|Bird Dog||Re: Orange w/ Fender p.t.??|
I would first check the red/yellow for continuity with the two red leads. Then I would run a resistance test from each red to the red/yellow. If the readings are very close, you probably can count on the red/yellow being your center tap, in which case you will need to replace your bridge rectifier with a full-wave style, as used in most vintage Fenders. I encountered this when replacing the high voltage PT in a 135 watt twin with a vintage re-issue PT to bring the voltages down.