What was found
(CAN) FLIGHT CARRIED OUT MAR. 5, 2007, NR 2 COMM DISPLAY WENT BLANK. CONTROL HEAD REPLACED WITH LOANER UNIT, GROUND TESTED OK. NEXT FLIGHT AIRCRAFT TOOK OFF AND UPON ROTATION THE CREW SMELLED SOMETHING BURNING AND SAW SMOKE COMING FROM THE NR 2 COMM CONTROL HEAD. AIRCRAFT RETURNED TO BASE. CONTROL HEAD REMOVED FOR REPAIR AND INVESTIGATION. FOUND WIRE P/N J176037 IN NOSE AVIONICS BAY GOING FROM RELAY J304 TO TRANSCEIVER TRAY WITH CONTINUITY TO GROUND. WIRE REPAIRED AND ORIGINAL CONTROL HEAD INSTALLED AFTER REPAIR, COMM OPERATED FOR 2 HOURS ON THE GROUND WITHOUT FAULT. NO PROBLEMS REPORTED THE SUBSEQUENT FLIGHT. (TC NR 20070308002)