Multimeter - Failures from real world use ?

[Doom-the-Squirrel]

I lost a Fluke 289 at a tower site that was truck by lightning.  Meter was logging ground potential between two buildings when a 2 minute "unscheduled" storm blew through!

Next time, place a flux capacitor between it and the tower. 

[Doom-the-Squirrel]

Though I haven't had any of my meters fail from use (Fluke quality!), I've seen it happen to others.

A coworker of mine had bought a multimeter from the Matco tool truck.
Not sure what the actual brand was. It just had their name on it.
I believe it was this one: https://www.matcotools.com/catalog/product/MD251/MATCO-BASIC-MULTIMETER/

A few months later, the thing failed on him while measuring resistance on an ignition coil.
The display was nonsensical.


On another occasion, I was with my parents.
My dad was using one of those cheap multimeters from Harbor Freight to measure mains.
You know the type; the one that costs less than $10 USD. Dave took one apart in mailbag.
The thing kept displaying nonsensical numbers. And it failed just from being in regular storage.
He used another cheap one to replace it.
He later was going to measure at a mains fuse block with the thing. I advised him not to, given that they're only rated Cat 2, 250 VAC.

I need to make it a point to get him a real quality meter.

[Fungus]

He later was going to measure at a mains fuse block with the thing. I advised him not to, given that they're only rated Cat 2, 250 VAC.

That might be what's printed on the front, yes, but...

I need to make it a point to get him a real quality meter.

Look at the Fluke 101. They're only about $45 delivered, they don't have any "dangerous" modes, Joe hasn't managed to hurt one with any of his tests.

[AVGresponding]

Meter: UT60A

Failure: LCD

Cause: Impact by combination pliers being thrown into the toolbag   

[Doom-the-Squirrel]

He later was going to measure at a mains fuse block with the thing. I advised him not to, given that they're only rated Cat 2, 250 VAC.

That might be what's printed on the front, yes, but...

I need to make it a point to get him a real quality meter.

Look at the Fluke 101. They're only about $45 delivered, they don't have any "dangerous" modes, Joe hasn't managed to hurt one with any of his tests.

Yes, I know Dave said meters like those should not be used on mains.
https://www.harborfreight.com/electrical/electrician-s-tools/7-function-digital-multimeter-63759.html

And I agree with that!

I'll have to find one of those. I assume the Fluke 101 is an older model?

I also figure a Klein Tools multimeter is a good choice too.

[jfiresto]

I had the temperature ranges fail on a B&K Precision 390A multi-meter after a couple years and perhaps a hundred hours use. They acted as if there was no connected thermocouple. Some curious white residue between all the SMDs pins may have had something to do with that.

B&K was very efficient and helpful. They replaced the Monday meter with a new one, plus another set of the originally included accessories.

[DeepLink]

Fluke 83 - Bad LCD (Rubber strips - had a few of those)
Fluke 79 - Salt Water - Dead

No Name chinese DMM
Dropped - broken
Dropped in Salt water - dead
Left in Rain - dead
Battery leaking - Various results

My brother is keeping me busy with all those cheap DMM

All but the Fluke 83 was user errors

[Doom-the-Squirrel]

Fluke 83 - Bad LCD (Rubber strips - had a few of those)
Fluke 79 - Salt Water - Dead

No Name chinese DMM
Dropped - broken
Dropped in Salt water - dead
Left in Rain - dead
Battery leaking - Various results

My brother is keeping me busy with all those cheap DMM

All but the Fluke 83 was user errors

How old was the Fluke 83?
Just wondering if an LCD issue is something I might encounter in the future with my 88V

[Electro Detective]

I missed mentioning this earlier in my meter ass@ssination blab, because I don't/won't do it PERIOD, so it's not in my 'remember' list. 

Now I don't know for sure about this, even though I see just about everyone on Youtube in last few years doing it.. 

Selecting meter modes, and or skipping through -no go- ones, whist signal is applied, can't be doing any multimeter any favors,
much less increasing ones productivity by decreasing the meter's internal input integrity and sparking the selector tracks

also, turning on a meter that needs a second or two to 'boot up' or get into gear, with large/er signal/s applied (120/240 AC volts or kickass DC cap voltages) does not seem right to me 


Another one is when a meter goes into a standby/sleep state, and the manufacturer states in the manual that switching to another range and back to the required mode 'wakes up the meter',
or by simply turning the meter off and on again. 

