The sound board test button works, the driver board checks out, but there is no sound in play or in the solenoid test, and grounding 10J3 pins 2, 3, 4, 5, 7 gives nothing.
No sound in play or solenoid test, and grounding inputs does nothing
Cause: An input held low on the sound board, so the PIA thinks a sound is always being requested. Usually a failed 4050 buffer (IC8 or IC9); less often a pull-up resistor R37-R44 or a broken trace.
Checks
- Each of 10J3 pins 2-9 should read +5 V (supplied through R37-R44).
- PIA pins 10-17 should be high on a logic probe and pin 18 low.
- A low PIA input with pin 18 high confirms it.
Fix
- Replace the 4050 feeding the low input (in the reported case IC8, pins 4/5 low).
Systems
Related tips
- No sound effects in play though speech works: check the sound board PIA
- Sound self-test passes but some game sounds never play: bad PIA on the sound board
- Quick sound checks by grounding
- Sound board test button gives no sound: normal on Joust
- Sound test works but sounds missing in play
- Parts of some characters missing on alphanumeric displays
- Test the sound board inputs one at a time
- Sound CPU pin voltages with the EPROM removed
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)