A click or buzz at the coin door each time the ball drains, or a solenoid fuse that blows with no playfield coil at fault.
Coin door clicks during play, or F4 blows from the lockout coil
Cause: The coin lockout coil is powered nearly all the time (early games drop it briefly at each drain, which is normal). Being on constantly, it can burn and short (page 16).
Checks
- If the solenoid fuse blows and every playfield coil checks good, test the lockout coil and its diode.
Fix
- A home game does not need the lockout: disable it by cutting the thinner wire on the lug at the unbanded end of the diode, and use free play or a low replay setting.
Systems
Related tips
- Game reboots during play from slam switch noise
- Saucer fires at power-on and blows the playfield fuse: wrong coil killed its transistor
- Centaur uses its solenoid expander for the ball-to-playfield kicker
- Drop target coil fuse keeps blowing: shorted diode on the coil
- Coil locks on at power-up and gets hot
- No playfield coils work
- Use the solenoid test to find a coil that does not fire
- How the solenoid expander board doubles up coils
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)