's lie.
...

1. "one look at the PCB" is not enough for much. If it were, we would all be experts at everything. Ah, but I forgot: you are an (self-proclaimed) expert...  :-DD
2. What exactly do you claim is a lie? The certificate (hence the lier would be Zotek) or that the meter was indeed tested and passed the tests (hence the lier would be the certification company, in this case Anbotek)? You yourself wrote just three days ago that such claims require clear evidence, but I don't think you have any evidence whatsoever to backup your claim.
3. How is the Zotek ZT-Y certification by Anbotek relevant to the UNI-T UT125C certification by Intertek? We are talking about two different products from two different companies certified by another two different companies. Where is the similarity here?

You and bdunham7 are welcome to purchase, disassemble and test the UNI-T UT125C for robustness or standards compliance anytime you see fit and report your results here or in another thread, but until then, perhaps refrain from the baseless claims and "anticipating being disappointed" sort of comments a little bit?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 23, 2021, 12:54:56 pm
Free meters!!!  It's been a while since anyone has "reached out" to me with such an offer. 

I have no intention on turning my channel into a marketing tool.   

If UNI-T or Gossen "reached out" about updates that address what we saw with their products, I would certainly invest the time to look at them a second time.   If Brymen came out with a meter that would out class the BM869s, I would certainly be interested in having a look.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 23, 2021, 01:01:58 pm
.... If it were, we would all be experts at everything.  ...

We are! 

https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols (https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols)


Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 23, 2021, 01:53:22 pm
.... If it were, we would all be experts at everything.  ...

We are! 

https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols (https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols)

Very interesting article. So most of us are "armchair experts" (putting it kindly) and you know that!  >:D

On the other hand Joe, you have put > 6 years of effort into building your knowledge of "DMM robustness" as you modestly put it, have disassembled, destroyed and rebuilt countless DMMs, have designed and built your own test equipment, and have read and understood countless datasheets for components that are used in DMMs.

I had a friend who used to repair PC power supplies for a living, a dozen or more a day, and after years of the same routine he could usually diagnose the problem in less than 30 seconds (he had a PSU test rig which he had built himself), confirm his diagnosis with a $10 multimeter and unsolder the faulty components and resolder new ones in less than 5 minutes tops. I am not sure that made him an expert in PSU design or reliability, but on the other hand he never made any such claims. He spoke little and always worked in silence, actually.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 23, 2021, 02:02:26 pm
1. "one look at the PCB" is not enough for much. If it were, we would all be experts at everything. Ah, but I forgot: you are an (self-proclaimed) expert...  :-DD

I think I'm at the point now where I can follow a PCB trace.  :)

I also know that a genuine CAT rating includes all combinations of input jacks and switch positions and that Aneng fuses aren't 1000V rated.

You can actually see in that photo where it says 250V on both the fuse and the PCB:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1279954;image)

2. What exactly do you claim is a lie?

See above^.

CAT II 1000V, CAT III 600V rated? Somebody's pants are on fire.

Is Uni-T/Intertek more reputable for $15? I'm not an expert but even I can see the lack of a surge-rated resistor.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 23, 2021, 02:08:23 pm
We are! 

https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols (https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols)

There certainly are a frightening variety of mindsets out there and I'm often disturbed--but not longer surprised--by what 'normal' people are willing to believe at times.  However, I don't think any discussion of this issue is complete without the issue of experts losing their credibility due to them being wrong--overstating their knowledge, lying for various reasons and so on.  People may lack the basic education to even comprehend a subject that affects them--whether it is medical, electrical or financial--but if they become convinced, rightly or wrongly, that their experts have lied to them, what else do they have to go on?

 

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 23, 2021, 02:26:34 pm
Joe: If I'm reading it right this is a meter where the input goes directly from the volts jack to the IC with only R16 and R17 in between. The PTC is on a separate circuit (after going through the range switch!)

That appears correct and it's not uncommon.   

Running a meter like yours against my tests, the PTC would break down.  When that happens, they present a low impedance path to the low voltage clamp, which then opens up.  After this, the next device in the chain is the IC.   The only thing left to do after that is toss it. 

Yours may survive my ESD tests where the UT61E would not.   One difference between the UT61E and this meter is there's no high frequency compensation on the meter yours.     

An unhappy radio hobbyist.... excuse me... expert,  "reached out" to me about damaging the UT61E+.   I suspect the whole idea that the PTCs were capacitive at higher frequencies was totally lost on them.   Odd when you think their hobby is based on RF.   Then again, my wife uses her cell phone to also advance the art, with no understanding of how it works.  :-DD 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 23, 2021, 03:31:14 pm
The fact that Intertek has certified the UNI-T UT125C is certainly relevant to the issue at hand. But the baseless or irrelevant dribble you posted certainly isn't.

Apart from your "anticipating being disappointed by the Intertek Shenzen (sic) branch", do you have anything to say based on facts relevant to the issue at hand?

Since you seem fascinated with English grammar and so forth, the typical word used in such a phrase is 'drivel' not 'dribble'.  I may in fact occasionally 'drivel', but I am neither so young or so old that I 'dribble' much.

Facts?  Multimeter input protection is not a new game and has been implemented, studied and improved for years.  The design, layout and components required to achieve certain levels of input protection are well known.  When lo-buck meter X arrives claiming a certain level of performance but obviously lacks components typically used in other similar products or uses components and designs that have been repeatedly shown to fail in other products, you are left to choose between believing either that Meter X company has ingeniously innovated by leveraging unique, newly differentiated synergies among select components to achieve unprecedented levels of excellence--or that they are full of shit.
Oh, and there's a pile of dead meters from Meter X companies previous attempts.

Quote
1. "one look at the PCB" is not enough for much. If it were, we would all be experts at everything. Ah, but I forgot: you are an (self-proclaimed) expert...

As long as there is a ruler or some method of determining scale in the picture--even a known SMD component will do--and you have a calibrated Mark VII eyeball, you can certainly spot creepage and clearance insufficiencies.  You can also follow circuit traces and get some idea of the input circuitry layout.  Admittedly, the UT125C appears to have more protection components and effort than I would have expected in a $16 device--at least they aren't so insulting as to have nothing at all and then claim that it has 'triode' protection (SMD transistor), as one other manufacturer did while back.  I'm still willing to bet $16 against it's survival.

I wish I had more facts.  I wish I had the complete standard used to look at to see what I might be missing.  I'm aware that I don't have the whole picture.  But that doesn't stop me or anyone from thinking about it.

Quote
perhaps refrain from the baseless claims and "anticipating being disappointed" sort of comments a little bit?

Sir, this is EEVBlog.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 23, 2021, 03:34:38 pm
Free meters!!!  It's been a while since anyone has "reached out" to me with such an offer. 

I'm torn. You could accept it and zap it.

Was it Dave or you that did a bad 'review' of something and the manufacturer put it on their web page anyway? I don't remember.  :-DD

(Bad meter! Bad!)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 23, 2021, 05:59:34 pm
Quote
... you can certainly spot creepage and clearance insufficiencies.

Some of those last pictures looked tight.  They are all certified so I am sure they are fine to use in their rated environment.   


Free meters!!!  It's been a while since anyone has "reached out" to me with such an offer. 

I'm torn. You could accept it and zap it.

Was it Dave or you that did a bad 'review' of something and the manufacturer put it on their web page anyway? I don't remember.  :-DD

(Bad meter! Bad!)

It may have been one of Dave's.  My reviews are too boring to be use as an advertisement.   

HIOKI also "reached out" to me a while ago.   I use some of their equipment for industrial work.  I don't believe they are certified.  :scared:
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 25, 2021, 12:28:43 am
Hioki and Sanwa are self-certified. Judging by the many decades on the market with good quality products (and still produce them), I think it is safe to say they are alright for the most part.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 25, 2021, 04:20:39 am
HIOKI also "reached out" to me a while ago.   I use some of their equipment for industrial work.  I don't believe they are certified.  :scared:

That's common for the Japanese meters, they do self certification to the standard.
[/quote]

I stand corrected.
I forgot that Sanwa do independent testing by SGS.
Not sure if that's for all meters, but if they go to the trouble for their pocket meter then I'd assume they do it for the bigger meters too.


Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 25, 2021, 08:21:53 am
HIOKI also "reached out" to me a while ago.   I use some of their equipment for industrial work.  I don't believe they are certified.  :scared:

That's common for the Japanese meters, they do self certification to the standard.
But as opposed to the Chinse companies, the Japanese actually do do it and take it seriously.
And to be clear, you're suggesting that ALL of the Chinese do not? 

***
As long as we are making broad statements, I'm curious to know your opinion which is safer, a Chinese product certified by Intertek or a self certified Japanese product? 
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 25, 2021, 08:08:17 pm
HIOKI also "reached out" to me a while ago.   I use some of their equipment for industrial work.  I don't believe they are certified.  :scared:

That's common for the Japanese meters, they do self certification to the standard.
But as opposed to the Chinse companies, the Japanese actually do do it and take it seriously.

I'm not sure about that - I'd emailed Sanwa and Hioki asking for Certificate of Conformance or any proof about their multimeter 61010 claims.
One response was "Safety design in compliance with the IEC61010-1".  We all know "designed to" means only good intentions or "faith" an engineer has...

There are many ways to cheat and circumvent safety approvals, so I say real players can provide the cert or file number with an agency.
ANENG 61010 certificate is just for a 3V battery-powered device, no hazardous energy connected to it. chinese reports can be very hokey, skipping many tests.
Uni-T got real 61010 TUV for Germany but depopulated the MOV's for sales anywhere else. So I think they suck in terms of ethics and thankfully their meters are shit for robustness as they save $0.08 there.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 12:18:58 am
That's common for the Japanese meters, they do self certification to the standard.
I'm not sure about that - I'd emailed Sanwa and Hioki asking for Certificate of Conformance or any proof about their multimeter 61010 claims.

The post you quoted literally says they don't do that, they only do internal conformance testing.

ANENG 61010 certificate is just for a 3V battery-powered device, no hazardous energy connected to it. chinese reports can be very hokey, skipping many tests.

Then you say you don't believe in certificates anyway.  :-//

PS: Yes, Aneng meters are 3V battery powered.

Title: Re: Handheld meter robustness testing
Post by: floobydust on September 26, 2021, 01:09:07 am
Claim your product complies with 61010, then back it up with the report and CofC. No need for secrecy.

If you have done independent 61010 compliance testing, it still can be by a hokey regulatory agency and misled into doing partial tests, i.e. as a 3V device. The "Cat. III 600V" claims are of course nothing but fake markings.

It's either no certificate, or a fudged certificate.

One product I delved into had electrical safety compliance done by Quality Assurance International (QAI). (https://qai.org/listing-directory/electrical-products-directory/) The largest organic food certifier. What could possibly go wrong lol.

"Internal conformance testing" just what is this exactly? The Honour System.
You can't self-declare compliance with safety standards, any more than Boeing lol.
Companies can't afford all the test equipment such as Transient generator, decoupling network, when it will be used just a handful of times a year. The calibration costs alone (50lbs shipping) are high. So it ends up cheaper to get UL/CSA etc. to do the tests in their labs.
CE-marking maybe worked long ago but china has exploited the fact nobody checks for compliance, and we allow fake or no safety approval products to enter the country.

Engineers can design to their heart's content and think it's all good- but testing is done to prove the PC board spacings are adequate, components etc. work and it stays reasonably safe.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 06:05:37 am
I guess when I posted that the 15€ UNI-T UT125C was certified by Intertek this sparked (hehe) a debate in this thread about the worth of independent certification.

Some here question the value of independent certification. The problem with this sentiment, if it becomes widespread, is that manufacturers of electronic test equipment will be tempted to entirely skip the certification process, since their marketing dept will just declare that it is a useless cost that is irrelevant to consumers and won't affect sales. In other words, this will discourage manufacturers from getting their products independently certified.

People here should realize that most consumers do not take apart their DMMs, etc when they get them to check the internals, they just use them as is. And almost all of us are totally incapable of judging the safety or robustness or standards compliance of a DMM, even when we have it taken apart in front of our eyes. And of course AFAIK only Joe has any real test equipment setup to actually test DMMs for their robustness. The rest of us are "armchair experts" i.e. total idiots, even if some believe otherwise.

Imo independent testing and certification is a valuable step in bringing a DMM or any piece of test equipment to market, and every DMM review should clearly state whether the device reviewed has been independently tested and certified or not, to what standards, and by which independent certification company. Whether this will actually encourage manufacturers to get their products certified is another question, but it would be a step, however small, in the right direction.

The blanket statement that independent certification is "worthless" is, imo, a step in the wrong direction. Also, any certificate can be "fudged", that applies to just about anything, from DMMs to diesel engines to jets. The question is whether it is worth it to "fudge" the certificate and risk being exposed. Personally I'll never buy another VW car or fly in a 737-MAX, but that's just me and it seems I am a rather rare case.

Just as a disclaimer, I am not connected to any independent certification company, my opinions are my own, etc.

Edit: Apparently some people here believe that the number of YouTube videos about a specific piece of test equipment is a better indicator of the safety standards compliance than an independent certification. This is actually quite a common phenomenon in modern marketing, where bloggers and vbloggers have become just another promotional tool - and the reason why Joe periodically gets called out by manufacturers to review their equipment, even though he makes clear that his channel was not created with that purpose.
 
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 06:19:56 am
Engineers can design to their heart's content and think it's all good- but testing is done to prove the PC board spacings are adequate, components etc. work and it stays reasonably safe.

You think Fluke engineers just design, cross their fingers, and send meters out to third party testers?

No, they have a room full of meter zapping equipment and test it themselves at every stage during development. Find the weak points and eliminate them. Third party testing only happens after the meter is fully production-ready.

Hioki just skips the last step.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 06:27:51 am
...
No, they have a room full of meter zapping equipment and test it themselves at every stage during development. Find the weak points and eliminate them. Third party testing only happens after the meter is fully production-ready.
Hioki just skips the last step.
You don't actually know that for sure, do you?  Unless you have worked with any DMM manufacturer development team at any point in your life, which I am certain you didn't...

Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 06:55:32 am
...
No, they have a room full of meter zapping equipment and test it themselves at every stage during development. Find the weak points and eliminate them. Third party testing only happens after the meter is fully production-ready.
Hioki just skips the last step.
You don't actually know that for sure, do you?  Unless you have worked with any DMM manufacturer development team at any point in your life, which I am certain you didn't...

And you don't know for sure that they don't.

I choose to believe it because:
a) Hioki are reputable in the same way that Fluke/Brymen/Amprobe are reputable.
b) They don't sell meters for $25 on Aliexpress
c) I've seen Hioki Teardowns
d) Joe's zapped some Hiokis
e) Dave says Hioki do the internal testing

and finally...

f) Because it's not an unreasonable assertion. You seem to be demanding extraordinary evidence (https://en.wikipedia.org/wiki/Sagan_standard) for something that doesn't really require it.

Yes, I know Joe has revealed some flaws in "serious" meters like Gossens but they weren't failures to meet basic CAT standards.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on September 26, 2021, 07:51:31 am

"Internal conformance testing" just what is this exactly? The Honour System.


"The Honor System." works if you have honor.

As it is now, I have much more trust in honor of a good Japanese company, than in USA safety certification agencies..

But that is just feelings.

Facts are, I know many companies that do internal testing, and do it well. Some products are hard to make compliant, and any precompliance must be done in full blown in house compliance lab during course of design. Once you have full lab, you might as well use it. They go independent party only if mandated. And since nobody wants liability and competition would  gladly crucify them, they do not only good job but make sure there is healthy reserve if possible...
Fluke does exactly that, and so do many others. OTOH, FLUKE does a lot of work with industries that have mandates for specific testing, so they go outside for those..

A good question would be: is there any verified information how many industrial accidents were caused by using UNI-T meters..?
A research, by numbers, how much more accidents happen by using UNI-T than Fluke?
I would like to see that information..

I still have UNI-T UT71C somewhere.  Worst part is that it worked very good as a electronics meter at desk, it was accurate up to specs for years, had very fast peak detect mode, and centered bar-graph mode, very accurate AC mV/V measurements with better than 100kHz bandwidth,  high Z mV DC mode, etc. etc..
It never got damaged. I didn't try to give it "Joe treatment" though, but in a controlled lab environment (with basic static control) it survived.
What was wrong with it was mechanically really cheap. Input jacks are some leftover pieces of sheet metal that look like someone bent them by hand, inserted into inner part of plastic socket. That makes it that thin plastic inner tube is holding all the inserted banana forces and they break in no time (and it wasn't fancy glass filled good plastic, but some cheap plastic). Meter was few months old when it started cracking. I had to find some thin brass tubes and remade those sockets, inserting tubes into plastic and fixing it with epoxy.  It was solid since.

It is like Joe said for UT181: it had all the potential to be great meter, they did many things right and then screwed up on   a bit of PCB layout, one resistor (mine is EU version with MOVs and big fuses), plating on a switch and better input sockets..
And for crying out loud, on UT181, use standard  Li-ion cells (like 18650 or whatnot), that can be replaced by user so you can also charge them outside..

Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 08:22:17 am
...
A good question would be: is there any verified information how many industrial accidents were caused by using UNI-T meters..?
A research, by numbers, how much more accidents happen by using UNI-T than Fluke?
I would like to see that information..
...

In your dreams. Please be realistic, who would pay for such information to be researched and published, and in any case, how would you guarantee that the information wouldn't be "fudged"?

This is exactly why we have mandated safety standards and independent testing and certification companies. And it is also exactly why we, as consumers, should prefer products that are independently tested and certified vs. products that are not.

Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 08:45:59 am
...
I choose to believe it because:
a) Hioki are reputable in the same way that Fluke/Brymen/Amprobe are reputable.
b) They don't sell meters for $25 on Aliexpress
c) I've seen Hioki Teardowns
d) Joe's zapped some Hiokis
e) Dave says Hioki do the internal testing
...

 :-DD Thanks for a good laugh! c) above is absolutely priceless! d) and e) are good too.

From a), b), c), d) and e) I would assume that you don't own a Hioki DMM, and possibly have never laid your hands on one either. Note that neither do I, but I am not claiming anything about Hioki DMMs or the Hioki brand.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on September 26, 2021, 09:03:33 am
...
A good question would be: is there any verified information how many industrial accidents were caused by using UNI-T meters..?
A research, by numbers, how much more accidents happen by using UNI-T than Fluke?
I would like to see that information..
...

In your dreams. Please be realistic, who would pay for such information to be researched and published, and in any case, how would you guarantee that the information wouldn't be "fudged"?

This is exactly why we have mandated safety standards and independent testing and certification companies. And it is also exactly why we, as consumers, should prefer products that are independently tested and certified vs. products that are not.

Here in the UK the HSE collects such data, and the ONS will analyse it. I expect there are similar agencies in France and elsewhere around the world.

I'd be quite surprised to see anyone injured at work by using a Uni-T meter instead of a Fluke, as no serious electrician, electrical or electronics engineer that I have ever met would choose to use one in that setting.

I'm not a Uni-T hater either; I have a UT 139C and I like it. It's good at what it does. I would never use it at work, or for working with any high energy circuit at home, I have various Flukes, Agilents, Keithleys etc etc for that.

Information being "fudged" is exactly why independent testing isn't the panacea you seem to think it is. There are far too many examples of cheap meters with various test houses' marks on them that simply don't match up with those implied standards under closer scrutiny.
There may be several reasons for how and why this happens; one well known and well discussed route is to change the internal design post certification.

It doesn't get caught by national agencies responsible for checking these things because they just don't have the personnel or resources. Think about some of the plug-top usb chargers we've all seen videos of from the likes of Big Clive, utterly lethal in some not too improbable circumstances, and certainly the number of people thusly exposed will be higher than the number of hobbyists at risk from dodgy 61010 certs on cheap meters, and yet these things still make it into the hands and homes of consumers.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 09:26:32 am
:-DD Thanks for a good laugh! c) above is absolutely priceless!

Feel free to point out any safety issues:

https://www.youtube.com/watch?v=D8Rom9Owsyo (https://www.youtube.com/watch?v=D8Rom9Owsyo)

https://www.youtube.com/watch?v=ZCQCmhr5AYQ (https://www.youtube.com/watch?v=ZCQCmhr5AYQ)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 26, 2021, 04:01:23 pm
Feel free to point out any safety issues:
The batteries are a choking hazard and the supplied leads use probes that are very sharp.  They have fuses that can easily be jumped  out.  I also suspect they use materials known by the state of CA to cause cancer.   
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 04:20:17 pm
...
Feel free to point out any safety issues:
( links to two YouTube videos )

...
which is safer, a Chinese product certified by Intertek or a self certified Japanese product? 

Which is safer, a self-certified 200€ Japanese CAT IV 600V DMM that is the subject of two YouTube videos, or a 15€ Chinese CAT III 600V "YouTube-less" DMM certified by Intertek?

Which tastes better, a $20 orange with ten YouTube videos or a $1.50 apple with no YouTube videos?






Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 04:32:02 pm
Which is safer, a self-certified 200€ Japanese CAT IV 600V DMM that is the subject of two YouTube videos

Joe's video clearly says "Part 1 of 3" in the title, so that's at least four videos.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 26, 2021, 04:33:44 pm
Which is safer, a self-certified 200€ Japanese CAT IV 600V DMM that is the subject of two YouTube videos

Joe's video clearly says "Part 1 of 3" in the title, so that's at least four videos.

I tend to be long winded and do a little more than open the box and give them five stars. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 26, 2021, 04:53:37 pm
A good question would be: is there any verified information how many industrial accidents were caused by using UNI-T meters..?
A research, by numbers, how much more accidents happen by using UNI-T than Fluke?
I would like to see that information..

The problems with that is are 1) there probably aren't very many of these accidents, not like auto accidents anyway  2) arc-flash and other accidents are probably more likely to be caused by issues other than a failure of the meter, like dropping or mishandling, mishandling the probes or working on circuits beyond the low voltage range, and 3) if you just looked at what type of meter was being used during such an incident it is much more likely to be Fluke because nobody (at least that I know, here in the US) is going to be out working on sawmill motor during a thunderstorm with any meter by UNI-T.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 05:17:31 pm
Which is safer, a self-certified 200€ Japanese CAT IV 600V DMM that is the subject of two YouTube videos

Joe's video clearly says "Part 1 of 3" in the title, so that's at least four videos.

Awesome!  :-DD
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 26, 2021, 05:24:33 pm
People here should realize that most consumers do not take apart their DMMs, etc when they get them to check the internals, they just use them as is. And almost all of us are totally incapable of judging the safety or robustness or standards compliance of a DMM, even when we have it taken apart in front of our eyes.

Well apparently if you buy UNI-T you better take it apart to make sure they haven't omitted parts in production that were needed to get their 'certification'.  And no, we aren't "totally incapable" of observing that one product uses carefully matched isolation slots and internal shielding, has larger PTCs, uses higher interrupt rated fuses, observes published creepage and clearance requirements, etc etc--and another product doesn't do all that.  Of course it is true that we generally don't have any concrete means of correlating those features to actual performance on a particular test, but as a relative comparison tool I don't see the problem.  I don't buy the notion that consumers should make their choices solely or even primarily on the results if this sort of testing or 'level' of certification--even if the results aren't fake. 

Quote
Imo independent testing and certification is a valuable step in bringing a DMM or any piece of test equipment to market, and every DMM review should clearly state whether the device reviewed has been independently tested and certified or not, to what standards, and by which independent certification company. Whether this will actually encourage manufacturers to get their products certified is another question, but it would be a step, however small, in the right direction.

The blanket statement that independent certification is "worthless" is, imo, a step in the wrong direction. Also, any certificate can be "fudged", that applies to just about anything, from DMMs to diesel engines to jets. The question is whether it is worth it to "fudge" the certificate and risk being exposed. Personally I'll never buy another VW car or fly in a 737-MAX, but that's just me and it seems I am a rather rare case.

You seem to be defeating your own argument.  Those examples you gave were exactly what happens when a company concentrates on meeting getting past the test for this or that standard instead of devoting their efforts to building a good product. 

Title: Re: Handheld meter robustness testing
Post by: floobydust on September 26, 2021, 05:52:45 pm
Feel free to point out any safety issues:
joeqsmith says his content and this thread is not about safety, it's about robustness.

The follow-through current is zero. It's mains transient testing minus the mains. So a GDT looks wonderful, when it's actually not.
Kreosan had some fun with their transient testing which included mains, might be worth figuring out.
edit: spelling
https://www.youtube.com/watch?v=9M_OX-O9JKk (https://www.youtube.com/watch?v=9M_OX-O9JKk)
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 06:01:03 pm
...
Well apparently if you buy UNI-T you better take it apart to make sure they haven't omitted parts in production that were needed to get their 'certification'.  And no, we aren't "totally incapable" of observing that one product uses carefully matched isolation slots and internal shielding, has larger PTCs, uses higher interrupt rated fuses, observes published creepage and clearance requirements, etc etc--and another product doesn't do all that.  Of course it is true that we generally don't have any concrete means of correlating those features to actual performance on a particular test, but as a relative comparison tool I don't see the problem.  I don't buy the notion that consumers should make their choices solely or even primarily on the results if this sort of testing or 'level' of certification--even if the results aren't fake.

Well that is your opinion which you are naturally entitled to, and it seems it is based on how you compare your own expertise vs that of entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs. Which brings us back to the article that Joe linked to.

Good for you, you and others here are all experts. And probably because I am such an idiot, I prefer to rely on independent certification processes.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 06:21:03 pm
Kreosan had some fun with their transient testing which included mains, might be worth figuring out.

I'm not old enough to watch that. Apparently.

(How old would I have to be? Methuselah age?)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 06:29:13 pm
And no, we aren't "totally incapable" of observing that one product uses carefully matched isolation slots and internal shielding, has larger PTCs, uses higher interrupt rated fuses, observes published creepage and clearance requirements, etc etc--and another product doesn't do all that.

Well that is your opinion which you are naturally entitled to, and it seems it is based on how you compare your own expertise vs that of entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs.

You don't have to be an expert to see that stuff is in there.

I don't imagine Hioki puts Those components in there randomly, hoping for the best.

PS: Don't forget the guard traces: I can see those, too. I don't think even Fluke does those.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1282771;image)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 26, 2021, 06:31:29 pm
jeoeqsmith says his content and this thread is not about safety, it's about robustness.

The follow-through current is zero. It's mains transient testing minus the mains. So a GDT looks wonderful, when it's actually not.
Kreosan had some fun with their transient testing which included mains, might be worth figuring out.

If we're saying that it isn't about 'safety' as in industrial arc-flash accidents, then I'd agree, these evaluations aren't conclusive.  But IMO, 'safety' and 'robustness' can't be separated that easily.  As your video shows, you don't need a high-fault current CATIII/IV environment to blow something up and potentially be injured, although you likely won't be vaporized.  And I consider it paramount that the meter continue to work, whether that is considered a safety issue or not.  IOW, I don't think that a meter that is not 'robust' can be considered 'safe'. 

As for MOV vs GDT, obviously the issue with a GDT (other than speed) is that it clamps to a low voltage once activated, which means something else has to absorb the energy and the voltage need to cease momentarily for conduction to stop.  The MOV will stop conducting when the voltage goes below the knee.  I don't know anything about that GDT design in the Hioki, but I have to wonder what happens if you are measuring 1000VDC in a HVDC solar system (a CAT III  environment apparently) and you get a transient large enough to arc the GDT.  I hope that either the PTC is up to the task or those input resistors are fairly high values so that the current at 1000VDC--once the transient ends--is low enough that the GDT stops conducting.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 26, 2021, 06:43:12 pm
jeoeqsmith says his content and this thread is not about safety, it's about robustness.

The follow-through current is zero. It's mains transient testing minus the mains. So a GDT looks wonderful, when it's actually not.
Kreosan had some fun with their transient testing which included mains, might be worth figuring out.

Your first sentence is true but the bolded statement is not accurate.  I use the open circuit voltage waveform but with 2X the FWHH.   The short circuited current is limited to about 20J max.  Even with no AC lines, the transients I apply are no where near the energy of what the actual IEC surge standards call for.  Again, that was never a goal.  While I can continue to correct these statements for another four years, there are going to be those who never understand it.   Their expert opinions will continue to fuel the confusion.  Those average Americans anyway... Oh wait...  :-DD :-DD
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 26, 2021, 06:48:49 pm
jeoeqsmith says his content and this thread is not about safety, it's about robustness.

True, but joe's little sparks indicate the presence of ignition sources in arc flash situations.

Joe doesn't evaluate what would happen next if there was a ton of energy available behind that spark but any meter that sparks internally at a given test voltage should be on the "probably unsafe" list.

PS: Even Joe's little sparks can make meters jump around inside the testing box and that alone could be enough to make you fall off a ladder in fright if the meter was in your hand.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 26, 2021, 07:00:34 pm
how you compare your own expertise vs that of entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs.

No, you just don't get it.  I don't compare or equate my expertise or observations with "entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs", in fact I like working on and repairing equipment designed by such people because I can admire and learn from their efforts.  However, I don't confuse high-quality products made by such companies with rubbish hacked together on a shoestring by third rate hacks.  There are many impediments to producing a high-quality product, and when there is intense pressure to meet cost control and time objectives, quality standards become minimal requirements that just have to barely be met--if that.  My distrust of these low-buck purveyors of proven unreliability is not based on technical expertise, but rather first-hand experience of how corporations and their management function. 

Quote
I am such an idiot, I prefer to rely on independent certification processes.

You just cited examples of companies you would avoid because of egregious failures of their independently (to a point) certified products.  I just had a UL certified product cause a fire due to piss-poor construction of a connector.  If you accept a single certification test of a product from company at the bottom of the market (with a history of failures in the jqs test and questionable ethics regarding omitting parts) as positive proof that it will provide sufficient protection to the user in an extremely harsh, dangerous environment, well that is idiotic.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 26, 2021, 08:03:23 pm
how you compare your own expertise vs that of entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs.
...
I don't compare or equate my expertise or observations with "entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs", in fact I like working on and repairing equipment designed by such people because I can admire and learn from their efforts.
...
You misunderstood. The teams I was referring to are the testing teams at certification companies, who you seem to believe don't exist or don't matter. As to comparing yourself to the teams that develop testing equipment at any of the major manufacturers, well... I'll leave you to your delusions of grandeur.  :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 26, 2021, 08:06:34 pm
...
If we're saying that it isn't about 'safety' as in industrial arc-flash accidents, then I'd agree, these evaluations aren't conclusive. 
...

Again, I want to be very clear that the IEC surge has nothing to do with arc-flash.  And while I based my open circuit voltage waveform on the IEC surge open circuit waveform, that's about all they have in common.  Comparing anything I show to a surge test shows a total lack of understanding.   Thinking it has anything to do with arc flash testing is a whole new level.     

Over the years I have heard of three arc flash events from people I know.   Two of them resulted in death where a procedure was not followed.  It had nothing to do with the equipment.   The investigation in the third case revealed a faulty meter (nothing like what I am reviewing).  In that case no one was injured thanks to PPE. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 26, 2021, 09:03:03 pm
You misunderstood. The teams I was referring to are the testing teams at certification companies, who you seem to believe don't exist or don't matter.

OK.  Do you mean 'teams' like the team at the UL that certified the piece of junk that nearly burned my house down or the team at the FAA that certified the Boeing 737 MAX?  Are you really going to have blind faith in some 'team' that you know nothing about in a 'laboratory' that you know nothing about?  Do you have any actual knowledge about the lab or the process other than spelling the name of the city they are in?  This reminds me a lot of the discussions elsewhere about calibration laboratories. 

Quote
As to comparing yourself to the teams that develop testing equipment at any of the major manufacturers, well... I'll leave you to your delusions of grandeur.  :-DD

Either you misread what I actually said or you actually think UNI-T is a 'major manufacturer', a term which to me implies an A-brand, not a mass marketer of copycat cut-rate rubbish.  You seem intent on ridiculing my statements even if you have to misquote or misconstrue them to do so.  Are you still sore about the "fanboy apologist fantasy" wisecrack?  8)
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 26, 2021, 09:49:30 pm
jeoeqsmith says his content and this thread is not about safety, it's about robustness.

The follow-through current is zero. It's mains transient testing minus the mains. So a GDT looks wonderful, when it's actually not.
Kreosan had some fun with their transient testing which included mains, might be worth figuring out.

Your first sentence is true but the bolded statement is not accurate.  I use the open circuit voltage waveform but with 2X the FWHH.   The short circuited current is limited to about 20J max.  Even with no AC lines, the transients I apply are no where near the energy of what the actual IEC surge standards call for.  Again, that was never a goal.  While I can continue to correct these statements for another four years, there are going to be those who never understand it.   Their expert opinions will continue to fuel the confusion.  Those average Americans anyway... Oh wait...  :-DD :-DD

Is your goal theoretical robustness or real-world, or theatrical robustness lol. I think even us non-Americans can appreciate the differences.

Mains transients are superimposed on the sine-wave, so any crowbar (i.e. GDT) action will last for a long time, not mere usec but msec. Typically 1/2 cycle to zero-cross but much worse when there is copper vapor and soot to clear. Cat. III can have high fault currents for the long duration which is the safety issue I am trying to point out, but you seem to be missing.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 26, 2021, 10:07:52 pm
Again, I want to be very clear that the IEC surge has nothing to do with arc-flash.  And while I based my open circuit voltage waveform on the IEC surge open circuit waveform, that's about all they have in common.  Comparing anything I show to a surge test shows a total lack of understanding.   Thinking it has anything to do with arc flash testing is a whole new level.

I'm not sure 'nothing to do with' is a fair assessment.  One possible path to a catastrophic arc flash incident starts with a meter breaking down under something resembling the IEC surge test.  You don't need to have an arc flash to have an injury incident or a fire, but in the wrong time and place, an arc flash is one possible result.  As both you and I have said now within the past few posts, there are a lot of other ways to start an arc flash as well. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 26, 2021, 11:14:12 pm
Is your goal theoretical robustness or real-world, or theatrical robustness lol. I think even us non-Americans can appreciate the differences.

Mains transients are superimposed on the sine-wave, so any crowbar (i.e. GDT) action will last for a long time, not mere usec but msec. Typically 1/2 cycle to zero-cross but much worse when there is copper vapor and soot to clear. Cat. III can have high fault currents for the long duration which is the safety issue I am trying to point out, but you seem to be missing.

My goal was to run various meters against a common standard to determine which were more electrically robust.  Obviously the IEC standards are superimposed on the line.  Again that has nothing to do with what I have been showing for the last several years beyond basing my open circuit voltage waveform on the surge.   I have had a few people ask me about testing AC line devices which point to just how ignorant some viewers are.  I don't see that changing although I run into it less and less.       

Again, I want to be very clear that the IEC surge has nothing to do with arc-flash.  And while I based my open circuit voltage waveform on the IEC surge open circuit waveform, that's about all they have in common.  Comparing anything I show to a surge test shows a total lack of understanding.   Thinking it has anything to do with arc flash testing is a whole new level.

I'm not sure 'nothing to do with' is a fair assessment. 
...

Is that your expert opinion based on your interpretation of what several others have posted about their own interpretations of the standards,  which I doubt they ever actually read?    It seems par for the internet.  :-DD
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 27, 2021, 12:38:05 am
HIOKI also "reached out" to me a while ago.   I use some of their equipment for industrial work.  I don't believe they are certified.  :scared:

That's common for the Japanese meters, they do self certification to the standard.
But as opposed to the Chinse companies, the Japanese actually do do it and take it seriously.
And to be clear, you're suggesting that ALL of the Chinese do not? 

Of course not.
Uni-T offer some models that are independently tested, but they also offer many other models that are crap.
The vast majority of chinese meters are not certified, you know that.

Quote
As long as we are making broad statements, I'm curious to know your opinion which is safer, a Chinese product certified by Intertek or a self certified Japanese product?

I'm not playing your game, sorry.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 27, 2021, 12:52:44 am
HIOKI also "reached out" to me a while ago.   I use some of their equipment for industrial work.  I don't believe they are certified.  :scared:
That's common for the Japanese meters, they do self certification to the standard.
[/quote]

I stand corrected.
I forgot that Sanwa do independent testing by SGS.
Not sure if that's for all meters, but if they go to the trouble for their pocket meter then I'd assume they do it for the bigger meters too.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 01:09:37 am
Quote
As long as we are making broad statements, I'm curious to know your opinion which is safer, a Chinese product certified by Intertek or a self certified Japanese product?
I'm not playing your game, sorry.
There's no way I would touch that one but I thought you may take a swing at it.  :-DD

***
As long as I am thinking about it, a member had asked about connecting the UT61E+ to the 220V mains with it set to the resistance mode.   I had checked your review and you did not run that test.  Because I had already damaged the one I bought, any way to talk you into running it with yours?   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 02:12:21 am
Part 3, the damaged/repaired/slightly modified UNI-T UT61E+ meets the gas grill starter and other implements of destruction.   

https://www.youtube.com/watch?v=gzBl7Pd0dCM (https://www.youtube.com/watch?v=gzBl7Pd0dCM)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 27, 2021, 04:28:29 am
No, you just don't get it.  I don't compare or equate my expertise or observations with "entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs", in fact I like working on and repairing equipment designed by such people because I can admire and learn from their efforts. However, I don't confuse high-quality products made by such companies with rubbish hacked together on a shoestring by third rate hacks.

Do you learn nothing from people who are asked to make a full size multimeter at a $25 price point?

If anything, it's more difficult then working on a massive budget to make a "high quality" meter.

Quote
As long as we are making broad statements, I'm curious to know your opinion which is safer, a Chinese product certified by Intertek or a self certified Japanese product?
I'm not playing your game, sorry.
There's no way I would touch that one but I thought you may take a swing at it.  :-DD

Yep. Anbody that frames this as "China vs. Japan" instead of "Uni-T vs. Hioki" is at the Donald Trump level of debate.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 27, 2021, 04:39:53 am
As long as I am thinking about it, a member had asked about connecting the UT61E+ to the 220V mains with it set to the resistance mode.   I had checked your review and you did not run that test.  Because I had already damaged the one I bought, any way to talk you into running it with yours?

Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 27, 2021, 04:51:15 am
No, you just don't get it.  I don't compare or equate my expertise or observations with "entire teams of electronics engineers that do testing day in, day out with special-purpose equipment in dedicated labs", in fact I like working on and repairing equipment designed by such people because I can admire and learn from their efforts. However, I don't confuse high-quality products made by such companies with rubbish hacked together on a shoestring by third rate hacks.

Do you learn nothing from people who are asked to make a full size multimeter at a $25 price point?

If anything, it's more difficult then working on a massive budget to make a "high quality" meter.

Quote
As long as we are making broad statements, I'm curious to know your opinion which is safer, a Chinese product certified by Intertek or a self certified Japanese product?
I'm not playing your game, sorry.
There's no way I would touch that one but I thought you may take a swing at it.  :-DD

Yep. Anbody that frames this as "China vs. Japan" instead of "Uni-T vs. Hioki" is at the Donald Trump level of debate.

Problem is the vast majority of cheap meters come out of China, that's just a fact. Literally hundreds of different models all built down to a price.
Is there any "no name" cheap meter manufacturer in Japan? I'd assume there would have to be, but off-hand I can't remember seeing one. Sanwa, Hioki and Kyoritsu are the only names that spring to mind, and all are reputable makers of top tier pricing industrial meters.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 27, 2021, 05:06:29 am
Do you learn nothing from people who are asked to make a full size multimeter at a $25 price point?

If anything, it's more difficult then working on a massive budget to make a "high quality" meter.

It is true that ingenuity can often be found in simplicity, but I rarely find it as appealing when it involves cost-cutting beyond a certain point.  Shortcuts get taken and stuff gets left out.  I've dealt with cost-cutting in many situations (not multimeters) and in my experience the people looking to achieve that goal make it difficult for everyone else more than they do for themselves.   So yes, I learn nothing from them because even if they know something, it's not knowledge that I want or need anymore than I need to learn how to make a stew from a roadkill possum and a pair of old shoes.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 10:44:27 am
As long as I am thinking about it, a member had asked about connecting the UT61E+ to the 220V mains with it set to the resistance mode.   I had checked your review and you did not run that test.  Because I had already damaged the one I bought, any way to talk you into running it with yours?

Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.

Thanks.  I tried running mine 300VACRMS 60Hz and it also survived.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 11:01:45 am
When I was a child I had some small toys that came from Japan.  We would call them gypan as the toys would fall apart after a short use.   I would imagine that Tachikawa meter I looked at was very cheap for the time.   Even today, I'm not impressed with the display used on the YOKOGAWA TY720. 
Title: Re: Handheld meter robustness testing
Post by: Muttley Snickers on September 27, 2021, 11:35:49 am
This morning I accidentally destroyed a multimeter which had served me well for over twenty five years so I'm not happy about it and feel like I've lost a dear friend.   :-BROKE :(

I couldn't get the lawn mower started and after checking everything else I found the throttle controlled kill switch had an intermittent short to the chassis which explained why the mower would run for a few seconds and then cut out.

The meter copped a whack from the magneto whilst in resistance mode and is now completely buggered. Out of curiosity I repeated the same scenario with a Fluke 83 without any problems. The damaged meter was a Dick Smith Q1425 and has a 40 pin ICL7106CPL dated 10/94 so almost 27 years old but in immaculate condition for its age.

Edit: Image to follow soon. 
Title: Re: Handheld meter robustness testing
Post by: Muttley Snickers on September 27, 2021, 12:04:40 pm
It wasn't anything special meter wise and they are a dime a dozen nowadays, back then they were around $20. Also, there are already enough threads and information around on these and similar meters so I didn't feel it warranted a new thread.

Title: Re: Handheld meter robustness testing
Post by: Kean on September 27, 2021, 12:14:51 pm
The damaged meter was a Dick Smith Q1425 and has a 40 pin ICL7106CPL dated 10/94 so almost 27 years old but in immaculate condition for its age.

Another 10 years or so and it would probably have been manufactured in Japan.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 27, 2021, 01:04:21 pm
As long as I am thinking about it, a member had asked about connecting the UT61E+ to the 220V mains with it set to the resistance mode.   I had checked your review and you did not run that test.  Because I had already damaged the one I bought, any way to talk you into running it with yours?

Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.

Thanks.  I tried running mine 300VACRMS 60Hz and it also survived.   
I evaluated several meters on my channel and, although I don't apply an untamed outlet-level power supply on them, I use a reduced 80~90V current-limited source to get an idea of a meter's survivability in case of wrong selection by a user - a much more common case of multimeter failure (when compared to transients) among the folks that watch my channel. Even at that ridiculously low level, several meters failed this specific test with weird behaviour such as resetting, powering down, beeping uncontrollably, etc., giving a hint about its survivability.

In my anecdoctal evidence of comments and reports from the audience and direct messaging to me, the UL listed UT139C is the meter that died the most, despite passing my test. It is a very weak sample space which can be easily skewed by popularity and availability, since a Brazilian brand has a fully certified UT139C as well as others that I also tested (which failure rate reporting is nowhere near as bad), but that and my experience with certification and compliance (non-multimeter though) tell me the process is flawed and must be improved. And that is where the cynicism comes from us that touched many of these types of equipment: too many examples of flaws that look like have been solely relied (or heavily influenced) on the cert agency accreditation mark to guide design decisions.

Is it a third party independent testing a better scenario than self-certification or reputation alone? Yes, of course, especially since most people don't understand the technicalities of what they are buying - unfortunately this hasn't been he ideal scenario as time and time again it has been proven it is caveat emptor. That is why youtube and the internet have been acting as a "fourth party" source of information.
Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 27, 2021, 01:06:00 pm
.... If it were, we would all be experts at everything.  ...

We are! 

https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols (https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols)
Well it is OT but because you linked it, I think what he describes there is also a good case for a good general education with a broad spectrum even if most of that knowledge will never be needed for for an employment.
Of course "social" media oppinion bubbles just makes the situation much worse.

   I have had a few people ask me about testing AC line devices which point to just how ignorant some viewers are.  I don't see that changing although I run into it less and less.       


I don't know what the "ignorant" people asked from you, but both general household appliances, and especially the common surge protectors are a very interesting topic with all sensitive elctronics to find in an everage household. And the protection itself is very similar to what you can find in the multimeter.
So though you would of course classify me as ignorant too, but I would be really interested in both how an appliance (can be anything like a modern washing machine control board) behaves just with a 2-3000 V small voltage spike what your generator outputs, what different surge protectors let through, and of course what happens if a surge protector really meets with its thaoretical 30-70Ka rating.
(Yes I know that it is not your generator...)
Possibly a huge amount af goods is getting damaged because of this, even without any serious lightning strike or similar big issue.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 27, 2021, 01:12:37 pm
The damaged meter was a Dick Smith Q1425 and has a 40 pin ICL7106CPL dated 10/94 so almost 27 years old but in immaculate condition for its age.
Another 10 years or so and it would probably have been manufactured in Japan.

https://www.youtube.com/watch?v=0ZEgluZJpBM (https://www.youtube.com/watch?v=0ZEgluZJpBM)
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 27, 2021, 02:59:15 pm
...
Is it a third party independent testing a better scenario than self-certification or reputation alone? Yes, of course, especially since most people don't understand the technicalities of what they are buying
So our views coincide on the matter of independent certification.
- unfortunately this hasn't been he ideal scenario as time and time again it has been proven it is caveat emptor. That is why youtube and the internet have been acting as a "fourth party" source of information.
The problem with relying on information from YouTube or any other form of social media rather than information from independent testing and certification companies is quite obvious to me. If you have to take any information from independent testing and certification companies with a grain of salt, information on social media requires a truckload of skepticism and common sense - and time. Since I don't have much common sense and very little time, I always prefer to rely on information from independent testing and certification companies, however flawed it may prove to be in some cases.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 03:36:18 pm
.... If it were, we would all be experts at everything.  ...

We are! 

https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols (https://www.harvardmagazine.com/2018/03/death-of-expertise-by-tom-nichols)
Well it is OT but because you linked it, I think what he describes there is also a good case for a good general education with a broad spectrum even if most of that knowledge will never be needed for for an employment.
Of course "social" media oppinion bubbles just makes the situation much worse.

I've read his book and recommend it.   

   I have had a few people ask me about testing AC line devices which point to just how ignorant some viewers are.  I don't see that changing although I run into it less and less.       


I don't know what the "ignorant" people asked from you, but both general household appliances, and especially the common surge protectors are a very interesting topic with all sensitive elctronics to find in an everage household. And the protection itself is very similar to what you can find in the multimeter.
So though you would of course classify me as ignorant too, but I would be really interested in both how an appliance (can be anything like a modern washing machine control board) behaves just with a 2-3000 V small voltage spike what your generator outputs, what different surge protectors let through, and of course what happens if a surge protector really meets with its thaoretical 30-70Ka rating.
(Yes I know that it is not your generator...)
Possibly a huge amount af goods is getting damaged because of this, even without any serious lightning strike or similar big issue.

I am not aware of any appliances that use surge rated resistors in series with PTC and then shunted with MOVs, with selectable low voltage clamps made from back to back transistors.    I have had people write me about running my tests too fast and over heating the MOVs in the DMMs. 

People have asked me about running devices which would attach to the mains like power supplies and surge protectors across my generator.  Yes, very ignorant. Sadly, the people who ask I expect lack the basic education to understand even the basics of what has been shown, so I don't see an easy fix.     
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 27, 2021, 03:41:52 pm
Another 10 years or so and it would probably have been manufactured in Japan.
"all the best stuff is made in Japan..."

That perception changes with time and marketing and the kind of "stuff" we are talking about. Also the average American has a hard time telling one Asian country apart from another.

For PC motherboards, "all the best stuff is made in Taiwan..."
For LCD/OLED TVs and monitors, "all the best stuff is made in South Korea..."
Of the EEVblog DMMs, I believe two are made in Taiwan and one in South Korea?

And the way things are going, sooner or later, all the popular "best stuff" will be made in China, even if it is sold under a Western or Taiwanese or Japanese brand. Including digital multimeters.
Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 27, 2021, 04:32:23 pm


I am not aware of any appliances that use surge rated resistors in series with PTC and then shunted with MOVs, with selectable low voltage clamps made from back to back transistors.    I have had people write me about running my tests too fast and over heating the MOVs in the DMMs. 

People have asked me about running devices which would attach to the mains like power supplies and surge protectors across my generator.  Yes, very ignorant. Sadly, the people who ask I expect lack the basic education to understand even the basics of what has been shown, so I don't see an easy fix.   

I understand that it is not exacly the same setup,but it is similar, by means of trying to clamp down an overvoltage to save a microcontroller, and other sensitive stuff.
Even small energy spikes get through the main lines which damage equipment.
And it is indeed interesting, what different surge protectors can let through from even these small energy spikes.
So if you mean it is ignorance because the small energy involved, than again, you don't necessary have huge surges on the AC line. The waveform of course is different. That is what you mean? But actually... it also does not have to be entirely different...
And with a surge protector it is quiet interesing what they actually let through from these smaller spikes.
1000V? 300V? With what rise time? Same with the named control board: What is a maximal small surge it can handle?

And regarding testing a surge protector with a massive surge, well that though needs a different generator or condensator bank, but again, still an interesting topic, and not many people can or will present it with attached proper measuring equipment.
 






Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 27, 2021, 05:12:11 pm
The problem with relying on information from YouTube or any other form of social media rather than information from independent testing and certification companies is quite obvious to me. If you have to take any information from independent testing and certification companies with a grain of salt, information on social media requires a truckload of skepticism and common sense - and time. Since I don't have much common sense and very little time, I always prefer to rely on information from independent testing and certification companies, however flawed it may prove to be in some cases.

I certainly agree that the signal-to-noise noise to signal ratio on YouTube, or even EEVBlog can be quite high.  But you make it seem as if there are only two choices--social media or Intertek--and that your decisions somehow need to be made on technical merits.  You say you 'prefer to rely', which to me means 'choose to believe'--a silly concept IMO, but we'll go with it.  I opt to rely on a the technical merit and integrity of companies that have provided excellent products that have served me and others reliably, sometimes under very tough conditions, for decades.  When I see a company that has been producing utter rubbish for those same decades come out with a product that 'competes' at less than 1/10 the price and then hangs a 'certification' on it, I don't need any technical expertise to know to regard those claims as highly suspect.  But still you have those who go for it, perhaps because they can't resist the allure of a cheap deal, and then even go so far as to criticize the reliable, reputable A-brand for not hanging higher ratings on their meters.

I would just let that go as consumer idiocy, except that the rating part just bothers me.  There are people who rely on those ratings in a very real way, unlike the average hobbyist, consumer or even light-duty electrician.  If someone in a management position thinks, like you do, that UL or Intertek ratings are a reliable indicator of quality, they may end up buying that rubbish for an application where it counts.

A Fluke 28-II or 87V-MAX will be rated CAT III/1000V, CAT IV/600V and IP67.  They are made by Fluke in the US and cost around $500 or so--and have the limited lifetime warranty.  The Southwire 11060S is also CAT III/1000V, CAT IV/600V and IP67, all certified by UL.  They are made by Shenzhen Everbest (CEM) and cost around $100.  I do not know what branch of the UL did the certification, but I doubt they mailed their samples to Pennsylvania.  So likely the same story--certification done by local Chinese branch.  I have no idea if that matters.

https://www.electriciantalk.com/attachments/xlhhln0-png.138650/ (https://www.electriciantalk.com/attachments/xlhhln0-png.138650/)

"examination and testing....revealed that the meter's design and manufacture was not consistent with its Underwriters Laboratory (UL) listing."

https://www.govinfo.gov/content/pkg/USCOURTS-kyed-7_14-cv-00175/pdf/USCOURTS-kyed-7_14-cv-00175-0.pdf (https://www.govinfo.gov/content/pkg/USCOURTS-kyed-7_14-cv-00175/pdf/USCOURTS-kyed-7_14-cv-00175-0.pdf)

So there you go.  And if you read the case, you can see that Southwire was able to walk away by disclaiming any knowledge of the particulars of the products that they sold with their name on them.  So if you just like having those ratings printed on the front and don't care how well they are backed up because you don't actually need them, go for the deal.  In my view, this should be a criminal matter, but there's just too many people making money to let a burned electrician get in the way of prosperity.



Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 27, 2021, 05:25:56 pm
Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.

So I'm curious about why these tests would be conducted at those levels on meters with a CAT-anything label at.  Should the meter not withstand, without damage, the application of full rated voltage (1000V in this case) to any input on any setting?  AFAIK, even supposedly fragile CAT I bench meters will pass that test.  Some older pre-CAT bench meters have separate, lower specifications for voltage protection on ohms and such, but even the old Fluke 8842A will pass that test.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 27, 2021, 05:51:12 pm
Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.

So I'm curious about why these tests would be conducted at those levels on meters with a CAT-anything label at.  Should the meter not withstand, without damage, the application of full rated voltage (1000V in this case) to any input on any setting? 

That's the theory but you never know for sure.

eg. A freebie DT830 will measure 1000V on the voltage range but I bet it wouldn't survive on one of the resistance ranges and I know it wouldn't survive on a current range.

Meters with "1000V" printed on the front and 250V fuses in them are quite common in the $25-meter world.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 27, 2021, 06:06:16 pm
...
Is it a third party independent testing a better scenario than self-certification or reputation alone? Yes, of course, especially since most people don't understand the technicalities of what they are buying
So our views coincide on the matter of independent certification.
Indeed. Why wouldn't someone want a reliable third party that verifies a manufacturer's claims in a very reproducible, reliable and uncompromised way? We don't have this today. That is the gist of the discussion.

- unfortunately this hasn't been he ideal scenario as time and time again it has been proven it is caveat emptor. That is why youtube and the internet have been acting as a "fourth party" source of information.
The problem with relying on information from YouTube or any other form of social media rather than information from independent testing and certification companies is quite obvious to me. If you have to take any information from independent testing and certification companies with a grain of salt, information on social media requires a truckload of skepticism and common sense - and time. Since I don't have much common sense and very little time, I always prefer to rely on information from independent testing and certification companies, however flawed it may prove to be in some cases.
I fully understand your stance, as there are things in life that I have to rely on an evaluation from a cert or government agency - food, utilities (gas, water) and pharmaceuticals being a few of them. Regardless, it only takes you to get burned once or twice by a product that was supposedly evaluated from these agencies to make you get smart about it. Examples galore, both in this thread with something of a niche product such as a multimeter and of more general public interest, such as the scandal where several cities in the state of Michigan had lead poisoned water for decades.

The SNR of the Internet and Youtube, although narrow, is of great use to provide an outlet to bring discussions to light that were unthinkable a few decades ago. Myself and many people I know rarely do a capital expense without looking at reviews, videos, opinions on the internet, as UL/Intertek/TÜV certified logos only do so much to let a ton of crap to the marketplace (and there is even the subject of falsifications).

The Southwire example pointed out by bdunham7 is a good example. Southwire and CEM probably have an indemnification clause where the ODM takes all responsibility for their crap, and any legal battles must be solved in the COO (China in this case). And THAT'S the kind of legal crap that cert and government agencies and OEMs find to skirt the law and reduce their seriousness and trust with the general public.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 27, 2021, 06:08:09 pm
That's the theory but you never know for sure.

 :o

I'm referring to meters that some claim to be properly rated, not ones where there isn't any dispute that the CAT info printed on them is a bad joke.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 06:59:44 pm
I understand that it is not exacly the same setup...

Again, they are not even close.  And again, the generator was designed not to simulate AC mains conditions, or anything even close to it. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 07:08:15 pm
Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.

So I'm curious about why these tests would be conducted at those levels on meters with a CAT-anything label at.  Should the meter not withstand, without damage, the application of full rated voltage (1000V in this case) to any input on any setting?  AFAIK, even supposedly fragile CAT I bench meters will pass that test.  Some older pre-CAT bench meters have separate, lower specifications for voltage protection on ohms and such, but even the old Fluke 8842A will pass that test.

Link to the persons posts who had asked about this may be found here:
https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/ (https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/)

Some of the smaller PTCs are only rated for 500V.  Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them....  Maybe....  Turn the dial, I suspect you will get a light show. 

***
Quote
I'm referring to meters that some claim to be properly rated, not ones where there isn't any dispute that the CAT info printed on them is a bad joke.

Sorry, I missed that part.   If a KVDC were applied with unlimited current and the function switch were rotated, I suspect you would burn the contacts on most meters.  I wouldn't recommend anyone attempt it.   

 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 27, 2021, 07:14:37 pm
Again, they are not even close.  And again, the generator was designed not to simulate AC mains conditions, or anything even close to it.

Do they need to be?  HiPot testing is a valid method of looking at potential HV breakdown (obviously not L-L in a normal operating mode) without riding on any mains, so why not consider it as transient HiPot method?  It certainly would at least be a usable diagnostic tool that can be used to non-destructively find weak points.  One would have to learn how to interpret the results just like you do with an old engine analyzer ignition scope.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 27, 2021, 07:23:10 pm
Some of the smaller PTCs are only rated for 500V.  Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them....  Maybe....  Turn the dial, I suspect you will get a light show.

Well that doesn't sound very robust!  I don't know if that is a failure to meet a standard or not, but it seems like a basic expectation to me.  Every CAT labelled meter I currently have that isn't known junk should pass that test.  Some of them already have by accident.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 07:33:25 pm
Again, they are not even close.  And again, the generator was designed not to simulate AC mains conditions, or anything even close to it.

Do they need to be?  HiPot testing is a valid method of looking at potential HV breakdown (obviously not L-L in a normal operating mode) without riding on any mains, so why not consider it as transient HiPot method?  It certainly would at least be a usable diagnostic tool that can be used to non-destructively find weak points.  One would have to learn how to interpret the results just like you do with an old engine analyzer ignition scope.
So you are suggest to use a high pot tester across the meter with it set to the volts mode? 

I've seen a few people post videos (including Dave) using an insulation tester. 

There was a guy posting about using a stun gun to test meters.  I wrote them but they never responded.   

Another option would be to actually get a combo generator tied to the mains and a nice blast shield.

All fun ideas and if anyone starts a channel where they run the meters this way, I will watch. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 07:41:01 pm
Some of the smaller PTCs are only rated for 500V.  Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them....  Maybe....  Turn the dial, I suspect you will get a light show.

Well that doesn't sound very robust!  I don't know if that is a failure to meet a standard or not, but it seems like a basic expectation to me.  Every CAT labelled meter I currently have that isn't known junk should pass that test.  Some of them already have by accident.

Maybe start reading here.  Dave chimes in.  So do I. 
https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1580530/#msg1580530 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1580530/#msg1580530)
Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 27, 2021, 08:11:08 pm

So you are suggest to use a high pot tester across the meter with it set to the volts mode? 

I've seen a few people post videos (including Dave) using an insulation tester. 

There was a guy posting about using a stun gun to test meters.  I wrote them but they never responded.   

Another option would be to actually get a combo generator tied to the mains and a nice blast shield.

All fun ideas and if anyone starts a channel where they run the meters this way, I will watch.

What would be the most important difference with a mains voltage spike with lets say 3000V P-P with the same energy level that your generator creates, to a spike 3000V p-p with your generator?
Just because it is half wave? There are no half wave spikes on the AC line?

But to turn around the argumentation, if the effects of spikes on the mains are so different(same joule level), than your generator shoud simulate rather those, because those will most likely hit the meter.

But you see I am that kind of ignorant who is trying to get an expert oppinion even if seek a bit more detailed one :)

Edit: Or what you could mean the aftermath of the possible shorts with main condition? Because like bdunham7 says after any breakdown(or letting through spikes) the interpretation is up to the viewer.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 09:57:35 pm
What would be the most important difference with a mains voltage spike with lets say 3000V P-P with the same energy level that your generator creates, to a spike 3000V p-p with your generator?

The short circuit current waveform will not be even remotely close to correct, the FWHH is twice what is called out, lack of a coupling network, lack of a way to synchronize it or change the phase, lack of polarity selection, lack of support for both 50/60 Hz, lack of ability to select the mains amplitude.   I think I would also like to run burst as well as surge.  There are also several other tests that would be performed.   

Just because it is half wave? There are no half wave spikes on the AC line?

But to turn around the argumentation, if the effects of spikes on the mains are so different(same joule level), than your generator shoud simulate rather those, because those will most likely hit the meter.

Where did you get the idea that they have the same energy levels?  You assume I am using these meters on the mains.  I've been pretty clear about that.   While there are standards in place for qualifying various devices for mains use,  this is not what I have been showing over the last few years.

But you see I am that kind of ignorant who is trying to get an expert oppinion even if seek a bit more detailed one :)

Edit: Or what you could mean the aftermath of the possible shorts with main condition? Because like bdunham7 says after any breakdown(or letting through spikes) the interpretation is up to the viewer.

Your opinion is that the waveforms I use to test the meters are adequate to test mains devices.  My opinion is that you're ignorant on AC mains testing.  Of course, you could start doing some research if it interests you and correct that deficiency but you will not find many details in this thread about it.
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 27, 2021, 09:58:43 pm
What happens is the PTC is slow to heat up and increase in resistance, which over-stresses the diode-connected transistors too much and they fail. I think this is why Fluke and Brymen include the 1k surge-resistor.

[...] Some of the smaller PTCs are only rated for 500V.  Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them....  Maybe....  [...]

The chinese PTC's are really too cheap/small and I noticed rated 550WV and 1,000V max. at 1.1k ohms. Who knows what the "max rating". It's hard to find real 1,000V-rated PTC's with regulatory approvals.
Uni-T has used the MZ11-07M112M550 but I saw Russian UT-61's with even cheaper (smaller, no epoxy) version parts.

No mention of the details of modifications to the UT-61E+?  the clamp transistors "better" or "more expensive"? I'm not sure that is helpful.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 27, 2021, 10:29:22 pm
The surge rated resistors are at least designed for it and I would guess are part of the safety requirements. 

For a swag at 2kV peak, MOVs are say 1kV, so 2kV transient - 1kV MOVs leaves 1kV divided across the resistor and PTC.   If they were both 1kohms at DC, that's 500V each and a half mil peak current.  I suspect the thermal mass of the PTCs prevent it from responding to the transients I apply.  Seems I made a video on this when looking at the 87V. 

I don't think I have seen any PTCs without a coating being used in the handheld meters I have looked at. 

You are correct.  I have not, nor will I post any details about the parts I am using in the UT61E+.  I have heard it all before but you are certainly free to add your own twist.  That said, I really have no way to know if those parts improved it.  As I said, the stock meter may have performed just as well.  The only way to know would be to repeat it.
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 28, 2021, 01:42:33 am
I understand. Still disconcerting the UT61E+ LCD display flickering during the BBQ lighter tests, it might be an EMC issue. I hope the IC is not getting damaged.
One could look at the input current to a multimeter during an ohms-function overload, to see the PTC heat up and settle.

I looked at several Uni-T 61010 test reports and it seems they are capable of making something strong enough, but it must be cost. They save every penny.
chinese regulatory reports are notorious for checking "not applicable" and skipping entire suites of tests on products.
If you put a multimeter through 61010 approvals as a "3V device" basically like testing a flashlight lol. No need for 90% of the safety tests and at the end you can say it passed... as long as the User Manual says certain things forbidding use at hazardous voltages.

Thanks Dave for the Sanwa PM300 "Verification of Compliance", I had big doubts. The Japanese engineers I've worked with are baffled by people making mistakes and damaging test equipment. They can't imagine improper use, who could be so stupid. The meter should explode and kill the user, or just Harakiri afterwards.
But... oddly tested by SGS-CSTCT (china) so I've asked for more details. I don't trust the certs coming out of there.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 28, 2021, 03:03:44 am
I understand. Still disconcerting the UT61E+ LCD display flickering during the BBQ lighter tests, it might be an EMC issue. I hope the IC is not getting damaged.
One could look at the input current to a multimeter during an ohms-function overload, to see the PTC heat up and settle.  ...

If I was applying DC then sure but the transients I apply have a fairly fast rise time with an exponential decay.  There's no settling until after it's all said and done.   As I previously wrote:
Quote
I suspect the thermal mass of the PTCs prevent it from responding to the transients I apply.

PTC_T1, showing a test board with a couple of 1k resistors in series with a 1k PTC.   For this test, the MOVs are shorted with a jumper.

PTC_T2, showing a close up.  The transient generator attached to one side of a 1k resistor.  Scope attached to the output of the generator and to the PTC. 

PTC_T3, showing the whole setup.   

Notice that the transient voltage (gold) is divided across the two resistors and the PTC, all being roughly 1k ohms.   Notice how the voltage across the PTC (pink) remains ratiometrically stable with the transients voltage.   Again, it's stable because there is just too much thermal mass for it to respond.   If the PTC's resistance were to change, you surely understand that we would no longer see this ratiometric divider?  Rather more and more voltage would be across the PTC.

I could turn up the generator (would require different probes) and we would continue to see the same profile.   
Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 28, 2021, 10:11:54 am
What would be the most important difference with a mains voltage spike with lets say 3000V P-P with the same energy level that your generator creates, to a spike 3000V p-p with your generator?

The short circuit current waveform will not be even remotely close to correct, the FWHH is twice what is called out, lack of a coupling network, lack of a way to synchronize it or change the phase, lack of polarity selection, lack of support for both 50/60 Hz, lack of ability to select the mains amplitude.   I think I would also like to run burst as well as surge.  There are also several other tests that would be performed.   

Just because it is half wave? There are no half wave spikes on the AC line?

But to turn around the argumentation, if the effects of spikes on the mains are so different(same joule level), than your generator shoud simulate rather those, because those will most likely hit the meter.

Where did you get the idea that they have the same energy levels?  You assume I am using these meters on the mains.  I've been pretty clear about that.   While there are standards in place for qualifying various devices for mains use,  this is not what I have been showing over the last few years.

But you see I am that kind of ignorant who is trying to get an expert oppinion even if seek a bit more detailed one :)

Edit: Or what you could mean the aftermath of the possible shorts with main condition? Because like bdunham7 says after any breakdown(or letting through spikes) the interpretation is up to the viewer.

Your opinion is that the waveforms I use to test the meters are adequate to test mains devices.  My opinion is that you're ignorant on AC mains testing.  Of course, you could start doing some research if it interests you and correct that deficiency but you will not find many details in this thread about it.


Thanks for the more detailed explanation, but if I am not completely wrong, we might talk about two different thing. (You talking about coupling network, 50/60 Hz)

What you are talking about is a simulation of a full sugre event on the mains line. So after the spike, and the clamping you still have the energy pumped in and causing damage, or at least effects.

But what I was talking about (and maybe bdunham7 also) is just the voltage spike itself without mains connected. And if the rise time is the same, the peak voltage is the same and the energy as well, than the short circuit current waveform during that small spike can not be that different.
And it is not the same as an insulation tester, because it is just a short spike, so what is interesting
is the clamping speed and level. The different polarities could be the only thing which is missing, but that is not a problem, or you could just change the polarity manually for the sake of one spike.

So it would NOT be a simulation of what would happen if the same spike would come in on the mains, but only whether the single spike itself would at all get through the surge arrester (or the one single MOV in some electronics) in any form. Would it let through a short 1000V peak from 3000 V? Or only 300V?  Different rise times?

So yes, different to what would happen with the mains event, but still enough to see how fast it clamps, and at which voltage. Of which the manufacturers never really tell anything.
If a manufacturer will cheap out in the protection, and want to build a product which is cheap, and doesn't go wrong over time, than it just chooses a MOV with such a high value, that it will never really
protect anything. And probably that is what happens most of the time, and most of the spike would get through.

Just like your tests with the multimeters are not safety tests, and not simulating a huge energy event, this would also not be an AC line surge test, but still interesting to check the claping level and speed.



Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 28, 2021, 10:53:24 am
...
I certainly agree that the signal-to-noise noise to signal ratio on YouTube, or even EEVBlog can be quite high.  But you make it seem as if there are only two choices--social media or Intertek--and that your decisions somehow need to be made on technical merits.  You say you 'prefer to rely', which to me means 'choose to believe'--a silly concept IMO, but we'll go with it.  I opt to rely on a the technical merit and integrity of companies that have provided excellent products that have served me and others reliably, sometimes under very tough conditions, for decades.
...

That's called "reputation" and if you "choose to believe" in the reputation of any particular company, that's your subjective choice, based on a) your personal anecdotal experience, b) the anecdotal experience of others and c) a carefully constructed brand image. I prefer to rely on independent testing and certification reports which despite all their flaws, are an objective criteria.

A review of any testing equipment that emphasizes subjective criteria is, in my opinion, a poor review - and that's what you mostly find on YouTube and social media in general. When it comes to safety, a good review should always mention whether a piece of test equipment is or not independently certified, by which certification company, and to what standards.

As Dave has mentioned, most test equipment made in China is not independently certified at all. All the more reason to carefully review the few rare ones that are, whether they are priced at 15€ (including shipping and taxes) or above 200€.

You seem to have such contempt for anything made in China that you wrote off the UNI-T UT125C right off the bat, even though I have linked to its certification by Intertek. Then you dismissed the Intertek Shenzhen "branch" as an unreliable independent certification company, and when I pointed out to you that there is no such thing as an Intertek Shenzhen "branch" (Intertek have 12 different offices in Shenzhen alone), you decided to cast doubt on all independent certification companies and the independent testing and certification process itself.

I guess there is no end to your arrogance.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 28, 2021, 11:10:29 am
...
The short circuit current waveform will not be even remotely close to correct,
...
Where did you get the idea that they have the same energy levels? 
...
Your opinion is that the waveforms I use to test the meters are adequate to test mains devices.  My opinion is that you're ignorant on AC mains testing.  Of course, you could start doing some research if it interests you and correct that deficiency but you will not find many details in this thread about it.

Thanks for the more detailed explanation, but if I am not completely wrong, we might talk about two different thing.
...
And if the rise time is the same, the peak voltage is the same and the energy as well, than the short circuit current waveform during that small spike can not be that different.
...

While I could continue to explain to you that the energy is not the same,  you would ignore it.   I asked
Quote
Where did you get the idea that they have the same energy levels? 
thinking I may be able to explain where your thinking is flawed but you refused to answer.    Ignorance can be overcome easily with education but I suspect learning is also a problem for you.    It's similar to discussing the basics with the people interested in perpetual motion.  It becomes a religion to them and they can't move beyond it.

I suspect you lack in basic physics.  Somehow you feel that if you have two voltage waveforms that look identical, have the same source impedance and even the same peak current, that means they have the same energy available. 
Title: UNI-T UT61E+ vs UT161E
Post by: AndrewBCN on September 28, 2021, 11:31:53 am
Just a note: the UNI-T UT61E+ that Joe is testing these days is not independently certified. On the other hand, the UT161E, which externally seems identical, is certified by Intertek (from the manual: "Conforms to UL STD 61010-1, 61010-030, 61010-2-033, Certified to CSA STD C22.2 No. 61010-1, 61010-030, 61010-2-033.")

The cost of these two DMMs, including VAT and shipping to France:

- UT61E+: 73€ shipped from China (2 to 3 weeks).
- UT161E: 75€ shipped from Spain (3 to 7 days).

Personally I would rather pay an extra €2 and get the certified UT161E.

- UT61E+ manual (PDF): https://www.uni-trend.com/uploadfile/2020/1101/20201101050334873.pdf (https://www.uni-trend.com/uploadfile/2020/1101/20201101050334873.pdf)
- UT161E manual (PDF): https://www.uni-trend.com/uploadfile/2020/1101/20201101050334873.pdf (https://www.uni-trend.com/uploadfile/2020/1101/20201101050334873.pdf)

Certification (or lack thereof) is mentioned on page 6.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 28, 2021, 12:03:08 pm
That's called "reputation" and if you "choose to believe" in the reputation of any particular company, that's your subjective choice, based on a) your personal anecdotal experience, b) the anecdotal experience of others and c) a carefully constructed brand image. I prefer to rely on independent testing and certification reports which despite all their flaws, are an objective criteria.

But then you have companies like Uni-T that have a reputation for changing and omitting parts in models on a whim.
Even if they have a properly certified model with no evidence of that happening in that model, that image can still cast doubt on the company based on the subjective "feels".
As we say in Australia, it's "the vibe".
It can be hard for a company to change that image. I can remember when Brymen had a reputation as a chinky Taiwanese maker of cheap meters, it took several decades to get to where they are now.
Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 28, 2021, 12:20:58 pm
...
The short circuit current waveform will not be even remotely close to correct,
...
Where did you get the idea that they have the same energy levels? 
...
Your opinion is that the waveforms I use to test the meters are adequate to test mains devices.  My opinion is that you're ignorant on AC mains testing.  Of course, you could start doing some research if it interests you and correct that deficiency but you will not find many details in this thread about it.

Thanks for the more detailed explanation, but if I am not completely wrong, we might talk about two different thing.
...
And if the rise time is the same, the peak voltage is the same and the energy as well, than the short circuit current waveform during that small spike can not be that different.
...

While I could continue to explain to you that the energy is not the same,  you would ignore it.   I asked
Quote
Where did you get the idea that they have the same energy levels? 
thinking I may be able to explain where your thinking is flawed but you refused to answer.    Ignorance can be overcome easily with education but I suspect learning is also a problem for you.    It's similar to discussing the basics with the people interested in perpetual motion.  It becomes a religion to them and they can't move beyond it.


I did not ignore your question, but the starting assumption of the discussion was this, and I supposed you read it:


I understand that it is not exacly the same setup,but it is similar, by means of trying to clamp down an overvoltage to save a microcontroller, and other sensitive stuff.
Even small energy spikes get through the main lines which damage equipment.
And it is indeed interesting, what different surge protectors can let through from even these small energy spikes.
So if you mean it is ignorance because the small energy involved, than again, you don't necessary have huge surges on the AC line.

You did not argue with this statement. That is why I asked you what else can be so dramatically different if we are talking about LOW ENERGY SURGES. But than you got back to the energy level.
If I commented this in your style would that raise the quality level of the discussion?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 28, 2021, 01:32:13 pm
I did not ignore your question, but the starting assumption of the discussion was this, and I supposed you read it:


I understand that it is not exacly the same setup,but it is similar, by means of trying to clamp down an overvoltage to save a microcontroller, and other sensitive stuff.
Even small energy spikes get through the main lines which damage equipment.
And it is indeed interesting, what different surge protectors can let through from even these small energy spikes.
So if you mean it is ignorance because the small energy involved, than again, you don't necessary have huge surges on the AC line.

You did not argue with this statement. That is why I asked you what else can be so dramatically different if we are talking about LOW ENERGY SURGES. But than you got back to the energy level.
If I commented this in your style would that raise the quality level of the discussion?

There's no argument.  To raise the quality of the discussion, I would expect you to bring more to the table.  My advice would be to start a new thread on AC appliance testing or what ever your area of interest is.   Explain what your goals are.   Define these small energy spikes you are talking about.  Show where they have caused problems.   Show how they compare with the IEC standards.   It's nothing I would have any interest in but I suspect you would find others would chime in.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 28, 2021, 01:44:02 pm
It can be hard for a company to change that image. I can remember when Brymen had a reputation as a chinky Taiwanese maker of cheap meters, it took several decades to get to where they are now.

Considering it took me several decades to own another Fluke product at home because the price/performance was so poor with the first one I bought, it's not unique to Brymen.  There's a learning curve and even Fluke continues to evolve.   


Depending how my testing goes, I may have to buy another UT61E+ just to satisfy my own curiosity.  If it survives what the low voltage generator can put out, I think it's going to deserve a closer look...  Of course, if I buy a second one, it may have a whole new circuit design... :-DD
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 28, 2021, 02:27:08 pm
...
But then you have companies like Uni-T that have a reputation for changing and omitting parts in models on a whim.
...

That's anecdotal, and even though it matters for a company's reputation or "vibes", objectively you would have to comparatively test to see how it affects the product's performance or safety.

And since we are on the level of anecdotes, I can point out that my 2021 15€ Intertek-certified UNI-T UT125C is indeed slightly different from that reviewed by HKJ three years ago: apparently it has an extra clamping diode in the input circuit.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 28, 2021, 02:34:44 pm
I prefer to rely on independent testing and certification reports which despite all their flaws, are an objective criteria.

Are you sure they are objective?  How do you know?  And is 'objectivity' really a goal unto itself?  I may be opinionated, but right (of course that's what I think) and someone else may be 'objective' but utterly incompetent.  Or, the company may screw with the system in other ways.  Or, the actual testing and certification might not cover a particular aspect that is very important to me or any other customer.  Unless you actually have, read and understand the CAT III criteria, what good does it really do you to know that it is 'certified' to meet that standard? Anyway, good for you--you can do as you please.

Quote
A review of any testing equipment that emphasizes subjective criteria is, in my opinion, a poor review - and that's what you mostly find on YouTube and social media in general.

Oh bullshit!  A 'good review' is a review of whatever the reviewer chooses to review--aesthetics, accuracy, ease of use, whatever you like.  A 'certified' DMM that takes 18 seconds to autorange, for example, would be something a good reviewer might point out.  Reviewers, users and other lesser contemptibles have occasionally found or demonstrated flaws in 'certified' products that are later corrected by the manufacturer.  Things like light causing errors through the IR port and GSM phones bricking meters. 

