DMM cemetery .. #1 Appa 106 , Cyrustek cyrustek es51962

[Giorg]

I've received this little fella but V range shows OL all the time. Diode and temperature are not working properly.



I've checked all the input components, sparks gaps are open, PTC are around 1.5k and resistors are fine.

I was not able to find a proper schematic. I've learned that this is a common design in other rebranded meter.

I've lifted pin 35 VR1 "measurement input" and it's at around 1.2V all the time. So I reckon the IC is fried and needs to be replaced, but I cannot find any for sale. It's a Cyrustek ES51962 http://www.cyrustek.com.tw/spec/ES51962.pdf

has anyone found a source for this old IC? Another option will be to salvage the part from like a unit T70B, but I was not able to find a broken one for spares!

[Mkdsime]

maybe try simple thing as cleaning the contacts ?

[coromonadalix]

I dont think you'll be able to order it alone ??

The same chipset is used in Uni-T UT70B or in the  xtech EX730 clamp-meters

[mzacharias]

Take another digital multimeter and measure the input resistance (impedance) at the volt-ohms jacks in DC volts mode.

10-11 Meg-Ohms is typical.