Multimeter - Failures from real world use ?

[lodkolven]

Hi
I've been reading up on Joe Smiths extensive multimeter tests, they are really informative and educational, a question started to grow about some missing information back in my head along the way, what does the real world use of these meters tell us about how and how often do they actually fail?

So what i'm really interested in is the real numbers/facts about how/why meters do fail when used by the forum users?

Please chime in with your own multimeter fails, please describe type of use when failed and brand/model of the meter.

It would be especially interesting to see how real world fails correlates to Mr Smiths test results... ;-)

[shakalnokturn]

I don't hang around with people who do industrial and other dangerous measurements daily.
Luckily or not, from what I've seen handheld multimeter's fail mainly of:

-Battery leak.
-Exterior liquid spillage.
-Worn rotary switch.
-User using the meter to measure it's own battery voltage.
-Physical wreckage.

Edit: None of which have failed while I was using them. Failures I have seen and sometimes repaired.

[ataradov]

There are two main categories of uses that call for vastly different designs -  professionals working with high energy circuits and hobbyists.

"Professionals" here is important because of continuous use and meter being subjected to repeated stress. This is essentially the only use that really justifies better protection on the multimeter.

For hobby use, I personally would not have any issues "measuring mains" with a $3 cheapie once in a while following normal precautions. Obviously everyone decides for themselves.

And for low energy hobby use none of that matters at all. Realistically the most damage you will be able to do to the meter is blow the fuse. And that's the most damage I was able to do personally.

[Fungus]

If any of my meters have failed it's been because of the range switches developing bad contacts, but I mostly do low voltage DC.

I know a guy who works in a factory. He killed a meter two weeks ago by connecting it to 380V AC in continuity mode. Horses for courses.

[AndyC_772]

Don't forget the professionals who use the meter in low energy applications. I'd venture to suggest that's most of us, and our multimeters (like our fingers, scope probes and other things we routinely poke into our projects) endure virtually no electrical stress for their entire lives.

I measure voltage levels <50V and currents <500mA every day, and I need a multimeter which is accurate and reliable, but not necessarily electrically robust.

FWIW my Fluke 289 went in for repair a couple of weeks ago - it had excessive offset on the AC current ranges. I've no idea why, but maybe it has something to do with this model's well known internal battery issues? A little electrolyte leakage might explain it.

[Jeroen3]

Dropping the bag with meters in the ocean when transferring to pilot ship?

[Marck]

To be honest in 20 years I have never had a meter go faulty.  Currently I am not certain of the location of a few meters.

My father had a battery spring snap on a brand new fluke about 10 years ago.
And I blew an internal fuse on a 177

But that is all I know of apart from probes breaking

M

[CDaniel]

Working with the meter at job is completely another level for responsability and possible mistakes than hobby , maybe it's hard to understand until you are in this position 

[ataradov]

Define "job". I work with multimeters daily on the office on low voltage boards. I don't feel like it is a huge responsibility.

I your job is actually working with high energy stuff, then sure. But how many people selecting multimeter by watching a YT video are in this category?

[ejeffrey]

I once destroyed a multimeter by hooking it up to mains (230 V / 16A) while connected to the current jacks.  This meter had an unfused 10A/20A range.  The housing contained the blast and the circuit breaker did its job, so there was no injury but I wouldn't want to do that again.

Other than that, I have seen a few mechanically damaged or damaged by leaking battery.

[joeqsmith]

Hi
I've been reading up on Joe Smiths extensive multimeter tests, they are really informative and educational, a question started to grow about some missing information back in my head along the way, what does the real world use of these meters tell us about how and how often do they actually fail?

So what i'm really interested in is the real numbers/facts about how/why meters do fail when used by the forum users?

Please chime in with your own multimeter fails, please describe type of use when failed and brand/model of the meter.

It would be especially interesting to see how real world fails correlates to Mr Smiths test results... ;-)

With the number of meters sold, I doubt many buyers are on this forum.    Of the small percentage that are, I doubt many of them would post.  That said, I damaged my first meter several times.  Basically, from being young and stupid.   

