It may have taken me until 1:30am, but I got it back to playable, and no worse off than when I started this mess. These games are making me old, I think I have another white hair now...
I think it was corrupted settings Ram in the end. While I was in there I upgraded speaker grounds, and added a ground to the main board stack. I also metered the power at the board stack ROM sockets and got it up to 5.01V Took some doing to adjust out the pots, but I got that too.
The chopper sounds are still faint, but at this point, I don't care. They're all present at least. I'm considering myself lucky. This is an MCRIII game after all
Found I had dumped the equavalent of $84.50 into it before I had to clear the settings, it'll be awhile until I'm up to what I've paid for it, but not bad. What is that, side art and a power brick cap?
It's a terrible feeling when one's grail goes down. It's getting harder to get mileage out of 30 year old comptuers, but I'm tryin' Excuse the pun, off to bed.