What was found
ORD - FLT 1828 - AFTER TAKEOFF, LEFT AFT LAVATORY SMOKE DETECTOR SOUNDED. A SLIGHT ODOR WAS DETECTED IN THE CABIN, AIRCRAFT RETURNED TO ORD AND LANDED WITHOUT INCIDENT. REMOVED ALL LAVATORY WALLS AND CEILING PANELS, CHECKED ALL LIGHTS, SIGNS, FLUSH MOTOR, ELECT WIRING AND CONNECTORS. FOUND NO SIGN OF ELECTRICAL DAMAGE OR SMOKE SMELL. REPLACED LEFT LAVATORY SMOKE DETECTOR, ALL TESTS CHECKED NORMAL. SYSTEM GROUND CHECKED, NORMAL OPERATION. (X)