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 electrical robustness testing.  (Read 503008 times)

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Offline IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2475 on: March 13, 2018, 02:53:08 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.
I'm not an EE--what am I doing here?
 

Online LazyJack

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Re: Handheld meter electrical robustness testing.
« Reply #2476 on: March 14, 2018, 01:25:04 am »
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?
 

Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2477 on: March 14, 2018, 01:46:43 am »
Re: The shield

Could the shield tabs pop out under vibration? Maybe give it a few whacks.

Seems like a long shot, but...  :popcorn:
« Last Edit: March 14, 2018, 08:44:45 am by Fungus »
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2478 on: March 14, 2018, 03:59:33 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.

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

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2479 on: March 15, 2018, 11:48:28 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

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

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2480 on: March 16, 2018, 05:52:23 am »
joeqsmith, I can't wait for the 87V tests.

BTW, nice doodles of the MOVs and Uni-T. :)
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...
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2481 on: March 17, 2018, 01:01:12 pm »
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
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline don.r

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Re: Handheld meter electrical robustness testing.
« Reply #2482 on: March 17, 2018, 03:51:00 pm »
Shocking how much better this rev is! Absolutely shocking! (see what I did there?)
Shippers: for the love of Pete and all that is holy, STOP USING UPS INTERNATIONAL!
 

Offline Towger

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Re: Handheld meter electrical robustness testing.
« Reply #2483 on: March 17, 2018, 08:03:48 pm »
The Fluke fan boys will be happy again.
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2484 on: March 18, 2018, 02:12:30 am »
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. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline jordanp123

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Re: Handheld meter electrical robustness testing.
« Reply #2485 on: March 18, 2018, 06:14:34 am »
Any details on what fluke changed with this PCB revision ? If thats already been posted, I apologize, I searched but didn't find it.
 
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Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2486 on: March 18, 2018, 07:06:49 am »
gold is soft and gets worn through pretty fast on things like pcb contacts for edge connectors.
maybe they used something harder.
 

Offline zaoka

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Re: Handheld meter electrical robustness testing.
« Reply #2487 on: March 19, 2018, 02:03:12 am »
Will installing better substitutes of BAV diodes improve protection circuit, if so what diode should be used?

Is it time for Fluke 28II ??  :-//
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2488 on: March 22, 2018, 11:10:20 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
« Last Edit: March 23, 2018, 10:09:35 am by joeqsmith »
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline kcbrown

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Handheld meter electrical robustness testing.
« Reply #2489 on: March 22, 2018, 04:39:38 pm »
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
« Last Edit: March 22, 2018, 04:41:23 pm by kcbrown »
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2490 on: March 23, 2018, 02:25:23 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 views to decide if you want to see it. 

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. 
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...
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2491 on: March 23, 2018, 10:51:52 am »
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.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #2492 on: March 23, 2018, 11:23:06 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 -(a-jbc-killer-at-$239)/

Back to regular programming folks! Sorry!
« Last Edit: March 23, 2018, 06:55:18 pm by Simon »
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2493 on: March 25, 2018, 01:09:08 am »
The video for the remaining tests of the Fluke 87V are now on-line.   Enjoy. 

https://youtu.be/dQPcAs0EEqY
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2494 on: March 25, 2018, 11:25:45 am »
The HIOKI handheld meter I previously tested uses a similar design.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2495 on: March 25, 2018, 11:35:43 am »
The HIOKI handheld meter I previously tested uses a similar design.

Torture it on the rack!
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2496 on: March 25, 2018, 01:55:52 pm »
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. 

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

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2497 on: March 28, 2018, 01:03:16 pm »
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?     
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2498 on: March 28, 2018, 05:17:10 pm »
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.

 

Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2499 on: March 28, 2018, 08:57:36 pm »
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.
 


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