Sound effects are missing during play while speech still works. The sound board's own test button plays sounds, but the coin door sound test and grounding the sound input pins do nothing.
No sound effects in play though speech works: check the sound board PIA
Cause: The 6821 PIA that receives sound commands on the sound board had failed, and the socket for the board's processor was bad.
Checks
- With a logic probe, confirm the input buffers respond when each sound input pin is grounded and that the signals reach the 6821.
- Inspect the chip sockets on the sound board for loose or damaged contacts.
Fix
- Replace the 6821 PIA on the sound board, and replace any bad chip sockets (here the processor's socket).
Systems
Games
Related tips
- Damage after the black and white plugs were swapped
- Sound effects work but speech is missing or very quiet: replace the speech board op amps
- Setting up a sound board for speech
- Sound board jumpers for sound-and-speech games (2K ROM)
- No sound in play or solenoid test, and grounding inputs does nothing
- System 9: is the sound fault on the CPU board or the speech board?
- Segments missing or stuck on: CPU board PIAs 9B and 7B
- One PIA output does not toggle in the test EPROM test
Source: Pinball Repair help group!! (Facebook group)