Identifying a System 3 to 7 CPU board
System 3 to 6A CPU boards print the system after a dash in the board number in a corner of the artwork (-3, -4, -6, -6A). System 7 boards do not, but are easy to spot by the second 40-pin 6821 PIA and the single 7-segment LED; their number is 5764-09465-X4.
Systems
Related tips
- What changed on the System 6A CPU board
- System 6 CPU board test points
- System 7 CPU board test points
- System 6 CPU board jumpers J1 to J6
- A System 7 CPU board can run any System 3 to 7 game
- Run a System 6/7 CPU board on +5 V only
- Which CPU boards can run which system firmware
- System 7 CPU ROM sockets
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part One, Clay Harrell (pinrepair.com)