Poll

Which meter should be ran to celebrate 2000 subscribers?

Dave's new 121GW
58 (55.8%)
Gossen Metrawatt (you pick)
14 (13.5%)
HIOKI DT4282
6 (5.8%)
Anything but UNI-T (you pick)
1 (1%)
Anything made by UNI-T (you pick)
7 (6.7%)
I think the Fluke 87V is really a good meter and want to see if a third one would be better
10 (9.6%)
This testing is pointless! Please STOP damaging these meters!
8 (7.7%)

Total Members Voted: 103

Author Topic: Handheld meter electrical robustness testing.  (Read 396997 times)

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Offline joeqsmith

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Re: Hear kitty kitty kitty, nope not that kind of cat
« Reply #25 on: June 12, 2015, 06:57:55 am »
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


How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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The Cen-Tech P98674 (re-branded Mastech MS8229).       

http://www.youtube.com/watch?v=zzQ57h2vGV0&feature=youtu.be
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline ivan747

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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.
« Last Edit: June 14, 2015, 12:42:04 pm by ivan747 »
Nothing like the smell of rosin core solder in the morning.
"Could you not use some of that crowdfunded $1.5 million to hire a graphic designer who understands perspective?" -Delta
"A soldering station I bought once had a sticker on it that said, I shit you not, 'QENUINE'." -c4757p
 

Offline joeqsmith

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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. 
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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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.   
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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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. 
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline ivan747

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You're telling me that the Mastech/Cen-tech meter only required recalibration?
Nothing like the smell of rosin core solder in the morning.
"Could you not use some of that crowdfunded $1.5 million to hire a graphic designer who understands perspective?" -Delta
"A soldering station I bought once had a sticker on it that said, I shit you not, 'QENUINE'." -c4757p
 

Offline ivan747

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It sounds like the 28 II may be more robust than the 87V.

I have heard it is.
Nothing like the smell of rosin core solder in the morning.
"Could you not use some of that crowdfunded $1.5 million to hire a graphic designer who understands perspective?" -Delta
"A soldering station I bought once had a sticker on it that said, I shit you not, 'QENUINE'." -c4757p
 

Offline retiredcaps

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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
 

Offline Fungus

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Re: Hear kitty kitty kitty, nope not that kind of cat
« Reply #34 on: June 16, 2015, 05:42:57 pm »
Dave hates (feline) cats.
I vote we start sending him cat-related items in the mail.

 

Offline SeanB

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Re: Hear kitty kitty kitty, nope not that kind of cat
« Reply #35 on: June 16, 2015, 06:35:56 pm »
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......
 

Online tautech

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Muttley's close, he could send Dave a cat, bugger the litter.  :-DD
Avid Rabid Hobbyist & NZ Siglent Distributor
 

Offline Fungus

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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.
 

Offline SeanB

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Offline mtdoc

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Perhaps a boook....

 

Offline joeqsmith

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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

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.   
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline amyk

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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.
 

Offline retiredcaps

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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.
 

Offline retiredcaps

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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



 

Offline joeqsmith

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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
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Lightages

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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.
 

Offline joeqsmith

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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.   

How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Let the games begin.    A few friends wanted in on the fun and donated their meters.  The one is actually CAT III 600.   
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Lightages

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You have been asked a couple of times if you will share the schematic of your pulse generator. Will you please?
 

Offline Halvmand

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So the fluke did not even meet cat-I, or are you saving the best for last?
« Last Edit: June 19, 2015, 01:27:46 am by Halvmand »
 


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