Not one controlled (insert) lamp works, though the 18 V lamp supply test point reads normal and a test lamp jumpered at the lamp connectors stays dark.
No insert lamps at all, lamp supply fine: broken trace under a driver board capacitor
Cause: A cracked circuit trace underneath one of the large filter capacitors on the power driver board.
Checks
- Check the CPU to driver board ribbon cable is fitted the right way round and fully seated.
- With the game in lamp test, press gently on each of the large capacitors on the driver board; if the lamps come on, the trace under that capacitor is broken.
Fix
- Bridge the broken trace with a jumper wire on the back of the board.
Systems
Games
Related tips
- How a WPC coil, flasher or lamp driver chain works
- 12 V unregulated LED out on the driver board: open track to C8
- Flasher glows full bright until the bulb blows: shorted driver transistor
- Testing a coil diode on the driver board
- Taking the power driver board out of the backbox
- 20-second test for shorted coil driver transistors
- Testing a 74LS374 driver latch with the diode setting
- Replace the pre-driver along with a failed driver transistor
Source: Pinball Repair help group!! (Facebook group)