Quoted from bpa:Sometimes when I turn it on, I will have no sound. I'll start playing and eventually I will get sound effects while playing. Once that happens and then the ball drains, I will get music back. I reseated all of the connectors on the sound board but that did not fix the problem.
Sounds like you might have capacitors dying in the sound area. If the sound effects fade in rather than coming in instantly, I'm expecting the caps are just bad enough that they start acting correctly once they've "warmed up".
If it's a sudden return, there might be a transistor or diode for the sound that's flaky.