What was found
(CAN) REQUESTED AN IMMEDIATE DESCENT AND WAS CLEARED TO 3000` FROM 17000`. PILOT REPORTED THAT THE ACFT WAS HAVING AN ELECTRICAL ISSUE WITH RADIOS AND THERE WAS A FAINT ODOR OF SMOKE IN COCKPIT. PILOT DID NOT DECLARE AN EMERGENCY AND INDICATED THAT THE PROBLEM WAS RESOLVED A SHORT TIME LATER. FLIGHT LANDED AT 1058Z WITHOUT FURTHER INCIDENT. MAINTENANCE WAS DISPATCHED TO MEET THE ACFT. UPON ARRIVAL THE CREW INDICATED TO MAINTENANCE THAT THE NR 2 COMM WAS UNSERVICEABLE. MAINTENANCE POWERED UP THE ACFT SYSTEMS AND CONFIRMED THE 2 COMM TO BE UNSERVICEABLE. THE SUBJECT CONTROL HEAD WAS REMOVED AND A BURNING ODOR WAS EVIDENT. A NEW COMM CONTROL HEAD WAS REPLACED AND ONCE POWER WAS APPLIED THIS COMM ALSO FAILED AFTER APPROXIMATELY 15 MINUTES. MAINTENANCE SUSPECTED NR 2 TRANSCEIVER AT FAULT, IT WAS REPLACED WITH A SERVICEABLE UNIT. COMM NR 1 WAS PLACED IN THE NR 2 COMM POSITION TO ISOLATE SNAG. POWER WAS APPLIED AND THE COMM CONTROL HEAD FAILED AGAIN. A COMPLETE INSPECTION OF THE NR 2 COMM COMPONENTS & CIRCUITRY WERE TESTED FOR CONTINUITY, POWER & GROUND WITH NO FAULTS NOTED IAW WIRING INTERFACE DWG 129-340003, SHEET 2. ADDITIONAL TROUBLESHOOTING WAS CARRIED OUT WHICH REVEALED A DAMAGED, BENT GROUNDING STRAP ON THE NR 2 TRANSCEIVER RACK WHICH WAS REPLACED. FUSE F5 WAS ALSO FOUND BLOWN ON PC BOARD, A017, WHICH WAS REPLACED WITH NEW. A NEW COMM CONTROL HEAD WAS INSTALLED WITH SYSTEM AND FUNCTION CHECKS CARRIED OUT WITH NO ADDITIONAL FAULTS NOTED.