Fitting replacement optos the right way round
An opto fitted backwards is likely ruined. On old-style boards the red side is the transmitter. On new-style optos the side with the white dot or notch is the receiver, and it lines up with a white dot on the board.
Systems
Related tips
- Glue new-style optos down
- Opto receiver and transmitter voltages
- Millionaire was the first Williams game with opto switches
- Opto switches dead all at once
- System 11B opto board fails with good optos
Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Three, Clay Harrell