I have a UT136C which started playing up. The volts would not zero, and fluctuated around 130mV
![Bullshit Detector :bullshit:](https://www.eevblog.com/forum/Smileys/default/BullshitDetector.gif)
, and I couldn't trust the other ranges.
So I opened it up. THe opening of these things isn't really posted up properly nor is there much detail in the manual.
After removing the battery and two lower screws, the case halves separate around the seam in the red plastic mid-way between top and bottom.
Separate the case near the lead connectors first, then pull it apart hinging on the battery end, and disengage the two plastic lugs near the top.
Inside, I found a number of areas where flux had been left around some through-hole soldering. Especially the "SELECT" switch.
So I removed the flux with a screwdriver, then cleaned the board both sides with isopropyl, dried it off, and reassembled.
Make sure both side lugs are engaged above the PCB or else the switch won't operate correctly and you'll be opening it up again.
Good news - the meter started reading properly again. While I was at it I found some decent leads as the OEM ones are terrible and one probe had fallen off.
So - all back up and running. 0V reads 0.1mV. Also 0 ohms reads zero which is nice. And the continuity beeper is REALLY responsive.
Original purchase price was £11.86 so I suppose I can't grumble....