What the auxiliary power driver board holds
From Big Guns on, the auxiliary power driver board carries the A/C bank select relay, the solenoid bridge rectifiers (+50 V and +25 V, formerly bolted in the backbox), up to eight TIP36c drivers for 50 V devices (only as many as the game uses are fitted), the coil diodes for all coils except flippers, and the 50 V solenoid fuses.
Systems
Related tips
- What the System 11 auxiliary power driver board does
- Auxiliary power driver board fuses
- Testing coil diodes on the auxiliary power driver board
- CPU and driver board transistors by position
- Testing driver transistors in diode mode (board out of game)
- When a driver fails, replace its pre-driver as well
- Coil stays on after the CPU-side driver parts were replaced
- One or both flippers weak
Source: Repairing Williams System 11 Pinball 1986 to 1990, Deel 1, Clay Harrell (pinrepair.com)