I'm working on a Bally Black Belt where the background sound cuts out intermittently mid-game. It's weird, the background sounds will work fine, then cut out--but the sounds made by hitting targets etc still work. Then on the next ball, background sound is back...and eventually cuts out sooner or later. I replaced the 4 commonly-replaced electrolytic caps from a kit purchased from Marco. I reflowed the solder on the header pins and re-pinned the female connectors. Seemed to improve for a bit, but it's still doing it. Any ideas?
Edit: i also changed the potentiometer on the coin door and the pot VR1 on the sound board