When I was older and a little better educated, I manged to damage my new Fluke meter a few times from small transients while experimenting.   These were very expensive mistakes.  I bought a cheap 830 that I cracked the LCD.   The switch went out in my BK.    Loaned out my CEM and the person turned the switch past the dead stop.   I have an HP34401A bench meter that must be going on at least 25 years old now.   When one of our trees was struck by lightning, it put a transient into the house that took out the meter's GPIB controller.   

A few years ago,  friends and I bought maybe 10 of the UNI-T UT210E clamp meters.  So far, two of them have had the switch start to go bad.  These are ones that are actually seeing some use.   

I have had people write me about things they have done to damage their meters.   These included, measuring the output from a high voltage electric fence supply, measuring a grill starter similar to what I use in my testing,  measuring the HV side of an ignition coil.   A member on this site damaged their new 121GW with HV but I am not sure we ever found out the specifics.  Maybe they will chime in.   A few people have measured the current of the mains and posted pictures.     

***
Thought I should add, one was measuring the electronic gas grill igniter for a cooktop range. 
***

I posted once about a friend who is a retired master electrician.   He told me how he never saw the need for PPE.  One day they had to make some measurements and suited up.  Two people go in.  Friend is holding the meter, man in front has the probe sticks (I understand these were several feet long).    Probes were attached and the meter explodes.  He figured the PPE save him that day.   Of course, this required a fair bit of paperwork and the meter with probes were returned for a failure analysis.   While the team that went in were initially blamed, turned out the brand new meter had a fault. 

My all time favorite was a Fluke 189 where "The 20KV came from a power supply that drives the final anode on the CRT HUD of the Typhoon Eurofighter."

[maginnovision]

For my meters they've typically died from falls, maybe concrete, maybe into water, maybe in oil or gas. I had one die because I'd soldered a thick wires across fuse while waiting for a new one to show up. Someone borrowed it and I didn't know and they ended up melting it a bit(about 360V DC and maybe 12-15 amps through it). Every cheapo Chinese meter except the an8008 has died measuring things like mains going to compressors, or other motors in the 120-300V range.

Haven't had one die in years because I typically buy tougher meters now(other than Chinese ones).

[Gregg]

About 25 years ago I bought an Amprobe AM-90 (or maybe it was an AM-91) multimeter because it had a fast crest capture and was cheaper than a comparable Fluke.  I was working on large DC machinery in the 5 to 50 horsepower range with big scary open contacts at the time as well as lots of 480 volt stuff.  Expensive mistake; it went wonky shortly after the warranty was up.  I tried all of the usual cleaning of contacts and looking for bad solder joints to no avail.  It may have been victim of an inductive spike, but it never was dropped or wet.  I couldn’t trust it and purchased a Fluke 89-IV which has been a faithful companion ever since.

[najrao]

Long time ago, I killed an autoranging dmm. Was connected to a variac primary (230V), and the variac output was open. The ass me switched off the variac by a fast acting switch. The stored energy of the magnetizing inductance got dumped into the dmm. Its main chip input died, and could not be revived. It still worked on ranges other than ac volts. The input protection, what there was of it, did nothing, and remained in tact.

One learns!

[Electro Detective]

Multimeter ass@ssination 'tools':

1. leaking batteries, any type, any brand,
from dirt cheap, to overpriced names flogged with loads of BS circus styled marketing

2. please see 1.

3. leads plugged into the current inputs and voltage measurements 'attempted'
i.e. cover the current inputs with tape FOREVER,
till further notice and  'how to and why' from friendly neighborhood EEVblog members !

4. drops, bumps, direct sunlight,
male cat pee territory markers 

5. Lending or hiring out the multimeter to 'measuring current = power measurement' taught imbeciles who are severely Volts/Amps/Ohms  challenged
= BEGGING FOR DRAMA 

6. using it to prop up a heavy CRO during a recap and surprise earthquake,
using it as a car wheel choc, 
or zombie bashing during the next apocalypse, assuming the last one is officially over.. 

[Kean]

A member on this site damaged their new 121GW with HV but I am not sure we ever found out the specifics.  Maybe they will chime in.

