System 7 CPU jumpers that are the same on every game
Apart from the eight jumpers that differ between Hyperball/Defender/Star Light and the other games (3, 5, 6, 10, 24, 26, 27, 28), every System 7 CPU board has: in W11, W14, W17, W19, W20 and W22; out W4, W9, W12, W13, W15, W16, W18, W21 and W23. W7 and W8 (IC7 inverter bypass from PIA IC18), W25 (sound PIA IC36) and W29/W30 (IRQ from PIA IC36) are not set by the table. Use this to spot a board someone has re-jumpered.
Systems
Related tips
- Identifying a System 3 to 7 CPU board
- System 7 CPU board test points
- 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
- System 7 CPU jumpers differ for Hyperball, Defender and Star Light
- Obsolete chips on System 3 to 7 CPU boards
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Two, Clay Harrell (pinrepair.com)