Two unrelated coils (the trough eject, solenoid 1, and the left slingshot, solenoid 9) do nothing in test, yet both fire when their driver transistors are grounded by hand.

Trough eject and left sling dead together: reseat the CPU to driver ribbon

Cause: Those coils are switched by the same data line coming from the CPU board over the ribbon cable (with solenoid 17 and flasher 25 on the same line). A poor contact on the ribbon drops all of them.

Checks

• Check whether solenoid 17 and flasher 25 are also dead in test; if so the shared data line is the suspect.
• Inspect the ribbon cable plugs between the CPU board and the power driver board.

Fix

• Power off and reseat both ends of the ribbon cables between the CPU and driver boards. That alone fixed this game.

Systems

• WPC-Security (WPC-S)

Games

• Theatre of Magic

Related tips

• Slingshot also fires an outlane magnet: ribbon cable not fully seated
• Backbox GI out while flashers work: burnt connectors at J120 and J121
• Kicker dead in coil test plus a lamp row and column out: reseat the CPU to driver ribbon
• Resets from worn power connectors between transformer, driver and CPU boards
• Reseat the ribbon cables before chasing odd behavior
• GI string dead with a scorched connector
• GI out because the GI connector burned
• GI connectors on the driver board

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