What was found
DURING MAINTENANCE OPERATION, POSITIVE TERMINAL ON TRANSFORMER RECTIFIER WAS GLOWING RED WHEN INSTALLED WITH POWER APPLIED. THIS WAS FOUND DURING A ROUTINE INSPECTION. THERE WAS NO INDICATION THAT THE AIRCRAFT WIRING HAD AN EFFECT ON THIS MALFUNCTION. THE AC CIRCUIT BREAKER DID NOT TRIP. POSITIVE TERMINAL LUG ON RECTIFIER WAS VERY DISCOLORED. THE PLASTIC INSULATOR WAS ALSO DISCOLORED AND MELTED DUE TO EXTREME HEAT. POSSIBLE DIRECT SHORT TO GROUND CAUSING MALFUNCTION. ATTACHMENT LUG LEADING INSIDE BOX NOTICED TO BE REPOSITIONED. RECOMMEND THAT A FAIL SAFE CIRCUIT PROTECTOR BE INSTALLED ON BOX.