As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SUPPLEMENTAL A/C. SMOKE SMELL IN CABIN DETERMINED SMOKE SMELL TO BE R134A REFRIGERANT THAT LEAKED FROM SUPP AC. CAPTAIN REPORTED SMELL WENT AWAY WHEN AC WAS SWITCHED OFF. SUPP AC DEACTIVATED AND DEFERRED PER MEL 21-50-02. NO SMOKE SMELL NOTED WHILE A/C WAS GROUND RAN FOR 15 MINUTES WITH LT AND RT BLEEDS ON. REPLACED COMPRESSOR BELT PN 232L100, COMPRESSOR PN ON/OFF 1134160, SN ON 1665, S/N OFF 1856, REPLACED RECEIVER DRYER PN 1134192-2.