One rollover star button keeps scoring (points, sound and bonus) without being touched. Re-gapping the blades and slipping paper between the contacts makes no difference.
A rollover button keeps scoring on its own: leaky capacitor across the switch
Cause: The small capacitor soldered across the rollover switch had broken down and was leaking, so the switch read as closed. (The other part across the switch is the matrix diode, which must stay.)
Checks
- In switch test, see which switch number is stuck on.
- Under the playfield, tell the capacitor from the diode (the diode usually has a band) and look for burnt or damaged parts or leads touching the mounting bracket.
- Snip one leg of the capacitor: if the false scoring stops, it was the cause.
Fix
- Replace the capacitor (the game will run without it in the meantime, but very fast rolls over the button may be missed).
Systems
Games
Related tips
Source: Pinball Repair help group!! (Facebook group)