Two controlled insert lamps that share a wire colour stopped lighting. Replacing their diodes changed nothing.
Two inserts on the same wire never light: blown lamp driver transistor
Cause: The lamp driver transistor on the board for that line had failed.
Checks
- Check the bulbs and sockets with a known good bulb and diode.
- With the connector off, run a test lamp from the board pin for that line; if other pins light the test lamp and this one doesn't, the fault is on the board.
Fix
- Replace the failed driver transistor on the board.
Systems
Games
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Source: Pinball Repair help group!! (Facebook group)