Hiya! I recently bought a 1974 Bally Champ, and it all seems to work fine except for that some of the lights only seem to turn on in specific situations. The extra ball lights on opposite sides of the playfield are supposed to light when the bonus reaches 8,000, and then switch between each other every time the bonus is increased. Once the bonus hits 15,000, they both are meant to stay on until the ball drains. When the bonus reaches 8,000 they sometimes work, and they always work once the bonus hits 15,000. Also, the bonus lights only seem to turn on some of the time, and not consistently. I can't figure out if there's something dirty that needs to be cleaned or what. The bulbs all seem to work, but totally inconsistently.

Sweet! Thanks for the help! I'll try cleaning the disk next!