Quote
You seem to have such contempt for anything made in China that you wrote off the UNI-T UT125C right off the bat, even though I have linked to its certification by Intertek. Then you dismissed the Intertek Shenzhen "branch"

Where have I expressed this broad contempt for anything made in China and what reasoning leads you to the conclusion that I would dismiss the UT125C because of its nationality?  And why do you think that 'branch' is wrong and 'office' is right?  Do you have extensive knowledge about the internal organization of multi-national global companies in general or Intertek in particular?

Quote
I guess there is no end to your arrogance.

I would have expected you to call me ignorant, 'arrogant' seems odd somehow.  But in any case, if contempt for a company that makes rubbish meters and gets a few of them independently certified but prints CAT markings on all of them makes me arrogant, I'll wear the badge proudly arrogantly.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 28, 2021, 02:51:16 pm
That's anecdotal, and even though it matters for a company's reputation or "vibes", objectively you would have to comparatively test to see how it affects the product's performance or safety.

Seriously?  So if a car company gets a model past the NCAP crash test and then subsequently starts omitting the airbags, you would dismiss that as 'anecdotal' and require new crash tests before you could conclude that the company was unethical or that the car was unsafe?  I'm not all sure that you comprehend how things work.  If a product is 'certified', then the products have to be manufactured in the same way as the exemplars.  To do otherwise is fraud, no matter how you try to paper around it.

And b/t/w, a meter missing parts is not 'anecdotal', it is physical evidence. 

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 28, 2021, 03:46:04 pm
But what I was talking about (and maybe bdunham7 also) is just the voltage spike itself without mains connected. And if the rise time is the same, the peak voltage is the same and the energy as well, than the short circuit current waveform during that small spike can not be that different.

Just to be clear, what I was referring to would be something completely different, and a diagnostic or analytical tool not a test.  I don't have the time or inclination to pursue it at the moment, so I'll just point out that the whole situation with spikes and energy isn't that simple.  For example, it is entirely possible for a surge to 'get through' and damage a microprocessor without ever causing any arcing or even clamping in a protective circuit, so damage to equipment is not perfectly correlated to potential for arc or fire hazards.  There are already standards for this, so if you were going to rig something up, I'd start there.  One issue that you'd have to consider is that an AC mains connected device is in a low-impedance circuit and you can't really have low energy, low impedance and high voltage--so something has to give.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 28, 2021, 04:32:19 pm
There are already standards for this, so if you were going to rig something up, I'd start there.

A few years back, someone was selling off a pallet of test equipment for AC line testing.   Looked like a lab had closed and they were selling off the assets.   If I were going to toe dip into this area, I would try and find another deal like this. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 28, 2021, 04:41:25 pm
A few years back, someone was selling off a pallet of test equipment for AC line testing.   Looked like a lab had closed and they were selling off the assets.   If I were going to toe dip into this area, I would try and find another deal like this.

If I wanted a YouTube channel to compete with ElectroBOOM, that would be the way to go!  Buy cheap crap on Amazon and blow it up, all with big, official looking equipment.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 28, 2021, 05:04:38 pm
A few years back, someone was selling off a pallet of test equipment for AC line testing.   Looked like a lab had closed and they were selling off the assets.   If I were going to toe dip into this area, I would try and find another deal like this.

If I wanted a YouTube channel to compete with ElectroBOOM, that would be the way to go!  Buy cheap crap on Amazon and blow it up, all with big, official looking equipment.
Hire a good looking female to narrate it for you and you will have a million followers in no time. 
Title: Re: UNI-T UT61E+ vs UT161E
Post by: Fungus on September 28, 2021, 06:12:30 pm
Just a note: the UNI-T UT61E+ that Joe is testing these days is not independently certified. On the other hand, the UT161E, which externally seems identical, is certified by Intertek (from the manual: "Conforms to UL STD 61010-1, 61010-030, 61010-2-033, Certified to CSA STD C22.2 No. 61010-1, 61010-030, 61010-2-033.")

The cost of these two DMMs, including VAT and shipping to France:

- UT61E+: 73€ shipped from China (2 to 3 weeks).
- UT161E: 75€ shipped from Spain (3 to 7 days).

Personally I would rather pay an extra €2 and get the certified UT161E.

Do you know about the different versions of the 61E, with varying amounts of input protection?

Here's two of them side by side:
(https://image.ibb.co/fQs2yH/Uni_t.jpg)

Which "UT61E" do you claim is certified? Which one do you think you'll get for 75 Euros? Better cross your fingers when you order...

Ref: https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/msg1437056/#msg1437056 (https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/msg1437056/#msg1437056)

Title: Re: Handheld meter robustness testing
Post by: armandine2 on September 28, 2021, 06:15:53 pm
"If I wanted a YouTube channel to compete with ElectroBOOM"


He is, from what I can see, a teacher -  the upbeat performance of teaching is felt necessary nowadays to capture the attention of children. But, note  he isn't a slouch and will go after the careless physics professor!
Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 28, 2021, 06:20:38 pm
But what I was talking about (and maybe bdunham7 also) is just the voltage spike itself without mains connected. And if the rise time is the same, the peak voltage is the same and the energy as well, than the short circuit current waveform during that small spike can not be that different.

Just to be clear, what I was referring to would be something completely different, and a diagnostic or analytical tool not a test.  I don't have the time or inclination to pursue it at the moment, so I'll just point out that the whole situation with spikes and energy isn't that simple.  For example, it is entirely possible for a surge to 'get through' and damage a microprocessor without ever causing any arcing or even clamping in a protective circuit, so damage to equipment is not perfectly correlated to potential for arc or fire hazards.  There are already standards for this, so if you were going to rig something up, I'd start there.  One issue that you'd have to consider is that an AC mains connected device is in a low-impedance circuit and you can't really have low energy, low impedance and high voltage--so something has to give.

Well, if you read through my comments, I actually never even used the word "arc", so we are talking about the same issue. If I wrote "Test" and everybody interpreted it as an official test following som standards... well than, that was a mistake, and from now on I will use the word EXPERIMENT. :)  .
I hope we are not ignorant to have some interest in this.

Here is an old paper:
https://www.nist.gov/system/files/documents/pml/div684/Residential_Surges.pdf (https://www.nist.gov/system/files/documents/pml/div684/Residential_Surges.pdf)
And a never one:
https://www.nfpa.org/-/media/Files/News-and-Research/Fire-statistics-and-reports/Electrical/RFDataAssessmentforElectricalSurgeProtectionDevices.ashx (https://www.nfpa.org/-/media/Files/News-and-Research/Fire-statistics-and-reports/Electrical/RFDataAssessmentforElectricalSurgeProtectionDevices.ashx)

Especialy the low energy spikes will be hard to find any info about, because they don't cause imediate failure so it would be difficult to asess what would be the most common but already harmful energy and voltage level.But I think something well within Joes generators range.
In the recent past I was trying to find out why the lnk305 and co ICs die in huge masses in commercial equipment in a wery short time. And if there were no production issues, and not all of the equipment manufacturer is using this part in a completely wrong way, one of the culprit was these small surges.
Not much info about it even on this forum, I might open a topic once.

A few years back, someone was selling off a pallet of test equipment for AC line testing.   Looked like a lab had closed and they were selling off the assets.   If I were going to toe dip into this area, I would try and find another deal like this.

If I wanted a YouTube channel to compete with ElectroBOOM, that would be the way to go!  Buy cheap crap on Amazon and blow it up, all with big, official looking equipment.

Yes, although I hope that the one who will earn some extra money with this will also posess the scientific knowledge and interest, and equipment to properly analyze the events, and the circuits. Dave was also enjoing blowing up stuff by the way, only at the canyonig trip did I saw him to be that enthusiastic again.
And while turning the Gossens range switch. (OK the range switching revolutionized my private life as well.)
But basically every healthy man enjoys blowing up stuff!

(And to not to let someone misunderstand this, I am avare that the high energy testing is an other topic, but also interested in that one.)


Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 28, 2021, 06:37:25 pm
Especialy the low energy spikes will be hard to find any info about, because they don't cause imediate failure so it would be difficult to asess what would be the most common but already harmful energy and voltage level.But I think something well within Joes generators range.

You're going to have to define and quantify 'low energy' and fully specify the circuit characteristics and other test conditions for any further discussion to have meaning.  I wouldn't call the jqsTM transients 'low energy'.
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 28, 2021, 07:39:54 pm
Maybe Joe could set up his own agency and standards lol even for pre-screening.

CSA charges out CAD $425/hour and UL very good quality but top price, even more expensive. This is why people are going with Intertek and other agencies. They really have a monopoly - their own "university/training", expert knowledge system and free access to all standards, senior certifiers etc. They also have quotas and are pushed to make money, pound out the files every month.

Because of this, I shamefully admit to getting chinese assessment and certificate on one product simply because they are fast, efficient, low cost, high volume certs there it's major manufacturing, and if you catch any errors/omissions the quality is fine.
UL/CSA can be terribly slow and expensive, you'll get a junior certifier that knows nothing and then gets hung up on on a small design issue and wastes time dollars. Then the guy gets up to speed and leaves to another department. They'll give quotations but go way over it. No accountability for cost or the results, if in the end they bungle a certification it's entirely the manufacturer's problem/cost, per the signed contract.

[...] One could look at the input current to a multimeter during an ohms-function overload, to see the PTC heat up and settle. [...]
I meant long-term overload, such as mains applied when on the ohms function. PTC holding current might be 10mA? hard to tell temperature in the heatshrink tubing sleeve but it's going be hot.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 28, 2021, 07:45:32 pm
....generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

Keep those stories coming.  We're here all night folks.

I found another meter that has a separate path for voltage that doesn't go via the surge resistor/PTC.

It's none other than our little friend the Fluke 101!

(https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/?action=dlattach;attach=77867;image)

The voltage input goes through R2/R3/R4/R5/R6/R7/R8. The Ohms/diode/continuity/etc. goes the other way.

See, I'm not crazy!  :) :) :)


Title: Re: Handheld meter robustness testing
Post by: Neutrion on September 28, 2021, 09:40:40 pm
Especialy the low energy spikes will be hard to find any info about, because they don't cause imediate failure so it would be difficult to asess what would be the most common but already harmful energy and voltage level.But I think something well within Joes generators range.

You're going to have to define and quantify 'low energy' and fully specify the circuit characteristics and other test conditions for any further discussion to have meaning.  I wouldn't call the jqsTM transients 'low energy'.

That is what I meant. There must be some statistical data about the occurrance of these. Possibly the weaker the more common. So there must be a minimum value which definitely causes some damage.
And yes I think also  that 20 Joule is possibly well beyond that level, but also well below the rating of any surge arrestor. So although zapping an arrestor with it would not mean that that arrestor would also perform well on its rated level, but if it fails and lets through too high voltages or clamps too slow than that is definitely a fail.
Title: Re: UNI-T UT61E+ vs UT161E
Post by: bdunham7 on September 28, 2021, 11:53:38 pm
Here's two of them side by side:

So you have your choice of a CAT III/1000V meter with 600V fuses and quite a population of PTCs and MOVs or a CAT III/1000V meter with even less appropriate fuses and no MOVs.  Let's call the versions 'fail' and 'didn't even try'.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 12:13:51 am
....generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

Keep those stories coming.  We're here all night folks.

I found another meter that has a separate path for voltage that doesn't go via the surge resistor/PTC.

It's none other than our little friend the Fluke 101!
..

The voltage input goes through R2/R3/R4/R5/R6/R7/R8. The Ohms/diode/continuity/etc. goes the other way.

See, I'm not crazy!  :) :) :)

We need to start at the beginning where you wrote:

I haven't looked closely at this particular Uni-T but generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

Take your Fluke 101 and lift one of the follow pins to remove the PTC as you suggest (it's not needed for voltage).   Next apply both a DC and AC voltage to the input of the meter.   Keep the signal at a safe level (<10V).    Leave the common connector attached and remove the other.  Next inject the test voltage to the PCB where you lifted the pin and measure both the AC and DC voltages.   Report your findings. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 12:16:21 am
Here's two of them side by side:

So you have your choice of a CAT III/1000V meter with 600V fuses and quite a population of PTCs and MOVs or a CAT III/1000V meter with even less appropriate fuses and no MOVs.  Let's call the versions 'fail' and 'didn't even try'.

And lets not forget the third version that has even less parts.   These two are in a much nicer class. 
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 29, 2021, 01:14:53 am
....generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

Keep those stories coming.  We're here all night folks.

I found another meter that has a separate path for voltage that doesn't go via the surge resistor/PTC.

It's none other than our little friend the Fluke 101!

(https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/?action=dlattach;attach=77867;image)

The voltage input goes through R2/R3/R4/R5/R6/R7/R8. The Ohms/diode/continuity/etc. goes the other way.

See, I'm not crazy!  :) :) :)

(WTB I have not been following any argument in this thread, so I don't know the history here)
The surge resistor and PTC are still used in the voltage range to clamp via the two series MOVs to ground.
Once you have a clamp like for any main energy spike, then you don't need any major protection on the voltage input because of the attenuator. Maybe just a basic extra transistor clamp or something just in case.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 29, 2021, 01:21:09 am
...
But then you have companies like Uni-T that have a reputation for changing and omitting parts in models on a whim.
...

That's anecdotal, and even though it matters for a company's reputation or "vibes", objectively you would have to comparatively test to see how it affects the product's performance or safety.

Fungus posted this before, two UT-61E's.
I don't need a compartive test to tell me that one lacks all the MOV's and has smaller and lower rated fuses than the other.
EDIT: Here is my UT61E added to the right side:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1284730;image)

And there are other examples of Uni-T meters doing this. I've even had it myself were a meter I have differs a lot from one someone else has.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 02:23:07 am
...
The surge resistor and PTC are still used in the voltage range to clamp via the two series MOVs to ground.
...

No argument.  It was their comments like this:

Quote
The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

why I suggested they have a fill in the blank degree.   One way to learn is by doing, which is what I suggested they try.   It's a simple test to remove that PTC and see what happens with the voltage measurements.  Sure we know the outcome, but it appears that fungus may learn something from it.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 02:34:59 am
...
But then you have companies like Uni-T that have a reputation for changing and omitting parts in models on a whim.
...

That's anecdotal, and even though it matters for a company's reputation or "vibes", objectively you would have to comparatively test to see how it affects the product's performance or safety.

Fungus posted this before, two UT-61E's.
I don't need a compartive test to tell me that one lacks all the MOV's and has smaller and lower rated fuses than the other.
EDIT: Here is my UT61E added to the right side:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1284730;image)

And there are other examples of Uni-T meters doing this. I've even had it myself were a meter I have differs a lot from one someone else has.

The discussion evolves around safety and certifications.  I don't know what the pass/fail criteria is for safety, only what I was told from two different companies that had very different interpretations.   I assume all three flavors have been certified for use in CAT III 600 or what ever they are marked for.  Is the cert worth anything?    Personally, I have bad vibes about the whole process.   :-DD
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 03:10:37 am
(WTB I have not been following any argument in this thread, so I don't know the history here)
The surge resistor and PTC are still used in the voltage range to clamp via the two series MOVs to ground.
Once you have a clamp like for any main energy spike, then you don't need any major protection on the voltage input because of the attenuator. Maybe just a basic extra transistor clamp or something just in case.

A few pages back I said something about the volts-measurement path inside meters not going via the surge resistor+PTC and I got called out for it. The 101 is an example of a well regarded meter that does exactly that.  :)

The 10MOhms in that path will obviously attenuate a spike to the point where it can't damage the IC or it can be clamped by small components.

Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 03:26:27 am
EDIT: Here is my UT61E added to the right side:

That's three non-anecdotal variants!

Worse: You can see Uni-T deliberately planned to produce these unsafe variants after CAT certification by Intertek - the PCB has holes in it for different size fuse holders.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 29, 2021, 03:41:07 am
The 10MOhms in that path will obviously attenuate a spike to the point where it can't damage the IC or it can be clamped by small components.

Unless the resistors arc over. But there no way the input to the divider can go above the MOV clamping voltage, unless they fail, or you are talking about crazy small clamping times.
You design the 10M divider to easily handle the MOV clamping voltage and Bob's your uncle.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 29, 2021, 03:43:15 am
EDIT: Here is my UT61E added to the right side:
That's three non-anecdotal variants!
Worse: You can see Uni-T deliberately planned to produce these unsafe variants after CAT certification by Intertek - the PCB has holes in it for different size fuse holders.

To be fair, there is nothing wrong with that, provided that they are clearly marked and marketed as different model, but share the same PCB.
The fact that they are all labeled and sold as UT61E is troublesome.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 03:43:43 am
The surge resistor and PTC are still used in the voltage range to clamp via the two series MOVs to ground.
No argument.

What if the PTC heats up? Now the MOVs aren't doing much.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 29, 2021, 03:49:45 am
A few pages back I said something about the volts-measurement path inside meters not going via the surge resistor+PTC and I got called out for it. The 101 is an example of a well regarded meter that does exactly that.  :)

The Fluke 28 is another example. The 10M input resisotr is a ceramic jobbie, but in this case it does have an extra MOV on the other side of it.

(https://upload.wikimedia.org/wikipedia/commons/6/62/Fluke_28_Multimeter_Input_Protection.jpg)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 04:00:11 am
The Fluke 28 is another example.

 :)

My only point was that many meters have a path from the input jack to the IC that doesn't go via the PTC as shown in your input protection video.

If the PTC explodes during the first transient then your chances of surviving the second transient depend on the 10MOhm impedance in that path.

Edit: Yes, I know all about the surge resistor... all I'm saying is that the PTC could be out of action by eg. the user trying to measure mains AC on the Ohms range just before the lightning hits.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 29, 2021, 04:10:23 am
The Fluke 28 is another example. The 10M input resisotr is a ceramic jobbie, but in this case it does have an extra MOV on the other side of it.

These don't work quite the way you might think at first glance and you really need to look at schematics of meters (or at least I do) to see what really goes on.  I don't have a 28 schematic, but here's a what I think is a similar setup from an 87V/AN.  That first ceramic resistor Z2 is a 1M and is the sense resistor for ohms and some other stuff, the voltage and mV circuit actually does go through the PTC and surge resistor, the '10M' voltage divider resistor (Z1 in the diagram) is the one further away in your picture.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1284874;image)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 10:58:44 am
The surge resistor and PTC are still used in the voltage range to clamp via the two series MOVs to ground.
No argument.

What if the PTC heats up? Now the MOVs aren't doing much.

Sure they do.  They continue to clamp the voltage and provide the majority of the return path.   Now if you select one of the functions that engages the low voltage clamps, then the MOVs are basically removed.     

My only point was that many meters have a path from the input jack to the IC that doesn't go via the PTC as shown in your input protection video.

Actually your original comments were quite clear:

The PTCs aren't on the "voltage measurement" part of a multimeter circuit, they're on the much lower-impedance "ohms/continuity/etc" part of the circuit.

I haven't looked closely at this particular Uni-T but generally multimeters have a separate 10MOhm voltage input and a 10kOhm+PTC resistance/continuity input.

You offered the Fluke 101 as an example and I suggested you actually test it by removing the PTC from the circuit and reporting your findings: 
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg3717439/#msg3717439 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg3717439/#msg3717439)

With you now back-pedaling on your original statements and suggesting your point was something completely different I am curious:

A) You removed the PTC and found the 101 could no longer read AC and/or DC voltages? 
B)  You removed the PTC and found the 101 could still read AC and/or DC voltages but you don't want me to eat too much crow?
C) You want to continue to believe your original statements and are concerned they are wrong?  (burying your head in the sand rather than confronting it)
D) You lack the soldering skills to lift one pin or the 101 costs too much and you are concerned about damaging it?
E) You're too lazy and can't be bothered to test your theory?
Title: Re: UNI-T UT61E+ vs UT161E
Post by: AndrewBCN on September 29, 2021, 11:04:17 am

Which "UT61E" do you claim is certified? Which one do you think you'll get for 75 Euros? Better cross your fingers when you order...


The UT61E has been discontinued, so your entire argument is moot.

Oh, and just a note: as usual, you post pictures from others without attribution or mention of their origin. That picture of two different UT61E DMMs is by user Nisei and comes from this thread:
https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/1000/ (https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/1000/)

He clearly mentions that these are two different models of the UT61E.
Title: Re: Handheld meter robustness testing
Post by: HKJ on September 29, 2021, 11:19:09 am
Meters often has 3 paths from the V input terminal:

1) The 10Mohm path, it do not really need a MOV/PTC protection, but often share the protection from 2)
2) A lower impedance path (Typical for mV/ohm/capacity/etc), on better meters it is protected with a MOV/PTC combination (Not all meters has this path, but most has).
3) Current output for ohm and capacity, it is always protected with a PTC and on better meters also with a MOV. The MOV may not do anything when the range is selected, but protect the rotary switch when not selected.

I have written some more about multimeter input protection here: https://lygte-info.dk/info/DMMDesignProtection%20UK.html (https://lygte-info.dk/info/DMMDesignProtection%20UK.html)
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 29, 2021, 11:19:32 am
...
A) You removed the PTC and found the 101 could no longer read AC and/or DC voltages? 
B)  You removed the PTC and found the 101 could still read AC and/or DC voltages but you don't want me to eat too much crow?
C) You want to continue to believe your original statements and are concerned they are wrong? 
D) Lack the soldering skills to lift one pin or the 101 costs too much and you are concerned about damaging it?
E) You're too lazy and can't be bothered to test your theory?

Joe, you are assuming Fungus actually owns or has access to a Fluke 101. It's not that he is too lazy to test his theories, it's just that he can't. He really is the perfect armchair expert on DMMs that he has never even seen in person, much less taken apart.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 11:31:18 am
...
A) You removed the PTC and found the 101 could no longer read AC and/or DC voltages? 
B)  You removed the PTC and found the 101 could still read AC and/or DC voltages but you don't want me to eat too much crow?
C) You want to continue to believe your original statements and are concerned they are wrong? 
D) Lack the soldering skills to lift one pin or the 101 costs too much and you are concerned about damaging it?
E) You're too lazy and can't be bothered to test your theory?

Joe, you are assuming Fungus actually owns or has access to a Fluke 101. It's not that he is too lazy to test his theories, it's just that he can't. He really is the perfect armchair expert on DMMs that he has never even seen in person, much less taken apart.

You are assuming I am clueless on how to use a simple search engine.   Nice title change BTW.  Are we 12?   

How many Fluke meters do you own?  3 or so as I recall?

Five! (101, 187, 27FM, 37, 8060A)

Brymens? Only one!  :)

Referring to your recent comment:
Quote
The UT61E has been discontinued, so your entire argument is moot.
In France, does the word discontinued mean something is no longer available for purchase?   Or are you just trolling him? 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 29, 2021, 01:09:53 pm
...
But then you have companies like Uni-T that have a reputation for changing and omitting parts in models on a whim.
...

That's anecdotal, and even though it matters for a company's reputation or "vibes", objectively you would have to comparatively test to see how it affects the product's performance or safety.

Fungus posted this before, two UT-61E's.
I don't need a compartive test to tell me that one lacks all the MOV's and has smaller and lower rated fuses than the other.
EDIT: Here is my UT61E added to the right side:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1284730;image)

And there are other examples of Uni-T meters doing this. I've even had it myself were a meter I have differs a lot from one someone else has.

The discussion evolves around safety and certifications.  I don't know what the pass/fail criteria is for safety, only what I was told from two different companies that had very different interpretations.   I assume all three flavors have been certified for use in CAT III 600 or what ever they are marked for.  Is the cert worth anything?    Personally, I have bad vibes about the whole process.   :-DD
In fairness, the two meters to the right were never subjected to testing as AndrewBCN pointed out. Also, Dave was an earlier production model.

Sure, this does not instill confidence but I have a BM857 that is quite different than the currently sold versions as well - my model is from 2002 and has no independent certification markings. It can happen to anyone, really.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 29, 2021, 01:46:55 pm
...
But then you have companies like Uni-T that have a reputation for changing and omitting parts in models on a whim.
...

That's anecdotal, and even though it matters for a company's reputation or "vibes", objectively you would have to comparatively test to see how it affects the product's performance or safety.

Fungus posted this before, two UT-61E's.
I don't need a compartive test to tell me that one lacks all the MOV's and has smaller and lower rated fuses than the other.
EDIT: Here is my UT61E added to the right side:

...

And there are other examples of Uni-T meters doing this. I've even had it myself were a meter I have differs a lot from one someone else has.

I am not sure what your point is exactly. UNI-T is certainly not the only manufacturer that changes the PCB of a product during its lifecycle, or that populates the PCB with different components from one production batch to another.

Also the pictures of the discontinued UT61E that Fungus posted are from another EEVblog forum member Nisei, who duly noted (as can be seen on the PCB silk screen) that the two UT61E DMMs that he owns are different variants of the UT61E - the model on the left is a UT61E-GS and indeed it has better input protection and larger fuses.

Finally, what I was pointing out is that UNI-T again offers the UT61E+ in two different variants, the standard UT61E+ (which Joe is testing these days) and the Intertek-certified UT161E which costs only 2~3€ more. Whether they differ internally in terms of fuses and input protection is the question, and referring to 3~4 years old pictures of a different, discontinued model seems to me a bit irrelevant and a distraction.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 29, 2021, 04:44:36 pm
[...
Referring to your recent comment:
Quote
The UT61E has been discontinued, so your entire argument is moot.
In France, does the word discontinued mean something is no longer available for purchase?   Or are you just trolling him? 
In France, discontinued means exactly the same as in any part of the US or the UK:
discontinued
adjective
(of a product) no longer available or produced.

In any case, why bring a discontinued product with various versions into the discussion, when my comment was about the UT61E+ and its Intertek-certified version the UT161E and the negligible price difference between these two?
Title: Re: UNI-T UT61E+ vs UT161E
Post by: Fungus on September 29, 2021, 04:51:53 pm
The UT61E has been discontinued, so your entire argument is moot.

Huh? I can buy one right now from the Uni-T store on AliExpress.  :-//

https://www.aliexpress.com/item/33006341055.html (https://www.aliexpress.com/item/33006341055.html)

Oh, and just a note: as usual, you post pictures from others without attribution or mention of their origin. That picture of two different UT61E DMMs is by user Nisei and comes from this thread:

Huh? The link to Nisei's post is right underneath the picture I posted.  :-//

(...where it says "Ref:")

Joe, you are assuming Fungus actually owns or has access to a Fluke 101.  He really is the perfect armchair expert on DMMs that he has never even seen in person, much less taken apart.

That's three for three. Maybe you should take a break from posting.  :-//

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 29, 2021, 04:57:20 pm
I am not sure what your point is exactly. UNI-T is certainly not the only manufacturer that changes the PCB of a product during its lifecycle, or that populates the PCB with different components from one production batch to another.
 referring to 3~4 years old pictures of a different, discontinued model seems to me a bit irrelevant and a distraction.

Your dismissive hand-waving is a worthy performance.  UNI-T should retain you.  But here is what I think happened:

1) At some point UNI-T, for whatever reason, had to actually produce a compliant meter and the TUV wasn't going to stand for any bullshit, so they added a whole pile of protection to the front end, upgraded the fuses and most importantly, reduced the claimed CAT ratings to CAT III/300 and CAT II/600--mind you those aren't unreasonable for an 'at-home' meter. 

2) Subsequently, UNI-T also released a version lacking a good portion of that protection and without certification, but printed higher CAT III/1000V and CAT IV/600v 'ratings' on the front.  They did label the fused current circuits as 250V, but whether that is allowed or not might be one of those things that jqs was referring to when he said different companies interpret the standards differently.  I think it defeats one of the major points of having CAT ratings in the first place.

What the current 'certified' version has in it's guts, I don't know.  Given the labelling on the front, it's pretty clear they didn't put 1000V fuses in it.  Perhaps they persuaded Intertek in China to adopt their interpretation of the CAT ratings standard.  But it is pretty clear that they are using different approaches depending on who is watching.  And that raises two disturbing non-technical conclusions, which are 1) UNI-T is untrustworthy, and 2) CAT ratings, even when 'certified', may not mean the same thing when comparing between manufacturers. 

So as a point of comparison, take the modest Fluke 115/116/117 series, which just have a CAT III/600V rating and no CAT IV.  They have 1000V fuses (except the 116 which has no fuse) and can withstand 600V (not just a transient) on any range or input combination without damage--and probably a lot more.  You'll also see that the 115 went all the way to the 12kV jqsTM test without failing.  That is in line with my expectations of a CAT-rated device--and is what some companies deliver when they print a CAT-rating on their meter.

If the standards can legitimately be interpreted to allow what you get with the UT61E, certified or not, then those standards themselves are not useful to me as a point of comparison.  Here are the front sides of the UT-61E-GS and the 'regular' UT-61E.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1285336;image)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 05:10:39 pm
[...
Referring to your recent comment:
Quote
The UT61E has been discontinued, so your entire argument is moot.
In France, does the word discontinued mean something is no longer available for purchase?   Or are you just trolling him? 
In France, discontinued means exactly the same as in any part of the US or the UK:
discontinued
adjective
(of a product) no longer available or produced.

In any case, why bring a discontinued product with various versions into the discussion, when my comment was about the UT61E+ and its Intertek-certified version the UT161E and the negligible price difference between these two?

While the manufacturer may have discontinued the product,  it's certainly still available for purchase.  People can still choose it over other products.     

I often ask why people continue to discuss safety in a thread that has nothing to do with it. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 05:18:29 pm
In any case, why bring a discontinued product with various versions into the discussion, when my comment was about the UT61E+ and its Intertek-certified version the UT161E and the negligible price difference between these two?

The discussion wasn't about availability of the UT61E, it was about the value of an Intertek certificate.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 29, 2021, 05:43:12 pm

A) You removed the PTC and found the 101 could no longer read AC and/or DC voltages?
B)  You removed the PTC and found the 101 could still read AC and/or DC voltages but you don't want me to eat too much crow?
C) You want to continue to believe your original statements and are concerned they are wrong?  (burying your head in the sand rather than confronting it)
D) You lack the soldering skills to lift one pin or the 101 costs too much and you are concerned about damaging it?
E) You're too lazy and can't be bothered to test your theory?
F) I've burned myself too many times trying to solder and am scared to pick that thing up!!

Burning yourself with a soldering iron is nothing to be ashamed of.   :-DD 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 29, 2021, 05:56:54 pm
I found another meter that has a separate path for voltage that doesn't go via the surge resistor/PTC.
See, I'm not crazy!  :) :) :)

Crazy, no, but you may have jumped to a conclusion a bit early.

Have a look at the input diagram that I posted in response to Dave, then note that the 7 resistors you are referring to are 143K, so they add up to 1M.  Without tracing it out or finding a schematic I can't be 100% sure of the configuration, but the 87V/AN schematic I posted is fairly typical for contemporary Fluke designs.  As for others, it will be driven by the requirements of the chipset that they use.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 06:09:31 pm
Have a look at the input diagram that I posted in response to Dave, then note that the 7 resistors you are referring to are 143K, so they add up to 1M.  Without tracing it out or finding a schematic I can't be 100% sure of the configuration, but the 87V/AN schematic I posted is fairly typical for contemporary Fluke designs.  As for others, it will be driven by the requirements of the chipset that they use.

Maybe that path is something to do with the IEC61010 requirement for the meter to still show hazardous voltages even if it's damaged. It could go directly to a comparator and show an indicator on screen or something like that. It would work in all ranges with no CPU required.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 29, 2021, 06:14:22 pm

A) You removed the PTC and found the 101 could no longer read AC and/or DC voltages?
B)  You removed the PTC and found the 101 could still read AC and/or DC voltages but you don't want me to eat too much crow?
C) You want to continue to believe your original statements and are concerned they are wrong?  (burying your head in the sand rather than confronting it)
D) You lack the soldering skills to lift one pin or the 101 costs too much and you are concerned about damaging it?
E) You're too lazy and can't be bothered to test your theory?
F) I've burned myself too many times trying to solder and am scared to pick that thing up!!

Burning yourself with a soldering iron is nothing to be ashamed of.   :-DD

G) You're in gloat mode and sound fairly sure of yourself so I'm guessing I'm wrong.

I don't mind being wrong, it's an excellent way to learn. I wish I could be wrong more often.

Right now I'm trying to think what it would be for if it's not for voltage measurement.

Crazy, no, but you may have jumped to a conclusion a bit early.

Have a look at the input diagram that I posted in response to Dave, then note that the 7 resistors you are referring to are 143K, so they add up to 1M.

OK, I wasn't paying attention here but I've got other meters with a resistor chain like that and they add up to 10M. I've measured it.

That's why I'm confused - there may still be meters that measure voltage that way even if the 101 doesn't.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 29, 2021, 06:28:49 pm
Maybe that path is something to do with the IEC61010 requirement for the meter to still show hazardous voltages even if it's damaged. It could go directly to a comparator and show an indicator on screen or something like that. It would work in all ranges with no CPU required.

I don't think so.  I think the best way to comply with that requirement is to not let the meter become damaged!  These sections seem to be for ohms/capacitance/maybe other stuff.  If you look at meter designs, it is possible to construct an ohms source that is simply impervious to external voltage up to 1kV+ using just a diode and three transistors.  Then you use the normal high-impedance voltage circuit to measure.  However, if you want a meter that does capacitance, etcyou need to do things differently and these modern designs seem to rely on this 1M leg plus PTC protection of the other circuit.  I'm not saying they're all the same, just that the ones I have seen sort of all look like this.  I think if you pull one of those resistors, you'll see that the voltage ranges still work but OHM/CAP/DIODE will not.  If you pull the PTC, you likely won't get any voltage indication.

Right now I'm trying to think what it would be for if it's not for voltage measurement.

OK, I wasn't paying attention here but I've got other meters with a resistor chain like that and they add up to 10M. I've measured it.

Well, it is for voltage measurement, just not in the voltage ranges.

Other designs may work differently.  Were the ones with 10M in that spot Fluke or som'n else?
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 29, 2021, 06:46:57 pm
[...] UNI-T is certainly not the only manufacturer that changes the PCB of a product during its lifecycle, or that populates the PCB with different components from one production batch to another.

UT61E there are least 15 PC board revisions! Did you end up with the kindergarten or junior-high version? Earlier ones were extra junky and ended up in landfill.
It's a bit ridiculous and I don't get a sense they know what they are doing. Seem to sell prototype builds off with fake regulatory claims and as they learn, for years.
And it's over $0.25 worth of parts savings for the boss's new Lambo  :-DD
The two schematics one has MOV's, they don't use Rev. #'s and SG4 (4th MOV)  at the current-shunts, appears useless.

Rev. 13(GS) has 4 MOV's, 3 PTC's, 600V fuses, rating Cat. III 300V, Cat. II 600V
Rev. 12  has 4 MOV's, 3 PTC's, 600V fuses, rating Cat. III 300V, Cat. II 600V
Rev. 9C  no MOV's, 3 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V;  SOT89 clamps
Rev. 9A  no MOV's, 2 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V
Rev. 8    no MOV's, 2 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V; SOT23 clamps

UT61E+
Rev. 3 has 3 MOV's, 4 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V
Rev. 2 looks the same, blue pcb
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 29, 2021, 09:37:25 pm
While the manufacturer may have discontinued the product,  it's certainly still available for purchase.  People can still choose it over other products.     

I never wrote that it was not available for purchase, I wrote that it was discontinued.

Clearly UNI-T have discontinued the UT61E (all variants): it states as much on their website. And I guess just like any discontinued product, it will still be available at various resellers "while stocks last".

In any case, it is completely irrelevant to what I posted, which was about the UT61E+ which you are testing these days, and the externally identical but Intertek-certified UT161E, which costs 2~3€ more.

Fungus made it a point to show a 4-year old picture of two different variants of the old UT61E and pointed the obvious: that they had different components. How is that relevant to the UT61E+ and its Intertek-certified version the UT161E?  :palm:
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 29, 2021, 10:41:09 pm
How is that relevant to the UT61E+ and its Intertek-certified version the UT161E?

OK, I see that the meter you referred to as 'externally identical' is actually the UT161E, which appears to me to be an entirely different meter.  So my fault for misreading and yours for saying they look the same or that the 161E is somehow a 'version' of the 61E.  It is, in fact labelled CAT III/1000V and CAT IV/600V with fuses listed as 1000V, which I'll presume reflects what is inside.  So we probably won't be able to proclaim noncompliance just by looking at it, or at least not as easily.  This appears to also be a more expensive meter, as you'd expect, but it is indeed available on Aliexpress for $73 shipped.  So if you like bargains, order one up and take it apart to show us its guts!

Edit: Never mind all that!  I see which meters are being referred to now... :palm:
Title: Re: Handheld meter robustness testing
Post by: floobydust on September 29, 2021, 11:01:51 pm
Uni-T is doing the PCB copy'n'paste between UT61E+ and UT161E. I see the larger fuses and PTC's, PTC's moved slightly but nothing significant.
Looks like they want to charge a premium for a real 61010 product. I'll bet the BBQ lighter still makes it crash lol.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 12:11:57 am
G) You're in gloat mode and sound fairly sure of yourself so I'm guessing I'm wrong.

I don't mind being wrong, it's an excellent way to learn. I wish I could be wrong more often.

I suggest taking the opportunity to try it for your self.  If it doesn't work as your first suggested, trace out the front end.  Learn where you made the mistake. 

Right now I'm trying to think what it would be for if it's not for voltage measurement.

It's easy enough to break the other circuit and see what the effects are.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 12:19:08 am
While the manufacturer may have discontinued the product,  it's certainly still available for purchase.  People can still choose it over other products.     

I never wrote that it was not available for purchase, I wrote that it was discontinued.

I never suggested otherwise.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 12:28:17 am
Uni-T is doing the PCB copy'n'paste between UT61E+ and UT161E. I see the larger fuses and PTC's, PTC's moved slightly but nothing significant.
Looks like they want to charge a premium for a real 61010 product. I'll bet the BBQ lighter still makes it crash lol.

Maybe the BBQ lighter would damage them both.  Depending how the 61E+ holds up, I may have another look. 
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 30, 2021, 12:30:16 am
[...] UNI-T is certainly not the only manufacturer that changes the PCB of a product during its lifecycle, or that populates the PCB with different components from one production batch to another.

UT61E there are least 15 PC board revisions! Did you end up with the kindergarten or junior-high version? Earlier ones were extra junky and ended up in landfill.
It's a bit ridiculous and I don't get a sense they know what they are doing. Seem to sell prototype builds off with fake regulatory claims and as they learn, for years.
And it's over $0.25 worth of parts savings for the boss's new Lambo  :-DD
The two schematics one has MOV's, they don't use Rev. #'s and SG4 (4th MOV)  at the current-shunts, appears useless.

Rev. 13(GS) has 4 MOV's, 3 PTC's, 600V fuses, rating Cat. III 300V, Cat. II 600V
Rev. 12  has 4 MOV's, 3 PTC's, 600V fuses, rating Cat. III 300V, Cat. II 600V
Rev. 9C  no MOV's, 3 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V;  SOT89 clamps
Rev. 9A  no MOV's, 2 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V
Rev. 8    no MOV's, 2 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V; SOT23 clamps

UT61E+
Rev. 3 has 3 MOV's, 4 PTC's, 250V fuses, rating Cat. III 1,000V, Cat. IV 600V
Rev. 2 looks the same, blue pcb

Where did you get the Uni-T schematics from?
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 30, 2021, 12:37:41 am
Also the pictures of the discontinued UT61E that Fungus posted are from another EEVblog forum member Nisei, who duly noted (as can be seen on the PCB silk screen) that the two UT61E DMMs that he owns are different variants of the UT61E - the model on the left is a UT61E-GS and indeed it has better input protection and larger fuses.

Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 30, 2021, 12:42:50 am
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".

My reply #4203 has them.  The meter is still labelled UT61E, but has the "GS" mark and has different CAT ratings.
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on September 30, 2021, 12:45:09 am
Fungus post #4172 has a pic of the meter opened up too
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 30, 2021, 01:31:53 am
I often ask why people continue to discuss safety in a thread that has nothing to do with it.

One would need to reread the entire thread to see how that seeped in, but I suspect the similarities of your test transient levels to the ones specified for the CAT ratings are one factor.

Anyhow, by now I agree with you, if you are referring to safety as meters exploding or arc-flash type concerns.  My concerns are similar to what you have said about wanting meters to not die during normal, non-dangerous bench or other use.  Transients are one way to kill them of course, but accidental overvoltage is another.  I had one set of expectations about what a CAT-rating would mean about this, specifically that a meter with a CAT rating for any voltage--like a bench meter rated CAT I/1000V--would endure 1000VAC or 1000VDC on any range or input selection without damage.  There's also the expectation that after the transient tests, the meter works.  If those expectations on my part are wrong and the CAT ratings don't indicate performance in that regard across the board, or if different manufacturers have different standards regarding these issues, then the CAT ratings themselves are meaningless to me and of questionable value to anyone else, IMO. 

If anyone wants to comment on my assertion that a CAT x/1000V meter should withstand a full 1000V on any input setting or jack, I can see about setting up a test.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 30, 2021, 01:34:55 am
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".

My reply #4203 has them.  The meter is still labelled UT61E, but has the "GS" mark and has different CAT ratings.

That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs and ratings.
Why would anyone trust a company that sells the exact same model number meter in different markets with different safety/protection components?
At the very least give it another model number.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 30, 2021, 01:44:03 am
That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs.

Yes, I suppose that's true if the '-GS' is just an internal designation and the model that it was marketed as is just UT61E.  So under the jurisdiction of the TUV, they sold one 'UT61E' with protection and lowered CAT ratings, elsewhere they depopulated the protection and increased the purported CAT ratings.  I think other companies in other areas may do similar things between markets, but CAT ratings are a globally harmonized standard (or so I thought) so it does seem quite slippery of them.
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on September 30, 2021, 01:46:38 am
The Uni T equivalent of the Fluke Ex series meters  :-DD
Title: Re: Handheld meter robustness testing
Post by: EEVblog on September 30, 2021, 01:49:42 am
That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs.
Yes, I suppose that's true if the '-GS' is just an internal designation and the model that it was marketed as is just UT61E.  So under the jurisdiction of the TUV, they sold one 'UT61E' with protection and lowered CAT ratings, elsewhere they depopulated the protection and increased the purported CAT ratings.  I think other companies in other areas may do similar things between markets, but CAT ratings are a globally harmonized standard (or so I thought) so it does seem quite slippery of them.

With my Brymen meters that I resell under the EEVblog branding I have to have them the exact same model number BM235/BM786 and the Brymen name, otherwise if I change it they would of had to have got it entirely UL certified again which is of course lengthy and expensive process. I can't just whack another model number on it and use the UL logo and certificate for physically the exact same meter, it's that strict.
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on September 30, 2021, 01:53:42 am

With my Brymen meters that I resell under the EEVblog branding I have to have them the exact same model number BM235/BM786 and the Brymen name, otherwise if I change it they would of had to have got it entirely UL certified again which is of course lengthy and expensive process. I can't just whack another model number on it and use the UL logo and certificate for physically the exact same meter, it's that strict.

Did the 121GW need any sort of recertification with board revisions?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 01:59:27 am
Especialy the low energy spikes will be hard to find any info about, because they don't cause imediate failure so it would be difficult to asess what would be the most common but already harmful energy and voltage level.But I think something well within Joes generators range.

You're going to have to define and quantify 'low energy' and fully specify the circuit characteristics and other test conditions for any further discussion to have meaning.  I wouldn't call the jqsTM transients 'low energy'.

I've been meaning to respond to your comment.   I suspect many people share your thoughts which is partly why some relate them to safety and AC mains testing.   

I want to be clear that when I talk about my transients being low energy, I am making a relative comparison with the  61010 standards that I had loosely based them from.   Again, the standards call for a hybrid, or combo generator.   They specify an open circuit voltage wave form with a 1.2us rise and 50us FWHH  (1.2/50).    Consider that I have a faster rise and a longer delay.  This all came from my initial testing of the very first $50 meters.  I started out with a much narrower transient and worked my way up.  I also started out using much lower energy levels.   The initial levels were so low, I couldn't damage a meter.   By the time I started to test the $50 meters, I think I had settled on a 50us full width (not FWHH) at 10J.   When I decided to design a programmable generator, I doubled the energy to roughly 20J and settled on the 100us FWHH.  I also decided on a peak of 6kV where the Amprobe AM510 had been damaged during the $50 shootout. 

It may seem like my transients far exceed the standards, after they take twice as long to decay and have the same source impedance.   Makes sense until considering the current.   
 
The following was just the first TVS from Digikey. 
https://media.digikey.com/pdf/Data%20Sheets/NextGen%20Components%20PDFs/SM12.pdf     

Notice the text  "Peak Pulse Power per (8/20μs): 350 Watts"   That 8/20us defines the short circuit current waveform called out in the 61010 standard.   There are two waveforms, hence the name combo or hybrid generator. 

I use a 2 ohm source, so if I have a 1kV peak, the current will be 1kV/2 or 500A.  Where the combo generator has a 20us Full Width Half Height, mine may only have a ns.   :-DD   No, it's not  that narrow but 20J isn't much.   I made a recent video showing what the current looked like through a meter.  Not much happened as expected.   

So maybe this will help a few of you understand.   Consider the attached data taken with my scope.   The scope's settings were kept the same throughout the test.  Channel 1 (gold) is looking at the voltage.  Channel 2 (pink) is the current.   

Tran1 starts with an open circuit.  Note that there is no current draw and the voltage is a bit shy of a kV (using my home made 100x probes again).   At 20us / div, half way up measures roughly 100us across.   No surprise.

Tran2, I have added a small load.  The peak voltage is still roughly the same but we can see some current flowing.  Notice now that the voltage FWHH is roughly  30us.   

Tran3, I have increased the load and we can see the peak voltage has dropped.  Where did the voltage go??  It's dropped across the generator's internal 2 ohm source! Notice that the current's FWHH is now only 10us or so.  Remember, the standard called for 20us with a short.  I'm sure a few of you can guess the effects of further increasing the load.

Again, the goal was never to make these meters explode like you will find in Fluke's test lab videos.  That should have been obvious by simply comparing the physical size of their 19" rack mounted Haefely compared with my tiny desktop setup.   Normally the meters will not break down and all that energy is dissipated in the generator's internal coupling network.  The 20J may be overkill but all you safety experts posting here already know where that number came from.   I wanted at much as possible but still work with a minimal risk.

You may not agree but hopefully you at least now have some understanding why I will continue to call my transients low energy.   

****
Rough reading in a few places.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 30, 2021, 03:54:04 am
The 20J may be overkill but all you safety experts posting here already know where that number came from. 

Hmmm.  Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?  :-DD

Quote
You may not agree but hopefully you at least now have some understanding why I will continue to call my transients low energy.

Thanks for the detailed explanation.  Low is a relative term, of course, and relative to MOV ratings, IEC transients, etc, 20J is obviously much lower.  The comment I responded to was talking about damage to semiconductors, etc and there 20J  will pop the lid on quite a few devices.   I think the low energy events he was referring to are the sorts of noise, ESD or spikes that might get through normal filtering for reasons other than that they overwhelm the protection systems by simply exceeding their voltage or energy limitations.  Piezo igniters and 220MHz RF come to mind....

With that in mind, given the mayhem your jqs IEC LiteTM transients cause, it is difficult for me to see how some of these units could emerge from the full mains-connected IEC transient test unscathed, unless the criteria being applied are just that the device not explode or trip the mains limiting. 


Title: Re: Handheld meter robustness testing
Post by: tautech on September 30, 2021, 04:10:46 am
Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?  :-DD
20J is a baby fence unit these days now energisers of 60J are available:
https://pel.co.nz/en-nz/node/11974
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 30, 2021, 08:19:35 am
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".

My reply #4203 has them.  The meter is still labelled UT61E, but has the "GS" mark and has different CAT ratings.

That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs and ratings.
Why would anyone trust a company that sells the exact same model number meter in different markets with different safety/protection components?
At the very least give it another model number.
They were indeed idiots when doing this to the UT61E but, in all fairness, that is exactly what they are doing now with their new UT61E+ / UT161E differentiation. Perhaps an attempt to redeem themselves? Even still, this does not excuse slapping false ratings in several of their meters.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on September 30, 2021, 08:41:21 am
With that in mind, given the mayhem your jqs IEC LiteTM transients cause, it is difficult for me to see how some of these units could emerge from the full mains-connected IEC transient test unscathed, unless the criteria being applied are just that the device not explode or trip the mains limiting.
In my interpretation of the 61010 is that the meter is not expected to survive the transients. The fact Fluke and others are not screaming at the top of their lungs about this is an indication I am not alone in my interpretation. Sure, Fluke has some spectacular videos of exploding meters, but they talk about containing the energy of the damage inside the housing to avoid high speed ejection of material and quenching arc flash.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 30, 2021, 09:50:15 am
Uni-T is doing the PCB copy'n'paste between UT61E+ and UT161E. I see the larger fuses and PTC's, PTC's moved slightly but nothing significant.
Looks like they want to charge a premium for a real 61010 product. I'll bet the BBQ lighter still makes it crash lol.
You can bet whatever you want, but thanks for digging out a picture of the internals of the UT61E+ and the externally identical, but internally quite different, intertek-certified UT161E (from a Russian forum?).

So UNI-T charge a 3€ "premium" for the larger fuses and PTCs, and proper independent testing and certification for the UT161E, which as you well know, has a cost.

I earlier wrote that for the extra 3€, I would rather buy the Intertek-certified UT161E rather than the UT61E+ that Joe is testing these days. The picture you posted just confirmed this.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on September 30, 2021, 10:21:11 am
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".

My reply #4203 has them.  The meter is still labelled UT61E, but has the "GS" mark and has different CAT ratings.

That's my point. The model number is exactly the same, yet the meter differs greatly in it's safety specs and ratings.
Why would anyone trust a company that sells the exact same model number meter in different markets with different safety/protection components?
At the very least give it another model number.

The "GS" designation for the UT61E apparently stood for "German Safety". Here is a link to a reseller in Germany that specifically sells the UT61E GS.

https://www.pinsonne-elektronik.de/pi2/pd58.html (https://www.pinsonne-elektronik.de/pi2/pd58.html)

From that same page you can download the user manual (in English) for the UT61E GS, it has the safety standards compliance on page 6 and the GS mark explained on page 9.

I have no idea if the discontinued UT61E GS was ever sold in any other country than Germany (and I couldn't care less).

The Intertek-certified UT161E is available internationally, as I wrote before for a negligible premium over the non-certified, smaller fuses and PTCs UT61E+ which Joe is testing these days.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 30, 2021, 10:32:19 am
So UNI-T charge a 3€ "premium" for the larger fuses and PTCs, and proper independent testing and certification for the UT161E, which as you well know, has a cost.

No, the UT161E is far more expensive, about double the price of the UT61E.

It still has the stupid transistor tester though. I'd never own one because of that "feature". I'd have to do a facepalm every time I turned the selector past that position on the dial.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 12:44:48 pm
It still has the stupid transistor tester though. I'd never own one because of that "feature". I'd have to do a facepalm every time I turned the selector past that position on the dial.

You should consider getting this as it seems it would fit your skill set very well.

https://www.amazon.com/Fisher-Price-Laugh-Learn-Puppys-Remote/dp/B014KEEFO8 (https://www.amazon.com/Fisher-Price-Laugh-Learn-Puppys-Remote/dp/B014KEEFO8)

I doubt the group will think any less of your skills if that helps.    :-DD   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 01:20:16 pm
I often ask why people continue to discuss safety in a thread that has nothing to do with it.

One would need to reread the entire thread to see how that seeped in, but I suspect the similarities of your test transient levels to the ones specified for the CAT ratings are one factor.

Anyhow, by now I agree with you, if you are referring to safety as meters exploding or arc-flash type concerns.  My concerns are similar to what you have said about wanting meters to not die during normal, non-dangerous bench or other use.  Transients are one way to kill them of course, but accidental overvoltage is another.  I had one set of expectations about what a CAT-rating would mean about this, specifically that a meter with a CAT rating for any voltage--like a bench meter rated CAT I/1000V--would endure 1000VAC or 1000VDC on any range or input selection without damage. There's also the expectation that after the transient tests, the meter works.  If those expectations on my part are wrong and the CAT ratings don't indicate performance in that regard across the board, or if different manufacturers have different standards regarding these issues, then the CAT ratings themselves are meaningless to me and of questionable value to anyone else, IMO. 

If anyone wants to comment on my assertion that a CAT x/1000V meter should withstand a full 1000V on any input setting or jack, I can see about setting up a test.


We have.   If you take the time to go over it,  feel free to then let me know if there is something you did not understand.   

I am all for YOU running a test like this.  I think if you want to light it up, you are going to have to use the meter incorrectly and turn the function switch with it live.  If you pick a meter that I have already and find it survives, maybe I can attempt to repeat it.   I have that one 121GW that was used for the majority of my destructive tests.  It has been certified.  I could toss that into the mix as well. 

Some of the smaller PTCs are only rated for 500V.  Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them....  Maybe....  Turn the dial, I suspect you will get a light show.

Well that doesn't sound very robust!  I don't know if that is a failure to meet a standard or not, but it seems like a basic expectation to me.  Every CAT labelled meter I currently have that isn't known junk should pass that test.  Some of them already have by accident.

Maybe start reading here.  Dave chimes in.  So do I. 
https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1580530/#msg1580530 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1580530/#msg1580530)

****
1kVDC with more than enough current to cause a major meltdown ready when you are. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 01:23:38 pm
Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?  :-DD
20J is a baby fence unit these days now energisers of 60J are available:
https://pel.co.nz/en-nz/node/11974

Don't take a whiz on that!   
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 30, 2021, 05:03:31 pm
Here's a genuine CAT III 300V certified meter which has been discussed somewhere in the middle thread. It has two resistor trails leading off before anything gets to the PTC. The R31/R30/R29/R28 chain is 10MOhms, the same as the impedance of the meter in volts mode. It's not the only meter I own that's like this, hence the silly ideas in my head.

I think the input circuit is clear enough in this photo:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286170;image)

I lifted up one leg of the PTC as joe suggested:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286176;image)

Guess what? It still measures volts perfectly!
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286182;image)

OK, maybe the Fluke 101 doesn't work that way (I should have looked at the resistor values before opening my mouth) but there's definitely some certifiable meters that do work that way.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on September 30, 2021, 06:29:49 pm
I earlier wrote that for the extra 3€, I would rather buy the Intertek-certified UT161E rather than the UT61E+ that Joe is testing these days. The picture you posted just confirmed this.

Well, regardless of whatever else we disagree about, now that I see the correct meters that you are referring to I'd have to agree with that.  They seem to have finally made an attempt to build up the 'certified' version to the standards they printed on the UT61E+ rather than have it certified down to a much lower level.  It even looks like they are using the actual Bussmann fuse.
Title: Re: Handheld meter robustness testing
Post by: tautech on September 30, 2021, 07:20:46 pm
Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?  :-DD
20J is a baby fence unit these days now energisers of 60J are available:
https://pel.co.nz/en-nz/node/11974

Don't take a whiz on that!
Hell no !
Pic below of a short from 2.5mm (12g) wire to a tree 1 mile from our 40J unit where the CLACK could be heard a couple hundy yds away.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 30, 2021, 11:20:16 pm
Here's a genuine CAT III 300V certified meter which has been discussed somewhere in the middle thread. It has two resistor trails leading off before anything gets to the PTC. The R31/R30/R29/R28 chain is 10MOhms, the same as the impedance of the meter in volts mode. It's not the only meter I own that's like this, hence the silly ideas in my head.

I think the input circuit is clear enough in this photo:
...
I lifted up one leg of the PTC as joe suggested:
...
Guess what? It still measures volts perfectly!
...

OK, maybe the Fluke 101 doesn't work that way (I should have looked at the resistor values before opening my mouth) but there's definitely some certifiable meters that do work that way.

As I said

Keep those stories coming.  We're here all night folks.

I'm having a moment, aren't I?
I suspect you have been looking at too many low end meters like the UNI-T,  ANENG....    Your statement about "...generally multimeters have a separate 10MOhm voltage input.." could be correct as I suspect there are more low end meters being introduced and sold.    We love our cheap, disposable products which drives the market and I just don't want to admit it. 

Just another cheap meter.   These don't surprise me but I'm interested in what your Fluke 101 does.   Now that you have had some practice with the soldering iron, time to lift one more pin. 

Quick search, looks like you died from that meter  :-DD
https://www.eevblog.com/forum/testgear/heads-up-cheap-multimeter-lidl-uk-(080218)/msg1429596/#msg1429596 (https://www.eevblog.com/forum/testgear/heads-up-cheap-multimeter-lidl-uk-(080218)/msg1429596/#msg1429596)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 01, 2021, 04:33:19 am
I am all for YOU running a test like this.  I think if you want to light it up, you are going to have to use the meter incorrectly and turn the function switch with it live.  If you pick a meter that I have already and find it survives, maybe I can attempt to repeat it.   I have that one 121GW that was used for the majority of my destructive tests.  It has been certified.  I could toss that into the mix as well. 

1kVDC with more than enough current to cause a major meltdown ready when you are.

OK, I finally got another project done after my parts went on a four day tour of North Dakota--so there's room on the bench.  Next projects are some calibrator overhauls, so just the perfect opportunity to test some meters.  Unfortunately, I discovered that I don't have all that much power, probably not even what the calibrator is supposed to have, so I'll have to look at that issue before I get too far.  I don't want to abuse the meters by switching ranges under power, just test them at max voltage on all ranges.  I'll leave exploding things to others for now.

First test was a Fluke 116.  You have tested a 115, I don't know if you have it still or how similar they are.  I gave it 600VDC and 600VAC/100Hz in all ranges, 10-15 seconds per range, then checked its calibration afterwards.  All good.  I did notice that when it clamps, it can clamp a lot more current than my calibrator can supply.  I had to use a different DC supply. For AC, I had to start at a lower voltage then work my way up as fast as I could push the buttons. 

The next victim was actually not a handheld, but an old Fluke 8842A bench meter.  No CAT rating, but it took the 1000VDC and 700VAC listed on the front panel without complaint, ohms range and all, but the calibrator started whining (literally) so I quit for the night.  I'm really not looking to blow that one up.

I can toast a Harbor Freight meter for giggles, but other than that I don't have a lot to throw at it right now.
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 01, 2021, 06:10:10 am
Just another cheap meter.   These don't surprise me but I'm interested in what your Fluke 101 does.

As pointed out: The resistor chain is only 1MOhm. I don't think it's going to be the voltage input based on that and your recent postings.

I'm more interested in the function of that circuit than simply confirming something that's already known - science doesn't advance that way. Corrrect procedure requires a theory before I barge in and do any experiments so I need to find time to sit down and trace out the 101 PCB as the next step.

PS: The Fluke 101 is a "cheap meter". For the  price of a Uni-T U61E I can get a Fluke 101 and an Aneng 870.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 09:31:53 am
Just another cheap meter.   These don't surprise me but I'm interested in what your Fluke 101 does.
..
I'm more interested in the function of that circuit than simply confirming something that's already known - science doesn't advance that way. Corrrect procedure requires a theory before I barge in and do any experiments so I need to find time to sit down and trace out the 101 PCB as the next step.

 :-DD :-DD :-DD
Lame, but that's alright.   

PS: The Fluke 101 is a "cheap meter". For the  price of a Uni-T U61E I can get a Fluke 101 and an Aneng 870.

I would have thought when I write use the word cheap,  generally people understood it was a shoddy product.  Another definition for cheap is low cost but I will typically write that out.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 10:03:35 am
...
I don't want to abuse the meters by switching ranges under power, just test them at max voltage on all ranges.  I'll leave exploding things to others for now.

First test was a Fluke 116.  You have tested a 115, I don't know if you have it still or how similar they are.  I gave it 600VDC and 600VAC/100Hz in all ranges, 10-15 seconds per range, then checked its calibration afterwards.  All good.  I did notice that when it clamps, it can clamp a lot more current than my calibrator can supply.  I had to use a different DC supply. For AC, I had to start at a lower voltage then work my way up as fast as I could push the buttons. 

The next victim was actually not a handheld, but an old Fluke 8842A bench meter.  No CAT rating, but it took the 1000VDC and 700VAC listed on the front panel without complaint, ohms range and all, but the calibrator started whining (literally) so I quit for the night.  I'm really not looking to blow that one up.

I can toast a Harbor Freight meter for giggles, but other than that I don't have a lot to throw at it right now.

When cold, I am expecting with a kV applied, the initial draw is somewhere around 1kV/2000ohms or 500mA.   Higher for some of the cheap meters.   I doubt many electronics hobbyist have that sort of power supply on hand.   I would think the use case was you touch the leads to the live source with the meter set to each function, except for the current.  Allowing a minute or so for the PTC to cool between tests.   Creeping up on the voltage would seem like a rare case.   

I have had meters become damaged with a 1kV transient. These would certainly fail with DC applied.  These are not in the same class as your 116. 

I have a very bad habit of changing functions live.  I do this with my bench meters as well as the handhelds.  I've written software to changes modes as part of a test.  Commonly, I will move from AC to DC.  Meters with LowZ would be interesting as that should get you enough of a path to form an arc if you switch it live.  Mostly I'm working below where I would be concerned with arcing the switch or relay contacts. 

****
A short experiment with a 5kohm resistor, 1kVDC source and an air gap (could be the DMMs switch)
https://youtu.be/bgz-pqg0rKo?t=1271
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 01, 2021, 12:55:28 pm
I got around to experimenting with my 101 as Joe suggested, here's the results:

I lifted up on leg of the surge resistor:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286800;image)

Meter now fails to measure voltage. The number on screen is a floating value that appears even if I connect only one probe to the live wire. The voltage hazard indicator doesn't light up:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286794;image)

Here it is back together and working again:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286806;image)

The resistor chain goes up to the selector and is connected across to the adjacent track when the switch is in the mV/Ohms/Capacitance/Hz modes. It isn't connected in  the VAC/VDC modes. That's my theory of it being used for hazardous voltage indication shot down in flames.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286812;image)

The back of the PCB showing the signal path. The signal jumps across the selector then heads off in the general direction of the IC. It goes into another via and I lost it there. There's no corresponding via on the front of the PCB so it must go into an inner layer.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286818;image)

Now I need a new theory. The signal isn't used on either of the main voltage ranges and it's not for the hazardous voltage indicator.  ???
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 01:25:48 pm
Nice job sir.   Do you have the tools/skills needed to remove one of the resistors that make up the chain R8-R2?   If so, I would just reattach R20 and pull one of the other and see which functions no longer work. 
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on October 01, 2021, 02:15:59 pm
Now I need a new theory. The signal isn't used on either of the main voltage ranges and it's not for the hazardous voltage indicator.  ???

What do you mean another theory? It is used here like you said:
The resistor chain goes up to the selector and is connected across to the adjacent track when the switch is in the mV/Ohms/Capacitance/Hz modes.

There must separate path injecting current into DUT for resistance and capacitance, and this composite 1 MOhm resistor is measurement path for these ranges. There will be transistor clamp after it somewhere before going into DMM chip. ...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 02:43:38 pm
People learn in various ways.  Some, like myself are very hands on.   I have found that seeing and experiencing how things work first hand can improve my understanding beyond just reading a book.    In this case, we are talking about removing a couple of resistors.  The idea would be for Fungus to prove what is happening to themselves,  not the rest of the internet world.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 01, 2021, 03:19:09 pm
When cold, I am expecting with a kV applied, the initial draw is somewhere around 1kV/2000ohms or 500mA.   Higher for some of the cheap meters.   I doubt many electronics hobbyist have that sort of power supply on hand.   I would think the use case was you touch the leads to the live source with the meter set to each function, except for the current.  Allowing a minute or so for the PTC to cool between tests.   Creeping up on the voltage would seem like a rare case.

The 116 appears to be ~3k initially on Lo-Z ranges.  My DC supply does sag a bit on the initial load, so the transient effect is blunted.  I have two of them, so perhaps I can set them up (carefully) in parallel.  It's the AC that it takes me about 5 seconds to bring all the way up.  I'll have to work on that. I'm also trying not to make stupid mistakes like accidentally giving the 8842A a full 1000VAC (it is only rated for 700).  It didn't kill it, it just blinked at me--while reading  the voltage correctly-- until I realized what was going on.

I also tried a Fluke 27, a CAT III/1000V version.  It has an initial input resistance of ~5k so my DC didn't sag as much and I was able to start the AC higher and jump up in one step.  It only has mVAC, mVDC, Ohms, Continuity and Diode ranges and it withstood the full 1000VAC and 1000VDC on all of them. 

As for range switching, I think they do put some thought into that.  For example, the Auto Lo-Z function requires you to cross the OFF position to get in or out of it.  But things like hooking up to 600VAC, realizing you are in mV and just switching to VAC, that seems like a potentially destructive test to me.  Maybe you could do a combined lifecyle test with using your switch lifetime tester with the meter connected to 1000VAC! 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 03:48:22 pm
The concern would be engaging a low voltage clamp and opening the contact with a kV DC applied.  I don't see too many meters surviving that but I've never tried it. 

For AC, things could get interesting if you are suggesting that any frequency is open game.  We just need to stay below the printed voltage on the meter.   I cooked that UT61E+ doing just that and suspect that many of these cheap meters using only a PTC/s to limit the current would be damaged well below their claimed levels.    I'm not sure how that fits into your criteria of being robust. 

***
Consider the 121GW uses two PTCs in series for the low Z mode.   Where the UT61E, has a low voltage clamp which will shave off some insignificant amount, the 121GW is right across the inputs. 
***
Your Fluke 116 unlike my 115 (which has never been damaged and I still have) has a LowZ mode.  Maybe like the 121GW, it uses a couple of PTCs as well?  The plot thickens.   
***
As for range switching, I think they do put some thought into that.  For example, the Auto Lo-Z function requires you to cross the OFF position to get in or out of it.
That off position could be the end of the meter.  You had the meter in the lowZ, attached to a high current DC kV source, then turn it to the OFF position.  I doubt that will end well. 


A couple of demonstrations from John Ward's channel:

https://www.youtube.com/watch?v=mQpzwR7wLeo (https://www.youtube.com/watch?v=mQpzwR7wLeo)

https://www.youtube.com/watch?v=CUFVSc5ll4s (https://www.youtube.com/watch?v=CUFVSc5ll4s)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 01, 2021, 04:39:45 pm
The concern would be engaging a low voltage clamp and opening the contact with a kV DC applied.  I don't see too many meters surviving that but I've never tried it. 

I think the meter's main defense against that would be that the PTC quickly lowers the current to a level that a switch can maybe handle.  If you spin the dial with the power on, you may defeat that feature.  I suspect that even if the meter doesn't burn up on the spot, there would be cumulative damage.

Quote
For AC, thing could get interesting if you are suggesting that any frequency is open game.  We just need to stay below the printed voltage on the meter.   I cooked that UT61E+ doing just that and suspect that may of these cheap meters that only use a PTC to limit the current would be damaged well below their claimed level.    I'm not sure how that fits into your criteria.

I would say 1kHz and below is fair game, but unless the meter is specifically rated for more, I wouldn't expect them to really deal with HF AC.  My calibrator only goes to 1100VAC @ 1kHz (20 and 50kHz at lower voltages) so I also don't have the means to give them the jqs MeltCalTM treatment.  However, I think it would be reasonable for us to expect manufacturers to explicitly list these limitations in the specs.  Maybe if they were forced to think things all the way through and completely specify their products, they'd figure out why some manufacturers spend all that money on those expensive resistors.  I wonder how some of those meters would stand up to even something like 1kV@10kHz.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286971;image)

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1286977;image)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 04:57:38 pm
Your 116 specs the frequency to 50kHz.  Dave's 121GW, 1MHz.  Seems like the 121GW should handle 1MHz within the voltage limits.   Maybe...   Of course, I would think a meter with a spec'ed freq counter at 220MHz would be able to read 220MHz before the solder starts to reflow and the case melts.   

The concern would be engaging a low voltage clamp and opening the contact with a kV DC applied.  I don't see too many meters surviving that but I've never tried it. 
I think the meter's main defense against that would be that the PTC quickly lowers the current to a level that a switch can maybe handle.  If you spin the dial with the power on, you may defeat that feature.  I suspect that even if the meter doesn't burn up on the spot, there would be cumulative damage.

Maybe.  It would be easy to setup a simple test without a meter and just see if an arc could be drawn.    I would use a 1k resistor in series with the PTC, apply the 1kVDC across it, let the PTC heat up, then open the circuit.  It's nothing I have ever tried.     I'll make a clip of it. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 01, 2021, 05:37:35 pm
Your 116 specs the frequency to 50kHz.  Dave's 121GW, 1MHz.  Seems like the 121GW should handle 1MHz within the voltage limits.   Maybe...   

I don't see that in my manual and I know it won't measure HF AC--it works well to 2kHz and then starts to drop off.  The manual specifies accuracy only to 1kHz for TRMS. It lists the frequency counter function to 100kHz but doesn't specify a maximum input voltage as far as I can see, nor is there any explicit mention of maximum V-Hz, like there is with the F27.  Apparently mentioning V-Hz isn't in vogue any more, perhaps dV/dt is too complex of an issue...    Now as for giving the 121GW 6*108 V-Hz, I suspect that won't go well, but I wouldn't want to be around if you try it.  If you have a low-impedance 600VRMS 1 MHz source, that is.   :scared:

Quote
Of course, I would think a meter with a spec'ed freq counter at 220MHz would be able to read 220MHz before the solder starts to reflow and the case melts.

Silly you for believing anything printed on a UNI-T box..... :-DD   Did you ever figure out what the output voltage and power of that RF amp was? 
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 01, 2021, 05:50:22 pm
The 20J may be overkill but all you safety experts posting here already know where that number came from. 

Hmmm.  Is it because that is about the energy used in a defibrillator or because it matches up with the output of an electric fence charger (a powerful one)?  :-DD

Quote
You may not agree but hopefully you at least now have some understanding why I will continue to call my transients low energy.

Thanks for the detailed explanation.  Low is a relative term, of course, and relative to MOV ratings, IEC transients, etc, 20J is obviously much lower.  The comment I responded to was talking about damage to semiconductors, etc and there 20J  will pop the lid on quite a few devices.   I think the low energy events he was referring to are the sorts of noise, ESD or spikes that might get through normal filtering for reasons other than that they overwhelm the protection systems by simply exceeding their voltage or energy limitations.  Piezo igniters and 220MHz RF come to mind....


Also thanks for the explanation Joe, but I was also talking similar small energy surges, where basically only the fast rise time is what counts, and the only interesting parameter of the protection circuit is how fast they act, and what is the max voltage with the small energy spikes which will be let through.
The Up parameter is mostly the only thing specified at all, but that is at the max amp. rating so usualy no info about the reaction to the much weaker stuff.
Because even if a surge protector meets its Ka and thousend joule specs, there is no word about how it filters out the small surges which eventually leads to failures in electronics.
The surge protector manufacturer is not interested in building a circuit which clamps everything all the time, because than the MOVs etc eventually wear out, so I suppose most of the small spikes will hit the protection circuits of the electronics. But this is only a theory because not much testing going on on ACTUAL surge arrestors and input protection circuits on the net. But I understand if you are not interested in using the... Joe-gen for it.


And here is an important announcment for The Uni-t Ut60e Protection Circuit Variations Collector Society:
(short: TUUPCVCS)
There is a possibly really unique version aviable in Sweden, the Clas Ohlsson edition. Which is a kind of store chain. Being a swedish version I suppose maybe it comes with REAL fuses from the Nobel factories.
(Note for the Fluke test guys: Reinforce the blast shield if testing those!)
Being a rarity and a collectors item soon, I consider sending it to anyone for a symbolic 2000 Euro price. (Shipping included) It would be a solid investmen in these hectic days! (No I don't have it yet, so can't post pictures.)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 06:19:50 pm
Silly you for believing anything printed on a UNI-T box..... :-DD   Did you ever figure out what the output voltage and power of that RF amp was? 

The amplifier's output voltage will be load dependent.  Part 2 shows how the PTCs behave at higher frequencies and how there was nothing else to limit the current.  It also shows how the Brymen BM78x would easily handle this because Brymen engineers were smart enough to use a device that was more stable (a resistor).     

To melt the solder what, 20W - 40W?  A bit of damage to the PCB, 80W?   Say the meter presents 5 ohms @ 120MHz,  20V would get you 80W.   Just a ballparkish guess.  Let's say double that.   Does 40V seem like a lot to you?  I mean, I thought you were all about kVs?!   :-DD   

***
Looks like I was able to load it to about 70W in that range.   Highest seems around 100V with a 50ohm load at 100MHz.  It makes a decent lab amplifier.   

https://www.eevblog.com/forum/projects/home-made-pa-and-load/msg635912/#msg635912 (https://www.eevblog.com/forum/projects/home-made-pa-and-load/msg635912/#msg635912)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 01, 2021, 06:55:13 pm
To melt the solder what, 20W - 40W?  A bit of damage to the PCB, 80W?   Say the meter presents 5 ohms @ 120MHz,  20V would get you 80W.   Just a ballparkish guess.  Let's say double that.   Does 40V seem like a lot to you?  I mean, I thought you were all about kVs?!   :-DD

4.8*109 V-Hz seems a bit much for direct connection to almost any test instrument, let alone a DMM.  Even my 8505A would like to stay below 2*107.  And your 8506A, despite being a specialized HF AC instrument, is only good for half that.  Having a wirewound resistor or a common-mode toroid right at the front end might help in these extreme cases, but I suspect that level of RF will burn up lots of things.  If you're doing it some more, I'll watch from here.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1287016;image)
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 01, 2021, 08:09:49 pm
There must separate path injecting current into DUT for resistance and capacitance, and this composite 1 MOhm resistor is measurement path for these ranges. There will be transistor clamp after it somewhere before going into DMM chip. ...

I would have said the complete opposite: The "voltage path: is 10MOhms impedance so even a 10,000 volt input is only going to pass 1mA - very easy to clamp and not going to hurt much. It wasn't complete;y crazy to think that chain of resistors was the voltage input, and indeed it is the voltage range protection on my "cheap meter" and many others.

The Ohms/Diode/Capacitance range requires the meter to apply a current to the DUT so it's much lower low impedance. It makes sense to have all the PTCs and MOVs and stuff on those ranges, and some meters appear to do it that way..

My LIDL meter is interesting because it mixes both, it has a 10MOhm chain for the voltage input and a 1MOhm chain for whatever the slightly lower chain turns out to be.

Nice job sir.   Do you have the tools/skills needed to remove one of the resistors that make up the chain R8-R2?

I actually bought a cheapo hot air gun a couple of weeks ago. Maybe this is the opportunity to take it out of the box.  :)

Title: Re: Handheld meter robustness testing
Post by: floobydust on October 01, 2021, 08:53:59 pm
Consider the newer small Fluke multimeter input protection circuit, instead of desoldering things.
You can see the three main channels, the 1MEG, 10MEG and how they are used.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 01, 2021, 09:12:43 pm
...
And your 8506A, despite being a specialized HF AC instrument, is only good for half that.  Having a wirewound resistor or a common-mode toroid right at the front end might help in these extreme cases, but I suspect that level of RF will burn up lots of things.  If you're doing it some more, I'll watch from here.
...
I have no plans to do much testing with that old Fluke after saving it from scrap.  It's only job is to hang out next to my 8000A and act as a reminder of days of old.  :-DD
 
When I showed Part 2, I talked about the resistor becoming more inductive while the PTC became more capacitive.  No doubt that added resistor is what saves it.   

It seems like you are backing down about surviving the max marked voltage on the face of the meter.   Rather we need to actually read the manual and understand the specs to save the meter.   I guess that is true for the ESD and other faults as well.   After all, who in their right mind is going to try and measure the output of their amplifier directly with a meter ....  oh wait... there was that radio hobbyist who connected their low cost VNA directly to their radio to advance the art.    :-DD   They were special.

I agree that working with RF is a bit out there and I would also say even a kVDC with 100s of mA wouldn't be common but I don't test these.   I've seen people post about damaging them with a MOT and their lawn mower mags but I won't go there.   I was really more interest in how they held up with low energy short transients as it seems that has been how I have damaged them in the past.  ESD is a problem where I live but again, I wasn't expecting to see any meters be effected by it.   

As you can see, testing robustness isn't so cut and dry.   I still find it an interesting topic. 

I actually bought a cheapo hot air gun a couple of weeks ago. Maybe this is the opportunity to take it out of the box.  :)
I've soldered with a heat gun for many years.  Your boards may be lead free and require more heat than you can get out of your gun.  I would practice with the cheap meter first.  Maybe blend in some tin lead on the Fluke to help pull them until you get an idea how to use the new gun.  Always new things to learn. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 01, 2021, 09:13:15 pm
Consider the newer small Fluke multimeter input protection circuit, instead of desoldering things.
You can see the three main channels, the 1MEG, 10MEG and how they are used.

Series PTCs and a trimpot?  What model(s)?
Title: Re: Handheld meter robustness testing
Post by: floobydust on October 01, 2021, 10:53:06 pm
That's the Fluke 15, 17 family. The 101, 107 only uses two MOV's. Point is it's been optimized beyond the classic 87 input protection, and for cost as well.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 02, 2021, 12:47:25 am
It seems like you are backing down about surviving the max marked voltage on the face of the meter.   Rather we need to actually read the manual and understand the specs to save the meter. 

