As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DIRTY SOCK FUME SMELL IN COCKPIT. ISOLATED # 1 PACK AND SMELL WENT AWAY-FOUND LIGHT MUSTY SMELL FROM PACK 1 DURING APU RUN. NO SMELL FROM PACK 2. PERFORMED PACK 1 AND 2 BURN IAW AMM 21-00-00-615-002. NO SMELL NOTED AFTERWARD. R&R BOTH RECIRC FILTERS IAW AMM 21-21-41. AS PRECAUTION. NO ODORS OR FUMES AT THIS TIME. A/C OK FOR SVC.