Which CPU boards can run which system firmware
A System 3 board can be modified to run System 3, 4 and most System 6 code (not Firepower). System 4 boards run System 3, 4 and most System 6 code, and System 6 boards run System 3 to 6 code; none of these run System 7 code. A System 7 board runs anything from System 3 to 7 when its ROM jumpers are set and the EPROMs are formatted to match.
Systems
Related tips
- A System 7 CPU board can run any System 3 to 7 game
- Run a System 6/7 CPU board on +5 V only
- Run the System 3-6 built-in CPU test (SW1)
- Identifying a System 3 to 7 CPU board
- System 6 CPU board test points
- System 7 CPU board test points
- System 6 CPU board jumpers J1 to J6
- Chips a System 7 CPU board needs to run the Williams test ROM
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part One, Clay Harrell (pinrepair.com)