They fail to mention whether signal should still be applied or not    =

All the above does not sit right with me and I've had no problems ** with any meter EVER,
especially the dramas reported by EEVblog members,

**excluding crusty input sockets, leads plugs and probes,
and the usual suspects > faulty or leaking batteries, and ~loose~ 9 volt battery terminals

i.e. I do all my turn ons, switching and meter wake ups with NO signals applied
and have had no drifts, no weird quirks, CAL still to spec, and no demises.. YET   

That's my take and sticking to it, for financial reasons if anything else   

OTOH if doing the 'no no' stuff above makes no difference to whether meters might fail or not
and or I've just been lucky,
I'm interested in what others may have experienced 

[nigelwright7557]

Trying to measure volts on the current range causes havoc.

[Doom-the-Squirrel]

Trying to measure volts on the current range causes havoc.

Cry havoc! And...you know the rest.

At least it is better than dividing by zero....

[Electro Detective]

Trying to measure volts on the current range causes havoc.

Cry havoc! And...you know the rest.

At least it is better than dividing by zero....

if you've avoided the havoc! thing   and own a Fluke or other multimeter fitted with HRC fuses,
it's time to busk on the streets and or car boot sale to earn some cash to buy replacements 

[PA4TIM]

I had a Fluke 192 in for repair, both scope inputs toast. Turned out he used it to measure the high voltage side of a car ignition coil. First channel A, hmm, no output, lets try channel B, also nothing.......to bad for him the meter was beyond economical repair (at least 4 dead asics)

Killed a 1 MHz Voltcraft scope meter (13 years ago) by measuring 1200Vdc in the 1000V range (powersupply was supposed to give only 600V) everything in the meter was dead, several opamps with holes, evaporate traces, powersupply parts, even de display was dead. I was glad I did not had it in my hand. ) That was the first and last time I bought a B-brand meter.  My Brymen 869S survived 1400Vdc in VDC mode, and 230Vac  in resistance mode without a problem. I always check the meter before connecting the probes to the DUT but I often use several meters at the same time and in the case of the 230 vs resistance fault I took the wrong testlead+probes  So the overload was not a few seconds, it took a while before I noticed.
The 869S survived but the potential dangerous part was that I thought there was no 230V on the DUT.

[joeqsmith]

I had a Fluke 192 in for repair, both scope inputs toast. Turned out he used it to measure the high voltage side of a car ignition coil. First channel A, hmm, no output, lets try channel B, also nothing.......to bad for him the meter was beyond economical repair (at least 4 dead asics)

 

It does seem that I'm not the only one playing around with low energy sources with enough voltage to damage a meter.  Some of the sources mentioned, like the ignition coil output would be difficult to protect against.   I made a few videos to attempt to demonstrate what may have happened with Kean's 121GW, using a fairly low voltage DC source with higher currents.   This is also something I would doubt any handheld meter would survive.   

I would expect meters that have performed well against my tests,  to survive some of the other conditions mentioned but it's a difficult thing to quantify.  Outside of 61326 there really are no standards that I am aware of when it comes to how electrically robust a meter is.   

One thing that is clear is there is a big difference between brands when it comes to how robust they are.  Once we start looking at levels beyond 6KV, I can count the brands that have survived on one hand, Brymen, Fluke, Gossen and HIOKI.

[joeqsmith]

Video from Fluke starting at their safety testing.   Just slightly more energy than I use.   Slightly being an understatement.       Is that a UEi meter at 18:00?

https://youtu.be/IzwN8yibjjA?t=985

[Electro Detective]

I'd like to see their meters, and competitors offerings, with aged and or cracked screw posts, contain all those joules and flames,
without shrapnel spattering all over that secure testing booth

i.e. when a properly CAT rated multimeter is new out of the box, those fault (idiot) tests are believable.

but good luck once plastics age and or the posts are cracked

Note there is never mention of the leads and their condition during a major electronical snafu 

[joeqsmith]

I'd like to see their meters, and competitors offerings, with aged and or cracked screw posts, contain all those joules and flames,
without shrapnel spattering all over that secure testing booth

i.e. when a properly CAT rated multimeter is new out of the box, those fault (idiot) tests are believable.

but good luck once plastics age and or the posts are cracked

Note there is never mention of the leads and their condition during a major electronical snafu 

It's a good question but not working in that industry, I really don't know.   You could ask Dave as he may have the inside scoop on some of your questions.

I think you would have to find some old damaged meters and pay to have it ran.   Outside of the entertainment, I'm not sure what you would learn.    These tests are part of the validation.   To maintain the cert, you are supposed to have the products evaluated over time, but it's always with the latest production hardware.   Its hard to imagine anyone would use a meter in a high risk environment that had been damaged.

