thanks a lot kleinstein, you give me new hope,
i allready plan to open it, and run the test while open, and then knock on the relays while looking at the curves,
i do think it is very random, and i feel it is getting worse, not better,
i can also solder a wire from the ADC input, and from the REF and perform parallel measurements
to reveal where this odd jump come in, if i cant reveal it on ADC input or REF, it can only be the ADC chip i need to replace
since it contain all the gain stuff too, i think i give it a high value of possibility, even before i have performed any measurements,
wrong assumption ??
hey : we can even play a game : who can guess where it is, before we start to dig :-)
lets see who is the lucky ? or the most clever ?