Not 'backing down'.  Clarifying!  :)

Yes, as I was going on and on about V-Hz, I would reasonably expect the CAT rating on the face to apply to DC and mains, so say at least up to 400Hz?  Unless there is a type-N connector on the front.  The problem with V-Hz limitations is that it can't be easily condensed into something that you can print on the front of the meter.  Even just a V-Hz number, as if the average user can do math in their head, won't help.  I'm pretty sure that almost any meter can take 10mV @ 1GHz, but not many will do well at 1GV @ 10mHz!  So yes, that is always going to be an RTFM specification, its just a shame that most manuals omit this entirely, even when the meter has specifications that might invite disaster.

A while back I was looking at some HVDC power supplies used for plasma deposition systems.  I ended up not working on them at all because they don't have much market value, but I did wonder how I was going to safely measure even the primary side.  These are 480V 3PH input SMPS using big IGBT modules, the supplies are the size that you can carry them in a pickup truck but you would use a forklift to put them in.  So you have a 600-700VDC bus and a SMPS probably operating in the tens of kHz.  If you carefully RTFM for a Fluke 289, you would see that over 50VAC and 10kHz, accuracy is 'not specified', but the 2*107 V-Hz limitation is hidden away elsewhere and not easy to find.  Most other meters do not have specifications either on the front or in the manual that would tell you not to use them for this application. 

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 02, 2021, 12:48:03 am
Your 116 specs the frequency to 50kHz.  Dave's 121GW, 1MHz.  Seems like the 121GW should handle 1MHz within the voltage limits.   Maybe...   Of course, I would think a meter with a spec'ed freq counter at 220MHz would be able to read 220MHz before the solder starts to reflow and the case melts.   

The concern would be engaging a low voltage clamp and opening the contact with a kV DC applied.  I don't see too many meters surviving that but I've never tried it. 
I think the meter's main defense against that would be that the PTC quickly lowers the current to a level that a switch can maybe handle.  If you spin the dial with the power on, you may defeat that feature.  I suspect that even if the meter doesn't burn up on the spot, there would be cumulative damage.

Maybe.  It would be easy to setup a simple test without a meter and just see if an arc could be drawn.    I would use a 1k resistor in series with the PTC, apply the 1kVDC across it, let the PTC heat up, then open the circuit.  It's nothing I have ever tried.     I'll make a clip of it.

https://www.youtube.com/watch?v=gKK7Dl-fnjk (https://www.youtube.com/watch?v=gKK7Dl-fnjk)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 02, 2021, 01:02:47 am
That's the Fluke 15, 17 family. The 101, 107 only uses two MOV's. Point is it's been optimized beyond the classic 87 input protection, and for cost as well.

That's market segmentation for you!  Still, depending on what the actual components are, it looks passable, especially if they're certified in China.   :-DD 

I'd prefer the resistor to the PTC, it almost seems bizarre specifying either or.  I'd guess you can get by with 2 MOVs, a PTC and a resistor as long as you have a simple meter (no Lo-Z) and use good parts.
Title: Re: Handheld meter robustness testing
Post by: Per Hansson on October 02, 2021, 09:23:59 am
And here is an important announcment for The Uni-t Ut60e Protection Circuit Variations Collector Society:
(short: TUUPCVCS)
There is a possibly really unique version aviable in Sweden, the Clas Ohlsson edition. Which is a kind of store chain. Being a swedish version I suppose maybe it comes with REAL fuses from the Nobel factories.
(Note for the Fluke test guys: Reinforce the blast shield if testing those!)
Being a rarity and a collectors item soon, I consider sending it to anyone for a symbolic 2000 Euro price. (Shipping included) It would be a solid investmen in these hectic days! (No I don't have it yet, so can't post pictures.)
I only found a UT61D, not UT61E: https://www.clasohlson.com/se/Multimeter-med-USB-UNI-T-UT61D/p/36-4717 (https://www.clasohlson.com/se/Multimeter-med-USB-UNI-T-UT61D/p/36-4717)
That said your post is funny.
However it seems to be the bog standard "Chinese" version and not the "GS" branded version because the listed spare fuses for it are 1A 240V for the mA range.
But they are 0.5A 600v in the "GS" version.
And the linked manual on their page also claims the instrument is CAT-IV rated at 600v and CAT-III at 1000v which we all know is blatantly false.
(The GS rated meter is CAT-III 300v and CAT-II 600v but even that is a stretch if you follow the link in my quote below from Joe).
Title: Re: Handheld meter robustness testing
Post by: Per Hansson on October 02, 2021, 09:29:34 am
Left on for 10 seconds, survives just fine at the nominal 245V here. Readings a smidge low as the PTC recovers.

So I'm curious about why these tests would be conducted at those levels on meters with a CAT-anything label at.  Should the meter not withstand, without damage, the application of full rated voltage (1000V in this case) to any input on any setting?  AFAIK, even supposedly fragile CAT I bench meters will pass that test.  Some older pre-CAT bench meters have separate, lower specifications for voltage protection on ohms and such, but even the old Fluke 8842A will pass that test.

Link to the persons posts who had asked about this may be found here:
https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/ (https://www.eevblog.com/forum/repair/uni-t-ut61e-diode-mode-repair/)

Some of the smaller PTCs are only rated for 500V.  Some meters have only a single PTC which if the low voltage clamp is active, will have well over 900V across them....  Maybe....  Turn the dial, I suspect you will get a light show. 

***
Quote
I'm referring to meters that some claim to be properly rated, not ones where there isn't any dispute that the CAT info printed on them is a bad joke.

Sorry, I missed that part.   If a KVDC were applied with unlimited current and the function switch were rotated, I suspect you would burn the contacts on most meters.  I wouldn't recommend anyone attempt it.
It was me who requested the test :)
Thanks to both Joe and Dave for performing them!
It is nice to see this model survives at least, as can be seen in the link from Joe's quote above the old "GS" model did not fare so well, at least the revision I have!
Title: Re: Handheld meter robustness testing
Post by: floobydust on October 02, 2021, 10:08:11 am
I'm not sure what loophole is being exploited.
UT61A,B,C,D,E 61010 certificate report #17014567 003 by TÜV Rheinland (China) Ltd. in Beijing is for the "GS-Mark" to Cat. II 600V, Cat. III 300V with 600V fuses, three MOV's.
Many Uni-T tests are TÜV Rheinland (Shenzhen Office) results then carried over to TÜV Rheinland Nurenburg.

Yet the products are in the Intertek database as well. I think you can carry over certificates between agencies for further laundering of details.
It might be a case of the Golden Sample to TÜV, with smoke and mirrors about the National Differences product builds.
So the fact the GS special is a different build for i.e. North America gets lost.


On another note
From another TÜV 61010 test report, they added tests:
16.2DV.1
"Multifunction meters and similar equipment shall be tested by changing the function /range selector to all possible settings while connected to the maximum rated source."
16.2DV.2
"Compliance is checked by testing to verify no HAZARD occurs when switching selector settings."
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 02, 2021, 10:10:38 am
And here is an important announcment for The Uni-t Ut60e Protection Circuit Variations Collector Society:
(short: TUUPCVCS)
There is a possibly really unique version aviable in Sweden, the Clas Ohlsson edition. Which is a kind of store chain. Being a swedish version I suppose maybe it comes with REAL fuses from the Nobel factories.
(Note for the Fluke test guys: Reinforce the blast shield if testing those!)
Being a rarity and a collectors item soon, I consider sending it to anyone for a symbolic 2000 Euro price. (Shipping included) It would be a solid investmen in these hectic days! (No I don't have it yet, so can't post pictures.)
I only found a UT61D, not UT61E: https://www.clasohlson.com/se/Multimeter-med-USB-UNI-T-UT61D/p/36-4717 (https://www.clasohlson.com/se/Multimeter-med-USB-UNI-T-UT61D/p/36-4717)
That said your post is funny.
However it seems to be the bog standard "Chinese" version and not the "GS" branded version because the listed spare fuses for it are 1A 240V for the mA range.
But they are 0.5A 600v in the "GS" version.
And the linked manual on their page also claims the instrument is CAT-IV rated at 600v and CAT-III at 1000v which we all know is blatantly false.
(The GS rated meter is CAT-III 300v and CAT-II 600v but even that is a stretch if you follow the link in my quote below from Joe).

True, its the D, I just saw it in the shop remembering it was the E. Was even thinkering buying one, because the special edition could be someting nice.
But see, you are also not perfectly accurate in this case, as when you open the first user manual, Ver. 20140523 than you get the 240V fuses listed. BUT!
If you open all the other manual versions, than you get 1000V fuses listed. 
Now I have to raise the price to 5000Euro, because I either brake into the shop during the night, or without being noticed have to brake all the plastic boxes during the day, tear down the meters, and check what's inside. And possibly do that in different shops in the country.
Which meter has which protection within the Clas Ohlsson Edition? :) (of the D version...)
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on October 02, 2021, 01:30:19 pm
https://www.youtube.com/watch?v=gKK7Dl-fnjk (https://www.youtube.com/watch?v=gKK7Dl-fnjk)
From the video: "... I think it would do the meter in." Proceeds to film in slow motion plasma with a 5mm arc from 1000V DC power supply.  :popcorn:

I am no expert but I too think "it would do the meter in".

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 02, 2021, 02:12:29 pm
From another TÜV 61010 test report, they added tests:
16.2DV.1
"Multifunction meters and similar equipment shall be tested by changing the function /range selector to all possible settings while connected to the maximum rated source."
16.2DV.2
"Compliance is checked by testing to verify no HAZARD occurs when switching selector settings."

I don't see any reference to AC or DC.  I wonder if there might be a presumption that CAT voltages only refer to AC at mains frequencies.  Either might damage a meter in this case, but AC would surely be less likely to pose a hazard.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 02, 2021, 02:18:16 pm
So I was contemplating testing my Fluke 289 (CAT III/1000V CAT IV/600V) with 1000V on all ranges and I decided to RTFM first.  The F289 is a very nice instrument and I don't mind the menus, but the manual and specifications are complex and not straightforward or intuitive--the type of thing you need to have on the bench to refer to, not the type you can read once and remember it.   I found this gem:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1287619;image)
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 02, 2021, 04:19:34 pm
Consider the newer small Fluke multimeter input protection circuit, instead of desoldering things.

I was thinking I could maybe take the spring contact out of the range selector - it breaks the circuit, it's much easier!

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 02, 2021, 04:28:57 pm
...
Even just a V-Hz number, as if the average user can do math in their head, won't help.  I'm pretty sure that almost any meter can take 10mV @ 1GHz, but not many will do well at 1GV @ 10mHz!  So yes, that is always going to be an RTFM specification, its just a shame that most manuals omit this entirely, even when the meter has specifications that might invite disaster.
...

...
Even my 8505A would like to stay below 2*107.  And your 8506A, despite being a specialized HF AC instrument, is only good for half that.  Having a wirewound resistor or a common-mode toroid right at the front end might help in these extreme cases, but I suspect that level of RF will burn up lots of things.  If you're doing it some more, I'll watch from here.
...

I would expect that my first Fluke DMM was highly susceptible to being damaged by RF (or looking at it sideways).   I suspect as the front ends of these handhelds evolved, the need to derate them was less important.  Of course, you still end up with meters like the UNI-T UT61E+ having some sort of frequency counter speced at 220MHz with a couple of PTCs in series, but I suspect most modern robust meters would not have a problem.   Like I had shown with the BM78x, with the same setup that damaged the UT61e+, the PTCs had very little heat.   As I demonstrated, that resistor was fairly stable to 50MHz and a 1kohm just doesn't present much of a load to the small amplifier. 

I don't mind running other tests if you had something in mind.  I could take that same resistor/PTC we just used and run them any way you like.  The same with that Brymen BM78x prototype.   Let me know.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 02, 2021, 04:31:13 pm
Consider the newer small Fluke multimeter input protection circuit, instead of desoldering things.

I was thinking I could maybe take the spring contact out of the range selector - it breaks the circuit, it's much easier!
You're firing on all eight cylinders today I see.   Still, it was a good opportunity to try out that heat gun. 
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on October 02, 2021, 05:38:10 pm
Consider the newer small Fluke multimeter input protection circuit, instead of desoldering things.

I was thinking I could maybe take the spring contact out of the range selector - it breaks the circuit, it's much easier!

Just don't lose the bugger!
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 02, 2021, 05:56:46 pm
I would expect that my first Fluke DMM was highly susceptible to being damaged by RF (or looking at it sideways).   I suspect as the front ends of these handhelds evolved, the need to derate them was less important.  Of course, you still end up with meters like the UNI-T UT61E+ having some sort of frequency counter speced at 220MHz with a couple of PTCs in series, but I suspect most modern robust meters would not have a problem.   Like I had shown with the BM78x, with the same setup that damaged the UT61e+, the PTCs had very little heat.   As I demonstrated, that resistor was fairly stable to 50MHz and a 1kohm just doesn't present much of a load to the small amplifier. 

I don't mind running other tests if you had something in mind.  I could take that same resistor/PTC we just used and run them any way you like.  The same with that Brymen BM78x prototype.   Let me know.

I have 3 of the 8000A models in my junkpile, they're all toasted and they all have evidence that they've been soldered on during their lifetimes.  But those were early days in the whole field, not just for Fluke.  Meters may be more durable nowadays, but they still have limits and I, for one, would like to see those limits specified in detail--but they usually aren't. 

I haven't see the video of you giving any other meters the jqs MeltCalTM treatment, I'll have to go look.  I think it might be interesting to try to determine what parts are used in the meters and then characterize and test those--and look at datasheets if possible--to see who is using what and how the expected component performance matches up with the claimed performance of the meter.

To start, for Fluke I'm fairly sure those big PTCs in the larger CAT III/1000V meters are something like this:

https://www.mouser.com/datasheet/2/18/amphenoladvancedsensors_YS4020-1157120.pdf (https://www.mouser.com/datasheet/2/18/amphenoladvancedsensors_YS4020-1157120.pdf)

and the green input resistors are Bourns WS5M:

https://www.mouser.com/datasheet/2/54/ws-778275.pdf (https://www.mouser.com/datasheet/2/54/ws-778275.pdf)

Those Bourns resistors have a nice surge rating chart:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1287838;image)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 02, 2021, 06:42:12 pm
I have 3 of the 8000A models in my junkpile, they're all toasted and they all have evidence that they've been soldered on during their lifetimes.  But those were early days in the whole field, not just for Fluke.  Meters may be more durable nowadays, but they still have limits and I, for one, would like to see those limits specified in detail--but they usually aren't. 

I haven't see the video of you giving any other meters the jqs MeltCalTM treatment, I'll have to go look.  I think it might be interesting to try to determine what parts are used in the meters and then characterize and test those--and look at datasheets if possible--to see who is using what and how the expected component performance matches up with the claimed performance of the meter.
...
I wouldn't have spent any time rebuilding my 8000A had it not been my first DMM.  Beyond it's sentimental value and being the catalyst for running these tests,  it has no other redeeming qualities.   

After the attached comment,  I demonstrated the BM78x at over 100MHz during Part 2 of the UT61E+ review.  At these higher frequencies, the majority of the voltage drop will be across the resistors, not the PTCs.   I'm guessing this would have been obvious to all the radio hobbyist.   
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 02, 2021, 09:18:58 pm
After the attached comment,  I demonstrated the BM78x at over 100MHz during Part 2 of the UT61E+ review.  At these higher frequencies, the majority of the voltage drop will be across the resistors, not the PTCs.   I'm guessing this would have been obvious to all the radio hobbyist.   

OK, so I see you actually did some characterization of components.  I'm not a radio hobbyist per se, but this would not have been so obvious to me because I wouldn't have known what the parasitic capacitance of the PTCs was.  MOVs I know about, PTCs I never thought about.  Of course it makes sense in hindsight.

Is that resistor a Bourns WS5M or similar?  I wonder what its reactance to your piezo igniter would be.  Perhaps we need a MacroVNA, with a 1kW output.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 02, 2021, 10:09:38 pm
I suspect the OP was not thinking about the AC characteristics which is a bit odd as we were working with AC.   :-DD  Then again, if you never work with AC, you may think of a resistor as a resistor, not a complex device with RLC components to it.  You may also think of a wire as a short.   When I was playing with that fastest breadboard oscillator contest, basically I made the whole circuit from wire + transistor.

We have some idea on the current waveshape of the grill starter.  The little pocket VNA will work to about 300MHz.  The other low cost one, a bit over 4GHz.  It would not be a problem to look at it at higher frequencies but I would ditch the breadboard.   :-DD

I've looked at a few different brands/types of resistors.  That particular one was made by Ohmite.  Have a look at the OX/OY series.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 03, 2021, 08:24:27 am
You're firing on all eight cylinders today I see.   Still, it was a good opportunity to try out that heat gun.

I'll try it on one of the "cheap" ones first.  :)

Just don't lose the bugger!

OK, I took out the spring from the selector switch.

Results:
a) VDC/VAC ranges work just fine.
b) mV AC range doesn't work. Shows a small reading which changes if I wave the leads around. Doesn't go to zero when I short the probes.
c) All the other ranges show 0.00 on screen.
d) Continuity range beeps continuously if I select it.
e) Diode range still lights up LEDs, resistance range still outputs a test voltage.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 03, 2021, 02:46:20 pm
OK, I took out the spring from the selector switch.

Now that you know that the PTC side can be used for an output as well as an input, and you know the other leg is an input only.  How do they clamp  both legs when the resistance function is selected?     Are you going to trace it out and provide us some drawings?

Yesterday my entire day consisted of making a few minute video.   Today should be a bit more exciting.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 04, 2021, 03:41:52 am
Perhaps we need a MacroVNA, with a 1kW output.

The 1kW VNA might not be so funny.  I got the calibrator (the actual project I'm working on here) working for the moment and I tried testing meters again.  In troubleshooting the calibrator I had set up one DMM, the trusty F27, to monitor the output current, so I left it in place. 

The F116 in AutoV/Lo-Z mode (or probably any of the PTC-protected modes) would draw about 1.8mA @ 600VDC or 600VAC/60Hz.  At 600VAC/400Hz, this climbed to about 3mA, and at 1kHz, 5mA.  I tried the same thing with the F27, but it had much higher currents--20mA +-- and at its 1000V level, the calibrator simply could not supply enough current without tripping off.  I did observe the same thing--current climbing with frequency. 

I have no idea how much power is being dissipated and how much is imaginary, but I suppose another experiment is in order.  I'll have to set up some resistors and a scope to see what the angle is between current and voltage at 50-1000Hz--so not a 1kW VNA, but at least a 1kV version!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 04, 2021, 01:34:18 pm
I assume these are all after the PTCs have switched.   Otherwise for LowZ, I would expect the current to be much higher.   At a kHz, I doubt you will see much change.   

For the F27, you could for example, try using the AC line to get the PTCs to switch, then quickly attach it to the calibrator.  Maybe just a DPDT switch to prevent it from cooling.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 05, 2021, 01:49:08 pm
In part 4, the UT61E+ is temperature cycled, dropped and transient tested.   I also use the NanoVNA to compare the 61E+'s input impedance with a few other meters. 

https://www.youtube.com/watch?v=HsEAtIfPRzA (https://www.youtube.com/watch?v=HsEAtIfPRzA)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 05, 2021, 04:31:07 pm
For the F27, you could for example, try using the AC line to get the PTCs to switch, then quickly attach it to the calibrator.  Maybe just a DPDT switch to prevent it from cooling.

The calibrator is now up to snuff.  It will put out more current at lower voltages, up to about 250 volts, above that it is limited to 8-10mA continuous.  For the F27, when I monitor current, I can see that the PTCs do take some time to heat up, they don't 'switch' quickly at all.  At 250V it is 'over the hump' so to speak, but the huge PTC in the F27 is still beyond what the calibrator can handle in one go.  If I give it a 1000VAC jolt cold, the current goes to a bit over 20mA, as would be expected given it's ~4.6K cold combination of the 3.5K resistor and PTC--but this is too much current and the calibrator trips off.  The two series PTCs of the F116 are a bit easier for it, but even at 600V the current takes some time to settle.  Anyway, I can now energize both meters at their rated voltage, although the F27 has to be brought up in stages.

Quote
I assume these are all after the PTCs have switched.   Otherwise for LowZ, I would expect the current to be much higher.   At a kHz, I doubt you will see much change. 

Well, there's the problem--it does change, and a lot.  I tested them at low and high voltages with different frequencies.  I used 6V and 600V for the F116, then 15V and 1000V for the F27.  I needed to use the higher voltage on the low end for the F27 because it doesn't have a Lo-Z mode, so I have to overwhelm the low voltage clamps in whatever circuit I'm using (OHMS in this case) so that I see mostly the PTC/resistor characteristics.

At 6VAC in 'AUTO V/Lo-Z',  the F116 had a current of about 2.0mA @ 50Hz, and that didn't change much at 1kHz or even 10kHz.  However, at 600VAC, it had about 1.9mA at 50Hz, but that rose to 5.1mA @ 1kHz. 

The F27 at 15VAC stayed in the 2.1-2.3 range, not totally steady because the OHMs circuit was reacting a bit.  At 1000VAC, it showed about 2.0mA @ 50Hz, but raising the frequency to 1kHz caused a surge to about 7mA and then it settled back down to 5.4mA.

Those are huge differences from 50Hz to 1kHz, but only at higher voltages.  I have to wonder if the trend would continue if you kept going--the calibrator is maxed out.  I'm only at 106 V-Hz but some of these meters are supposedly good for 10X or 20X more.  The next time I place an order maybe I'll get a few of those big dark grey monster PTCs that you find in the larger CAT III/1000 Flukes and try to characterize them.  It looks like they pick up 500-1000pF when they warm up. Maybe they should be called thermisto-varactors. 


Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 05, 2021, 05:40:34 pm
Quote
I assume these are all after the PTCs have switched.   Otherwise for LowZ, I would expect the current to be much higher.   At a kHz, I doubt you will see much change. 

Well, there's the problem--it does change, and a lot.  I tested them at low and high voltages with different frequencies.  I used 6V and 600V for the F116, then 15V and 1000V for the F27.  I needed to use the higher voltage on the low end for the F27 because it doesn't have a Lo-Z mode, so I have to overwhelm the low voltage clamps in whatever circuit I'm using (OHMS in this case) so that I see mostly the PTC/resistor characteristics.

At 6VAC in 'AUTO V/Lo-Z',  the F116 had a current of about 2.0mA @ 50Hz, and that didn't change much at 1kHz or even 10kHz.  However, at 600VAC, it had about 1.9mA at 50Hz, but that rose to 5.1mA @ 1kHz. 

The F27 at 15VAC stayed in the 2.1-2.3 range, not totally steady because the OHMs circuit was reacting a bit.  At 1000VAC, it showed about 2.0mA @ 50Hz, but raising the frequency to 1kHz caused a surge to about 7mA and then it settled back down to 5.4mA.

Those are huge differences from 50Hz to 1kHz, but only at higher voltages.  I have to wonder if the trend would continue if you kept going--the calibrator is maxed out.

"Not much change" meaning Amps vs mA.  At these low frequencies, Xc is not going to be a problem.   As you move up in frequency, Xc will dominate and we can damage the parts with a very low voltage, unless there is something else to limit the current.   Perhaps a resistor...

Quote
I'm only at 106 V-Hz but some of these meters are supposedly good for 10X or 20X more.  The next time I place an order maybe I'll get a few of those big dark grey monster PTCs that you find in the larger CAT III/1000 Flukes and try to characterize them.  It looks like they pick up 500-1000pF when they warm up. Maybe they should be called thermisto-varactors.

 :-DD 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 05, 2021, 05:59:11 pm
"Not much change" meaning Amps vs mA.  At these low frequencies, Xc is not going to be a problem.   As you move up in frequency, Xc will dominate and we can damage the parts with a very low voltage, unless there is something else to limit the current.   Perhaps a resistor...

Yes, the resistor is key at low voltage and much higher frequencies.  But take the case of the F116 running at 600V and continuing to ramp up the frequencies.  If you just assume that the PTC goes to a state of very high resistance but a capacitance of 0.5nF, the current will go high enough (~70mA) to exceed the rated power of the resistor (which I'm presuming is 5W for now) at around 40kHz.  So unless there is some other change, by 100kHz it has likely unsoldered itself if the PTC hasn't come undone first.  This is probably a bit of a far-fetched example, but perhaps not when it comes to VFD drives and such.  In any case, what caught my eye was the reactance change at higher voltages that wasn't there at lower ones.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 05, 2021, 06:53:23 pm
"Not much change" meaning Amps vs mA.  At these low frequencies, Xc is not going to be a problem.   As you move up in frequency, Xc will dominate and we can damage the parts with a very low voltage, unless there is something else to limit the current.   Perhaps a resistor...

Yes, the resistor is key at low voltage and much higher frequencies.  But take the case of the F116 running at 600V and continuing to ramp up the frequencies.  If you just assume that the PTC goes to a state of very high resistance but a capacitance of 0.5nF, the current will go high enough (~70mA) to exceed the rated power of the resistor (which I'm presuming is 5W for now) at around 40kHz.  So unless there is some other change, by 100kHz it has likely unsoldered itself if the PTC hasn't come undone first.  This is probably a bit of a far-fetched example, but perhaps not when it comes to VFD drives and such.  In any case, what caught my eye was the reactance change at higher voltages that wasn't there at lower ones.

0.5nF would give us 7957.75k at 40kHz.  In series with a 1k, 8957.75k.   With 600Vrms, (assuming the low voltage clamp is active an has no loss) the current would be 66.98mA.  The power dissipated by the resistor would be 4.49 Watts.    Changing to 100kHz would cause the resistor to dissipate 20.57 Watts. 

So, I think your math is correct.  Now the question is the capacitance at these higher frequencies once the part has switched.   Where is the 500pF coming from?  If it were 50pF we would be talking under half a Watt.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 05, 2021, 07:09:19 pm
Section 6.2 Figure 7 provides some insight.

Quote
So use of the PTC thermistor in the AF and RF ranges is not possible, meaning that applications are restricted to DC and line frequency operation.

https://www.tdk-electronics.tdk.com/download/408374/d78540dfe0589d2bd90cabef477c90b9/pdf-general-technical-information.pdf (https://www.tdk-electronics.tdk.com/download/408374/d78540dfe0589d2bd90cabef477c90b9/pdf-general-technical-information.pdf)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 05, 2021, 08:01:47 pm
Section 6.2 Figure 7 provides some insight.

https://www.tdk-electronics.tdk.com/download/408374/d78540dfe0589d2bd90cabef477c90b9/pdf-general-technical-information.pdf (https://www.tdk-electronics.tdk.com/download/408374/d78540dfe0589d2bd90cabef477c90b9/pdf-general-technical-information.pdf)

Excellent find!  That explains what I'm seeing.  And 6.1 refers to the hot PTC having a high voltage coefficient as well, which just makes things even more complicated.

Quote
Where is the 500pF coming from?

My off-the-cuff guesstimate of what (in capacitive reactance terms) would account for the extra 3mA of current going from 50Hz to 1kHz.  If/when I get some samples, I'll try to determine the relationships between voltage, current, frequency and phase.  Now it's back to my bulk tantalum capacitor replacement project....
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 05, 2021, 08:19:57 pm
Keep in mind, using your 500nF, 40kHz, 1k resistor that the power dissipation for the PTC is 36 Watts. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on October 05, 2021, 08:26:33 pm
Keep in mind, using your 500nF, 40kHz, 1k resistor that the power dissipation for the PTC is 36 Watts.

Well, they did unsolder themselves in your case!  But we don't know the power dissipation because we don't know what the phase angle between I and V across the PTC is.  The resistor can't escape the heat so easily. This is one of the things I'd like to test on part samples, rather than cooking a nice meter.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 06, 2021, 01:27:11 am
Now these are some classic comments!   There's just so many good points but that last sentence of Capture5 is priceless.   I never knew I was a 121GW fanboy!   :-DD :-DD :-DD   

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 06, 2021, 02:10:01 am
The viewer's have spoken. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 06, 2021, 04:03:43 am
In part 4, the UT61E+ is temperature cycled, dropped and transient tested.   I also use the NanoVNA to compare the 61E+'s input impedance with a few other meters. 

it survived the low voltage zapper?

You know what that means, joe? You're going to have to buy another UT61E+ so you can repeat the tests on an "unmodified" one.  :-DD
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 06, 2021, 10:58:39 am
Now these are some classic comments!   There's just so many good points but that last sentence of Capture5 is priceless.   I never knew I was a 121GW fanboy!   :-DD :-DD :-DD
Man, those are precious! He clearly did not watch the video.

It is very easy to throw as many digits as possible on a screen if you don't care about accuracy - also, if you rely on a multimeter to have a reliable capacitance, inductor or transistor test, you are doing it wrong.

Also... parts operating from 0~50C?!? Perhaps in Shenzhen's specials.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 06, 2021, 12:34:56 pm
In part 4, the UT61E+ is temperature cycled, dropped and transient tested.   I also use the NanoVNA to compare the 61E+'s input impedance with a few other meters. 

it survived the low voltage zapper?

You know what that means, joe? You're going to have to buy another UT61E+ so you can repeat the tests on an "unmodified" one.  :-DD

Videos up.   

We will see how it holds up to cycling the switch.  That has been a weak point for the UNI-T meters I have seen getting a little use.  I looked at the free HF meter and those cheap ANENGs.  Surely it will hold up better than them and the detent spring won't crack like the Keysight meter.  My expectations are low for the UT61E+.     
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 06, 2021, 12:48:55 pm
...
Also... parts operating from 0~50C?!? Perhaps in Shenzhen's specials.
That was the first comment I saw from them.  Painfully lost.  I was going to provide them a few links but after reading the second post, knew they are already an expert and would never read them. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 06, 2021, 03:56:49 pm
Keep in mind, using your 500nF, 40kHz, 1k resistor that the power dissipation for the PTC is 36 Watts.

Well, they did unsolder themselves in your case!  But we don't know the power dissipation because we don't know what the phase angle between I and V across the PTC is.  The resistor can't escape the heat so easily. This is one of the things I'd like to test on part samples, rather than cooking a nice meter.

Yes, the resistor is key at low voltage and much higher frequencies. 

I agree that the resistor is key.   Using your 0.5nF, but 2 PTCs in series, and 1MHz @ 25Vrms.    I get  Xc = 318 ohms and a current of 39.3mA.  Each PTC would dissipate 490mW.   Not much.   

At 120MHz @ 25Vrms, where I damaged the meter, Xc = 2.65 ohms.   Current is now 4.7A and the power of each PTC is 59Watts.   

Staying with the 120MHz @ 25Vrms, but swapping one PTC for a 1k resistor.   The current drops to 25mA.   The resistor dissipates 622mW and the PTC 1.65mW.   

While I have a few RF amplifiers as well as some low frequency ones, I don't have anything that will create 600Vrms at 10s-100s of kHz.   Your idea of using a VFD drive seems like it may be the solution if you can find one that would run up that high. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 06, 2021, 11:20:22 pm
She has a whole 200 cycles on her.  50,000 cycles  from off to NCV back to off as one full cycle.  None of that half cycle rubbish.  No cleaning the switch every few cycles.  No sticky notes, but instead an actual meter to read the contact resistance.   Listen to her click! 

https://www.youtube.com/watch?v=qeG395kJ4fY (https://www.youtube.com/watch?v=qeG395kJ4fY)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 08, 2021, 02:38:15 am
What a difference a day makes.   It has a long way to go...

https://www.youtube.com/watch?v=DYdw72vF9es (https://www.youtube.com/watch?v=DYdw72vF9es)
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 08, 2021, 06:07:37 am
Sounding like a Keysight.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 08, 2021, 12:39:08 pm
Sounding like a Keysight.
But we were told by the one reviewer, they put 10s of thousands of cycles on the same Keysight meter every year.   Their rebuttal video on the Keysight where they couldn't even bother to show the video detent spring was the last time I watched any of their content.    Looks like they reviewed this meter as well.  Based on the Keysight, I bet the UNI-T is 5 stars and the best meter out there.    :-DD

It's a bit over half way now.  Do you think the contacts are wearing as good at the Brymens?  Think it will out perform the Fluke 17B+, after all this is a + model too!


Someone had asked about the life of the test fixture.  It's a direct drive stepper stuck in a PanaVise, with an aluminum fork  mounted to the end.  The only wear would be the stepper's two ball bearings.   The software adjusts the motor's torque while learning the meter.  The meter's present basically no load to the stepper.   I looked at the manuals and did not find any MTBF data.  4 year warranty.     
Title: Re: Handheld meter robustness testing
Post by: Per Hansson on October 08, 2021, 04:47:25 pm
What a difference a day makes.   It has a long way to go...
Haha, perfect for a quiet lab, it's so silent now!  :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 08, 2021, 11:16:09 pm
Into day 3 of the life cycle.  I wonder if there is anything left of the PCB or contacts. 

The UNI-T uses grease on the contacts where the 17B+ was dry.  Surely the grease will make the UNI-T outperform the Fluke.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 09, 2021, 12:53:46 am
Into day 3 of the life cycle.  I wonder if there is anything left of the PCB or contacts. 

The UNI-T uses grease on the contacts where the 17B+ was dry.  Surely the grease will make the UNI-T outperform the Fluke.
I forgot: you constantly evaluate the staus of the contacts during the ordeal, right?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 09, 2021, 01:01:06 am
Yes, it's being recorded.  Like before, I will compare this new data against the others I have looked it.
Title: Re: Handheld meter robustness testing
Post by: floobydust on October 09, 2021, 05:24:13 am
Uni-T did a ripoff of the Fluke rotary switch patent US8946571 (https://patents.google.com/patent/US8946571B2/en) and US8093516 (https://patents.google.com/patent/US8093516B2/en), as far as the detents, teeth and spring...  copied. So it should work just as good  ;)  minus the nickel-plated beryllium copper...
It looks like there are still a few via's on the rings contact path though.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 09, 2021, 12:12:37 pm
Uni-T did a ripoff of the Fluke rotary switch patent US8946571 (https://patents.google.com/patent/US8946571B2/en) and US8093516 (https://patents.google.com/patent/US8093516B2/en), as far as the detents, teeth and spring...  copied. So it should work just as good  ;)  minus the nickel-plated beryllium copper...
It looks like there are still a few via's on the rings contact path though.

I have no doubt that some of the UNI-T fanboys would actually believe the UNI-T UT61E+ is every bit as good as the Fluke 87V in every way.  They are just lower cost is all.  And, if you happen to own an 87V, you're considered a snob.   :-DD  :-DD :-DD  It does say something about the market UNI-T targets.   

50,000 full cycles on the clock when I woke up.

***
Inspecting the UT61E+ under the frankenscope. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 09, 2021, 10:22:22 pm
UT61E+ life cycle test.

https://www.youtube.com/watch?v=eUtdnspgZec (https://www.youtube.com/watch?v=eUtdnspgZec)
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on October 10, 2021, 06:55:09 am
Into day 3 of the life cycle.  I wonder if there is anything left of the PCB or contacts. 
...

So in summary, the contacts and the PCB traces survived the 50,000 cycles in relatively good shape, the (nylon?) spring lobes were slightly worn out and the two small endstop plastic posts broke off, which you "repaired" in less than 15 minutes.

Wouldn't it be correct to point out that 50,000 rotary switch endstop-to-endstop cycles correspond to > 20 years of daily normal use for any of us here?
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 10, 2021, 08:15:23 am
Wouldn't it be correct to point out that 50,000 rotary switch endstop-to-endstop cycles correspond to > 20 years of daily normal use for any of us here?

I think it would be far more correct to point out that:
a) The little posts snapped off much sooner.
b) The meter stopped working right after they snapped off (see contact resistance graphs)
c) The dial stopped making a clicking sound after they snapped off which means it wasn't turning the white part of the selector properly.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 10, 2021, 12:11:13 pm
Well, the meter survived quite well the torture - thanks for doing this.

A few unknowns, especially due to the dramatic self-healing, but that happened with the other meters as well.

After 50k the status of its contacts and PCB are quite interesting. No way to compare with the 17B+, but still...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 10, 2021, 03:13:51 pm
So in summary, the contacts and the PCB traces survived the 50,000 cycles in relatively good shape, the (nylon?) spring lobes were slightly worn out and the two small endstop plastic posts broke off, which you "repaired" in less than 15 minutes.

With the wiper contacts not fully rotating, they and the PCB were not subjected to the same level of testing other meters endured.   I have no idea how long it would take to repair the meter but if I were trying to use the meter and these pins snapped, it would have gone to the trash as the meter can't be trusted.  Would I just happen to have a soldering iron, some scrap plastics and other tool need to repair the meter with me at the time, I doubt it.  The delay in the test could be much longer.   Then again, who is going to trust using a UNI-T product for something that is time and data critical...   

Wouldn't it be correct to point out that 50,000 rotary switch endstop-to-endstop cycles correspond to > 20 years of daily normal use for any of us here?
We talked about this early on.  Similar to the transient testing, it evolved.  If you watch the very first video where I proposed running this test, I was looking at 2000 cycles and was not monitoring the resistance.     Someone posted an ad for a UNI-T meter that was rated for 30,000 cycles on the switch. 

https://www.eevblog.com/forum/testgear/finally-received-my-uni-t-ut17b-pro-im-pleasantly-surprised/msg3180548/#msg3180548 (https://www.eevblog.com/forum/testgear/finally-received-my-uni-t-ut17b-pro-im-pleasantly-surprised/msg3180548/#msg3180548)

b) The meter stopped working right after they snapped off (see contact resistance graphs)

Technically yes, but misleading.  No doubt that the pins breaking is a failure and makes the meter unusable.   I have no idea how many cycled were on the meter when the pins broke or how it correlates with the contact resistance.  What we can see is that the contact's resistance  was opening up at 5700 cycles.     No doubt that when the pins broke it limited the movement of the wiper contact.   
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on October 10, 2021, 03:26:15 pm
...
With the wiper contacts not fully rotating, they and the PCB were not subjected to the same level of testing other meters endured.
...
No doubt that when the pins broke it limited the movement of the wiper contact.

So, the 50,000 cycles "torture test" is to be considered inconclusive with regards to wear of the PCB and contacts?
And would you say the two small plastic pins/post broke of because your test bed setup was hitting the end stops thousands of times?
Does that correspond to a real use case?

It seems you concluded in the video that the UT61E+ is "more robust" than the discontinued UT61E, but that's not saying much, is it?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 10, 2021, 03:32:04 pm
Well, the meter survived quite well the torture - thanks for doing this.

For a UNI-T product, overall, I couldn't agree more but not when compared with the better brands I have looked at. 

Then again, having the meter modified may have saved it from the total destruction we are use to seeing with this brand.  It's not good enough for me to want to invest more time into looking at the brand again.   After 13 products, I think we have learned our lesson. 

Quote
A few unknowns, especially due to the dramatic self-healing, but that happened with the other meters as well.

Well, let's be clear.  If we are talking about the contacts opening up (>1kohm) some meters have self healed.  Cycle3 shows the five worse meters I have looked at.  All of these went open before 7000 cycles.  It's good to see Keysight in the mix with UNI-T and the free HF meter.   :-DD   

But consider the other five meters in Cycle4.  None of these meters ever opened up during the entire duration of the test.  Note that even Dave's 121GW with it's cobbled switch and countless contacts hung in there.    While Dave's test limited the measurement to 10 ohms, I like being able to see the higher values and trusting the HP bench meter.   

Quote
After 50k the status of its contacts and PCB are quite interesting. No way to compare with the 17B+, but still...

True but again, the wiper contacts were not locked to the knob.   How would the meter have held up had the pins not broke?  What if they hadn't spec'ed the frequency counter to 200MHz and the meter still had the original components?  Would a small ESE event have damaged it? 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 10, 2021, 03:58:52 pm
...
With the wiper contacts not fully rotating, they and the PCB were not subjected to the same level of testing other meters endured.
...
No doubt that when the pins broke it limited the movement of the wiper contact.

So, the 50,000 cycles "torture test" is to be considered inconclusive with regards to wear of the PCB and contacts?
And would you say the two small plastic pins/post broke of because your test bed setup was hitting the end stops thousands of times?

During the video, I demonstrate how the torque is adjusted before starting the test, slowly reducing it until the motor stalls (slips).   The torque is then increase a small amount and this is used for the remainder of the tests.  The video then shows how the software then searches for the dead stops.  It then limits the range of rotation within a few degrees.   

Quote
Does that correspond to a real use case?
How would we know?  There is a big difference between the guy taking the meter out of a drawer twice a year to look at some clock batteries and someone working as a professional in an industry were the meter is in constant use. 

I would not be surprised if most users would turn the knobs to their dead stops with far more force than I subject them to.  But then I would not be surprised if most UNI-T products are not used in a professional environment and see minimal use compared with what I am demonstrating.   I loaned out my CEM meter to someone who forced it beyond the dead stops.  It's one of the weak points of that particular meter.  I guess that was real world.

Quote
It seems you concluded in the video that the UT61E+ is "more robust" than the discontinued UT61E, but that's not saying much, is it?
Yes, discontinued but still available for purchase brand new.   And yes, 61E+ more robust after mods than the stock UT61E.   From the factory, I have no idea.   
***
SP
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 10, 2021, 04:26:04 pm
Joe, do you know which are the plastics paired in this meter? (The white spring, and the dark one it rubs on.)
And in the Keysight?

If we have the angle of the half rotation(from off to full stop to the right), and the angle of wobble of the wiper pad without the two pins, than we have to double this second value (if we suppose that the wipers were not moving at all while in a "floating position) and deduce the value from the full angle of the rotation.
It can be that the switch had actually 30% or even less rubbing movement than it would normally had without the pins broken.

Edit:
If I remmber right not even the Brymen is using plain PA6 for the case. Is that because of the possibility of picking up water?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 10, 2021, 06:16:50 pm
I am not a materials engineer and have no idea what they are using.  The Keysight appears to be a glass filled material. 

For the rubbing movement, lol... yes the detent spring will move with the knob once it hits the knobs dead stops (not referring to the dead stop in the case).   The ends of the rotation will have less rubbing movement than the center.  I would have no idea how much less as I am not sure when the pins broke.  With the contacts moving to a different location, it will effect the resistance measurement.
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on October 10, 2021, 07:18:54 pm
Joe, do you know which are the plastics paired in this meter? (The white spring, and the dark one it rubs on.)
And in the Keysight?
...

Like Joe, I am not a material/plastics engineeer, but I believe in the UT61E+ the white spring is nylon, whereas the dark plastic it rubs on is polycarbonate.

https://en.wikipedia.org/wiki/Nylon

https://en.wikipedia.org/wiki/Polycarbonate#Applications

Title: Re: Handheld meter robustness testing
Post by: Fungus on October 10, 2021, 07:42:58 pm
A chain is only as good as the weakest link. It turned out that the wipers and PCB weren't the weakest link here, but so what? The meter broke in a way that would have most people throwing it away.

It's bad design. The physical integrity of the dial depends on two small posts for no good reason - the posts could easily be made much bigger for zero additional cost.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 10, 2021, 08:44:05 pm
I agree with fungus on this one.   It's better to just buy products that meet your needs.  This meter isn't something I would use but it could be a very good fit for someone else.  I would assume the pin breaking problem was known as someone had left a comment about it.

If this meter could survive the transients from the factor, they stopped with the false ads (freq counter), improve the mechanical design and lowered the price.....   

Do you know how many meters I say something similar about?  Every single one of them!!   :-DD   
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on October 10, 2021, 10:22:20 pm
...
It's bad design. The physical integrity of the dial depends on two small posts for no good reason - the posts could easily be made much bigger for zero additional cost.

Yet again, that's your "armchair expert" opinion from watching Joe's video. It holds as much value as the two plastic posts that broke off...  :palm:

You should try devising your own test procedures, and building your own testing apparatus, and accumulating a few years of experience, because that's where the value of Joe's videos lies, as I am sure you realize?
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 10, 2021, 10:49:00 pm
Well, the meter survived quite well the torture - thanks for doing this.

For a UNI-T product, overall, I couldn't agree more but not when compared with the better brands I have looked at. 

Then again, having the meter modified may have saved it from the total destruction we are use to seeing with this brand.  It's not good enough for me to want to invest more time into looking at the brand again.   After 13 products, I think we have learned our lesson.
Indeed. The transient test could have swayed you out of the switch test a lot earlier in the process. However, as we stand today, the state of the contacts and PCB held much better than the other single-test brands you did (apart from UEI, of course).

The break of the stands is an unfortunate event that muddles the waters, so it prevents us from saying one way or another: i.e., that UT61E+ has a crap switch or an "above average" one.

A few unknowns, especially due to the dramatic self-healing, but that happened with the other meters as well.

Well, let's be clear.  If we are talking about the contacts opening up (>1kohm) some meters have self healed.  Cycle3 shows the five worse meters I have looked at.  All of these went open before 7000 cycles.  It's good to see Keysight in the mix with UNI-T and the free HF meter.   :-DD   

But consider the other five meters in Cycle4.  None of these meters ever opened up during the entire duration of the test.  Note that even Dave's 121GW with it's cobbled switch and countless contacts hung in there.    While Dave's test limited the measurement to 10 ohms, I like being able to see the higher values and trusting the HP bench meter.
Indeed they didn't open, although the cheapest of the bunch (17B+) was the only one completely unfazed during the test cycle. Also, they are Shift-left the price of an UT61E+ (apart from the Keysight, of course), so there is something to be said about bang per buck (something I also commented on Youtube - didn't read yet your reply there).

After 50k the status of its contacts and PCB are quite interesting. No way to compare with the 17B+, but still...

True but again, the wiper contacts were not locked to the knob.   How would the meter have held up had the pins not broke?  What if they hadn't spec'ed the frequency counter to 200MHz and the meter still had the original components?  Would a small ESE event have damaged it?
Yes, the breakoff was quite unfortunate and we don't know when this happened in the test. If they indeed copied Fluke's patent as mentioned by floobydust above, they skimped on materials or were incompetent in their redesign.

As for the other specs, that is my biggest beef with Uni-T, Aneng and others: they lie through their teeth with regards to CAT ratings (and, in this particular case of the Uni-T, specifications themselves). If they slap a CAT II 300V on their gear, I would have much more respect for them.

Full disclaimer, I have a Uni-T and a pair of Agilents and they are so far holding well while being used with certain regularity for the best part of five or six years - nowhere near 50k operations, obviously. As I mentioned many times before, the Fluke 87V and 179 rotary switches are kings to me: they are the sturdiest and most well put together that I have ever seen. Unfortunately I don't have the capex to put my Agilent meters through a similar torture contraption as I need them for various tasks and, as you could well see, youtube videos do not bring enough revenue to justify such adventure.  :-DD

Overall, thanks again for doing the test and publishing these results. That is a great advancement for the manufacturers.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 11, 2021, 12:39:49 am
Quote
However, as we stand today, the state of the contacts and PCB held much better than the other single-test brands you did (apart from UEI, of course).

It's similar to how Fungus would comment how a meter that was tested at 1kV and survived but then failed it 20kV with no other data collected between, didn't fail until 20kV.   While technically true, it's very miss leading.    You are also 100% correct.  The switch broke early on in the testing.  We've seen the contacts open up and a broken detent spring but we've never seen a design so poor that the contacts fail to turn with the knob.  And yes, the PCB and contacts were spared.       

Quote
... as you could well see, youtube videos do not bring enough revenue to justify such adventure.
  :-DD :-DD
I have yet to beg for subscribers or $$$.   If we run another UNI-T, I may have to start a go fund me account.  Not to cover the cost of the meter or the time to run it but for pain and suffering.   :-DD :-DD 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on October 11, 2021, 01:05:58 am
Quote
However, as we stand today, the state of the contacts and PCB held much better than the other single-test brands you did (apart from UEI, of course).

It's similar to how Fungus would comment how a meter that was tested at 1kV and survived but then failed it 20kV with no other data collected between, didn't fail until 20kV.   While technically true, it's very miss leading.    You are also 100% correct.  The switch broke early on in the testing.  We've seen the contacts open up and a broken detent spring but we've never seen a design so poor that the contacts fail to turn with the knob.  And yes, the PCB and contacts were spared.
I suspect you understood my statement, but let me clarify anyways: I wasn't closing the case on the meter's quality, but only on the evidence we could gather from the (unfortunately) imprecise test.

Well, that and perhaps a way to tickle your nerve and see if you would be swayed to run another UT61E+ (or another meter from them) in the future. Judging by your next statement, I now know you have a price... :-DD 

Quote
... as you could well see, youtube videos do not bring enough revenue to justify such adventure.
  :-DD :-DD
I have yet to beg for subscribers or $$$.   If we run another UNI-T, I may have to start a go fund me account.  Not to cover the cost of the meter or the time to run it but for pain and suffering.   :-DD :-DD
Just to clarify, I have never asked to hit like or subscribe... Perhaps if I have done that (and created my videos in a language almost as common as Klingon) I could have made enough to splurge on another U1282A to be tortured. :-D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 11, 2021, 02:58:40 am
I suspect you understood my statement, but let me clarify anyways: I wasn't closing the case on the meter's quality, but only on the evidence we could gather from the (unfortunately) imprecise test.

Well, that and perhaps a way to tickle your nerve and see if you would be swayed to run another UT61E+ (or another meter from them) in the future. Judging by your next statement, I now know you have a price... :-DD 

The only thing we learned from that test was the switch is poorly designed but expected based on the previous 12 products we looked at. 

I assumed my comment about a fund me would be understood as sarcastic.   I had no interest in looking at another UNI-T product but I caved to peer pressure of viewers.   :-DD

I may be persuaded to look at another UNI-T product in the future but there would be no reason to look at another 61E+ unless it was improved.   Had the two posts not snapped, I was going to get a second one to repeat the transient tests but like fungus, I think the meter has too many weak links in the design to make it worth spending any more resources on.       

Just to clarify, I have never asked to hit like or subscribe... Perhaps if I have done that (and created my videos in a language almost as common as Klingon) I could have made enough to splurge on another U1282A to be tortured. :-D

Don't forget the bell and turn on ads.   It all helps.    I would have to get the Fluke yellow Keysight meter. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 11, 2021, 05:01:01 am
It's better to just buy products that meet your needs.  This meter isn't something I would use but it could be a very good fit for someone else. 

The only thing I see this meter has going for it is the PC connection.

As a standalone meter? Nope. For the same money I can get a 20,000 count Aneng and a Fluke 101.
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 11, 2021, 06:56:44 pm
I am not a materials engineer and have no idea what they are using.  The Keysight appears to be a glass filled material. 

Its often marked on the plastic with a few letters, so you don't necessarily have to throw it into a gas chromatograph. Glass fibre in that arrangement, does not seems to be good idea anyway, but it did not got so far to rub off the plastic.
Joe, do you know which are the plastics paired in this meter? (The white spring, and the dark one it rubs on.)
And in the Keysight?
...

Like Joe, I am not a material/plastics engineeer, but I believe in the UT61E+ the white spring is nylon, whereas the dark plastic it rubs on is polycarbonate.

https://en.wikipedia.org/wiki/Nylon

https://en.wikipedia.org/wiki/Polycarbonate#Applications


The white stuff is usually POM. which stands probably for Polyoxymethylene Of Her Majesty.

I will check the Brymen later on, if it has letters on the parts.

Just wondering if any of the expensive meters are actually using teflon.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 13, 2021, 11:06:48 am
Its often marked on the plastic with a few letters, so you don't necessarily have to throw it into a gas chromatograph. Glass fibre in that arrangement, does not seems to be good idea anyway, but it did not got so far to rub off the plastic.

I would imagine that if all four prongs of the Keysight meter's detent spring hadn't fractured, it would have eventually started to cut into the case.  But they broke really early on in the cycling. 
Title: Re: Handheld meter robustness testing
Post by: AndrewBCN on October 13, 2021, 12:23:22 pm
...
The white stuff is usually POM. which stands probably for Polyoxymethylene Of Her Majesty.
I will check the Brymen later on, if it has letters on the parts.
Just wondering if any of the expensive meters are actually using teflon.
I believe POM is too stiff to be used as a plastic "spring" part, but in any case, the only way to be 100% certain about what plastics are used for the various parts in any multimeter or electronic test equipment is to get the information straight from the manufacturer, iow next to impossible (unless there are markings on the case, as you suggested).

PTFE (one of the variants of Teflon) is a very good plastic for certain applications in electronic test equipment, but it is also very expensive. https://en.wikipedia.org/wiki/Polytetrafluoroethylene

About the symbols on plastic parts: https://en.wikipedia.org/wiki/Resin_identification_code
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 14, 2021, 02:53:30 pm
Its often marked on the plastic with a few letters, so you don't necessarily have to throw it into a gas chromatograph. Glass fibre in that arrangement, does not seems to be good idea anyway, but it did not got so far to rub off the plastic.

I would imagine that if all four prongs of the Keysight meter's detent spring hadn't fractured, it would have eventually started to cut into the case.  But they broke really early on in the cycling.

Possibly a very well designed safety feature from Keysight, which saves the case from being damaged. :)

Now I checked the Brymen 789: No markings on the plastic, except the upper case which is made of Policarbonate. On the lower case the letters are erased.
Interesting is, that now after not much usage, the wearmarks on the traces have a silverish colour. Checked your video again, but was unable to find out what the colour there was. It looks like as if wipers had some silverish material under the gold coloured.

For me by the way the rotary switch of the dt830 meters gives the best feeling, and if I consider the latching mechanism with the steel balls, I am quiet sure that this part of the mechanic would survive the torture test. Not necessarily the wipers of course.
Never felt the Gossen though...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 14, 2021, 04:30:45 pm
I had ran a that DT830 which of course had failed very early on.  It's the only meter that was so bad, I aborted the test. 

Somewhere there are pictures and a video showing how the ball had cut a deep grove into the case. 
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 14, 2021, 04:40:32 pm
I checked your youtube channel but found only short videos to the dt830. Is it one of them?

Anyway rather interesting, because in theory this construct should be quiet robust. With some non silicon grease I would have guessed it to outlast all the other meters. But maybe the plastic is so shitty that it's still not enough. Mine is also broken because of a very short fall.

Still the best switch-feeling to me.   ;D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 14, 2021, 05:42:04 pm
Should be one of the very early ones.  The contacts opened up several traces and there was little left of the plastic.  I repaired the meter and used it for another test.   Maybe took it out with ESD.   
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 17, 2021, 11:33:13 am
Found it.
Did you ever run the ut-210e with the generator, or the grill starter? Because the protection seems to be reasonable, at least compared with other Uni-t's.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 17, 2021, 03:15:12 pm
I've only looked at the meters included on the spreadsheet.  I would have no reason to plug the leads into the UT210E.  I kept it for that 1mADC resolution.       

There's not much room on the inside.  I would imagine it would do about as well as the other 13 UNI-T products I have looked at. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 17, 2021, 06:59:21 pm
I would have no reason to plug the leads into the UT210E.

There's not much room on the inside. I would imagine it would do about as well as the other 13 UNI-T products I have looked at. 

This page has photos of the insides. Everything is very close together and there's still no surge resistor on the input.

https://lygte-info.dk/review/DMMUNI-TUT210E%20UK.html

It only claims CAT III 300V, CAT II 600V which is a very low standard. I guess it might meet those numbers.

the protection seems to be reasonable, at least compared with other Uni-t's.

If you're confident in the protection you can do a grill starter test at home. Grill starters are cheap and easy to find.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 17, 2021, 09:10:25 pm
....
Grill starters are cheap and easy to find.

But not all the same!!
Title: Re: Handheld meter robustness testing
Post by: Fungus on October 18, 2021, 03:12:59 am
Maybe one of those electric fly swatters would be a good test, too.  :)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 18, 2021, 12:54:58 pm
Or just leave the probes out of it.  Of course, the switch will still fail.
Title: Re: Handheld meter robustness testing
Post by: floobydust on October 19, 2021, 07:20:19 pm
I don't like the UT61E+ LCD conking out with the BBQ lighter hits. I'd say it's got an EMC issue or the clamp-transistors have too high an avalanche voltage, usually around 7V some parts are even 12-25V. And what good are they anyhow if the IC is running off 3.6V, it's still getting nailed.

It would be interesting to compare the current of the BBQ lighter to 61000-4-2 ESD models, like the 150pF/330Ω  or 1,000pF hits.
Is the metal box (blast shield) earth grounded? I thought stray capacitance with the multimeter's foil shield could lessen the spike. Uni-T has no shield on the front side?
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 21, 2021, 05:31:00 pm
I would have no reason to plug the leads into the UT210E.

There's not much room on the inside. I would imagine it would do about as well as the other 13 UNI-T products I have looked at. 

This page has photos of the insides. Everything is very close together and there's still no surge resistor on the input.

https://lygte-info.dk/review/DMMUNI-TUT210E%20UK.html

It only claims CAT III 300V, CAT II 600V which is a very low standard. I guess it might meet those numbers.

the protection seems to be reasonable, at least compared with other Uni-t's.

If you're confident in the protection you can do a grill starter test at home. Grill starters are cheap and easy to find.

Not that confident, but still interested. Does it have protection diode clamps? If so I would bet it survives up till about ...4000V. But mabe not the grillstarter.
I "tested" it once with about 1000 V Dc , but it was only an insulation tester.

Joe in one thread you mentioned measuring a welding inverter with it, after which in was only reading OL.
Did you use the clamp to measure the amps? What exactly caused the damage?


Title: Re: Handheld meter robustness testing
Post by: joeqsmith on October 25, 2021, 10:14:25 am
I would have no reason to plug the leads into the UT210E.

There's not much room on the inside. I would imagine it would do about as well as the other 13 UNI-T products I have looked at. 

Joe in one thread you mentioned measuring a welding inverter with it, after which in was only reading OL.
Did you use the clamp to measure the amps? What exactly caused the damage?

Read the following post:
https://www.eevblog.com/forum/testgear/over-current-in-clamp-meter/msg1996529/#msg1996529 (https://www.eevblog.com/forum/testgear/over-current-in-clamp-meter/msg1996529/#msg1996529)
Title: Re: Handheld meter robustness testing
Post by: Neutrion on October 25, 2021, 03:42:05 pm
Oh, thanks, this was also my first guess. Don't no if it is actually possible to damage the sensors on the clamp. Which according to a long youtube video of a german guy, are actually not hall sensors if I remember right. (In the two piece long videos about the calibration and working principles...)
Title: Re: Handheld meter robustness testing
Post by: Nisei on January 09, 2022, 04:30:36 am
Also the pictures of the discontinued UT61E that Fungus posted are from another EEVblog forum member Nisei, who duly noted (as can be seen on the PCB silk screen) that the two UT61E DMMs that he owns are different variants of the UT61E - the model on the left is a UT61E-GS and indeed it has better input protection and larger fuses.
Show me a photo of a Uni-T meter, a manual, or a website link that actually has a meter labelled "UT61E-GS".
Sorry, just noticed this and feel like I have to step in to clarify the picture I've posted (even if it's been ages ago) which is being re-used in this thread.
Sucks when you don't get notified when people repost stuff but that's inevitable.
I have no time to read all the posts following that post but here's what was going on:
Reichelt (a German distributor) wanted to sell this meter in Europe but they knew the ratings were bogus so they asked Uni-T to alter some things and had it recertified.
Hence the input protection being beefed up and the CAT ratings being lowered.
Only then could it get a German GS rating.
I believe it was a one-off order of umpteen thousand and when they were sold that was it (no idea how many) because even when the regular 61E was in production they were already sold out.
I still haven't blown it up  :-X
Title: Re: Handheld meter robustness testing
Post by: cybercorfu on January 10, 2022, 02:17:54 am
I would like to ask the community I have UT181a not long but the battery drains very quick I measure the current when off to 18mA is this normal?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 10, 2022, 12:42:07 pm
I would like to ask the community I have UT181a not long but the battery drains very quick I measure the current when off to 18mA is this normal?

I've left the meter off for months at a time and haven't noticed a problem.   How did you measure the current?  If the meter is new, why didn't you return it under warranty?

Title: Re: Handheld meter robustness testing
Post by: cybercorfu on January 11, 2022, 07:38:36 pm
Its used bought it from ebay I cut positive cable from battery and made the measurement
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 12, 2022, 01:47:00 pm
When I measured the battery life, I think I just clipped onto the meters connector.   
Title: Re: Handheld meter robustness testing
Post by: cybercorfu on January 12, 2022, 11:06:12 pm
Is it possible for a faulty MOSFET ?  It really annoying not using the meter and trying to power it on and needs changing
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 13, 2022, 12:21:41 am
You would need to trace that section out and track down the high leakage path.   I had started to look at that area after I damaged mine.   It seemed to use all jellybean parts so shouldn't be too difficult to repair.   With that being a weak area, I wonder if yours was subjected to a small transient as well. 
Title: Re: Handheld meter robustness testing
Post by: cybercorfu on January 13, 2022, 11:42:14 pm
Remove AIQ5VA IC and the current dropped to 1mA I've made an order and we see... I think maybe ever make an external charging port straight to battery with a protection circuit for logging perposes and drop the whole IC for charging unable to use meter...
Title: Re: Handheld meter robustness testing
Post by: cybercorfu on January 14, 2022, 08:41:02 am
It does seem high a few μA OK but a mA it high
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on January 14, 2022, 10:42:43 am
Doesn't a mA seem high?

Especially when you consider the shunt resistance... take that out of circuit and it's going to be even higher.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 14, 2022, 11:42:17 am
Doesn't a mA seem high?

Especially when you consider the shunt resistance... take that out of circuit and it's going to be even higher.
Sure, the current most likely would get higher but is it really worth pointing out?    I had asked them how they measured the current but not being there, I really have no idea outside of the cut wire.   I don't know anything about the circuit but it could very well be acting as a constant current sink.   They would need to supply more data.  Still it's a 7ish volt battery.  Even with a 100 ohms, at a mA your talking 100mV of drop.   Under a percent error.  I would think they would be using an amplified shunt without a fuse but who knows. 
Title: Re: Handheld meter robustness testing
Post by: cybercorfu on January 14, 2022, 01:49:51 pm
Under constant observation the current leakage stabilized at 95μA maybe its the RTC and XTAL that's fine I guess...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 14, 2022, 03:10:28 pm
Under constant observation the current leakage stabilized at 95μA maybe its the RTC and XTAL that's fine I guess...

I'll measure mine when I have some time today and let you know.  While mine was damage, later repaired and then modified, I doubt there was any effect on the current draw.   Should at least provide you with some idea how low it should be.   As I said, mine will sit for months at a time and not discharge. 
Title: Re: Handheld meter robustness testing
Post by: Grandchuck on January 14, 2022, 03:17:21 pm
Under constant observation the current leakage stabilized at 95μA maybe its the RTC and XTAL that's fine I guess...

As I said, mine will sit for months at a time and not discharge.

Same here.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 15, 2022, 12:06:27 am
I measure about 37.4uA with 7.5V.   
Title: Re: Handheld meter robustness testing
Post by: ilkinandr92 on January 22, 2022, 07:14:54 am
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD

Correct.

I mean, seriously, what is the point of testing the UT61E for "robustness"? We all know it isn't.
At first glance yes. The UT61E (and probably the UT61E+) are finicky with transients but why not put it through its paces? Who knows? Perhaps it could be an additional advantage of the "plus" model...

Looking at the data I've collected,  of the eight UNI-T products I looked at, half never made it past the ESD, AC line tests.    During the EEVBLOG review for the 61E+, Dave focuses on the lack of a surge rated resistor.   The UT181A is the same and survived some decent hits after a few small changes.    Dave talks about the new ground path.   It could help but my guess is it won't.   

Obviously that the "real" test would be with the "third party plus-certified and mega-accredited and über-listed" UT161E, but that is in another price league...

That meter would fail ESD just like the stripped down version.   

At any rate, I don't think there is much to be lost, especially after you already beaten to death the UT61E original, with excellent suggestions to increase its robustness.

For you, skim the video for a few seconds and your done.    Flip side, it takes fair amount of my time to run the tests and edit the videos.  For this meter, assuming the grill starter kills it, maybe six days.   Half of that would be cycling the function switch.   
 

(edit) Kerry Wong also did a teardown of the UT61E+
http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/ (http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/)

(edit2) Tenma has some discounts on beefed up UT61E (non plus)
https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/ (https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/)

Skimmed the Kerry Wong video but didn't notice anything beyond what Dave had gone over. 

We could reorder the tests for this special meter.  Start with the 100us transients.  If it survives  that (which it won't) then run the AC line test and then the ESD.  Not sure we would learn anything more doing this.  The end results the same. 

UNI-T fanboys are already thinking I am biased against this meter.  I can see the mass of down votes. lol.  I have more than enough data now to know what to expect.

Hi,
I know this is reopening an old topic, but I would love to see how UT161E would fair in your tests.
I was able to find a video of UNI-T UT161E and UNI-T UT61E+ that shows some differences.
He mentions that there is some modification at the top part of the PCB.
https://www.youtube.com/watch?v=lbIg6YrkAG0 (https://www.youtube.com/watch?v=lbIg6YrkAG0)
https://www.aliexpress.com/item/1005002717433552.html?spm=a2g0s.8937460.0.0.73f02e0eghZUfO (https://www.aliexpress.com/item/1005002717433552.html?spm=a2g0s.8937460.0.0.73f02e0eghZUfO)
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 22, 2022, 08:18:07 am
Hi,
I know this is reopening an old topic, but I would love to see how UT161E would fair in your tests.

Why? If robustness is a big concern then you can buy a proper multimeter for that much money.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 22, 2022, 03:23:02 pm
https://www.uni-trend.com/meters/html/product/General_Meters/Digital_Multimeters/UT61%20161%20Series/UT161E.html (https://www.uni-trend.com/meters/html/product/General_Meters/Digital_Multimeters/UT61%20161%20Series/UT161E.html)

Frequency (Hz)    220MHz    ±(0.01%+5)

Note the lack of anything to limit the current if I attempt it.  I suspect we would see another meltdown if I were to attempt to test this feature.     Of course, we could just ignore it like the UNI-T fan boys suggested.   

Skimming the video, they have larger fuses which makes no difference in the data I collect.  The voltage path looks the same.  After damaging its little brother, I beefed up the clamp.   This meter wouldn't have that luxury and would most likely not hold up as well.   



That channel is getting close to 20k subscribers.  Like when it hit 2k, it seems like we should have a look at something special if it ever makes it up that high.   Last time we had a lot of fun with a high end Gossen.   
Title: Re: Handheld meter robustness testing
Post by: ilkinandr92 on January 22, 2022, 10:47:18 pm
Hi,
I know this is reopening an old topic, but I would love to see how UT161E would fair in your tests.

Why? If robustness is a big concern then you can buy a proper multimeter for that much money.

161E goes on sale for $56 at times, if you can recommend anything better that has same features or more I'm open to suggestions.
 I am not electrician, I am just looking to get something that is best bang for the buck and the better the protection the better. I only plan to use it for anything as small electronics to 240v 3 phase machines my dad has at his shop.
My other option is Brymen BM789 but I didnt want to spend that much and not sure how the warranty would even work on it, when its imported to US.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 22, 2022, 11:50:51 pm
And how does the warranty work on the UNI-T in the USA?   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on January 23, 2022, 01:15:15 am
And how does the warranty work on the UNI-T in the USA?
You can get warranty in the US for a "Uni-T like" by paying a steep premium from Farnell:
https://www.newark.com/multicomp-pro/mp730679/dmm-true-rms-20a-1kv-22000-count/dp/64AJ4559?st=Tenma%20multimeter (https://www.newark.com/multicomp-pro/mp730679/dmm-true-rms-20a-1kv-22000-count/dp/64AJ4559?st=Tenma%20multimeter)

Terribly expensive for what it is. Even their old UT61E models do not have the promotional price anymore.
https://www.newark.com/tenma/72-10415/dmm-hh-10a-1kv-22000count/dp/94AC6580?st=Tenma%20multimeter (https://www.newark.com/tenma/72-10415/dmm-hh-10a-1kv-22000count/dp/94AC6580?st=Tenma%20multimeter)

My other option is Brymen BM789 but I didnt want to spend that much and not sure how the warranty would even work on it, when its imported to US.
As for Brymen in the US with warranty, Greenlee would be the brand to go. They don't have a BM789, but a BM869 instead. Paying a bit more than the originals, but it is the real deal. I just got a brand new DM200A (BM251S) on an eBay bargain (half of a UT61E+) and it is incredibly compact and well built, even features premium gold leads. :-+
Title: Re: Handheld meter robustness testing
Post by: ilkinandr92 on January 23, 2022, 01:45:39 am
And how does the warranty work on the UNI-T in the USA?
You can get warranty in the US for a "Uni-T like" by paying a steep premium from Farnell:
https://www.newark.com/multicomp-pro/mp730679/dmm-true-rms-20a-1kv-22000-count/dp/64AJ4559?st=Tenma%20multimeter (https://www.newark.com/multicomp-pro/mp730679/dmm-true-rms-20a-1kv-22000-count/dp/64AJ4559?st=Tenma%20multimeter)

Terribly expensive for what it is. Even their old UT61E models do not have the promotional price anymore.
https://www.newark.com/tenma/72-10415/dmm-hh-10a-1kv-22000count/dp/94AC6580?st=Tenma%20multimeter (https://www.newark.com/tenma/72-10415/dmm-hh-10a-1kv-22000count/dp/94AC6580?st=Tenma%20multimeter)

My other option is Brymen BM789 but I didnt want to spend that much and not sure how the warranty would even work on it, when its imported to US.
As for Brymen in the US with warranty, Greenlee would be the brand to go. They don't have a BM789, but a BM869 instead. Paying a bit more than the originals, but it is the real deal. I just got a brand new DM200A (BM251S) on an eBay bargain (half of a UT61E+) and it is incredibly compact and well built, even features premium gold leads. :-+

I wouldn't care much about 161e warranty for $50-60 price.
I was looking at BM869s but it's too bulky and expensive than even 789. DM200A Looks nice but limited features and small counter.
Got anything close to 161e feature wise, better protection around $100?
If not, would 161e be safe while working on 240v 3 phase machines? I would mod it to make it more robust but not electrical engineer, and I know it's not allowed to ask for help with that here sadly.
Appreciate the help.
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 23, 2022, 07:26:17 am
Got anything close to 161e feature wise, better protection around $100?

For that money you can get a decent Zoyi (https://www.aliexpress.com/wholesale?catId=0&SearchText=zoyi+vc17b) and a Fluke 101. Two meters is always more useful than one and you can poke at your mains power with the Fluke.

The only excuse I can think of for buying that Uni-T is the PC data connection. Nothing else about it says "This is worth the money!" (IMHO).

161E goes on sale for $56 at times, if you can recommend anything better that has same features or more I'm open to suggestions.

If you really want the Unit-T then get one at that price plus a Fluke 101. For the same reasons given above.
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 23, 2022, 07:50:43 am
If not, would 161e be safe while working on 240v 3 phase machines?

No meter is 100% "safe" because there's always operator error. There's also a couple of pages now that are telling you that it's probably no better than the ordinary 61E, ie. the extra '1'  in the name is mostly marketing.fluff to sell (practically) the same meter for more money.

The Fluke 101 is about as close as any meter gets to "safe" in untrained hands.
Title: Re: Handheld meter robustness testing
Post by: ilkinandr92 on January 23, 2022, 08:15:25 am
If not, would 161e be safe while working on 240v 3 phase machines?

No meter is 100% "safe" because there's always operator error. There's also a couple of pages now that are telling you that it's probably no better than the ordinary 61E, ie. the extra '1'  in the name is mostly marketing.fluff to sell (practically) the same meter for more money.

The Fluke 101 is about as close as any meter gets to "safe" in untrained hands.
161 does have better fuses than 61E+. But I understand that nothing is 100% safe. I'm just saying I don't want it blowing up in my hands from that voltage.
I'm not a fan of carrying multiple multimeters, I guess ill just save up for BRYMEN BM789.
Anyone know of good place to get one in US or selling theirs?
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 23, 2022, 08:41:19 am
161 does have better fuses than 61E+.

The fuses only come into play when the cable is in the amps socket. Hopefully you'd never be poking at the 240V machines with the cable in that position so the difference in fuses is moot.

(nb. Joe doesn't do any tests on amps ranges)

For most "safety" situations the missing surge resistor is what counts, not the fuses, and that resistor is missing in both models.
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 23, 2022, 08:44:59 am
I'm not a fan of carrying multiple multimeters

Why would you carry both? You know where you're headed when you're away from the workbench, grab just the one you need.

PS: How will you measure low resistances or power consumption with only a single meter? Some measurements require two. There's also the matter of sanity checking: If you get a weird reading on your single meter then how will you double-check it.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on January 23, 2022, 12:01:41 pm
I wouldn't care much about 161e warranty for $50-60 price.
Got anything close to 161e feature wise, better protection around $100?
There is no free lunch. The Fluke 101 is the strict low end of Fluke with robustness but zero features (and quality control issues in my experience). Brymen/Greenlee is what you are going to find with reasonable robustness and more features at the same price range (also Klein). The newer Uni-T models seem to have reasonable mechanical robustness, but electrically they are not as good.

If not, would 161e be safe while working on 240v 3 phase machines? I would mod it to make it more robust but not electrical engineer, and I know it's not allowed to ask for help with that here sadly.
This is a question that can be approached from many angles.

From a multimeter perspective, the UT161E, the UT61E+ and many others (even the throwaways M830B-clones) will probably be just fine working on such systems during normal operation - they can withstand 240V just fine. However, if an unexpected event happens (high energy transients, for example) the chances of the cheaper equipment to survive are much smaller than a more robust one.

From the perspective of the operator and since you asked about "safety", Joe's tests cannot help you. Sure, a meter that survives a low energy transient has a higher probability of containing the damage of a high energy transient, but without testing it is a very far fetched claim. To verify this, a very high energy transient would have to be applied (something that the independent agencies claim to test to the full extent) and the meter would have to either (1) survive without damage or (2) die but in a controlled way to not harm the operator. In this particular scenario, I can tell for sure the M830B throwaways will be much less safe than anything else on the marketplace and will probably blow in your hands - an Uni-T meter would be less robust than a Fluke/Brymen/Klein, but without testing no one can really know.

The suggestion for more than one multimeter is very sound, but only if you are interested in investing twice your lowball budget. In this case, you can have the best of both worlds: the extra features of the Uni-T for the bench and the safety of a simpler robust model for the field.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 23, 2022, 04:37:28 pm
Quote
... an Uni-T meter would be less robust than a Fluke/Brymen/Klein, but without testing no one can really know.

From my spreadsheet,  I looked at a Klein MM2000 which was damaged with a 2kV transient .  I also looked at an MM500 which was damaged at 5kV (much shorter FWHH).    The MM500 was never exposed to any ESD transients.   

The second UNI-T UT139C I tested where I crept up on it also failed at 5kV with the 100us FWHH but it survived the ESD tests. 

From an electrical robustness standpoint,  I wouldn't place Klein in the same class as Fluke and Brymen.   Maybe Klein rebrands some better products that I have not looked at.  Still we have looked at Fluke and Brymen's low end products and the results speak for themselves. 

**
Which Klein product do you feel competes?  Maybe we can have a look at that.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on January 23, 2022, 07:09:15 pm
Quote
... an Uni-T meter would be less robust than a Fluke/Brymen/Klein, but without testing no one can really know.

From my spreadsheet,  I looked at a Klein MM2000 which was damaged with a 2kV transient .  I also looked at an MM500 which was damaged at 5kV (much shorter FWHH).    The MM500 was never exposed to any ESD transients.   

The second UNI-T UT139C I tested where I crept up on it also failed at 5kV with the 100us FWHH but it survived the ESD tests. 

From an electrical robustness standpoint,  I wouldn't place Klein in the same class as Fluke and Brymen.   Maybe Klein rebrands some better products that I have not looked at.  Still we have looked at Fluke and Brymen's low end products and the results speak for themselves. 

**
Which Klein product do you feel competes?  Maybe we can have a look at that.
Thanks for the highlights. I haven't heard good things about older Klein DMMs - the MM2000 is an older design, although the MM500 seems somewhat newer, albeit both are discontinued.

I heard good things about the newer line, especially the MM600 (averaging) and MM700 (TRMS) - obviously that, not having the same testset as yours nor the meters themselves, I can only speculate.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 24, 2022, 02:01:14 am
Quote
... I can only speculate.
   It funny how we see things so differently.   I look at the following ad and notice the same super cheap leads and thermocouple  I've found with so many low end meters our of China that I have sent to the recycle bin.   I think, this meter has no chance of surviving to the same levels as the Flukes or the Brymens I have looked at.  It would be lucky to survive ESE and maybe the low voltage transient generator.    As you said earlier,
Quote
... but without testing no one can really know.
 
 
https://www.amazon.com/Multimeter-Auto-Ranging-Klein-Tools-MM700/dp/B018CMKWSC/ref=sr_1_5?crid=1ZO9XQWDLIVVM&keywords=MM700&qid=1642989106&sprefix=mm700+%2Caps%2C102&sr=8-5 (https://www.amazon.com/Multimeter-Auto-Ranging-Klein-Tools-MM700/dp/B018CMKWSC/ref=sr_1_5?crid=1ZO9XQWDLIVVM&keywords=MM700&qid=1642989106&sprefix=mm700+%2Caps%2C102&sr=8-5)
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 24, 2022, 04:36:58 am
From an electrical robustness standpoint,  I wouldn't place Klein in the same class as Fluke and Brymen.

