Just picked up an '81 Fireball II and everything works great except some of the sounds. Voice call outs are fine as are pop bumper and slingshot sounds but no rollover or standup/drop target sounds and no background sound -- if I lean under the machine and listen really closely when these features are hit I can hear a very faint sound as well as the background sound. When I toggle sound option to old school "chimes" every switch appears to make a sound, it's only in 'modern sounds' modes where the problem appears. Thanks!

I did twist it back and forth a few times but will try the alcohol method. Would a dirty pot hold back some of the sounds while letting others through clearly?

Update: I got a deluxe cap kit from Big Daddy and recapped the board and everything works correctly now! I didn’t replace the 2 pots as that did not appear to be the problem. Thanks everyone for your tips and comments!!

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