A pop bumper or slingshot stays energized, or never fires.

Pop bumper or slingshot locked on or dead

Cause: Locked on: its playfield switch is stuck closed. Dead: fuse, coil, or the relay contacts in its supply.

Checks

• Locked on: check the activating switch.
• Dead: start a game and measure at both coil lugs; one lug only means a bad coil.
• No voltage at either: check the solenoid fuse, the T relay normally closed contact and the Q relay normally open contact.

Fix

• Adjust or replace the switch, coil, fuse or relay contacts.

Systems

• Gottlieb System 1

Related tips

• Flippers, slingshots and pop bumpers are not CPU driven
• Hold the Q relay in to test flippers and bumpers
• Backbox or playfield GI always off
• A CPU controlled coil does not fire
• What the Game Over (Q) and Tilt (T) relays do
• What happens when the T relay pulls in
• None of the CPU controlled lamps light
• How the Tilt and Game Over lamps are switched

Source: Gottlieb System 1 Pinball Repair from 1977 to 1980, Clay Harrell (pinrepair.com)