As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI IN WE COULD SMELL SMOKE, TURNED PACS OFF. ON LATER TESTING IT SEEMS TO HAPPEN WHEN WE TURN THE COCKPIT PAC ON. RAN BOTH PACS WITH THE APU FOR ABOUT 3 HOURS IN ALL MODES AND CONFIGURATIONS WITH NO SMOKE OR ABNORMAL SMELLS. OPERATED BOTH PACS. WITH EACH ENGINE WITH NO DEFECTS OR SMELLS. PERFORMED ECS DUCT BURN OUT AND REPLACED BOTH COALESCER SOCKS. ALL OPS CHECKS GOOD IN REFERENCE TO CE-750 AMM 21-61-00.