The main solenoid fuse blows when a game is started.

Solenoid fuse blows at start on 1972+ Williams or 1976+ Bally EM

Cause: From 1972 Williams (and from 1976 Bally) ran the pop bumpers and slingshots on DC made by a silicon bridge rectifier and a filter capacitor. These bridges can short internally.

Checks

• Test the bridge rectifier with the meter's diode setting, or substitute a new one.
• If the fuse beside the bridge still blows with a good bridge, check every DC device (pops, kickers) for a shorted coil or wiring.

Fix

• Fit a new bridge rated 25 A and at least 100 V. A 50 V bridge will work in an emergency but has little margin.

Systems

• Electro-mechanical

Related tips

• Solenoid fuse blows when a pop bumper fires (1970s Williams/Bally)
• Bridge rectifier for 1970s Bally and Williams DC coils

Source: Repairing Electro-Mechanical (EM) Coin Operated Games to 1978, Part Two, Clay Harrell (pinrepair.com)