Maybe more interesting to look at something like these:

https://www.amprobe.com/product-category/multimeters/industrial-multimeters/ (https://www.amprobe.com/product-category/multimeters/industrial-multimeters/)

Looking at the claims... they ought to be the most robust meters out there.   ;)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 24, 2022, 12:01:09 pm
From an electrical robustness standpoint,  I wouldn't place Klein in the same class as Fluke and Brymen.

Maybe more interesting to look at something like these:

https://www.amprobe.com/product-category/multimeters/industrial-multimeters/ (https://www.amprobe.com/product-category/multimeters/industrial-multimeters/)

Looking at the claims... they ought to be the most robust meters out there.   ;)

They state:
Quote
AC Volts (45 Hz to 2 kHz) transient protection:    12 kV impulse (1.2 µS/50 µS) based on EN 61010-1:2001 impulse requirement for at CAT IV 1000 V product. This product should not be used in installations where transients exceed 12 kV.
   but I don't just test the ACV mode.    I used an Amprobe to set the cutoff of what I consider a robust meter.  You may remember I ran a higher end Amprobe and it did very poorly.   

If we wanted to find meters that were as robust as what I have seen with Fluke and Brymen,  I would look at Gossen and Hioki.  Both of these meters held up very well against my transient testing.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 24, 2022, 12:16:05 pm
They state:
Quote
AC Volts (45 Hz to 2 kHz) transient protection:    12 kV impulse (1.2 µS/50 µS) based on EN 61010-1:2001 impulse requirement for at CAT IV 1000 V product. This product should not be used in installations where transients exceed 12 kV.
   but I don't just test the ACV mode.    I used an Amprobe to set the cutoff of what I consider a robust meter.  You may remember I ran a higher end Amprobe and it did very poorly.   

Amprobe are big rebadgers. The meter you tested could be made by a completely different company than their "heavy duty" meters.

There's some pics with the back off here:

https://www.eevblog.com/forum/testgear/any-experience-with-an-amprobe-hd160c/msg170810/#msg170810 (https://www.eevblog.com/forum/testgear/any-experience-with-an-amprobe-hd160c/msg170810/#msg170810)

Check out the fuse:
(https://www.eevblog.com/forum/testgear/any-experience-with-an-amprobe-hd160c/?action=dlattach;attach=34509;image)

If we wanted to find meters that were as robust as what I have seen with Fluke and Brymen,  I would look at Gossen and Hioki.  Both of these meters held up very well against my transient testing.   

Sure, I'd like to see a Hioki DT4282 go under the hammer. Not only for robustness but to see how well it works ingeneral. :)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 24, 2022, 12:33:22 pm
The link you provided was from 2012 and
Quote
It's a wavetek original design ....
.   Wavetek hasn't been around for a long time.  I wonder how old this meter is.  Early 90s? 

I watched the video of the two guys dropping and and driving over it.   No transient tests....

Quote
Sure, I'd like to see a Hioki DT4282 go under the hammer. Not only for robustness but to see how well it works ingeneral. :)

Quote
That channel is getting close to 20k subscribers.  Like when it hit 2k, it seems like we should have a look at something special if it ever makes it up that high.   Last time we had a lot of fun with a high end Gossen.   

I listed it on the poll last time.  Not at all apposed to running it. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on January 24, 2022, 04:45:59 pm
Quote
... I can only speculate.
   It funny how we see things so differently.   I look at the following ad and notice the same super cheap leads and thermocouple  I've found with so many low end meters our of China that I have sent to the recycle bin.   I think, this meter has no chance of surviving to the same levels as the Flukes or the Brymens I have looked at.  It would be lucky to survive ESE and maybe the low voltage transient generator.    As you said earlier,
Quote
... but without testing no one can really know.
 
Indeed we see it differently. The thermocouple is visually similar to the Amprobe AM530 I had, the Agilent/Keysight U123x/U127x and a few others; the probes might be the cheaper models indeed, but the manufacturer sells replacements, so they are not necessarily a totally no-brand quality-uncontrolled product. The meter itself is quite well put together mechanically speaking (I had a MM700 once in my hands), and the manual (https://data.kleintools.com/sites/all/product_assets/documents/instructions/klein/MM700_1390112ART_WEB.pdf) is thorough enough with relevant specifications (RH%, Altitude, etc.) including drop test and independent verification.

Yes, we both agree that paper accepts anything and the extents of the agency testing can potentially leave lots of gaps but Klein is probably covering their asses on the "safety" part of it.

They state:
Quote
AC Volts (45 Hz to 2 kHz) transient protection:    12 kV impulse (1.2 µS/50 µS) based on EN 61010-1:2001 impulse requirement for at CAT IV 1000 V product. This product should not be used in installations where transients exceed 12 kV.
   but I don't just test the ACV mode.    I used an Amprobe to set the cutoff of what I consider a robust meter.  You may remember I ran a higher end Amprobe and it did very poorly.   
And here is where the difference between robustness and safety relies. The last sentence is covered by the EN61010 but does not mean the meter will survive.

If we wanted to find meters that were as robust as what I have seen with Fluke and Brymen,  I would look at Gossen and Hioki.  Both of these meters held up very well against my transient testing.   

Sure, I'd like to see a Hioki DT4282 go under the hammer. Not only for robustness but to see how well it works ingeneral. :)
Sanwa as well... The PC7000 (https://overseas.sanwa-meter.co.jp/products/digital_multimeters/index.html) is super nice and probably terribly expensive...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 24, 2022, 05:54:51 pm
The last sentence is covered by the EN61010 but does not mean the meter will survive.

We covered this a few times here.  I've gone so far as to site various sections from the standards and contacting a few of the manufactures.   As I have stated, I could not get a consensus.   If you know (know meaning with 100% certainly) what 61010 means, your are way ahead of me. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on January 24, 2022, 08:39:41 pm
The last sentence is covered by the EN61010 but does not mean the meter will survive.

We covered this a few times here.  I've gone so far as to site various sections from the standards and contacting a few of the manufactures.   As I have stated, I could not get a consensus.   If you know (know meaning with 100% certainly) what 61010 means, your are way ahead of me.
Indeed we both agree that it is wide open for interpretation - if it was the most stringent requirement (i.e., the meter survives) we would probably know by now. As I also said before, this perhaps is deliberate to cater to lower cost manufacturers - after all, these standards are frequently decided and agreed on committees comprised of representatives of various manufacturers.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 25, 2022, 01:46:50 am
I've never had enough interest in the subject to contact the agencies.  Have you?   I doubt these agencies follow the EEVBLOG so I am not sure how we could know unless someone were to contact them.   Otherwise, it's just a rinse and repeat cycle.  We may even get a consensus on the forums of what we believe, but that's not data.   As I stated, I went so far as to contact the manufactures and read the standards.  I've provided feedback from both.   If you have done anything further, I would like to hear your findings.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 25, 2022, 08:39:17 am
I think the only requirement is "fail safely". If the meter was required to survive then it would say so in the standard.

This leaves the final decision in the hands of the manufacturers. If a manufacturer wants to build a reputation for "bomb proof" then they try to make their meters survive transients (and charge accordingly). If they don't want that reputation, then... whatever. :-//

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 25, 2022, 11:37:10 am
I think the only requirement is "fail safely". If the meter was required to survive then it would say so in the standard.

This leaves the final decision in the hands of the manufacturers. If a manufacturer wants to build a reputation for "bomb proof" then they try to make their meters survive transients (and charge accordingly). If they don't want that reputation, then... whatever. :-//
Exactly my point. Rinse and repeat is all. No data.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 30, 2022, 02:22:48 pm
To celebrate reaching 20k subscribers, the following list of handheld meters will be considered. 

Brand model, requested by, link to manual
 
Hioki DT4282, Fungus,  https://www.hioki.com/euro-en/products/testers/dmm-4/id_5803 (https://www.hioki.com/euro-en/products/testers/dmm-4/id_5803)
Sanwa PC7000,  rsjsouza,  https://overseas.sanwa-meter.co.jp/download/index.html (https://overseas.sanwa-meter.co.jp/download/index.html)
AEMC MTX  3293B, Bogdan Oliver,  https://www.aemc.com/userfiles/files/resources/usermanuals/Multimeters/MTX3292B-3293B_EN.pdf (https://www.aemc.com/userfiles/files/resources/usermanuals/Multimeters/MTX3292B-3293B_EN.pdf)
Gossen Metrawatt  Metrahit Prime M248A, joeqsmith  (was it ever improved as someone suggested or was that a bunch of BS?)
Brymen BM857S , Fungus, https://brymen.eu/wp-content/uploads/biall/102020/102020.KARTA_EN..2015-07-08.1.pdf (https://brymen.eu/wp-content/uploads/biall/102020/102020.KARTA_EN..2015-07-08.1.pdf)
Testo 760-3 , Remco Van Triest,
UNI-T UT61E+,  jspencerg,  New unit to attempt to repeat the transient tests without any modifications
Title: Re: Handheld meter robustness testing
Post by: GuidoK on January 30, 2022, 04:18:16 pm
To celebrate reaching 20k subscribers, the following list of handheld meters will be considered. 

Brand model, requested by, link to manual
 
AEMC MTX  3293B, Bogdan Oliver,  https://www.aemc.com/userfiles/files/resources/usermanuals/Multimeters/MTX3292B-3293B_EN.pdf (https://www.aemc.com/userfiles/files/resources/usermanuals/Multimeters/MTX3292B-3293B_EN.pdf)
That Metrix MTX3293B is also available under the Chauvin Arnoux brand, Chauvin Arnoux CA5293-bt
https://catalog.chauvin-arnoux.com/fr_en/c-a-5293.html (https://catalog.chauvin-arnoux.com/fr_en/c-a-5293.html)
But it's the same meter (available with and without bluetooth)

I'd love to see that meter get tested as it's not a very common brand outside France and it's terratories.
High count expensive premium logging/graphing multimeter. Will it be as buggy as the Gossen metrawatt ultra, or as easy to kill with the grill starter as the UT181a, or as slow with displaying logging graphs as the Fluke 289?  ;D
Or is it that one hidden gem as the bm869s turned out to be?  ;) :)

That sanwa pc7000 looks feature and specwise very much like the BM896s (save the dual temp measurement), however significantly more expensive.
It's usb interface is also very similar. I think with the Ts Digital Multi Meter Viewer software (free generic dmm view software) (http://www.ts-software-jp.net/products/tsdmmview.html), there even was a remark about this in an older version using this setting, so I wonder if Sanwa makes this meter themselves or if it's partially a brymen? (or a joint venture or so?)

I love your video's/tests.
For me it's not just the electrical robustness testing, the quirks you find in the meters are the ones that I find most interesting. That is something other reviewers usually don't find. Maybe because they're sponsored, or maybe it requires that you have to spend real time with the meter going through everything and keep being alert. I think you have a real talent for that. :-+
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on January 30, 2022, 04:28:39 pm
1+ for Metrix MTX3293B... >:D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 30, 2022, 05:04:35 pm
I've added the Gossen just out of my own curiosity if they actually did do anything besides rename from Ultra to Prime. 
Title: Re: Handheld meter robustness testing
Post by: GuidoK on January 30, 2022, 05:44:43 pm
I've added the Gossen just out of my own curiosity if they actually did do anything besides rename from Ultra to Prime.
You're willing to buy another ~$1000 meter just to see if they added some shielding?  :wtf: ;D
That's some dedication  :-+

The software and the usb interface (if you dont have the BT version) are also ridiculously expensive. (although fluke software is also pretty expensive)
Title: Re: Handheld meter robustness testing
Post by: mqsaharan on January 30, 2022, 06:58:53 pm
To celebrate reaching 20k subscribers, the following list of handheld meters will be considered. 

Brand model, requested by, link to manual
 
Hioki DT4282, Fungus,  https://www.hioki.com/euro-en/products/testers/dmm-4/id_5803 (https://www.hioki.com/euro-en/products/testers/dmm-4/id_5803)
Sanwa PC7000,  rsjsouza,  https://overseas.sanwa-meter.co.jp/download/index.html (https://overseas.sanwa-meter.co.jp/download/index.html)
AEMC MTX  3293B, Bogdan Oliver,  https://www.aemc.com/userfiles/files/resources/usermanuals/Multimeters/MTX3292B-3293B_EN.pdf (https://www.aemc.com/userfiles/files/resources/usermanuals/Multimeters/MTX3292B-3293B_EN.pdf)

I am sorry, I couldn't resist. And I am also sorry in advance if my post is going to be wrongly interpreted.

Hioki DT4282:
Its younger brother gave great performance in your tests. I doubt it will be any different. Some of its quirks have already mentioned by some members here.

Sanwa PC7000:
After looking at its teardown, I am sure it is manufactured by Brymen since it is using Brymen branded chips. Even though these are lower specs models, I doubt they'll behave badly. If they do, it will be a slap in Brymen's face. MJLorton did a review and a teardown of this meter.

AEMC MTX 3293B:
Weirdly shaped but a very nice battery powered, handheld form factor benchtop multimeter, very capable, has math functions that are not normally found on handheld meters.
If my memory is serving me right, Joe, it has event counting function that you were looking for, a few years back.
Other than that, even though it is the next iteration, B model, its specs are almost the same. In a glance, the only difference I could spot is that the number of measurement records has been increased to 30,000 measurements as well as the records can be better managed in different files.
If they haven't installed any shield inside this B model as well, you better buy that sheet metal you used to shield Gossen Ultra before ordering this meter.
Its only my guess that it is using the same Hycon front end as 121GW. Perhaps someone who owns this or the previous non B model can confirm it.
As per their manual:
Has much more detailed specs than most meters. The only rival here is Gossen.
IP67 rated.
Has math functions.
Has 200kHz ACV bandwidth.
Has comparatively low burden voltage for current measurement.
Can measure voltage and current simultaneously.
I know nothing about its PC software capabilities. Must be great.
Has ability to use J, Pt100/Pt1000 in addition to K type thermocouple.

Operating temperature range is 0 to 40 degree C.
Battery life specified for 6V 2400mAh batteries is approximately 80 hours.
Specifications are guaranteed only after 30 minutes warm up.
The recovery time for the PTC thermistor is quoted as 10 minutes.
Does not have conductance function.
Bar graph update rate is still 5 times/sec, same as the display.
Capacitance measurement is slow in 1mF and 10mF ranges. Also, in capacitance function, resolution drops down to 1000 counts??? Am I reading it right?
Temperature coefficient is worse in some functions than Fluke 189. I don't know if anybody has practically checked the Fluke claimed temperature coefficient of 189 or other meters.

In the end, its your money, man. My suggestion is to get some other more popular meter, test it to death, show others how to improve it (like you did with UT61E) and soon you'll be celebrating 50k subscribers. I thought you don't care how many subscribers you get.
Or how about UT60BT: Its cheap, 9999 count, has better build than Anang 9999 count meters, has bluetooth. And hopefully, will die with the first hit of the grill starter just to keep its reputation that it is made by Uni Trend. But it will be way less burden on your pocket.

For me it's not just the electrical robustness testing, the quirks you find in the meters are the ones that I find most interesting. That is something other reviewers usually don't find. Maybe because they're sponsored, or maybe it requires that you have to spend real time with the meter going through everything and keep being alert. I think you have a real talent for that.
Well said. Me too.
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 30, 2022, 07:31:00 pm
Hioki DT4282:
Its younger brother gave great performance in your tests. I doubt it will be any different.

It's not just about robustness, it's also about finding quirks and checking the performance at the edges.

Clarification: If I were to ever drop that much money on a meter then I'd like to know all that other stuff. I'd want it to be the best all-round meter possible, eg. does it handle the edge cases as well as a Fluke 289?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 30, 2022, 07:39:50 pm
I just want to say I appreciate the feedback. 

Quote
You're willing to buy another ~$1000 meter just to see if they added some shielding?  :wtf:
Indeed.  I'm surprised anyone would even question my insanity at this point!   I waited a few years for the 121GW to mature before reviewing it.   Seems we have givin Gossen more than enough time. 


I doubt I will ever use the channel to
Quote
.... show others how to improve it ....
.  As an adult it seems irresponsible, not to mention potential liability.  That is unless you are referring to my offering feedback to the manufactures to improve their products.  There's a big difference when it comes to working with a group of professionals to solve problems.       

Quote
I thought you don't care how many subscribers you get.
  I don't or I would do things much differently.  Maybe just create some actual content once in a while.  Still it seems fitting to celebrate that there are so many of you crazy people out there.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on January 30, 2022, 09:01:32 pm
I've never had enough interest in the subject to contact the agencies.  Have you?   I doubt these agencies follow the EEVBLOG so I am not sure how we could know unless someone were to contact them.   Otherwise, it's just a rinse and repeat cycle.  We may even get a consensus on the forums of what we believe, but that's not data.   As I stated, I went so far as to contact the manufactures and read the standards.  I've provided feedback from both.   If you have done anything further, I would like to hear your findings.
Unfortunately I don't. I might have access to contacts on the cert agencies again later this year but, since liability about information is a critical part of their business, they tend to keep information quite compartmentalized across testing groups and therefore might not share anything that pertains to other class of products.

Sanwa PC7000:
After looking at its teardown, I am sure it is manufactured by Brymen since it is using Brymen branded chips. Even though these are lower specs models, I doubt they'll behave badly. If they do, it will be a slap in Brymen's face. MJLorton did a review and a teardown of this meter.
Interesting; I wasn't aware of (or perhaps forgot about) the PC7000 teardown - indeed it uses a BTC device inside. The other one I knew was the PC700 (https://youtu.be/3srAQ0KifPA).
Title: Re: Handheld meter robustness testing
Post by: GuidoK on January 30, 2022, 10:14:14 pm

If they haven't installed any shield inside this B model as well, you better buy that sheet metal you used to shield Gossen Ultra before ordering this meter.

There is indeed a short teardown topic here on the forum:
https://www.eevblog.com/forum/testgear/metrix-mtx3293-quick-teardown/ (https://www.eevblog.com/forum/testgear/metrix-mtx3293-quick-teardown/)

No shielding looks like it in the non b model.
And as it has no rotary dial, a whole row of relays that might be messed about with a magnet...  ;D

That processing chip looks interesting though. BGA by the looks of it.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on January 31, 2022, 04:26:28 am
Some time ago a few others had asked about looking at Benning and Testo.  Dave also showed the company who makes the 121GW had came out with their new top of the line meter.   That may be another option as well.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on January 31, 2022, 09:43:41 pm
I should probably add the BM857S to the shortlist because that's the one I own.  :)

(Old-school Brymen goodness)

Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 01, 2022, 05:15:36 am
Some time ago a few others had asked about looking at Benning
I assume in that case you're thinking about the Benning M12, their top model?
https://www.benning.de/products-en/testing-measuring-and-safety-equipment/digital-multimeter/logging-multimeter-mm-12.html (https://www.benning.de/products-en/testing-measuring-and-safety-equipment/digital-multimeter/logging-multimeter-mm-12.html)
4k/40k count, bluetooth logging, ac+dc, dual display, dBm
That is a rebrand of the Appatech Appa 506B:
https://www.appatech.com/en/product-553883/APPA-500-SERIES-MULTIMETERS-APPA-506-APPA-506B.html (https://www.appatech.com/en/product-553883/APPA-500-SERIES-MULTIMETERS-APPA-506-APPA-506B.html)

Appatech also has the Appa 505, a 10k/100k count meter, also sold under the name ISO-TECH IDM505
I think this was a popular meter here on the forum due to a good pricepoint at some time.

Quote
and Testo.
Looking at their meters, I'm not really blown away by their specs. It looks like all their meters are more targetted towards electricians/industry than electronics.
Then again, if that is their target market, the electrical robustness must be good.
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 01, 2022, 05:16:34 am
I should probably add the BM857S to the shortlist because that's the one I own.  :)

But that would be boring. ;D
Before the tests start we already know it will be robust, there won't be any quirks, it'll be reliable and there will be no monumental screw ups in the design ;D
Title: Re: Handheld meter robustness testing
Post by: Fungus on February 01, 2022, 08:01:21 am
But that would be boring. ;D
Before the tests start we already know it will be robust, there won't be any quirks, it'll be reliable and there will be no monumental screw ups in the design ;D

OTOH: Millions of people will see that Brymen makes square, boxy, "industrial" meters, too.

eg. One of the reasons I chose the BM857 is because there's almost no function overloading on the dial. People go on and on about the Fluke87V's simple user interface but this is even better. In a way the 857/859 are Brymen's most direct competitors to the 87V.
Title: Re: Handheld meter robustness testing
Post by: EEVblog on February 01, 2022, 08:44:37 am
eg. One of the reasons I chose the BM857 is because there's almost no function overloading on the dial. People go on and on about the Fluke87V's simple user interface but this is even better. In a way the 857/859 are Brymen's most direct competitors to the 87V.

The 87 has never had a "simple" user interface. It has three different power up modes like centre zero bargraph mode etc.
Title: Re: Handheld meter robustness testing
Post by: Fungus on February 01, 2022, 09:10:50 am
eg. One of the reasons I chose the BM857 is because there's almost no function overloading on the dial. People go on and on about the Fluke87V's simple user interface but this is even better. In a way the 857/859 are Brymen's most direct competitors to the 87V.

The 87 has never had a "simple" user interface. It has three different power up modes like centre zero bargraph mode etc.

Doesn't stop people going on and on about it though.

(I'm guessing most of them don't know about that feature or if they do they never use it)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 01, 2022, 11:44:10 am
Some time ago a few others had asked about looking at Benning
I assume in that case you're thinking about the Benning M12, their top model?
....
I didn't record the model numbers and have not looked at what they offer.  More just a reminder.   

I was not impressed with Keysight's lack of communication and how poorly the product performed but we could have a look at one of their high end meters.   
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 01, 2022, 04:23:56 pm

I was not impressed with Keysight's lack of communication and how poorly the product performed but we could have a look at one of their high end meters.
That's also very interesing. Maybe more people here are contemplating whether or not to buy a high end keysight meter
That cheap keysight indeed did not perform well on multiple aspects: electric robustness wasn't very good, the indentation spring from the knob completely failed (which looks like something they just didn't test; why use a different plastic when you can just use a plastictype you know that works as millions of meters use that), and the contact pads/springs from the knob were very worn after the lifecycle test (that surprised me very much...apparently not all pcb contactpads and springs are equal...)
Testing the a higher end meter would reveal whether Keysigth can't make a robust meter or that they just skimp on the quality of the cheaper models.
And that is an interesting comparison to Fluke (I think that is keysights main target market): the cheaper lower end Flukes are just as robust and have the same quality as the higher priced high end Fluke models (the china made 17b+ still has the best rotary knob in your test I believe?)

Although a 'cheap fluke' is still relative of course...where I live the Fluke 115 is still more expensive than a Brymen BM869S with silicone test leads and soft case...
Title: Re: Handheld meter robustness testing
Post by: jspencerg on February 11, 2022, 06:54:59 pm
I would like to see a high end meter tested if it were a new release with some innovations/ improvements for the portable meter market.  However,  watching you torture and rebuild the UT61E&E+ was most entertaining and educational.  I'd like you to run the repaired E+ to failure(12Kv?), get a replacement to test.  Test the virgin E+ and remove the asterisks you've placed on the E+ results.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 12, 2022, 12:58:42 am
Added it.   Keep in mind that I have ran more UNI-T products than any other brand and they never perform well.
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 12, 2022, 12:46:57 pm
So I stumbled upon this video on youtube showing the Brymen BM869S to be somewhat more susceptible from interference when measuring high resistance compared to other meters. The same way (with the hand) as for instance the Gossen Metrawatt was susceptible in the mV range.
I also did this test and indeed my BM869S also has this characteristic in considerable larger amount than a fluke 115 and an Aneng an8009 I compared it with.

And analyzing your video from the BM789 I think the new BM7## series might also be susceptible to it.

It's not a big problem for me as I never really measure such high resistance (I didn't even have a resistor that high so had to put a few in series), but I am interested in where this quirk comes from and if it's possible to correct within reasonable means (maybe add some shielding over a component or so).
Is it maybe a bespoke ADC that brymen uses that is more susceptible?
I could not detect the BM869s for example using significantly less current when measuring this high resistance compared to the other meters.

I know Dave once mentioned it in a video that when measuring high resistance the electric field radiating of your body can be picked up by the wiring because the current flowing at such measurements is tiny, but the difference between the BM869S and a few other meters is there.

It might be an interesting idea for a short video?

This was the video I saw on youtube:
https://youtu.be/Ehy_uZygdFA
(I think it's heavily inspired on your Gossen Metrawatt video  ;D)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 12, 2022, 04:05:00 pm
I was expecting the video showing the problem with 50Hz line.   The one you linked doesn't surprise me at all.   I make a habit of staying away from the setup when measuring low voltages, low currents, high resistance, etc to avoid such problems.    I frequently show the meters reading 40M and will talk about the stability. 

I like the Fluke 189.  I think it has 3 digits and will move 2 digits with a wave of my hand.

Recently there was a person posting about measuring a carbon resistor and how much it was drifting.   I made an attempt to replicate their tests and showed the effects of my walking into the lab, and then using a decent resistor.
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 12, 2022, 05:17:49 pm
Recently there was a person posting about measuring a carbon resistor and how much it was drifting.   I made an attempt to replicate their tests and showed the effects of my walking into the lab, and then using a decent resistor.

I understand that, but in this case it's not the resistor but the meter itself.
The difference in susceptibility between the BM869S and a lot of other meters is at least an order of a magnitude if I were to guess, maybe even 2 in extreme case depending on what control meter is used.
That is of course not as much as that quirk in the Gossen metrawatt (there it was at least 3 orders of mangitude in the extreme case I think), but still the difference is there.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 12, 2022, 05:50:09 pm
For fun, I repeated their test using the BM869s that I used for life cycle testing.  This meter has the later firmware which I expect would be closer to the OPs).     I also used one of my Fluke 189.   Both meters on the bench, sitting on a grounded ESD mat.     I tried with and without leads.  Leads were 27" long.   I left them untwisted laying across the mat.  I used that Caddock USVD2 2ppm 20.0007Meg resistor that is mounted in the foam as my reference.  This part has the banana connectors and will plug directly into meters that use the standard spacing.   Meter were set to record their min/max.  I then waved my hands around the meters and also got up from the chair a few times (maybe 2 feet away from the meters).  Keep in mind that we are in the middle of winter and the house is dry which it great for ESD.

 
With the leads:
Fluke 189  Max: 23.256M, Min: 7.772M
Brymen BM869s Max: 22.275M, Min: 17.800M

Without the leads (resistor plugged directly into the meters):
Fluke 189  Max: 20.032M, Min: 19.682M
Brymen BM869s Max: 20.134M, Min: 19.899M

Are both of these meters junk?  Maybe but I rather like them.   I suspect that the Fluke they show has a much higher voltage with their resistor attached than their Brymen.  For the people wanting to look at LEDs with their $400 meters, the 87V may be a better choice. 

***
Added picture of the test resistor used.  Also, I want to be VERY clear.  The test I ran is not controlled and I am NOT suggesting that the Fluke 189 is more susceptible than my Brymen BM869s! 

***
Because I opened the question of the test voltage, using the same 20M resistor, I measured the voltage across it with my old electrometer.  Obviously, at 20M we need the high input impedance.   I tried my 87V that I purchased brand new a couple years ago specifically for testing.  It's seen some abuse but I doubt it would have any effect on this measurement.

Fluke 87V:  3.590V
Brymen BM869s: 0.735V
UNI-T UT61E+: 0.814V
UNI-T UT181A: 0.809V

Of the four meters, it would make sense that the Fluke 87V would have better immunity in this particular case but  again, this is not how I would use the meter and I'm not a fan of these high test voltages (for electronics work).  But, if I needed to light some LEDs, this would be the ticket.
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 12, 2022, 06:59:19 pm
  I suspect that the Fluke they show has a much higher voltage with their resistor attached than their Brymen. 

Maybe, I don't have an 87V, but I doubt that that is the cause/explanation of this effect, at least not what I'm seeing with my meters. (that klein meter in the video is also not affected)

Like I said, I've measured the current. Of course this current is very very low (under 0.10µA), so the numbers I measure are not very accurate in an absolute way, but it does show their relative value to eachother (and had both the BM869s and an8009 in series to see if there are large differences in the µA range).
My fluke (115) uses about as much current as the BM869s and is noticeably less susceptible (also with min/max), and my an8009 is probably least susceptible (it has no min/max function, but looking at the display the difference is quite big so I'm pretty confident in that), and with my current measurement it uses slightly less current than the BM869s (the difference is not big, but it's there; maybe it has a slightly different internal resistance).
They're imho certainly not large differences that could explain the difference in susceptibility due to using considerably higher voltage for the resistance measurement.
But maybe I'm measuring incorrectly. I don't have an electrometer. I would think that the current measurement is also ok and that Ohms law also works with these high resistances.

I don't get the big min/max differences you get (I can only measure with leads) but where I live it's probably less cold and less dry.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 12, 2022, 08:19:22 pm
Check my last updated post for the voltage measurements.   The 87V would have the highest current at 3.59V/20M = 179.5nA.     

No doubt that there are other factors that would play into it.  I would expect meters with heavy filters would be less sensitive.   I don't record that data but we certainly have looked at it.  It seems I had ran a test once with the 121GW where I was modulating the resistance mode to get a feel of how their filters behave.  Heavy filter may mean slower response.  Fast response, like the original UT61E may mean more sensitive to ESD.   In the end, it's all a tradeoff.  That Gossen for example has the highest performance of any handheld meter I have looked at in some areas.   

I wouldn't be surprised if the companies didn't pick different filters (for example) based on the expected use.  The 87V may have been targeted for the industrial technicians where the 189 may have been more for the engineering group.  I certainly have no problem with the 189.     

It's up to the buyer to pick the tools for their particular use.  There's lots of options and the free meters from HF have the longest battery life I have measured and, they are FREE.  lol.  It's also about as good as my first Fluke.   

I am not surprised you wouldn't see the same results with your min/max test.  Again, it's not a controlled test.   

If your goal is to improve the BM869s, it would be best to open a discussion with Brymen.
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 12, 2022, 10:40:17 pm
It's up to the buyer to pick the tools for their particular use. 

.....


If your goal is to improve the BM869s, it would be best to open a discussion with Brymen.
No my goal is not to improve the bm869s. Like I said I never work with these high values. I work more in the mV ranges and bought the meter specifically for the 500k mode in the DC mV range combined with the high accuracy and the possibility to have it calibrated according to iso17025.
My post was more to bring it under the attention that the bm869s is more susceptible to this that a lot of other meters.

It's indeed up to the buyer to pick the tools for their use. But this kind of behaviour of course isn't advertized or specified, so if that's important to a buyer the only way to find out about it before purchase is if people write about it/document it. So maybe that was my goal :)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 13, 2022, 12:32:40 am
It's up to the buyer to pick the tools for their particular use. 

.....

If your goal is to improve the BM869s, it would be best to open a discussion with Brymen.
No my goal is not to improve the bm869s. ...   So maybe that was my goal :)

Your first comment. 
Quote
...but I am interested in where this quirk comes from and if it's possible to correct within reasonable means
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 13, 2022, 02:06:25 am
I ment that in a hypothetical way.
The process and means of whats involved to potentially correct it and what causes it interests me.

I never really measure high resistances so I have no need for it. (And I'm not going to modify anything inside my meter from a safety standpoint)

But I might contact Brymen :-+
See if they are aware of this behaviour and know how it causes the meter to behave like this :)

Edit:I might have misread your post about improving the bm869s; I thought you ment the bm869s I have here on my bench, so my bm869s (I'm not gonna modify that one), but you probably ment the bm869s in general, so the design of it. Then yes, why not ;D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on February 13, 2022, 05:06:20 am
Yes, I meant in general. 
Title: Re: Handheld meter robustness testing
Post by: Kosmic on February 14, 2022, 01:35:53 am
I used that Caddock USVD2 2ppm 20.0007Meg resistor that is mounted in the foam as my reference.

Small detail, but 2ppm is the TC of the ratio between the 2 resistors in the divider. Absolute TC is 10ppm/C.
Title: Re: Handheld meter robustness testing
Post by: cybercorfu on February 17, 2022, 06:01:17 pm
Found the problem it was a ceramic 20uF capacitor not completely broken just with 40kΩ  resistance causing semi short to ground
Title: Re: Handheld meter robustness testing
Post by: GuidoK on February 23, 2022, 07:27:52 am
To celebrate reaching 20k subscribers, the following list of handheld meters will be considered. 


I think this meter might also be interesting to test:
AmazonCommercial 90DM610
https://www.amazon.com/AmazonCommercial-Count-Digital-Multimeter-CATIV/dp/B07W1BL3RH (https://www.amazon.com/AmazonCommercial-Count-Digital-Multimeter-CATIV/dp/B07W1BL3RH)

This falls I think in the popular Brymen BM235 / Fluke 117/keysight u1230 class, so the "quality entry level" class I guess.
It's a rebranded CEM-9562
https://www.cem-instruments.com/en/Product/detail/id/1434 (https://www.cem-instruments.com/en/Product/detail/id/1434)
Independently tested and it has quite an elaborate input protection network (5 MOV's, 4 PTC's I believe). IP67 too (I don't know if that's a plus though)
But it's crazy cheap, $40 (in europe it's more expensive, €60), so even well under the price of the BM235 (I think about half that?).
I wonder if its as robust as it looks. I think it would also be interesting to put the rotary switch through the lifecycle testing. See if it's either fluke like quality or if it's keysight quality  ;D
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 04, 2022, 04:32:52 pm
That last video kicked the channel over the 20k mark..  Crazy!!   So as promised,  I plan to start the poll in a week or so.  In the mean time if you want to see some other meter ran that is not on the current list, feel free to chime in.

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg3976493/#msg3976493 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg3976493/#msg3976493)

https://www.youtube.com/watch?v=sfC39XGtEg4 (https://www.youtube.com/watch?v=sfC39XGtEg4)
Title: Re: Handheld meter robustness testing
Post by: theHWcave on May 06, 2022, 09:05:21 pm
Hi Joe, congrats in reaching 20K subs. Awesome and well deserved.

Please add the low budget KAIWEETS KM601 Smart meter. They sent me one and I did a review (it has a few problems). Inside, I thought its fuses are better than most budget meters but the rest of the protection is hardly worth mentioning. Then again the similar underwhelming AN8008 was doing quit well if I recall in your tests.  Anyway, checking with KAIWEETS regarding their CAT ratings, they stated their meters are tested by an independent Chinese testing lab, called NTEK. That lab's website shows an impressive list of international certificates. I know you are not checking CAT testing but I would be really interested in how well it stands up to your transient tests.
The KM601 is a smart meter and from the comments I got I think it is quit popular with beginners because it looks like a phone = familiar instead of of "complicated" like a multimeter, and of course it automatically switches between measuring volts, resistance and continuity, arguably the most common uses.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 07, 2022, 02:22:52 pm
Poll is now open. 

Please add the low budget KAIWEETS KM601 Smart meter.

Added.   

Title: Re: Handheld meter robustness testing
Post by: tautech on May 07, 2022, 07:48:19 pm
Poll is now open. 
:-//
Seems locked here.
Title: Re: Handheld meter robustness testing
Post by: Muttley Snickers on May 07, 2022, 10:18:56 pm
Poll is now open. 
:-//
Seems locked here.
It worked fine for me.   :-+
I voted for the Keysight which was probably a bad idea on my part. If it happens to fail miserably then the U1282A I have new in the box will become worthless value wise.   :-BROKE
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 07, 2022, 11:56:41 pm
It's too bad that Keysight's first meter did so poorly and they never responded to any of my emails.   If enough people vote for it, I'll give them another chance.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on May 08, 2022, 02:32:52 am
Despite I would like to see how the Keysight would fare, I voted for the Sanwa as it is a brand that never crossed paths with the zapperman  ;D
Title: Re: Handheld meter robustness testing
Post by: Fungus on May 08, 2022, 07:52:33 pm
I voted for the BM857s, not because I think it will fail but because I own one and I think Brymen's "industrial" range need more love.

PS: Don't forget to do the piece of string mod (https://www.eevblog.com/forum/testgear/help-me-decide-fluke-87v-or-brymen-bm789/msg3505584/#msg3505584) if you own one.  :)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 09, 2022, 12:40:46 am
Looks like the Benning fan club lost all their members. 
Title: Re: Handheld meter robustness testing
Post by: nightfire on May 09, 2022, 08:57:24 am
To be honest, here in germany Benning is famous for its Duspol brand (voltage testers)and in newer time for their application/device testers, not the multimeters...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 10, 2022, 12:34:21 pm
It's possible the people requesting I look at Benning were sales and marketing.  They may have only had a short presence on this forum.   Oddly enough is how many people have commented about running the top of the line HIOKI but it's lagging.
Title: Re: Handheld meter robustness testing
Post by: armandine2 on May 10, 2022, 06:02:38 pm
It's possible the people requesting I look at .....

Want fireworks or reputation
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 10, 2022, 10:49:19 pm
That's up to the viewers to decide.  I have no idea how the Benning would hold up having never looked at one. 
Title: Re: Handheld meter robustness testing
Post by: Muttley Snickers on May 13, 2022, 02:01:33 am
The multimeter poll is currently neck and neck, and way more exciting than our federal election.   :-DMM ::)

When will it end?  ???  and what happens if there is a draw?   :-\ 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 13, 2022, 02:42:12 am
We need a larger sample size.   
Title: Re: Handheld meter robustness testing
Post by: tautech on May 13, 2022, 03:46:34 am
The multimeter poll is currently neck and neck, and way more exciting than our federal election.   :-DMM ::)

When will it end?  ???  and what happens if there is a draw?   :-\
TBH I want Joe to fry the KS and have them tell him as he is not a professional they will not support one of the products they have sold him.  :-DD
And voted such.  >:D  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: PushUp on May 14, 2022, 09:00:18 am
...to make it a bit more exciting, I have a proposal:

I bought three "Gossen Metrawatt PM XTRA" via my local ebay from the same source. Normally you have to pay between 819,51 Euro and 915,11 Euro for one PMXTRA here in germany.



(https://i.postimg.cc/3r91R1G3/Bildschirmfoto-vom-2022-05-14-10-51-52.png) (https://postimg.cc/K4kBpnQW)



The PMXTRA is DAkkS calibrated from 2021-08 till 2023-02 with documents and it is new and nearly unused apart from some test measurements.

I would sell it for 400 Euro and take over the shipping which could be worth 20 - 30 Euro from Germany to the US, when 20000 participants give you 0,02 Euro each via PayPal or something like that.

However, in order to reduce shipping weight, I would keep the box and the test leads, thus you only get the PMXTRA within its green Holster and the papers. I would declare it as a "gift" to get rid of tax & Co.

The PMXTRA works fine, but when you use the backlight, there is a spot visible (between the "n" and the "F". My guess is, that it is a part of a foil, but I don't know, but would like to know:



(https://i.postimg.cc/rFmd9CPy/Bildschirmfoto-vom-2022-05-14-10-38-14.png) (https://postimages.org/)



As you intend to destroy it anyway (this version does not have relays), you could desolder the display to solve the mystery...thus I would be fine with my "bad" investment! ;-)

It is up to you or your 20000 followers - it is the one on the left:



(https://i.postimg.cc/bvB8pkRg/IMG-0215.jpg) (https://postimg.cc/1gwbKg2V)



Cheers!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 14, 2022, 04:05:26 pm
Thanks for the offer.  I'm really only interested on if GSM had added a shield to the Prime or if it is still the same as my Ultra. 
Title: Re: Handheld meter robustness testing
Post by: PushUp on May 15, 2022, 08:27:42 am
You are old enough to know the answer...  ^-^

When even ProbeMaster is not willing to put a plastic cap onto the end of their test leads, which Brymen does now with their 11 Euro silicon version since their latest batch, there is only one conclusion: When brands always and forever have copied ideas from others, they have no problem to be more flexible in changing/improving their products more often, whereas those inventing things on their own from scratch do have probably more principles and are more arrogant thus they do not care:

As far as Gossen Metrawatt GmbH is concerned, which is a member of GMC INSTRUMENTS-Group, there are even more hurdles to take, to get heared, because they will argue that you can buy any DMM for any purpose and that the PM PRIME BT is not the right one, when you need to use a strong magnet in front of the DMM...  :-DD

...but I will tell you in roughly 3 years time, when the guarantee of my PM PRIME (no BT) is over...  :-DMM


Cheers!  ;)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 15, 2022, 02:34:22 pm
Someone had wrote me about how GMW had told them that they had added the shielding.  I don't know the answer and why I offered to have another look. 

GMW offers a magnetic hanger for the Prime.   I'm in the process of designing a magnetic hanger that is nonmagnetic.  Cutting edge stuff.   Right there with the wireless ESD wrist strap. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 28, 2022, 02:24:23 am
Someone finally voted for Benning.   :-+

Looks like the KS is starting to pull away.  Shame on me for adding it to the poll at the last minute.   :-DD   You KS fan boys do know I'm not going to open the box and talk about how great the product is without turning it on so you can feel good about your purchases.  Keysight, if you're out there, hope you have your shit together.   

13 week lead time.  I'll start hunting around for stock. 

***
Also, I want to thank everyone who took the time to vote.   
Title: Re: Handheld meter robustness testing
Post by: mqsaharan on May 28, 2022, 04:04:38 am
You KS fan boys do know I'm not going to open the box and talk about how great the product is without turning it on so you can feel good about your purchases.  Keysight, if you're out there, hope you have your shit together.
That is the idea here.

Patiently waiting for your review of KS (if KS will be the final pick). Keeping in mind the slow response of GTDs and no MOVs in the circuit, my guess is it will not perform well with the transient testing, something like U1231A you tested. I may be wrong and the circuit may have better protection built into it. Only your practical tests will tell.
Would you kindly compare its functionality with 121GW (that is common among both) as both these meters are using the same DMM front end chip HY3131.
And thank you Joe for your efforts. Not many people including myself have tools and knowledge to check their equipment's limitations.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on May 28, 2022, 07:38:42 am
Someone finally voted for Benning.   :-+

Looks like the KS is starting to pull away.  Shame on me for adding it to the poll at the last minute.   :-DD   You KS fan boys do know I'm not going to open the box and talk about how great the product is without turning it on so you can feel good about your purchases.  Keysight, if you're out there, hope you have your shit together.   

13 week lead time.  I'll start hunting around for stock. 

***
Also, I want to thank everyone who took the time to vote.

Maybe we just want to see the Keysight pushed until it gives up the magic smoke and turns crispy...   :popcorn:
Title: Re: Handheld meter robustness testing
Post by: Fungus on May 28, 2022, 01:08:57 pm
Looks like the KS is starting to pull away.

Sock puppets.  :P
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 28, 2022, 03:46:50 pm
... Patiently waiting for your review of KS (if KS will be the final pick).

Assuming I can get my hands on one, I will be running the KS.  Maybe the higher end model.  Depends on what's available.

Keeping in mind the slow response of GTDs and no MOVs in the circuit, my guess is it will not perform well with the transient testing, something like U1231A you tested. I may be wrong and the circuit may have better protection built into it. Only your practical tests will tell.

I had looked at the 1282A's front end 7 years ago.

https://www.youtube.com/watch?v=wYCGnYglRjY (https://www.youtube.com/watch?v=wYCGnYglRjY)

Suggesting that GDTs are not as good as MOV for this application is based on ignorance.  If KS has their shit together (designer's did their job and were unhindered by marketing and sales), there is no reason for this meter to fail.  While the low end one I looked at had glass filled plastic that cracked in a couple thousand switch cycles and was damaged a levels the cheap Amprobe AM510 and Fluke 101 would survive,  I would hope that KS's high end meter will do well.   After all, they shouldn't be cutting costs at this price point.  Still, who puts ridged plastic into a spring design and doesn't test it.  No excuse for this. 

Of course I have looked at other meters that used a combination of GDTs, PTCs and high speed clamps to protect the meter without a MOV.   Both the Hioki DT4252 and Gossen Metrawatt Ultra M248B.  While the Hioki meter did eventually break down, none of the electronics were damaged.   The GMW was never damaged. 

https://www.youtube.com/watch?v=a2NVLzWV3_Q (https://www.youtube.com/watch?v=a2NVLzWV3_Q)

https://www.youtube.com/watch?v=XvpGa8ieit0 (https://www.youtube.com/watch?v=XvpGa8ieit0)

Would you kindly compare its functionality with 121GW (that is common among both) as both these meters are using the same DMM front end chip HY3131.
And thank you Joe for your efforts. Not many people including myself have tools and knowledge to check their equipment's limitations.

The easiest way to compare functionality is read both manuals.   Obviously the 121GW has some trick circuits in it, but the product is not very robust and the firmware is not polished and that crazy switch and story that goes with it isn't something you can make up.   Both meters are now fairly old and have been reviewed in detail.  Let me know if there is something specific you would like to see that has not been covered.

When I damaged the prototype 121GW, I asked Dave about using the damaged KS meter for parts.   I was surprised after his video on the KS that he would agree to use that same IC in a meter he was going to endorse.    If the KS is damaged, I have a 121GW that I may be able to use as a parts unit to revive it. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 28, 2022, 03:57:33 pm
Looks like the KS is starting to pull away.

Sock puppets.  :P
Much like any other voting.  Very few will take the time to vote.  Many will bitch about how the vote turned out.   An infinite amount of resources is then spent trying to change the the outcome.   
Title: Re: Handheld meter robustness testing
Post by: mqsaharan on May 29, 2022, 10:02:15 am
Hi Joe,
You are right, I made a stupid mistake suggesting that GDTs are not as good as MOVs. I am sorry. Of course you've looked at the meters without MOVs that performed well, I just forgot while writing that message. Thank you for setting me straight and for the video suggestions.
Regarding the request for meter comparison, again I forgot you usually compare a bunch of meters while checking their functionality. I don't have anything particular in mind to test.
Seems like I have forgotten quite a few things. I need to refresh my memory and knowledge.
Qasim.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on May 29, 2022, 05:47:15 pm
Hi Joe,
You are right, I made a stupid mistake suggesting that GDTs are not as good as MOVs. I am sorry. Of course you've looked at the meters without MOVs that performed well, I just forgot while writing that message. Thank you for setting me straight and for the video suggestions.
Regarding the request for meter comparison, again I forgot you usually compare a bunch of meters while checking their functionality. I don't have anything particular in mind to test.
Seems like I have forgotten quite a few things. I need to refresh my memory and knowledge.
Qasim.

What you wrote wasn't stupid and there was no need to be sorry.  I just wanted to make you aware of the work that had been done.   

I think the word "ignorance" has taken on a new meaning beyond how it's currently defined.   People take offense to it.    From Merriam-Webster:  lack of knowledge, education, or awareness.  I personally am ignorant about pretty much any subject you can come up with, including electronics and how to test meters.  Sadly, while I have dedicated much of my life to improving that, the older I get the more ignorant I become, or at least the more I am aware of my ignorance!   

Where "stupid" is defined as
a : slow of mind : obtuse
b : given to unintelligent decisions or acts : acting in an unintelligent or careless manner
c : lacking intelligence or reason : brutish

Example:
Amazon has the U1282A in stock but I am not so stupid as to pay their asking price!   :-DD
Title: Re: Handheld meter robustness testing
Post by: PushUp on May 30, 2022, 02:49:39 pm
Interesting (or boring fits better), that Benning seems to switch from Appa to Brymen with its upcoming "High-End-Multimeter BENNING MM 7-2":-DD, which seems to be a further "Brymen 78X"? clone with a slightly different display arrangement, but same specs...same test leads...same type-k...

Why should you pay 325 Euro for this DMM, when any Brymen is that much cheaper? I don't get it, because I don't think, that they managed to improve the clonky rotary knob or the useless backlight-timer...but we will see at the end of 2022-07, when it should be available:



(https://i.postimg.cc/bNWhY2Tn/Bildschirmfoto-vom-2022-05-30-16-37-32.png) (https://postimg.cc/mtYq8kKZ)


...at the moment only on the german website - not yet in EN...

https://www.benning.de/produkte/pruef-und-messtechnik/digital-multimeter/high-end-multimeter-mm-7-2.html (https://www.benning.de/produkte/pruef-und-messtechnik/digital-multimeter/high-end-multimeter-mm-7-2.html)


PDF-Manual in EN:

https://www.benning.de/produkte/pruef-und-messtechnik/digital-multimeter/high-end-multimeter-mm-7-2.html?sbd=GBR&file=files/benning/global_content/downloads/instruction_manuals/benning_mm_7_2_instruction_manual_en.pdf&cid=134224 (https://www.benning.de/produkte/pruef-und-messtechnik/digital-multimeter/high-end-multimeter-mm-7-2.html?sbd=GBR&file=files/benning/global_content/downloads/instruction_manuals/benning_mm_7_2_instruction_manual_en.pdf&cid=134224)


Cheers!  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: EEVblog on June 01, 2022, 07:15:48 am
Interesting (or boring fits better), that Benning seems to switch from Appa to Brymen with its upcoming "High-End-Multimeter BENNING MM 7-2":-DD, which seems to be a further "Brymen 78X"? clone with a slightly different display arrangement, but same specs...same test leads...same type-k...

Interesting, didn't know there was this variant. The LCD is very different to the 78x series.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 01, 2022, 08:37:47 pm
The KeySight arrived.  I ended up with a UT1282A (higher end version).   Supply chains are a total crap shoot.   

As always, if there's any non-destructive tests you would like to see before I run it, just let me know.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on June 01, 2022, 09:53:32 pm
As always, if there's any non-destructive tests you would like to see before I run it, just let me know.

How about actual measured input impedance on all the AC and DC ranges?
Title: Re: Handheld meter robustness testing
Post by: floobydust on June 02, 2022, 04:33:43 am
Suggesting that GDTs are not as good as MOV for this application is based on ignorance.  [...]
The ignorance is follow through current, which you do not include. Mains plus transients superimposed is a disaster with anything that crowbars such as GDT.
Fluke started with GDT and changed to MOV's, Brymen would have ditched the large MOV's long ago if they were practical.
Title: Re: Handheld meter robustness testing
Post by: nightfire on June 02, 2022, 10:20:30 am
Why should you pay 325 Euro for this DMM, when any Brymen is that much cheaper? I don't get it, because I don't think, that they managed to improve the clonky rotary knob or the useless backlight-timer...but we will see at the end of 2022-07, when it should be available:

There are several reasons to go for Benning, when you are in germany:
- Distribution channel: Maybe the standard distribution channel where you always buy your stuff at carries this DMM, and you do not have to go to Welectron for a brymen
- Brymen= Whats that? Never heard of- and Benning, reputable brand (Duspol etc.) on the german market, so lets go this route
- Service and calibration from a german company, so that the beloved papertrail can be produced
- User manual in german (Users of Benning branded products are mostly electricians, so english knowledge is not always perfect)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 02, 2022, 10:39:04 am
Suggesting that GDTs are not as good as MOV for this application is based on ignorance.  [...]
The ignorance is follow through current, which you do not include. Mains plus transients superimposed is a disaster with anything that crowbars such as GDT.
Fluke started with GDT and changed to MOV's, Brymen would have ditched the large MOV's long ago if they were practical.


"Application" is in context to this thread.   Not being aware of what this thread is about is ignorance.  While it's been covered many times over the last several years, suggesting my testing has anything to do with AC line testing or the safety standards is stupid.     

I understand you want to talk about disasters rather than robustness.  Failing to understand that the clamps (MOVs, GDTs) sit behind a large PTC and surge rated resistor, ignorance.    Every now and then people do comment about clamping the line.   Consider that the PTC and resistor will be over 2k ohms when cold.  My light bulbs present more of a load.    Of course the load my bulbs present are fairly constant when compared with a PTC.   Consider also that some of the meter's circuits will conduct far below where the GDTs or MOVs will come into play.
Title: Re: Handheld meter robustness testing
Post by: Fungus on June 02, 2022, 10:51:17 am
MOVs are boring. GDTs are pretty, you can see them doing their thing.   :-+
Title: Re: Handheld meter robustness testing
Post by: bd139 on June 02, 2022, 12:27:52 pm
You do realise you’re not supposed to use them as indicators?  >:D

Reminds me of that BM22s I was using to check HV with. It got backlit. Still works fine!
Title: Re: Handheld meter robustness testing
Post by: Fungus on June 02, 2022, 12:30:31 pm
That's got me thinking. I've never made a GDT clock...

How much voltage will I need to make the display nice and visible?
Title: Re: Handheld meter robustness testing
Post by: bd139 on June 02, 2022, 01:01:37 pm
I'd buy a GDT clock.

May have to turn it off when I want to use the WiFi though  :-DD
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on June 02, 2022, 01:58:41 pm
I'd buy a GDT clock.

May have to turn it off when I want to use the WiFi though  :-DD

Yeah you could call it a radio clock...
Title: Re: Handheld meter robustness testing
Post by: floobydust on June 02, 2022, 06:24:26 pm
I have only one GDT with a clear glass case, all others are ceramic with no glow joy. It's a 90V (neon) part and a bit flat for a clock.
Tried a NE-2 but it exploded.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 05, 2022, 06:22:26 pm
I have some free time and plan to start looking at the Keysight U1282A.   There have been several reviews for this meter already, including my own where we take a look at the front end design.   If there is something specifically you would like to see, now is the time to ask.  The last Keysight meter I damaged was not repairable and I don't have a lot of confidence in this meter going into it. 

https://www.youtube.com/watch?v=7NGoXnQLgkw (https://www.youtube.com/watch?v=7NGoXnQLgkw)

https://www.youtube.com/watch?v=kajevAH8fqg (https://www.youtube.com/watch?v=kajevAH8fqg)

https://www.youtube.com/watch?v=wYCGnYglRjY (https://www.youtube.com/watch?v=wYCGnYglRjY)
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 05, 2022, 06:28:51 pm
 :popcorn:
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 06, 2022, 02:21:37 am
Thanks for linking my video, despite being in Kling... *ahem* portuguese; I don't even remember what I said and tested on it, but I recall I didn't open it (it was still in warranty).

I look forward for your review and tests. It still ticks valiantly on my bench despite some mishaps in medium voltage.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2022, 03:01:16 am
Thanks for linking my video, despite being in Kling... *ahem* portuguese; I don't even remember what I said and tested on it, but I recall I didn't open it (it was still in warranty).

I look forward for your review and tests. It still ticks valiantly on my bench despite some mishaps in medium voltage.

I plan to work on small segments to allow people enough time to provide feedback.  I ran into a couple of snags right from the start.   When you select the ACV function, then select frequency, how do you get it back to the standard mode?  The only way I saw was to change the function and return back to ACV.   

The other problem I see is I can't get the frequency counter to work.  Like the UNI-T meter, I wonder if they over spec'ed it.   Does yours work?

***
corrected
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 06, 2022, 11:43:59 am
Thanks for linking my video, despite being in Kling... *ahem* portuguese; I don't even remember what I said and tested on it, but I recall I didn't open it (it was still in warranty).

I look forward for your review and tests. It still ticks valiantly on my bench despite some mishaps in medium voltage.


I plan to work on small segments to allow people to provide feedback.  I ran into a couple of snags right from the start.   When you select the ACV function, then select frequency, how do you get it back to the standard mode?  The only way I saw was to change the function and return back to ACV.
   

One of the most confusing aspects of the U1282A is its button interface. When you go to the Frequency, you can long press the "Dual" button and get back to AC. However, if you go to either period or duty cycle by pressing the same "Hz" button, you can't go back to V unless you press the "Hz" button to get to the frequency and then long press the "Dual". I end up flipping the rotary switch.

The other problem I see is I can get the frequency counter to work.  Like the UNI-T meter, I wonder if they over spec'ed it.   Does yours work?

You can or can't? The frequency works alright, but there is a derating curve of sorts that is more aggressive on the VAC Hz function when compared to the MHz range. I recall I can get several hundreds of kHz out of it. The MHz range goes to many MHz IIRC (it is specified (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf) to 10MHz)

I did a long feature overview (https://www.eevblog.com/forum/chat/keysight-handheld-meters-pros-and-cons/msg1792946/#msg1792946) of the U1282A and occasionally compared it to its sibling U1273A, which might be useful when you are exploring your meter. For convenience, it is copied below. 

I own a U1273A and a U1282A and had owned a U1233A. I haven't used the U1233A enough to have a strong opinion other than its size and packed features are a very nice feature. I tend to prefer the U1273A but the U1282A has its uses.

Leeching off bitseeker's excellent response, I have the following addenduns:
(I may be forgetting a few things)

U1273A:
- OLED display. The most controversial factor of this meter. Unbeatable indoors legibility and, if used in dark conditions, you will never be caught with a dark display (due to backlight timeout) while trying to evaluate the best places to put the probes. Its durability is unknown and various reports around this forum are concentrated on the previous model U1253 (only one or two concerned this model). Mine still works after 4~5 years of manufacturing (about 1-1/2 years of moderate use of about 1 hour per day). Threads here ([url]https://www.eevblog.com/forum/testgear/keysight-u1273a-heavily-discounted-at-fry_s/[/url]), here ([url]https://www.eevblog.com/forum/testgear/anyone-with-an-agilentkeysight-oled-dmm-still-happy-with-the-display-gt5-years/[/url]), here ([url]https://www.eevblog.com/forum/testgear/agilent-u1253b-display-becoming-unreadable/[/url]) and here ([url]https://www.eevblog.com/forum/testgear/agilent-u1253b-oled-slowly-going-bad/[/url]) (there may be others).
- Decent speed autorange.
- Frequency measurements do not require the signal to have zero crossing - good for signals with  DC offset. (common to U127x/U128x)
- Various hold mechanisms (common to U127x/U128x), including a trigger (like an oscilloscope) and Auto hold.
- Built-in data logging with different trigger modes - the one I use the most is the event trigger, which allows to log only when a stable input is detected. (common to U127x/U128x)
- Low impedance ACV/DCV mode for eliminating ghost voltages (LoZ). Since in the bench I use several boards and power supplies and host PCs interconnected, this mode is quite useful to detect wide ground variations in unknown conditions. Lowest voltage difference is 3VAC - here ([url]https://www.eevblog.com/forum/testgear/dmms-with-lowz-feature/msg1407849/#msg1407849[/url])
- Can compensate for DC offset voltages when measuring resistance (smart ohms). I personally have seen myself using this mode more than I initially believed during my repairs around the house on HVAC, heater and other permanent installations.
- Good capacitance meter with excellent range: up to 33mF. Slow on auto-range, especially on higher ranges (somewhat expected).
- 3V Diode checker that tests in both directions so you don't have to swap the leads.
- Beep can only be fully disabled or fully enabled. No sensible settings to disable the turn on beep.
- Continuity tester has a very interesting melody setting. A gimmick.
- Uses AAA batteries (common to U127x/U128x). Not a big fan due to the fear of leakage, but this meter sees quite a bit of action and the batteries usually are replaced every 6~8 months with my use.
- Very well built and a bit tall for my taste, but it has good rotary switch and terminal jacks. The various buttons with the number of aggregated functions not always make much sense - I sometimes see myself pressing a number of buttons until I get what I want or just need to go back to the previous display.
- I love its leads (Dave dislikes them due to length) as they have banana jacks on both sides. Easy to plug accessories.
- Earlier versions, like mine, were sensitive to high-frequency RF on the input jacks that could alter the displayed value.

U1282A:
- LCD Display. Excellent size and quite clear.
- Its biggest drawback to me is the slow autorange.
- Frequency measurements do not require the signal to have zero crossing - good for signals with  DC offset. (common to U127x/U128x)
- Various hold mechanisms (common to U127x/U128x), including a trigger (like an oscilloscope) and Auto hold. However, on this meter the switch between the different auto-hold modes only via a setup menu - the U127x cycles as you press the button. To me this detracts from the functionality.
- Built-in data logging with different trigger modes - the one I use the most is the event trigger, which allows to log only when a stable input is detected. (common to U127x/U128x). Other modes are manual and timed - quite useful as well.
- It has NCV with configurable sensitivity settings. Despite this, I find this NCV still too sensitive for reasonable use. I prefer to use my Fluke LVD2 that is a spot tester.
- Good capacitance meter with excellent range: up to 100mF. Slow on auto-range, especially on higher ranges (somewhat expected).
- It has square wave output with configurable duty cycle and frequency. Since the frequency is only switchable on the setup menu, it is somewhat cumbersome to use for my taste.
- It has an input for remote control to perform manual hold of measurements. Perhaps it has its uses for others, but I haven't seen the need to purchase its accessory.
- 3V Diode checker. Lacks the auto-diode feature of the U127x that I like.
- Beep can be disabled more sensibly than U127x - either disable the turn on beep (leaving continuity beep still on) or disable everything. 
- Uses AAA batteries (common to U127x/U128x). Not a big fan due to the fear of leakage, especially because one of its big advertisements is the very long battery endurance. Better check them constantly.
- Very well built and large meter that can easily act as a weapon. It has rubbery feel rotary switch (if that is an issue or not it is a highly personal matter). The various buttons with the number of aggregated functions not always make much sense - I sometimes see myself pressing a number of buttons until I get what I want or just need to go back to the previous display. IP67 rated, but mine only sees action on the lab.
- Decent leads but do not allow plugging accessories.
- Came with USB accessory for firmware updating and data logging. A big plus to me.
- Did not come with the temperature probe. A fail in my opinion.
- Not plagued by high-frequency RF problem of the early U127x modes.

Interesting clips about autorange comparison and the melody setting (shameless plug)
Melody continuity:
[url]https://www.youtube.com/watch?v=fH6rL2U2oAI[/url] ([url]https://www.youtube.com/watch?v=fH6rL2U2oAI[/url])

Autorange comparison:
[url]https://www.youtube.com/watch?v=EWZ0OSjYnvg[/url] ([url]https://www.youtube.com/watch?v=EWZ0OSjYnvg[/url])
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2022, 04:10:34 pm
One of the most confusing aspects of the U1282A is its button interface. When you go to the Frequency, you can long press the "Dual" button and get back to AC. However, if you go to either period or duty cycle by pressing the same "Hz" button, you can't go back to V unless you press the "Hz" button to get to the frequency and then long press the "Dual". I end up flipping the rotary switch.

 :palm:   Thank you very much.  The UI has a college student's final project vibe to it.  Not what I would expect from Keysight.

FYI, mine came without documentation.  While the contents paper states it comes with it, there is a paper that talks about them going green.  No problem.   I go to get the manuals and the first thing they want was my email address.  Google search found the direct links.   I'm fine with electronic copies but don't make me have to create an account to gain access to them.   


You can or can't? The frequency works alright, but there is a derating curve of sorts that is more aggressive on the VAC Hz function when compared to the MHz range. I recall I can get several hundreds of kHz out of it. The MHz range goes to many MHz IIRC (it is specified (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf) to 10MHz)

Unless I am not understanding the document you linked, they claim 100MHz. 

***
From your post:
Quote
- Frequency measurements do not require the signal to have zero crossing - good for signals with  DC offset. (common to U127x/U128x)

The meter I have appears to require the zero crossing.   You can't use it to look at digital signals for example.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2022, 04:26:52 pm
In this intro video, I go through a basic checkout which includes looking at the frequency function.   

https://www.youtube.com/watch?v=QFino110A0c (https://www.youtube.com/watch?v=QFino110A0c)
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 06, 2022, 04:29:09 pm
What is the 100 division factor? Is it a special setting or an external probe (Sorry I do not have time to check the manual now).
A fast check on my U1282A showed that it worked at 1MHz with 4Vpp, but not at 2MHz.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2022, 04:47:29 pm
What is the 100 division factor? Is it a special setting or an external probe (Sorry I do not have time to check the manual now).
A fast check on my U1282A showed that it worked at 1MHz with 4Vpp, but not at 2MHz.

You need to press the Range selection to get it to work above 2MHz.     
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 06, 2022, 06:07:01 pm
You need to press the Range selection to get it to work above 2MHz.   

That got me to 36MHz at 37MHz the readings where wrong (38.xxxMz).

The specifications saying <1MHz and <20Mhz for stated precision is obvious correct, but they do not say that the meter fails completely before maximum range value.

It is not that I will hold it against the meter, I will generally rate anything in the MHz range as outside a standard multimeter capabilities. A scope or a frequency counter with BNC connector (or better) and 50ohm input impedance is the tool for that.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2022, 06:34:15 pm
Not even half the rated frequency, which is what I am finding as well.   As I continued to increase the frequency, the meter will display more than 2X the actual.   Everything I tried ended with the same results.

The last meter I looked at was a UNI-T which advertised their counter over 200MHz.  I wouldn't expect Keysight to be on par with the UNI-T brand but here we are.     

HP > Agilent > Keysight > UNI-sigh 
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 06, 2022, 07:16:37 pm
Not even half the rated frequency, which is what I am finding as well.   As I continued to increase the frequency, the meter will display more than 2X the actual.   Everything I tried ended with the same results.

The last meter I looked at was a UNI-T which advertised their counter over 200MHz.  I wouldn't expect Keysight to be on par with the UNI-T brand but here we are.     

HP > Agilent > Keysight > UNI-sigh

Hence my use of the derogatory "Keyshite". I am, sad to say, not surprised in the least.
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 06, 2022, 07:39:21 pm
Not even half the rated frequency, which is what I am finding as well.   As I continued to increase the frequency, the meter will display more than 2X the actual.   Everything I tried ended with the same results.

The last meter I looked at was a UNI-T which advertised their counter over 200MHz.  I wouldn't expect Keysight to be on par with the UNI-T brand but here we are.     

HP > Agilent > Keysight > UNI-sigh


Hence my use of the derogatory "Keyshite". I am, sad to say, not surprised in the least.

Yeah, really bad meter, specifications says 20MHz and it can show up to 36MHz.

The meter is inside specifications. The way the specifications are stated makes it very easy to assume the meter can do more than specified and it can, but not as much as it looks like.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 06, 2022, 08:58:43 pm
I have no problem with the meter not being able to read up this high but the fact their marketing group would use such a tactic is a big disappointment.   

Back when I opened up the poll,  I considered adding a Siglent Arb to the mix.  We had bought one of their low end models to try out where I work.   The encoder on it is really bad.   I was going to offer to get one of their higher end models but  I'm glad now I didn't as everytime I use my equipment at home and rotate a working encoder, I am reminded how bad that Siglent is.   Would it have really cost them that much more to at least make the encoder work?   Along the same lines,  with Keysight Go Green, they could have save some ink not adding that 99.999 MHz to the document.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 06, 2022, 09:26:32 pm
In this intro video, I go through a basic checkout which includes looking at the frequency function.   

https://www.youtube.com/watch?v=QFino110A0c (https://www.youtube.com/watch?v=QFino110A0c)

Your wife's comment about the Uni-T and the annoying beeping when turning the knob definitely rang home to me. Why do they always insist on them beeping when pressing buttons or turning knobs, it's so annoying. Why can't they leave the beeping for things that matter like continuity checks, or errors??? I have a BM789 and was so excited to learn that I could turn off the beeper until I found that it also disabled it for continuity etc.  |O. O well, at least it's still better than my Ideal clamp meter... That dang thing lets out the loudest most annoying beep any time it senses over 40V  :palm:
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 06, 2022, 10:50:42 pm
Your wife's comment about the Uni-T and the annoying beeping when turning the knob definitely rang home to me. Why do they always insist on them beeping when pressing buttons or turning knobs, it's so annoying.

Yep.

It could be a really short "bip", too, that might be tolerable, but noooo... it has to be "beeeeeeeeeeeeeep". Every. Single. Time.   :palm:

We're only one video in and it's already confirmed what I suspected, ie. that Keysight meters are horrible. I could buy three top-of-the-range Brymens for the price of that meter and still have change left over for a nice dinner.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 02:20:31 am
I was going to use the UNI-T 181A as part of the review today.  Attempting to turn it, the meter was dead.  The meter was purchased brand new in March 2016 and is now only 6 years old.   

Placing the meter on the charger, it appeared to attempt to charge then faulted out with the power LED rapidly flashing.     I tried it a few more times and the meter when black.   :palm:

Pulling it apart, the battery was at 0.000 volts.  Not something you can just buy at the local drug store or gas station.   Attempting to manually charge it, I was able to get the meter to boot up and so I plugged it back into the charger.   Dead.  I manually turned on the meter where I was greeted with a message requesting the charger to be plugged in.  As it turns out, they use the 400mA fuse during charging and it had blown with the battery being flat.   

 I'll let it charge overnight.  I doubt that battery has much life in it.   I wish they had used standard batteries.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 07, 2022, 02:48:03 am
FYI, mine came without documentation.  While the contents paper states it comes with it, there is a paper that talks about them going green.  No problem.   I go to get the manuals and the first thing they want was my email address.  Google search found the direct links.   I'm fine with electronic copies but don't make me have to create an account to gain access to them.
The paper document that came with it was not very useful. Regarding the e-mail account, this is somewhat recent. Pretty stupid.


You can or can't? The frequency works alright, but there is a derating curve of sorts that is more aggressive on the VAC Hz function when compared to the MHz range. I recall I can get several hundreds of kHz out of it. The MHz range goes to many MHz IIRC (it is specified (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf) to 10MHz)

Unless I am not understanding the document you linked, they claim 100MHz. 
Interesting; there are two tables: one named Frequency specification for U1281A / U1282A at page 14 which states 9.9999MHz and another named Frequency counter specification for U1282A at page 16 which states up to 99.999MHz with a "divide-by-100" and up to 1.8VP spec. This last one works on the MHz range selection.


From your post:
Quote
- Frequency measurements do not require the signal to have zero crossing - good for signals with  DC offset. (common to U127x/U128x)

The meter I have appears to require the zero crossing.   You can't use it to look at digital signals for example.
Quite interesting your meter fails on this. Mine does not, in both VAC and MHz.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 07, 2022, 02:48:55 am
Your wife's comment about the Uni-T and the annoying beeping when turning the knob definitely rang home to me. Why do they always insist on them beeping when pressing buttons or turning knobs, it's so annoying.

Yep.

It could be a really short "bip", too, that might be tolerable, but noooo... it has to be "beeeeeeeeeeeeeep". Every. Single. Time.   :palm:

We're only one video in and it's already confirmed what I suspected, ie. that Keysight meters are horrible. I could buy three top-of-the-range Brymens for the price of that meter and still have change left over for a nice dinner.
This can be turned off via the setup menu, leaving only the button beeps (which are also annoying IMHO), the continuity buzzer and the Vsense.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 07, 2022, 02:51:22 am
I have a BM789 and was so excited to learn that I could turn off the beeper until I found that it also disabled it for continuity etc.  |O. O well, at least it's still better than my Ideal clamp meter... That dang thing lets out the loudest most annoying beep any time it senses over 40V  :palm:
The U127x is also like that - enable all or disable all.

One of the best features of the Flukes 87V, 179 and 189, the Brymen BM857 and the UT-61E1 is they are quite silent.  :=\

1 Not the 61; I don't know what I was thinking)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 04:46:41 am
Interesting; there are two tables: one named Frequency specification for U1281A / U1282A at page 14 which states 9.9999MHz and another named Frequency counter specification for U1282A at page 16 which states up to 99.999MHz with a "divide-by-100" and up to 1.8VP spec. This last one works on the MHz range selection.
The manual you linked is clear about which is the Frequency Counter.    I assume that divide statement is just showing that the resolution has changed, not that the meter requires some sort of external clock divider.  If they did require such a device, they make no reference to it in the accessories or show it's use in any of the manuals that I found.     I also can't imagine anyone spec'ing their 1Hz counter to 1THz with unknown accuracy, provided to attached the 1THz divider.   Maybe the bottom of the bowl companies. 

If you can, try to see how high your meter can actually read frequency using the frequency counter function.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 07, 2022, 05:25:23 am
One of the best features of the Flukes 87V, 179 and 189, the Brymen BM857 and the UT-61E is they are quite silent.  :=\

My BM789 is identical in beeps to my Fluke 189. Both are silent enough that I can live with them, but I still wish the buttons could be silenced independent of the wrong jack and continuity beepers.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 07, 2022, 07:28:39 am
Not even half the rated frequency, which is what I am finding as well.   As I continued to increase the frequency, the meter will display more than 2X the actual.   Everything I tried ended with the same results.

The last meter I looked at was a UNI-T which advertised their counter over 200MHz.  I wouldn't expect Keysight to be on par with the UNI-T brand but here we are.     

HP > Agilent > Keysight > UNI-sigh


Hence my use of the derogatory "Keyshite". I am, sad to say, not surprised in the least.

Yeah, really bad meter, specifications says 20MHz and it can show up to 36MHz.

The meter is inside specifications. The way the specifications are stated makes it very easy to assume the meter can do more than specified and it can, but not as much as it looks like.

So, you don't see it as a problem that they are resorting to marketing bs/misleading statements in the manual, instead of engineering excellence, as they would have in the past?
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 07, 2022, 07:43:46 am
So, you don't see it as a problem that they are resorting to marketing bs/misleading statements in the manual, instead of engineering excellence, as they would have in the past?

It do not make the meter bad, it may still be "engineering excellence".
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 07, 2022, 07:57:35 am
So, you don't see it as a problem that they are resorting to marketing bs/misleading statements in the manual, instead of engineering excellence, as they would have in the past?

It do not make the meter bad, it may still be "engineering excellence".

Yes, indeed. However the attitude of the corporation to how it does business, and how it treats its customers these days is what has prompted me to rename it so. If any other premium manufacturer behaved similarly, I'd criticise them too.

Improbable specification claims from the likes of Uni-T may be taken with a pinch of salt, but when Keysight, Fluke, Rohde & Schwarz etc etc state something, I expect it to be clear, and to be true.
Title: Re: Handheld meter robustness testing
Post by: bd139 on August 07, 2022, 08:38:59 am
I’m confused. Which misleading statement in the manual?

There are so many compounding problems with frequency measurement on DMMs that it’s difficult to recommend them as suitable after about 200KHz or so.

Just to note I have owned a keysight handheld. One of the lower end non OLED units from the last redesign series. The user interface was absolutely dire and some of the features such as touch hold were completely useless. And disappointingly one of the buttons was sticky out of the factory. If they’d spent a couple more months on it, it’d be a good meter. I wouldn’t buy another keysight handheld b
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 07, 2022, 10:00:53 am
I’m confused. Which misleading statement in the manual?

There are so many compounding problems with frequency measurement on DMMs that it’s difficult to recommend them as suitable after about 200KHz or so.

Just to note I have owned a keysight handheld. One of the lower end non OLED units from the last redesign series. The user interface was absolutely dire and some of the features such as touch hold were completely useless. And disappointingly one of the buttons was sticky out of the factory. If they’d spent a couple more months on it, it’d be a good meter. I wouldn’t buy another keysight handheld b

This:

You can or can't? The frequency works alright, but there is a derating curve of sorts that is more aggressive on the VAC Hz function when compared to the MHz range. I recall I can get several hundreds of kHz out of it. The MHz range goes to many MHz IIRC (it is specified (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf) to 10MHz)

Unless I am not understanding the document you linked, they claim 100MHz. 

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1559392)

That's snipped from the manual for the meter on the Keysight website.
Title: Re: Handheld meter robustness testing
Post by: bd139 on August 07, 2022, 10:12:37 am
Ah that tells me that the display range is 99MHz as they only specify it up to 20MHz. I don’t have a problem with that. If you’re getting 38Mhz out of it that’s fairly ok.

My heathkit counter is the same. It will display up to 99.999 MHz but only count to about 35Mhz.

Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 07, 2022, 10:25:47 am
Earlier in the manual it only specifies it up to 9.9999 MHz... confused yet?

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1559899)
Title: Re: Handheld meter robustness testing
Post by: bd139 on August 07, 2022, 11:08:15 am
In that case their technical authors should be shot. Or at least mildly beaten with a hose.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 07, 2022, 12:25:13 pm
Interesting; there are two tables: one named Frequency specification for U1281A / U1282A at page 14 which states 9.9999MHz and another named Frequency counter specification for U1282A at page 16 which states up to 99.999MHz with a "divide-by-100" and up to 1.8VP spec. This last one works on the MHz range selection.
The manual you linked is clear about which is the Frequency Counter.    I assume that divide statement is just showing that the resolution has changed, not that the meter requires some sort of external clock divider.  If they did require such a device, they make no reference to it in the accessories or show it's use in any of the manuals that I found.     I also can't imagine anyone spec'ing their 1Hz counter to 1THz with unknown accuracy, provided to attached the 1THz divider.   Maybe the bottom of the bowl companies. 
I wasn't sure which band you referred when mentioned the 100MHz, so I had to check and found the second table of the MHz range. My first message was clearly stating the first table that goes up to 9.9999MHz, which may correspond to the VAC range. Regarding the divider, it was just to highlight what the table meant, not implying you were doing something wrong by not using any external device/accessory - I too can infer they mean a reduction in resolution.

Before we move forward, I need to clarify that I am no fanboy of Keysight or any other brand, just like or dislike each product of any brand on its own merits. The videos on my channel will evidence this.

If you can, try to see how high your meter can actually read frequency using the frequency counter function.
I need to find where I put my RF generator, but I got a very accurate measurement using my 30MHz generator set to 1.0VPP on the MHz function.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 02:01:38 pm
It's no problem if you don't want to run it.  I wasn't accusing anyone of being a fanboy.  This was a brand new meter and I was just curious if Keysight's older revisions may have performed better.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 04:41:19 pm
A deeper look into the Keysight's frequency counter. 

https://www.youtube.com/watch?v=dAxCiMD0GJA (https://www.youtube.com/watch?v=dAxCiMD0GJA)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 07:43:08 pm
Maybe I am the only one who found the attached comment a bit odd.   It's a very old meter and has been reviewed before including by Dave.  Imagine if the purpose was for damage control.  :-DD    Seems we should address them... 


