My first instinct is jumpers on old Bally games when I hear this. Some of the games even had soldered in jumper wires for settings. So when a board switched games you had to grab the iron and change them. So rip out the manual and go over each board setting. After that I'd think corrupt ROM or bad chip.

The manual on page 7 shows a chart with sound options on switch 29 & switch 30 . Have you tried all combinations?

Also inaddition to above its always a good idea to recap the old Bally boards. Sound bounds cap kits are just a few bucks.

What are switches 29 and 30 on the CPU set for? These change the sounds on HG to the strange electronic chime sound and change the startup tune. I have them both set on.

Well that's interesting. My game plays different sounds when I shut those two off. Is there any chance you can upload a video so we can hear what sounds are playing?

If the dip switch never closes, try to rock the dip switch back and forth. A little bit of solvent can help clean it too.

dip switch banks are as difficult as IC to replace. I suppose you can jumper it on the back side of the PCB too.

the PROM was bad on Tom's sound board.

Andrew