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Are you interested in seeing more handheld meters tested?

This testing is pointless! Please STOP damaging these meters!
3 (6.5%)
 Yes, I would like to more meters tested.
43 (93.5%)

Total Members Voted: 46

Author Topic: Handheld meter electrical robustness testing.  (Read 494321 times)

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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2925 on: October 21, 2018, 01:54:35 am »
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.   
« Last Edit: October 21, 2018, 03:04:38 am by joeqsmith »
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2926 on: October 21, 2018, 02:43:44 am »
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 :(

« Last Edit: October 21, 2018, 02:48:19 am by malagas_on_fire »
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2927 on: October 21, 2018, 02:56:01 am »
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?
« Last Edit: October 21, 2018, 03:06:28 am by joeqsmith »
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2928 on: October 21, 2018, 03:03:22 am »
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. 
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2929 on: October 21, 2018, 03:16:13 am »
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
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2930 on: October 21, 2018, 05:34:47 am »
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=
« Last Edit: October 21, 2018, 05:36:23 am by malagas_on_fire »
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Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #2931 on: October 21, 2018, 06:11:38 am »
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.
« Last Edit: October 21, 2018, 06:16:05 am by bd139 »
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2932 on: October 21, 2018, 07:36:47 am »
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.   
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #2933 on: October 21, 2018, 07:49:06 am »
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.
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2934 on: October 21, 2018, 08:02:55 am »
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 ...



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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2935 on: October 21, 2018, 08:38:09 am »
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.
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #2936 on: October 21, 2018, 08:48:35 am »
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".
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2937 on: October 21, 2018, 09:03:48 am »
This video is for our long lost member True.   


How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #2938 on: October 21, 2018, 09:18:50 am »
I've actually got one of those. It's the "hamfest purchase testing meter". Will watch the video  :-+
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2939 on: October 21, 2018, 10:57:18 am »
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



« Last Edit: October 21, 2018, 11:01:53 am by malagas_on_fire »
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2940 on: October 21, 2018, 11:04:45 am »
The Keysight meter I ran also used spark gaps (GDTs) and it did not do very well in my tests. 
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2941 on: October 28, 2018, 02:42:04 am »
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
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2942 on: October 28, 2018, 03:07:03 am »
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.
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2943 on: October 28, 2018, 06:13:49 am »
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?
« Last Edit: October 28, 2018, 06:32:35 am by malagas_on_fire »
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Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2944 on: October 28, 2018, 08:57:46 am »
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?
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2945 on: October 28, 2018, 09:02:39 am »
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.   
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2946 on: October 28, 2018, 09:12:17 am »
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.   
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Online bd139

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Re: Handheld meter electrical robustness testing.
« Reply #2947 on: October 28, 2018, 09:38:52 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.
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2948 on: October 28, 2018, 10:18:04 am »
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.
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Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2949 on: October 28, 2018, 10:19:58 am »
Yes, you are missing something!! 
Uh... What exactly? The speed of the transient? I thought I had it covered on my post...
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 


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