As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FA REPORTED AN ALARM TYPE SOUND IN AFT GALLEY DURING FLIGHT, SOUND CONTINUED ON GROUND AFTER ENGINE SHUTDOWN. REMOVED & REPLACED THE LAVATORY & GALLEY EXTRACT FANS IAW AMM 21-23-51. PERFORMED OPS TEST OF THE PACK TEMP-CONTROL SYSTEM IAW AMM 21-61-00. TESTED OK.