Sound needs the A1P4 cable
Without the plug at CPU A1P4 the CPU cannot talk to the sound board, which then fails to boot and stays silent.
Systems
Related tips
- The A6 sound board
- Both sound board LEDs dark
- Constant beeping, display blank, GI on
- Logic chips worth stocking
- U11 must be a 74HC123AN
- Replace a failed 6116 RAM with a 6264
- CPU battery and socket parts
- CPU board 26285 versus 26285-1
Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)