As soon as the game is switched on, the lock diverter coil pulls in and stays on, getting very hot.

Lock diverter locks on at power-up and gets hot: shorted driver transistor Q22

Cause: The diverter's drive transistor, Q22 on the CPU board, had shorted.

Checks

• Test Q22 for a short; the coil's diode (D8 on the auxiliary board here) should be checked too, since a bad diode can kill the transistor.

Fix

• Replace Q22 with a TIP102 and check or replace D8.

Systems

• Williams System 11C

Games

• Rollergames

Related tips

• CPU and driver board transistors by position
• Quick check of all TIP122/102 drivers before first power-on
• Use TIP102 when replacing a TIP122
• One or a few coils lock on at power-up
• 20-second test for shorted coil driver transistors
• A coil or flasher comes on and stays on at power-up
• STNG: diverter coils lock on during play
• STNG: under-playfield diverter coils lock on during play

Source: Pinball Repair help group!! (Facebook group)