What was found
WHILE ENROUTE, THE CREW NOTICED THAT BOTH COMM 1 AND 2 WERE TRANSMITTING ALTHOUGH NEITHER OF THE MIC SWITCHES HAD BEEN DEPRESSED. THE CREW TURNED THE RADIOS OFF AND THEN BACK ON. THE MALFUNCTION APPEARED TO CORRECT ITSELF. THE CREW ALSO OBSERVED THAT WHEN THE CAPTAINS WAFER SWITCHES WAS PLACED IN COMM 2 BOTH RADIOS WERE AGAIN TRANSMITTING. ABOUT 1 MINUTE AFTER TURNING THE RADIOS BACK ON THEY REALIZED THAT THEY WERE NO LONGER ABLE TO TRANSMIT TO AIR TRAFFIC CONTROLLER ON EITHER RADIO. THEY SQUAWKED 7600 AND PROCEEDED BACK UNEVENTFULLY. THE CREW MAINTAINED CONTACT THE ENTIRE WAY AND THEY WERE ABLE TO LAND WITH NO FURTHER INCIDENT. MAINTENANCE REPLACED THE AUDIO CONTROL PANEL AND DID A SYSTEM OPERATIONAL CHECK.