Hello.
Got this bench some time ago, working fine (just 7905 was busted but quickly replaced and everything is fine).
But recently I started to note the following - resistance measurement is giving increasingly wrong (lower) results.
Say if for 20K resistor on 20K range it says 19.15K (when resistor is exactly 20K, 0.01% tolerance), for same resistor on 200K range it will say 13.35K, and around 10K at 2M range.
And these are going more and more inaccurate, as time goes by.
Also, if I touch any of contacts during resistance measurements, results will become wildly different - like for that 20K resistor, it will say 68K and so on.
So what might be causing this? I haven't done calibration according to manual yet, but I just want to get prepared, to know with what to start.
Volts and amperes measurement are ok, no issues so far.
Any ideas?