What the WPC custom chip does

The WPC ASIC on the CPU board acts as the address decoder and handles I/O addressing, the system clocks, the watchdog reset, blanking and the real-time clock. It replaced the separate logic chips and 6821 PIAs used on System 11.

Systems

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

Related tips

• What is on the WPC CPU board
• What fails on a WPC CPU board
• Running a WPC CPU board on the bench
• Dead CPU: the order to replace chips
• WPC CPU board versions and where they fit
• WPC-S and WPC-95 security PIC (G10) is game specific
• Bench-check the WPC CPU switch matrix circuit
• WPC-S and WPC-95 CPU boards need the matching security PIC

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