One drop target lamp stays dark after the lamp driver connectors were repinned, the SCR was replaced and a known good bulb was fitted; there is almost no voltage at the socket in lamp test.
One drop target lamp won't light after board work: broken wire in the harness
Cause: The lamp's wire was broken somewhere in the harness between the switch area and the board.
Checks
- In lamp test, ground the lamp's drive wire right at the socket: if it lights, the socket is good.
- Then ground it at the board connector with a short piece of solid wire pushed into the housing: if it lights, the fault is on the driver board; if not, the wire is broken in the harness.
- Continuity checks can pass through a nearly broken wire, so trust the grounding test.
Fix
- Replace the broken wire from the socket back to the board connector.
Systems
Games
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Source: Pinball Repair help group!! (Facebook group)