Targets hang up instead of dropping.

Drop targets do not fall

Cause: Over-tightened screws holding the plastic rails to the metal body, or the wiper board to the rails, crush the rails so they drag on the targets.

Checks

• Check whether the target slides freely with the screws backed off.

Fix

• Loosen the screws, or fit a thin plastic shim to give the target room.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A

Related tips

• Testing a System 3-6 drop target bank
• System 3-6 drop targets use two switches per target
• Cleaning and rebuilding System 3-6 drop targets
• Drop target does not fall when hit
• Drop targets will not reset or stay up

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)