Dear Keysight, 
While I did make an attempt to contact you several years ago when I first became interested in looking at handheld meters, you refused to acknowledge me.   I am an independent reviewer and except in very rare cases, all of the products I have looked at were purchased out of pocket at my own expense.   My only interest is in how electrically robust these meters are when ran against a common set of tests.   A standard transient generator is used and there is very little human involvement.  In other words, there is no bias.    You can be assured that your product will be treated with the same care as any others I have looked at.   It will be ranked on how well it performs.   

PS, I hope you learned your lesson about using glass filled plastics for your function switch.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 07, 2022, 08:11:19 pm
Earlier in the manual it only specifies it up to 9.9999 MHz... confused yet?

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1559899)


This isn't the only misleading wording. They did the same thing with accuracy and temperature coefficient. In one section they imply that the stated accuracy specifications are accurate over the whole range, but then later they list the temp coefficient when outside of 18-28C.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 08:25:40 pm
One just describes the drift, which could be well within the accuracy.  Say for example, we wanted to compensate for that error to tighten the measurement.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 07, 2022, 10:26:51 pm
Maybe I am the only one who found the attached comment a bit odd.   It's a very old meter and has been reviewed before including by Dave.

Very strange...
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 07, 2022, 10:46:13 pm
It's no problem if you don't want to run it.  I wasn't accusing anyone of being a fanboy.  This was a brand new meter and I was just curious if Keysight's older revisions may have performed better.
Cool; I just wanted to be sure. :-+

I will watch your two videos and let you know of any discrepancies - after all, any manufacturer has the "right to change the product without prior or express warning". :-/

(Been caught on that a few times).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 10:57:30 pm
Maybe I am the only one who found the attached comment a bit odd.   It's a very old meter and has been reviewed before including by Dave.

Very strange...

I just checked out his channel and don't believe I have ever watched any of his videos.   Skimming the last one, no sign of the Keysight meter yet.  It will be interesting to see what he comes up with.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 07, 2022, 11:27:11 pm
It's no problem if you don't want to run it.  I wasn't accusing anyone of being a fanboy.  This was a brand new meter and I was just curious if Keysight's older revisions may have performed better.
Cool; I just wanted to be sure. :-+

I will watch your two videos and let you know of any discrepancies - after all, any manufacturer has the "right to change the product without prior or express warning". :-/

(Been caught on that a few times).

It's just very odd how it behaves.   It's very repeatable and appears independent of the amplitude (within reason) and wave shape.  I tried both a sine as well as a squareish wave, using both LVDS and PECL drivers.   I've also tried various terminations, none of which seems to matter.   Not all of that made it on the video as I didn't see it adding anything.  Had it made any difference in how the meter responded, I would have left it in.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 08, 2022, 12:49:07 am
One just describes the drift, which could be well within the accuracy.  Say for example, we wanted to compensate for that error to tighten the measurement.

I always thought that the temperature coefficient was additional error that needed to be added to the published specification when outside of the specified (usually 18-28C) range. Is my interpretation wrong?
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 08, 2022, 01:02:56 am
One just describes the drift, which could be well within the accuracy.  Say for example, we wanted to compensate for that error to tighten the measurement.

I always thought that the temperature coefficient was additional error that needed to be added to the published specification when outside of the specified (usually 18-28C) range. Is my interpretation wrong?

Also from the next page in the datasheet they specifically state the accuracy is 23C +-5C. It might be my interpretation, but to say "Full accuracy from -20C to 55C" then later state "Accuracy is given as ± (% of reading + counts of least significant digit) at 23 °C ± 5 °C" seems like questionable wording to me.

Quotes from https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 09, 2022, 12:35:03 am
Let me start by stating I would always turn to the manufacture to explain any questions I have about a specifications.   It's not my design and I was not involved with writing the documentation.  That said, I finally downloaded the documentation for the meter and would interpret it as ... 

"Full accuracy from -20C to 55C" is just a general statement suggesting they have characterized it over this range.   

Unless otherwise specified,  "Accuracy is given as ± (% of reading + counts of least significant digit) at 23 °C ± 5 °C"  provides the default accuracy.   
You will find notes for example, the temp coefficient for the 6V range is 0.075 x .......  in cases where the defaults do not apply. 

If you wanted to operate outside of the specified 23 °C ± 5 °C range,  you need to account for it using the temperature coefficient "0.05 x (specified accuracy) / °C (from –20 °C to 18 °C or 28 °C to 55 °C)"

Again, always ask the manufacture.   

Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 09, 2022, 12:49:24 am
It's no problem if you don't want to run it.  I wasn't accusing anyone of being a fanboy.  This was a brand new meter and I was just curious if Keysight's older revisions may have performed better.
Cool; I just wanted to be sure. :-+

I will watch your two videos and let you know of any discrepancies - after all, any manufacturer has the "right to change the product without prior or express warning". :-/

(Been caught on that a few times).

It's just very odd how it behaves.   It's very repeatable and appears independent of the amplitude (within reason) and wave shape.  I tried both a sine as well as a squareish wave, using both LVDS and PECL drivers.   I've also tried various terminations, none of which seems to matter.   Not all of that made it on the video as I didn't see it adding anything.  Had it made any difference in how the meter responded, I would have left it in.   
I got to run it on the signal generator; up to -30dBm I got about 19MHz; at at -20dBm I got 25MHz, -10dBm I got about 27MHz and at 0dBm I got 31MHz.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 09, 2022, 01:38:15 am
Thank you for running this test.  Your data is exactly what I had measured:

Input signal, U1282A measured
29MHz, 29MHz
30MHz, 30MHz
31MHz, 77.5MHz
32, 80
33, 82.5
34, 85
35, 87.5

based on your 32, 80 I expect your meter would behave much the same at the other data points.   I think the meter displays zero once I took it above this.  Sorry, I didn't write it down where it actually stopped doing anything.   

Sad to see CEM of all companies actually putting something similar in their spec and surpassing it while Keysight.....   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 09, 2022, 01:59:12 am
Let me start by stating I would always turn to the manufacture to explain any questions I have about a specifications. 

Absolutely. Always get clarification with the manufacturer if there are questions about a specification.

I only brought up this wording because it is different than the wording on most other DMM spec sheets and COULD be misinterpreted to imply that the stated specifications were accurate across the entire operating range (vs the actual 18-28C range). Pointing out another instance (similar to the frequency limits) that can be misread to interpret the specifications to be something different than the actual printed specification.
Title: Re: Handheld meter robustness testing
Post by: bd139 on August 09, 2022, 08:09:29 am
Hope you have a registered VAT number then  :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 09, 2022, 12:28:02 pm
Hope you have a registered VAT number then  :-DD

From my early attempts to contact them, I knew there would be no support if I bought one.   I never tried to contact them about the poor quality of their detent spring as I just didn't see the point or wasting any more time with it.   

To be fair, they are present on this site and I expect are aware of what I have presented.  They have never attempted to contact me.   Still, I find it odd they would send the same meter to another reviewer now that I have started to look at it.   I doubt that was by accident.    :-DD 
Title: Re: Handheld meter robustness testing
Post by: bd139 on August 09, 2022, 12:33:35 pm
Did Keysight ever send you any kit?

If not I suspect they're scared you'll break it :-DD

Incidentally I had a Keysight U1241C. Could have been a decent meter but they screwed up touch hold, the UI sucked and the buttons were sticky  :palm:. I did a YT video ages ago about it against a Fluke 87V which ended up with me punching the KS meter off the desk...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 09, 2022, 02:14:24 pm
Did Keysight ever send you any kit?

They never even took the time to acknowledge my emails.   So, no.   The only meters that were supplied "free of charge" from the manufactures were
Dave's preproduction 121GWs (the second I purchased) along with Brymen's prototype and production meters (except for my first BM869s which I purchased).   While I have had a few places on these low end stores offereing to send me products to review, I decline them.   UNI-T contacted me that one time but again, once I explained what I was doing that ended the discussion. 

Brymen has been the only company who has expressed any interest in seeing how their products stack up on a level playing field. 
Title: Re: Handheld meter robustness testing
Post by: Neutrion on August 09, 2022, 07:22:43 pm
If the meter is not destroyed yet, than here is my wish list:
-The controversal dc biased AC mV overload test, which you were also doing earlier on some meters.(Not on video but were posting the results here in the forum.)
-Display update speed when measuring changing current. (You did a comparison once on different meters.)
-General current reading capability, to test its freq limit, its response to different waveforms, especially square waves which could come from a VFD, also with low duty cycles.
-Crest mode, also with current (If that would not be part of the standard procedure.)

Edit:
-Continuity current, and range, also how it keeps the false alarms at bay (or not.) This might be tested on a real circuit.

Thanks in advance!
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 09, 2022, 11:23:40 pm
(...)
-Crest mode, also with current (If that would not be part of the standard procedure.)

Edit:
-Continuity current, and range, also how it keeps the false alarms at bay (or not.) This might be tested on a real circuit.

Thanks in advance!
I did some tests of crest response and autorange speed of various meters on my channel, including the U1282A. The video is in portuguese, though.

Crest
https://youtu.be/ZDGdnGpG3ho

Autorange
https://youtu.be/EWZ0OSjYnvg

Regarding false alarms, the U1282A is very strident with its Vsense and the input jack alert, which is more a scream whenever you switch to any current range. This is a reason why I don't use it in current ranges - it is excessively annoying and I can't think of a single reason why someone would think this was a good idea.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 12:40:03 am
If the meter is not destroyed yet, than here is my wish list:
-The controversal dc biased AC mV overload test, which you were also doing earlier on some meters.(Not on video but were posting the results here in the forum.)
-Display update speed when measuring changing current. (You did a comparison once on different meters.)
-General current reading capability, to test its freq limit, its response to different waveforms, especially square waves which could come from a VFD, also with low duty cycles.
-Crest mode, also with current (If that would not be part of the standard procedure.)

Edit:
-Continuity current, and range, also how it keeps the false alarms at bay (or not.) This might be tested on a real circuit.

Thanks in advance!
For those not aware, background for this may be found here:
https://www.eevblog.com/forum/testgear/brymen-bm789/ (https://www.eevblog.com/forum/testgear/brymen-bm789/)

There's some pretty funny posts in the thread.   One year later, I still see it as a pointless case outside of a bit of entertainment it may provide.   Like I mentioned back then I will use a blocking cap and that hasn't changed.   

So while I am sure I can find cases where the Keysight has problems, that's nothing I would hold against the meter. 

Rarely I do anything with the current inputs on these meters.  Any idea what video shows the test you are interested in?   If so, provide a link and I will see about replicating it.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 12:44:06 am
Regarding false alarms, the U1282A is very strident with its Vsense and the input jack alert, which is more a scream whenever you switch to any current range. This is a reason why I don't use it in current ranges - it is excessively annoying and I can't think of a single reason why someone would think this was a good idea.

To try and warn the beginner that once they move that lead, that meter presents basically a short and whey they go to try and measure their home outlets current by placing the meters lead directly into the outputs, they are in for a surprise.    :-DD   

That alarm they have was a surprise...  Kids seem to like these reaction videos.  Had I recorded that moment, you would have seen the look of WTF????!!!   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 10, 2022, 01:02:16 am
To try and warn the beginner that once they move that lead, that meter presents basically a short and whey they go to try and measure their home outlets current by placing the meters lead directly into the outputs, they are in for a surprise.    :-DD   

I walked by a new EE's desk at work today, and I saw a meter apart and a fuse out... Apparently the Fluke 117 must not have that alarm.  :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 04:18:03 am
I installed the software for the meter.  I have to say, the software UNI-T and CEM has provided would be much better for my needs and that should say it all.   

I change the sample rate to 10 seconds, stop and restart, it still runs a 1sps.   I try to change where it logs data but it doesn't seem to allow it.  Zoom into an area, sorry, you can't really.    Stats, what are stats.   Looks like you can export the data to Excel but say the system dies.  You now have this XML file.  Where's the import function and post processing?     It seems to have a lot of features to stay in touch with me while I am out playing a round of golf or getting my foo foo drink.    I don't golf and drink black coffee and so these features are useless in that respect.   Looks more like one of the marketing employee's kids wrote it than a group of professionals.       

On the plus side, they did at least document the commands so putting something together wouldn't take a lot of effort.   

Someone asked about running some day long tests.  I plan to let it run and see if the software is at least stable and that I can get the data into a useful format. 

If you use their software, what's been your experience?   Think its the best data capture software ever created?   Crash and burn on you a lot?   

***
I see the import data. 
Tried the export to CSV.  Still would need a way to do something with the data.
Don't press report unless you want to restart the app as it seems to hang it.
The only way I have found to clear the plot was to exit the software and restart it. 

Good stuff...
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 10, 2022, 07:29:54 am
I installed the software for the meter.  I have to say, the software UNI-T and CEM has provided would be much better for my needs and that should say it all.   

With this meter you can use TestController: https://lygte-info.dk/project/TestControllerIntro%20UK.html (https://lygte-info.dk/project/TestControllerIntro%20UK.html)
It have a lot more flexibility, including handle more than one meter or other devices at a time. TestController will run on Windows, Linux and Mac.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 12:45:59 pm
From the YT comments, moved here for ease..

Quote
joe smith
8 hours ago
I have the software installed and I guess working.   What are the requirements for what you are attempting to measure?  Saying resistance of a cryo coil doesn't tell me much.   What is the value you are expecting to read, what sort of accuracy, how much drift do you expect from the test coil?    Have you looked at the specs for the meter and you know it it is capable of making the measurement you need?   It's easy to waste a bunch of time taking useless data.  I would like to make sure I understand what you are looking for and then we can perhaps use a low tempco resistor in that same range to check it.    Obviously, you know it's not a 4-wire Kelvin bench device and it wouldn't compare to even my old bench meters.

Chuan Liu
2 hours ago
 @joe smith  My colleague is expecting the copper coil resistance to drop from 8 ohm to around 1 ohm within several minutes, and maintain that level for several hours. The accuracy of this meter's 60 Ohm range is 0.15 % + 20, which is not impressive, but it is acceptable for the purpose at the current stage. I would like to find out if the meter can maintain its accuracy and linearity within a prolonged period. If the meter can maintain a good linearity, I think the data would still be usable, even with a lower accuracy. We are expecting to receive some microohm meters with proper 4-wire leads sometime in the future. Maybe we can use it to adjust the offset afterward, providing the Keysight meter can maintain a good linearity. Another way is to use a current source to inject a constant current through the coil and sue the meter to measure the voltage drop, but the accuracy of the current source will have an impact on the result, which we need to do some math with. Therefore I'd like to find out the meter's accuracy and linearity on both DCV range and resistance range. We do have some bench meters, but they are quite old and we don't have any suitable hardware to setup the PC connection.

I'm surprised you would consider using a 2-wire approach below 10.  I have a very old HP34401A that I bought new when they first came out.  It's like a wind up childs toy compared with the HP3489A (shown with a 1ohm standard attached).   When using the this meter, I will do some software tricks to improve the measurement.   Just make sure you understand what you are after before you collect any data.  I would expect what you are asking to be a paper study more than anything.   
 
Shown after 7 hours with a 40R0000 0.005% +/-1ppm S102K attached.   Meter just setting on  my desk in open air (no temp control).   After 3 hours, something happens that we see a spike down to 1.239 ohms.  There is nothing going on during this time.  Office is closed off.   So I am going to suggest the software/firmware/hardware has a problem.      Zooming into this area, and ignoring the glitch we can see the meter changes 2 counts.   I have a low tempco 0.5ohm I'll attach and let it run for the day.   
Title: Re: Handheld meter robustness testing
Post by: Neutrion on August 10, 2022, 02:00:00 pm
If the meter is not destroyed yet, than here is my wish list:
-The controversal dc biased AC mV overload test, which you were also doing earlier on some meters.(Not on video but were posting the results here in the forum.)
-Display update speed when measuring changing current. (You did a comparison once on different meters.)
-General current reading capability, to test its freq limit, its response to different waveforms, especially square waves which could come from a VFD, also with low duty cycles.
-Crest mode, also with current (If that would not be part of the standard procedure.)

Edit:
-Continuity current, and range, also how it keeps the false alarms at bay (or not.) This might be tested on a real circuit.

Thanks in advance!
For those not aware, background for this may be found here:
https://www.eevblog.com/forum/testgear/brymen-bm789/ (https://www.eevblog.com/forum/testgear/brymen-bm789/)

There's some pretty funny posts in the thread.   One year later, I still see it as a pointless case outside of a bit of entertainment it may provide.   Like I mentioned back then I will use a blocking cap and that hasn't changed.   

So while I am sure I can find cases where the Keysight has problems, that's nothing I would hold against the meter. 

Rarely I do anything with the current inputs on these meters.  Any idea what video shows the test you are interested in?   If so, provide a link and I will see about replicating it.
I am only interested whether the overload would be indicated or not.
The topic with many meters tested for this is actualy this one:
https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/ (https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/)

Maybe one or two meter passed this test from all of yours.

Here is the crest mode test. Would be avesome to have this test with current as well. Not many have current probes to have an idea about the meters limits.
https://www.youtube.com/watch?v=K-4L2JarVxA (https://www.youtube.com/watch?v=K-4L2JarVxA)

Unfortunately I could not find the current display update rate "test" as it was just a small part of another video.
You were having the meters in series and changing the test current. Some meters were responding really
Slowly.
I only found this so far, for current reading test:
https://www.youtube.com/watch?v=89HDlSq8WEg (https://www.youtube.com/watch?v=89HDlSq8WEg)

The AC current freq. Is also interesting because Keysight claims it to read up to 100Khz. With similar accuracy like the Brymen BM869. The BM789 is specced only up to 3 kHz but maybe reads even higher I don't remember anyone ever checked this.

Edit:
Now that you made your wife to be the standard switch-feeling tester, it is a pity that you didn't show her the dt830 meter. Maybe it turns out that I am not alone. :)
Now she is going to get a lot of invitations from all the meter manufacturers from all over the world.


Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 10, 2022, 02:59:32 pm
I installed the software for the meter.  I have to say, the software UNI-T and CEM has provided would be much better for my needs and that should say it all.   

I change the sample rate to 10 seconds, stop and restart, it still runs a 1sps.   I try to change where it logs data but it doesn't seem to allow it.  Zoom into an area, sorry, you can't really.    Stats, what are stats.   Looks like you can export the data to Excel but say the system dies.  You now have this XML file.  Where's the import function and post processing?     It seems to have a lot of features to stay in touch with me while I am out playing a round of golf or getting my foo foo drink.    I don't golf and drink black coffee and so these features are useless in that respect.   Looks more like one of the marketing employee's kids wrote it than a group of professionals.       

On the plus side, they did at least document the commands so putting something together wouldn't take a lot of effort.   

Someone asked about running some day long tests.  I plan to let it run and see if the software is at least stable and that I can get the data into a useful format. 

If you use their software, what's been your experience?   Think its the best data capture software ever created?   Crash and burn on you a lot?   

***
I see the import data. 
Tried the export to CSV.  Still would need a way to do something with the data.
Don't press report unless you want to restart the app as it seems to hang it.
The only way I have found to clear the plot was to exit the software and restart it. 

Good stuff...
The SW generally works well for me (although I am on Windows 8 and not the newfangled 10), but the biggest annoyance is that is requires MS Office installed for any reporting/export functions. That is a PITA as I haven't installed MS Office in years in my PCs (I use some really excellent clones such as the Softmaker Freeoffice).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 03:23:28 pm
For those not aware, background for this may be found here:
https://www.eevblog.com/forum/testgear/brymen-bm789/ (https://www.eevblog.com/forum/testgear/brymen-bm789/)

There's some pretty funny posts in the thread.   One year later, I still see it as a pointless case outside of a bit of entertainment it may provide.   Like I mentioned back then I will use a blocking cap and that hasn't changed.   

So while I am sure I can find cases where the Keysight has problems, that's nothing I would hold against the meter. 

Rarely I do anything with the current inputs on these meters.  Any idea what video shows the test you are interested in?   If so, provide a link and I will see about replicating it.
I am only interested whether the overload would be indicated or not.
The topic with many meters tested for this is actualy this one:
https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/ (https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/)

Maybe one or two meter passed this test from all of yours.

I'm not aware of any meters I have that are perfect.  If you feel there were, let me know which and I can have another look.   It is very possible that someone has a specific case they were running and I had meters that would handle it but let's be clear that doesn't suggest they wouldn't have other problems.   As shown in the photo, you could see that Keysight is no exception.   

Quote
You were having the meters in series and changing the test current. Some meters were responding really Slowly.
You may have noticed from watching reviews for this Keysight that it is very slow.    I think the Martin (??) guy had made a video showing how it compared.  I think Dave may have made one as well.   You may want to try searching YT and see what's out there.  It's an old meter and many people have looked at it. 

Quote
Now that you made your wife to be the standard switch-feeling tester, it is a pity that you didn't show her the dt830 meter.
I didn't want to waste too much of her time but thought it was interesting that the Fluke 87V and UNI-T shown were both subjected to the 50,000 cycle life test and still have a better feel than the Keysight.   I never would have guessed she would like the BM869s.  Many people complain about how tight the switch is and the small knob.   
Title: Re: Handheld meter robustness testing
Post by: Neutrion on August 10, 2022, 03:23:55 pm
(...)
-Crest mode, also with current (If that would not be part of the standard procedure.)

Edit:
-Continuity current, and range, also how it keeps the false alarms at bay (or not.) This might be tested on a real circuit.

Thanks in advance!
I did some tests of crest response and autorange speed of various meters on my channel, including the U1282A. The video is in portuguese, though.

Crest
https://youtu.be/ZDGdnGpG3ho

Autorange
https://youtu.be/EWZ0OSjYnvg

Regarding false alarms, the U1282A is very strident with its Vsense and the input jack alert, which is more a scream whenever you switch to any current range. This is a reason why I don't use it in current ranges - it is excessively annoying and I can't think of a single reason why someone would think this was a good idea.
Hi! The 1282 Is specified in Crest mode with repetitive signals down to 250 microseconds, so it should go further down than in your test.
It is also interesting that a single pulse is also specified but only with 1ms. This single pulse behaviour in peak detect mod is also a not very much tested thing, however in peak detect mode it would be quiet important to know about it.

With false alarms I meant the short beep in continuity mode when it encounters some capacity. With small test currents it is not trivial to get rid of it.
Title: Re: Handheld meter robustness testing
Post by: Neutrion on August 10, 2022, 03:32:49 pm

I'm not aware of any meters I have that are perfect.  If you feel there were, let me know which and I can have another look.   It is very possible that someone has a specific case they were running and I had meters that would handle it but let's be clear that doesn't suggest they wouldn't have other problems.   As shown in the photo, you could see that Keysight is no exception.   
I did not state that any meter was perfect, it was only about this specific test. Maybe the extech was the only one with ac+dc mV scale which passed it.

Quote
You were having the meters in series and changing the test current. Some meters were responding really Slowly.
You may have noticed from watching reviews for this Keysight that it is very slow.    I think the Martin (??) guy had made a video showing how it compared.  I think Dave may have made one as well.   You may want to try searching YT and see what's out there.  It's an old meter and many people have looked at it. 

Quote
Now that you made your wife to be the standard switch-feeling tester, it is a pity that you didn't show her the dt830 meter.
I didn't want to waste too much of her time but thought it was interesting that the Fluke 87V and UNI-T shown were both subjected to the 50,000 cycle life test and still have a better feel than the Keysight.   I never would have guessed she would like the BM869s.  Many people complain about how tight the switch is and the small knob.
[/quote]

Possibly the waterproof washer is the problematic part. Still, nex time show her the dt830 as well, just to have an objective oppinion :)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 03:33:24 pm
The SW generally works well for me (although I am on Windows 8 and not the newfangled 10), but the biggest annoyance is that is requires MS Office installed for any reporting/export functions. That is a PITA as I haven't installed MS Office in years in my PCs (I use some really excellent clones such as the Softmaker Freeoffice).
That may be why the report generator locks up.   I have Office installed.... 97!   :-DD   I refuse to change it as IMO, it started going down hill after this.  Anytime I have to use the latest Office tools today, part of my soul dies.   

Do you find that the system will glitch as I saw for longer captures?   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 03:37:47 pm

I'm not aware of any meters I have that are perfect.  If you feel there were, let me know which and I can have another look.   It is very possible that someone has a specific case they were running and I had meters that would handle it but let's be clear that doesn't suggest they wouldn't have other problems.   As shown in the photo, you could see that Keysight is no exception.   
I did not state that any meter was perfect, it was only about this specific test. Maybe the extech was the only one with ac+dc mV scale which passed it.

You would have to be more specific as I've covered a lot of ground. 

Quote
Possibly the waterproof washer is the problematic part. Still, nex time show her the dt830 as well, just to have an objective oppinion :)
I don't think that's going to happen any time soon but you are certainly free to ask your wife to run what ever test you like. 
Title: Re: Handheld meter robustness testing
Post by: Neutrion on August 10, 2022, 05:15:35 pm
To be more specific:
Pulled out my favorite meter of all time, the lime green TIP 194 II.  Now keep in mind this meter is currently damaged and has high leakage on one of the controllers port pins that effects the resistance measurements. 

In DCmV the meter over ranges at +/-500mV. 
In ACmV the meter over ranges at 1.417Vp-p or again 500mV RMS (60Hz sinewave)

With 490mVRMS biased with 400mV DC, both the AC and DC  millivolts readings are correct. 
Raising the DC bias to 499.9mV with 490mV RMS applied, the meter provides the correct readings for both.
Next I apply 600mV of bias to our 490mV RMS signal and of course the DCmV reading is now out of range.  But the ACmV reading is now effected again with no indication that there is a problem.   With 1VDC bias the ACmV is all the way down to 374mV.

The TPI 194II does support the AC+DC and is a tri-display.  But sadly this is not supported in mV ranges.  It's too bad I could not get a controller to replace the one on the meter.  I would have then attempted to improve it like I show with that low end UT61E. 

**********************************************************************************************
Looking at the Extech EX540
In DCmV the meter over ranges at +/-412mV. 
In ACmV the meter over ranges at 1.168Vp-p or again 412mV RMS (60Hz sinewave)

With 409mVRMS biased with 400mV DC, both the AC and DC millivolts readings are correct. 
Raising the DC bias to 500mV, the meter over ranges on the DCmV but there is a slight effect on the ACmV.
With 1VDC bias the ACmV is down to 399mV which is better than the TPI 194 II but it's an error and there again is no indication that there is a problem. 

This meter also supports AC+DC calculations and appears to show an over range for any combination that goes above 412mV. 

**********************************************************************************************
And I'm sure everyone wants to know the UNI-Ts top of the line UT181A does.  Again this meter was damaged like the TPI with one hit from the grill starter.  I was able to repair it and made some pretty drastic mods to the PCB.  This meter is not original but I do not believe I changed anything that would effect this test. 

In DCmV the meter over ranges at +/-612mV. 
In ACmV the meter over ranges at 1.731Vp-p or again 4612mV RMS (60Hz sinewave)

With 610mVRMS biased with 600mV DC, both the AC and DC millivolts readings are correct.
Raising the DC bias to 700mV, the meter over ranges on the DCmV but the ACmV is correct. 
With 1VDC bias the ACmV is down to 587mV and again there is no indication that there is a problem. 

This meter will calculate AC+DC and has a tri-display.  In this mode with the same 1VDC bias, the AC+DC and mVDC are both over ranged but the mVAC shows the 587mVAC which is of course not correct.  But if the OL were not enough to sway the user into thinking there may be a problem with their measurement, they go one step further and enable the yellow triangle with the lightning bolt.   Still, really it's not full proof and the ACmV should show an error as well or you just know someone is going to trust that number...

**********************************************************************************************

Scott's going to ask about the Fluke 97.  That's a special snowflake as it auto ranges both the AC and DC values.  You exceed the mV range, it will switch.


I don't disagree with the OP that there is a problem with some meters showing inaccurate results under certain conditions without any warning to the user.  Hopefully running these few meters shows that this is not something unique to one brand.
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 10, 2022, 05:34:07 pm
Sorry for the late reply. It's been a long day. A inverter drive I was using decided to give up and released some magic smoke, which is quite strange since we were only running it at no more than 10% of its rated power.

I'm surprised you would consider using a 2-wire approach below 10.

I agree using the 4-wire method is more appropriate. This is a side project and the support we can get is quite limited. We need something that can log the measurement automatically. It is either this or an old general purpose data logger. We do have some Keithley bench meters but we don't have any GPIB compatible PC to log the data. Hopefully the situation will change soon, if my colleague can get some funding.

When using the this meter, I will do some software tricks to improve the measurement.

That sounds interesting. I wonder if you could kindly share some details about these tricks?

I would expect what you are asking to be a paper study more than anything.

Not purely on paper. I would say this is a preliminary experiment to test the viability of liquid hydrogen cooling. However it is still far away from full scale experiment or even a technological demonstrator.

Shown after 7 hours with a 40R0000 0.005% +/-1ppm S102K attached.   Meter just setting on  my desk in open air (no temp control).   After 3 hours, something happens that we see a spike down to 1.239 ohms.  There is nothing going on during this time.  Office is closed off.   So I am going to suggest the software/firmware/hardware has a problem.      Zooming into this area, and ignoring the glitch we can see the meter changes 2 counts.   I have a low tempco 0.5ohm I'll attach and let it run for the day.

Thanks for sharing these. The glitch looks similar to what I experienced before on a Keithley 2700. Other than that the drift doesn't look so bad. Definitely better than my Gossen calibrator. Did you connect the resistor directly to the banana socket?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 05:55:39 pm
To be more specific:
Pulled out my favorite meter of all time, the lime green TIP 194 II.  Now keep in mind this meter is currently damaged and has high leakage on one of the controllers port pins that effects the resistance measurements. 

In DCmV the meter over ranges at +/-500mV. 
In ACmV the meter over ranges at 1.417Vp-p or again 500mV RMS (60Hz sinewave)

With 490mVRMS biased with 400mV DC, both the AC and DC  millivolts readings are correct. 
Raising the DC bias to 499.9mV with 490mV RMS applied, the meter provides the correct readings for both.
Next I apply 600mV of bias to our 490mV RMS signal and of course the DCmV reading is now out of range.  But the ACmV reading is now effected again with no indication that there is a problem.   With 1VDC bias the ACmV is all the way down to 374mV.

The TPI 194II does support the AC+DC and is a tri-display.  But sadly this is not supported in mV ranges.  It's too bad I could not get a controller to replace the one on the meter.  I would have then attempted to improve it like I show with that low end UT61E. 

**********************************************************************************************
Looking at the Extech EX540
In DCmV the meter over ranges at +/-412mV. 
In ACmV the meter over ranges at 1.168Vp-p or again 412mV RMS (60Hz sinewave)

With 409mVRMS biased with 400mV DC, both the AC and DC millivolts readings are correct. 
Raising the DC bias to 500mV, the meter over ranges on the DCmV but there is a slight effect on the ACmV.
With 1VDC bias the ACmV is down to 399mV which is better than the TPI 194 II but it's an error and there again is no indication that there is a problem. 

This meter also supports AC+DC calculations and appears to show an over range for any combination that goes above 412mV. 

**********************************************************************************************
And I'm sure everyone wants to know the UNI-Ts top of the line UT181A does.  Again this meter was damaged like the TPI with one hit from the grill starter.  I was able to repair it and made some pretty drastic mods to the PCB.  This meter is not original but I do not believe I changed anything that would effect this test. 

In DCmV the meter over ranges at +/-612mV. 
In ACmV the meter over ranges at 1.731Vp-p or again 4612mV RMS (60Hz sinewave)

With 610mVRMS biased with 600mV DC, both the AC and DC millivolts readings are correct.
Raising the DC bias to 700mV, the meter over ranges on the DCmV but the ACmV is correct. 
With 1VDC bias the ACmV is down to 587mV and again there is no indication that there is a problem. 

This meter will calculate AC+DC and has a tri-display.  In this mode with the same 1VDC bias, the AC+DC and mVDC are both over ranged but the mVAC shows the 587mVAC which is of course not correct.  But if the OL were not enough to sway the user into thinking there may be a problem with their measurement, they go one step further and enable the yellow triangle with the lightning bolt.   Still, really it's not full proof and the ACmV should show an error as well or you just know someone is going to trust that number...

**********************************************************************************************

Scott's going to ask about the Fluke 97.  That's a special snowflake as it auto ranges both the AC and DC values.  You exceed the mV range, it will switch.


I don't disagree with the OP that there is a problem with some meters showing inaccurate results under certain conditions without any warning to the user.  Hopefully running these few meters shows that this is not something unique to one brand.

As I read it again, each meter had problems.  Maybe you were not understanding what I had posted.   

One side note, the TPI 194II has since been repaired.  Well, I replaced the damaged IC.  It was never aligned after this but at least now throws up some OKish sort of numbers.     

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 06:12:26 pm
Sorry for the late reply. It's been a long day. A inverter drive I was using decided to give up and released some magic smoke, which is quite strange since we were only running it at no more than 10% of its rated power.

I'm surprised you would consider using a 2-wire approach below 10.

I agree using the 4-wire method is more appropriate. This is a side project and the support we can get is quite limited. We need something that can log the measurement automatically. It is either this or an old general purpose data logger. We do have some Keithley bench meters but we don't have any GPIB compatible PC to log the data. Hopefully the situation will change soon, if my colleague can get some funding.

When using the this meter, I will do some software tricks to improve the measurement.

That sounds interesting. I wonder if you could kindly share some details about these tricks?

I would expect what you are asking to be a paper study more than anything.

Not purely on paper. I would say this is a preliminary experiment to test the viability of liquid hydrogen cooling. However it is still far away from full scale experiment or even a technological demonstrator.

Shown after 7 hours with a 40R0000 0.005% +/-1ppm S102K attached.   Meter just setting on  my desk in open air (no temp control).   After 3 hours, something happens that we see a spike down to 1.239 ohms.  There is nothing going on during this time.  Office is closed off.   So I am going to suggest the software/firmware/hardware has a problem.      Zooming into this area, and ignoring the glitch we can see the meter changes 2 counts.   I have a low tempco 0.5ohm I'll attach and let it run for the day.

Thanks for sharing these. The glitch looks similar to what I experienced before on a Keithley 2700. Other than that the drift doesn't look so bad. Definitely better than my Gossen calibrator. Did you connect the resistor directly to the banana socket?

The resistor is mounted inside some insulation with banana connectors and plugged directly into the meter.  I am doing the same with the 0.5ohm.  The tempco for that part is not near as good and I am expecting more drift.   I may have some more stable parts if you feel there is something useful to be gained from running them.   

When looking at low resistance (ohm),  I will typically wear gloves and clean the parts with Proclean or methanol.  I will normally do a 2-point cal first.  Even though the equipment is under calibration,  I keep a set of standards on-hand that are not in the calibration system,  just for a sanity check.   I mark where I am going to measure from and always repeat on that location for every measurement.   My software will make multiple measurements waiting for the standard deviation to fall below a certain criteria while the parts become stable.   Some times I will handle the parts with tweezers to avoid transferring my body heat into the parts and speeding things up.   Once stable, I will take several more readings.   I normally automate this so it's not as bad as it seems.  I am a fan of the beach towel as well to remove air currents.   

I would imagine all basic stuff for people attempting to tighten up their measurements. 

I'll let that resistor run a few more hours then post the data for it.   Maybe from there, you can decide if there is something else you would like to see. 
Title: Re: Handheld meter robustness testing
Post by: Neutrion on August 10, 2022, 07:35:11 pm
To be more specific:
Pulled out my favorite meter of all time, the lime green TIP 194 II.  Now keep in mind this meter is currently damaged and has high leakage on one of the controllers port pins that effects the resistance measurements. 

In DCmV the meter over ranges at +/-500mV. 
In ACmV the meter over ranges at 1.417Vp-p or again 500mV RMS (60Hz sinewave)

With 490mVRMS biased with 400mV DC, both the AC and DC  millivolts readings are correct. 
Raising the DC bias to 499.9mV with 490mV RMS applied, the meter provides the correct readings for both.
Next I apply 600mV of bias to our 490mV RMS signal and of course the DCmV reading is now out of range.  But the ACmV reading is now effected again with no indication that there is a problem.   With 1VDC bias the ACmV is all the way down to 374mV.

The TPI 194II does support the AC+DC and is a tri-display.  But sadly this is not supported in mV ranges.  It's too bad I could not get a controller to replace the one on the meter.  I would have then attempted to improve it like I show with that low end UT61E. 

**********************************************************************************************
Looking at the Extech EX540
In DCmV the meter over ranges at +/-412mV. 
In ACmV the meter over ranges at 1.168Vp-p or again 412mV RMS (60Hz sinewave)

With 409mVRMS biased with 400mV DC, both the AC and DC millivolts readings are correct. 
Raising the DC bias to 500mV, the meter over ranges on the DCmV but there is a slight effect on the ACmV.
With 1VDC bias the ACmV is down to 399mV which is better than the TPI 194 II but it's an error and there again is no indication that there is a problem. 

This meter also supports AC+DC calculations and appears to show an over range for any combination that goes above 412mV. 

**********************************************************************************************
And I'm sure everyone wants to know the UNI-Ts top of the line UT181A does.  Again this meter was damaged like the TPI with one hit from the grill starter.  I was able to repair it and made some pretty drastic mods to the PCB.  This meter is not original but I do not believe I changed anything that would effect this test. 

In DCmV the meter over ranges at +/-612mV. 
In ACmV the meter over ranges at 1.731Vp-p or again 4612mV RMS (60Hz sinewave)

With 610mVRMS biased with 600mV DC, both the AC and DC millivolts readings are correct.
Raising the DC bias to 700mV, the meter over ranges on the DCmV but the ACmV is correct. 
With 1VDC bias the ACmV is down to 587mV and again there is no indication that there is a problem. 

This meter will calculate AC+DC and has a tri-display.  In this mode with the same 1VDC bias, the AC+DC and mVDC are both over ranged but the mVAC shows the 587mVAC which is of course not correct.  But if the OL were not enough to sway the user into thinking there may be a problem with their measurement, they go one step further and enable the yellow triangle with the lightning bolt.   Still, really it's not full proof and the ACmV should show an error as well or you just know someone is going to trust that number...

**********************************************************************************************

Scott's going to ask about the Fluke 97.  That's a special snowflake as it auto ranges both the AC and DC values.  You exceed the mV range, it will switch.


I don't disagree with the OP that there is a problem with some meters showing inaccurate results under certain conditions without any warning to the user.  Hopefully running these few meters shows that this is not something unique to one brand.

As I read it again, each meter had problems.  Maybe you were not understanding what I had posted.   

One side note, the TPI 194II has since been repaired.  Well, I replaced the damaged IC.  It was never aligned after this but at least now throws up some OKish sort of numbers.     

So  again: The problem is when a meter  does not give any indication on the ac+dc mV scale (dc coupled)that either AC or DC overranged, and displaying false ac values.
And the extech EX540 shows that it overranged. It was not PERFECT, but it gave some indications.
The problem was NOT whether the meter can read AC perfectly with unlimited DC bias which is usually specified (a least in case of Brymen) that it can not. The problem is the missing of any kind of indication that the DC bias is overranged to take the AC values with a grain of salt.

Joe Smith also didn't like  this with a Fluke:

What about Fungus's favorite meter, the Fluke 101?  Fungus recommended that meter to me for the very first $50 shoot em up test I ran and it cam out a clear winner.  The one I have has never been apart. Not even for a peak!  It has survived every thing I have thrown at it to date and works great. It's an averaging meter but again not a big deal for what we are doing.  Surely this is our perfect meter!

It has a mVAC range and appears to over range at 660.0mV AC RMS 60Hz sinewave.  Injecting 1.7VACp-p meter reads roughly 600mV as expected.  Adding 300mV DC of bias, the meter reads 13mV high.  With 600mV bias, the meter reads 10mV low.  At 1VDC bias, its now reading 480mV.  At 1.9VDC bias, its all the way down to 85mV and no indication there is anything wrong!  Big fail for the Fluke 101!

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 09:12:43 pm
So  again: The problem is when a meter  does not give any indication on the ac+dc mV scale (dc coupled)that either AC or DC overranged, and displaying false ac values.
And the extech EX540 shows that it overranged. It was not PERFECT, but it gave some indications.
The problem was NOT whether the meter can read AC perfectly with unlimited DC bias which is usually specified (a least in case of Brymen) that it can not. The problem is the missing of any kind of indication that the DC bias is overranged to take the AC values with a grain of salt.

Joe Smith also didn't like  this with a Fluke:

What about Fungus's favorite meter, the Fluke 101?  Fungus recommended that meter to me for the very first $50 shoot em up test I ran and it cam out a clear winner.  The one I have has never been apart. Not even for a peak!  It has survived every thing I have thrown at it to date and works great. It's an averaging meter but again not a big deal for what we are doing.  Surely this is our perfect meter!

It has a mVAC range and appears to over range at 660.0mV AC RMS 60Hz sinewave.  Injecting 1.7VACp-p meter reads roughly 600mV as expected.  Adding 300mV DC of bias, the meter reads 13mV high.  With 600mV bias, the meter reads 10mV low.  At 1VDC bias, its now reading 480mV.  At 1.9VDC bias, its all the way down to 85mV and no indication there is anything wrong!  Big fail for the Fluke 101!
:palm: :palm: :palm:   While I would have thought with all of my other comments about none of this being any sort of concern for me everyone would have recognized the heavy sarcasm.   :-DD

I would imagine I could find a case where I drive that Extech to 0 with voltage applied, just like I have shown with others.  Again, more entertaining than anything but of no practical value, at least to me. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 09:19:32 pm
I'll let that resistor run a few more hours then post the data for it.   Maybe from there, you can decide if there is something else you would like to see.

Showing the 0.5ohm part over the 8 hours.  Looks like 8 counts.   Again, this part isn't near the same specs as the first 40 ohm I ran.   Nice thing is there was no glitches in the data this time. 

Let me know if you would still see any value in looking at it with a DC reference.  I have a very old Fluke 731B but outside of that I really don't have much for the way of standards.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 10, 2022, 09:27:17 pm
Do you find that the system will glitch as I saw for longer captures?
Glitch? I haven't seen any issues. Long captures were not a problem as shown below (albeit with my U1273A)

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1562605)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 10, 2022, 10:15:31 pm
Do you find that the system will glitch as I saw for longer captures?
Glitch? I haven't seen any issues. Long captures were not a problem as shown below (albeit with my U1273A)

As in that first shot.  Keep in mind you are only three minutes of data.  I was showing 7 hours.   That glitch was after 3 hours with a 10 second sample rate. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 11, 2022, 01:05:56 pm
I let the meter run for about 14 hours with a 1mV source attached.  Again, the meter was just sitting on my desk without any temperature control.   This time the sample rate was set to 1Hz.    Once again, we see a downward glitch.   Also, like the last time this is during the night with everything shut down.

If we ignore the glitch and zoom into the baseline, it looks like it drifts about 8 counts.  Keeping in mind these measurements all include the standards and I am not suggesting this is all the meters doing.   

Let me know if this answers your question.  I am not happy seeing these two glitches in the data.  The fact I have seen it twice now and once with nothing more than a resistor attached, it seems there is something wrong with the software/firmware/meter as this isn't something I would expect to see.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 11, 2022, 10:48:42 pm
Do you find that the system will glitch as I saw for longer captures?
Glitch? I haven't seen any issues. Long captures were not a problem as shown below (albeit with my U1273A)

As in that first shot.  Keep in mind you are only three minutes of data.  I was showing 7 hours.   That glitch was after 3 hours with a 10 second sample rate.
That was an older capture, but the total was more than twenty minutes of data without a glitch (not three). I can retry with the U1282A, but I won't promise a runlength of hours.
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 11, 2022, 11:03:40 pm
I let the meter run for about 14 hours with a 1mV source attached.  Again, the meter was just sitting on my desk without any temperature control.   This time the sample rate was set to 1Hz.    Once again, we see a downward glitch.   Also, like the last time this is during the night with everything shut down.

If we ignore the glitch and zoom into the baseline, it looks like it drifts about 8 counts.  Keeping in mind these measurements all include the standards and I am not suggesting this is all the meters doing.   

Let me know if this answers your question.  I am not happy seeing these two glitches in the data.  The fact I have seen it twice now and once with nothing more than a resistor attached, it seems there is something wrong with the software/firmware/meter as this isn't something I would expect to see.

Thanks for sharing this. I guess the voltage across the resistor during the resistance test was much higher than 1 mV, so the drift wasn't picked up. Do you think if you could do another resistance test with the 0.5 Ohm resistor to see if the drift would appear?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 11, 2022, 11:25:00 pm
Thanks for sharing this. I guess the voltage across the resistor during the resistance test was much higher than 1 mV, so the drift wasn't picked up. Do you think if you could do another resistance test with the 0.5 Ohm resistor to see if the drift would appear?

Guessing that's a typo as I have shown a 40 and 0.5 ohm already.   

That was an older capture, but the total was more than twenty minutes of data without a glitch (not three). I can retry with the U1282A, but I won't promise a runlength of hours.

If you have saved other collections that were longer, looks like you can import them.     
***
Also, I am using software version 3.1.51130.01 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 12, 2022, 02:14:10 am
Spent a few minutes, literally, to put a simple program together that just reads the meter and plots the data at 1Hz.  Shown with the 40ohm inserted.  Note that they send up one more digit.  I'll let this run overnight and see if a glitch shows up.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 12, 2022, 01:05:46 pm
After letting the Keysight U1282A run with the 40 ohm resistor,  shown is roughly 10 hours of data collected with my simple program.  Once again we can see the problem.  Zooming into both glitches, they are a single data point.   While it could be the driver, I think this rules out their software.   

Odd such a high end meter would have such a problem.  Surely Keysight tests their products.  It would be nice to know if it was unique to this particular meter. 
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 12, 2022, 02:06:57 pm
I tried on mine, it is a fairly old 1282 with the original firmware:

(http://lygte-info.dk/pic/cpf6/dropout.png)

Dropout after 20 minutes, but to 5 not to 0.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 12, 2022, 02:32:37 pm
Thanks for repeating this test.   Going back and looking at the first time I ran it, they both dropped to around 1.5.   So not exactly 0.  So far, every time I have seen it glitch, it is always towards a lower value. 

I'm surprised they wouldn't have caught something like this but then again, that counter spec doesn't give me any comfort.   

With them recently sending that one reviewer a meter, they may be able to provide them feedback. 

Chance92 and others would have to decide if its going to be a problem for them.   I can imagine if you are running a long term experiment and the signal is not stable as you expect, then your spending time trying to track down if it's something on your end or the equipment, that will get old fast.   I guess, just something else to be aware of if you buy one of these meters. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 12, 2022, 02:49:47 pm
Have you tried this test with any of your Brymens?

It would be interesting to see the signal at that point to see if it's data corruption or if the meter is sending incorrect data.
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 12, 2022, 02:50:31 pm
Thanks for repeating this test.   Going back and looking at the first time I ran it, they both dropped to around 1.5.   So not exactly 0.  So far, every time I have seen it glitch, it is always towards a lower value. 

I'm surprised they wouldn't have caught something like this but then again, that counter spec doesn't give me any comfort.   

With them recently sending that one reviewer a meter, they may be able to provide them feedback. 

Chance92 and others would have to decide if its going to be a problem for them.   I can imagine if you are running a long term experiment and the signal is not stable as you expect, then your spending time trying to track down if it's something on your end or the equipment, that will get old fast.   I guess, just something else to be aware of if you buy one of these meters.

Thank you very much for taking the time to do these tests. A glitch like this is indeed surprising. I just looked up the firmware update. The latest version is 1.05, which came out in 2017. Release notes indicate they probably haven't address this issue so far.
https://www.keysight.com/us/en/assets/9018-18550/release-notes/9018-18550.txt?success=true (https://www.keysight.com/us/en/assets/9018-18550/release-notes/9018-18550.txt?success=true)
Quote
Firmware revision updates:-


Version 1.02
-    Initial release

Version 1.03 fixes several issues present in the previous release.
-   Change microcontroller sampling period from 25ms to 12.5ms.
-    Bug fix for CAP+NULL+AUTO wrong range.
-   Faster LED response for continuity.

Version 1.04 fixes several issues present in the previous release.
-   Change Ampere calibration limits from 70% to 80% to solve       production calibration fallout.
-   Improve Autozero limitation by recalculating Autozero and not       loading Autozero default value when inputs are OL.
-   Reset OP1 & AD1 before reading Autozero.
-   Zero Timer change from 4.2 seconds to 6.2 seconds.

Version 1.05 includes the following fix.
-   Disables DC Filter during measurement at ACmV mode.


Have you seen anything like this on other meters you have tested?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 12, 2022, 03:42:20 pm
Have you tried this test with any of your Brymens?

It would be interesting to see the signal at that point to see if it's data corruption or if the meter is sending incorrect data.

I have not.

Have you seen anything like this on other meters you have tested?

Normally I am using my old HP34401A with GPIB and GPIB to Ethernet.  That system is very stable.   I saved a very old Fluke thermal RMS meter from the recycle and repaired it.  That meter was using RS232 and is again very stable.

The handhelds I have looked at are the UNI-T UT181A, the CEM DT-9939, Dave's 121GW, Fluke 189 and the Gossen Ultra (now Prime, go Gossen).   

I did have a few problems with the 121GW but from what I remember they were self induced.   It seems like there was a problem with recording to the SD card.  I was mostly using BLE.  Some of that may have been corrected by now.   

The CEM also has a problem (seen in the attached video).  The other meters were stable.

https://www.youtube.com/watch?v=Mkec-Eyhg7c (https://www.youtube.com/watch?v=Mkec-Eyhg7c)

Video showing some of these meters.
https://www.youtube.com/watch?v=e_YzwO62feQ (https://www.youtube.com/watch?v=e_YzwO62feQ)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 12, 2022, 07:26:35 pm
Here's the vintage Fluke I trash picked after my repairs.  Shown with a 60 ohm using 4-wire for 20 hours.  Again, this is using RS-242 to USB.  The whole setup is very stable and I would expect that Keysight to be the same.   

While this meter is very old, big, heavy... the specs are still very impressive.   You may want to consider trying to find an old working bench meter for your experiment.       
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on August 12, 2022, 08:42:17 pm
Have you tried this test with any of your Brymens?

It would be interesting to see the signal at that point to see if it's data corruption or if the meter is sending incorrect data.

I did long data logging of voltage with both BM525S in standalone mode and BM869S with a IR cable..
Never had any problems..
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2022, 12:48:36 am
Interesting post from a viewer attempting to show their U1282A will read up to 44MHz.  I am not sure what they are using for a termination, cables or connectors.   Nor do they do any sort of sweeps of the voltage or frequency so I really have little to go on.  They don't show the power up but the claim is it has the same firmware.  Maybe just luck of the draw, older hardware.   Still it's  a long way off from the 100MHz printed in the manual.   


https://www.youtube.com/watch?v=88TSvKQJe0g (https://www.youtube.com/watch?v=88TSvKQJe0g)
Title: Re: Handheld meter robustness testing
Post by: skander36 on August 13, 2022, 11:01:20 am
The meter is calibrated in January 2020. FW 01.05.
I have used a 50 ohm (50 cm long) cable. You can view attached the cable used. Worth mentioned that with normal cables I wasn't able to get more than 35 MHz.
The measurement is quite unstable and I need more trial and error rounds to achieve these value. Definitely not practical. 
I have obtained also max.  40 MHz from first try with an ADF4351 generator, rectangular waveform this time at about 950 mVpp (fixed value).
For me this meter was a little disapointing, because of long time needed when change between measuring domains. It was a surprise because the Agilent 1252A is one of the fastest multimeters that I have. 1282A became comparable faster if you switch to fast from settings but with a lower resolution.
This frequency measurement also show a weird behavior and a discrepancy beyween declarations (100 MHz) and reality.
Overal is a good meter because precission and resolution, long life of batteries, shock proof, but for me it is not a "daily driver" due to its slowness.
Better resolution for pics here : https://ibb.co/album/f4r0dp
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 13, 2022, 02:18:23 pm
Do you find that the system will glitch as I saw for longer captures?
Glitch? I haven't seen any issues. Long captures were not a problem as shown below (albeit with my U1273A)

As in that first shot.  Keep in mind you are only three minutes of data.  I was showing 7 hours.   That glitch was after 3 hours with a 10 second sample rate.
That was an older capture, but the total was more than twenty minutes of data without a glitch (not three). I can retry with the U1282A, but I won't promise a runlength of hours.
Ok, I put it to run while doing other things around the house. Indeed there was a glitch at around 40min mark for the U1282A.
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1564423)

I will probably test the U1273A and see if similar things happen, which might help isolate the issue to either the meter or the software.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2022, 02:28:09 pm
So no termination.  With the Arb set to 50 ohm, I am guessing the readout is then off by a factor of 2X,  or really 240mVpeak or 0.169 RMS.   

Still, with the one I have, using no termination, 200mm of  RG400, setting the RF generator to even 35MHz and changing the amplitude, I can find a sweet spot where it comes in.   This is why I was asking about you changing the frequency and amplitude in the video to give me some idea how well yours detects the signal. 

With  your second source, is that 950mVpp without the termination?   When I tried to square it up with the LVDS and PECL drive, it made no difference in how my meter behaved. 

Both are not good compared with what is stated but I'm surprised yours behaves differently, especially after rsjsouza's post showing the exact same error in the frequency I see with mine.   
Title: Re: Handheld meter robustness testing
Post by: skander36 on August 13, 2022, 03:03:01 pm
Second source - no termination.
The "video" is not a video, I just insert the picture in a video format and save as mp4 because youtube delete any post that contain a link to image hosting sites.
At 38 MHz it read 36,53 MHz.
For 44 MHz at 380 mvpp it show a variable value between 57-66 MHz.
I have no intention to make a video. I just wanted to show that it can read a higher value. In  my opinion this meter simply cannot read 100 MHz.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 13, 2022, 03:17:35 pm
So, the U1273A shows no glitch.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1564468)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2022, 04:02:06 pm
I will probably test the U1273A and see if similar things happen, which might help isolate the issue to either the meter or the software.

Thanks for double checking.  With HKJ and myself using two additional programs to talk with the meter and still seeing the problem, I doubt it's the software causing it.  Maybe the driver.  To help answer this, I used a dumb RS-232 IR adapter and sniffed the Keysight adapter while trying to connect.  I get the *IDN?   Trying it with LabView, I see the 0D0A terminator.  So nothing magic going on.  The old time IR adapter was then stuck on the U1282A meter and I started the logging.  I'm using an FTDI RS232-USB adapter so no Keysight software or driver.   

I have the same 40 ohm resistor attached and again collecting at 1sps.  I'll let it run for the afternoon and see if the glitch is still there.  If so, we are down to firmware and hardware.   I would be embarrassed if I had customers trying to solve my problems...


Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2022, 04:03:33 pm
So, the U1273A shows no glitch.

You may want to continue to let it run for the afternoon as well.   Doesn't hurt to make sure. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2022, 04:11:06 pm
Well, that was quick.  It's not a large dip but similar to the small one that I showed the last time.   I'll let it run but it's down to the meter now.  Good job Keysight! 

Title: Re: Handheld meter robustness testing
Post by: HKJ on August 13, 2022, 04:18:20 pm
It probably depends on range.
(http://lygte-info.dk/pic/cpf6/KeysightGlitch1.png)

A 100 ohm resistor (0.01%) and there is no huge glitches.
(http://lygte-info.dk/pic/cpf6/KeysightGlitch2.png)
Only a small one, where it dropped to 96ohms.

TC will not always show short glitches on the chart, there is not enough dots for it. but searching will find it and the range page list the absolute minimum value in the data.

I switched to a 10ohm resistor and got a large glitch again:
(http://lygte-info.dk/pic/cpf6/KeysightGlitch3.png)
Here it is -0.4164 ohm
Title: Re: Handheld meter robustness testing
Post by: TheAmmoniacal on August 13, 2022, 05:34:14 pm
Defpom's review is up.

Part 1

https://youtu.be/bFyJlMd35v0

Part 2

https://youtu.be/UgbDNE0KhhI
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 13, 2022, 08:21:00 pm
Well, that was quick.  It's not a large dip but similar to the small one that I showed the last time.   I'll let it run but it's down to the meter now.  Good job Keysight!

Hi Joe. Do you think if you could run it again with the min/max function enabled on the meter, so that we can see if this glitch would show on the display? This way we may be able to isolate the problem further.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 13, 2022, 08:47:09 pm
Well, that was quick.  It's not a large dip but similar to the small one that I showed the last time.   I'll let it run but it's down to the meter now.  Good job Keysight!

Hi Joe. Do you think if you could run it again with the min/max function enabled on the meter, so that we can see if this glitch would show on the display? This way we may be able to isolate the problem further.

So you're thinking just let the meter sit stand alone with min/max and see if it happens?  It does seem like a good idea.     
Title: Re: Handheld meter robustness testing
Post by: TheDefpom on August 13, 2022, 09:36:08 pm
Defpom's review is up.

Part 1

https://youtu.be/bFyJlMd35v0

Part 2

https://youtu.be/UgbDNE0KhhI

LOL, yes up, but not publicly published yet, I wish youtube would hide unlisted videos from public playlists until the video gets made public, oh well.

Enjoy the early access I guess !
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 12:50:49 am
Defpom's review is up.

Part 1

https://youtu.be/bFyJlMd35v0

Part 2

https://youtu.be/UgbDNE0KhhI

LOL, yes up, but not publicly published yet, I wish youtube would hide unlisted videos from public playlists until the video gets made public, oh well.

Enjoy the early access I guess !

Good to see you also see a similar problem with the counter.   Outside of what you have shown, did you try logging any data with the meter?   If so, are you seeing this same glitch we are showing above? 
Title: Re: Handheld meter robustness testing
Post by: TheDefpom on August 14, 2022, 04:11:35 am
There are a few features I haven't tried using yet, logging is one of them, I have a lot on at the moment so I don't know when I will get to look at that.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 04:42:09 am
There are a few features I haven't tried using yet, logging is one of them, I have a lot on at the moment so I don't know when I will get to look at that.
Lucky for me, logging requires very little of my time.  Basically set the meter up and walk away.  Well, I spend maybe an hour to put that simple program together, test their interface cable, then sort get it attached to the meter.    Watching grass grow, paint dry, kettle boil.... all much more exciting. 

Title: Re: Handheld meter robustness testing
Post by: TheAmmoniacal on August 14, 2022, 07:23:58 am
Defpom's review is up.

Part 1

https://youtu.be/bFyJlMd35v0

Part 2

https://youtu.be/UgbDNE0KhhI

LOL, yes up, but not publicly published yet, I wish youtube would hide unlisted videos from public playlists until the video gets made public, oh well.

Enjoy the early access I guess !

Oops, sorry about that - didn't even see they were unlisted before you mentioned it. Part 2 appeared in a recommended playlist on my TV, when I clicked to watch it, Part 1 was suggested just below it. Then just copied the links from my watch history.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 04:58:25 pm
I let the U1282A run for 25 hours using my software with the simple RS232 dumb IR cable and FTDI USB controller.  After that initial small glitch, the setup remained stable.   

Not being able to reproduce the glitch, I wonder if we are dealing with multiple problems.    I have increased the sample rate from 1sps to 4sps 5sps to see if it has any effect.   

***
correct brain fart...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 06:22:01 pm
Well, how things change....

So after changing the sample rate I captured another small glitch which first appeared to have an identical amplitude as the first.   Zooming in, they are close but not the same.   Then, shortly after I captured another large glitch.     

I want to point out that the 4sps is a mistake and should have been five.   Obviously Windows and Labview are going to have a timing error.  The measured jumps around +/-1mS.  So basically 5sps sample and the meter seems to keep up just fine.    After the large glitch, it's been stable.  I plan to continue to let it run. 

It's starting to look more and more like the meter has a problem (hardware and or firmware).   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 14, 2022, 06:30:23 pm
Well, how things change....

So after changing the sample rate I captured another small glitch which first appeared to have an identical amplitude as the first.   Zooming in, they are close but not the same.   Then, shortly after I captured another large glitch.     

I want to point out that the 4sps is a mistake and should have been five.   Obviously Windows and Labview are going to have a timing error.  The measured jumps around +/-1mS.  So basically 5sps sample and the meter seems to keep up just fine.    After the large glitch, it's been stable.  I plan to continue to let it run. 

It's starting to look more and more like the meter has a problem (hardware and or firmware).   

Joe just curious when u think it might be a hardware issue do u suspect the chypset at all?  Do any other meters based on the HY3131 have similar glitches?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 06:52:08 pm
Well, how things change....

So after changing the sample rate I captured another small glitch which first appeared to have an identical amplitude as the first.   Zooming in, they are close but not the same.   Then, shortly after I captured another large glitch.     

I want to point out that the 4sps is a mistake and should have been five.   Obviously Windows and Labview are going to have a timing error.  The measured jumps around +/-1mS.  So basically 5sps sample and the meter seems to keep up just fine.    After the large glitch, it's been stable.  I plan to continue to let it run. 

It's starting to look more and more like the meter has a problem (hardware and or firmware).   

Joe just curious when u think it might be a hardware issue do u suspect the chypset at all?  Do any other meters based on the HY3131 have similar glitches?

I think the only other meter I looked at with that Hycon chipset was the 121GW.  It's been so long since I looked at that meter, I'm not sure if they ever sorted out all the problems with it or not.   There were certainly problems when logging to the SD card but I don't remember there being any problems when using BLE.  I would think if its hardware, it is something in how the chipset is being used, not the IC itself.   

If old age has taught me anything when it comes to solving problems, stay data driven.  Don't let feelings cloud your judgement.  :-DD  We know the U1282A sends up ASCII data.   We are using a 40 ohm resistor and the meter sends up  something like: +4.00108000E+01.  There's no missing data that would get us to what we are seeing.    So far it appears random and can be reproduced without Keysight's software, drivers or interface cable.   

I changed the test program to switch between two sample rates every 10 samples to see if that has any effect.   

Personally, I blame this problem on those that voted for this meter!!  You knew dam well I wouldn't just unbox it and give it five stars!!   :-DD :-DD :-DD


 
Title: Re: Handheld meter robustness testing
Post by: 25 CPS on August 14, 2022, 07:03:12 pm
Defpom's review is up.

Part 1

https://youtu.be/bFyJlMd35v0

Part 2

https://youtu.be/UgbDNE0KhhI

I'm in the process of watching Part 1 now.

Right off the top though, he says that his U1282A was supplied by Keysight.  If there's differing performance, could it be possible the sample unit specifically selected from a group of meters to make sure a good one was sent out for review vs. whatever you'd end up with by purchasing through regular retail channels?

The second question is why?  That one I truly don't understand.  If Keysight's going to be so painful to deal with for individuals and small businesses, why send meters out for review on YouTube?

Maybe I'll lash up my U1282A which was a used eBay purchase up to a laptop since I've got the Keysight software running on one and several of the interface cables and let it rip for a few days when I'm on some crappy shift work and then look at the results after.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 07:35:17 pm
Right off the top though, he says that his U1282A was supplied by Keysight.  If there's differing performance, could it be possible the sample unit specifically selected from a group of meters to make sure a good one was sent out for review vs. whatever you'd end up with by purchasing through regular retail channels?

That's always been a concern for me as well and why I will normally try to procure them the way anyone else on this forum would.   It's also why I will not use my professional background when attempting to open a dialog with a company.  I want people to know as a hobbyist how the company may treat them.   Of course, there have been cases where I have looked at preproduction meters.  In these cases, you get to see things as they evolve which I find rather interesting.   

The second question is why?  That one I truly don't understand.  If Keysight's going to be so painful to deal with for individuals and small businesses, why send meters out for review on YouTube?

With the timing, I still think it's damage control.    :-DD   In my case, there's no income from the channel.  I don't ask viewers to subscriber, ring some bell or consider becoming a Patreon.  I don't even run ads.  There's nothing even setup to take in money if I wanted to.   A total loss on my part.  On the flip side,  don't expect to see any basic unboxing 5-star review videos anytime soon!   :-DD
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 14, 2022, 08:32:12 pm
I think the only other meter I looked at with that Hycon chipset was the 121GW.

I expect that the BM78x series is the same chipset, but alas it also has no data collection abilities.

If old age has taught me anything when it comes to solving problems, stay data driven.  Don't let feelings cloud your judgement.  :-DD 

So very true. It's really hard to keep feelings from clouding judgement... Especially in the current atmosphere where anyone can start a youtube channel and instantly be an "Expert" on whatever... Data is all that more important to be able to sort the truth from the opinion.

Personally, I blame this problem on those that voted for this meter!!  You knew dam well I wouldn't just unbox it and give it five stars!!   :-DD :-DD :-DD

I think I am one of those to blame then.  :-DD. I recently was making the decision between a BM789 or a U1272A... I ended up picking the Brymen and based on your reviews and the current discussions about Keysight not caring about non-business customers I think I made the correct choice.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 09:27:56 pm
The Keysight has been running with the two sample rates without a single glitch.  However, I think I now know how to replicate the problem at will.   I need to do a little more work to get some proof but my confidence is increasing.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 14, 2022, 10:19:37 pm
Now we are getting somewhere.   

Title: Re: Handheld meter robustness testing
Post by: Trader on August 14, 2022, 11:35:16 pm
I got to run it on the signal generator; up to -30dBm I got about 19MHz; at at -20dBm I got 25MHz, -10dBm I got about 27MHz and at 0dBm I got 31MHz.

Same here, 31.000MHz is the max freq with accuracy I got it.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 04:10:26 am
We are using a 40 ohm resistor and the meter sends up  something like: +4.00108000E+01.  There's no missing data that would get us to what we are seeing.    So far it appears random and can be reproduced without Keysight's software, drivers or interface cable.   

I changed the test program to switch between two sample rates every 10 samples to see if that has any effect.   

Personally, I blame this problem on those that voted for this meter!!  You knew dam well I wouldn't just unbox it and give it five stars!!   :-DD :-DD :-DD

Joe and Defpom videos showed that this DMM is so damn good and accurate, I really don't care about the 31MHz limitation, this is a secondary feature, just to compare, the Fluke 289 is only up to 1MHz, 1Vpp.

That Log glitch maybe could be fixed via Firmware, not a big deal since most people only use the Max/Min for a couple of seconds or minutes.

BTW, Congrats to Defpom, awesome tests, try to get a Fluke 289 to do the same tests.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 15, 2022, 11:58:43 am
We are using a 40 ohm resistor and the meter sends up  something like: +4.00108000E+01.  There's no missing data that would get us to what we are seeing.    So far it appears random and can be reproduced without Keysight's software, drivers or interface cable.   

I changed the test program to switch between two sample rates every 10 samples to see if that has any effect.   

Personally, I blame this problem on those that voted for this meter!!  You knew dam well I wouldn't just unbox it and give it five stars!!   :-DD :-DD :-DD

Joe and Defpom videos showed that this DMM is so damn good and accurate, I really don't care about the 31MHz limitation, this is a secondary feature, just to compare, the Fluke 289 is only up to 1MHz, 1Vpp.

That Log glitch maybe could be fixed via Firmware, not a big deal since most people only use the Max/Min for a couple of seconds or minutes.

BTW, Congrats to Defpom, awesome tests, try to get a Fluke 289 to do the same tests.

 :-DD :-DD  Outside of a basic checkout,  I haven't done anything with it.   I would hope all products would meet the manufacture's claims.  In the case of the U1282A, we are already seeing there are problems.   Is their lack of attention to detail at this level an indicator of what's to come?   We know from the last Keysight meter I looked at, their choice of materials led to a spring failure.  The input protection was also on the weak side compared with other products. 

I won't pretend to speak for the majority  but certainly agree that for you personally, much of what I show may not be a big deal.   I would hope the majority buy products that meet their personal needs and based those decisions on the specifications the manufacture supplies.  My goal is to go beyond their specs and push the meters to failure to get some idea how electrically robust they are.   Again, may hold little interest to you personally but there are a few of us who like to see how the products compare on a level playing field. 
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 02:23:53 pm
My goal is to go beyond their specs and push the meters to failure to get some idea how electrically robust they are.

I follow your videos, yes, I have an interest in these minimal details and in the electronic robustness and safety. I already have "an idea" (based on other videos and 7+ years on market) that the U1282A will be good on these tests.

I just think that some issues don't deserve so much punishment or a brand judgment if those features are not so used or important. I didn't see anyone judging the entire Brymen company just because of the issues in the 869s, or the entire Gossen Metrawatt because of the Critical Failure in the M248B, even high-end Flukes have some issues.

Rarely someone would buy a DMM just because can measure 100MHz frequencies. The log glitch is more important, maybe could be fixed by firmware.

I hope that Keysight uses your tests to improve their product, thank you so much for your efforts, and keep moving forward with the new tests.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 15, 2022, 03:49:38 pm
I'm not sure where these Keysight meters fit into things.

If I wanted a really "analytical" meter I'd go with the Fluke 289. It shows a lot of information on screen and doesn't seem to do anything badly.

If I anything over 100kHz (or even 20kHz...) I'd probably be using an oscilloscope, not a multimeter.

For anything under 100kHz I'm not sure why anybody would pay 3x more than a Brymen.

That's just me though. What would the owners say is the killer feature of these meters? Why did you buy one?

(not trying to derail the thread, I promise I'll sit and listen quietly)
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 04:17:35 pm
I'm not sure where these Keysight meters fit into things.

If I wanted a really "analytical" meter I'd go with the Fluke 289. It shows a lot of information on screen and doesn't seem to do anything badly.

If I anything over 100kHz (or even 20kHz...) I'd probably be using an oscilloscope, not a multimeter.

For anything under 100kHz I'm not sure why anybody would pay 3x more than a Brymen.

That's just me though. What would the owners say is the killer feature of these meters? Why did you buy one?

(not trying to derail the thread, I promise I'll sit and listen quietly)

I'm not sure if Fluke 289 has more features than Keysight U1282A, but both complement each other.

U1282A 4-batteries last more than 1000 hours, the 289 6-batteries won't last 10% of that.

This question also can be applied to some Gossen's, Chauvin Arnoux (Metrix), and even Greenlee, Voltcraft, etc...

ps.: Discontinued Fluke 189, 4-batteries last only 72 hours (maybe 1-week of work, LOL).
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 04:19:54 pm
I also recommend these 2 excellent reviews of Keysight U1282A:

https://community.element14.com/products/roadtest/rv/roadtest_reviews/109/roadtest_the_keysigh_6

https://lygte-info.dk/review/DMMKeysight%20U1282A%20UK.html

(https://community.element14.com/cfs-file/__key/roadtestreviewfiles/eb55809c811147799ebeb7573e7b8ad3/3326.contentimage_5F00_156972.png)

(https://lygte-info.dk/pic/Keysight/U1282A/DMMschema.png)
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 15, 2022, 05:04:52 pm
I'm not sure if Fluke 289 has more features than Keysight U1282A, but both complement each other.

To compare features on high-end meters I made this: https://lygte-info.dk/info/DMMHigh-end%20UK.html (https://lygte-info.dk/info/DMMHigh-end%20UK.html)
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 15, 2022, 05:21:05 pm
U1282A 4-batteries last more than 1000 hours, the 289 6-batteries won't last 10% of that.

Datasheet says "up to 800": https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf)

What I mean by "analytical" is things like min/max measurements. The 289 will show min/max/actual on screen simultaneously (or min/max/avg). That seems a lot more useful than pressing buttons to see each one.

Look at the image you posted - the 289 just shows the info much better:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1565968;image)
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 15, 2022, 05:41:30 pm
Look at the image you posted - the 289 just shows the info much better:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1565968;image)
It is a tradeoff, where display complexity brings convenience at the expense of battery life and contrast (at least on the Fluke). The U1282A is closer to your typical portable multimeter (7-segment numerical display) than the graphical ones, so it is not necessarily a detriment to it.

The fact it has the interface cable included (expensive options on Gossen, Fluke and perhaps others) and a multitude of logging and triggers is one of its raison d'étre. Also, it is mechanically quite robust (Dave went through a canyon with it) where I suspect the other two would fail miserably (understandable, and they were not designed for such conditions). Add to this the external remote control, the waveform output, the 30+MHz frequency measurement and you can get a fit for it. :-+
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 05:54:05 pm
Datasheet says "up to 800": https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf)
Look at the image you posted - the 289 just shows the info much better:

Datasheet says 60k counts, but is 66k.  Battery by sure is more than 1000 hours, ai never replaced the original batteries in 6 years (but I'm not sure how many hours I used it, I have other DMMs too).

I said: they complement each other very well. That's a particular screen about mV and Hz, other screens are different, and you can do some setup.

Some people like the Continuity/Resistance Tone, which is practical.

I'm not saying to buy a U1282A, there are cheaper and very good DMMs like Brymen 869s, but, is nice to have and work with a U1282A, the accuracy is astonishing.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 06:01:10 pm
Maybe HP (Agilent, Keysight) is good in making low power consumption and very (for decades) accurate DMMs.

http://powersupply.blogs.keysight.com/2012/06/battery-drain-analysis-of-handheld-hp.html (http://powersupply.blogs.keysight.com/2012/06/battery-drain-analysis-of-handheld-hp.html)
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 15, 2022, 06:07:21 pm
We are using a 40 ohm resistor and the meter sends up  something like: +4.00108000E+01.  There's no missing data that would get us to what we are seeing.    So far it appears random and can be reproduced without Keysight's software, drivers or interface cable.   

I changed the test program to switch between two sample rates every 10 samples to see if that has any effect.   

Personally, I blame this problem on those that voted for this meter!!  You knew dam well I wouldn't just unbox it and give it five stars!!   :-DD :-DD :-DD

Joe and Defpom videos showed that this DMM is so damn good and accurate, I really don't care about the 31MHz limitation, this is a secondary feature, just to compare, the Fluke 289 is only up to 1MHz, 1Vpp.

That Log glitch maybe could be fixed via Firmware, not a big deal since most people only use the Max/Min for a couple of seconds or minutes.

BTW, Congrats to Defpom, awesome tests, try to get a Fluke 289 to do the same tests.

The 289 is a pretty old design by now, and I'm not sure it's really the direct competition for the 1282. Maybe the 87V MAX (that always makes me think of an old Yamaha muscle-bike) would be more appropriate?

Re: Rotary switch feel comparisons, I don't have a 1282 but I do have a 1273, and though it isn't terrible, it's not as nice as a Fluke 87V or 289. I'd also agree that the 869S is a bit stiff, and mine is far from new...
The best feeling HPAK rotary switch I've used is on my Agilent U1401B, which wasn't even made by Agilent... My old HP 971A had a better feel to the switch action, though it's less comfortable to use as it's small and excessively squared off IMO. Surprising how they can get something so fundamental so wrong.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 06:18:53 pm
When measuring VAC, I like that shows big numbers for Voltage and small for Frequency.

Keysight and Fluke are brands built over decades, even today we can see very used and abused Flukes and HPs with perfect accuracy, with no worries about calibration.

But, as I said, it's nice to have and use a Keysight U1282A, but there are other high-end and cheap DMMs.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 15, 2022, 06:30:25 pm
When measuring VAC, I like that shows big numbers for Voltage and small for Frequency.

Keysight and Fluke are brands built over decades, even today we can see very used and abused Flukes and HPs with perfect accuracy, with no worries about calibration.

But, as I said, it's nice to have and use a Keysight U1282A, but there are other high-end and cheap DMMs.

Just to say that my used (and presumably abused) 1273A does have an accuracy issue on DCV and ohms ranges, which I have not yet tracked down (no visible damage, only got as far as ruling out the protection circuitry to date). So they are not indestructible by any means...
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 07:04:39 pm
So they are not indestructible by any means...[/b]

I didn't say "indestructible" or "perfect", All products could require Repair services, the difference is the Frequency and Percentage of defective products.

Suppose a company buys 10 DMMs, after 3-years, we can see how many will be inoperable, and I guess Brymen won't last like Flukes and Keysights.

I'm sorry about your problem.  The U1273AX has an interesting feature "-40 to 55 °C operating temperature", this is useful for outdoor work in Cold and Hot places, very few DMMs can operate in that range.

Fluke 87V, 289; Keysight U127XA, U128XA is "-20°C to + 55°C" and Altitude 3000m.

Brymen 869s is only "0°C to 45°C" and Altitude below 2000m!!! LOL
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 15, 2022, 07:08:27 pm
So they are not indestructible by any means...[/b]

I didn't say "indestructible" or "perfect", All products could require Repair services, the difference is the Frequency and Percentage of defective products.

Suppose a company buys 10 DMMs, after 3-years, we can see how many will be inoperable, and I guess Brymen won't last like Flukes and Keysights.

I'm sorry about your problem.  Your DMM has an interesting feature "-40 to 55 °C operating temperature", this is useful for outdoor work in Cold and Hot places, very few DMMs can operate in that range.

Fluke 87V, Fluke 289, Keysight U1282A is "-20 °C to + 55 °C".

Brymen is only "0°C to 45°C"!!! is a pussy :-DMM for internal use only LOL

It's a bigger operating temperature range than me, that's for sure!

