Originally Posted by
jimkarl
OK. Well I just ordered some 1uf tantalums so maybe I didn't need them, but that will be a phase 2 attempt if the replacement c8 doesn't work. i don't want to change too many things at once. The board is partially out but connected by many wires, so I do have some access to the underside. Should be enough to unsolder and solder a new part in though.
Question - why is that 100pf such a high voltage rating? (like 600v or 630v I can't remember) There's no way that circuit is seeing that kind of voltage right? Can i use a lower value? and if so , what is the safest lowest value to use?
There are two ics only on this revision. They are marked S 430 3532 but the parts list calls it a AN 301 Op Amp. I'm not clear from the kenrockwell link, or comments here, if those should be replaced and if so, is it a direct drop in with no circuit modification (I don't want to change any circuit design). I guess one thing I could try is swapping those two to see if the problem moves channels too.