After the game was moved, the bonus lamps no longer advance or count down and stay stuck on one value (first 1000, later 2000). No fuses are blown and no loose wires can be seen.
Bonus lights stop advancing and stay on one value: stepper unit plunger sticking
Cause: The bonus stepper unit had stuck: one of its solenoid plungers was not moving freely, so the ratchet wheel no longer stepped.
Checks
- Find the bonus stepper unit and, with the power off, push each of its plungers by hand: one steps the wheel up, the other down, and both should move smoothly and spring back.
- Check the return springs and that the ratchet pawls engage the wheel.
Fix
- Free the stuck plunger: clean the plungers with isopropyl alcohol, replace worn coil sleeves, put a drop of light oil on the metal-to-metal pivots and shaft (not the plungers), and work the mechanism by hand until it moves easily.
EM games have line-voltage circuits: unplug the game before working on the stepper units.
Systems
Games
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Source: Pinball Repair help group!! (Facebook group)