I will get around to fixing it (I suspect one of the MUX's), it would be a shame not to after I went to the trouble of replacing the OLED display, which looks very nice btw.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 15, 2022, 07:17:40 pm
For anything under 100kHz I'm not sure why anybody would pay 3x more than a Brymen.

I was rechecking the Brymen 869s specs and seem lower compared to Fluke 289 and Keysight U1282A.  It's more comparable to Fluke 87V and Keysight U1272A:

https://static.eleshop.nl/mage/media/downloads/Brymen_867_869_manual.pdf
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 12:15:59 am
Sorry for the late reply. It's been a long day
....
Thanks for sharing these. The glitch looks similar to what I experienced before on a Keithley 2700. Other than that the drift doesn't look so bad. Definitely better than my Gossen calibrator. Did you connect the resistor directly to the banana socket?

I ran the battery life test tonight and as promised, I tried it in both DCV and resistance modes.   With the 40ohm load, I was able to lower the battery voltage until the meter turns off without any change in the measurement.  The same was true with a DCV source.    I have seen this be a problem before so didn't hurt to check.   

I have some other tests I want to run before we start the destructive testing so if there is anything else you would like me to look at, let me know.   
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 16, 2022, 12:59:32 am
I ran the battery life test tonight and as promised, I tried it in both DCV and resistance modes.   With the 40ohm load, I was able to lower the battery voltage until the meter turns off without any change in the measurement.  The same was true with a DCV source.    I have seen this be a problem before so didn't hurt to check.   

I have some other tests I want to run before we start the destructive testing so if there is anything else you would like me to look at, let me know.

The stability of this meter looks pretty good. Thanks for taking the time to do these tests. Have you figured out the reason behind the glitch?
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 16, 2022, 01:04:55 am
Battery by sure is more than 1000 hours, ai never replaced the original batteries in 6 years (but I'm not sure how many hours I used it...)

 ???

Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 16, 2022, 01:41:31 am
Sorry for the late reply. It's been a long day
....
Thanks for sharing these. The glitch looks similar to what I experienced before on a Keithley 2700. Other than that the drift doesn't look so bad. Definitely better than my Gossen calibrator. Did you connect the resistor directly to the banana socket?

I ran the battery life test tonight and as promised, I tried it in both DCV and resistance modes.   With the 40ohm load, I was able to lower the battery voltage until the meter turns off without any change in the measurement.  The same was true with a DCV source.    I have seen this be a problem before so didn't hurt to check.   

I have some other tests I want to run before we start the destructive testing so if there is anything else you would like me to look at, let me know.
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 01:48:35 am
I ran the battery life test tonight and as promised, I tried it in both DCV and resistance modes.   With the 40ohm load, I was able to lower the battery voltage until the meter turns off without any change in the measurement.  The same was true with a DCV source.    I have seen this be a problem before so didn't hurt to check.   

I have some other tests I want to run before we start the destructive testing so if there is anything else you would like me to look at, let me know.

The stability of this meter looks pretty good. Thanks for taking the time to do these tests. Have you figured out the reason behind the glitch?

Again, keeping in mind the meter was sitting out in the open on my desk with no attempt to control the temperature.   

In the following message, you can see how I am now able to reproduce the problem with ease without their software, cable or driver.   I would say the root problem is with the firmware.   Sadly, as I have said, Keysight will not open a dialog with me and I see no reason to send anymore time with this particular problem.  Just be aware of it.     
   
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg4358551/#msg4358551 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg4358551/#msg4358551)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 01:50:45 am
Sorry for the late reply. It's been a long day
....
Thanks for sharing these. The glitch looks similar to what I experienced before on a Keithley 2700. Other than that the drift doesn't look so bad. Definitely better than my Gossen calibrator. Did you connect the resistor directly to the banana socket?

I ran the battery life test tonight and as promised, I tried it in both DCV and resistance modes.   With the 40ohm load, I was able to lower the battery voltage until the meter turns off without any change in the measurement.  The same was true with a DCV source.    I have seen this be a problem before so didn't hurt to check.   

I have some other tests I want to run before we start the destructive testing so if there is anything else you would like me to look at, let me know.
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)
Thank you for that reminder.  I will use that when I make the next segment and compare it against the data I collected.   
Title: Re: Handheld meter robustness testing
Post by: Trader on August 16, 2022, 02:20:40 am
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Your tests are impressive, I wonder why did you find half of the time informed in the datasheet:

Keysight U1273A: up to 60 hours vs 33.33h
Keysight U1282A: up to 800 hours vs 377.4h

BTW, these OLED DMMs have terrible battery life.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 16, 2022, 03:15:10 am
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)

Your tests are impressive, I wonder why did you find half of the time informed in the datasheet:

Keysight U1273A: up to 60 hours vs 33.33h
Keysight U1282A: up to 800 hours vs 377.4h

BTW, these OLED DMMs have terrible battery life.
Trader, the tests we did (joe also did similar tests a few posts before mine) were a linearization of a typical battery behaviour. The simple quotient between a nominal value for the battery capacity (which may vary between brands and models) and the current consumption are more optimistic than a real battery. For example, for the UT61E the cutoff voltage of just 2,3V (which yields the 305h) is unrealistic as the meter wouldn't start at all since it would throw a beep that draws much more current than the battery would be capable of supplying.
Silent meters such as the U1282A could potentially power on, but a move to the ohms range would probably drain more than the battery could supply (0,975V per cell is borderline a cliff).

So, expect these simulations/tests to be more than one could obtain from these meters. The "up to" is fundamentally misleading if not provided with the test conditions (including the battery brand and mfg year).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 03:38:48 am
This post explains the setup.

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2081572/#msg2081572 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2081572/#msg2081572)

Interesting as you talk about the Fluke 101 compared with the U1289A.   Maybe Keysight overstated the battery life?
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 16, 2022, 03:50:53 am
Maybe Keysight overstated the battery life?

It wouldn't be the first thing they've overstated.  ::)

Also, it is mechanically quite robust (Dave went through a canyon with it)

They may be waterproof but are they robust?

This other Keysight meter didn't do too well:

https://www.youtube.com/watch?v=z9732OYPRx8 (https://www.youtube.com/watch?v=z9732OYPRx8)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 04:09:14 am
Certainly the switch was a poor choice and electrically it was not very robust.   Your Fluke 101 would run circles around it.

Odd, it looks the BM869s is reading 1.03 while the BM789 is 1.08.  Notice anything funny with that Keysight meter?   I've had that BM869s down to -40C before.   Let's see how the Keysight meter likes it because after all, it's spec'ed lower than the Brymen.    :-DD

Poor meters have to earn my respect.

***
:-DD Yes, I know -40 is the crossover.  It's also what I used to design for. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 04:46:28 am
Brymen owner's already know how their meters perform but you Keysight fanboys will have to wait.  That's a 1mV signal from my Fluke standard.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 16, 2022, 06:29:55 am
This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 16, 2022, 10:35:39 am
Brymen owner's already know how their meters perform but you Keysight fanboys will have to wait.  That's a 1mV signal from my Fluke standard.
Is this the display or the meter itself? It would be interesting to see if it comes back to life if the temperature is gradually raised back to its specified -20ºC.

This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?
Although the meter is still working under these conditions, the apparent underspec might be met if the meter is pushed towards its operational range (1kV at CAT III or CAT IV environment).
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 16, 2022, 10:38:13 am
Also, it is mechanically quite robust (Dave went through a canyon with it)

They may be waterproof but are they robust?
Dave did not only put it through waterproof tests, but many more:

https://www.eevblog.com/forum/blog/eevblog-868-keysight-u1282a-multimeter-torture-test/ (https://www.eevblog.com/forum/blog/eevblog-868-keysight-u1282a-multimeter-torture-test/)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 12:05:54 pm
This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?

Why would CEM spec their frequency counter to 100MHz when I've shown it working above 150?   Of course I can't speak for Brymen or any other company.   I did gain some respect for CEM surpassing what they state in their datasheet by a large margin and after running the BM789 down to -40C and seeing how well it tracked, they too continue to gain my respect.   

Maybe you could answer why would a viewer call Brymen owner's "pussies" then withdraw it?   Maybe you too are looking for a little respect for your expert opinions?   :-DD :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 12:20:12 pm
Brymen owner's already know how their meters perform but you Keysight fanboys will have to wait.  That's a 1mV signal from my Fluke standard.
Is this the display or the meter itself? It would be interesting to see if it comes back to life if the temperature is gradually raised back to its specified -20ºC.
I am guessing you are referring to the Keysight LCD where I blanked out the LCD.   Don't worry, the next video segment will show it all.   

Quote
Dave did not only put it through waterproof tests, but many more:
Very true and watching Dave abuse the meter's mechanically, as a EE was this is partly what started me looking at how robust they were electrically.   That and the dataless fanboys.   

I have had the function switches fail which is why I started running that 50,000 full rotation test.  This is something I would have expected Dave to do, but it takes time to setup.   In the case of that last Keysight meter though, it was all over after a few thousand cycles.  There were no more audible clicks coming from my lab as the Keysight went into stealth mode. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 16, 2022, 12:23:29 pm
This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?
Although the meter is still working under these conditions, the apparent underspec might be met if the meter is pushed towards its operational range (1kV at CAT III or CAT IV environment).

That's 100% speculation.

(and also contains an unfounded insinuation that a Keysight wouldn't do that even though it has a lower CAT rating than the Brymen)

Title: Re: Handheld meter robustness testing
Post by: Trader on August 16, 2022, 01:57:40 pm
Maybe you could answer why would a viewer call Brymen owner's "pussies" then withdraw it?   Maybe you too are looking for a little respect for your expert opinions?   :-DD :-DD

The only thing I can say is that YOU are Destroying your review with So MUCH BIAS against Keysight and in Favour of Brymen, in fact, Brymen sends free DMMs to you!

I would suggest you try to be less passionate and more impartial, I know that many tricks can be done to make up for a result, remember the "Volkswagen emissions scandal" (aka "Dieselgate", "Emissionsgate")?

I'm not saying this is a "Brymengate", but all your comments expose a hating against Keysight since the beginning, this gives a strong discredit to your review.

BTW: the Keysight U1282A specs says: "-20°C to +55°C", not -40C; and Brymen 869s datasheet says "0°C to 45°C", so I guess they never tested that, just put a conservative value, OR, there is something else...
Title: Re: Handheld meter robustness testing
Post by: Grandchuck on August 16, 2022, 02:31:18 pm
Joe is one of the most unbiased and methodical reviewers out there.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 16, 2022, 02:44:15 pm
This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?

The obvious answer is that their specs are conservative and leave some margin. I'm not aware of any tests where Brymen meters have underperformed.

OR, there is something else...

Feel free to post any evidence/findings here.

Meters in this thread have to earn their respect, nothing is given for free.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 16, 2022, 02:48:07 pm
I don't disagree, I watched several reviews and read several posts from him.

But, here in this thread, for me, it's clear he have some prejudice against Keysight, he said that they don't care about his emails, and he is making a Storm to any issue.

My opinion is that this behavior should be avoided, think about a judge taking a side during the middle of the judgment.

Would be better a partial review, and let the people decided about.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on August 16, 2022, 02:54:13 pm
Next episode:

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 02:58:51 pm
Maybe you could answer why would a viewer call Brymen owner's "pussies" then withdraw it?   Maybe you too are looking for a little respect for your expert opinions?   :-DD :-DD

The only thing I can say is that YOU are Destroying your review with So MUCH BIAS against Keysight and in Favour of Brymen, in fact, Brymen sends free DMMs to you!

I would suggest you try to be less passionate and more impartial, I know that many tricks can be done to make up for a result, remember the "Volkswagen emissions scandal" (aka "Dieselgate", "Emissionsgate")?

I'm not saying this is a "Brymengate", but all your comments expose a hating against Keysight since the beginning, this gives a strong discredit to your review.

BTW: the Keysight U1282A specs says: "-20°C to +55°C", not -40C; and Brymen 869s datasheet says "0°C to 45°C", so I guess they never tested that, just put a conservative value, OR, there is something else...

All I am doing is presenting data.  You may not like it and feel your only option is to resort to name calling.  While childish, it's fairly common.   I've said how my transient generators are not intelligent and don't care what is connected to them.  There is no bias.  The same for my other tests.     

Early on in this thread I made my hatred of Fluke clear and provided background on why.  People would still accuse me of being a fanboy of Fluke.   :-DD   If it had not been for Fungus suggesting I look at the 101, I would have never owned another Fluke.   During the testing, they have earned my respect as they continue to prove themselves.  I will gladly eat crow.  Go back and read the posts when I was looking at that Gossen Ultra.  Talk about a witch hunt (I think was what one member was calling it.). 

CEM data sheets show 100MHz for their counter, not 150MHz.  I guess they never tested it.    Keysight U1282A datasheet also shows 100MHz and they can't achieve half that.  I guess they also never tested it!   :-DD    That's fine.  As I said, I push these meters.  If you like unboxing, 5 star reviews, to feel good about your purchases, look elsewhere. 

Indeed, it's well documented that after buying my BM869s and explaining to Brymen the tests I was running, they became very interested in knowing the outcome.   They offered to repair or replace the meter if I were to damage it during the transient tests.  In the end, I repaired it.  I also bought Dave's rebranded Brymen.   That meter has yet to be damaged.    I then asked Brymen some questions about their automotive meter and because they are hard to get here in the USA, they offered to send one.  At the same time, I mentioned the testing I was doing on the switches and how I was thinking about running the BM869s.   They provided details about their in-house testing along with some video clips (which I included in my videos).  They offered to provide a second BM869s specifically to run that test.  Which I did.   Then Dave posted about selling a new Brymen meter.   Hearing that, I contacted them about testing it the prototype.  This led to testing the 789 prototype as well.   

While Brymen has proven to have an interest in seeing how their products stack up, I don't see that with other brands.   While UNI-T and anther large company contacted me about making reviews,  once I explain what I am doing, they decline.   Again, this is nothing new and all documented.   While I would have some concern about getting products through these channels,  if Gossen for example approached me about their improvements to the Ultra (now Prime), I would gladly repeat the tests.   I would do the same if UNI-T wanted to repeat the tests on an improved UT181A.   Both of those products would be worth investing the time into.     Keysight, like any other brand will earn it's place based on how they perform.

"Volkswagen emissions scandal"  We had an youngster at work who wanted to lecture me about this case.   I gave them a history lesson so they wouldn't be so ignorant the next time they approached the topic.   
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 16, 2022, 03:13:43 pm
"Volkswagen emissions scandal"  We had an youngster at work who wanted to lecture me about this case.   I gave them a history lesson so they wouldn't be so ignorant the next time they approached the topic.

Maybe it's a bit off-topic but I am quite interested to know more about this from your point of view. What is this history lesson you were talking about?
Title: Re: Handheld meter robustness testing
Post by: Trader on August 16, 2022, 03:14:15 pm
Quote from: Fungus
Meters in this thread have to [b
earn[/b] their respect, nothing is given for free.

This is an interesting situation:

First, the specs says -20C, not -40C, no reason for criticizing Keysight, in fact I didn't see a picture of -20C.

Second, some Batteries (types/brands) stop working in low temperatures. Maybe using another battery, the result could be different for both DMMs.

Third, these "issues" like 100MHz, -40C, etc are not so important, in fact majority DMMs frequency counter are up to 1 or 10MHz.

The Log glitch is small, but relevant, maybe could fixed via software. But it's so clear that could be easily removed from the dataset, as an outlier.

This threading is becoming less technical because of reviewer impartiality, hatering against Keysight, and this issue compromise the review.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 16, 2022, 03:42:27 pm
First, the specs says -20C, not -40C, no reason for criticizing Keysight, in fact I didn't see a picture of -20C.

So ... you don't actually know if it works at -20C or not?  :-//

Two of Keysights published claims for this meter (frequency and battery life) have already been shown to be false in real tests. Both were less than half the published figure.

How much faith are you still putting in their datasheet?

The Log glitch is small, but relevant, maybe could fixed via software. But it's so clear that could be easily removed from the dataset, as an outlier.

Huh? Logging is usually used to find glitches. How will you distinguish between a momentary power glitch and an "outlier"?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 03:51:54 pm
"Volkswagen emissions scandal"  We had an youngster at work who wanted to lecture me about this case.   I gave them a history lesson so they wouldn't be so ignorant the next time they approached the topic.
Maybe it's a bit off-topic but I am quite interested to know more about this from your point of view. What is this history lesson you were talking about?
  I had 20+ years in automotive before changing careers.  Much of our government's involvement is transparent and on-line.  Rather than my point of view, try Google. 

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 16, 2022, 04:11:09 pm
Huh? Logging is usually used to find glitches. How exactly will you distinguish between a momentary power glitch and an "outlier"?

I can't say why people usually log data but that fact the we have seen the Keysight U1282A  is not reliable and the glitches could cause someone to waste time trying to find the source, it's best to be aware of it. 

Not directed towards fungus, but in general if seeing meters ran outside their published specs bothers you, I suggest finding threads better suited for your interests.   Again, I typically push the meters to failure.  Most are damaged beyond repair and are recycled.   My goal is to see how electrically robust they are when ran against a standard set of conditions.   After so many years, I expect the diehards know what's what.   
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 16, 2022, 04:33:27 pm
The concerning thing for me is as Fungus has mentioned, the performance does not match the specifications in at least two areas, and the strange thing is it's in things most people couldn't care less about. Who cares if a handheld DMM can measure to 30MHz or 100MHz? I don't, it's little more than a gimmick. If I'm making a serious frequency measurement I'm using a counter and/or a scope.

I care that they chose to claim better performance than they deliver; it's out of character for a premium brand, but fits with the corporate bean counter culture that seems to have ousted the engineering culture at HPAK.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 16, 2022, 04:56:21 pm
Huh? Logging is usually used to find glitches. How will you distinguish between a momentary power glitch and an "outlier"?

You are right, I was thinking about that resistance log.
Title: Re: Handheld meter robustness testing
Post by: armandine2 on August 16, 2022, 07:19:29 pm
 . . . my feeling regarding someone taking the time, to do a proper test of a meter, is it's great - and the manufacturer surely should've done at least the same, if not much more.  :palm:

ed - I voted for the Keysight - as a potential purchaser of such an expensive piece of TE - it seemed prudent.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 17, 2022, 01:31:22 am
Brymen owner's already know how their meters perform but you Keysight fanboys will have to wait.  That's a 1mV signal from my Fluke standard.
Is this the display or the meter itself? It would be interesting to see if it comes back to life if the temperature is gradually raised back to its specified -20ºC.
I am guessing you are referring to the Keysight LCD where I blanked out the LCD.   Don't worry, the next video segment will show it all.
Indeed it is. I wasn't sure if the meter had died or the display had somehow just faded away.
   
Quote
Dave did not only put it through waterproof tests, but many more:
Very true and watching Dave abuse the meter's mechanically, as a EE was this is partly what started me looking at how robust they were electrically.   That and the dataless fanboys.

I have had the function switches fail which is why I started running that 50,000 full rotation test.  This is something I would have expected Dave to do, but it takes time to setup.   In the case of that last Keysight meter though, it was all over after a few thousand cycles.  There were no more audible clicks coming from my lab as the Keysight went into stealth mode. 
Indeed. What you showed with the smaller Keysight's rotary switch (and could potentially repeat in this one) is that a chain is only strongest on its weakest link. The U1282A might survive drops and being run over by cars, but the switch, a PTC or fuse might be its Achilles' heel. What matters for someone might be insignificant for someone else. That is why tests are important.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 17, 2022, 01:33:28 am
Passions are running high around here...

This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?
Although the meter is still working under these conditions, the apparent underspec might be met if the meter is pushed towards its operational range (1kV at CAT III or CAT IV environment).

That's 100% speculation.
That is the reason why I used the words apparent and might. They give the correct measurement of uncertainty that the subject requires, as I don't work for Brymen (nor for one of their testhouses) to be absolutely sure. 

(and also contains an unfounded insinuation that a Keysight wouldn't do that even though it has a lower CAT rating than the Brymen)
I can't make any assessment on what you read between the lines, Fungus. Give it a rest and don't assume I am a Keysight fanboy. 

This Brymen 869 has no changes, right?  Why did they put Operating Temperature "0°C to 45°C" in the datasheet?

The obvious answer is that their specs are conservative and leave some margin. I'm not aware of any tests where Brymen meters have underperformed.
So, I am the one speculating, huh?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 05:49:21 am
Sorry for the late reply. It's been a long day
....
Thanks for sharing these. The glitch looks similar to what I experienced before on a Keithley 2700. Other than that the drift doesn't look so bad. Definitely better than my Gossen calibrator. Did you connect the resistor directly to the banana socket?

I ran the battery life test tonight and as promised, I tried it in both DCV and resistance modes.   With the 40ohm load, I was able to lower the battery voltage until the meter turns off without any change in the measurement.  The same was true with a DCV source.    I have seen this be a problem before so didn't hurt to check.   

I have some other tests I want to run before we start the destructive testing so if there is anything else you would like me to look at, let me know.
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013)
Thank you for that reminder.  I will use that when I make the next segment and compare it against the data I collected.
Working on the editing tonight and took a screen shot of your data.  When I compared the nominal with what I collected, we were very close.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 06:00:59 am
Brymen owner's already know how their meters perform but you Keysight fanboys will have to wait.  That's a 1mV signal from my Fluke standard.
Is this the display or the meter itself? It would be interesting to see if it comes back to life if the temperature is gradually raised back to its specified -20ºC.
I am guessing you are referring to the Keysight LCD where I blanked out the LCD.   Don't worry, the next video segment will show it all.
Indeed it is. I wasn't sure if the meter had died or the display had somehow just faded away.
Just a quick erase with Paint.  The results were actually very surprising if you haven't looked at yours.  About 4 hours of testing boils down to 6 minutes of video.   

My plan is to run all the non-destructive tests for this next segment, then move onto the transient tests and finally finish up with the switch testing.  If there is anything left of the meter, we can open it up for any other destructive tests people may want to see.     
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 06:30:30 am
The concerning thing for me is as Fungus has mentioned, the performance does not match the specifications in at least two areas, and the strange thing is it's in things most people couldn't care less about.
...
I care that they chose to claim better performance than they deliver; it's out of character for a premium brand, but fits with the corporate bean counter culture that seems to have ousted the engineering culture at HPAK.


True, they don't actually state the data logger is glitch free or that it works at all.  So, no embellishment going on there.   Of course, there may be a level of customer expectations that they didn't consider.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 17, 2022, 11:00:33 am
The concerning thing for me is as Fungus has mentioned, the performance does not match the specifications in at least two areas, and the strange thing is it's in things most people couldn't care less about.


I think a lot of people care about battery life. It was one of the mentioned when I asked why people would buy this meter.

Keysight also seems to think it's important: It's number three on the "key features" list in the brochure (right after counts and DC accuracy) and it gets the very first paragraph in the blurb.

See page 2 of this: https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf)

Prolonged battery life and rugged
"The last thing you want is for your tools to run out of juice when you need it the most. The U1280 series
handheld DMMs lets you carry out test and measurements over a longer duration than ever before. With
up to 800 hours of battery life, you have a handheld DMM which works for a long time minus the hassle of
battery change, especially useful for frequent usage or prolong testing. Put your battery concerns behind
and fully focus on your work at hand, as it should be for maximum productivity."


(I guess they do say "up to". Maybe you can do it with fancy lithium batteries or something... ::) )
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 12:56:37 pm
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
Could you please go back and retest your MaxFunc readings?   I measured higher back light current than you show which I guess isn't too big of a surprise but I wonder what you did to get the MaxFunc up to 7.1mA? 

When I have taken this data, its always without the leads attached.  Did you have a load attached?   I just tried it with my other equipment and repeated what I see with my source meter that I normally use.  Everything repeats.  I then tried it with a short in continuity mode with the beeper full on and still could not reach 7.1mA.   It could be the two meters are just that different and maybe they tried to improve the battery life.   I just want to make sure I didn't miss something.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 17, 2022, 01:32:13 pm
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
Could you please go back and retest your MaxFunc readings?   I measured higher back light current than you show which I guess isn't too big of a surprise but I wonder what you did to get the MaxFunc up to 7.1mA? 

When I have taken this data, its always without the leads attached.  Did you have a load attached?   I just tried it with my other equipment and repeated what I see with my source meter that I normally use.  Everything repeats.  I then tried it with a short in continuity mode with the beeper full on and still could not reach 7.1mA.   It could be the two meters are just that different and maybe they tried to improve the battery life.   I just want to make sure I didn't miss something.   
Joe, I can do this later. Regarding the MaxFunc, there might be a chance I was trying with a mode other than continuity (I was fishing for the highest consumption regardless of the mode).

The capacitance mode comes to mind, but I can't be sure at the moment.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 17, 2022, 04:18:55 pm
The concerning thing for me is as Fungus has mentioned, the performance does not match the specifications in at least two areas, and the strange thing is it's in things most people couldn't care less about.


I think a lot of people care about battery life. It was one of the mentioned when I asked why people would buy this meter.

Keysight also seems to think it's important: It's number three on the "key features" list in the brochure (right after counts and DC accuracy) and it gets the very first paragraph in the blurb.

See page 2 of this: https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf (https://www.keysight.com/us/en/assets/7018-04867/data-sheets/5992-0847.pdf)

Prolonged battery life and rugged
"The last thing you want is for your tools to run out of juice when you need it the most. The U1280 series
handheld DMMs lets you carry out test and measurements over a longer duration than ever before. With
up to 800 hours of battery life, you have a handheld DMM which works for a long time minus the hassle of
battery change, especially useful for frequent usage or prolong testing. Put your battery concerns behind
and fully focus on your work at hand, as it should be for maximum productivity."


(I guess they do say "up to". Maybe you can do it with fancy lithium batteries or something... ::) )

Up to a point, I suppose. I mean, if it was 6 hours, I'd be quite displeased, but when you are talking about the difference between say, 800 and 400 hours, no, I really don't care, and I'd be quite surprised if it was a deal maker/breaker for anyone else. I have spare batteries, both at home and at work.   :-//
Title: Re: Handheld meter robustness testing
Post by: Trader on August 17, 2022, 06:57:23 pm
:-DD Yes, I know -40 is the crossover.  It's also what I used to design for.

The U1282A specs say -20C, not -40C.

Some Batteries (material/brands) stop working in low temperatures.

I wonder if removing the batteries from all DMMs and just using a power supply, how would they perform?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 10:29:08 pm
We had gone through some simplified battery life tests before and I show the numbers below including the U1282A
Could you please go back and retest your MaxFunc readings?   I measured higher back light current than you show which I guess isn't too big of a surprise but I wonder what you did to get the MaxFunc up to 7.1mA? 

When I have taken this data, its always without the leads attached.  Did you have a load attached?   I just tried it with my other equipment and repeated what I see with my source meter that I normally use.  Everything repeats.  I then tried it with a short in continuity mode with the beeper full on and still could not reach 7.1mA.   It could be the two meters are just that different and maybe they tried to improve the battery life.   I just want to make sure I didn't miss something.   
Joe, I can do this later. Regarding the MaxFunc, there might be a chance I was trying with a mode other than continuity (I was fishing for the highest consumption regardless of the mode).

The capacitance mode comes to mind, but I can't be sure at the moment.
Looks like it may have been diode check with a short to enable the beeper.  This gets me very close so I think we are all set.   
Title: Re: Handheld meter robustness testing
Post by: TheDefpom on August 17, 2022, 10:44:55 pm

With the timing, I still think it's damage control.    :-DD

I actually approached Daniel about 3 or 4 months ago about doing a multimeter review, I had to wait a while before it could be sent due to component shortages.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 11:10:00 pm

With the timing, I still think it's damage control.    :-DD

I actually approached Daniel about 3 or 4 months ago about doing a multimeter review, I had to wait a while before it could be sent due to component shortages.

I did not watch both parts and only skimmed the one.  Did you run temperature, battery life, data logging on the meter?   Any other odd tests that gave you trouble that you would like to see if I can replicate?   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 17, 2022, 11:17:03 pm
Will we see history once again repeat itself??    :-DD   I have changed the brand name for your viewing pleasure. 
 

When I first listened to the video you came across as strongly anti Keysight so that appears to make you biased against the company straight away. Every multimeter has to be treated independently so it does not depend on the series or company it is from. You have said this yourself! There is a danger that you will stereotype a company because it does not at first live up to your own standards. "Saving your skin" is just saying that viewers will treat you with more respect and not pass you off as an anti Keysight tester.

I don't understand the point of testing these meters beyond their specifications. It says right on the front of the Keysight: "1000v" with CAT IV; why go beyond this?

These test are irrelevant over what is rated, is like you smash a car at 2 mach and say "ehh car not good, unsafe, bla bla" whats the point of using a meter over the rated point???

Why did you treat the Keysight unfairly?
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 17, 2022, 11:53:14 pm
I don't understand the point of testing these meters beyond their specifications. It says right on the front of the Keysight: "1000v" with CAT IV; why go beyond this?

These test are irrelevant over what is rated, is like you smash a car at 2 mach and say "ehh car not good, unsafe, bla bla" whats the point of using a meter over the rated point???

Why did you treat the Keysight unfairly?

I read this as a challenge that you need to up your transient tester to actually be able to output 6000A at 12KV with a 2Ohm source impedence.  :box:

I mean the last thing you want to do is treat the Keysight unfairly and not to it's rated spec.  :-DD
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 18, 2022, 12:16:51 am
Some Batteries (material/brands) stop working in low temperatures.

So you keep saying...

Look closer though: The reason there's no display on the Keysight at -40C is that joe blanked it out using Windows Paint to keep us in suspense.

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1568489;image)

All the "-40C" image shows is that the Brymens are still working, it doesn't say anything about the Keysight.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 02:07:19 am
 :-DD

I would hate the Keysight fanboys to think their meter turned off because of crap batteries so here's a better view of the U1282A...   

I don't understand the point of testing these meters beyond their specifications. It says right on the front of the Keysight: "1000v" with CAT IV; why go beyond this?

These test are irrelevant over what is rated, is like you smash a car at 2 mach and say "ehh car not good, unsafe, bla bla" whats the point of using a meter over the rated point???

Why did you treat the Keysight unfairly?

I read this as a challenge that you need to up your transient tester to actually be able to output 6000A at 12KV with a 2Ohm source impedence.  :box:

I mean the last thing you want to do is treat the Keysight unfairly and not to it's rated spec.  :-DD

I don't think Fungus's poor little Fluke 101 was spec'ed to handle that.   Funny that meter has never been damaged and I don't think I have had it apart.  Then to have another member step up and repeat that 12kV test just to see if I was BSing, using an actual IEC generator from their work place was a pleasure to watch.   Now that's how you review a meter!!  :-DD 

I have a few more tests I want to run and should have the next segment up this weekend.   
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 02:19:53 am
Look closer though: The reason there's no display on the Keysight at -40C is that joe blanked it out using Windows Paint to keep us in suspense.
All the "-40C" image shows is that the Brymens are still working, it doesn't say anything about the Keysight.

Yes, it's hidden. But in the previous post he said:

"Odd, it looks the BM869s is reading 1.03 while the BM789 is 1.08.  Notice anything funny with that Keysight meter?"

And posted an image that seems like "1.451 mV".

As I said, maybe the batteries were weak because of the low temperature, best to use a power supply for all DMMs.

https://www.upsbatterycenter.com/blog/batteries-in-cold/ (https://www.upsbatterycenter.com/blog/batteries-in-cold/)
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 18, 2022, 02:21:37 am
I don't think Fungus's poor little Fluke 101 was spec'ed to handle that.   Funny that meter has never been damaged and I don't think I have had it apart.

I really like the elegant simplicity of the 101. It's a neat little meter that seems to be far better than it's price would imply!

  Then to have another member step up and repeat that 12kV test just to see if I was BSing, using an actual IEC generator from their work place was a pleasure to watch.   Now that's how you review a meter!!  :-DD 

You don't happen to have a link to that video do you? I'm very interested in watching!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 02:42:57 am
You don't happen to have a link to that video do you? I'm very interested in watching!

Go to the first page where I created a TOC to help members navigate this thread.  Then find:   "Member Meter Junkie runs a second Fluke 101 on their IEC combo generator at 12KV" 

He mentions it was suggested it should survive 17.   I ran that Fluke 107 to I think 15 before it finally gave in.  Even then it was hardly a scratch.   Think this Keysight will handle that?   :-DD   :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 02:55:01 am
Two of us have measured the dropout voltage and I have provided some data how the meter is stable until it shuts down.   Of course I welcome anyone to step up and repeat any tests I show.   

We need Fungus's Canadian friend to join.  Now there was a Keysight fanboy.  He even made a rebuttal video proving the Keysight's switch would not fail after 10's of thousands of cycles.   :-DD :-DD   I don't recommend anyone going to hunt that one down.  A half hour of expert opinion.   :-DD 
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 18, 2022, 03:04:32 am
...poor little Fluke 101.   Funny that meter has never been damaged and I don't think I have had it apart.

I've had mine apart. It has some big, chunky components inside.

(https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/?action=dlattach;attach=77867;image)

Not bad for a $45 meter.

(Image from this thread: https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/ (https://www.eevblog.com/forum/testgear/fluke-101-multimeter-teardown/) )

Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 18, 2022, 04:31:53 am
You don't happen to have a link to that video do you? I'm very interested in watching!

Go to the first page where I created a TOC to help members navigate this thread.  Then find:   "Member Meter Junkie runs a second Fluke 101 on their IEC combo generator at 12KV" 

He mentions it was suggested it should survive 17.   I ran that Fluke 107 to I think 15 before it finally gave in.  Even then it was hardly a scratch.   Think this Keysight will handle that?   :-DD   :-DD

Found it but it looks like access to the video has been limited. O well, it sounds like it was pretty boring  :-DD

I hope the keysight survives. If only because I want to believe that they live up to their heritage!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 11:15:03 am
I've had mine apart. It has some big, chunky components inside.
...
Not bad for a $45 meter.
...
They just look big and chunky because the meter is so small this it fits in your shirt pocket.   

Think Adam Savage watched it unfold and decided to buy it?  Now that would be funny!
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 11:44:33 am
Found it but it looks like access to the video has been limited. O well, it sounds like it was pretty boring  :-DD

I hope the keysight survives. If only because I want to believe that they live up to their heritage!
That's too bad they set it to private.  The did post a few comments close to that link, or you could search the name in this thread to find out more about it.  I believe this was photo they sent of their generator that was used to test the 101.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 11:56:20 am
Here's a classic comment.   You loose some context once they edit their posts but you get the idea.. 
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 03:07:30 pm
:-DD
I would hate the Keysight fanboys to think their meter turned off because of crap batteries so here's a better view of the U1282A...   

Is easy to see when someone is totally biased.

You can't ask anything, or you will be a "fanboy", and all the answers are to criticize the questioner and disrespect the feedback.

But this is the standard behavior in this forum, nothing new here.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on August 18, 2022, 04:06:54 pm
:-DD
I would hate the Keysight fanboys to think their meter turned off because of crap batteries so here's a better view of the U1282A...   

Is easy to see when someone is totally biased.

You can't ask anything, or you will be a "fanboy", and all the answers are to criticize the questioner and disrespect the feedback.

But this is the standard behavior in this forum, nothing new here.

You are fanboy because you behave like one...
Just look at so many of your statements...
What is your point here? Poor little Fluke and Keysight don't need you protect their valor...

Joe is having his fun, with his own money and on his own time..
You either watch or not, agree or not...

While I think some of his testing being is not always directly useful, except for entertrainment, one thing I do value him for is irreverence and following facts where they take him. And he honestly documents data as it is, good and bad...
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 04:37:54 pm
While I think some of his testing being is not always directly useful, except for entertrainment, one thing I do value him for is irreverence and following facts where they take him. And he honestly documents data as it is, good and bad...

At least you agree how useless is to use a "crappy box" with a lot of uncalibrated "references" that even an HB DMM will do very good, put it in a refrigerator below the specs without confirming batteries specs, and the best part, do 50K knob rotations, LOL  :-DD.

I'm not a fanboy, YOU and he are hatters of people that express divergent opinions.

Actually, these are the same people that prefer to Destroy a DMM by dropping it from a dam, just for "entertainment".

MY (understand this word: "MY", ok?) opinion is that the TheDefpom 2-videos review was much more useful, to verify if all the specs are very accurate (much better than that crappy box), and did you read that "With the timing, I still think it's damage control", a big shame...  :palm:

-40 degrees, 50K rotations, 100ft dropping, 14K transients, etc...  seems like an ElectroBoom review, just for fun. Almost zero probability of this use. (I won't ever use it above 1000V (or even 400V), and if this happens will be 15K, 30K, or 100K? doesn't matter, this is Very Far from the Max Specs).

The LOG issue was a useful discovery, interesting nobody realized that in 7 years (people were more concerned about dropping it from a waterfall), anyway, I hope KS checks/fix that.

Remember, this is "MY" option, and I don't care what you think about other people's opinions, if you don't agree, you are free to express YOUR OWN opinion since don't criticize other people's opinions.

But, since I know very well the Total Lack of Respect from the majority of people here... no hope.
Title: Re: Handheld meter robustness testing
Post by: tautech on August 18, 2022, 04:47:37 pm

But, since I know very well the Total Lack of Respect from the majority of people here... no hope.
Can I say in reference to this BS, respect is earned not given as a right.

Maybe as a newbie here you are yet to learn this ?  :-//
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 05:04:50 pm
Maybe as a newbie here you are yet to learn this ?  :-//

"Can I say in reference to this BS, respect is earned not given as a right."
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 18, 2022, 05:14:38 pm
-40 degrees, 50K rotations, 100ft dropping, 14K transients, etc...  seems like an ElectroBoom review, just for fun. Almost zero probability of this use. (I won't ever use it above 1000V (or even 400V), and if this happens will be 15K, 30K, or 100K? doesn't matter, this is Very Far from the Max Specs).

I wasn't aware that Joe was testing the meter for your personal gratification.  :-//

I'm not a fanboy, YOU and he are hatters of people that express divergent opinions.

Your "opinion" was: "U1282A 4-batteries last more than 1000 hours".

Your evidence for that? "I never replaced the original batteries in 6 years (but I'm not sure how many hours I used it)"

Surely it's better to measure the meter's current consumption and crunch the numbers than to just have an opinion on the matter.

What would happen of we built bridges and designed aircraft based on opinion?
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on August 18, 2022, 05:22:50 pm
While I think some of his testing being is not always directly useful, except for entertrainment, one thing I do value him for is irreverence and following facts where they take him. And he honestly documents data as it is, good and bad...

At least you agree how useless is to use a "crappy box" with a lot of uncalibrated "references" that even an HB DMM will do very good, put it in a refrigerator below the specs without confirming batteries specs, and the best part, do 50K knob rotations, LOL  :-DD.

I'm not a fanboy, YOU and he are hatters of people that express divergent opinions.

Actually, these are the same people that prefer to Destroy a DMM by dropping it from a dam, just for "entertainment".

MY (understand this word: "MY", ok?) opinion is that the TheDefpom 2-videos review was much more useful, to verify if all the specs are very accurate (much better than that crappy box), and did you read that "With the timing, I still think it's damage control", a big shame...  :palm:

-40 degrees, 50K rotations, 100ft dropping, 14K transients, etc...  seems like an ElectroBoom review, just for fun. Almost zero probability of this use. (I won't ever use it above 1000V (or even 400V), and if this happens will be 15K, 30K, or 100K? doesn't matter, this is Very Far from the Max Specs).

The LOG issue was a useful discovery, interesting nobody realized that in 7 years (people were more concerned about dropping it from a waterfall), anyway, I hope KS checks/fix that.

Remember, this is "MY" option, and I don't care what you think about other people's opinions, if you don't agree, you are free to express YOUR OWN opinion since don't criticize other people's opinions.

But, since I know very well the Total Lack of Respect from the majority of people here... no hope.

First and foremost, I don't agree anything with you..
It is you who is rude and abrasive.

Defpom videos where he checks "accuracy" of reading have (to me) same merit as Joes "plastic"box, unless his calibrators are kept in current calibration with traceable calibration facility. They are both homemade quick sanity check of basic functionality. Joe is clear and open about that. It is you who didn't listen, chose to ignore, or deliberately lie about his intentions.

I don't think long videos where people check calibration of meters are useful. It is a waste of time, and a table made in accordance manufacturers performance verification test  is both more accurate and concise way of relaying that info. Again, only if reviewer has both calibrated equipment and skills to perform procedure correctly in a first place..

When reviewing multimeter, I like to see any operational quirks (things that are made counterintuitive or in weird way), things that are not mentioned in datasheets, obvious failings and deficiencies that are either not mentioned or contrary to datasheets....

And to quote one our member here:

"
Remember, this is "MY" option, and I don't care what you think about other people's opinions, if you don't agree, you are free to express YOUR OWN opinion since don't criticize other people's opinions.

But, since I know very well the Total Lack of Respect from the majority of people here... no hope.
"
Let me rephrase this confused statement into something more lucid:

You are free to express your opinions. Please don't attack people that don't agree with you. Accept that in same way as you have freedom to express anything you like, you shouldn't be rude to people, and in addition to that , these other people have freedom to call bullshit, laugh if you say something stupid or similar.
If you said something stupid or malicious, they have freedom to call you out on it. It doesn't mean they have right to insult you explicitly.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 05:37:35 pm
I wasn't aware that Joe was testing the meter for your personal gratification.  :-//

Me neither, what's your point?  Can't I be free to like or dislike? Or have free speech for feedback?

Your "opinion" was: "U1282A 4-batteries last more than 1000 hours".

The manual says "800 hours typical based on new alkaline batteries for DC Voltage measurement".

I was very clear, this is an Opinion Based on Empirical Observation! I never demanded fixing that "battery life table"!!!

Maybe the new firmware could consume more power, or the settings, readings per second, etc; but I'm sure that I use it Much More than 377.4h hours (informed on that table) and the batteries still like full, even after being installed 6-years ago!!!
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 18, 2022, 05:59:48 pm
I wasn't aware that Joe was testing the meter for your personal gratification.  :-//

Me neither, what's your point?  Can't I be free to like or dislike? Or have free speech for feedback?

Your "opinion" was: "U1282A 4-batteries last more than 1000 hours".

The manual says "800 hours typical based on new alkaline batteries for DC Voltage measurement".

I was very clear, this is an Opinion Based on Empirical Observation! I never demanded fixing that "battery life table"!!!

Maybe the new firmware could consume more power, or the settings, readings per second, etc; but I'm sure that I use it Much More than 377.4h hours (informed on that table) and the batteries still like full, even after being installed 6-years ago!!!

DCV measurement puts the least demand on the batteries; the AC TRMS converter is inactive, there is no current being used to measure resistance or diode junction drop, and no ramp is generated to charge a capacitor. It verges on the disingenuous to categorise a use profile that is exclusively DCV as "typical".

Unless you have recorded your "observations" ie made written logs of the powered on time of your meter on this battery set, I'm afraid you can't describe it as "empirical". Human recollection is notoriously unreliable, which is why we write things down.

I would also point out that leaving alkaline batteries unchanged for 6 years is a recipe for disaster; you are gambling the life of your meter on them not leaking, despite a great deal of genuinely empirical evidence pointing to the high probability of this happening.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 06:06:47 pm
First and foremost, I don't agree anything with you..

Same, I totally agree.

Defpom videos where he checks "accuracy" of reading have (to me) same merit as Joes "plastic"box, unless his calibrators are kept in current calibration with traceable calibration facility.

I disagree, you can use a "crappy box" but at least provide the Precision Values to All References (measured in calibrated equipment).

But watching a person saying: "that's fine", "looks good", "not a problem", for measures 10% far from the (supposed) reference value!!! This is insane.

IF the TheDefpom equipment wasn't calibrated, SO, it's "un-calibrate" to perfectly bang on the Same Values on the DMM All the time, for All measurements!!! So MY opinion is that both are perfectly calibrated.

You are free to express your opinions. Please don't attack people that don't agree with you. Accept that in same way as you have freedom to express anything you like, you shouldn't be rude to people

I'm 100% Sure that I never offended or even disrespect other people here. I disagree with "respect is earned not given as a right", for me Everyone Must Be Respected.

and in addition to that , these other people have freedom to call bullshit, laugh if you say something stupid or similar.
If you said something stupid or malicious, they have freedom to call you out on it. It doesn't mean they have right to insult you explicitly.

Hum... I guess I understand, is like: "no personal attacks, but just bullying, moral offenses, and implicitly insults", right? Thanks for clarifying. :-DD

Ok, but I still think that you can disagree and argue about an opinion, but never criticize a person for giving feedback, doesn't matter if this person is a "newbie".
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 06:15:52 pm
DCV measurement puts the least demand on the batteries; the AC TRMS converter is inactive, there is no current being used to measure resistance or diode junction drop, and no ramp is generated to charge a capacitor. It verges on the disingenuous to categorise a use profile that is exclusively DCV as "typical".

I totally agree with all your points.  At least they said that on the manual, MAYBE all other brands use the same procedure to measure the battery life, in this case, all of them had biased results.

"Human recollection is notoriously unreliable", agree, but I know that I spend a lot of time in the lab, so, still empirical for me; just 1-hour per day, 5-days a week, will be easily 250 hours per year.

"alkaline batteries unchanged for 6 years is a recipe for disaster", yes, I'll check that. Thank you for the remind me of that.
Title: Re: Handheld meter robustness testing
Post by: 2N3055 on August 18, 2022, 07:12:16 pm

Everyone must be given benefit of the doubt. Respect is earned. You claim you respect everybody but  many of your posts here are quite the opposite of that.

As for Defpom's or any other equipment, calibration is science. Your opinion of the meaning of the word means absolutely nothing. That word is already taken and defined to death. You can't have it, sorry.
You can have 10 voltmeters all showing precisely 10.0000V and all of them wrongly adjusted to same wrong 9.9V calibrator. If proper procedures are not followed it is not calibration.
It seems you didn't read all the way through the rest of that statement where I explained.

Hum... I guess I understand, is like: "no personal attacks, but just bullying, moral offenses, and implicitly insults", right? Thanks for clarifying. :-DD
:-//
Title: Re: Handheld meter robustness testing
Post by: Trader on August 18, 2022, 07:39:43 pm
Everyone must be given benefit of the doubt. Respect is earned. You claim you respect everybody but  many of your posts here are quite the opposite of that.

I disagree, show me and I'll ask sorry and revise it, if I offended someone.

You can have 10 voltmeters all showing precisely 10.0000V and all of them wrongly adjusted to same wrong 9.9V calibrator. If proper procedures are not followed it is not calibration.

You know very well that the Voltage Reference used by Dave, Defpom (and others) Aren't From the SAME Calibrator.

What's the probability of testing Other New DMMs, the results Match perfectly (almost all the time), just by a chance, or because both instruments are perfectly calibrated???

I don't have a calibrator, nor send my instruments to calibration, I just confirm that all DMMs, from Different Brands, still match each other.

I'm not saying that the "box" must be a Laboratory Grade precision, but at least, the minimum (to "gain respect") is to inform the 4+ decimal-digit precision value for all the reference voltages, resistances, capacitances, etc. Not only saying: "that's fine", "looks good", "not a problem".

But this is MY opinion and MY feedback, if you don't agree or care about that, I respect it, no problem for me; some people will test DMMs just by measuring the outlet, seeing 120V (or 240V), and say "that's perfect". :-DD

Please, if you want to continue insisting on this topic, just let me know the Precise Values of the References used on that box, and I'll compare them with what I'm seeing and not listening to.
Title: Re: Handheld meter robustness testing
Post by: armandine2 on August 18, 2022, 09:03:25 pm
re subjective opinion (on topic)

 I might be in a small minority here, but Keysight's rotary switch (on my U1242C) feels fine to me. And although I like Gossen, Fluke, and AVO well enough I find on the Keysight you're less likely to overshoot when turning it to each position. :-+

 
Title: Re: Handheld meter robustness testing
Post by: tautech on August 18, 2022, 10:16:20 pm
Will we see history once again repeat itself??    :-DD   I have changed the brand name for your viewing pleasure. 
 

When I first listened to the video you came across as strongly anti Keysight so that appears to make you biased against the company straight away. Every multimeter has to be treated independently so it does not depend on the series or company it is from. You have said this yourself! There is a danger that you will stereotype a company because it does not at first live up to your own standards. "Saving your skin" is just saying that viewers will treat you with more respect and not pass you off as an anti Keysight tester.

I don't understand the point of testing these meters beyond their specifications. It says right on the front of the Keysight: "1000v" with CAT IV; why go beyond this?

These test are irrelevant over what is rated, is like you smash a car at 2 mach and say "ehh car not good, unsafe, bla bla" whats the point of using a meter over the rated point???

Why did you treat the Keysight unfairly?
Have you never used a tool beyond what it's rated to do knowing you are putting it at risk ?

TBH we all have and I see no issue with Defpom testing/investigating if an instrument can be used beyond any of its ratings for the benefit both his and our knowledge.
There are times when we might only have a particular tool available so to know it can handle work beyond its ratings as member bd139 discovered his little Bymen BM22s could do when he needed to set the EHT on a CRO.

Shocking abuse of a DMM I know but after some trouble to find it I'll leave this here:

(https://i.imgur.com/44r6SGp.jpg)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 11:34:19 pm
You people have been busy..  :-DD


Will we see history once again repeat itself??    :-DD   I have changed the brand name for your viewing pleasure. 
 

When I first listened to the video you came across as strongly anti Keysight so that appears to make you biased against the company straight away. Every multimeter has to be treated independently so it does not depend on the series or company it is from. You have said this yourself! There is a danger that you will stereotype a company because it does not at first live up to your own standards. "Saving your skin" is just saying that viewers will treat you with more respect and not pass you off as an anti Keysight tester.

I don't understand the point of testing these meters beyond their specifications. It says right on the front of the Keysight: "1000v" with CAT IV; why go beyond this?

These test are irrelevant over what is rated, is like you smash a car at 2 mach and say "ehh car not good, unsafe, bla bla" whats the point of using a meter over the rated point???

Why did you treat the Keysight unfairly?
Have you never used a tool beyond what it's rated to do knowing you are putting it at risk ?

TBH we all have and I see no issue with Defpom testing/investigating if an instrument can be used beyond any of its ratings for the benefit both his and our knowledge.
There are times when we might only have a particular tool available so to know it can handle work beyond its ratings as member bd139 discovered his little Bymen BM22s could do when he needed to set the EHT on a CRO.

Shocking abuse of a DMM I know but after some trouble to find it I'll leave this here:

It seems like you felt this was somehow directed toward Defpom after their videos were posted.   I actually only skimmed their first video just to get some idea if they had done anything beyond the basic unboxing.     Actually all of these comments were towards me.   Just a bit of history. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 18, 2022, 11:59:57 pm
Defpom videos where he checks "accuracy" of reading have (to me) same merit as Joes "plastic"box, unless his calibrators are kept in current calibration with traceable calibration facility. They are both homemade quick sanity check of basic functionality. Joe is clear and open about that. It is you who didn't listen, chose to ignore, or deliberately lie about his intentions.

Certainly true that I use that box to make sure the meters are functional.  As I have said, I assume the meters come from the factory meeting their specified accuracy and so it's nothing I have ever considered.   I am sure anyone who has watched knows I run through a basic check between each test to see if the meter has started to fail.  Sanity check is a very good way to describe it.    While there are some decent parts inside that box,  I doubt there are very many educated people that would compare it with an actual reference.   I keep a couple of cheap standards at work that are not in cal.  Maybe $2000 for one resistor?  Something like that.  The box has maybe a $300 in parts?  I would need to total it up but I'm sure any engineer is going to know this box is nothing to do with calibrating a meter.   Well... that's not true as Dave has said that anyone who calls themselves an engineer is one.    :-DD   

I can't speak for Defpom. If they are trying to show a product meets the manufactures specs, I assume their equipment is current with cal. and they would have all the papers and records for it.   Nothing I show is NIST traceable nor was that ever the intention.   

Anyway, good post.  Thanks for trying to clear things up.   I know we have a group made up of people from all different background and education levels.  It spans from the electrician who has no idea that anything is faster than 400Hz, to the beginner electronics wizard who has no idea what ESD is, to the old fart who has spent a life time in design and still doesn't know jack (that's me).   

****
Just to add, because it always comes up.  Nothing I show has anything to do with safety.   The transients I will be applying are very low energy and have nothing to do with the IEC standards outside of my basing the open circuit voltage waveform on them.   And of course, because I see I still have some people who post "First" in the comments section, I assume a few children still hang around to watch the sparks fly.   For them, I want to state that I am not connecting the meters to a large capacitor bank and just because I may show the same meter you have surviving to 12kV, that doesn't suggest that it will survive when you hook it to mom and dads old MOT that you salvaged.   :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 19, 2022, 12:15:50 am
Joe is having his fun, with his own money and on his own time..
You either watch or not, agree or not...

While I think some of his testing being is not always directly useful, except for entertrainment, one thing I do value him for is irreverence and following facts where they take him. And he honestly documents data as it is, good and bad...

Yes, this testing has purely been out of my own interest or I would never have started it.  And certainly anyone who has watched knows I have a bit of fun with some of the lower end products.   As you said, my time, my money, my test standards ....  Everything is documented enough to where anyone could replicate it if they wanted it.  Of course, that doesn't suggest I am telling the kiddies how to construct potentially lethal transient generators but as we have seen, anyone in the business of running these kinds of tests could certainly repeat them.    Not being paid or sponsored,  I run the products I want to see the way I want to see them ran.  Viewers are along for the ride.  Once in a while you even get to pick what we look at.    Sadly, we now have this entitlement culture.  I can only imagine if I were allowing people to donate how bad it would be having to deal with them.  "I gave you a dollar last year and I demand you tell me how to fix my meter!"  Sorry, I'm not interested.    :-DD

***
SP
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 19, 2022, 01:47:24 am
re subjective opinion (on topic)
 I might be in a small minority here, but Keysight's rotary switch (on my U1242C) feels fine to me. And although I like Gossen, Fluke, and AVO well enough I find on the Keysight you're less likely to overshoot when turning it to each position. :-+
My subjective ranking is the following:
1. The absolute kings: Fluke 87V and 179
2. Fluke 101, Richmeters RM113D, Brymen BM251 (Greenlee DM200A), UT61E, Sanwa PM300
3. Keysight U1273A, U1282A, Brymen BM857, BSide ZT-Y, AstroAI M6KOR
3. Fluke 189 and 27/FM (my units were bought used, so they might have already been worn from prior use), Keysight U1233A
4. Manual ranging meters in general (the short stops are easy to get wrong)

(there may be others that I forgot)
Title: Re: Handheld meter robustness testing
Post by: Trader on August 19, 2022, 05:41:46 am
1. The absolute kings: Fluke 87V and 179

LOL, just try a Gossen  ;)
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 19, 2022, 11:37:19 am
1. The absolute kings: Fluke 87V and 179

LOL, just try a Gossen  ;)
Hehehe... They are too rich for me. I wasn't as lucky as you to get one on the cheap.  :clap:
Title: Re: Handheld meter robustness testing
Post by: tautech on August 19, 2022, 08:52:57 pm
Anyone notice a new Brymen clamp meter, the BM037 that Dave apparently will market ?

We think you should put it through its paces Joe.  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 19, 2022, 09:34:02 pm
Anyone notice a new Brymen clamp meter, the BM037 that Dave apparently will market ?

We think you should put it through its paces Joe.  :popcorn:

We?  You and Dave? 

Searching you will find it mentioned in 2020 so it's not a new product:
https://www.eevblog.com/forum/testgear/clamp-meter-safe-reliable-and-under- (https://www.eevblog.com/forum/testgear/clamp-meter-safe-reliable-and-under-)$200/
More info is here:
https://brymen.eu/shop/bm037/ (https://brymen.eu/shop/bm037/)
https://brymen.eu/wp-content/uploads/biall/102194/102194.INSTRUKCJA_EN..2019-02-26.1.pdf (https://brymen.eu/wp-content/uploads/biall/102194/102194.INSTRUKCJA_EN..2019-02-26.1.pdf)

I have never transient tested a clamp meter.  Not being an electrician, it's not something I would have much use for.   I suspect the lack of interest suggests other hobbyist also have little interest in them.  For automotive, I normally need something much more sensitive to detect high leakage currents.  On the bench, I would typically want something with much higher BW.  I like that old 1960's Tektronix P6042.  I was able to improve the UT210E's bandwidth by designing a new front end for it.  Sadly the typical UNI-T quality insures a short life as I have seen several of these now where the switches have failed after a few years. 

Guessing if Dave plans to sell it, he will make a review.  You may want to suggest tests for him to run. 
Title: Re: Handheld meter robustness testing
Post by: tautech on August 19, 2022, 09:53:37 pm
Anyone notice a new Brymen clamp meter, the BM037 that Dave apparently will market ?

We think you should put it through its paces Joe.  :popcorn:

We?  You and Dave? 
:-DD
With the fun you had with 121 I'd have thought you'd be 1st in the cue to check it out.  >:D

Quote
Searching you will find it mentioned in 2020 so it's not a new product:
https://www.eevblog.com/forum/testgear/clamp-meter-safe-reliable-and-under- (https://www.eevblog.com/forum/testgear/clamp-meter-safe-reliable-and-under-)$200/
More info is here:
https://brymen.eu/shop/bm037/ (https://brymen.eu/shop/bm037/)
https://brymen.eu/wp-content/uploads/biall/102194/102194.INSTRUKCJA_EN..2019-02-26.1.pdf (https://brymen.eu/wp-content/uploads/biall/102194/102194.INSTRUKCJA_EN..2019-02-26.1.pdf)

I have never transient tested a clamp meter.  Not being an electrician, it's not something I would have much use for.   I suspect the lack of interest suggests other hobbyist also have little interest in them.  For automotive, I normally need something much more sensitive to detect high leakage currents.  On the bench, I would typically want something with much higher BW.  I like that old 1960's Tektronix P6042. 
Yes, wonderful bits of kit these old current probes and have had a P6021 for some years and added the 120MHz P6022 to my kit a year or 2 back.

Quote
Guessing if Dave plans to sell it, he will make a review.  You may want to suggest tests for him to run.
:-DD
And put the fox in charge of the hen house, not bloody likely !


Anyways, just stumbled on it yesterday on YT:
https://www.youtube.com/watch?v=9fVIm9qEXEg&t=776s (https://www.youtube.com/watch?v=9fVIm9qEXEg&t=776s)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 19, 2022, 10:43:11 pm
I liked that 121GW because there was a lot of hype about Dave's involvement and it being a custom meter from the ground up.  Having features we don't typically see in a handheld meter.   You may have noticed a shift towards meters I 1) feel have a chance of actually doing well against my tests  2)  something that the hobbyist would want

I did go back and look at that little pocket Brymen I had left outside and beat the crap out of.  Mine over ranges at 600V.   I've had that cheap UNI-T UT90A up that high.  After damaging it so many time, it seems to breakdown around 1.5k now (see attached).  This meter has such poor creepage, the PCB acts as a spark gap right across the main feed, saving the meter.   It's one of the few UNI-T products I have looked at that can survive the grill starter because of this built-in spark gap.   Of course, that's all fine at the low energy I would normally experiment at but I show the problem when you have something like this happen with a little higher energy.   

https://youtu.be/aRuI_q_K5RY?t=410


My P6042 was a trash pick in VERY poor condition.  It took a few weeks to repair it.  Sorting bags of transistors looking for matched sets.   I was able to get the bandwidth up to about 100MHz with it.  Impressive for the age of the thing.   It belongs in a museum like much of my equipment.   One day I will open up my home lab to the public and charge admission.   :-DD

Quote
:-DD
And put the fox in charge of the hen house, not bloody likely !

The Brymen products I have looked at appear very robust when compared with other brands.   We will see how this second Keysight performs but based on the first, I don't have a lot of confidence.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 19, 2022, 10:52:22 pm
I think I once caught one of Dave's live streams maybe for the 121.  I never see any notices about them.     I'm skipping around it now.  Is there something specific you would like me to watch or just in general?   
Title: Re: Handheld meter robustness testing
Post by: tautech on August 19, 2022, 11:00:46 pm
I did go back and look at that little pocket Brymen I had left outside and beat the crap out of.  Mine over ranges at 600V.

Hmmm, is it a different model to that bd139 has ?
He said his started crackling at 2kV but that was with a low energy CRO EHT supply.
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg4367380/#msg4367380 (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg4367380/#msg4367380)

Quote
My P6042 was a trash pick in VERY poor condition.  It took a few weeks to repair it.  Sorting bags of transistors looking for matched sets.   I was able to get the bandwidth up to about 100MHz with it.  Impressive for the age of the thing.
They certainly are however I only have the 60 & 120 MHz passive AC current probes with their BNC terminations and also picked up a Type 134 amplifier for them....just to have really as the passive terminations are far more convenient.

I think I once caught one of Dave's live streams maybe for the 121.  I never see any notices about them.     I'm skipping around it now.  Is there something specific you would like me to watch or just in general?   
;)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 20, 2022, 12:33:36 am
Thanks for the link.  Didn't realize that was recent.  They could try placing it across a MOT if they wanted to see if the meter would do more than crackle.   :-DD     

I have the BM27. 

I really don't have any high voltage supplies that put out any kind of current.  Nothing close to what PhotonicInductions channel shows.   My transient generators have a lot of safety features designed into them now and are relatively low risk to use.   The half cycle generator will not run without the small high voltage generator.  I short the high voltage outputs with a chicken stick before handling anything and wear hand condoms if I am doing anything too risky.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 20, 2022, 01:50:53 am
Watching Dave's live feed.  Starts out talking about the video feed setup.  I didn't see anything of interest during this.   You may want to skip ahead. 

About 17 minutes in.  He's talking about UNI-T and margins.   That mA res is hard to beat for automotive and I don't really need absolute accuracy.  Plus they give it away.  I would pay them double for a higher quality version of it.    22:47, UNI-T mentioned again..  Surprised no one is jumping in.     25:30 in, looking it up.   Dang, $70 now.  I thought  we were getting these for $30.

Interesting comment about the UNI-Ts display being sideways.  I like it that way.   The are talking about leakage now and accuracy.  IMO, I don't normally need it. 

29:00 talking about UNI-T 61 now.   Of course we have the Fluke 87.

30:00 discovers UT210B.  Talks about wanting lower current version for electronics.  Straw pole, pretty much everyone wants the lower current range.

35: starting to ask about using a standard DMM with shunt.   

Wanky low...  :-DD  P6042 lowest range is 1mA.   Looks like there's one on eBay for $600 yankee dollars.  Maybe someone will want it.   

https://www.ebay.com/itm/325309029169?epid=1400242944&hash=item4bbdeddb31:g:qjAAAOSw-GNi~did&amdata=enc%3AAQAHAAAAoDongduZ9OKRFo20SQM3ytETKrD8C%2F%2By7T3I3ORHH4jd9vtjWk7TNPYq%2BZ4yj7BubEglOpFhqXCcYRd8dy%2FKy301iOxBnj4duOA%2B4T5NkLsyPypXadQrDvXxBP%2B2%2F%2F7DvmGn9UtsU9M%2BUd2AirSnK32Do6wWwEQmU3HBAuAbzqSynAnp5fRmmzF3TWZYyN%2BdEXM%2B2v1%2FlYS7gfcjpZ46OSo%3D%7Ctkp%3ABk9SR4SM_YzXYA (https://www.ebay.com/itm/325309029169?epid=1400242944&hash=item4bbdeddb31:g:qjAAAOSw-GNi~did&amdata=enc%3AAQAHAAAAoDongduZ9OKRFo20SQM3ytETKrD8C%2F%2By7T3I3ORHH4jd9vtjWk7TNPYq%2BZ4yj7BubEglOpFhqXCcYRd8dy%2FKy301iOxBnj4duOA%2B4T5NkLsyPypXadQrDvXxBP%2B2%2F%2F7DvmGn9UtsU9M%2BUd2AirSnK32Do6wWwEQmU3HBAuAbzqSynAnp5fRmmzF3TWZYyN%2BdEXM%2B2v1%2FlYS7gfcjpZ46OSo%3D%7Ctkp%3ABk9SR4SM_YzXYA)

41:00  Taking it apart.    Hummm.  Small diameter PTCs.   Thicker than what I have seen on the really cheap meters.   May hold up. 

43:35 Brymen vs Fluke, input protection, who's the leader???

50: pulls the main PCB out. 

51: under NDA. 

53: trace wiggles and poor layout

55:19 I missed something.  He reads a comment that is shown in the chat about the meter not being good enough for Dave's branding.   
I thought that about the 121GW. 

Ok, that's the end.   I gave the video a thumbs up.  Meter seems alright but isn't something I would have a use for.   
Title: Re: Handheld meter robustness testing
Post by: TCbystander on August 20, 2022, 02:18:41 pm
While I think some of his testing being is not always directly useful, except for entertrainment, one thing I do value him for is irreverence and following facts where they take him. And he honestly documents data as it is, good and bad...

-40 degrees, 50K rotations, 100ft dropping, 14K transients, etc...  seems like an ElectroBoom review, just for fun. Almost zero probability of this use. (I won't ever use it above 1000V (or even 400V), and if this happens will be 15K, 30K, or 100K? doesn't matter, this is Very Far from the Max Specs).


It is not merely a matter of the rated voltage 1kV you use and test your meter. If a meter is claimed to be rated to CAT IV 1kV meeting the IEC 61010 series in its user's manual, for example, it has to survive the IEC transient test requirement of 12kV from a hybrid impulse generator with a source impedance of 2 Ohms. It is a 1.2/50uS OCV + 8/20uS SCC combo waveform capable of delivering 6000A peak currents. It resembles the magnitude of transients at the source of the building's MAINS. If the meter failed the test, it failed the manual specs it claimed IMHO.  :phew:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 20, 2022, 04:31:42 pm
It is not merely a matter of the rated voltage 1kV you use and test your meter. If a meter is claimed to be rated to CAT IV 1kV meeting the IEC 61010 series in its user's manual, for example, it has to survive the IEC transient test requirement of 12kV from a hybrid impulse generator with a source impedance of 2 Ohms. It is a 1.2/50uS OCV + 8/20uS SCC combo waveform capable of delivering 6000A peak currents. It resembles the magnitude of transients at the source of the building's MAINS. If the meter failed the test, it failed the manual specs it claimed IMHO.  :phew:

Possibly true depending how you interpret the standards.   We've had a several discussions about this and I spoke with two of the large manufactures about it early on.  There seems to be no consensus.  If you have any data (you work in this area), we would like to hear your take on it. 

I also want to again be very clear that the tests I perform have little to do with the safety standards.   Outside of basing my open circuit voltage waveforms on the standards (and still with a twist),  they really share no common ground.   This is covered in the FAQ.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 20, 2022, 08:18:12 pm
(...)
Ok, that's the end.   I gave the video a thumbs up.  Meter seems alright but isn't something I would have a use for.   
I think the meter might be alright as well with protection well above your average chinese product, but the fact the rotary switch is in the center and not on the side is a big limiting factor for the main audience of clamp meters (electricians). AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways). The one detracting factor I noticed was indeed the battery access - the threaded screws are a huge turnoff, especially for electricians that will put it to more use, since they don't carry two instruments to a job but only one that does everything.

I would get one if it is priced competitively, but the UT210E is indeed hard to beat for the electronics hobbyist.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 20, 2022, 08:40:14 pm
(...)
Ok, that's the end.   I gave the video a thumbs up.  Meter seems alright but isn't something I would have a use for.   
I think the meter might be alright as well with protection well above your average chinese product, but the fact the rotary switch is in the center and not on the side is a big limiting factor for the main audience of clamp meters (electricians). AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways). The one detracting factor I noticed was indeed the battery access - the threaded screws are a huge turnoff, especially for electricians that will put it to more use, since they don't carry two instruments to a job but only one that does everything.

I would get one if it is priced competitively, but the UT210E is indeed hard to beat for the electronics hobbyist.

In my every-day tools I carry a Fluke T5-1000 and a Fluke 87V, as well as a Fluke NCV voltpen. I've also got specialist clamps for harmonics measurement, and earth spike testing, and a Fluke 1653 for installation testing. I have no issues carrying all these as and when I need them.   :-//

I can have 150kg or so of tools in my car sometimes, having an all-in-one meter just isn't even on my radar.
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 20, 2022, 09:29:22 pm
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).

I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T  :-DD). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.

Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 20, 2022, 10:30:45 pm
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).

I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T  :-DD). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.
That is pretty neat indeed and I can see its practical aspects. :-+

Although I wonder if it weakens the housing.

I tried to find the OEM but to no avail. I tried CEM, Mastech, Uni-T and Appa.
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 20, 2022, 10:48:39 pm
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).

I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T  :-DD). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.
That is pretty neat indeed and I can see its practical aspects. :-+

Although I wonder if it weakens the housing.

I tried to find the OEM but to no avail. I tried CEM, Mastech, Uni-T and Appa.

It looks like they did the housing pretty well. There is additional plastic ribbing to reinforce the display and input jacks.

I can't say for sure who the OEM is, but the interior build looks suspiciously similar to my Uni-T 210e. It appears to be (the scratched off the label) the same DM1106 controller chip. If they weren't made by the same OEM, they appear to have been based off the same reference design.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 20, 2022, 11:14:38 pm
Looks like they used two 5mm PTCs in series rather than adding the surge rated resistors we commonly see.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 20, 2022, 11:22:48 pm
Looks like they used two 5mm PTCs in series rather than adding the surge rated resistors we commonly see.   

If you are talking about that Ideal meter, then yup... they used two PTC in series (Uni-T style) instead of the surge resistors.

Interestingly, I did look it up and it has a legit UL certification.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 20, 2022, 11:23:29 pm
Non-destructive testing of the Keysight U1282A.   

https://www.youtube.com/watch?v=4S5va8KOjLc (https://www.youtube.com/watch?v=4S5va8KOjLc)
Title: Re: Handheld meter robustness testing
Post by: tautech on August 20, 2022, 11:41:05 pm
LOL, frozen KS !
Would you like ketchup with that Sir ?  :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 21, 2022, 01:12:44 am
LOL, frozen KS !
Would you like ketchup with that Sir ?  :-DD

Brymen specs that 789's operating temperature from -20C  to 55C.  They spec the BM869s from 0 to 45C.  Both seems to have no problems even as low as -40.   I was surprised when the Keysight's internal temp was back up to just under -20C and the meter was still having some problems.   Keysight specs the U1282A's operating temperature from -20 to 55C, just like the Brymen BM789. 
 
Of course, none of these companies provide anything as far as chemical compatibility and some may suggest that these solvents are not something a meter would normally get exposed to.  I was glad the LCD's plastic lens wasn't damaged like the ANENG meters but was disappointed to see the lettering so easily removed. 

I don't think the slow autorange will surprise anyone.  Dave showed how bad it was during his review and commented on it, which is why I was so surprised to see it used in the 121GW.  You could see they tried to improve the 121.   

***
Add KS specs.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 21, 2022, 01:36:28 am
That Keysight U1231A was damaged beyond repair at 5kV 100us FWHH 2 ohm source.  The same level that sent the UNI-T UT139C to the recycle bin.  What level will take out the U1282A?  Add your vote.

***
I like when things repeat and expect it to fail at the same level the previous Keysight was damaged at.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 21, 2022, 01:42:58 am
That Keysight U1231A was damaged beyond repair at 5kV 100us FWHH 2 ohm source.  The same level that sent the UNI-T UT139C to the recycle bin.  What level will take out the U1282A?  Add your vote.

***
I like when things repeat and expect it to fail at the same level the previous Keysight was damaged at.   

Since the 1231 failed near the CATIII600 6k transient its rated for I expect the 1282 to be near it's CATIV600v rating of 8k.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 21, 2022, 01:58:55 am
What about some lighter solvents like IPA? I don't often use racing fuel on my bench but the IPA comes out quite often.

Then there's the acetone ... I try not to use that one the bench though. :scared:

I expect acetone would make a mess of just about any meter but these are supposed to be tough and "industrial". Maybe try it on some of the less important lettering.  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: floobydust on August 21, 2022, 01:59:29 am
Last winter I needed to measure battery voltage on a friend's SUV at -35°C (-31°F) before giving it a boost.
Fluke I don't use on cars because it gets banged up and oil/dirt on it. Well, car toolbox has ANENG AN8008 and... it lasted about 1 minute!
First the rotary switch was making bad contact and took a few spins to stop that, then the push buttons got stiff and stayed stuck down, then the PVC test leads got rock hard. I was hoping only the LCD would freeze lol. It went pretty badly. I was surprised to see how many aspects failed, I've never had a multimeter crater like that.
I think low temp testing needs to go beyond the LCD fluid freezing. The mechanical - pushbuttons and rotary switch crater too.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 21, 2022, 03:37:22 am
That Keysight U1231A was damaged beyond repair at 5kV 100us FWHH 2 ohm source.  The same level that sent the UNI-T UT139C to the recycle bin.  What level will take out the U1282A?  Add your vote.

***
I like when things repeat and expect it to fail at the same level the previous Keysight was damaged at.   

Since the 1231 failed near the CATIII600 6k transient its rated for I expect the 1282 to be near it's CATIV600v rating of 8k.
Considering that none of what I show follows IEC standards or has anything to do with the CAT ratings of the meters, seems like as good a guess as any.    The waveform from the newer generator has a 100us FWHH and only about 20J so the current will roll off fairly fast by comparison.   If it makes it to the higher voltage generator, that uses a 50us FWHH and is even lower energy.   Still....  how much energy does it take to damage a SOT23?
Title: Re: Handheld meter robustness testing
Post by: tautech on August 21, 2022, 03:41:39 am
That Keysight U1231A was damaged beyond repair at 5kV 100us FWHH 2 ohm source.  The same level that sent the UNI-T UT139C to the recycle bin.  What level will take out the U1282A?  Add your vote.

***
I like when things repeat and expect it to fail at the same level the previous Keysight was damaged at.   
Well if it fails we know why:
For professional and industrial use only.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 21, 2022, 03:47:07 am
What about some lighter solvents like IPA? I don't often use racing fuel on my bench but the IPA comes out quite often.

Then there's the acetone ... I try not to use that one the bench though. :scared:

I expect acetone would make a mess of just about any meter but these are supposed to be tough and "industrial". Maybe try it on some of the less important lettering.  :popcorn:
I doubt I will add any others to the test but you are certainly free to run your own tests with what ever cocktail you can come up with.   Please post the results if you do.   

I had damaged the plastics on my meters that I use in the garage.   That Fluke 97 scope meter that was used in a garage has a lot of damage from I expect gasoline or brake cleaner.   This is really why I started looking at them.    A few people have asked about brake cleaner as well which can be pretty hard on plastics as well.   I think it was the methanol that stripped the lettering off the 121GW where that VP fuel had no effect.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 21, 2022, 09:45:54 am
The other Keysight slightly underperformed in the zapping tests.

I'll go with 6-7kV, slightly under the 8kV of the CAT IV 600V rating.

There's no way it's going to go up to 10kV+ like the Flukes and Brymens.  :box:

Edit: Maybe I could do some research and look at some teardown photos before opining, but that wouldn't be me.  :)
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 21, 2022, 06:02:32 pm
Non-destructive testing of the Keysight U1282A.   
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.

Another aspect: when you rotated the switch after the low temp tests, was the meter already back at a specified temperature of at least -20ºC? The reason is that the material might have become brittle at such low temperature and rotating it might degrade it (microfissures?) which would add another variable to the rotary switch tests.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on August 21, 2022, 06:05:37 pm
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).

I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T  :-DD). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.
That is pretty neat indeed and I can see its practical aspects. :-+

Although I wonder if it weakens the housing.

I tried to find the OEM but to no avail. I tried CEM, Mastech, Uni-T and Appa.

It looks like they did the housing pretty well. There is additional plastic ribbing to reinforce the display and input jacks.

I can't say for sure who the OEM is, but the interior build looks suspiciously similar to my Uni-T 210e. It appears to be (the scratched off the label) the same DM1106 controller chip. If they weren't made by the same OEM, they appear to have been based off the same reference design.
Thanks for sharing the pictures; indeed the bottom display seems sturdy.

Looking at the PCB silk screen, it seems to me an original design from Ideal: the model number 61-757 is shown in both PCBs.  :-+
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 21, 2022, 07:02:19 pm
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.

May I suggest comparing the Hycon chip datasheet/pinout with the "custom" chipset in the BM789.  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 21, 2022, 07:06:11 pm
AFAIK the vertical reading tends to be preferred by this audience as well (in contrast to sideways).

I have an Ideal branded clamp meter (Pretty sure it's actually a Uni-T  :-DD). And they have this really neat dual display. I was expecting it to be gimmicky, but I have used the display on the end of the meter often.
That is pretty neat indeed and I can see its practical aspects. :-+

Although I wonder if it weakens the housing.

I tried to find the OEM but to no avail. I tried CEM, Mastech, Uni-T and Appa.

It looks like they did the housing pretty well. There is additional plastic ribbing to reinforce the display and input jacks.

I can't say for sure who the OEM is, but the interior build looks suspiciously similar to my Uni-T 210e. It appears to be (the scratched off the label) the same DM1106 controller chip. If they weren't made by the same OEM, they appear to have been based off the same reference design.
Thanks for sharing the pictures; indeed the bottom display seems sturdy.

