What was found
ON CLIMBOUT, RECEIVED ECAM MESSAGES (ELECT DC ESSENTIAL BUSS SHED) & (CIRCUIT BREAKER TRIPPED L AVIONICS BAY), TURNED BACK FOR REPAIR. MX TROUBLESHOT WIRING FROM CIRCUIT BREAKER (1PH) TO GROUND, NO DEFECTS NOTED. R & R CIRCUIT BREAKER (1PH), RELAY (31XE), & SINGLE POLE 100A CONTACTOR (8PH) IAW AMM. AFTER CONTACTOR (8PH) REMOVED, LOOSE PARTS HEARD RATTLING INSIDE, CONTACTOR HOT TO TOUCH. DC BUSS SYS OPS CK GOOD. VENDORS FAILURE ANALYSIS OF CONTACTOR (8PH) CONFIRMED REASON FOR REMOVAL, DISASSEMBLY FOUND ADJUSTMENT NUTS LOOSE AND THE SUPPORT USED TO ATTACH PARTS WAS FOUND TO BE DISTORTED, UNIT WAS ALSO FOUND TO HAVE INTERNAL CONTAMINATION ON INSIDE COVER & WIRING. UNIT DEEMED UN-REPAIRABLE AND WAS SCRAPPED.