As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2193, ON APPROACH THE LAVATORY SMOKE DETECTOR WENT OFF TWICE. BOTH TIMES THE FLIGHT ATTENDANT REPORTED NO INDICATIONS OF SMOKE. AIR WAS SMOOTH AND THE BLEEDS WERE ON MAX. MAINTENANCE REPLACED THE AIR CYCLE MACHINE, CONDENSER/MIXER AND HEAT EXCHANGER. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.