The six coils run through the solenoid expander board fire two at a time in coil test, and drop targets, the saucer and the outhole kicker misbehave.
Expander-driven coils fire in pairs: drop target coil fitted without its second diode
Cause: The individual drop target reset coils in the 7-target bank had been replaced with ordinary two-lug coils with a single diode. On the expander circuit these coils need a three-lug version carrying a second diode, which stops current feeding back through the other branch.
Checks
- Look at every coil on the expander circuit: each should have three lugs and two diodes.
- Compare against the schematic, which shows two diodes on each of those coils.
Fix
- Fit the correct three-lug coils, or add the missing second diode to the existing coils, using the spare middle lug hole to make a new lug.
Systems
Games
Related tips
- Drop target falls instead of the ball being kicked out (SEB games)
- Drop target coils misfire after LEDs or a new lamp driver: expander boards need bulbs
- Solenoid expander relay buzzes or does not switch
- How the solenoid expander board doubles up coils
- Test the coils behind the solenoid expander
- Expander games: check the controlled-lamp power first
- Expander game ejects or drops targets at the wrong time
- Centaur uses its solenoid expander for the ball-to-playfield kicker
Source: Pinball Repair help group!! (Facebook group)