Recurring faults on the 8-driver board that did not go away after two weeks of recommended board work and modifications.
STTNG 8-driver board keeps misbehaving: the lower diverter coil was the cause
Cause: The lower diverter coil, although it measured close to its rated resistance.
Checks
- Note which coil fires when the fault appears and take that coil out of circuit to see whether the problem stops.
- Check the coil's diode and resistance, but don't rule the coil out just because the resistance is close.
Fix
- Replace the lower diverter coil.
Systems
Games
Related tips
- Why WPC coil diodes are on the driver board
- Measuring a coil after replacing its driver transistor
- STNG: diverter coils lock on during play
- Underplayfield diverter coil burns and locks on: shorted Q15 on the aux 8-driver board
- Driver transistor dies after fitting a coil that has a diode
Source: Pinball Repair help group!! (Facebook group)