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 509317 times)

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Offline tautech

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Re: Handheld meter electrical robustness testing.
« Reply #2500 on: March 28, 2018, 09:03:39 pm »
Are you sure it was the resistors smoking Joe and not the Mexican fuses about having to contribute to building the border wall ?  >:D
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Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2501 on: March 29, 2018, 01:29:19 am »
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 is quite similar in physical appearance.
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2502 on: March 29, 2018, 12:14:26 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.

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

Offline mzacharias

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Re: Handheld meter electrical robustness testing.
« Reply #2503 on: March 30, 2018, 11:18:55 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.
« Last Edit: March 31, 2018, 12:43:07 am by mzacharias »
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2504 on: March 31, 2018, 01:08:58 am »
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. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline mzacharias

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Re: Handheld meter electrical robustness testing.
« Reply #2505 on: March 31, 2018, 04:45:17 am »
OK.
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2506 on: March 31, 2018, 03:47:17 pm »
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. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2507 on: April 01, 2018, 07:42:30 am »
Running tests on the older Fluke 87V. 

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

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Re: Handheld meter electrical robustness testing.
« Reply #2508 on: April 03, 2018, 05:58:24 am »
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.



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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2509 on: April 03, 2018, 08:25:01 am »
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.   
« Last Edit: April 03, 2018, 09:49:25 am by joeqsmith »
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Offline ChrisLX200

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Re: Handheld meter electrical robustness testing.
« Reply #2510 on: April 03, 2018, 09:53:25 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 :)
 
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2511 on: April 03, 2018, 10:26:51 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.     
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2512 on: April 03, 2018, 12:09:20 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.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline ChrisLX200

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Re: Handheld meter electrical robustness testing.
« Reply #2513 on: April 03, 2018, 03:54:36 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.
« Last Edit: April 03, 2018, 04:10:10 pm by ChrisLX200 »
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2514 on: April 04, 2018, 02:23:51 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.
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.
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2515 on: April 04, 2018, 02:49:57 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.
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.
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2516 on: April 04, 2018, 03:00:03 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.


Fact
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2. something known to exist or to have happened:
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3. a truth known by actual experience or observation; something known to be true:
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...
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Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2517 on: April 04, 2018, 03:24:31 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.
 

Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2518 on: April 04, 2018, 10:47:57 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.
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2519 on: April 16, 2018, 04:36:18 am »
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
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2520 on: April 16, 2018, 09:39:01 am »
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.

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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2521 on: May 05, 2018, 11:13:29 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.. 
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Offline tautech

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Re: Handheld meter electrical robustness testing.
« Reply #2522 on: May 05, 2018, 12:49:10 pm »
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.
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Online joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2523 on: May 06, 2018, 03:07:41 am »
Poor Flukes.  Like any other meter, they always have to earn my respect.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline MacMeter

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Re: Handheld meter electrical robustness testing.
« Reply #2524 on: May 06, 2018, 06:24:32 am »
Looks like it tried to escape you, LOCKED in the Panavise now! :)
 


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