What was found
PILOT REPORTED AFT J-BOX CB ANNUNCIATOR ILLUMINATED IN-FLIGHT. FOUND BAGGAGE HEAT AND APU AUX HYD PUMP CONTROL CB'S LOCATED IN AUX DC J-BOX TRIPPED. USED AN INSP MIRROR AND FOUND NO OBVIOUS WIRING DEFECTS. AFTER SEVERAL HRS OF SYS T/S AFT J-BOX CB ANNUNCIATOR ILLUMINATED. SMOKE WAS EMITTING FROM AUX J-BOX, ALL SYSTEMS WERE SHUT DOWN, FIRE WAS EXTINGUISHED. DURING AUX J-BOX REMOVAL, THE SELF-LOCKING NUT SECURING TERMINAL LUG OF MAIN POWER CABLE WAS FOUND LOOSE. HEAT GENERATED FROM ADDED RESISTANCE TRIPPED CB'S AND CAUSED FIRE. AUX J-BOX PREVIOUSLY REMOVED 1-97 TO ACCOMPLISH SB 29-9. PHASES 1-5 COMPLETED 2-98.