I got two U1252 multimeter, one is U1252A, the other is U1252B. Their are almost identical and has the same feature as U1253A/B except it is LCD monitor while U1253A/B has a fanccy OLED, and BOTH of my two U1252 have problem with measuring DCV & Resistor when most of the other features are fine.
I record it to a video to demostrate what is like now, here are my observations:
1. with probes open, the resistor reading is not "OL", it's tens or hundreds Mega ohm. Measuring resistor more than 1M will notice obvious drift.
2. it's highly huminity sensistive, a few second's of hair-dryer blowing will make the reading to "OL", and everything seem more accurate than before, but it will slowly drift back to prior status.
3. DCV is similar, the reading drift and highly senstive to the hair-dryer.
4. DC mV is very accurate and not drifting. So I believe it about the attenuation/amplification?
5. There are 2 peice of PCB, and I tried apply the hair-dryer seperated, the buttom one is suspicion for the problem, it's much more sensitive to the hair-dryer.
6. I have two of these multimeters and BOTH of them have the same problem, so I think it's kind of common problem for this model, maybe there are people've run into and solved it, but there are not more useful result by Google "U1252A problem".
Thanks in advanced.