How the System 11 flash lamp circuit works
R1 (330 ohm) is a permanent path to ground that keeps the bulb faintly warm; when the driver fires, it grounds the bulb through R2 (about 5 ohm), which flashes it brightly. The pre-warm lets the bulb flash hard without burning out quickly. R2 (5, 7 or 11 ohm, 5 or 10 W) lets a 12 V #89 bulb run on the 25 V solenoid supply.
Systems
Related tips
- #89 flasher very bright or keeps burning out: it is a 50 V circuit
- Where the flash lamp resistors are by era
- Flash lamps stay lit after fitting LED flashers: System 11 warming resistors
- C-bank coil or flasher not working
- System 11 coil outputs
- How the System 11 A/C bank select works
- Early System 11 games have no A/C banks
- 50 V coils on earlier System 11 games
Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Two, Clay Harrell (pinrepair.com)