Glue new-style optos down

The later U-shaped optos used with LM339 boards break their leads and fall off easily. Put a small dab of silicone under each opto when fitting it.

Systems

• Williams System 11B
• Williams System 11C

Related tips

• Use a flashlight to test an opto receiver
• Drop target not sensed when down
• Fitting replacement optos the right way round
• Opto switches dead all at once

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