I think Joe may be referring to me.  I damaged my 121GW about a year ago now by measuring the output of an ultrasonic driver without thinking.  That driver output was something like 1.2kV at 40kHZ.  I was under pressure to get a project finished and delivered to an interstate client, and I would have just put the meter aside when I realised I needed to use a HV probe for the measurement.

On my return a few weeks later I noticed the meter was acting very strange, like reading 12V on a 5V supply.  I reported this fault in one of the threads here, but only realised some time later the abuse I had subjected it to.  I opened it up and found the damage (a burnt spot near the range switch).  Cleaned it up and all was good again, and in good calibration.  While it isn't my one of my go-to meters, I do use it somewhat regularly and haven't had any further issues.

ISTR having a broken 2mm input jack on one of my early Micronta meters.  Other than that, I think all my other DMM failures have been caused by battery leaks.  I'd guess that is 3 or so that have gone to DMM heaven, and I've probably only blown a few DMM fuses in my 35-odd years of electronics work.

I currently have about ten bench meters (5.5 or 6.5 digit), about a dozen handheld ones, and another ten clamp meters.

[Fungus]

3. leads plugged into the current inputs and voltage measurements 'attempted'
i.e. cover the current inputs with tape FOREVER,
till further notice and  'how to and why' from friendly neighborhood EEVblog members !

Get a meter with no current measurement, eg a Fluke 101.

5. Lending or hiring out the multimeter to 'measuring current = power measurement' taught imbeciles who are severely Volts/Amps/Ohms  challenged
= BEGGING FOR DRAMA 

See (3).

(or Just Say No.)

[AndyC_772]

You've reminded me that I did blow a DMM fuse about 6 or 7 years ago, while trying to track down a bad RAM chip in a Tektronix TDS754D.

I knew the memory address that was bad, but not which physical device it corresponded to, so the plan was to disable chips individually by disabling their chip select lines, one at a time, and see which locations gave errors on self-test.

IIRC the parts in question have dual chip selects (or some other logic which could be used to disable them - I forget the exact details). Fortunately, on the Tek, there was a nice, easily removed pull-up resistor between the CS pin and the power rail.

So I removed the resistor, put my DMM into current mode, and used it to short the now disconnected pin to ground.

Only: it turns out the pin wasn't disconnected. It was still connected to the power rail. My poor DMM got the entire supply current of which a TDS754D PSU is capable - and that's a lot. Bye bye 400mA fuse, obviously.

I never figured out why the Tek was designed this way. It literally had a "pull-up" resistor between +5V and +5V, next to an unused chip select pin on each memory device.

[Rerouter]

abusing the ohms range can do some odd things to multimeters,

E.g. measuring resistance in the wrong part of a circuit caused it to start up a switch mode driver via a protection diode back to the input, which happily gave it a kick well outside what it was rated for, also made the mV range faulty after that.

I still have a tried and true fluke meter that still works, but the range switch stops have broken off, so I can rotate the thing 360, weirdly enough 2 clicks counter-clockwise past the stop ends up measuring the battery voltage of the device (crudely)

[Muttley Snickers]

1. Unfused Fluke 75 in current mode across two phases whilst tracing a contactor fault on a customers timber processing machine, distracted by the customer for a second and bang.   

2. CEM DT-922 in voltage mode across the primary of a 12V-8A transformer whilst applying 240V to the secondary. My mistake on the primary and secondary wiring label.   

[shakalnokturn]

ISTR having a broken 2mm input jack on one of my early Micronta meters.

Forgot that on my list, have seen a couple too, one of them was a Fluke 83 (version forgotten).
Some Flukes have a bloody poor design for input banana physical resistance IMHO.

[joeqsmith]

If I remember right we had a member try to measure the voltage on their electric flyswatter which damaged the meter.

[dr.diesel]

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!

[Black Phoenix]

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!

There is something I would love to see the end result...

[dr.diesel]

There is something I would love to see the end result...

No visible by the eye damage.  I didn't put much effort into diagnosis, wasn't a fan of the meter, power supply section was ok, didn't dig past that.