Original-style U optos are now scarce

The original Williams U optos were made by Motorola, then by QT Optoelectronics (identical parts under a new name), which Fairchild later bought. Fairchild dropped the exact part. Newer similar optos have slightly different leg spacing and specs and may or may not work, so leftover QT stock is the safest replacement.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)

Related tips

• Opto styles used in WPC games
• Reusing an original U opto case with new internals
• Testing an opto receiver
• Opto parts to keep on hand
• Cleaning dusty optos
• Flipper cabinet opto switch boards
• Where WPC games use opto switches
• Opto wavelengths: 880 nm and 940 nm

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Three, Clay Harrell (pinrepair.com)