Millionaire was the first Williams game with opto switches

Opto switches appear from Millionaire on, mostly U-shaped optos sensing drop target positions. Vibration from the targets can crack them off their boards.

Systems

• Williams System 11A

Games

• Millionaire

Related tips

• Opto switches dead all at once
• Keep opto switches clear
• Use a flashlight to test an opto receiver
• Opto receiver and transmitter voltages
• Fitting replacement optos the right way round

Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Three, Clay Harrell