Switch care by type

Microswitches need no cleaning; adjust them only by loosening the two screws and rotating the switch, never by bending the actuator, and do not overtighten. Leaf switches: pull a business card through the closed contacts, never file the gold-plated contacts, then reset the gap. Optos: clean both the emitter and receiver with a cotton swab dampened with glass cleaner.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

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