One pop bumper behaves in attract mode but locks on in game or test, and can be fired from its skirt switch in attract mode.

F-14 Tomcat pop bumper locks on once a game starts

Cause: A solder splash shorting pins 5 and 6 of the 7402 at U50, the logic chip driving that coil.

Checks

• Grounding the tab of its TIP122 (Q69) in attract mode should fire and release the coil normally.
• Inspect U50 for solder bridges.

Fix

• Remove the solder bridge.

Systems

• Williams System 11A

Games

• F-14 Tomcat

Related tips

• F-14 Tomcat: left credit-display character scrambled
• Spinner works in switch test but scores nothing in play: factory reset
• Random slam tilts: replace the SRC6 resistor pack on the CPU board
• Diverter coils dead and flippers live at game over: 7402 at U50
• Occasional U10 PIA error at power-on, but the game plays
• Pinbot: Williams' U22 sound ROM download was wrong
• Pop bumper or slingshot machine-guns or locks on (Fire! and earlier)
• A row or column of lamps stuck on and very bright

Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Three, Clay Harrell