The sound board works alone but fails, or speech is missing, once the speech board is connected.
Speech board faults
Cause: Speech EPROMs (2532s often fail), mixer chip IC2, or IC1. With sound but no speech the mixer IC2 is probably fine; with no sound at all, IC2 has almost certainly failed. IC3 is the speech amplifier and is well protected, so replace it last.
Checks
- With power off remove W1 and reconnect the speech board, then press the test switch.
Fix
- Replace the EPROMs or the chip found faulty.
Systems
Related tips
- Garbled or partial sounds from bad ROMs or sockets
- Missing words or sounds from cracked connector pins
- Setting up a sound board for speech
- Speech cuts in and out when the ribbon cable is moved
- System 6/7 sound and speech board ROMs
- Sound board jumpers for sound-and-speech games (2K ROM)
- System 9 sound and speech boards fit System 6/7
- Sound effects work but speech is missing or very quiet: replace the speech board op amps
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)