Where the coil diodes are on System 11
Before Big Guns, each coil has its diode across its lugs, banded end on the power side. From Big Guns on, the diodes for all coils except the flippers are on the auxiliary power driver board, which keeps them away from vibration and heat and means a coil can be wired either way round. Flipper coils always keep their diodes.
Systems
Related tips
- Testing coil diodes on the auxiliary power driver board
- Later System 11 moved relay and diode boards to the backbox
- How the System 11 A/C bank select works
- How System 11 A/C switched solenoids work
- A-bank coil not working
- Whole A or C bank of coils dead
- C-bank coil or flasher not working
- Wrong coils fire together (A/C bank game)
Source: Repairing Williams System 11 Pinball 1986 to 1990, Deel 1, Clay Harrell (pinrepair.com)