What was found
NEW AIR CONDITIONER COMPRESSOR. POST-MAINTENANCE OPS CHECK WAS GOOD. ON THE RETURN LEG OF THE FIRST FLIGHT AFTER COMPRESSOR INSTALLATION, THE CREW STARTED TO DETECTED AN ODOR. TURNED OFF THE A/C AND THE ODOR WENT AWAY. DISCOVERED OVERHAULED AIR CONDITIONER COMPRESSOR CLUTCH THAT WAS INSTALLED THE DAY BEFORE HAD FAILED. A/C COMPRESSOR WAS REMOVED AND REPLACED WITH ANOTHER OVERHAULED COMPRESSOR.