What was found
PARTIAL FAILURE OF POWER SUPPLY. EXPERIENCED A BACKLIGHTING FAILURE OF THE COMM RADIOS, ENGINE CONTROL PLATE AND TFO PANEL. USING THE WIRING DIAGRAM , 33-10-00-001, PAGE 1002, I TRACED THE FAILURE TO PIN 12 OF THE NORMAL LIGHTING POWER SUPPLY (148L). ALTHOUGH THE COMPASS AND INSTRUMENT PANEL PLATE ARE ALSO PART OF THE NORMAL LIGHTING POWER SUPPLY, THAT SECTION OF THE POWER SUPPLY WAS WORKING NORMALLY, IT WAS ONLY PIN 12 (28V/P5) THAT HAD FAILED.