Quoted from PinballManiac40:So go to the blue and yellow at the lamp board connector and repin that single wire.
He means go to the lamp driver board, locate connector J1, go to pin 8 and verify if it is a Green with Yellow tracer wire. Then re-pin that position.
You can double check by making a continuity check from the lamp green/y wire to the lamp board connector.
As he says, colors may vary from the schematics.