As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FORWARD LAVATORY SMOKE DETECTOR ALARM BEGAN ALERTING AND THEN STOPPED AFTER APPROXIMATELY 20 CHIMES. NO PERSON OR USAGE HAD OCCURRED IMMEDIATELY PRIOR OR DURING. ELECTRICAL LIGHTING HAD ALSO QUIT. PERFORMED FORWARD LAVATORY SMOKE DETECTION SELF TEST IAW AMM 26-14-00. OPS CHECKED GOOD, NO FAULTS NOTED.