Handheld meter robustness testing

[joeqsmith]

It has anti high voltage 

 

[mqsaharan]

Run UT60EU or UT60BT. It has a full set of basic functions. If it is robust enough, it could be a good choice for a beginner DMM.
https://www.amazon.com/UNI-T-Multimeter-Transmission-Capacitance-Temperature/dp/B0CDRX6DF3/ref=sr_1_1?crid=1MLCVCY69GQNX&keywords=ut60eu&qid=1699673515&sprefix=ut60eu%2Caps%2C461&sr=8-1&th=1

[NoMoreMagicSmoke]

I think a hardware store meter shootout would be interesting. Perhaps a Southwire, Ideal, Klein, etc. shootout. Maybe even throw in a higher end Harbor Freight meter as well. At the end of the day, are any of those meters even remotely decent or are they all the same quality as the AliExpress specials?

[joeqsmith]

I ordered some of your suggested low cost meters.  I think we all know the grill starter will damage all the UNI-T products and I doubt any of us are expecting any of the others to survive the low voltage generator.   So, to mix things up a bit, I bought what I consider should make a decent meter for electronics work.   Will it replace my Brymen BM869s....  Stay tuned.

[joeqsmith]

Klein Tools
If there is something at this price point in the US.

The Klein MM400 is under $60.  From teardown videos it appears to have a single-PTC MOV-less design and a CAT III/600V rating, which seems suspect.  However, it also appears to have a more limited function set, so perhaps they are able to pull off a "withstand without clamping HV" design.  It does have a pretty decent looking set of input resistors, but not the single large ~1k surge resistor.

The low cost meters have started to arrive.  Note how that Klein MM400 shares the current input.      I give the big thumbs down and it's not even out of the wrapper.   If the fuse is in series with the shared functions, my plan is to pull it and replace it with a short.  I have no desire to replace a fuse after every transient.   

The others are fine so far.

[GuidoK]

So, to mix things up a bit, I bought what I consider should make a decent meter for electronics work.   Will it replace my Brymen BM869s....  Stay tuned.

I can't wait to see which one it is.

I'd be really curious to the Metrix MTX 3293B or it's Chauvin Arnoux equivalent, that sadly didn't make win the poll from the keysight a while back.

All the cheap kaiweets etc stuff.... I really don't care about that. I don't see any significant useful progression made in that segment.

[joeqsmith]

... I really don't care about that. ...

Others do. 

[GuidoK]

Others do.

Yes I understand. But in the light of the robustness testing that you do, do you expect any surprises of the ~sub$50 kaiweets/zotek/aneng multimeters that flood the market and sponsored youtube channels in that regard?
That one of them stands out and has a robustly designed front end that will perform well in your test?
Obviously the only real way to find out is to test them, but my expectations are pretty low regarding that aspect.
The functional tests that you do with odd voltages (like detecting ac waveforms with a dc bias etc) might be the most interesting part for those cheap meters.

Some time ago I suggested the amazon commercial 90DM610 which was a rebranded Cem DT-9562 that at that time retailed at $49 on amazon that looks like it may have a pretty decent robust front end inside, but afaik that meter is not available anymore (certainly not at that price at least)

[joeqsmith]

Others do.

Yes I understand. But in the light of the robustness testing that you do, do you expect any surprises of the ~sub$50 kaiweets/zotek/aneng multimeters that flood the market and sponsored youtube channels in that regard?
That one of them stands out and has a robustly designed front end that will perform well in your test?

I am not expecting any surprises.  Based on previous experience, they will all work out of the box measuring components from my component test box accurately.   UNI-T meters will be damaged from a low ESD event.  One may fail with the low voltage 60Hz.  The others will not survive the low voltage generator.  None will be repairable. 

A few viewers will complain how the tests are unrealistic.  How it says right on the meter 600V max.  How we can't draw any conclusions from a sample size of one.  How dare I take a perfectly good meter and damage it.  How I am biased.  How they had this meter for 20 years and it has never had any problems. 

Obviously the only real way to find out is to test them, but my expectations are pretty low regarding that aspect.

Agree, this is why we test them and I suspect most have very low expectations. 

The functional tests that you do with odd voltages (like detecting ac waveforms with a dc bias etc) might be the most interesting part for those cheap meters.
Some time ago I suggested the amazon commercial 90DM610 which was a rebranded Cem DT-9562 that at that time retailed at $49 on amazon that looks like it may have a pretty decent robust front end inside, but afaik that meter is not available anymore (certainly not at that price at least)

As far as testing, I have not yet decided what all I will do with them.   It may depend on the meter.   

I've looked at a few CEM products.  Anytime someone talks about what they "look like" inside, I am reminded of that UNI-T UT181A of that last Keysight U1282A.  Both very expensive.  Both damaged from next to nothing.  At least I could repair the UNI-T (very rare)  where the Keysight is worthless.   I did offer to buy the Keysight meter Dave used for his video for parts in hopes to revive it but wasn't able to strike a deal.   

[rsjsouza]

A few viewers will complain how the tests are unrealistic.  How it says right on the meter 600V max.  How we can't draw any conclusions from a sample size of one.  How dare I take a perfectly good meter and damage it.  How I am biased.  How they had this meter for 20 years and it has never had any problems. 

There is another category: "I used this meter in my three phase distribution panel and not only it read 380V but I am still alive to tell the story".

The low key meters have their place and they will be stretched by their users far beyond any "safe" margin. Heck, even I did measurements with my dad's ICE 680R that would be considered child endangerment nowadays.

That doesn't detract in anyway the value of putting them to the paces. Besides, if they explode, people will tune in for the pyrotechnics. 😜

[joeqsmith]

T

There is another category: "I used this meter in my three phase distribution panel and not only it read 380V but I am still alive to tell the story".

