What was found
(CAN) CUSTOMER EXPERIENCED AN EXTERNAL POWER REJECT ON HIS ACFT. THE AC POWER TRIP OCCURRED IN THE HANGAR DURING THE UTILIZATION OF THE GENERATOR POWER. THE EXTERNAL AC AVAIL BLUE LIGHT IN THE COCKPIT WAS BLINKING FOR A SHORT TIME PERIOD WHEN GPU POWER SWITCH WAS "ON". AFTER EXTENSIVE TROUBLESHOOTING, FOUND ONE OF THE PRINTED CIRCUIT LINES WAS MELTED NEAR TO THE MOTHERBOARD AREA. SINCE THIS PRINTED BOARD IS NOT A LRU THE CUSTOMER HAS NO OTHER CHOICE BUT, REPLACE THE WHOLE ACPC ASSY.