Pots and switch acting up after year of storage.

[rdatman]

Hi. Just finished two j99 and two Millennia boards to complement the 4 T15s I built some years ago.

I couldn't get the T15s to turn on at all initially. There seems to be an issue with two where the gain switch mutes the signal above 75% (on switch-- maybe after 8-9 on detent) on two and some boards drop off and re emerge when I adjust resistance on the pots. The blue pots seem to be acting up.

The boards had OPA 627s in two or three, can't remember, but they seem to be socketed if I recall. Wondering if the issue is related to cleaning the pots or whether the legs of the op amps might be non conductive from slight corrosion.

Any feedback would be beneficial. They worked flawlessly when I put the rack down, and it was left in a good environment, not high in humidity or temperature extremes.

[tpryan]

It sounds like a typical cold solder joint problem. They oxidize over time and stop conducting. Try re-flowing all the joints on the board and see what happens.