Multimeter - Failures from real world use ? - Page 1
Forum section: electronics / testgear

author: lodkolven
author_rank: Contributor
timestamp: November 25, 2019, 07:23:45 pm
content: HiI'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... ;-)

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 25, 2019, 07:32:09 pm
content: 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.

author: ataradov
author_rank: Super Contributor
timestamp: November 25, 2019, 07:38:32 pm
content: 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.

author: Fungus
author_rank: Super Contributor
timestamp: November 25, 2019, 08:02:52 pm
content: 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.

author: AndyC_772
author_rank: Super Contributor
timestamp: November 25, 2019, 08:08:37 pm
content: 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.

author: Jeroen3
author_rank: Super Contributor
timestamp: November 25, 2019, 08:10:15 pm
content: Dropping the bag with meters in the ocean when transferring to pilot ship?

author: Marck
author_rank: Regular Contributor
timestamp: November 25, 2019, 09:03:31 pm
content: 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 177But that is all I know of apart from probes breakingM

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2019, 09:23:34 pm
content: 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

author: ataradov
author_rank: Super Contributor
timestamp: November 25, 2019, 09:28:48 pm
content: 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?

author: ejeffrey
author_rank: Super Contributor
timestamp: November 26, 2019, 12:01:16 am
content: 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 26, 2019, 12:26:35 am
content: Quote from: lodkolven on November 25, 2019, 07:23:45 pmWith 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."

author: maginnovision
author_rank: Super Contributor
timestamp: November 26, 2019, 12:50:40 am
content: 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).

author: Gregg
author_rank: Super Contributor
timestamp: November 26, 2019, 02:55:11 am
content: 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.

author: najrao
author_rank: Regular Contributor
timestamp: November 26, 2019, 08:26:36 am
content: 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!

author: Electro Detective
author_rank: Super Contributor
timestamp: November 26, 2019, 10:20:21 am
content: Multimeter ass@ssination 'tools':1. leaking batteries, any type, any brand,from dirt cheap, to overpriced names flogged with loads of BS circus styled marketing2. 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 markers5. Lending or hiring out the multimeter to 'measuring current = power measurement' taught imbeciles who are severely Volts/Amps/Ohms challenged= BEGGING FOR DRAMA6. 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..

author: Kean
author_rank: Unknown
timestamp: November 26, 2019, 10:27:36 am
content: Quote from: joeqsmith on November 26, 2019, 12:26:35 amI 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.

author: Fungus
author_rank: Super Contributor
timestamp: November 26, 2019, 10:34:56 am
content: Quote from: Electro Detective on November 26, 2019, 10:20:21 amGet a meter with no current measurement, eg a Fluke 101.Quote from: Electro Detective on November 26, 2019, 10:20:21 amSee (3).(or Just Say No.)

author: AndyC_772
author_rank: Super Contributor
timestamp: November 26, 2019, 10:41:24 am
content: 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.

author: Rerouter
author_rank: Super Contributor
timestamp: November 26, 2019, 11:05:30 am
content: 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)

author: Muttley Snickers
author_rank: Unknown
timestamp: November 26, 2019, 11:48:06 am
content: 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.

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 26, 2019, 11:56:56 am
content: Quote from: Kean on November 26, 2019, 10:27:36 amForgot 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 26, 2019, 01:03:00 pm
content: If I remember right we had a member try to measure the voltage on their electric flyswatter which damaged the meter.

author: dr.diesel
author_rank: Super Contributor
timestamp: November 26, 2019, 01:33:55 pm
content: 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!

author: Black Phoenix
author_rank: Super Contributor
timestamp: November 26, 2019, 02:46:47 pm
content: Quote from: dr.diesel on November 26, 2019, 01:33:55 pmThere is something I would love to see the end result...

author: dr.diesel
author_rank: Super Contributor
timestamp: November 26, 2019, 03:11:59 pm
content: Quote from: Black Phoenix on November 26, 2019, 02:46:47 pmNo 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.

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: November 26, 2019, 03:21:11 pm
content: Quote from: dr.diesel on November 26, 2019, 01:33:55 pmNext time, place a flux capacitor between it and the tower.