True.
****
The comments from hackaday when I first started running these tests is priceless.

https://hackaday.com/2015/07/04/exploding-multimeter-battle-royale/
****

Well, I ran the first meter today and am going to have to eat my words.  Results were not at all what I was expecting.  There wasn't even a hint of drama.

[joeqsmith]

Most electrically robust UNI-T product I have looked at to date, outside of the ones I modified... 

 

[GuidoK]

Nice video. That was indeed an unexpected outcome, since EN61326 wasn't mentioned in the manual.
Let's hope all future Uni-T's meters handle the grill starter with no problems.
And it shows that a reasonable robust meter doesn't have to be expensive, although this is of course a pretty simple and limited multimeter.

[joeqsmith]

Nice video. That was indeed an unexpected outcome, since EN61326 wasn't mentioned in the manual.
Let's hope all future Uni-T's meters handle the grill starter with no problems.
And it shows that a reasonable robust meter doesn't have to be expensive, although this is of course a pretty simple and limited multimeter.

The Y1 transistors they selected are a bit more stout than what I normally see for a clamp and they took some abuse.  Had they used a second PTC, or better, just added the proven surge rated resistor, I am guessing the meter would have gone a lot further.   Then again, had the PTCs broke down the meter would have been in the recycle bin.  Good to see them using better parts even in such a cheap meter.    That shared current/fuse/spark gap IMO was a poor choice. 

Keep in mind when I first started to look at how robust these meters are, the meter that was the runner up survived 5kV.  It could also be repaired.  I tested it a second time on the new transient generator and it once again survived 5kV.   That meter was also under $50 and had a lot more features.   

https://www.aliexpress.com/i/3256803936810470.html?gatewayAdapt=4itemAdapt

[GuidoK]

Keep in mind when I first started to look at how robust these meters are, the meter that was the runner up survived 5kV.  It could also be repaired.  I tested it a second time on the new transient generator and it once again survived 5kV.   That meter was also under $50 and had a lot more features.   

Do you mean the Amprobe AM-510?
Because that retails (here in europe at least) currently for almost €100, whereas that uni-T is roughly 5 times as cheap (€19).
(these prices are including ~21% VAT)

[joeqsmith]

Yes.  It looks like Amprobe discontinued it.   

[rsjsouza]

The Y1 transistors they selected are a bit more stout than what I normally see for a clamp and they took some abuse. 

(...)

https://www.aliexpress.com/i/3256803936810470.html?gatewayAdapt=4itemAdapt

Thanks for sharing the link and P/N. I have some meters here that need their clamps changed and I keep forgetting to look at your older videos to get the P/N.

The SS8050 is also available at Mouser:
https://www.mouser.com/ProductDetail/Comchip-Technology/SS8050-HF?qs=T%252BzbugeAwjjubHjgf%252BCy6w%3D%3D

[GuidoK]

Regarding the cheap multimeter robustness testing, this might be an interesting specimen.
Fnirsi DMT-99
https://www.aliexpress.com/item/1005006225669621.html

Not that I expect it to be very robust, being a cheap (chinese) meter, but it's not from a typical DMM manufacturer (so who knows....) and it has an interesting feature that it can do some graphical logging. (quite unique in this price range)

It's one of those automatic style meters though, so I expect it to be a nuisance to use 
It's quite a new model, so there's not that much info on it out there (1 or 2 youtube reviews though).
But.... I haven't seen any CAT rating on the meter (in the youtube reviews) or in the manual, nor any compliance to an EN standard, so that might be interesting 
I think that would make it illegal to sell here in the EU at least (I think compliance to EN61010 for devices that can be connected to mains, including multimeters, in the EU is mandatory) 

Best wishes for the New Year 

[joeqsmith]

After talking with Fluke early on, I had initially hoped that meters with a higher CAT rating would be more robust.  I suspect if every company took the same stance as to what constitutes a pass/failure, that would be true.  But, as we have seen in many instances this has not been the case.    The only correlation I seem to notice when comparing the IEC standards how robust the products are is if they pass the EMC standards.   

[joeqsmith]

Transient Testing the UNI-T UT33A+ 2000 count DMM.

[joeqsmith]

Transient Testing the KAIWEETS KM401 4000 count DMM

[Veteran68]

Transient Testing the KAIWEETS KM401 4000 count DMM

I have the KM401. Based on what I've seen and heard, Kaiweets puts out some pretty decent meters in their price range. I also have their KM601S rechargeable "smart" meter. Their HT118A (6K count) and HT118E (20K count) meters gets rave reviews as well (Habotest sells the same models, not sure who the OEM is). Very similar if not the same as the Zoyi ZT-225 (25K count) meter I have. Speaking of the ZT-225, if you're looking for more cheap meter candidates to review/blow up, I'd like to see it tested.

What can I say, I collect (my wife would say "hoard") cheap and not-so-cheap meters. I think I'm up to just over 40 in the collection now.

[bdunham7]

Transient Testing the KAIWEETS KM401 4000 count DMM

Only use genuine Kaiweets!

I know it isn't what you are testing, but wasn't that meter actually fairly inaccurate during some of your basic checks?  And what is with the TRMS not reading your half-wave source?  I noticed on the teardown that there isn't an AC coupling capacitor as far as I can see and the voltage divider must be done with those MELFs. 

[bdunham7]

(my wife would say "hoard")

She's right....

[joeqsmith]

.... wasn't that meter actually fairly inaccurate during some of your basic checks? 

I never looked at what they spec but was surprised to see everything reading low.  Wasn't expected.   

And what is with the TRMS not reading your half-wave source? 

This particular meter doesn't offer manual range or I would have switched it.