The top pop bumper did not work. After fitting a new coil the 1 A playfield fuse blows at power-up, before the drop targets even reset; with the coil unhooked everything else works.
Top pop bumper dead, new coil blows the 1 A playfield fuse at power-up: bad driver
Cause: The pop bumper's drive transistor had shorted, turning the coil on as soon as power was applied.
Checks
- Note when the fuse blows: at power-up with no switch closed points to a shorted driver.
- Check the coil diode orientation against a working pop bumper: the thicker power wire goes to the lug on the banded side of the diode.
Fix
- Replace the drive transistor for that pop bumper (and check the coil's diode and wiring before powering up again).
Systems
Games
Related tips
- No sound and not even a speaker hum: bad crimp on the sound board's 12 V feed
- Coil locks on at power-up and gets hot
- Check every coil's resistance before first power-up
- No playfield coils work
- Finding the coil that blows F4 (and stops the last flash)
- Finding a burned solenoid coil
Source: Pinball Repair help group!! (Facebook group)