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: November 26, 2019, 03:29:25 pm
content: 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.

author: Fungus
author_rank: Super Contributor
timestamp: November 26, 2019, 05:11:36 pm
content: Quote from: Doom-the-Squirrel on November 26, 2019, 03:29:25 pmThat might be what's printed on the front, yes, but...Quote from: Doom-the-Squirrel on November 26, 2019, 03:29:25 pmLook 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.

author: AVGresponding
author_rank: Super Contributor
timestamp: November 26, 2019, 06:07:36 pm
content: Meter: UT60AFailure: LCDCause: Impact by combination pliers being thrown into the toolbag

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: November 26, 2019, 07:32:37 pm
content: Quote from: Fungus on November 26, 2019, 05:11:36 pmYes, 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.htmlAnd 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.

author: jfiresto
author_rank: Frequent Contributor
timestamp: November 26, 2019, 07:55:29 pm
content: 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.

author: DeepLink
author_rank: Regular Contributor
timestamp: November 26, 2019, 08:07:28 pm
content: Fluke 83 - Bad LCD (Rubber strips - had a few of those)Fluke 79 - Salt Water - DeadNo Name chinese DMMDropped - brokenDropped in Salt water - deadLeft in Rain - deadBattery leaking - Various resultsMy brother is keeping me busy with all those cheap DMMAll but the Fluke 83 was user errors

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: November 26, 2019, 10:34:26 pm
content: Quote from: DeepLink on November 26, 2019, 08:07:28 pmHow old was the Fluke 83?Just wondering if an LCD issue is something I might encounter in the future with my 88V

author: Electro Detective
author_rank: Super Contributor
timestamp: November 27, 2019, 10:50:52 pm
content: 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 tracksalso, 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 meAnother 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 terminalsi.e. I do all my turn ons, switching and meter wake ups with NO signals appliedand have had no drifts, no weird quirks, CAL still to spec, and no demises.. YETThat's my take and sticking to it, for financial reasons if anything elseOTOH if doing the 'no no' stuff above makes no difference to whether meters might fail or notand or I've just been lucky,I'm interested in what others may have experienced

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: November 28, 2019, 06:49:23 am
content: Trying to measure volts on the current range causes havoc.

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: November 28, 2019, 08:31:00 am
content: Quote from: nigelwright7557 on November 28, 2019, 06:49:23 amCry havoc! And...you know the rest.At least it is better than dividing by zero....

author: Electro Detective
author_rank: Super Contributor
timestamp: November 28, 2019, 08:50:43 am
content: Quote from: Doom-the-Squirrel on November 28, 2019, 08:31:00 amif you've avoided thehavoc!thingand 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

author: PA4TIM
author_rank: Super Contributor
timestamp: November 28, 2019, 08:58:27 am
content: 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+probesSo 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2019, 06:00:37 pm
content: Quote from: PA4TIM on November 28, 2019, 08:58:27 amIt 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2019, 06:46:08 pm
content: 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

author: Electro Detective
author_rank: Super Contributor
timestamp: November 30, 2019, 09:04:27 am
content: 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 boothi.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 crackedNote there is never mention of the leads and their condition during a major electronical snafu

author: joeqsmith
author_rank: Super Contributor
timestamp: November 30, 2019, 09:39:25 pm
content: Quote from: Electro Detective on November 30, 2019, 09:04:27 amIt'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.

author: james_s
author_rank: Super Contributor
timestamp: December 01, 2019, 12:47:35 am
content: 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 01, 2019, 04:52:03 am
content: Quote from: james_s on December 01, 2019, 12:47:35 amLOL, 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

author: james_s
author_rank: Super Contributor
timestamp: December 01, 2019, 05:52:56 am
content: Quote from: joeqsmith on December 01, 2019, 04:52:03 amI 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.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 01, 2019, 06:20:34 am
content: 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.

author: SeanB
author_rank: Super Contributor
timestamp: December 01, 2019, 07:03:07 am
content: 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.

author: DeepLink
author_rank: Regular Contributor
timestamp: December 01, 2019, 12:00:01 pm
content: Quote from: Doom-the-Squirrel on November 26, 2019, 10:34:26 pm20 years old modelSaw quite a few with this failureAll my newer Fluke are ok

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: December 01, 2019, 06:08:37 pm
content: Now there's one way to test a Fluke DMM.