Looking at the PCB silk screen, it seems to me an original design from Ideal: the model number 61-757 is shown in both PCBs.  :-+

It's definitely an original design. Ideal has a patent on that display layout so only their meters have it. My meters is one of the first ones sold and I had a minor issue when I first got it. I ended up on the phone with one of their engineers who confirmed that they contract with "A major Asian meter manufacturer". The wouldn't say which one, so any exact OEM guess is speculation.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 21, 2022, 07:19:25 pm
Non-destructive testing of the Keysight U1282A.   
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.

Thanks. 

While I do provide several opportunities for viewer's to offer their suggestions BEFORE conducting these tests,  "hindsight is 20-20", "Coulda Shoulda  Woulda",  "it is what it is" all come to mind.  Now if you are planning to repeat the test,  one viewer had asked about injecting a signal at a fixed frequency to see if the meter's clock  is showing down.  This seems like it would have some merit and something for you to consider.   I am sure a few of us would enjoy watching it but for me, I've seen what I wanted to see.     

Another aspect: when you rotated the switch after the low temp tests, was the meter already back at a specified temperature of at least -20ºC?

From the video, the meter was stored at -40C for well over an hour and then thermal shocked when I rotated the switch to ohms.   From the video we can see the internal temp was reporting  -24 when I tried it again,  then 0. 

The reason is that the material might have become brittle at such low temperature and rotating it might degrade it (microfissures?) which would add another variable to the rotary switch tests.
   
If Keysight's choice of materials have a problem with these few rotations, that's really poor.  From my early days we designed to -40 operating temps and we used plastics in many of these designs.   Many of these parts were not stationary.   Now, don't get me wrong.  Seeing that glass filled spring fail prematurely as it did doesn't give me any confidence in their mechanical designers abilities.   Still, I also have no plans to start treating this meter with kid gloves.   If the plastics fail because of the temperatures, vapors from the gasoline seeping into the plastics, from the UV off the sun,  or the shock of being dropped so be it.     
         
Obviously one shouldn't expect my home hobby testing is going to be conducted like a professional PV test where we may run 50 samples under a very controlled environment.  Of course, the costs in setting up such a lab and the time invested in conducting such tests would far exceed what I would be willing to donate.   I suspect this is why we don't see many reviews doing much more than collecting free meters to unbox and give their 5 star professional rating.   Doing even the small bit I show takes a lot of time, effort and resources.       
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 21, 2022, 07:24:08 pm
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.

May I suggest comparing the Hycon chip datasheet/pinout with the "custom" chipset in the BM789.  :popcorn:

I'll leave the reverse engineering to others.   It's certainly something you could do.  Anytime I have dove into a design, it was to get some idea why a meter failed my tests or how to improve it. 
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 21, 2022, 07:32:02 pm
Great testing, Joe! I only wish you had put in the chamber the meter with the same Hycon chipset to see if we could further isolate the root cause of the issue down to the processor/chipset itself (my best bet, since the meter became "frozen") or another component (XTAL, voltage regulator, etc.). From where we see, there is a chance that Brymen's chipset might be better fabricated than Hycon, but we can only speculate.

May I suggest comparing the Hycon chip datasheet/pinout with the "custom" chipset in the BM789.  :popcorn:

I'll leave the reverse engineering to others.   It's certainly something you could do.  Anytime I have dove into a design, it was to get some idea why a meter failed my tests or how to improve it.

I wasn't expecting you to reverse engineer the meter. My comment was to rsjsouza in reference to his question that the Brymen chipset might be fabricated better than the Hycon.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 22, 2022, 10:56:46 pm
Ran a few tests that viewer had asked about including looking at some smaller capacitors and measuring the burden voltage.    I also started running the potentially destructive tests. 

https://www.youtube.com/watch?v=BgoeNYmTlDE (https://www.youtube.com/watch?v=BgoeNYmTlDE)
Title: Re: Handheld meter robustness testing
Post by: Trader on August 23, 2022, 08:35:27 pm
Pretty cool tests, seems to be a very robust DMM.

Thanks for explaining about the testing box.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 23, 2022, 10:08:41 pm
Pretty cool tests, seems to be a very robust DMM.

Thanks for explaining about the testing box.
If you were confused about how "...useless is to use a "crappy box" with a lot of uncalibrated "references"..",  chances are good that there are others who are also not understanding what is being shown.  While the threads now several years old and the basics are documented and have been explained many times,  I certainly understand not everyone is going to take the time to do any research before chiming in with their expert opinion.   

From my viewpoint, it's too early to say if the U1282A is electrically robust or not.  It's well known that I used the runner up from the first $50 shootout to set the bar for what I consider robust.  This is why the transient generator is limited to 5.8kV.   If your product can't survive to the level that the $50 Amprobe AM510 can, IMO, that's not very impressive.    Then again, if all you had were UNI-T products to compare with it, the Keysight is surely a notch above them as the grill starter normally does them in.   Of course, that's not my position and I have a lot of data to back it up.  I would have liked to ran the Keysight open fused at 2kV like the standard calls for and just see what happens.  It's not been a problem but this is the first time I have seen a meter load my supply like this. 

From a chemical robustness, hard to say.  It's rare we have seen these two chemicals cause any problems.  I was very surprised that a company like Keysight would not have worked with a company that knew what they were doing.  Obviously they are out there. 

I'm not sure about the switch until we run it.   The one to beat is still that Fluke 17B+.   Both Brymen and Fluke have shown us they know how to design a switch that will last.  Even that last UNI-T meter I looked at held up much better than I was expecting.    The first Keysight made it a few thousand cycles was all.  I can tell you that the spring feels very stiff.  We will know soon enough. 
Title: Re: Handheld meter robustness testing
Post by: Trader on August 23, 2022, 11:09:06 pm
I don't think the testing box is "useless", yes you are using it just to know if the meter still working; but I'm sure that could be much better if you at least provide a table with the "correct" value of each reference, maybe the meter could be a little off after the tests.

I know, nothing there is accurate and can vary a little when the temperature or power supply changes, but at least is better than not knowing the correct value.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 24, 2022, 12:01:05 am
I don't think the testing box is "useless", yes you are using it just to know if the meter still working; but I'm sure that could be much better if you at least provide a table with the "correct" value of each reference, maybe the meter could be a little off after the tests.

I know, nothing there is accurate and can vary a little when the temperature or power supply changes, but at least is better than not knowing the correct value.

"Useless" and "crappy" were your choice of words, not mine.   If you like calling viewer's pussies and such just be aware we are reading... 

I have not yet seen a meter that when damaged exhibited a subtle shift in readings.   Still, these are relative measurements, not absolute.   It sounds like you may not understand that there is a difference.   

Correct values?   Let's see, there's a pot that I set manually to get some idea if the temperature circuit is still functional.   There's even a mark on the box for roughly 500C.  For the resistors, I provide their tolerances.  At one time, I published the values of the caps using my RLC meter but again, it's not in cal.    It would add no value to do anything beyond this.   Again, I assume the meters are within their manufactures specs when I buy them.   Had my goal been to verify their calibration,  I would rent a calibrator.   That said, this does seem to be Defpom's area of interest.    Mine is how robust these meters are.  While I would expect reviewer's like Defpom would rarely damage a meter during a review and should have a very large collection,  there's a reason I never show a Keysight handheld meter as a comparison.  Mine went to the recycle bin.  It just wasn't robust enough to make the cut.     
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 24, 2022, 02:29:01 am
Again, I assume the meters are within their manufactures specs when I buy them.   Had my goal been to verify their calibration,  I would rent a calibrator.   That said, this does seem to be Defpom's area of interest.    Mine is how robust these meters are.   

And that's a good thing. Having different reviewers that specialize is great for the folks watching. It allows a reviewer to concentrate on and get good at their area of interest and we can then watch a few different reviews to gain indepth knowledge from all.

It goes back to the saying "Jack of all trades master of none". When watching a review my preference is to watch different folks that are good at what they care about so that I know I am getting good Indepth information from each.

Honestly the one thing I wish was covered in the accuracy review videos is long term drift. I would be great to see the drift for each meter at 1, 2, and 5 years on... Of course this is wholly impractical, so I realize it will never happen!  :-//
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 24, 2022, 03:14:24 am
I would have liked to ran the Keysight open fused at 2kV like the standard calls for and just see what happens.  It's not been a problem but this is the first time I have seen a meter load my supply like this. 

Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.  :wtf:

For comparison the BM78x uses a of 5MOhm resistor per amp jack for the lead sense which if my math is correct it would be expected that the current draw with 2KV applied would be around 0.4ma and Brymen used 2W resistors to handle the power (expected 0.8W) dissipated.  That's a significant difference between the different meters.

Did you run this test on the BM78x meters? I don't remember seeing it in any of the videos.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 24, 2022, 03:43:36 am
“A jack of all trades is a master of none, but often times better than a master of one.”

Attached showing the last time I checked my UT61E, representing almost 6 years of data.  Of course, this meter is highly modified for educational purposes only.   


Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.  :wtf:

You're catching on!!  If I had a larger supply, I may have ended that meter right then and there.   It's certified and would have been subjected to this.... or is there more to the story..

For comparison the BM78x uses a of 5MOhm resistor per amp jack for the lead sense which if my math is correct it would be expected that the current draw with 2KV applied would be around 0.4ma and Brymen used 2W resistors to handle the power (expected 0.8W) dissipated.  That's a significant difference between the different meters.

Did you run this test on the BM78x meters? I don't remember seeing it in any of the videos.

You know I did!   That poor meter was under the microscope, just like every other meter I look at. 

Maybe Defpom has a larger supply and would be willing to sacrifice their free meter?   I paid for mine and would be more than willing to run it.  Sort of the whole point of the channel.   

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 24, 2022, 04:10:57 am
To save you time searching.

Chemical: 21:44
Open Fuse: 22:55
Finally, the meter is damaged at 12kV (more than double what my first Keysight was damaged at):  57:47
After 50,000 full rotations on the switch: 1:15:00

https://www.youtube.com/watch?v=UY9Myo5ngPQ (https://www.youtube.com/watch?v=UY9Myo5ngPQ)
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 24, 2022, 04:15:20 am
Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.  :wtf:

Yep. This needs investigating... where is all that power going?

Does it do it with the switch in the "off" position?

Edit: I guess it survived though, and an 8kV transient is only going to push something like 200mA through it for an instant, it will probably survive that, too.  :-//

OTOH it doesn't inspire confidence. It doesn't say "we made it as good as possible!", it asks "where else did they cut corners?"
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 24, 2022, 04:17:53 am
To save you time searching.

Chemical: 21:44
Open Fuse: 22:55
Finally, the meter is damaged at 12kV (more than double what my first Keysight was damaged at):  57:47
After 50,000 full rotations on the switch: 1:15:00

https://www.youtube.com/watch?v=UY9Myo5ngPQ (https://www.youtube.com/watch?v=UY9Myo5ngPQ)

Thanks for the link. I probably don't remember that test because it.was too uneventful.  :-DD

I honestly think that poor meter got the most scrutiny of any of your videos I watched. It certainly says something when a meter takes that much poking and proding and comes out that good. It certainly seems the Flukes and Brymens are in a special league with little company!
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 24, 2022, 04:21:25 am

Attached showing the last time I checked my UT61E, representing almost 6 years of data.  Of course, this meter is highly modified for educational purposes only.   

Thanks for that. It's interesting data.

It's.too bad the Uni-T aren't very robust. They seem like great measuring meters and certainly fall under the bang for buck category. If they made them just a bit more robustly they could be great meters! I really wonder how muchlre it would cost them to make them just a bit better. It seems they are willing to spend money on parts in their better meters.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 24, 2022, 11:18:26 am
It's.too bad the Uni-T aren't very robust. They seem like great measuring meters and certainly fall under the bang for buck category. If they made them just a bit more robustly they could be great meters! I really wonder how muchlre it would cost them to make them just a bit better. It seems they are willing to spend money on parts in their better meters.

I say that about every single meter I look at. It's very possible that they just lack the engineering skills. 

Thanks for the link. I probably don't remember that test because it.was too uneventful.  :-DD

I honestly think that poor meter got the most scrutiny of any of your videos I watched. It certainly says something when a meter takes that much poking and proding and comes out that good. It certainly seems the Flukes and Brymens are in a special league with little company!
It's possible that because both the BM786&9 were still in the development stages (not yet available for purchase) that I spent more time going over them both.   It's rare we get to look at preproduction products and have an opportunity to provide a company feedback that could be used to possibly release a better product.   Dave had shown us the meter long before I became involved. I guessing he was testing them and uncovering a few problems as well.   

Dave provided me with the same opportunity with the 121GW but the end results were much different.  You may remember I had pulled those videos after Dave's comments about them confusing viewers.   After waiting two years after the 121GW's release, I bought two new ones and was surprised of how many of my original findings still existed.  This is the difference Brymen brings.  Brymen has proven they are interested in producing a good product. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 24, 2022, 05:08:49 pm
It's.too bad the Uni-T aren't very robust. They seem like great measuring meters

There's meters for half the price that are "good measuring meters".

This is the difference Brymen brings.  Brymen has proven they are interested in producing a good product. 

QFT.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 25, 2022, 11:49:54 am
Wait... It looks like your Applied KilloVolts power supply is capable of 40ma. That would imply that the 1282A is dissipating about 80W somewhere.  :wtf:

Yep. This needs investigating... where is all that power going?

Does it do it with the switch in the "off" position?

Edit: I guess it survived though, and an 8kV transient is only going to push something like 200mA through it for an instant, it will probably survive that, too.  :-//

OTOH it doesn't inspire confidence. It doesn't say "we made it as good as possible!", it asks "where else did they cut corners?"

I did not try this test in the off position, only in the Amps range that was being tested at that time.   

Looks like I could borrow a supply what would get us to 150mA.  The standard calls for 500VA but it may be enough to damage the meter.    I think the first step is to trace this section out and see what these top Keysight engineers have done to cause such a high load.   
Title: Re: Handheld meter robustness testing
Post by: HKJ on August 25, 2022, 12:14:09 pm
I did not try this test in the off position, only in the Amps range that was being tested at that time.   

Looks like I could borrow a supply what would get us to 150mA.  The standard calls for 500VA but it may be enough to damage the meter.    I think the first step is to trace this section out and see what these top Keysight engineers have done to cause such a high load.

You high voltage supply must be very weak, I had expected the meter to start smoking (There is nothing in the meter that can handle more than a few Watt for much time).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 25, 2022, 12:18:18 pm
I did not try this test in the off position, only in the Amps range that was being tested at that time.   

Looks like I could borrow a supply what would get us to 150mA.  The standard calls for 500VA but it may be enough to damage the meter.    I think the first step is to trace this section out and see what these top Keysight engineers have done to cause such a high load.

You high voltage supply must be very weak, I had expected the meter to start smoking (There is nothing in the meter that can handle more than a few Watt for much time).

:-DD I think this is exactly the problem!!  I pulled the meter back apart and they are using a 2.5M to limit the current.  Should be well under a mA.   I believe I had turned down the current limit at one point.   I'll recheck that function before moving forward.     
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 25, 2022, 01:01:01 pm
Looks like that was the problem.  Makes much more sense now.   I readjusted the supply.  Shown at 2kV with 1Meg load.  Their 2.5M resistors should handle the 1.6W.   


Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 27, 2022, 07:02:28 pm
Looking forward to part 5!
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 28, 2022, 08:16:59 am
Such a difference in how we tested it.

Doesn't it deserve to dropped off the roof like the others?
Title: Re: Handheld meter robustness testing
Post by: tautech on August 28, 2022, 09:31:05 am
Such a difference in how we tested it.

Doesn't it deserve to dropped off the roof like the others?
Why ?
He's already dead Jim Fungus according to Joe.  :)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 28, 2022, 03:03:19 pm
Such a difference in how we tested it.
Doesn't it deserve to dropped off the roof like the others?
I would like to run the life test on the switch before doing anything else.  The question now is do all the prongs on the detent spring crack like before?   
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 28, 2022, 06:36:51 pm
I would like to run the life test on the switch before doing anything else.  The question now is do all the prongs on the detent spring crack like before?

Of course...  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 28, 2022, 06:44:16 pm
I would like to run the life test on the switch before doing anything else.  The question now is do all the prongs on the detent spring crack like before?

Of course...  :popcorn:
I suspect the same but that's why we test them. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 28, 2022, 07:17:19 pm
I suspect the same but that's why we test them. 

On the bright side: It might be a short test...  :-DMM
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 28, 2022, 07:37:29 pm
On the bright side: It might be a short test...  :-DMM

Well...  I am thinking even if the spring is damaged as before, we leave the meter together and just let it run out the full 50,000 cycles to get an idea what else goes wrong.   Like the first Keysight meter I looked at, this one was damaged bad enough that I doubt I will attempt to repair it.   If it were Brymen, I am sure I could get parts but based on my previous attempts to open a conversation with Keysight, I doubt I would get anywhere.  If Dave would provide me with the broken up PCB from his, maybe the ICs  could be salvaged to save it.   I had asked before about getting it to pull the front end chip.  No luck.  So I am fully expecting it to hit the recycle bin.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 29, 2022, 01:32:44 am
Not much to say beyond she's dead Joe.

https://www.youtube.com/watch?v=MEfUDnKJ4z0 (https://www.youtube.com/watch?v=MEfUDnKJ4z0)
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 29, 2022, 02:27:34 am
Not much to say beyond she's dead Joe.

https://www.youtube.com/watch?v=MEfUDnKJ4z0 (https://www.youtube.com/watch?v=MEfUDnKJ4z0)

Well that's disappointing. I was hoping it would do better than that.

One thing that (too late now...) would have been interesting to know is if it was damaged in that hit when the meter shut off, or if the final hit after it turned off is what did the actual damage. What I wonder is if the fact that the DMM chipset would have (likely) been turned off for that last hit, thus taking the range resistors out of circuit, did the meter get damaged worse that it would have if the chipset was still powered? Again it should have survived, but that last hit was (in my opinion) a little unfair due to the fact that no-one would be trying to measure with a meter when it is so obviously in a non-functional state with the display off.
Title: Re: Handheld meter robustness testing
Post by: Muttley Snickers on August 29, 2022, 02:28:43 am
 :-BROKE :( :'(

I think it may have been mentioned already, but perhaps you could ask Dave what he did with the U1282A he took down the canyon and if he would be willing to post you the board.

It would be nice to see the rotary selector test done with a fully operational meter to monitor it for any weird stuff during the cycle testing. With the types of testing I use these meters for I am probably more likely to wear out the selector switch well before being anywhere near a 5kV transient.
Title: Re: Handheld meter robustness testing
Post by: Trader on August 29, 2022, 03:40:36 am
Failing in the 5KV Transient Voltage test, means that this DMM is CAT IV for up 150V, but CAT III for 151-300V ?

https://www.digikey.com/en/blog/what-are-multimeter-cat-safety-ratings (https://www.digikey.com/en/blog/what-are-multimeter-cat-safety-ratings)
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 29, 2022, 09:12:06 am
Failing in the 5KV Transient Voltage test, means that this DMM is CAT IV for up 150V, but CAT III for 151-300V ?

The CAT documents only say that meters must protect the user. They don't say that the meter has to survive.

OTOH a meter that survives seems more desirable to me.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 29, 2022, 12:28:33 pm
The CAT documents only say that meters must protect the user. They don't say that the meter has to survive.

OTOH a meter that survives seems more desirable to me.
History once again repeats.  Again, the thread is not about meeting a safety standard.  Of course it does keep coming up.  The question I have for you  is if you finally took the time to speak with someone who may actually have the background needed to answer this?  Or it is just the same old posting your feelings about a papers I doubt you have ever seen let alone read?   Welcome to the internet.   

:-BROKE :( :'(

I think it may have been mentioned already, but perhaps you could ask Dave what he did with the U1282A he took down the canyon and if he would be willing to post you the board.

It would be nice to see the rotary selector test done with a fully operational meter to monitor it for any weird stuff during the cycle testing. With the types of testing I use these meters for I am probably more likely to wear out the selector switch well before being anywhere near a 5kV transient.
I asked him about it years ago as a parts meter to repair the prototype 121GW.  No luck.  Too bad really as it could have very well saved this meter from the recycle bins. 

I've damaged a lot of meters that were not able to be salvaged.  Most of the higher cost meters had enough protection that at least saved the parts that your not going to find at the local distributor.  Even the UNI-T UT181A could be repaired.  Keysight doesn't appear to attempt to protect these unique parts like many of their competitors.   
 
For the life cycle test, the meters are unpowered, their batteries pulled.   I collect data on the switch contact resistance and look at how the switch wears.  It would be nice to be able to power it up after the face but it's certainly not a requirement.   

Well that's disappointing. I was hoping it would do better than that.

I'm also very disappointed but not at all surprised by the outcome.   It's an old design and I would assume the same group designed their entire DMM product line.  When you copy paste, this is what you get.   On the other hand, I am pleased that the testing is so reproducible.   

One thing that (too late now...) would have been interesting to know is if it was damaged in that hit when the meter shut off, or if the final hit after it turned off is what did the actual damage. What I wonder is if the fact that the DMM chipset would have (likely) been turned off for that last hit, thus taking the range resistors out of circuit, did the meter get damaged worse that it would have if the chipset was still powered? Again it should have survived, but that last hit was (in my opinion) a little unfair due to the fact that no-one would be trying to measure with a meter when it is so obviously in a non-functional state with the display off.

 :-DD I would imagine there are many people who feel several of the tests I conduct are a little unfair!!  After a few years, I'm sure I've heard it all.   I do wonder at times if making these results public has had any impact on the companies who develop these meters or the people who buy their products. 

I am looking for what level the meters are damaged.   Just that simple.  Because the transient generator is semi-automatic, I will typically walk away from it.   If you were to watch where I have damaged other meters, I suspect you will note several cases where the meters are subjected to the full 5 cycles no mater the outcome of each individual transient.   I dare say that in some cases I will even go so far as to finish up the remaining transients for a given level.    If it's damaged, its damaged.   If I roast it to a crisp or pop a SOT23, what is recorded is still the same, the meter failed at level X.   
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 29, 2022, 01:13:47 pm
Quote from: joeqsmith link=topic=48998.msg4387375#msg4387375

One thing that (too late now...) would have been interesting to know is if it was damaged in that hit when the meter shut off, or if the final hit after it turned off is what did the actual damage. What I wonder is if the fact that the DMM chipset would have (likely) been turned off for that last hit, thus taking the range resistors out of circuit, did the meter get damaged worse that it would have if the chipset was still powered? Again it should have survived, but that last hit was (in my opinion) a little unfair due to the fact that no-one would be trying to measure with a meter when it is so obviously in a non-functional state with the display off.

 :-DD I would imagine there are many people who feel several of the tests I conduct are a little unfair!!  After a few years, I'm sure I've heard it all.   I do wonder at times if making these results public has had any impact on the companies who develop these meters or the people who buy their products. 

I am looking for what level the meters are damaged.   Just that simple.  Because the transient generator is semi-automatic, I will typically walk away from it.   If you were to watch where I have damaged other meters, I suspect you will note several cases where the meters are subjected to the full 5 cycles no mater the outcome of each individual transient.   I dare say that in some cases I will even go so far as to finish up the remaining transients for a given level.    If it's damaged, its damaged.   If I roast it to a crisp or pop a SOT23, what is recorded is still the same, the meter failed at level X.

My curiosity not withstanding, running fully automated is the best way to ensure a consistent test across all meters!
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 29, 2022, 01:22:16 pm
The CAT documents only say that meters must protect the user. They don't say that the meter has to survive.

OTOH a meter that survives seems more desirable to me.
History once again repeats.  Again, the thread is not about meeting a safety standard.  Of course it does keep coming up.  The question I have for you  is if you finally took the time to speak with someone who may actually have the background needed to answer this?  Or it is just the same old posting your feelings about a papers I doubt you have ever seen let alone read?   Welcome to the internet. 

I have no read the specs, so I can't comment on the need for the meters to survive, but I do remember Joe showing snippets of the standard and one thing that stands out in my memory is the statement that "the meter shall remain capable of indicating hazardous voltage". This meter certainly was not capable of indicating hazardous voltage after it failed.

Joe one thing that seems to hold true is the meters usually fail on the inputs other than the primary voltage input, usually ohms or (as in this case) mv inputs. How is the specification worded regards those inputs? I know it must take the full input voltage, but does it explicitly state that these secondary (ohms mv, etc) inputs must also be able to survive the same transient testing?

Again I know your testing isn't to test the CAT rating. I am just always amazed when NRTL tested meters fail your robustness tests at voltages lower than the CAT transient tests.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 29, 2022, 02:37:52 pm
I have no read the specs

Nor many people have. They print them on unobtainium.

I do remember Joe showing snippets of the standard and one thing that stands out in my memory is the statement that "the meter shall remain capable of indicating hazardous voltage".

Oh, yeah, that part...

This meter certainly was not capable of indicating hazardous voltage after it failed.

How do you know?

It's certainly possible that there's an LCD segment that turns on via an independent circuit, not via the main CPU. This isn't something that I recall joe ever checking after a meter has failed.

It seems very unlikely, but it really ought to be explicitly tested. Hook it up to +50V with the batteries in and see if anything happens anywhere on screen...  :popcorn:

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 29, 2022, 02:43:25 pm
Quote from: joeqsmith link=topic=48998.msg4387375#msg4387375
...  Because the transient generator is semi-automatic, I will typically walk away from it.  ...
My curiosity not withstanding, running fully automated is the best way to ensure a consistent test across all meters!
Automating the knob rotation for each meter, IMO would be a lot of work with no value added.  Designing a generator that supports both polarities vs swapping the leads, again, I see as little value.   Of course, if we are going to switch out the generator and then automatically test the meters between each level, again a bit of work for what I see as no value added.   
Just an FYI, we do not do this in the real world.


I am certainly not apposed to seeing someone else step up and run similar tests.  I wouldn't mind seeing someone procure an actual combo generator that also supports modes like burst.   Add an ESD gun, calibrator, maybe setup some sort of EMI chamber....   Maybe the holy grail and setup an arc flash lab?   It's all far outside the scope of what I am looking for but it
would be fun to watch.

...
Joe one thing that seems to hold true is the meters usually fail on the inputs other than the primary voltage input, usually ohms or (as in this case) mv inputs. How is the specification worded regards those inputs? I know it must take the full input voltage, but does it explicitly state that these secondary (ohms mv, etc) inputs must also be able to survive the same transient testing?

I'm pretty sure I went over this early on but you would need to read them to know for sure.  I can tell you in Joe's world, they are going to be tested this way before I will ever consider them robust.   

Again I know your testing isn't to test the CAT rating. I am just always amazed when NRTL tested meters fail your robustness tests at voltages lower than the CAT transient tests.

I am amazed when meters are damaged by that stupid little grill starter or if they fail at levels lower than what damaged that $50 Amprobe AM510.   The worse, IMO, are meters like this Keysight that carry a high price tag an are rendered non-repairable. 
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 29, 2022, 03:31:50 pm
I wouldn't mind seeing someone procure an actual combo generator that also supports modes like burst.

May I ask what a combo generator is? I've googled it and diesel generators showed up. How are diesel generators going to fit into these tests?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 29, 2022, 04:05:31 pm
I wouldn't mind seeing someone procure an actual combo generator that also supports modes like burst.

May I ask what a combo generator is? I've googled it and diesel generators showed up. How are diesel generators going to fit into these tests?

I was referring to burst and surge transients from the safety standards that people are talking about.  Have a look:
https://www.ametek-cts.com/products/productgroups/transient-generators-surge-and-burst/surge-generator (https://www.ametek-cts.com/products/productgroups/transient-generators-surge-and-burst/surge-generator)

That said, you may need a genset if you plan to setup an arc flash test lab.
https://www.ecmag.com/section/safety/lets-blow-it-arc-flash-testing (https://www.ecmag.com/section/safety/lets-blow-it-arc-flash-testing)

****
It doesn't hurt to repeat it once again.

I want to be very clear that I really have no interest in the safety standards or if a meter is safe or not.  I do not work in a environment where I deal with high energy circuits.

What I am interested in is if a meter will survive low energy transients.  I am more interested in IEC 61326 than 61010.   This dates to my first DMM (Fluke) that I damaged a few times from low energy transients and it cost a fair amount to repair.   You couldn't give me a Fluke meter up till the time Fungus convinced me to buy that 101.  I had full intentions of watching that meter burn to the ground but it proved to be a very worthy opponent. 

I run the tests out of my own interests and look for things that have damaged my own meters.   This is why you see them being exposed to methanol and gasoline.   It's why I cycle the switches.   And it's why I run these low energy transients.

I'm not suggesting any of this information is useful to viewers.  Maybe it provides some level of entertainment?  Maybe some education?  Increased awareness?  Who knows.   It's not very popular and I am certainly not in it for the money!  :-DD 

***
Site doesn't seem to like dollar signs...
Title: Re: Handheld meter robustness testing
Post by: Chance92 on August 29, 2022, 05:11:16 pm
I wouldn't mind seeing someone procure an actual combo generator that also supports modes like burst.

May I ask what a combo generator is? I've googled it and diesel generators showed up. How are diesel generators going to fit into these tests?

I was referring to burst and surge transients from the safety standards that people are talking about.  Have a look:
https://www.ametek-cts.com/products/productgroups/transient-generators-surge-and-burst/surge-generator (https://www.ametek-cts.com/products/productgroups/transient-generators-surge-and-burst/surge-generator)


Is it similar to a pulse generator like this one:

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 29, 2022, 05:40:25 pm
Is it similar to a pulse generator like this one:

You would need to ask them what standards they adhere to.   The ones I am referring to support both the 1.2us/50us voltage as well as the 8us/20us current waveforms (hence the name, combo generator or combination). 

Doing a search on their site, I do not believe they have support for the IEC standards we are talking about.
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 30, 2022, 03:28:09 am

...
Joe one thing that seems to hold true is the meters usually fail on the inputs other than the primary voltage input, usually ohms or (as in this case) mv inputs. How is the specification worded regards those inputs? I know it must take the full input voltage, but does it explicitly state that these secondary (ohms mv, etc) inputs must also be able to survive the same transient testing?

I'm pretty sure I went over this early on but you would need to read them to know for sure.  I can tell you in Joe's world, they are going to be tested this way before I will ever consider them robust.   

Again I know your testing isn't to test the CAT rating. I am just always amazed when NRTL tested meters fail your robustness tests at voltages lower than the CAT transient tests.

I am amazed when meters are damaged by that stupid little grill starter or if they fail at levels lower than what damaged that $50 Amprobe AM510.   The worse, IMO, are meters like this Keysight that carry a high price tag an are rendered non-repairable.

That's why I am curious about how the standards are worded, and I thought you had a copy (I do not have access to a copy) which is why I asked you how it is worded. I agree completely with your assertion that a robust meter should survive the tests you throw at them. I am mostly curious if the standard omits the transient tests for inputs like ohms, etc as a way to explain how a high end meter like the keysight could pass third party testing, but still fail at your less demanding tests.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 30, 2022, 03:48:51 am
I am mostly curious if the standard omits the transient tests for inputs like ohms

I believe it specifically includes them, that meters have to "fail safely" with all possible combinations of selector switch and input jack.

as a way to explain how a high end meter like the keysight could pass third party testing, but still fail at your less demanding tests.

CAT rating is a safety rating. If the user was in no danger then it's a pass!*

Re: The requirement to show hazardous voltages:

Is there a hard requirement in the standard to indicate unsafe voltages or is is the requirement something more like "never show lower voltages than are actually present"? A blank screen would meet that requirement - if it's not showing you any voltages at all then it's not telling you any lies.

(*) I'm not an expert, I haven't read the standard, this is just my understanding from reading Internet forums. I love being corrected.

Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on August 30, 2022, 05:07:37 am
I am mostly curious if the standard omits the transient tests for inputs like ohms

I believe it specifically includes them, that meters have to "fail safely" with all possible combinations of selector switch and input jack.


But that's your opinion. My question is regarding the actual wording in the specification. How do you know that the meter must be tested on all possible combinations if you have not read the spec?


as a way to explain how a high end meter like the keysight could pass third party testing, but still fail at your less demanding tests.

CAT rating is a safety rating. If the user was in no danger then it's a pass!*

Again, how do you know that the user would not be in danger? Joe's tests have tiny amounts of energy behind them compared to the actual CAT ratings. All his tests demonstrated is that the meter had a breakdown internally and was irreparably damaged at just above half the CAT rating. How do you know that the meter would not fail catastrophically if there was sufficient energy behind the pulse? If you can tell this from Joe's test you are a better expert than I am.

All we know from Joe's testing is that an ESD event with a 5KV or greater potential can irreparably damage the meter. I can tell you one thing. I would NOT be comfortable using a meter that can breakdown internally at half its rating if I were working in an arc flash environment. In that environment it's certainly possible that a minor breakdown inside the meter could turn in to a safety hazard real fast! Again, are you really able to extrapolate safety from Joe's tests? I always thought safety testing must be done with a true combo generator.


Is there a hard requirement in the standard to indicate unsafe voltages or is is the requirement something more like "never show lower voltages than are actually present"? A blank screen would meet that requirement - if it's not showing you any voltages at all then it's not telling you any lies.

(*) I'm not an expert, I haven't read the standard, this is just my understanding from reading Internet forums. I love being corrected.



I am not one to speculate so I will leave this for people who have actually read the standard to answer.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 30, 2022, 07:55:17 am
CAT rating is a safety rating. If the user was in no danger then it's a pass!*
Again, how do you know that the user would not be in danger? How do you know that the meter would not fail catastrophically if there was sufficient energy behind the pulse?

If you go and look up the certifications for this meter you get this:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1577434;image)

ie. Keysight are stating that it meets the relevant standards.

https://regulations.about.keysight.com/DoC/DoC_U1280ANU1280AU1281Aa_10-Aug-2021-05_56_58.pdf (https://regulations.about.keysight.com/DoC/DoC_U1280ANU1280AU1281Aa_10-Aug-2021-05_56_58.pdf)

Edit: I'd be happier if they published some certificate numbers as issued by some independent testers, but they don't. All they say is "The products were tested in a typical configuration with Keysight Technologies test systems."

Maybe Keysight are too cheap to do independent testing and that's why the only marking on the back of the meter is the "CE" mark.


I would NOT be comfortable using a meter that can breakdown internally at half its rating if I were working in an arc flash environment.

So thank joe for making this video and don't buy a Keysight.

Again, are you really able to extrapolate safety from Joe's tests?

Who says I'm extrapolating anything from joe's tests?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 09:16:44 am
...
All we know from Joe's testing is that an ESD event with a 5KV or greater potential can irreparably damage the meter.
...
This is not correct. 

I posted data for the grill starter along with the gun I designed to simulate an ESD event based on the IEC standard.  The transients these both produce are a few ns wide.    Part4 shows applying transients from both.   

I refer to the transient derived from the generator shown in Part 5 as a "surge" but I make it very clear that it is not the same as what is defined by the 61010 low voltage directive.   I've also explained the reason for this.    What damaged the U1282A was this surge waveform, not the ESD. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 09:20:40 am
That's why I am curious about how the standards are worded, and I thought you had a copy (I do not have access to a copy) which is why I asked you how it is worded.

I do and believe I had already covered this.   The standards are available for purchase if you are interested in obtaining them.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 09:46:07 am
I would NOT be comfortable using a meter that can breakdown internally at half its rating if I were working in an arc flash environment.
So thank joe for making this video and don't buy a Keysight.

It certainly made a noise but hard to say.  I ran the U1231A without the case and switch to get some idea what may have happened.

Going back and watching the videos, it appears to be a very similar if not an identical failure mode.  I had ran it with that half cycle generator as well. Not a lot of energy but still gives us some insight.   A few viewers suggested that the damage to the switch contacts what the cause of the problems during the switch life cycle testing.   This time, the plan is to wait to do any further destructive testing until after the switch has been cycle tested. 

https://www.youtube.com/watch?v=ju9JcAzgOeo (https://www.youtube.com/watch?v=ju9JcAzgOeo)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 01:53:34 pm
Quote
Mismatches of inputs and ranges are examples of REASONABLY FORESEEABLE MISUSE, even if the documentation or markings prohibit such mismatch.

The attached image was taken shortly after design an construction of the transient generator (2016).   Shown with 5kV peak, 100us FWHH, no load.  This is the transient that damaged both Keysight meters.   
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 30, 2022, 04:22:59 pm
Quote
Mismatches of inputs and ranges are examples of REASONABLY FORESEEABLE MISUSE, even if the documentation or markings prohibit such mismatch.

The attached image was taken shortly after design an construction of the transient generator (2016).   Shown with 5kV peak, 100us FWHH, no load.  This is the transient that damaged both Keysight meters.

Just out of curiosity, have you looked at the waveform of the grill starter output, across a nominal load of say 10MΩ, to simulate what it would look like to the front end of a typical handheld DMM?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 05:30:07 pm
Just out of curiosity, have you looked at the waveform of the grill starter output, across a nominal load of say 10MΩ, to simulate what it would look like to the front end of a typical handheld DMM?
Well, I am not sure what "typical" would be but I don't think I have a meter that could be simulated with a simple 10M resistor.   Case and point, I modified the UNI-T UT181A's layout to attempt to improve its ability to handle an ESD event.   That PCB is part of the circuit and has inductance, capacitance....   That ESD pulse reaches its peak current in less than 1ns! 

https://www.esdguns.com/content/11-waveform-verification-iec-61000-4-2-waveshape (https://www.esdguns.com/content/11-waveform-verification-iec-61000-4-2-waveshape)

That said, I used the grill starter to demonstrate why the UT61E was damaged and how it could possibly be improve.  That video shows the waveforms while I injected the transient into the meter.   

The other video was Part2 for the UT181A where I show how I actually measure the ESD transients.   Pretty low end setup using my home made targets but that's a side effect when watching a hobbyist at play vs an actual lab.

***
Consider that the surge waveform I apply has a rise time of just over a 1us, compared with the ESD at < 1ns, we can see these two transients are not at all the same.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 05:38:37 pm
My home made target, a section of PCB with embedded resistor, costs maybe a buck.  Add attenuators, connectors, cable call it maybe $100.    Real target, $3500 USD.   

https://www.esdguns.com/esd-calibration-test-targets/118-cst2-4-ghz-2-ohm-esd-target-current-sensing-transducer.html (https://www.esdguns.com/esd-calibration-test-targets/118-cst2-4-ghz-2-ohm-esd-target-current-sensing-transducer.html)
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 30, 2022, 07:59:36 pm
10MΩ should get you in the ball-park though? Maybe with some MOVs or GDTs in parallel...   :-//

My understanding is these piezo ignitors don't pack much of a punch, energy wise, but can deliver maybe 10kV or so, happy to be corrected if wrong.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 09:02:41 pm
10MΩ should get you in the ball-park though? Maybe with some MOVs or GDTs in parallel...   :-//

My understanding is these piezo ignitors don't pack much of a punch, energy wise, but can deliver maybe 10kV or so, happy to be corrected if wrong.


Right.  So a few points.  When I show the UT61E, I show that while the MOVs would be fairly fast and have a fair amount of capacitance, their inductance was too high to make any difference at the frequencies we are considering.   I think I talked about shunting it right at the source (small cap right at the inputs) but that IMO, would be a very bad choice.   I have seen handhelds with intentional spark gaps designed into the artwork, right at the front end.  Bat shit crazy stuff.   In the end, I talked about like any problem, there may be many ways to solve it.  Still, each meter is going to be unique.   


But now I think we get to the crooks of what you are driving at.  You suspect the grill start is putting out 1MegaVolt which unfairly wipes out all of those UNI-T meters.    :-DD

I don't think I ever did a video on it but not all grill starters are alike.  Even if I have two what appear on the outside to be identical grill starters, the waveforms they produce can be drastically different.  They can also change a lot as the cheap springs they use take a set.   If we use 1000V per mm, 10mm air gap for 10kV, I have no doubt that I have one grill starter that will exceed that. 

I wonder too, if I could find a much stiffer spring and maybe shim it, how far I could push one.   I wouldn't be surprised to see one jump 20mm or more depending where you live.   

So, yes, I have a standard reference grill starter that I calibrate with my home made target.  It has indeed damaged many UNI-T meters along with a few others.    :-DD   I imagine I could tone it down further if the goal is to get more meters to survive it but we wouldn't be able to compare results....
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 30, 2022, 09:20:00 pm
Just in case you're thinking about it, at my first job we had one of those tommy guns (keyence).  I knew a guy who wanted to look at the output of it and decided it was smart to zap the 10M scope probe.    We had one of those Tektronix huge mainframe DSOs with the external keyboards and a 100MHz plugin.   High end scope for it's day.   I didn't get to see it happen but in a small company, word travels fast.   Don't be that guy!  :-DD

****
Something like this old relic:
https://www.ebay.com/itm/133826840305?epid=96961633&hash=item1f28b386f1:g:cWUAAOSwNpFg-g2c&amdata=enc%3AAQAHAAAAwDpmdjpLrVZGGVtQ85eqNKRffOFpTXoVuHAYnQ5BHZtiSsDTYPxm88Pvs1fI0DXpt09My8XuFi2g%2FluXb%2FwEL%2FUxDsCFMlae8kr5aFC6MsDlWqR0ssDC%2FQlh8JXw2tiennHHqNwQFJMEtMIN0PrwS21oz%2Bsl5GpTpRGigAHqWIaKGDCnm9MAl0WrBgdJuovXW0AayyCVDsW2GoVAdE5aE3FlEKIAKdsdX33v5k2dTPl%2FhHOsK83LbMXb6kz0Fcwk6A%3D%3D%7Ctkp%3ABk9SR9jdhoreYA (https://www.ebay.com/itm/133826840305?epid=96961633&hash=item1f28b386f1:g:cWUAAOSwNpFg-g2c&amdata=enc%3AAQAHAAAAwDpmdjpLrVZGGVtQ85eqNKRffOFpTXoVuHAYnQ5BHZtiSsDTYPxm88Pvs1fI0DXpt09My8XuFi2g%2FluXb%2FwEL%2FUxDsCFMlae8kr5aFC6MsDlWqR0ssDC%2FQlh8JXw2tiennHHqNwQFJMEtMIN0PrwS21oz%2Bsl5GpTpRGigAHqWIaKGDCnm9MAl0WrBgdJuovXW0AayyCVDsW2GoVAdE5aE3FlEKIAKdsdX33v5k2dTPl%2FhHOsK83LbMXb6kz0Fcwk6A%3D%3D%7Ctkp%3ABk9SR9jdhoreYA)
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 31, 2022, 02:54:17 am
But now I think we get to the crooks of what you are driving at. 

"crux"  :popcorn:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 03:08:36 am
 :-DD :-DD :-DD
****
Quote
............ the crooks of what you are driving at.  You suspect the grill start is putting out ...
 

Also, stater.  Guessing many others... Dig deeper.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 31, 2022, 03:16:46 am
:-DD :-DD :-DD

Just keeping things on the straightened arrow...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 03:21:08 am
Nice.  I've been known to use such poor spelling/grammar that I couldn't even make sense of it the following day.  Worse, I have no drug problems to blame it on.    :-DD   
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 31, 2022, 05:20:28 am
A megavolt? Not hardly. That would allow for a spark across a gap of a metre, never mind a meter! As I said, maybe 10kV.

What I was curious about is whether the the output of these things is too fast for the protection circuitry to react to, as it is obviously going to be way lower energy than the IEC standard tests for CAT ratings, and less than the 20J your transient generator puts out. My point therefore is, given these facts, how does it damage (for example Uni-T) meters? My only guess is it's too fast for the clamp(s).
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 12:58:57 pm
A megavolt? Not hardly. That would allow for a spark across a gap of a metre, never mind a meter!

Quote
You suspect the grill start is putting out 1MegaVolt which unfairly wipes out all of those UNI-T meters.    :-DD
I didn't expect you to read that as a literal statement but ok.

As I said, maybe 10kV.

As I wrote: 
Quote
If we use 1000V per mm, 10mm air gap for 10kV, I have no doubt that I have one grill starter that will exceed that. 
  Maybe the post was too long for you.

What I was curious about is whether the the output of these things is too fast for the protection circuitry to react to, as it is obviously going to be way lower energy than the IEC standard tests for CAT ratings, and less than the 20J your transient generator puts out. My point therefore is, given these facts, how does it damage (for example Uni-T) meters? My only guess is it's too fast for the clamp(s).[/color][/size][/b]

You seem confused.  You start out asking about ESD then you switch to CAT ratings and 20J.   ESD has nothing to do with CAT ratings.  It is called out in IEC 61326, not 61010.   

The small 20J transient generator I show has a 1.2us risetime as can be seen in the scope shot above.   This is something I took from the IEC standards which I based my generator on.   

Yes, I could tone down every test I run.  Maybe chemical test with tap water, drop them from 1mm, ESD test them with my finger while wearing a wrist strap....   

No doubt I could just unbox the meters, blab for a half hour telling people how great the products are and then give them 5 stars.  Finish up with Don't forget to like and subscribe.  Consider supporting me on patreon so I can continue to bring you this great content. 

That's not something I have any interest in.  I do like seeing how the different brands hold up against one another.   The fact some brands are more sensitive and prone to failures than other under certain conditions is pretty much the whole point of this thread.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 03:07:49 pm
I did write Dave about the U1282A that he swam with, drove over, tossed off the bridge, threw against the wall to see if he would be willing to part with the PCB to possibly salvage this meter.  Maybe we will get lucky.

Until then, it's time for the next phase.
Title: Re: Handheld meter robustness testing
Post by: AVGresponding on August 31, 2022, 04:03:58 pm
I am not confused, I never mentioned ESD, that was Fungus and latterly yourself. I am asking a question. What does the transient generated by a grill starter look like across the inputs of a DMM?
You partially answered me by pointing out that piezo spark generators are very inconsistent in their output; fine, thank you for that information.

I then asked why the grill starter damages meters; is the transient too fast for the clamp, or is it something else? I mentioned CAT ratings and your transient generator merely to compare the energy levels involved.

I am asking for your considered opinion, or if you know the answer, that is all. I am not asking you to perform any additional tests.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 04:58:59 pm
I am not confused, I never mentioned ESD, that was Fungus and latterly yourself. I am asking a question. What does the transient generated by a grill starter look like across the inputs of a DMM?
You partially answered me by pointing out that piezo spark generators are very inconsistent in their output; fine, thank you for that information.

I then asked why the grill starter damages meters; is the transient too fast for the clamp, or is it something else? I mentioned CAT ratings and your transient generator merely to compare the energy levels involved.

I am asking for your considered opinion, or if you know the answer, that is all. I am not asking you to perform any additional tests.


To be clear from the context of the tests I show,  Grill starter = ESD != 20J.   In simple terms, the grill starter damages meters (mostly UNI-T) as they are not very robust.  Why each particular meter was damaged is far beyond the scope of this thread.   However,  I did do a more detailed analysis of the UT61E and talked about the UT181A and reasons why they were damaged.  These are not so much my opinion as I backed up my comments with data. 

For your question
Quote
What does the transient generated by a grill starter look like across the inputs of a DMM?
, I assume you want to look at the voltage rather than the current.   While I did show this from the UT61E's controller IC's perspective, it is not what you asked.  Again, I would expect this to be different with each meter.    I don't have a good way to look at it.   It suspect it far exceeds any probe I have.   

If you are interested in trying to measure it yourself with a few different meters and grill starters.  I am interested in seeing your results.     Just be aware of my friend who damaged that DSO attempting to do something similar.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 06:01:41 pm
Life cycle testing has begun.  How many cycles do you think the detent spring will last?  Cast your vote...

Plan is to let it run the full 50k as then sweep up what's left.
Title: Re: Handheld meter robustness testing
Post by: Fungus on August 31, 2022, 08:40:11 pm
Life cycle testing has begun.  How many cycles do you think the detent spring will last?  Cast your vote...

I say "no more clickys" at 1600.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 09:12:46 pm
Remember our friend who said they put 10's of thousands of cycles on the first Keysight I looked at every year.   He even made a video to prove it for us.  You don't believe??   :-DD :-DD

It only has about 5000 cycles on it so far and lets just say things don't look Sound good.   

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on August 31, 2022, 09:36:37 pm
A few links for the ESD enthusiasts:

https://www.eevblog.com/forum/metrology/measuring-esd-on-an-osilloscope/ (https://www.eevblog.com/forum/metrology/measuring-esd-on-an-osilloscope/)

https://download.tek.com/document/Verifying_ESD_Simulator_Performance_Using_an_Oscilloscope_App_Note_48W-73760-0.pdf (https://download.tek.com/document/Verifying_ESD_Simulator_Performance_Using_an_Oscilloscope_App_Note_48W-73760-0.pdf)
https://www.edn.com/proper-oscilloscope-setup-yields-correct-esd-measurements/ (https://www.edn.com/proper-oscilloscope-setup-yields-correct-esd-measurements/)
https://www.onsemi.com/pub/collateral/and8307-d.pdf (https://www.onsemi.com/pub/collateral/and8307-d.pdf)
Title: Re: Handheld meter robustness testing
Post by: tautech on August 31, 2022, 09:55:03 pm
It only has about 5000 cycles on it so far and lets just say things don't look Sound good.
Oh, covers mouth with hand !  :scared:
 :popcorn:
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 01, 2022, 12:57:15 am
Sorry you Keysight fanboys.   I am unable to continue the 50,000 cycle life test.   I left a clue in the photo for you.   

Considering I even put that last UNI-T meter through this same test, seeing two Keysight meters do so poorly with this test is just one more disappointment to add to the list.   It's not a free meter from Harbor Freight. 
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 01, 2022, 03:54:18 am
I did write Dave about the U1282A that he swam with, drove over, tossed off the bridge, threw against the wall to see if he would be willing to part with the PCB to possibly salvage this meter.  Maybe we will get lucky.

Doesn't seem much point any more...
Title: Re: Handheld meter robustness testing
Post by: GuidoK on September 01, 2022, 08:56:55 am
Sorry you Keysight fanboys.   I am unable to continue the 50,000 cycle life test.   I left a clue in the photo for you.   

But you are making a video about it...right?  ;D

BTW, I was wondering about the grill starter test.
In the video's it's not very visible, but I think you hold the end of the grill starter physically to the multimeter input terminal, right?
Does it make a difference when you don't do that and let it hoover slightly above that input terminal (say 1mm or so) and when you press the button, there is a spark over that airgap?
Won't that ramp up the voltage considerably? (because of the extra resistance of the air gap)
Or is the total path of resistance then so high (airgap plus resistance in the meter itself) that no spark is even happening?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 01, 2022, 12:21:42 pm
But you are making a video about it...right?  ;D
Yes 

BTW, I was wondering about the grill starter test.
In the video's it's not very visible, but I think you hold the end of the grill starter physically to the multimeter input terminal, right?

Both ESD transients are direct contact.

Does it make a difference when you don't do that and let it hoover slightly above that input terminal (say 1mm or so) and when you press the button, there is a spark over that airgap?
Yes

Won't that ramp up the voltage considerably? (because of the extra resistance of the air gap)
Or is the total path of resistance then so high (airgap plus resistance in the meter itself) that no spark is even happening?

Maybe watch the following starting about 8:30.   
***
Note that this probe (and scope) would not have the bandwidth to actually look at these transients.  All I am doing in this video is trying to get some idea where the probe will breakdown.  When I looked at the grill starter with my homemade target, I used my old 5GHz LeCroy. 

https://www.youtube.com/watch?v=OUfWYwPB9uI (https://www.youtube.com/watch?v=OUfWYwPB9uI)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 01, 2022, 03:29:12 pm
Towards the very end of this video, I show an old spark plug that uses two different gaps.  One adjustable, one fixed that ignites the mixture.   The adjustable one also can be closed up.   As we increase this secondary gap, we increase where it will breakdown and increase the current through the second gap.  In my youth, I would do this manually by lifting the boot to clear out a fowled plug on my 2-stroke bikes.

https://www.youtube.com/watch?v=kWOe803atvg (https://www.youtube.com/watch?v=kWOe803atvg)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 03, 2022, 06:49:26 pm
Dog4 watching while I drag out scopezilla to have a look at whats left of the Keysight meter.    Plan to wrap things up today. 

Dog4 has been with us almost 2 years now after the original owner had abandoned her at a kill shelter.  She gets a lot of exorcise and her overall health has improved.    Her eyesight was starting to fail and we discovered she has Pannus which is an autoimmune disease.   It's nothing I have ever heard of and to me, it looks like a cataract. 
Its more common in certain breads like German Shepherds.  If caught early enough the effect can be reversed.   Left untreated.....   She will have eye drops the remainder of her life and it is clearing up.   Something to be aware of.
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 03, 2022, 06:59:07 pm
Dog4 has been with us almost 2 years now.  She gets a lot of exorcise

Demonic dog? You need to be very careful with those...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 03, 2022, 08:33:17 pm
exercise   :-DD  Still, she does have a bit of an evil streak about her.  Likes to take things from the lab while I am looking right at her.  Doesn't shew them but takes off running.  Then it's off for some play time.    :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 04, 2022, 11:57:19 am
Conclusion

https://www.youtube.com/watch?v=gPnSSJZwdIk (https://www.youtube.com/watch?v=gPnSSJZwdIk)
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 04, 2022, 04:42:44 pm
Thanks for showing the stepper motor setup in detail.

Do you adjust the maximum motor torque for each test based on the force required to turn the dial?

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 04, 2022, 05:52:11 pm
Thanks for showing the stepper motor setup in detail.

Do you adjust the maximum motor torque for each test based on the force required to turn the dial?

Wait, nothing about rubust and shews??   :-DD   

Yes.  If you watch the following video, starting around 6min in or so, I go over the cycle test in more detail.   When you watch the Keysight U1282A, note that when the software initially tries to move the motor, the current is already too low and it stalls right away.  The Keysight meter has a lot more drag than the Brymen shown.  When I set the starting current where I start to look for the stall, this is the first time it was not high enough to get the switch to rotate.   The motor can produce more torque but nothing like I can with my hand..   

You may remember my posting about loaning out a meter and the person turning the knob past the dead stop and breaking the plastic.   That was a cheap CEM.  I could see something similar happening to this meter once the drag gets so high.  I suspect many users will try to force it.  If that doesn't work, the hammer is next.   

Good job Keysight!!
Over spec the frequency input  (Defpom claims they are changing the paper work to address this)
Data logging that glitches
Lettering that comes off easily
Poor input protection that not only allows damage to the meter at fairly low voltages, but does not protect the sensitive ICs that can not be replaced (can you say disposable)
A function switch that can't survive even a fifth of what the better class of meters can handle

I guess it's water tight so if you want to go swimming with it, you're good to go!    :-DD

https://www.youtube.com/watch?v=bs5n3a__Yq0&list=PLZSS2ajxhiQBK3lIiozNmw2TfLVCG1Rxu&index=6 (https://www.youtube.com/watch?v=bs5n3a__Yq0&list=PLZSS2ajxhiQBK3lIiozNmw2TfLVCG1Rxu&index=6)
Title: Re: Handheld meter robustness testing
Post by: gnavigator1007 on September 04, 2022, 06:02:19 pm
Good job Keysight!!
Over spec the frequency input  (Defpom claims they are changing the paper work to address this)
Data logging that glitches
Lettering that comes off easily
Poor input protection that not only will damage the meter at fairly low voltages, but does not protect the sensitive ICs that can not be replaced
A function switch that can't survive even a fifth of what the better class of meters can handle

It even says right on the box:
Retool Your Expectations

 :-DD
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 04, 2022, 06:16:34 pm
 :-DD :-DD
Title: Re: Handheld meter robustness testing
Post by: Fungus on September 08, 2022, 05:21:55 pm
Will we see the new 2000V Uni-T be subjected to the grill starter?
Title: Re: Handheld meter robustness testing
Post by: GuidoK on September 08, 2022, 05:46:09 pm
I was wondering:
Have you ever cycle tested the rotary switch on one of the smaller Brymen meters?
I couldn't find anything about that.
I believe you have the BM235 and BM319 that fall in that form factor?
I saw both the BM869S and BM839 cycle tested, and results were similar after 50k cycles, and I guess that makes sense as they're situated in virtually the same housing and the switch also looks virtually the same.
But the BM235 and BM319 have a smaller housing and maybe a differently sized switch? It would be interesting to see how those smaller meters performed in the switch cycle test.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 09, 2022, 11:41:27 am
I was wondering:
Have you ever cycle tested the rotary switch on one of the smaller Brymen meters? I couldn't find anything about that.

Assuming physical size,  I ran a BM786 which is physically much smaller than the BM869s.     

I believe you have the BM235 and BM319 that fall in that form factor?
I saw both the BM869S and BM839 cycle tested, and results were similar after 50k cycles, and I guess that makes sense as they're situated in virtually the same housing and the switch also looks virtually the same.
But the BM235 and BM319 have a smaller housing and maybe a differently sized switch? It would be interesting to see how those smaller meters performed in the switch cycle test.

I have not ran Dave's rebranded BM235 I bought from him.   We do know that Brymen does run a similar test on their products.   I've posted a few clips of their setup.   I think they actually had a similar meter on their jig in those clips.   
Title: Re: Handheld meter robustness testing
Post by: GuidoK on September 09, 2022, 12:28:51 pm
I've posted a few clips of their setup.   I think they actually had a similar meter on their jig in those clips.
Ok, but having a meter on their jig is not the same as showing the result of the test of course. BTW if I look at those clips from Brymen, to me it looks like a BM869s and some current clamp is shown, but the clips are not very clear and maybe I'm looking at the wrong clips. (I look at the clips you show in your BM869s life cycle video; funny enough the rotary switch from what I believe is a BM869s in the Brymen video doesn't sound very healty to me (the clicking), but in your test the indent spring had no wear whatsoever; but of course we don't know what was in that Brymen meter in the video from Brymen, they just as well might have been experimenting with glass fibre reinforced plastics for indent springs  ;D)

Looking at your video's, it looks like the switch of the small form factor meters like the BM235 and BM319 have quite a different construction to the BM869s or BM786, where the BM235/319 have the swipe contacts integrated in the part with the indent spring (which also looks to be somewhat different) and mated on the front housing part instead of a seperate construction piece that is screwed to the pcb.
I can't make a good size or construction comparison myself between the small and larger brymen meter rotary switches, I look at your video's for that. I only have a BM869s, and don't own a BM235 or other meter in that small form factor.

The BM869s and BM786 look somewhat similar, but it looks the BM869s seems to have switch contacts on both sides and the BM786 not, but on both of those meters the swipe contacts are housed in a separate construction that is screwed to the pcb.

So I think a life cycle test on the BM235/319 rotary switch would still give interesting information due to the different construction. At least interesting for people that own a Brymen in that small form factor or plan to buy one.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 09, 2022, 11:42:29 pm
I wonder if Dave ever ran the BM235.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 11, 2022, 01:46:05 pm
I've shown my ESD targets (low inductance current shunts) and how I mounted the SMD resistors inside the two layers of PCB.   Here is a video explaining in more detail how to make some simple shunts. 

https://www.youtube.com/watch?v=DAsn1Yf44Ao (https://www.youtube.com/watch?v=DAsn1Yf44Ao)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 17, 2022, 02:43:10 pm
I've had a lot of people asking me about my transient generator.   Here you can see one of the forum members attempting to construct their own combo generator that follows the IEC standard.   The claim is they can reproduce the open circuit voltage and short circuit current waveforms with their prototype, which they show.   It may be of interest to a few of you.   

https://www.eevblog.com/forum/beginners/what-are-the-tricks-for-winding-a-tight-air-core-inductor/msg4356235/#msg4356235 (https://www.eevblog.com/forum/beginners/what-are-the-tricks-for-winding-a-tight-air-core-inductor/msg4356235/#msg4356235)
Title: Re: Handheld meter robustness testing
Post by: GuidoK on September 17, 2022, 04:59:49 pm
I was looking at some of your old video's, particularly about the Fluke 17B+, and I noticed a perculiar thing.
In the first review/testing of the Fluke 17B+, you made a remark about that the switch was so lubed up.
It also can be shown in this video @ 4:48:
https://youtu.be/wiiii0gdcbM?t=288 (https://youtu.be/wiiii0gdcbM?t=288)
You also commented about this in this post:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg809665/#msg809665 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg809665/#msg809665)

But when life cycle testing the rotary switch from the 17B+, you state that the switch contacts are dry.
In this video (about the life cycle testing) at 21:22 you show that it's the meter you repaired, showing parts that you've resoldered, but the switch of that meter is completely dry (as seen a moment later in the same video (at 22:15):
https://youtu.be/x_L6Z8BAXFQ?t=1282 (https://youtu.be/x_L6Z8BAXFQ?t=1282)

So my question is: what happened here? Is this the same meter that you used in the first test? And are Fluke 17B+ rotary switch contacts lubed or not?
I don't really understand what happened here, but it doesn't seem logical to me.
I searched in this thread but couldn't find a real explanation for this.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 17, 2022, 05:56:11 pm
So my question is: what happened here? Is this the same meter that you used in the first test? And are Fluke 17B+ rotary switch contacts lubed or not?
I don't really understand what happened here, but it doesn't seem logical to me.
I searched in this thread but couldn't find a real explanation for this.
It seems perfectly logical to me.   What happened?  I would say "time" happened.   From the first video dated Dec 2015, it was supplied with lubrication.   In that same video the meter had been damaged and I talk about ordering parts to repair it.   It doesn't appear I made a follow up video showing the repairs.  There's no magic disappearing grease.  I obviously cleaned the PCB when working on it.   

I'm guessing I had no plans to do anything more with the meter (as far as transient testing it again) and never reapplied grease to the contacts.  That or by the time the parts arrived, I had already cleaned the board when removing the part and just forgot to replace it.    Fast forward two years to Nov 2017,  when I started to look at life cycling switches and pulled this meter out of the box as fodder.   The contacts were still dry. 

Now of course, there may be some question on how the grease would have effected the life cycle test.  Oldly enough, this meter remains one of the best switches I have looked at running with dry contacts.  The 17B+ was damaged at a fairly low level compared with other Fluke products I looked at and I wonder if the leaving the grease off would have caused it to fail at an even lower level.   Hard to say.

Mystery solved.   Old hobbyist reviewing meters.    Great question BTW.  Good to see someone paying attention! 
Title: Re: Handheld meter robustness testing
Post by: Grandchuck on September 17, 2022, 08:49:51 pm
How about that!
Title: Re: Handheld meter robustness testing
Post by: arcitech on October 18, 2022, 03:06:15 pm
I think this could require big changes to a meter's front-end, but I'd love to see if the FLIR DM92/3 would "come-a-gutza" under your hands! At this level it competes with Fluke, so if we could get Flir to send you one, it would be nice to know if the switch can take a good beating too. I bet you'd knock it out with the grill starter and send them back to the drawing board  :-DD

For what it's worth, a US-based T&M shop has DM92 meters available at $179+shipping on eBay, and (not that it matters to Joe I'd suppose) has confirmed that their shop is an authorized FLIR distributor. It's a far cry from their (own) website's listing at $299. Maybe for this price, it's worth a shakedown..?

(I've avoided links and name of the shop in hopes of not jeopardizing authorized distributor standing; I certainly don't claim to know the rules, but would imagine those who do are likely under NDA, so I'll assume putting names/links on blast would be somewhat irresponsible.)
Title: Re: Handheld meter robustness testing
Post by: paulbt on November 21, 2022, 11:19:30 am
Hello!

I searched on this forum for "multimeter input protection", but I could not find anything related other than this topic.

I have a crappy Axiomet dmm with no input protection. I wanted to have some fun with it so I cut some traces and added in series with V/ohm input a 2W 1K resistor, a 1K PTC and a MOV back to COM input.

After this, voltage measurement is 'good' as before, but resistance measurement is affected by the added components. No surprise for me, when I short the leads I get ~2K reading.

I watched again Dave's video on this, but I could not understand how they manage to read the resistance correctly and to have overload protection at the same time.

Can anyone please explain it for me?

If you know any discussion about this on the forum, please post a link here.

Also, please see the attached pictures.



Title: Re: Handheld meter robustness testing
Post by: Chance92 on November 21, 2022, 12:07:34 pm
After this, voltage measurement is 'good' as before, but resistance measurement is affected by the added components. No surprise for me, when I short the leads I get ~2K reading.

I am not quite sure, but my guess is you need to recalibrate and adjust your multimeter to compensate the additional resistance of the additional components.
Title: Re: Handheld meter robustness testing
Post by: paulbt on November 21, 2022, 12:30:08 pm
After this, voltage measurement is 'good' as before, but resistance measurement is affected by the added components. No surprise for me, when I short the leads I get ~2K reading.

I am not quite sure, but my guess is you need to recalibrate and adjust your multimeter to compensate the additional resistance of the additional components.

I was thinking about calibration/relative/delta stuff, but this needs to be done way too often, that additional resistance is changing with ambient temperature or overload conditions.
Anyhow, I don't really care about my dmm, I will use it only for voltage measurements when needed, I have other safer dmm on my bench.
I just have an opportunity to learn something. Seems like Dave did not explain it. That's why I'm asking...how do they do it?
Title: Re: Handheld meter robustness testing
Post by: SeanB on November 21, 2022, 01:02:29 pm
The resistor and PTC has to be on the current feed line, not the voltage sense line, which is already protected by the resistors and the clamp transistors there. You need to move them so the voltage sense is at the input, not after the PTC. that way the extra resistance is not part of the resistance measurement, but just reduces the compliance voltage slightly in resistance mode, but the measurement is still accurate. Look on the Fluke input and you see there are 2 paths from the input jack, one is the current for the resistance range to use, along with continuity and capacitance, and also for the mV range, while the other path is used to read voltage on the jack in all those modes. you need to separate those and put the protection in the current path alone, the other one already has protection.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 21, 2022, 01:23:19 pm
I have a crappy Axiomet dmm with no input protection. I wanted to have some fun with it so I cut some traces and added in series with V/ohm input a 2W 1K resistor, a 1K PTC and a MOV back to COM input.

I've done this a few times.   My question is, how are you planning to validate your changes?  Lets assume what ever you come up with doesn't fuck up the measurements.  How are you planning to prove that your meter is now more robust or "safer" as you put it?   

If the only goal of chopping up the meter is for learning,  I suspect you would be better off playing on some breadboard and learning how a meter works.  From there you could learn how the protection circuits work.

Here's a whole series on my mods to low cost meter.   

Starting out
https://www.youtube.com/watch?v=OOpsHiiHtC0 (https://www.youtube.com/watch?v=OOpsHiiHtC0)

second attempt
https://www.youtube.com/watch?v=-V9JvFRjL78 (https://www.youtube.com/watch?v=-V9JvFRjL78)

14kV or bust
https://www.youtube.com/watch?v=dEwLuiYX5cQ (https://www.youtube.com/watch?v=dEwLuiYX5cQ)

Showing final mods
https://www.youtube.com/watch?v=EkQ6CCj7jmU (https://www.youtube.com/watch?v=EkQ6CCj7jmU)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 28, 2022, 12:43:57 am
Having fun with a very old NST and a few parts salvaged from damaged, non-repairable meters.    I have a 121GW that is in very rough condition along with that last Keysight meter that can't be repaired.... 

https://www.youtube.com/watch?v=Ssr1_sL_cTY (https://www.youtube.com/watch?v=Ssr1_sL_cTY)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 28, 2022, 01:30:42 pm
Some time ago Dave posted:
 
Quote
What happens when you apply five thousand volts across the range switch of a cheap ass multimeter?  I'm glad you asked

I wonder what happens when we apply 12kV across the range switch of a few expensive multimeters.   I have a couple of them that are beyond repair that we could use to help answer this question.

https://www.youtube.com/watch?v=sKcH4JxnxbQ (https://www.youtube.com/watch?v=sKcH4JxnxbQ)
https://www.youtube.com/watch?v=Ru2rb7bFhag (https://www.youtube.com/watch?v=Ru2rb7bFhag)



Title: Re: Handheld meter robustness testing
Post by: Fungus on November 28, 2022, 03:16:39 pm
Would the Fluke 101 take that for a couple of seconds?  :popcorn:

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 28, 2022, 05:54:25 pm
I'm not sure what this transformer puts out during startup.  Maybe start there and design a way to program the number of AC cycles.     Then again, I doubt many of us would try to directly measure such a transformer...   Oh wait, we have had people post about directly measuring their MOTs....  Never ends well. :-DD 
Title: Re: Handheld meter robustness testing
Post by: 2x2l on December 20, 2022, 06:48:32 am

It even says right on the box:
Retool Your Expectations

 :-DD
zing. but seriously, real talk - im absolutely devastated by how far HP fell. gender equality for all - carly fiornia proved that women can be as savage as men in business. she managed to take a marvelous, competent company (from the health sciences to VMS/nonstop banking mainframes -- and everywhere in between) and fracture it off in search of short-term profiteering and performance bonuses. i digress.

that being said, ebay a fluke 101, fluke 107 for $120ish shipped (wait for the price dips, the 101s are sub-50USD often).


hey joe, can you test the NGK low-emi plugs and see how meters respond to those HV EMPs? (i.e. the standard "meter resets", or what have you)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 20, 2022, 02:14:40 pm
hey joe, can you test the NGK low-emi plugs and see how meters respond to those HV EMPs? (i.e. the standard "meter resets", or what have you)

Depends what you are asking.  First, I am not sure what these low-EMP plugs are.  You should have provided a datasheet or at least a part number.   Plugs do not come in one size.  Depending on how you want to test them, my jig is for a 12mm thread / 1.25mm pitch.   I have a few different wires/boots/coils/ignitions that I can test with.   

I assume you are asking if your plugs would cause less meters to reset.  This may be very difficult to quantify.  Maybe a better test would be to look at the radiated emissions from it.   The problem with this is I am not sure how I would measure it.  The source is enough to knock out that crappy USB bus from 5 feet away or so.   

While you search for  data on the plugs you want tested,  consider that the wires I use are around 50ohms / foot. The plugs I show are >> 1k ohms.    You also need to consider that the emissions will be dependent on gap, pressure....   I have only tested with nitrogen. 

Give it some thought. 

***
If we were to look at meters rather than trying to measure the pulses directly, I would want you to narrow that down to maybe one or two meters. 
Title: Re: Handheld meter robustness testing
Post by: golftango on March 08, 2023, 09:25:40 pm
as i said in the main thread for this meter, i'm way way late to this party and just received mine yesterday. i got some other meters which should satisfy any needs for accuracy, but they are huge--the dimensions on paper don't begin to prepare you for the actual size. i freely admit i didn't shop this as rigorously as i usually do. i had already found a couple of great ebay deals on a fluke 289 and a hioki 4281 so i hardly needed another meter.

but those meters (esp the 289) are on the largish side and i wanted a more compact daily driver so i was shopping for a 4-1/2 digit 50k count small meter and optionally bt capability and the fluke 117 and the owon bt41 were only 6000 count and only the owon had bt. i had read and watched quite a few reviews praising eevblog and had recently joined the forum, so when i came across the 121 by accident with a good price and shipped from the usa i jumped on it without much more thought. only after i ordered it did i start seriously researching it.

but putting all that aside, i tend to really baby my electronics (i'm not the target market for your destruction derby videos for sure--but you had the most detailed info by far) and in the next couple of days i'm going to do my best to compare readings among the fluke, the hioki, and the eevblog and if the 121 is anywhere near the ballpark of those i'll be well satisfied. and the bt on the 121 means i won't have to depend on the fluke internal logging since it has no way of connecting to mac or ios even with the expensive and touchy accessory. /guy

and let me say i have no need for a really good meter--i have a $40 fluke 101 and a hioki 'card' meter both of which, combined with an outlet tester or a clamp meter, would meet most of my needs. but again, i'm a gadget collector and a ham so i appreciate nice sturdy accurate devices.

at any rate, i'm one of those nerds who reads every scrap of documentation, and with the advent of youtube, try to find the patience to sit through videos although i'm not much of a visual learner. and compared with other devices there's not that many videos on the 121gw and, (ass)uming you're the joe smith on youtube, your videos are by far the most detailed of all.

i've now watched through part 6 and learned to avoid methanol (!) and noted in your summary around 56:20 that you say (paraphrased): 'personally, i think this meter has way too many problems to be considered anything more than a gimmick. i think the real selling point is this logo (circles the eevblog logo) and if you look beyond that (something about a ?grill starter? (which i never understood what it was when you demo'd it)) ... you have to believe that uei could do a better job ... and this meter is not that robust'.

my meter came with fw v1.22 which i updated to v2.05 first thing. next i checked the bt using the ios meteor app and that process was seamless and the app works well. i have some modest components i'm going to use for reference coming in and then i plan to compare the 121 against a couple of those supposedly more accurate meters.

so i guess my question is, how can i tell if the particular sample i have has had some or all of the problems you observed corrected? since it came with v1.22 i don't have much hope though. and thanks for the videos even though about 75% of your tests i'll never have to worry about unless there's an electronics apocalypse in the future or i end up going to a ham radio field day! :)

/guy
Title: Re: Handheld meter robustness testing
Post by: golftango on March 08, 2023, 09:38:12 pm
also, i i noticed a couple of posts earlier you replied to someone: "im absolutely devastated by how far HP fell. gender equality for all - carly fiornia proved that women can be as savage as men in business. she managed to take a marvelous, competent company (from the health sciences to VMS/nonstop banking mainframes -- and everywhere in between) and fracture it off in search of short-term profiteering and performance bonuses. i digress."

i 1000% agree with this! i was a radioman in the navy from 1970-1980 and you couldn't fling a frog without hitting hp test equipment. about the only other ubiquitous brand was the simpson analog vom. we had an hp cesium beam clock at the satellite earth station i worked at in australia and hp would calibrate those in oregon and buy a plane ticket for it and the tech who hand delivered it. they cost like hundreds of thousands of dollars but were required in order to calculate the doppler shift back in the pre-geosynchronous days when the 'birds' really 'flew'. :)


i learned programming with the hp-55 calculator and on the carrier cic dept they used the hp-97 (?) with the card reader to match up sonar 'fingerprints' to subs and surface shipping. hp was at the pinnacle of tech and there's a reason jobs and wozniak worked there. sadly, in the 80s they wouldn't have wanted to say they ever worked there. first they started making their calculators in malaysia and thailand and singapore and at the time we thought they'd totally gone to shit. but let me tell you that i have quite a few of those calculators which are now 40-60 years old and despite us thinking them shit back then, they far surpass anything being built today.

oh well, i could go on forever, but it was heartbreaking to see such a famous company go tits up.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 09, 2023, 03:23:50 am
...
so i guess my question is, how can i tell if the particular sample i have has had some or all of the problems you observed corrected? since it came with v1.22 i don't have much hope though. and thanks for the videos even though about 75% of your tests i'll never have to worry about unless there's an electronics apocalypse in the future or i end up going to a ham radio field day! :)

/guy

Guy,

I saw your comment on YT and decided to check in.   Yes, I have dialed back my usage of this site as most of the posts now pertain to topics (religion, politics, race)  that I have no interest in reading.   Looks like the pictures are again screwed up as well.   Sad.

To your question, I would start by asking yourself is what I showed even important to you.  I knew of most of the problems with the 121GW before it was released.  I waited a full two years after its release before I reviewed the meter just to give them the benefit of the doubt.   Most of what I saw in the released product was what I had uncovered with the prototype during my initial testing.   I think most of us knew switch wear would be a factor as  people had posted various design changes.   There have also been several posts of owners having problems with the switch. Cracking plastic has also been an on-going problem.  I believe two of mine now have cracks.   So it seems if you recently purchased one, you would have had an idea of what you were getting as far as quality and there shouldn't be any surprises.   

You could easily check the switch for example.  I provided the board thickness of mine.   Just use your eyes and see if it uses a shim.  What do the contacts look like.   Firmware wise, I gave up following when it became apparent that wasn't something in their wheelhouse.    Maybe it's the greatest product out there now.  I really have not been following it, nor do I use the one that I used for my non-destructive tests.   

I did write some software for the BLE and once I sorted out my mistakes, it seemed to do a reasonable job.  I don't know if they ever did provide more details in the manual about using the meter to measure power.   I did walk KainkaLabs (youtuber) through the problem and how to work around them.  They made a video about it if  your are interested. 

Guessing your quote about Carly was not mine as it does not look like something I would write.  Basically I could care less if Carley is female, what her skin color is, what her religious beliefs are...  What I do care about is what people bring to the table.  This gets back to what I stated above.  As this site does seem more and more interested in such matters, where I came here for more technical discussions related to electronics.     

Anyway, enjoy your new meter.  There is a lot of information published about it so take advantage of the search engines.   Later
Title: Re: Handheld meter robustness testing
Post by: golftango on March 09, 2023, 03:29:52 am
thanks for the response. and indeed, i did get confused on the quote as it was by someone replying to you. i apologize. many thanks for taking the time to reply in detail and i appreciate every tip and point you made. /guy
Title: Re: Handheld meter robustness testing
Post by: EEVblog on March 11, 2023, 04:48:33 am
I saw your comment on YT and decided to check in.   Yes, I have dialed back my usage of this site as most of the posts now pertain to topics (religion, politics, race)  that I have no interest in reading.   

Not true. But you do know there are Topic, Thread and even Board Ignore lists, right?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 11, 2023, 05:45:28 pm
I saw your comment on YT and decided to check in.   Yes, I have dialed back my usage of this site as most of the posts now pertain to topics (religion, politics, race)  that I have no interest in reading.   

