Hi there,
I'm repairing this device for marcaurell.
I don't have so much time this weekend, so very quickly:
Measured between TP29 (non-inverting input of U9 before R31) and signal ground, DCV, auto-range.
Shorted input: 1,18V
Open input: 1,18V
300mVDC to input: 1,19V
It should be 1V at shorted or open input and 1,3V at 300mVDC at input.
It comes from RIC2, because this voltage is present also if I remove R31 or U14 and U9.
I checked Z6 (feedback resistors at COMP. AMP and feedback resistor at summary amp) - OK.
Can someone measure for me input to the comparation amplifier? Pin 1 of Z6 between signal ground (COM input)? I'm very suspicious that there will be problem, because comp. amp is working and it comes from RIC2 (it's a pity that I don't know what and where drives the switches inside RIC2).
Thank you very much!
Greetings from Slovakia.