Mounting WPC-style base plates

They fit the original footprint, but wiring may need rerouting, the plate may need a slight twist to clear harnesses and GI, and a GI lamp may need moving. Re-using old holes, fill them with a toothpick and white glue so the screws bite.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7

Related tips

• WPC-style conversion: plunger, springs, bats and coil
• Converting System 3-7 flippers to WPC-style mechanisms: main parts
• WPC flipper coils, weakest to strongest

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)