Quoted from ezed123:One other thing I noticed on the game is that when the middle pop bumper fires it also triggers the left pop bumper. They simultaneously fire together.
Make sure the switch on the pop bumper is properly adjusted and vibrations arn't triggering it. I'ts probably a good idea to replace the small caps soldered to the switch.
As for the sound, eliminating the board, rebuilding the connectors would be a good idea. Also clean and inspect the speaker. It may be worn out.