If you are referring to the switch (S33) on the MPU, that's the "memory clear" button. It does not reset the board, unless it has a mod ?
Ahh...OK, yes it is S33, no mods there, that would explain why the sound settings reset.
I'd say you have corroded pins on the connector. If Ken has looked at the board, assume it is working - so I'd tackle the connector. If the ROM sockets have not been replaced (tedious and time consuming), then they too could be the problem.
OK, I'll work on the connector, it is an IDC type (shown below):
Is it better to replace this with a molex .100 type?
