A look at the Uni-T UT210E

[kkontak]

Just found out this hack and tried on my UT210E. Worked great!

Two observations:

1. By adding a 2nd feature (AC mV) in NCV mode, using the below 2-byte hack, you also add a 3rd feature (AC A 6000A) which seems silly to me. The $1D byte is really useful for the mV feature to work? Because all it does, is to enable the 3rd feature.

NCV, NCV mV
---------
9C: 00 02
AC: 00 1D

2. When I opened my unit, I noticed a QC fail. The R37 resistor was soldered only in one of the pads. Still worked tho, even after years of beatings around in the toolbag on many work fieldtrips.

[ceut]

Time has passed since my contribution here...2017   
A quick follow up of a problem of one of my 2 UT210E (the one I have given to my brother).
I have to fix his FAAC D600 motherboard (from a motor garage door) which has failed and some burned part on it.

So, after having fixed it at home, I have gone to his home, and when I have rechecked the power voltage line, his UT210E reads 51V DC    (for a 24AC 86VA transfomer, which I have checked at home at 24.85V RMS on my Keysight U1233A and with my Siglent DSO 68V peak-peak (34V max and -34V min)).

=>So big fail for this 6 years UT210e old that I have flashed and contributed for mod it here  https://www.eevblog.com/forum/testgear/a-look-at-the-uni-t-ut210e/msg1316832/#msg1316832

I have worked on it for about 3 hours, reflashing other 24C02 calibration file, checking many parts etc..
All other functions worked well.
Then I have removed fully the motherboard, and found the issue 
==> Wear of the rotary switch !   
2 traces have lost their solder mask  as you will see on the photos.
I have put a piece af tape, and it is working again, with the good calibration I have made 6 years ago 
Now I have to find how I can isolate this traces... will try some UV solder mask

[kloetpatra]

I mainly use mine in 2A mode (once a week). A while ago I noticed incorrect Amp readings or mode changes (beep) without touching. Firmly pressing the selector wheel the issue goes away. So I think it's a bad contact in my case.

Just checked the inside and I can see there's way much more grease. Maybe you should add some grease too?
While the traces still show no signs of wear there's a little bit of green residue on one of the copper spring contacts.

[ceut]

I mainly use mine in 2A mode (once a week). A while ago I noticed incorrect Amp readings or mode changes (beep) without touching. Firmly pressing the selector wheel the issue goes away. So I think it's a bad contact in my case.

Just checked the inside and I can see there's way much more grease. Maybe you should add some grease too?
While the traces still show no signs of wear there's a little bit of green residue on one of the copper spring contacts.

wow 
This grease was put originally from factory ? Is it a recent batch ?

On my 2 UT210e from 2017: no grease at all inside.

I have fixed the 2 mine which were having the exactly same wear problem on the same place/traces.
=>Fixed with UV solder mask, then a very little WD40 on the rotary switch+trace - hope it will last with that.

[kloetpatra]

This grease was put originally from factory ? Is it a recent batch ?

Yes, I didn't add anything. I think it's from 2015. Nice fix, I hope it'll last long. I'd rather recommend silicone based grease. WD40 technically is not a lubricant. Moreover it is hydrocarbon based. Amorphous plastics and hydrocarbons don’t play well together. Hydrocarbons attack the chemical structure of amorphous plastics and break them down. It would be safe for crystalline plastics.

amorphous: PC, Styrene (including ABS), PVC
crystalline: PP, PET, PE (all types), Nylon