Parts of the 28 V solenoid supply
A backbox-mounted 35 A 400 V bridge rectifier feeds the power supply board, which has a 47 V varistor (MOV) across the supply and a 100 MFD filter capacitor. If the supply ever rises above 47 V the varistor shorts and blows the solenoid fuse.
Systems
Related tips
- High-voltage supply rebuild parts, System 3 to 11C
- What the power supply board takes in and puts out
- Test the power supply with its outputs unplugged
- Swapping power supply boards between generations
- No +5 V on a System 3-6 power supply
- No +5 V on a System 7 power supply
- Early Black Knights use the System 6 power supply
- Display supply low (under 90 V) after the resistors are changed
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)