Products > Test Equipment

UNI-T UT61E Multimeter teardown photos.

<< < (181/217) > >>

Kakalas:
Hello,

Maybe someone could help me to solve this problem...  :-//
I have a multimeter UT61E for some time, I use it a little, it's almost new. Recently I noticed that UT61E began to show a false VDC (when nothing is connected shows about -1.15 VDC). I tried to carry out calibration according to the guide (link below), but no result, since the margin of error is quite large and goes out of calibration range. Would anyone have any ideas how to fix it?

http://gushh.net/blog/ut61e-calibration/



retiredcaps:

--- Quote from: Kakalas on May 13, 2016, 11:06:32 am ---Recently I noticed that UT61E began to show a false VDC (when nothing is connected shows about -1.15 VDC).

--- End quote ---
Questions.

1) Have you tried a new battery?
2) If you short out the probes with the meter on DCV, does it show 0.0?
3) Post clear focused pictures of your meter so we can see the pcb (both sides) and look for any obvious damage.
4) Does ACV work?
5) Does resistance work if you measure a 1k ohm resistor?

MrSlack:
Mine did all sorts of weird stuff when the battery went flat. First point of call on these I think.

joeqsmith:
I am interested in knowing more about how people who have recommended changing the meter have validated their changes.

Just a little thought on this....   I ran both the 61D/E and they failed with a basic ESD pulse.    I also ran a UT181A that failed with a single ESD event.  The UT181A has PTC, MOVs and secondary clamps.       

On the flip side, I have ran a few meters that have survived not only ESD but some much higher energy transients that had no MOVs.   The last one I ran was the UT10A which not only survived the basic ESD but went on to survive a 3KV 100us FWHH with a 2 ohm source with the meter set in all modes. 

In the case of the UT181A, the cost of the meter (and my own interest) drove me to have a look at the design in more detail.   In this case the layout has a few problems that needed to be addressed.  A little Dremel, X-acto and dope.    And no, adding a clamp to the output of the regulator was not one of them.   

With the recommendation to add MOVs, I am curious what the goal is?  Safety, robustness?  I would like to know how this was validated?   Do we even know if there was ANY improvement?  Worse, did adding them make the meter less safe?      I can see someone getting a false sense of added safety.   

It could very well be that UNI-T actually tested the meter with and without the additional parts and had the same performance and decided to save some money.  I have no idea.   

hgg:
I have ordered two of these :

http://www.tme.eu/gb/details/siov-s20k625/tht-varistors/epcos/b72220s0621k101/

In what circumstances adding these MOVs will make the multimeter less safe?

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod