What was found
(CAN) IN CRUISE, CREW SMELLED AN ACRID ELECTRICAL ODOR THEN NOTICED THE NR 1 VHF COM CONTROL HEAD BLANK. CREW SAID THEY COULD STILL HEAR ATC TRANSMITTING ON THAT COM BUT DISPLAY WAS BLANK. PULLED THE CIRCUIT BREAKER FOR COM AS A PRECAUTION. MAINTENANCE FOUND NR 1 VHF COMM CONTROL HEAD HAVING BURNED ODOR. NR 1 VHF COMM CONTROL HEAD AND REPLACED AND TESTED SERVICEABLE IAW AMM 23-21-12. POWER SUPPLY FOR THE CONTROL HEAD IS INSIDE THE TRANCEIVER BOX THERFORE BOTH PARTS REPLACED AS PRECAUTIONARY. TEAR DOWN REPORTS HAVE BEEN REQUESTED.