Poll

Are you interested in seeing more handheld meters tested?

This testing is pointless! Please STOP damaging these meters!
3 (6.4%)
 Yes, I would like to more meters tested.
44 (93.6%)

Total Members Voted: 47

Author Topic: Handheld meter robustness testing  (Read 648738 times)

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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2775 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.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2776 on: August 26, 2018, 10:03:49 pm »
Wow... If the fault description is accurate with what actually happened in this thread, I propose to add a new test to your mix: EPV (Extremely Puny Voltage) breakdown test.
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...
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2777 on: August 26, 2018, 11:09:27 pm »
Wow... If the fault description is accurate with what actually happened in this thread, 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. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2778 on: August 27, 2018, 12:38:57 am »
Wow... If the fault description is accurate with what actually happened in this thread, 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.
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...
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2779 on: August 27, 2018, 10:46:27 pm »
Hammer vs the Fluke 189.  Hammer wins.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2780 on: August 27, 2018, 11:34:19 pm »
Hammer vs the Fluke 189.  Hammer wins.
What the...?!?
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...
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2781 on: August 27, 2018, 11:44:16 pm »
It was way beyond wet sanding.   :-DD
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2782 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.
I'm not an EE--what am I doing here?
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2783 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.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2784 on: August 28, 2018, 02:08:01 am »
Cut some Lexsand on a bandsaw and hand cut the lips into it.  Needs some glue
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2785 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...
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2786 on: August 28, 2018, 11:27:08 am »
At least the display can be read now.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2787 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??
 

Offline true

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Re: Handheld meter electrical robustness testing.
« Reply #2788 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.
 

Offline retiredcaps

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Re: Handheld meter electrical robustness testing.
« Reply #2789 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?
 

Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2790 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
 

Offline true

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Re: Handheld meter electrical robustness testing.
« Reply #2791 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.
 

Offline joseph nicholas

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Re: Handheld meter electrical robustness testing.
« Reply #2792 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. 
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2793 on: August 31, 2018, 11:48:00 am »
Applying 1KVDC to various surface mount resistors 

https://youtu.be/8Zl2HJ5qo_4
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2794 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

If one can make knowledge flow than it will go from negative to positve , for real
 

Offline true

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Re: Handheld meter electrical robustness testing.
« Reply #2795 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.
 

Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2796 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.


 
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Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2797 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?

If one can make knowledge flow than it will go from negative to positve , for real
 

Offline true

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Re: Handheld meter electrical robustness testing.
« Reply #2798 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?
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2799 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. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 


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