The heartbeat background sound keeps playing after the game ends; the sound board plays correctly when its input tabs are grounded by hand.
Background sound never stops at game over: sound-line driver chip
Cause: A failing 7408 on the driver board that feeds the transistors driving the sound select lines (four of the five), so one line stayed active.
Checks
- Measure each sound select line from the driver board; it should drop when inactive.
- Trace back from the sound-line TIP102s to their predrivers and the 7408.
Fix
- Replace the 7408; the five predriver transistors were renewed at the same time.
Systems
Games
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Source: Pinball Repair help group!! (Facebook group)