GS4 questions

[Ferric Toes]

Standard Polyester capacitors are used and the small amount of charge retention should not matter. One thing I just remembered is the GS2 did not have auto-zero. You had to do it manually by the push button on the front panel. Later Goldscans did have auto -zero, as in the GS4. I also remember long ago modifying some GS2's to have auto-zero, but for those with the potted box, you can't access the necessary part of the circuit. The potted box was to prevent leakage drift in a high Z part of the circuit. This was later dispensed with as better pcb's were used.
Also, see my PM.

Eric.

[Paul Harris]

I'll have to order some polyester capacitors. After what you say about the GS2 using a manual press to zero, I don't think I'll dwell on this part of the circuit much longer, at least for the time being. Spoke with Bill too and he said he preferred manual. Thanks Eric