One controlled lamp never lights on a Bally game fitted with an Alltek replacement lamp driver board, and the bulb, socket and wiring are good.
Alltek lamp driver, one lamp dead: replace the bad SMD SCR with a 2N5064
Cause: The surface-mount SCR that drives that lamp has failed.
Checks
- Prove the bulb, socket, wiring and connector first.
- To test the SCR itself, apply about 5 V to its gate and see whether the lamp comes on; grounding the lamp's return only proves the wiring.
Fix
- Cut out the failed surface-mount SCR, then fit a through-hole 2N5064 SCR in the alternate footprint the board provides under each surface-mount part.
Systems
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Source: Pinball Repair help group!! (Facebook group)