Not true. But you do know there are Topic, Thread and even Board Ignore lists, right?

Sorry, not true?  I assume you are referring to my comment of religion, politics... and not that I dialed back my use of the site or that I had seen the OPs comments.   You may have taken that to mean these three specific topics which wasn't my intent.  This is why I had closed with:

Quote
...  where I came here for more technical discussions related to electronics.

It's not what topics are being discussed,  rather it's whats missing.  Filters are not going to improve that.  Anyway, hope this clears things up. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 11, 2023, 06:34:28 pm
Thinking of this thread and non related topics,  I had a discussion a few days ago (pinned comment on attached video).   The FAQ cut down on much of the questions and it's been a while since someone wanted to troll the channel.  Normally, I wouldn't think anything of it but what's interesting is they post "... as a college instructor of electrical engineering, ...".   The context is great.   After a quick search, I believe this is true.   :-DD   

Did you attend any higher education?  If so what were your teachers like?  It appears here in the USA, the requirements for working in education change state by state. 

https://youtu.be/zzQ57h2vGV0
Title: Re: Handheld meter robustness testing
Post by: golftango on March 11, 2023, 07:11:15 pm
Thinking of this thread and non related topics,  I had a discussion a few days ago (pinned comment on attached video).   The FAQ cut down on much of the questions and it's been a while since someone wanted to troll the channel.  Normally, I wouldn't think anything of it but what's interesting is they post "... as a college instructor of electrical engineering, ...".   The context is great.   After a quick search, I believe this is true.   :-DD   

Did you attend any higher education?  If so what were your teachers like?  It appears here in the USA, the requirements for working in education change state by state. 

https://youtu.be/zzQ57h2vGV0

am i missing something? youtube in chrome only shows 4 comments although it says there are 23 of them and there are about 25 /likes/. at first i thought they might be counting replies, but that's not the case. in any event, i don't see the comment you reference.

as to your question about higher education, were you addressing that to someone or seeking responses from anyone? if the latter, i'm glad to supply one, but it's staggeringly long (tl:dr territory!)

/guy
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 11, 2023, 08:56:32 pm
am i missing something? ...

 :-DD  Yes, but it's because the OP pulled their comment which deleted the entire chain.  This isn't uncommon for trolls.  I expect most of them are aware World Wide Web means just that and once you post something up on social media, it's there for good.   See attached.   

as to your question about higher education, were you addressing that to someone or seeking responses from anyone? if the latter, i'm glad to supply one, but it's staggeringly long (tl:dr territory!)

/guy
Based on the OP's grammar and attempt to troll the channel,  I wouldn't have guessed they were involved in education outside of maybe attending high school.    A quick search seemed to show otherwise.  This had me wondering what are the requirements for various states when we look beyond the high school level.  A bit of an eye opener.   

My questions were directed towards anyone with a higher education.   Military, university (all colleges call themselves that but you know what I mean), community college, anything goes.  I bet there are some good stories out there. 

Thinking back, I had some really good teachers.  They were all very professional and many came from the industries they taught in.   I had made an attempt to contact one of them several years later just to thank them but sadly they had passed away. 
Title: Re: Handheld meter robustness testing
Post by: golftango on March 11, 2023, 10:03:28 pm
am i missing something? ...

 :-DD  Yes, but it's because the OP pulled their comment which deleted the entire chain.  This isn't uncommon for trolls.  I expect most of them are aware World Wide Web means just that and once you post something up on social media, it's there for good.   See attached.   

as to your question about higher education, were you addressing that to someone or seeking responses from anyone? if the latter, i'm glad to supply one, but it's staggeringly long (tl:dr territory!)

/guy
Based on the OP's grammar and attempt to troll the channel,  I wouldn't have guessed they were involved in education outside of maybe attending high school.    A quick search seemed to show otherwise.  This had me wondering what are the requirements for various states when we look beyond the high school level.  A bit of an eye opener.   

My questions were directed towards anyone with a higher education.   Military, university (all colleges call themselves that but you know what I mean), community college, anything goes.  I bet there are some good stories out there. 

Thinking back, I had some really good teachers.  They were all very professional and many came from the industries they taught in.   I had made an attempt to contact one of them several years later just to thank them but sadly they had passed away.

well, i'm outside your target group as i have zero higher education. but i think my story might show the effects of _not_ having it. sorry it's so long, but i try to put in all the pertinent details:

i realized in middle school that i detested being fed bits that someone thought comprised a suitable education. worse, even in the subjects i liked and was willing to try my best in such as literature and history, the pacing was way too slow and i'd end up racing through the textbook and library books on the subject and then being bored for the rest of the school year.

in high school i did find vocational photography and journalism worth the effort, but not worth sitting through nearly all the other classes. and in fact i was still pursuing a photography or journalism job more than a decade later when i got out of the navy which i joined on my 17th birthday---the fastest date i could drop out of high school. when i finished 2nd in my company of 75 on the basic induction tests i confirmed i had at least absorbed enough, on my own or in school, to hold my own. i passed the ged so quickly they wouldn't issue me the certificate until a year or two after i was supposed to have graduated.

but besides photography and writing i've been interested in tech and got my first ham license when i was 16 i think. when i joined the navy i wanted photographer or journalist but due to my scores on tech stuff the navy, in a rare spurt of common sense, made me a radioman and i didn't hate it--it just meant i'd take the navy photography and journalism courses by correspondence instead of a naval school.

i did well in the navy despite my detestation of authority and rote commands and routines and in fact they kept promoting me against my wishes as i have zero leadership qualities. i got the very first satellite class the navy offered in 1971--so new there weren't any navy instructors yet.

i made a huge mistake in leaving the navy after 10 years--8 years and six months short of retirement. but they were promoting me way beyond my leadership capabilities (peter principle anyone?) and at one point put me on an aircraft carrier and froze me there for nearly 3 years where i worked about 18 hours a day on average.

when i got out of the navy i headed to our local newspaper to try to get a job but they lied to me by saying that they wouldn't hire anyone without a degree. but the computer manager caught me (literally) in the parking lot with my car door open and hired me on the spot. and again, i didn't hate it as i had programmed calculators and built the very first pc (altair 8800) from a kit. and this was a hugely lucky event in my working life as i was getting in on the ground floor of the technological and telecommunications revolution. plus, as a huge bonus, i spent about 40-60% of my working time while the computers were processing back in the photo department helping them process film and even going out to shoot upon occasion.

i realize i've digressed significantly (i digress, i breathe) but all that was to point out that i had landed a very good job without any higher education and when i left there 13 years later telecommunications had taken off like a rocket and with my ham and navy communications and computer experience, i took off like a rocket as well and worked for nearly all the major telecom companies ending up at the largest computer services company in the world doing network analysis and all of it without a bit of 'traditional' higher education if you don't count tech schools. i realize that the computer tsunami wave i rode likely made me an outlier though--not sure anyone could achieve that if they started today where the babies have ethernet ports in their cradles. :)

/guy
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 11, 2023, 11:50:32 pm
Thanks for taking the time to post guy and thank you for your service.    I would say that your military training certainly counts for higher education.   Actually, let me say that I worked with a few good friends that had no formal education outside of what they learned in the military and they were sharper than many I knew that had their degree. 
Title: Re: Handheld meter robustness testing
Post by: EEVblog on March 12, 2023, 06:46:32 am
I saw your comment on YT and decided to check in.   Yes, I have dialed back my usage of this site as most of the posts now pertain to topics (religion, politics, race)  that I have no interest in reading.   

Not true. But you do know there are Topic, Thread and even Board Ignore lists, right?

Sorry, not true?  I assume you are referring to my comment of religion, politics... and not that I dialed back my use of the site or that I had seen the OPs comments.   You may have taken that to mean these three specific topics which wasn't my intent.  This is why I had closed with:

Quote
...  where I came here for more technical discussions related to electronics.
It's not what topics are being discussed,  rather it's whats missing.  Filters are not going to improve that.  Anyway, hope this clears things up.

You are not correct that when you said "as most of the posts now pertain to topics (religion, politics, race)"
That's simply not true.
Here is a list of the most recent topics as I post this, zero of what you mention.
Yes there is odd topic here are there that might drift into that, but practically all of the forum is electronics related in some way.
If you don't think there are any good electronics topics that interest you, then ok, each to their own, but don't blame it on "religion, politics, race topics".
Start a thread on a technical topic that interests you and watch people join in.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 13, 2023, 12:31:47 am
I saw your comment on YT and decided to check in.   Yes, I have dialed back my usage of this site as most of the posts now pertain to topics (religion, politics, race)  that I have no interest in reading.   

Not true. But you do know there are Topic, Thread and even Board Ignore lists, right?

Sorry, not true?  I assume you are referring to my comment of religion, politics... and not that I dialed back my use of the site or that I had seen the OPs comments.   You may have taken that to mean these three specific topics which wasn't my intent.  This is why I had closed with:

Quote
...  where I came here for more technical discussions related to electronics.
It's not what topics are being discussed,  rather it's whats missing.  Filters are not going to improve that.  Anyway, hope this clears things up. [/b]

You are not correct that when you said "as most of the posts now pertain to topics (religion, politics, race)"
That's simply not true.
Here is a list of the most recent topics as I post this, zero of what you mention.
Yes there is odd topic here are there that might drift into that, but practically all of the forum is electronics related in some way.
If you don't think there are any good electronics topics that interest you, then ok, each to their own, but don't blame it on "religion, politics, race topics".
Start a thread on a technical topic that interests you and watch people join in.

I guess my response still left you with some confusion of my intent of that statement.  No matter.   It won't change my lack of interest in the topics being discussed and my use of the forum will most likely continue to decline as a result.  It's not a big deal.   I was merely answering the OPs question about my apparent absence.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on April 23, 2023, 09:11:14 pm
My response to fungus's questions about the free Harbor Freight meters. 

Those free meters have gone through several hardware changes over the years to reduce cost.  Even if we saw a difference between the two meters I show, I couldn't tell you if it had anything to do with the label or not. 

Is 1100V the limit? Seems to me like a 2000 count meter should be able to display 2000V...  :popcorn:

Original posts may be found here:
https://www.eevblog.com/forum/testgear/trashy-meters-redux/msg4817894/#msg4817894 (https://www.eevblog.com/forum/testgear/trashy-meters-redux/msg4817894/#msg4817894)

https://www.youtube.com/watch?v=-ERyCsQ8tlA (https://www.youtube.com/watch?v=-ERyCsQ8tlA)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 26, 2023, 12:12:22 pm
Maybe it's worth the time to look at.  At least they don't claim the counter can read 200MHz this time!

https://www.youtube.com/watch?v=M43zqQp0rYM (https://www.youtube.com/watch?v=M43zqQp0rYM)
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on June 26, 2023, 12:43:56 pm
This time they are just claiming that Bluetooth will work through a closed ebox and a heavy steel door. Lol.

From their video it looked neat, then I looked at the specs. 0.3% 60000 count meter for $140. WTF
Title: Re: Handheld meter robustness testing
Post by: Grandchuck on June 26, 2023, 12:56:52 pm
About $110: https://www.aliexpress.us/item/3256805466430596.html?spm=a2g0o.productlist.main.5.48385619g9zuNa&algo_pvid=3b398086-d824-47a4-8d7d-ec0838872b5f&aem_p4p_detail=2023062605551514660048629148000000567842&algo_exp_id=3b398086-d824-47a4-8d7d-ec0838872b5f-2&pdp_npi=3%40dis%21USD%21213.32%21108.79%21%21%21%21%21%40211bea7b16877841157241682d07d7%2112000033895704502%21sea%21US%214108842368&curPageLogUid=ehSqclrOkexN&search_p4p_id=2023062605551514660048629148000000567842_3 (https://www.aliexpress.us/item/3256805466430596.html?spm=a2g0o.productlist.main.5.48385619g9zuNa&algo_pvid=3b398086-d824-47a4-8d7d-ec0838872b5f&aem_p4p_detail=2023062605551514660048629148000000567842&algo_exp_id=3b398086-d824-47a4-8d7d-ec0838872b5f-2&pdp_npi=3%40dis%21USD%21213.32%21108.79%21%21%21%21%21%40211bea7b16877841157241682d07d7%2112000033895704502%21sea%21US%214108842368&curPageLogUid=ehSqclrOkexN&search_p4p_id=2023062605551514660048629148000000567842_3)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 26, 2023, 01:11:44 pm
From their video it looked neat, then I looked at the specs. 0.3% 60000 count meter for $140. WTF

Well the ad does state "high precision" not great accuracy.   Still, is 60000 counts really high precision.  I think that Gossen I have is 300000 count and the Brymen BM869s supports 500000 counts in a few modes. 

I wonder what that PCB is that they show.  It looks like some sort of meter with the large shunt and HRC fuse.  Maybe a development tool for firmware.   

Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on June 27, 2023, 04:12:28 am
From their video it looked neat, then I looked at the specs. 0.3% 60000 count meter for $140. WTF

Well the ad does state "high precision" not great accuracy.   Still, is 60000 counts really high precision.  I think that Gossen I have is 300000 count and the Brymen BM869s supports 500000 counts in a few modes. 

I wonder what that PCB is that they show.  It looks like some sort of meter with the large shunt and HRC fuse.  Maybe a development tool for firmware.

I wonder if that's not a dev board for the meter? Same number of input jacks populated, close on the buttons.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 27, 2023, 04:24:07 am
Very possible.
Title: Re: Handheld meter robustness testing
Post by: glarsson on June 27, 2023, 08:33:06 am
I wonder if that's not a dev board for the meter? Same number of input jacks populated, close on the buttons.
The display has too few digits. The board must be for a different meter.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on June 27, 2023, 10:30:50 am
Interesting to see how Uni-T is targeting Fluke's 117 meter and its form factor. For about half the price you can get an interesting electrician's kit with clamp and magnetic hanger accessories. At this market, though, electrical and mechanical robustness are kings as well as track record, but for the latter there is nothing that can be done at this time. For the other two, Joe to the rescue!  ;D

It would be an interesting test indeed, but it is quite an investment.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on June 27, 2023, 03:31:25 pm
At this market, though, electrical and mechanical robustness are kings as well as track record, but for the latter there is nothing that can be done at this time.

I had just posted a comment to kissanalog on their best pick of an electrician's meter and basically repeated your comment.   :-DD
Title: Re: Handheld meter robustness testing
Post by: Chance92 on July 07, 2023, 11:13:26 am
Found a teardown of the UNI-T UT117C (in Chinese):
https://www.mydigit.cn/thread-401149-1-1.html (https://www.mydigit.cn/thread-401149-1-1.html)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 07, 2023, 11:47:13 am
Once again, single PTC with nothing else to limit the current.  With what they are starting cost now, I'm surprised they aren't using proven designs.   They look to be about the same package as the parts that came in the 61E+. 
Title: Re: Handheld meter robustness testing
Post by: Chance92 on July 07, 2023, 12:23:54 pm
Once again, single PTC with nothing else to limit the current.  With what they are starting cost now, I'm surprised they aren't using proven designs.   They look to be about the same package as the parts that came in the 61E+.

Do you mean it lacks a surge resistor?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 07, 2023, 02:31:03 pm
That would be common.   Still, even if they had added some other limiting device,  they would need to make sure they didn't fuck up anything else.  Tall order for UNI-T.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on July 07, 2023, 02:39:56 pm
Once again, single PTC with nothing else to limit the current.  With what they are starting cost now, I'm surprised they aren't using proven designs.   They look to be about the same package as the parts that came in the 61E+.
Well, in all fairness it seems they might be learning a thing or two from your previous failure analysis. If my eyes are not failing me, the HV path seems to have a pair of PTCs, two pairs of clamping transistors and a larger resistor R57 they think might hold back a serious surge.

However, it is a hefty price for a somewhat basic Uni-T.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 07, 2023, 04:20:51 pm
"product accuracy can still be guaranteed after a 2-meter drop"  :popcorn:

https://meters.uni-trend.com/product/ut117c/#Specifications
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 07, 2023, 05:23:22 pm
Once again, single PTC with nothing else to limit the current.  With what they are starting cost now, I'm surprised they aren't using proven designs.   They look to be about the same package as the parts that came in the 61E+.
Well, in all fairness it seems they might be learning a thing or two from your previous failure analysis. If my eyes are not failing me, the HV path seems to have a pair of PTCs, two pairs of clamping transistors and a larger resistor R57 they think might hold back a serious surge.

However, it is a hefty price for a somewhat basic Uni-T.

Assume R67.  I would need to trace it out.    Normally you would basically have two MOVs in series (shared on the return leg).   Ignore the second leg for now, you end up with one PTC in series with a MOV.  Say the MOV is 1kV.   If I apply 2kV, thats 1kV across the PTC.  Maybe it can handle it.  Those stupid piss ant 5mm parts they use in the cheap meters come apart and arc over.  Then there is nothing to limit the current.  In this case, let's say we have that SMT resistor in series with the clamp.  The clamp is basically a 0V and the 1kV is now across that resistor.  Maybe it survives.   Does it at 6kV?   :-DD    I like the tried and proven methods some of these companies have adopted.  Still, it doesn't mean they can't still screw it up.   The 121GW for example has the basic parts but the simple grill starter damaged the production meter with ease, just like so many UNI-T products.   Designers have to to their job.     
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 07, 2023, 05:46:01 pm
The worst part is that many people will never see past the fuse.

They'll see that fuse and think "It has the same protection as a Fluke!" even though the fuse only protects the 10A range and all the other ranges aren't any better than an Aneng.
Title: Re: Handheld meter robustness testing
Post by: floobydust on July 07, 2023, 06:44:01 pm
Once again, single PTC with nothing else to limit the current.  With what they are starting cost now, I'm surprised they aren't using proven designs.   They look to be about the same package as the parts that came in the 61E+.
Well, in all fairness it seems they might be learning a thing or two from your previous failure analysis. If my eyes are not failing me, the HV path seems to have a pair of PTCs, two pairs of clamping transistors and a larger resistor R57 they think might hold back a serious surge.

However, it is a hefty price for a somewhat basic Uni-T.

Assume R67.  I would need to trace it out.    Normally you would basically have two MOVs in series (shared on the return leg).   Ignore the second leg for now, you end up with one PTC in series with a MOV.  Say the MOV is 1kV.   If I apply 2kV, thats 1kV across the PTC.  Maybe it can handle it.  Those stupid piss ant 5mm parts they use in the cheap meters come apart and arc over.  Then there is nothing to limit the current.  In this case, let's say we have that SMT resistor in series with the clamp.  The clamp is basically a 0V and the 1kV is now across that resistor.  Maybe it survives.   Does it at 6kV?   :-DD    I like the tried and proven methods some of these companies have adopted.  Still, it doesn't mean they can't still screw it up.   The 121GW for example has the basic parts but the simple grill starter damaged the production meter with ease, just like so many UNI-T products.   Designers have to to their job.   

I see a (2512?) SMT 1.5k surge resistor R67, three dinky MOV's and two dinky PTC's. UniT claims it has 61010 certificates but you have to wonder given their fraudulant track record and the quite small parts. They charge way too much for basic protection as a "feature" given the $2 max. in extra parts.
The PTC's there is only one in china used in all their multimeters at 1,000V rated and as you say, it just blows up.

ACA, DCA it only displays to 0.1A resolution. ICK. I want my 60,000 counts back.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 07, 2023, 07:07:37 pm
As I said, I it would need to be traced out.  Normally we would expect the to MOVs for the two legs to share a common node that would tie back to that third MOV.  I am not sure if this is what they have done or not.   The surge rated resistors are then in series with the two PTCs.  Same old same old.  If R67 is rated for surge, odd they place it after the MOV where it only acts to limit the current to the low voltage clamp.   With it all routing to the switch, hard to say.    The 121GW for example will flash over the switch in my normal testing.  The just didn't consider it.   

I doubt this particular UNI-T would withstand the transients that I consider to make a meter robust but you never know.   I've looked at more of their products than any other and I've yet to see them get it right.   I doubt very much they all of a sudden have their shit together.   Now with the high costs, why would you ever do this route.  At least with the 61E, you could say, it's only $50 but it sorta gives you some higher resolution and a PC interface.  Sure, you may look at it funny and it dies but it's $50.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 07, 2023, 08:01:54 pm
So we're back to the big question: Does the meter have to survive the transient to get a safety certificate or does it only have to protect the user?

I'd say that a big bang in your hand isn't "protecting the user" - even if the blast is contained they might step back from fright, put their foot in a bucket and fall off the scaffolding.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 07, 2023, 09:13:43 pm
So we're back to the big question: Does the meter have to survive the transient to get a safety certificate or does it only have to protect the user?

I'd say that a big bang in your hand isn't "protecting the user" - even if the blast is contained they might step back from fright, put their foot in a bucket and fall off the scaffolding.

I would say YOU are back to ...  Don't wrap every one else into your safety chatter.   

I was mucking around a few weeks ago with some quartz crystals and was curious if I could tune their resonance frequency by adding a DC bias voltage across them.    I was using a meter to make these measurements and was commenting how this is a typical case where I would be concerned about using a crap meter.    Almost lost a cheap VNA that day.   Like cheap meters, they are somewhat disposable.   

I could care less about safety but I sure do care about a meters ability to survive some basic transients. 
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 07, 2023, 09:16:05 pm
I was hoping Joe, Dave, Kerry Wong, or another of my favorite YT'ers would look at this meter soon. I've been seeing it go for around $85 alone or $100 with the kit (clamp leads and magnetic hanger) for a 60K count meter and thought it looked like it had interesting features for the money. Sure, Dave's BM786 is a far better 60K count meter I'm sure (I do love mine), but the cost is twice as much. Not sure I've seen another 60K meter in this price range, at least from a brand you've actually heard of.

Note: I have an unashamed addiction to buying and collecting handheld multimeters of all stripes. I have some of everything, and multiples of several, including Fluke, Hioki, Brymen, Aneng/Zoyi/Zotec, Greenlee, Voltcraft, Craftsman, Uni-T, Owon, Hantek... you name it and I probably have at least one. I definitely don't need another meter. Just curious as to whether this one might scratch the itch to add to the collection, lol.
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on July 07, 2023, 09:32:05 pm
I was hoping Joe, Dave, Kerry Wong, or another of my favorite YT'ers would look at this meter soon. I've been seeing it go for around $85 alone or $100 with the kit (clamp leads and magnetic hanger) for a 60K count meter and thought it looked like it had interesting features for the money. Sure, Dave's BM786 is a far better 60K count meter I'm sure (I do love mine), but the cost is twice as much. Not sure I've seen another 60K meter in this price range, at least from a brand you've actually heard of.

Note: I have an unashamed addiction to buying and collecting handheld multimeters of all stripes. I have some of everything, and multiples of several, including Fluke, Hioki, Brymen, Aneng/Zoyi/Zotec, Greenlee, Voltcraft, Craftsman, Uni-T, Owon, Hantek... you name it and I probably have at least one. I definitely don't need another meter. Just curious as to whether this one might scratch the itch to add to the collection, lol.

Take a look at the specs though. This meter is literally an order of magnitude less accurate than any other 60k count meters. What good does that extra digit do if it's not accurate??? To me, it's close enough in price to the BM786 or 789 that if I want a 60k meter I would still prefer one of them. If I wanted cheap I would get the 61E which has better accuracy than this meter.

I am VERY confused by that teardown pic and the specs. That looks like a HY3131 chip, which is definitely capable (with the correct other hardware of course) of much better accuracy than this meter.
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 07, 2023, 09:38:11 pm
Take a look at the specs though. This meter is literally an order of magnitude less accurate than any other 60k count meters. What good does that extra digit do if it's not accurate??? To me, it's close enough in price to the BM786 or 789 that if I want a 60k meter I would still prefer one of them. If I wanted cheap I would get the 61E which has better accuracy than this meter.

I am VERY confused by that teardown pic and the specs. That looks like a HY3131 chip, which is definitely capable (with the correct other hardware of course) of much better accuracy than this meter.

Interesting. I didn't really look into the specs, I just saw a new 60K meter from Uni-T at an attractive price point. I just assumed it would be at least as accurate as a 61E+ (which I also happen to have). I don't understand why they wouldn't take a fairly proven (if not perfect) design like the 61E+ and add the precision to it for $25 more.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 12:22:52 am
I would say YOU are back to ...  Don't wrap every one else into your safety chatter.   

Huh? Somebody else mentioned "61010" a couple of posts up.

I believe you have access to a copy so maybe you could make a definitive statement on the matter. End speculation.
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on July 08, 2023, 01:23:16 am
Take a look at the specs though. This meter is literally an order of magnitude less accurate than any other 60k count meters. What good does that extra digit do if it's not accurate??? To me, it's close enough in price to the BM786 or 789 that if I want a 60k meter I would still prefer one of them. If I wanted cheap I would get the 61E which has better accuracy than this meter.

I am VERY confused by that teardown pic and the specs. That looks like a HY3131 chip, which is definitely capable (with the correct other hardware of course) of much better accuracy than this meter.

Interesting. I didn't really look into the specs, I just saw a new 60K meter from Uni-T at an attractive price point. I just assumed it would be at least as accurate as a 61E+ (which I also happen to have). I don't understand why they wouldn't take a fairly proven (if not perfect) design like the 61E+ and add the precision to it for $25 more.

That's what I don't understand either. This meter is using similar hardware as the BM786 so should be possible to have similar specs, but somehow has worse specs than their cheaper 61E+. What did they do so wrong??? Or did someone mess up the data sheets and manuals???
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 02:18:07 am
Interesting. I didn't really look into the specs, I just saw a new 60K meter from Uni-T at an attractive price point. I just assumed it would be at least as accurate as a 61E+ (which I also happen to have). I don't understand why they wouldn't take a fairly proven (if not perfect) design like the 61E+ and add the precision to it for $25 more.

Their web page claims "high precision", not high accuracy.

https://meters.uni-trend.com/product/ut117c/

Title: Re: Handheld meter robustness testing
Post by: floobydust on July 08, 2023, 02:36:05 am
It's got "electrician" features like the clamp on current probe with crappy 0.1A resolution and only the one big current shunt as well.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 03:28:56 am
It's got "electrician" features

Yep. No mA range.

TLDR; Another confusing meter from Uni-T.
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 08, 2023, 03:53:30 am
Interesting. I didn't really look into the specs, I just saw a new 60K meter from Uni-T at an attractive price point. I just assumed it would be at least as accurate as a 61E+ (which I also happen to have). I don't understand why they wouldn't take a fairly proven (if not perfect) design like the 61E+ and add the precision to it for $25 more.

Their web page claims "high precision", not high accuracy.

https://meters.uni-trend.com/product/ut117c/

Right. My point was the cheaper 61E+ has ±(0.05%+5) accuracy at 22K counts, so for ~$25 more in selling price couldn't they take the same accuracy and just add the additional precision? That was my assumption when I first saw the meter the other day, but didn't delve into the specs. The fact they're falling back to ±(0.3%+10) seems a bit absurd. I'd rather have 22K counts at the much higher accuracy.

EDIT: Actually the 61E+ is now selling for $82 on AliExpress, virtually same as this meter. I was thinking the 61E+ was quite a bit cheaper. So I guess the upshot between these meters is you can have precision or accuracy for the same price, just not both.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 05:22:28 am
EDIT: Actually the 61E+ is now selling for $82 on AliExpress, virtually same as this meter. I was thinking the 61E+ was quite a bit cheaper. So I guess the upshot between these meters is you can have precision or accuracy for the same price, just not both.

My question is why would you ever buy a Uni-T? You can get the 61E's accuracy in a Zoyi for much less money (the ZT-219/Aneng 870) and you can get a genuine CAT III meter from Brymen with input jack alert, etc., for the price of this meter.

The only interesting thing I see in the Uni-T lineup is a data logging meter for about $80 (the 61E). I don't think any other brand can match that.

(nb. Zoyi have some Bluetooth meters but I don't know if the protocol is known/hacked)

I know the UT61E has an army of fans though so that's just me.
Title: Re: Handheld meter robustness testing
Post by: floobydust on July 08, 2023, 05:28:01 am
Any multimeter that gets killed by a BBQ lighter, such a waste. ESD hits are not that different.

The UT117C has Bluetooth. No idea what UNI-T Smart Measure app is like or what it can do. I'm not holding my breath.

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 08, 2023, 07:05:51 am
I would say YOU are back to ...  Don't wrap every one else into your safety chatter.   

Huh? Somebody else mentioned "61010" a couple of posts up.

I believe you have access to a copy so maybe you could make a definitive statement on the matter. End speculation.
Like, I don't care about safety an my testing has nothing to do with it.  I've made that statement many times over the years.  Never sinks in with certain people. 
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 08, 2023, 07:08:18 am
I don't understand why they wouldn't take a fairly proven (if not perfect) design like the 61E+ and add the precision to it for $25 more.
Your idea of a proven and perfect design certainly differs from my own.   I like that 200MHz frequency counter function it has.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 08:54:31 am
Huh? Somebody else mentioned "61010" a couple of posts up.

I believe you have access to a copy so maybe you could make a definitive statement on the matter. End speculation.
Like, I don't care about safety an my testing has nothing to do with it.  I've made that statement many times over the years.  Never sinks in with certain people.

I never said you did.

The standard is written around "safety" so that's the word I'm forced to use. Please stop trying to be obtuse.

Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 08, 2023, 03:45:05 pm
EDIT: Actually the 61E+ is now selling for $82 on AliExpress, virtually same as this meter. I was thinking the 61E+ was quite a bit cheaper. So I guess the upshot between these meters is you can have precision or accuracy for the same price, just not both.

My question is why would you ever buy a Uni-T? You can get the 61E's accuracy in a Zoyi for much less money (the ZT-219/Aneng 870) and you can get a genuine CAT III meter from Brymen with input jack alert, etc., for the price of this meter.

The only interesting thing I see in the Uni-T lineup is a data logging meter for about $80 (the 61E). I don't think any other brand can match that.

(nb. Zoyi have some Bluetooth meters but I don't know if the protocol is known/hacked)

I know the UT61E has an army of fans though so that's just me.

I'm not a Uni-T fan by any means, but I have a thing for buying meters that interest me. Call it a compulsion, an addiction, whatever, but I've been accumulating handheld DMMs for 40 years. I hadn't counted recently but just did a quick inventory of those at hand, and I stopped counting at 22.

I have a few different Uni-T products (AWG, thermal camera), but the only Uni-T DMM I own is a 61E+, and really the only reason I bought it was its popularity, not its specs (although it certainly isn't bad for bench use). I know "serious" electronics folks can be a bit snobbish about our equipment, but you can't deny Uni-T's popularity and market share among hobbyists -- particularly the 61 series. Sure, I have several much better meters, but that's irrelevant to its suitability and value for a hobbyist's bench.

Kerry Wong posted this video:

https://www.youtube.com/watch?v=zIFYZ5AwDUI (https://www.youtube.com/watch?v=zIFYZ5AwDUI)

about his experience using the 61E+ as his primary meter for one year, saying at 0:36 (and I quote) "I really like this meter, and it's definitely a meter I will use on a daily basis." He also did this video:

https://www.youtube.com/watch?v=z4KClzousA8 (https://www.youtube.com/watch?v=z4KClzousA8)

comparing the AN870 and the 61E+, and it was really no comparison. He concluded with "Personally, I'd pay the premium for the more expensive Uni-T UT61E+ if I had to choose one or the other." Yes, the AN870 has temperature and a lower price, so of those are driving a buyer's motivations, then it's a no-brainer at ~$30. But the 61E+ beats it in virtually every other category.

BTW I also have an AN870, which is certainly a decent meter for the money, but as soon as you handle it you recognize it's very cheaply made. The 61E+ has a much higher fit & finish. In fact I have several Anengs and Zoyi/Zotecs, again for the price they're interesting and useful budget meters. I also have Flukes and Brymens, the latter being my favorite brand of handhelds (in fact just ordered a BM869s this week). But I'm interested in meters that interest me, regardless of price point. If this new 117C actually had 61E+ accuracy but with 60K counts for essentially the same price, I'd probably feel compelled to get one. Now I that I realize it really took a step backward on specs compared to the 61E+, especially now that the 61E+ is essentially the same price, it's less interesting and I doubt I'll pick one up. But you never know, I do have this DMM monkey on my back, after all. :)

I don't understand why they wouldn't take a fairly proven (if not perfect) design like the 61E+ and add the precision to it for $25 more.
Your idea of a proven and perfect design certainly differs from my own.   I like that 200MHz frequency counter function it has.   

Oh let me be clear: I do NOT think it's perfect, far from it. Hence my saying "if not perfect." And by "fairly proven" I refer simply to it's aforementioned popularity among hobbyists -- it has definitely proven itself a popular and capable meter for it's price point with that demographic. I wasn't implying that it's robustness (to use your favorite term) or suitability for professional electrician use is proven at all. Again, far from it.

EDIT: reformatted since the inline YT links expanded into previews that screwed up the formatting...
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 08, 2023, 04:07:48 pm
Huh? Somebody else mentioned "61010" a couple of posts up.

I believe you have access to a copy so maybe you could make a definitive statement on the matter. End speculation.
Like, I don't care about safety an my testing has nothing to do with it.  I've made that statement many times over the years.  Never sinks in with certain people.

I never said you did.

The standard is written around "safety" so that's the word I'm forced to use. Please stop trying to be obtuse.

As I have stated many times, that standard has nothing to do with my testing outside of that I based my transient on their open circuit voltage waveform.  Talking about safety from the context of this thread shows a lack of understanding.

That said, I had some RC person write me once how I was saving lives with all this testing.  I can imagine that electrical safety is on the minds of all the people playing with their RC toys.   Takes all kinds.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 08, 2023, 04:11:34 pm
And by "fairly proven" I refer simply to it's aforementioned popularity among hobbyists -- it has definitely proven itself a popular and capable meter for it's price point with that demographic.

Right, like the free Harbor Freight meters.  May be the most popular meter out there and tough to beat that price point. 
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 08, 2023, 04:41:33 pm
And by "fairly proven" I refer simply to it's aforementioned popularity among hobbyists -- it has definitely proven itself a popular and capable meter for it's price point with that demographic.

Right, like the free Harbor Freight meters.  May be the most popular meter out there and tough to beat that price point.

Touche, but I pointed out a specific demographic that I'm pretty sure are not seeking out free HF DT830 meters for use in their hobby. I would venture to speculate that the vast majority of HF meters (or any similar generic DT830 meter) are not popular with many electronics hobbyists. More likely just general home DIYers that picked one up because it was free and it works for them (maybe) to test a battery or an outlet or a light bulb socket once or twice a year. I seriously doubt you'd find many on an electronics bench like you would find the 61E+ and its ilk that cost at least an order of magnitude more than the $6 price of the HF meter (they don't give them away any more).

I had a few of those as well, back when they were still giving them away. Not because I liked them, but even they had a purpose. I had one in my truck console for years, probably still there. Don't know where the rest of them went, I think I gave some away.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 05:06:12 pm
He also did this video:

https://www.youtube.com/watch?v=z4KClzousA8 (https://www.youtube.com/watch?v=z4KClzousA8)

comparing the AN870 and the 61E+, and it was really no comparison.

Amazing how two people can watch the same video and see something completely different. If you look at the numbers on screen instead of listening to what he says it just doesn't match up. The only thing the Uni-T really won on was autorange speed (for resistance - screen updates were generally faster) and better leads.

"Better leads" are cheap, Aneng sells silicone/gold leads for a few bucks (https://www.aliexpress.com/item/4000810168665.html).

The "microvolt" test was really funny. He pointed out that the The Uni-T was flickering between 0 and 10 uV "when the input reached 5uV" but it was actually doing that the entire time, even with 0uV input.

When he got to 10uV it started flickering between 0uV and 20uV while he tells us it's "clearly more accurate" than the Aneng, which wasn't doing that.  :-//

The Aneng was clearly better at TRMS measurement and has better specs in general.

He concluded with "Personally, I'd pay the premium for the more expensive Uni-T UT61E+ if I had to choose one or the other."

His main reasoning was "because Uni-T is a well known brand in making quality test equipment, so I trust the specifications...", dispite having just demonstrated that the Aneng was well in spec.

PS: The Uni-T does have a bar graph, I'll give it that. I can't forgive it for wasting an entire selector position on "hFE" though.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 05:11:14 pm
BTW I also have an AN870, which is certainly a decent meter for the money, but as soon as you handle it you recognize it's very cheaply made.

I'm more of a fan of the AN860B+. It certainly feels more solid than the AN870 and the extra counts/accuracy of the AN870 doesn't really make much difference for hobby use..

The AN860B+ is disappearing from stores, being replaced by the AN870 so I bought a second one a few months ago before there's none left. I have to say it doesn't feel quite as solid as my old AN860B+. It's just a bit lighter in the hand somehow. Maybe I should weigh them both.
Title: Re: Handheld meter robustness testing
Post by: tomud on July 08, 2023, 05:29:11 pm
BTW I also have an AN870, which is certainly a decent meter for the money, but as soon as you handle it you recognize it's very cheaply made.

I'm more of a fan of the AN860B+.

I have better gear :) It's called Lavo 21  :-DMM

With a simple probe, it measures RF beautifully, not some slow digital bargraph  :bullshit: And it's pretty accurate for its age (1979 r)  :-DD

Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 05:29:53 pm
As I have stated many times, that standard has nothing to do with my testing

Yes, we've heard you.

Talking about safety from the context of this thread shows a lack of understanding.

The question isn't about safety. The question is whether or not the meter is supposed to survive it's rated transient without damage.

My belief is that the standard is ambiguous on this point but I don't have a copy the standard because it's expensive and not much use to me.

It seems logical to ask somebody who does have access to the standard if they could clarify things (or simply confirm that yes, it's ambiguous).  :-//

The only reason I used the word "safety" in your robustness thread is that because in my opinion a meter with exploding PTCs isn't a safe meter. You can still be injured even if no shrapnel or sparks make it out of the case.

If the standard allows exploding PTCs then I don't agree with the standard.

FWIW I asked the AI and got this answer:

(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1822672;image)
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on July 08, 2023, 05:46:21 pm
FWIW I asked the AI and got this answer:

Well that should settle it then!

Standards may have been rewritten or be different in certain regions (apparently CAT I is no longer a thing, at least in the EU) so I have no idea what the current answer might be.  However, I do remember a statement about it that I think either came from Fluke or was quoted by them that pretty clearly outlined that the meter needed to be able to at least indicate the presence of hazardous voltage at the conclusion of the test.  That doesn't imply no damage whatsoever, and there was some further discussion about how much error would be acceptable in such a reading.  If IIRC (which is a big if) I think their conclusion was that a 10% error was acceptable.  This was a fairly technical discussion, not an advertisement.

It's pretty hard to design something to take a big hit with that precise of a failure, so I'd presume (while admittedly not actually knowing) that the resulting design goal would typically be to get through the test with no damage at all.  Now if you have two different devices, one with a CAT III/1000V - CAT IV/600V rating designed to pass those tests without any damage and another with a CAT IV/1000V rating but only designed to pass that test without anything exploding through the case, it isn't easy to compare them directly.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on July 08, 2023, 08:35:21 pm
Talking about safety from the context of this thread shows a lack of understanding.

The question isn't about safety. The question is whether or not the meter is supposed to survive it's rated transient without damage.

My belief is that the standard is ambiguous on this point but I don't have a copy the standard because it's expensive and not much use to me.

It seems logical to ask somebody who does have access to the standard if they could clarify things (or simply confirm that yes, it's ambiguous).  :-//
I had momentary access to a few versions of the 61010 and it is quite ambiguous - I recall Joe had the same impression. I had commented before in this thread that IME such standards are subject to pressure from various players in the industry and such specific point might have well been kept somewhat ambiguous on purpose, clearing out the market for varying degrees of performance under transients.

One of the reasons that IMO is a strong indicator of the 61010 ambiguity is the line of Hypertough meters sold at the large Walmart stores in the US. Their M830B clone (manufactured by All-Sun) is way better than the average crap meters but I don't think it would qualify. However, Intertek mark is stamped left and right across its packaging and enclosure - no way Walmart would open themselves to a class action suit in case people started being electrocuted by one of their products.

https://www.walmart.com/ip/Hyper-Tough-Digital-Multimeter-TD35235J-New-4-25-in-Assembled-Product-Width/815000129?athbdg=L1600&from=/search (https://www.walmart.com/ip/Hyper-Tough-Digital-Multimeter-TD35235J-New-4-25-in-Assembled-Product-Width/815000129?athbdg=L1600&from=/search)

As usual, I did a review (https://youtu.be/SskaKJfSyXM) for my channel. My feelings are mixed - despite it is of a lesser quality than the A/B brand meters, it is built to a much higher quality than the M830B clones, which a great deal of people that can understand Portuguese uses them in extremely dangerous scenarios. Disclaimers galore but I would be happy if people used this particular one instead of the über crap stuff you find in Brasil. Hey, it withstood 280VAC applied to all its ranges - except battery tester, hfe and A/mA.
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 08, 2023, 11:12:20 pm
One of the reasons that IMO is a strong indicator of the 61010 ambiguity is the line of Hypertough meters sold at the large Walmart stores in the US. Their M830B clone (manufactured by All-Sun) is way better than the average crap meters but I don't think it would qualify.

 :) That meter reminds me of my "Big Clive" meter, which I enjoy using - it's simple, it takes up almost no space, and it stays on all day long without complaint.

The case is really boring though. You'd think they'd make it stand out from the crappy DT830a so you can easily tell them apart. eg. The Big Clive has a Fluke-like rubber boot.

it withstood 280VAC applied to all its ranges - except battery tester, hfe and A/mA.

The Big Clive claims 500V on most ranges in the manual but I haven't tested it.

(I don't see hFE on yours in your video...)

As usual, I did a review (https://youtu.be/SskaKJfSyXM) for my channel. My feelings are mixed - despite it is of a lesser quality than the A/B brand meters, it is built to a much higher quality than the M830B clones, which a great deal of people that can understand Portuguese uses them in extremely dangerous scenarios. Disclaimers galore but I would be happy if people used this particular one instead of the über crap stuff you find in Brasil.

Well... Brasil is a country full of suicide showers. People have a higher immunity to electricity there.  :)

FWIW I feel the same: If people are going to use a $4 meter to measure mains then a Big Clive or Hypertough is far superior to a Chinese race-to-the-bottom DT830.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on July 09, 2023, 03:22:19 pm
Talking about safety from the context of this thread shows a lack of understanding.

The question isn't about safety. The question is whether or not the meter is supposed to survive it's rated transient without damage.

My belief is that the standard is ambiguous on this point but I don't have a copy the standard because it's expensive and not much use to me.

It seems logical to ask somebody who does have access to the standard if they could clarify things (or simply confirm that yes, it's ambiguous).  :-//
I had momentary access to a few versions of the 61010 and it is quite ambiguous - I recall Joe had the same impression. I had commented before in this thread that IME such standards are subject to pressure from various players in the industry and such specific point might have well been kept somewhat ambiguous on purpose, clearing out the market for varying degrees of performance under transients.

One of the reasons that IMO is a strong indicator of the 61010 ambiguity is the line of Hypertough meters sold at the large Walmart stores in the US. Their M830B clone (manufactured by All-Sun) is way better than the average crap meters but I don't think it would qualify. However, Intertek mark is stamped left and right across its packaging and enclosure - no way Walmart would open themselves to a class action suit in case people started being electrocuted by one of their products.

I've posted sections of the standards and have written how I have contacted some of the big companies to get their take.   Nothing there has changed.  From the posts, it doesn't seem anyone else has done any further research on it.     

I've mentioned before that I think Intertek has become a bloated, ineffective monopoly.   Worse, it seems much of the cert is now rubber stamping for a price.  I think it's more about trying to control trade than safety.   My thoughts on that have not changed and this extends far beyond handheld multimeters. 
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on July 10, 2023, 02:54:27 am
One of the reasons that IMO is a strong indicator of the 61010 ambiguity is the line of Hypertough meters sold at the large Walmart stores in the US. Their M830B clone (manufactured by All-Sun) is way better than the average crap meters but I don't think it would qualify.

 :) That meter reminds me of my "Big Clive" meter, which I enjoy using - it's simple, it takes up almost no space, and it stays on all day long without complaint.

The case is really boring though. You'd think they'd make it stand out from the crappy DT830a so you can easily tell them apart. eg. The Big Clive has a Fluke-like rubber boot.
I wasn't sure what you meant by this meter but I found your other thread.
https://www.eevblog.com/forum/testgear/trashy-meters-redux/ (https://www.eevblog.com/forum/testgear/trashy-meters-redux/)

Quite interesting indeed, which Clive's meter says CAT I and I think it is more adequate to its physical abilities. The All-Sun says CAT III 300V, which it claims but I am very suspicious, having the GS mark or not.


it withstood 280VAC applied to all its ranges - except battery tester, hfe and A/mA.

The Big Clive claims 500V on most ranges in the manual but I haven't tested it.

(I don't see hFE on yours in your video...)
My measurement was quite close to the meter's maximum claim of 300V, but I should pull my HiPot tester and see if I can get it to display more (up to 2kV?).

Well... Brasil is a country full of suicide showers. People have a higher immunity to electricity there.  :)
Our ability to withstand 220V across our body is legendary. :-DD
(i did this for 23 years daily, then I moved to a city of just 127V - amateurs!)
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on July 10, 2023, 03:01:00 am
I've mentioned before that I think Intertek has become a bloated, ineffective monopoly.   Worse, it seems much of the cert is now rubber stamping for a price.  I think it's more about trying to control trade than safety.   My thoughts on that have not changed and this extends far beyond handheld multimeters.
If you think Intertek is like that, there is a chance UL follows suit. I worked with them and, despite they were very professional and completed the work to its extent, there was a perceptible "checkbox-like" attitude.

In other words, it smelled like a CYA operstion more than a work with pride in its technical merits. Oh well...
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 10, 2023, 05:34:29 am
:) That meter reminds me of my "Big Clive" meter, which I enjoy using - it's simple, it takes up almost no space, and it stays on all day long without complaint.

The case is really boring though. You'd think they'd make it stand out from the crappy DT830a so you can easily tell them apart. eg. The Big Clive has a Fluke-like rubber boot.
I wasn't sure what you meant by this meter but I found your other thread.
https://www.eevblog.com/forum/testgear/trashy-meters-redux/ (https://www.eevblog.com/forum/testgear/trashy-meters-redux/)

Quite interesting indeed

https://www.newark.com/pt-BR/duratool/d03047/digital-multimeter-manual-2mohm/dp/78AH1731 (https://www.newark.com/pt-BR/duratool/d03047/digital-multimeter-manual-2mohm/dp/78AH1731)

Ref:

https://www.youtube.com/watch?v=-QDW0LRQVrY (https://www.youtube.com/watch?v=-QDW0LRQVrY)
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 10, 2023, 01:01:19 pm
:) That meter reminds me of my "Big Clive" meter, which I enjoy using - it's simple, it takes up almost no space, and it stays on all day long without complaint.

The case is really boring though. You'd think they'd make it stand out from the crappy DT830a so you can easily tell them apart. eg. The Big Clive has a Fluke-like rubber boot.
I wasn't sure what you meant by this meter but I found your other thread.
https://www.eevblog.com/forum/testgear/trashy-meters-redux/ (https://www.eevblog.com/forum/testgear/trashy-meters-redux/)

Quite interesting indeed

https://www.newark.com/pt-BR/duratool/d03047/digital-multimeter-manual-2mohm/dp/78AH1731 (https://www.newark.com/pt-BR/duratool/d03047/digital-multimeter-manual-2mohm/dp/78AH1731)

Ref:

https://www.youtube.com/watch?v=-QDW0LRQVrY (https://www.youtube.com/watch?v=-QDW0LRQVrY)


Damn you, Fungus. Now I'm in for three of Clive's meters (need to feed this meter monkey on my back).

I like having "disposable" meters located in convenient places and I think I'm down to my last HF freebie. Plus this one is built way better, so may not be as disposable. Can't beat 7 bucks a pop, especially with the HF's going for $6 now. Like you I decided to get three to have spares and make better use of the flat shipping rate.
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 12, 2023, 12:29:00 am
Damn you, Fungus. Now I'm in for three of Clive's meters (need to feed this meter monkey on my back).

I like having "disposable" meters located in convenient places and I think I'm down to my last HF freebie. Plus this one is built way better, so may not be as disposable. Can't beat 7 bucks a pop, especially with the HF's going for $6 now. Like you I decided to get three to have spares and make better use of the flat shipping rate.

And they're here. Next day shipping for $9.99? Nice!

While the test leads are shrouded and appear at a glance to be better quality than the typical $5 meter's probes, as I was wiping the tips on the first meter with an IPA pad to see if it improved tip resistance, the entire tip insert pulled out of the probe. LOL. I'll still stash these around the shop, garage, cars, etc. They'll serve their intended purpose just fine, I'm sure.

One unit sported an updated box showing the meter with the black case, while the other two boxes showed yellow. All three meters are all black though. The rubber holster looks more orange than yellow. Wouldn't want anyone mistaking these for Flukes I guess.

EDIT: Ha, also just noted these are from the same "batch" 2106 as your meters. Fake batch numbers anyone? Really big batches? Really slow sales?

(http://i.imgur.com/PTfPbPnl.jpg) (https://imgur.com/PTfPbPn.jpg)
Title: Re: Handheld meter robustness testing
Post by: Fungus on July 12, 2023, 03:53:08 am
EDIT: Ha, also just noted these are from the same "batch" 2106 as your meters. Fake batch numbers anyone? Really big batches? Really slow sales?

Could be a big batch.  :) Weird that you'd have two different box colors in the same batch though.  :-\

It could also be a date code: 2106 = week 6 of 2021.

I just looked and Big Clive's has a sticker on it:
(https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/?action=dlattach;attach=1825624;image)
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on July 12, 2023, 03:57:14 am
Ignore my box comment. I noticed later that every box has black on one side and yellow on the other side.  :palm:
Title: Re: Handheld meter robustness testing
Post by: floobydust on July 12, 2023, 04:02:26 am
Even within the model number, there are widely varying builds and quality. The cheapest 830 family are COB with missing protection diodes on the boards. Some seem to be assembled by slave labour or children.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on September 24, 2023, 01:42:05 am
Just a link of some discussion about this thread and my testing.   

https://www.eevblog.com/forum/beginners/why-do-hobbyists-purchase-the-most-expensive-handheld-dmms/ (https://www.eevblog.com/forum/beginners/why-do-hobbyists-purchase-the-most-expensive-handheld-dmms/)

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 09, 2023, 01:45:33 pm
Member Rsjsouza suggests meters have gone down hill (my words, not his).  It's been eight years since I ran that first batch of $50 meters.   Is there any interest in seeing a repeat?   

For a meter to qualify, it must meet  the following:

<$60 USD with shipping
Available on eBay or Amazon (They must be easily obtained in brand new form.  You should be able to buy one and repeat my tests.  No used meters.)
Auto range (manual range requires way too much time to test)
Must not be a previously tested model.  No repeats. 
>1999 count (I started looking at meters that I though may be useful for electronics which is why the failures went down and costs increased.  For low cost meters, anything goes.)

If you have a meter you would like to see tested, feel free to post the brand, model, supplier.   

Most likely, I will only transient test the meters, unless we actually find a gem in the mix.  I would most likely purchase another Amprobe AM510 to run with them (runner up).   Also would include the original Fluke 101 that dominated that test by a wide margin.  That meter was never damaged unlike the original AM510 that I had repaired. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on November 09, 2023, 03:11:25 pm
If you have a meter you would like to see tested, feel free to post the brand, model, supplier.   

You could expose Kaiweets for the rubbish that I presume it is.  The KM 401 is about $25 on Amazon and appears to imply that it is suitable for industrial use since it has NCV and phase sequence functions (although I'm mystified as to how it works without a third connection).  It has CAT III/1000V and CAT IV/600V ratings and a CE mark.  It even has a flashlight for when you are working on a 575V irrigation pump motor outside in the dark, trying to get it going before the approaching thunderstorm reaches you.  After, all, CAT IV/600 has you covered, right?

Yes, I know, your tests aren't about safety.  It will still be interesting to see how miserably these meters do in your tests.

https://www.amazon.com/KAIWEETS-Multimeter-Auto-Ranging-Capacitance-Temperature/dp/B0CCXRCHD3 (https://www.amazon.com/KAIWEETS-Multimeter-Auto-Ranging-Capacitance-Temperature/dp/B0CCXRCHD3)
Title: Re: Handheld meter robustness testing
Post by: Grandchuck on November 09, 2023, 03:41:13 pm
UNI-T 125C

https://www.amazon.com/UNI-T-Multimeter-Resistance-Capacitance-Continuity/dp/B08TT8H4GS/ref=sr_1_5?crid=1C7PNB7QZEIKG&keywords=UNI-T%2BUT125C%2BDigital%2BMultimeter&qid=1699544398&sprefix=uni-t%2But125c%2Bdigital%2Bmultimeter%2Caps%2C78&sr=8-5&th=1 (https://www.amazon.com/UNI-T-Multimeter-Resistance-Capacitance-Continuity/dp/B08TT8H4GS/ref=sr_1_5?crid=1C7PNB7QZEIKG&keywords=UNI-T%2BUT125C%2BDigital%2BMultimeter&qid=1699544398&sprefix=uni-t%2But125c%2Bdigital%2Bmultimeter%2Caps%2C78&sr=8-5&th=1)
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 09, 2023, 04:24:28 pm
I'd like to see one of those big chunky Aneng/Zotech meters, the ones that supposedly have a 61010 certificate.

eg. This one: https://zotektools.com/products/zoyiztm1/ (https://zotektools.com/products/zoyiztm1/)

The certificate is in the "Product certification" tab.

The Aneng versions are these:
https://www.aliexpress.com/item/33005381639.html (https://www.aliexpress.com/item/33005381639.html)
https://www.aliexpress.com/item/33009371206.html (https://www.aliexpress.com/item/33009371206.html)
Title: Re: Handheld meter robustness testing
Post by: multiJ on November 09, 2023, 05:01:34 pm
Uni-T
UT33A+ (or UT131A in Europe)
https://www.ebay.com/itm/295459864825 (https://www.ebay.com/itm/295459864825)
or UT123

Any Kaiweets -these seem to be advertised everywhere these days.
For example, HT118A
https://www.amazon.com/KAIWEETS-Multimeter-Resistance-Capacitance-Temperature/dp/B07SHLS639?th=1 (https://www.amazon.com/KAIWEETS-Multimeter-Resistance-Capacitance-Temperature/dp/B07SHLS639?th=1)

Klein Tools
If there is something at this price point in the US.

Amazon do not sell branded multimeters any more. Maybe something from CEM?

Etekcity
MSR-A2000
https://www.amazon.com/Etekcity-Multimeter-Capacitance-Temperature-MSR-A2000/dp/B09HP6M8CW/ref=sr_1_30?crid=3IBQTU73ATXDE&keywords=cem%2Bmultimeter&qid=1699548997&sprefix=cem%2Bmultimete%2Caps%2C203&sr=8-30&th=1 (https://www.amazon.com/Etekcity-Multimeter-Capacitance-Temperature-MSR-A2000/dp/B09HP6M8CW/ref=sr_1_30?crid=3IBQTU73ATXDE&keywords=cem%2Bmultimeter&qid=1699548997&sprefix=cem%2Bmultimete%2Caps%2C203&sr=8-30&th=1)

PeakTech
P3350
https://www.amazon.com/PeakTech-3350-Multimeter-Resistance-Capacitance/dp/B09N15W9GX/ref=sr_1_37?crid=21P4WU5WF2S5M&keywords=Digital+Multimeter&qid=1699549438&sprefix=digital+multimeter+%2Caps%2C203&sr=8-37 (https://www.amazon.com/PeakTech-3350-Multimeter-Resistance-Capacitance/dp/B09N15W9GX/ref=sr_1_37?crid=21P4WU5WF2S5M&keywords=Digital+Multimeter&qid=1699549438&sprefix=digital+multimeter+%2Caps%2C203&sr=8-37)

Title: Re: Handheld meter robustness testing
Post by: bdunham7 on November 09, 2023, 05:40:24 pm
Klein Tools
If there is something at this price point in the US.

The Klein MM400 is under $60.  From teardown videos it appears to have a single-PTC MOV-less design and a CAT III/600V rating, which seems suspect.  However, it also appears to have a more limited function set, so perhaps they are able to pull off a "withstand without clamping HV" design.  It does have a pretty decent looking set of input resistors, but not the single large ~1k surge resistor.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2023, 01:20:17 am
I'd like to see one of those big chunky Aneng/Zotech meters, the ones that supposedly have a 61010 certificate.

eg. This one: https://zotektools.com/products/zoyiztm1/ (https://zotektools.com/products/zoyiztm1/)

The certificate is in the "Product certification" tab.

The Aneng versions are these:
https://www.aliexpress.com/item/33005381639.html (https://www.aliexpress.com/item/33005381639.html)
https://www.aliexpress.com/item/33009371206.html (https://www.aliexpress.com/item/33009371206.html)

Read the selection criteria and pick a meter with autorange.  These manual range meters suck up too much time.   
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 10, 2023, 05:19:08 am
I'd like to see one of those big chunky Aneng/Zotech meters, the ones that supposedly have a 61010 certificate.
Read the selection criteria and pick a meter with autorange.  These manual range meters suck up too much time.   

Both those meters have auto ranges (the blue stops on the dials).

One even has "full auto" where you don't even have to select volts/ohms/etc.

But whatever... your rules.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on November 10, 2023, 11:28:17 am
Joe, I think one that has been making the rounds is the Kaiweets HT118A (https://www.amazon.com/KAIWEETS-Multimeter-Resistance-Capacitance-Temperature/dp/B07SHLS639/) and also sold cheaper as AstroAI M6KOR (https://www.amazon.com/AstroAI-Multimeter-Auto-Ranging-Capacitance-Temperature/dp/B08FDVQDM5/) - mind you, these are better built than the absolute bottom of the barrel I mentioned in the other thread.

The Aneng AN870/Richmeters RM219/Zoyi ZT219 are quite popular - can be had at Amazon (https://www.amazon.com/Voltage-Multimeter-True%E2%80%91RMS-Laboratory-Enthusiasts/dp/B08RS8P52Q) or cheaper at Aliexpress (https://www.aliexpress.us/item/3256805357901440.html). 

I personally find the Richmeters RM113D (https://www.aliexpress.us/item/3256801361427460.html) (also sold as NJTY T21D (https://www.aliexpress.us/item/3256801284697185.html)) appealing for its small size and ultra low cost. It has been mechanically and thermally abused by me in the past year or so and it has kept it together well, but I know it is a weak contender (electrically speaking). It can be had for lunch money.

Two that I know are the bottom of the barrel are the Aneng M118A (https://www.aliexpress.us/item/3256804915481454.html) (fully automatic) and the Richmeters RM102Pro (https://www.aliexpress.com/i/2255800056819348.html) (also known as Aneng AN113D (https://www.aliexpress.us/item/2255800220607404.html)).

If you are interested in looking at the fully automatic like the M118A, these cellphone-style case meters could be interesting. Both the Kaiweets KM601s (https://www.amazon.com/KAIWEETS-Multimeter-Rechargeable-Resistance-Capacitance/dp/B0C4TNJPQT/) or the AstroAI MUS10KRD (https://www.amazon.com/AstroAI-Multimeter-Auto-Ranging-Capacitance-Temperature/dp/B091FCWMP1/) are probably much better than the  Aneng.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2023, 12:53:42 pm
I will normally test these meters with the switch set to every setting, except for current.   Meters that share the V and I on one connector are typically not ran.  Problem being the fuse will blow.  Some place the fuse in-line with shared functions and then the meter is dead.   I've seen some that use a PTC rather than a fuse for the low current shared input.  These may be ok to run, if you knew this is how it was designed.  So no manual ranged meters and I shy away from meters without dedicated current connections.

Not sure on the full auto meters.  If they could be manually set to the various functions, they may be alright to test. 

Room for a few more.
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on November 10, 2023, 03:39:14 pm
Let me check the RM113D and the RM102Pro. IIRC they physically switch the fuse out when not in mA.
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 10, 2023, 05:14:20 pm
Room for a few more.

This one: https://www.aliexpress.com/item/33008555587.html (https://www.aliexpress.com/item/33008555587.html)

 :)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2023, 05:26:01 pm
Room for a few more.

This one: https://www.aliexpress.com/item/33008555587.html (https://www.aliexpress.com/item/33008555587.html)

 :)

I couldn't find it on Amazon or eBay.   If it is sold under a different brand/model, let me know.
Title: Re: Handheld meter robustness testing
Post by: Fungus on November 10, 2023, 05:35:31 pm
This one: https://www.aliexpress.com/item/33008555587.html (https://www.aliexpress.com/item/33008555587.html)

 :)

I couldn't find it on Amazon or eBay.   If it is sold under a different brand/model, let me know.
[/quote]

It's made by Zotech and has lots of brands. The S3 or S4 are the ones to get.

On ebay:
https://www.ebay.com/itm/385405636448 (https://www.ebay.com/itm/385405636448)
https://www.ebay.com/itm/353583550051 (https://www.ebay.com/itm/353583550051)
https://www.ebay.com/itm/384324938870 (https://www.ebay.com/itm/384324938870)

Amazon is the worlds worst place to buy multimeters
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on November 10, 2023, 05:57:59 pm
Joe, I think one that has been making the rounds is the Kaiweets HT118A (https://www.amazon.com/KAIWEETS-Multimeter-Resistance-Capacitance-Temperature/dp/B07SHLS639/) and also sold cheaper as AstroAI M6KOR (https://www.amazon.com/AstroAI-Multimeter-Auto-Ranging-Capacitance-Temperature/dp/B08FDVQDM5/) - mind you, these are better built than the absolute bottom of the barrel I mentioned in the other thread.

The Kaiweets HT118E is the upgraded version. 20K counts vs 6K. These are actually pretty good meters for the money with rave reviews all over (don't know about protection though)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 10, 2023, 07:19:49 pm
Joe, I think one that has been making the rounds is the Kaiweets HT118A (https://www.amazon.com/KAIWEETS-Multimeter-Resistance-Capacitance-Temperature/dp/B07SHLS639/) and also sold cheaper as AstroAI M6KOR (https://www.amazon.com/AstroAI-Multimeter-Auto-Ranging-Capacitance-Temperature/dp/B08FDVQDM5/) - mind you, these are better built than the absolute bottom of the barrel I mentioned in the other thread.

The Kaiweets HT118E is the upgraded version. 20K counts vs 6K. These are actually pretty good meters for the money with rave reviews all over (don't know about protection though)

I wouldn't be surprised if 90% of what I consider fodder doesn't have rave reviews.  All depends what your criteria is.  I want products that hold up.  Others want sexy colors...
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on November 10, 2023, 09:44:44 pm
This one: https://www.aliexpress.com/item/33008555587.html (https://www.aliexpress.com/item/33008555587.html)

 :)

I couldn't find it on Amazon or eBay.   If it is sold under a different brand/model, let me know.

It's made by Zotech and has lots of brands. The S3 or S4 are the ones to get.

On ebay:
https://www.ebay.com/itm/385405636448 (https://www.ebay.com/itm/385405636448)
https://www.ebay.com/itm/353583550051 (https://www.ebay.com/itm/353583550051)
https://www.ebay.com/itm/384324938870 (https://www.ebay.com/itm/384324938870)

Amazon is the worlds worst place to buy multimeters
These are the Aneng M118A I referenced in my post above. They should provide a nice pyro show.  ;D
Title: Re: Handheld meter robustness testing
Post by: armandine2 on November 10, 2023, 10:08:53 pm
I want products that hold up.  Others want sexy colors...

just watched the poor performing Vici VC99 video and wonder if the VC97A will do better?

It has anti high voltage  :palm:

Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 11, 2023, 12:58:52 am
It has anti high voltage  :palm:

 :-DD :-DD
Title: Re: Handheld meter robustness testing
Post by: mqsaharan on November 11, 2023, 03:56:22 am
Run UT60EU or UT60BT. It has a full set of basic functions. If it is robust enough, it could be a good choice for a beginner DMM.
https://www.amazon.com/UNI-T-Multimeter-Transmission-Capacitance-Temperature/dp/B0CDRX6DF3/ref=sr_1_1?crid=1MLCVCY69GQNX&keywords=ut60eu&qid=1699673515&sprefix=ut60eu%2Caps%2C461&sr=8-1&th=1 (https://www.amazon.com/UNI-T-Multimeter-Transmission-Capacitance-Temperature/dp/B0CDRX6DF3/ref=sr_1_1?crid=1MLCVCY69GQNX&keywords=ut60eu&qid=1699673515&sprefix=ut60eu%2Caps%2C461&sr=8-1&th=1)
Title: Re: Handheld meter robustness testing
Post by: NoMoreMagicSmoke on November 16, 2023, 01:29:48 am
I think a hardware store meter shootout would be interesting. Perhaps a Southwire, Ideal, Klein, etc. shootout. Maybe even throw in a higher end Harbor Freight meter as well. At the end of the day, are any of those meters even remotely decent or are they all the same quality as the AliExpress specials?
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 23, 2023, 07:40:06 pm
I ordered some of your suggested low cost meters.  I think we all know the grill starter will damage all the UNI-T products and I doubt any of us are expecting any of the others to survive the low voltage generator.   So, to mix things up a bit, I bought what I consider should make a decent meter for electronics work.   Will it replace my Brymen BM869s....  Stay tuned.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on November 27, 2023, 03:30:01 am
Klein Tools
If there is something at this price point in the US.

The Klein MM400 is under $60.  From teardown videos it appears to have a single-PTC MOV-less design and a CAT III/600V rating, which seems suspect.  However, it also appears to have a more limited function set, so perhaps they are able to pull off a "withstand without clamping HV" design.  It does have a pretty decent looking set of input resistors, but not the single large ~1k surge resistor.

The low cost meters have started to arrive.  Note how that Klein MM400 shares the current input.   :--   I give the big thumbs down and it's not even out of the wrapper.   If the fuse is in series with the shared functions, my plan is to pull it and replace it with a short.  I have no desire to replace a fuse after every transient.   

The others are fine so far.
Title: Re: Handheld meter robustness testing
Post by: GuidoK on December 19, 2023, 07:28:52 pm
So, to mix things up a bit, I bought what I consider should make a decent meter for electronics work.   Will it replace my Brymen BM869s....  Stay tuned.

I can't wait to see which one it is.

I'd be really curious to the Metrix MTX 3293B or it's Chauvin Arnoux equivalent, that sadly didn't make win the poll from the keysight a while back.

All the cheap kaiweets etc stuff.... I really don't care about that. I don't see any significant useful progression made in that segment.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 19, 2023, 07:31:47 pm
... I really don't care about that. ...

Others do. 
Title: Re: Handheld meter robustness testing
Post by: GuidoK on December 20, 2023, 02:36:11 am

Others do.

Yes I understand. But in the light of the robustness testing that you do, do you expect any surprises of the ~sub$50 kaiweets/zotek/aneng multimeters that flood the market and sponsored youtube channels in that regard?
That one of them stands out and has a robustly designed front end that will perform well in your test?
Obviously the only real way to find out is to test them, but my expectations are pretty low regarding that aspect.
The functional tests that you do with odd voltages (like detecting ac waveforms with a dc bias etc) might be the most interesting part for those cheap meters.

Some time ago I suggested the amazon commercial 90DM610 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg3130620/?topicseen#msg3130620) which was a rebranded Cem DT-9562 that at that time retailed at $49 on amazon that looks like it may have a pretty decent robust front end inside, but afaik that meter is not available anymore (certainly not at that price at least)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 20, 2023, 03:36:28 am

Others do.

Yes I understand. But in the light of the robustness testing that you do, do you expect any surprises of the ~sub$50 kaiweets/zotek/aneng multimeters that flood the market and sponsored youtube channels in that regard?
That one of them stands out and has a robustly designed front end that will perform well in your test?

I am not expecting any surprises.  Based on previous experience, they will all work out of the box measuring components from my component test box accurately.   UNI-T meters will be damaged from a low ESD event.  One may fail with the low voltage 60Hz.  The others will not survive the low voltage generator.  None will be repairable. 

A few viewers will complain how the tests are unrealistic.  How it says right on the meter 600V max.  How we can't draw any conclusions from a sample size of one.  How dare I take a perfectly good meter and damage it.  How I am biased.  How they had this meter for 20 years and it has never had any problems. 

Obviously the only real way to find out is to test them, but my expectations are pretty low regarding that aspect.

Agree, this is why we test them and I suspect most have very low expectations. 

The functional tests that you do with odd voltages (like detecting ac waveforms with a dc bias etc) might be the most interesting part for those cheap meters.
Some time ago I suggested the amazon commercial 90DM610 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg3130620/?topicseen#msg3130620) which was a rebranded Cem DT-9562 that at that time retailed at $49 on amazon that looks like it may have a pretty decent robust front end inside, but afaik that meter is not available anymore (certainly not at that price at least)

As far as testing, I have not yet decided what all I will do with them.   It may depend on the meter.   

I've looked at a few CEM products.  Anytime someone talks about what they "look like" inside, I am reminded of that UNI-T UT181A of that last Keysight U1282A.  Both very expensive.  Both damaged from next to nothing.  At least I could repair the UNI-T (very rare)  where the Keysight is worthless.   I did offer to buy the Keysight meter Dave used for his video for parts in hopes to revive it but wasn't able to strike a deal.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on December 20, 2023, 06:57:47 pm
A few viewers will complain how the tests are unrealistic.  How it says right on the meter 600V max.  How we can't draw any conclusions from a sample size of one.  How dare I take a perfectly good meter and damage it.  How I am biased.  How they had this meter for 20 years and it has never had any problems. 
There is another category: "I used this meter in my three phase distribution panel and not only it read 380V but I am still alive to tell the story".

The low key meters have their place and they will be stretched by their users far beyond any "safe" margin. Heck, even I did measurements with my dad's ICE 680R that would be considered child endangerment nowadays.

That doesn't detract in anyway the value of putting them to the paces. Besides, if they explode, people will tune in for the pyrotechnics. 😜
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 20, 2023, 09:01:50 pm
T
There is another category: "I used this meter in my three phase distribution panel and not only it read 380V but I am still alive to tell the story".

True.
****
The comments from hackaday when I first started running these tests is priceless.

https://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/
****

Well, I ran the first meter today and am going to have to eat my words.  Results were not at all what I was expecting.  There wasn't even a hint of drama.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 21, 2023, 03:00:33 am
Most electrically robust UNI-T product I have looked at to date, outside of the ones I modified... 

https://www.youtube.com/watch?v=eBbck0gHvRo (https://www.youtube.com/watch?v=eBbck0gHvRo) 
Title: Re: Handheld meter robustness testing
Post by: GuidoK on December 21, 2023, 09:21:01 pm
Nice video. That was indeed an unexpected outcome, since EN61326 wasn't mentioned in the manual.
Let's hope all future Uni-T's meters handle the grill starter with no problems.
And it shows that a reasonable robust meter doesn't have to be expensive, although this is of course a pretty simple and limited multimeter.
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 21, 2023, 10:09:52 pm
Nice video. That was indeed an unexpected outcome, since EN61326 wasn't mentioned in the manual.
Let's hope all future Uni-T's meters handle the grill starter with no problems.
And it shows that a reasonable robust meter doesn't have to be expensive, although this is of course a pretty simple and limited multimeter.

The Y1 transistors they selected are a bit more stout than what I normally see for a clamp and they took some abuse.  Had they used a second PTC, or better, just added the proven surge rated resistor, I am guessing the meter would have gone a lot further.   Then again, had the PTCs broke down the meter would have been in the recycle bin.  Good to see them using better parts even in such a cheap meter.    That shared current/fuse/spark gap IMO was a poor choice. 

Keep in mind when I first started to look at how robust these meters are, the meter that was the runner up survived 5kV.  It could also be repaired.  I tested it a second time on the new transient generator and it once again survived 5kV.   That meter was also under $50 and had a lot more features.   

https://www.aliexpress.com/i/3256803936810470.html?gatewayAdapt=4itemAdapt (https://www.aliexpress.com/i/3256803936810470.html?gatewayAdapt=4itemAdapt)
Title: Re: Handheld meter robustness testing
Post by: GuidoK on December 21, 2023, 11:10:51 pm

Keep in mind when I first started to look at how robust these meters are, the meter that was the runner up survived 5kV.  It could also be repaired.  I tested it a second time on the new transient generator and it once again survived 5kV.   That meter was also under $50 and had a lot more features.   


Do you mean the Amprobe AM-510?
Because that retails (here in europe at least) currently for almost €100, whereas that uni-T is roughly 5 times as cheap (€19).
(these prices are including ~21% VAT)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 22, 2023, 12:19:38 am
Yes.  It looks like Amprobe discontinued it.   
Title: Re: Handheld meter robustness testing
Post by: rsjsouza on December 22, 2023, 12:32:56 am
The Y1 transistors they selected are a bit more stout than what I normally see for a clamp and they took some abuse. 

(...)

https://www.aliexpress.com/i/3256803936810470.html?gatewayAdapt=4itemAdapt (https://www.aliexpress.com/i/3256803936810470.html?gatewayAdapt=4itemAdapt)
Thanks for sharing the link and P/N. I have some meters here that need their clamps changed and I keep forgetting to look at your older videos to get the P/N.

The SS8050 is also available at Mouser:
https://www.mouser.com/ProductDetail/Comchip-Technology/SS8050-HF?qs=T%252BzbugeAwjjubHjgf%252BCy6w%3D%3D (https://www.mouser.com/ProductDetail/Comchip-Technology/SS8050-HF?qs=T%252BzbugeAwjjubHjgf%252BCy6w%3D%3D)
Title: Re: Handheld meter robustness testing
Post by: GuidoK on December 30, 2023, 10:42:02 pm
Regarding the cheap multimeter robustness testing, this might be an interesting specimen.
Fnirsi DMT-99
https://www.aliexpress.com/item/1005006225669621.html (https://www.aliexpress.com/item/1005006225669621.html)

Not that I expect it to be very robust, being a cheap (chinese) meter, but it's not from a typical DMM manufacturer (so who knows....) and it has an interesting feature that it can do some graphical logging. (quite unique in this price range)

It's one of those automatic style meters though, so I expect it to be a nuisance to use  ::)
It's quite a new model, so there's not that much info on it out there (1 or 2 youtube reviews though).
But.... I haven't seen any CAT rating on the meter (in the youtube reviews) or in the manual, nor any compliance to an EN standard, so that might be interesting  ::)
I think that would make it illegal to sell here in the EU at least (I think compliance to EN61010 for devices that can be connected to mains, including multimeters, in the EU is mandatory)  :o

Best wishes for the New Year  :-+
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on December 31, 2023, 04:37:35 pm
After talking with Fluke early on, I had initially hoped that meters with a higher CAT rating would be more robust.  I suspect if every company took the same stance as to what constitutes a pass/failure, that would be true.  But, as we have seen in many instances this has not been the case.    The only correlation I seem to notice when comparing the IEC standards how robust the products are is if they pass the EMC standards.   
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 15, 2024, 08:06:48 pm
Transient Testing the UNI-T UT33A+ 2000 count DMM.

https://www.youtube.com/watch?v=Lb7rIwVbE70 (https://www.youtube.com/watch?v=Lb7rIwVbE70)
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 17, 2024, 07:51:12 pm
Transient Testing the KAIWEETS KM401 4000 count DMM

https://www.youtube.com/watch?v=tmB_xdUjQoc (https://www.youtube.com/watch?v=tmB_xdUjQoc)
Title: Re: Handheld meter robustness testing
Post by: Veteran68 on March 18, 2024, 02:46:34 am
Transient Testing the KAIWEETS KM401 4000 count DMM

I have the KM401. Based on what I've seen and heard, Kaiweets puts out some pretty decent meters in their price range. I also have their KM601S rechargeable "smart" meter. Their HT118A (6K count) and HT118E (20K count) meters gets rave reviews as well (Habotest sells the same models, not sure who the OEM is). Very similar if not the same as the Zoyi ZT-225 (25K count) meter I have. Speaking of the ZT-225, if you're looking for more cheap meter candidates to review/blow up, I'd like to see it tested. :)

What can I say, I collect (my wife would say "hoard") cheap and not-so-cheap meters. I think I'm up to just over 40 in the collection now.
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on March 18, 2024, 03:33:42 am
Transient Testing the KAIWEETS KM401 4000 count DMM

Only use genuine Kaiweets!

I know it isn't what you are testing, but wasn't that meter actually fairly inaccurate during some of your basic checks?  And what is with the TRMS not reading your half-wave source?  I noticed on the teardown that there isn't an AC coupling capacitor as far as I can see and the voltage divider must be done with those MELFs. 
Title: Re: Handheld meter robustness testing
Post by: bdunham7 on March 18, 2024, 03:34:24 am
(my wife would say "hoard")

She's right....
Title: Re: Handheld meter robustness testing
Post by: joeqsmith on March 19, 2024, 12:20:36 am
.... wasn't that meter actually fairly inaccurate during some of your basic checks? 

I never looked at what they spec but was surprised to see everything reading low.  Wasn't expected.   

And what is with the TRMS not reading your half-wave source? 

This particular meter doesn't offer manual range or I would have switched it.