As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT 826EX HAS SHOWN A SEVERAL DAY HISTORY OF THE LAVATORY SMOKE DETECTOR ALARMING. THE DETECTOR WAS REMOVED AND REPLACED, OPERATIONAL CHECKS WERE GOOD. THEN THE DETECTOR WOULD ALARM AT A LATER TIME. MAINTENANCE TROUBLESHOT IT DOWN TO THE AIR CYCLE MACHINE PRODUCING ENOUGH FUMES TO TRIP THE DETECTOR ALARM. AIR CYCLE MACHINE WAS REPLACED AND SYSTEM OPERATIONAL CHECK GOOD. AIR CYCLE MACHINE IN QUESTION WAS ALSO DUE TIME CHANGE.