thanks everyone, I really appreciate it. I will be trying various things tonight. I already went through the giant list of secret functions (lower function + D for diagnostics, etc) and turned all the voices off and back on, etc... didn't find the master tune reset so I will look around for that.

but I have one question:
if I do the factory calibrations that erase the memory (if memory serves, the command for this is lower function > D > 12 > STOP) will I lose the presets or will the voices be RESTORED to factory presets? I don't know how to back up memory to cassette... have a Prophet 600 too that uses a similar system but I've never used it so I wouldn't want to backtrack...