author: james_s
author_rank: Super Contributor
timestamp: December 01, 2019, 09:18:40 pm
content: Quote from: joeqsmith on December 01, 2019, 06:20:34 amThe 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.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 01, 2019, 10:07:14 pm
content: I use multimeters in industrial settings all the time and don't recall seeing an actual failure, but I have a Fluke 289 that I broke the battery pack on. I've had several current mode fuses go, but not technically a meter failure. Now that I think about it though, I was a nuclear reactor operator on an aircraft carrier and part of the operator duties was electronic instrument maintenance. While performing calibration checks on a temperature instrument, one of our guys (not me, really) performed a voltage check with the leads plugged into the current sockets. The instrument lost it's mind and immediately dropped all the control rods to the bottom of the core. But the meter survived. The guy gave periodic training for the next year on proper multimeter operation. So, watch where you plug your probe(s). Bad things can happen.

author: james_s
author_rank: Super Contributor
timestamp: December 02, 2019, 12:51:19 am
content: I'll keep that in mind the next time I happen to be tinkering with a nuclear reactor

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: December 02, 2019, 05:01:30 am
content: Quote from: james_s on December 02, 2019, 12:51:19 amKeep us all informed, so I know when I need to relocate.

author: AVGresponding
author_rank: Super Contributor
timestamp: December 02, 2019, 06:31:31 pm
content: Quote from: SeanB on December 01, 2019, 07:03:07 amYes

author: SeanB
author_rank: Super Contributor
timestamp: December 02, 2019, 06:38:59 pm
content: Quote from: ThickPhilM on December 02, 2019, 06:31:31 pmyou definitely do not work at my metro then..........

author: AVGresponding
author_rank: Super Contributor
timestamp: December 02, 2019, 09:51:05 pm
content: Quote from: SeanB on December 02, 2019, 06:38:59 pmDon't get me wrong, there are people here I wouldn't trust to change a fluorescent tube, but on average I'd say we're on a par with any decent private contractor, and in fact better than any contractor that operates on price.Where we really fall down is in the management stakes; we're vastly top heavy with people that it wouldn't surprise you if you learned that their significant other has to tie their shoelaces in the morning.

author: rsjsouza
author_rank: Super Contributor
timestamp: December 02, 2019, 10:18:28 pm
content: I damaged my trusty 25 year-old Minipa ET2060 when measuring the turns ratio of a 9kv/30mA Neon Sign Transformer tied to a Variac to limit its output voltage to 1kV. All the tests went quite nice, but in a last minute brain fart I turned the knob a bit way too far and heard a loud "poof" from the meter.I wasn't very experienced at the time and condemned it, despite it could still measure things although with wonky values. But the temptation to replace it with a real Fluke 179 pushed it over the cliff. I shouldn't have done so - it was a great meter that would have probably given me 25 more years of good use.As Kean mentioned, nowadays I have gobs of portable, benchtop and clamp meters...

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: December 07, 2019, 04:48:29 pm
content: A story related to me by a trainer recently shows why it is always important to check the CAT rating.A technician was using a multimeter to check the batteries of an electric bus.The meter was not rated for such use, however.So, when the technician probed the batteries, the meter exploded. The technician required hospitalization.Not sure from the story if he lost just fingers or his entire hand.

author: ender4171
author_rank: Contributor
timestamp: December 11, 2019, 02:48:33 pm
content: I had a cheap Extech MN35 that I blew up once. Went to measure mains voltage with the probes in the current positions and POP. When I took it apart, not only was the fuse toast (obviously), but the solder on the input side of the current shunt was literally vaporized, along with a few mm of the shunt itself.

author: Doom-the-Squirrel
author_rank: Regular Contributor
timestamp: December 11, 2019, 04:38:53 pm
content: Quote from: ender4171 on December 11, 2019, 02:48:33 pmFor a moment, I thought this was a repeat of what Dave had happen to him with that Extech meter with the tweezers.That sounds like it was quite a bang you experienced there.

author: rsjsouza
author_rank: Super Contributor
timestamp: December 11, 2019, 04:56:20 pm
content: Quote from: ender4171 on December 11, 2019, 02:48:33 pmFuses can take a while to blow (several cycles), which will certainly increase the temperature at the weaker spots of the chain and eventually lead to burned traces and/or parts before the circuit becomes open.