61010 does call for standard test leads for some of the tests.   I think the only time that the standard leads are not used is in the case where the meter had leads that are permanently attached, for example some pocket meters.   I am not sure if the companies are required to send in the meter with the leads they plan to use.   If they do, they are used for some of the tests but I am not sure if it's required.   In the case where the leads are bought from another supplier, they may count on that companies cert.   

[james_s]

I once damaged a Fluke 79 using it to measure the secondary current of a MOT, meter was sitting on an insulated pad, I forget what the load was, some kind of discharge lamp I think, primary on a variac with an incandescent ballast lamp. I'm not entirely sure why the meter failed but it turned out a 1k (IIRC) resistor had gone open circuit, I fixed it some time later and it still works.

[joeqsmith]

I once damaged a Fluke 79 using it to measure the secondary current of a MOT, meter was sitting on an insulated pad, I forget what the load was, some kind of discharge lamp I think, primary on a variac with an incandescent ballast lamp. I'm not entirely sure why the meter failed but it turned out a 1k (IIRC) resistor had gone open circuit, I fixed it some time later and it still works.

LOL, how could I forget all the MOT stories. I think this is the first time I have heard someone damage their meter trying to measure the current.  Normally they try to measure the output voltage and get a surprise that way.   

About 1 minute in, they appear to have their leads but it looks like maybe the probe ends are cut off so the leads are fairly short and the wires attach to some sort of binding post.   
https://www.fluke.com/en-us/learn/best-practices/safety/electrical-measurement-safety-videos/design-and-test-standards

[james_s]

LOL, how could I forget all the MOT stories. I think this is the first time I have heard someone damage their meter trying to measure the current.  Normally they try to measure the output voltage and get a surprise that way.   

I was measuring the current properly, with the meter in series with the load. I'm not really sure what caused the resistor to fail, maybe capacitive coupling between one of the test leads and ground? It was quite a few years ago now but I was being fairly careful, as careful as one can be abusing MOTs.

[joeqsmith]

Quick glance on Google for a schematic, looks like the 79 has the basic bridge with a zener for a clamp.  Then a 10 ohm shunt.   If the fuse, zener and shunt were the only things damaged, I would say you got lucky.   The 61010 standard does call out an open fuse DC test.  I think this is 2X over the max rating for the meter.  The 79 looks like it has a 700V range so maybe 1400V.   This test is performed with an open fuse.  If your fuse opened, putting 2KV across the meter with a MOT, depending on your load could be much worse than the test I run.

[SeanB]

I saw a Fluke 77, at the authorised supplier for me, RTC, that had been returned by the Metro engineering services as "faulty". On being opened all you could see inside the case was a nice new copper plating on both inner halves, and the main board was missing every track below the range switch top, except around component landings, with the solder mask also missing along the traces. Both fuses were perfect and intact, but the meter itself was totally dead for some reason. Turns out some clueless council worker (is there any other type) tried to use this meter to measure the primary side of a powered on LV transformer, because it was "autoranging". Leads did not look too good either, but I suspect that was something that was there before the incident, as the probes were missing, and replaced with bare wire ends, and arc marks.

[DeepLink]

Fluke 83 - Bad LCD (Rubber strips - had a few of those)
Fluke 79 - Salt Water - Dead

No Name chinese DMM
Dropped - broken
Dropped in Salt water - dead
Left in Rain - dead
Battery leaking - Various results

My brother is keeping me busy with all those cheap DMM

All but the Fluke 83 was user errors

How old was the Fluke 83?
Just wondering if an LCD issue is something I might encounter in the future with my 88V

20 years old model
Saw quite a few with this failure
All my newer Fluke are ok

[Doom-the-Squirrel]

Now there's one way to test a Fluke DMM.

[james_s]

Quick glance on Google for a schematic, looks like the 79 has the basic bridge with a zener for a clamp.  Then a 10 ohm shunt.   If the fuse, zener and shunt were the only things damaged, I would say you got lucky.   The 61010 standard does call out an open fuse DC test.  I think this is 2X over the max rating for the meter.  The 79 looks like it has a 700V range so maybe 1400V.   This test is performed with an open fuse.  If your fuse opened, putting 2KV across the meter with a MOT, depending on your load could be much worse than the test I run.

The fuse, zener and shunt were all fine, the only damage that occurred is a resistor opened up, and it wasn't the shunt. I think I was using the 10A mode, this was the output of a MOT so potentially quite a lot of current.