What was found
FLT 416 - MDW - AIR RETURN, LANDING UNEVENTFUL. AT ABOUT 4000 FT AFTER TAKEOFF, THE FLIGHT ATTENDANT REPORTED THAT A SMOKE DETECTOR WENT OFF. LIGHT FLASHING AND HORN GOING. DEFERRED PER MEL 26-16, CI M603392 AND M603393 ASSIGNED. REF MEL 26-16, M603392 AND M603393. FOUND SMOKE DETECTOR CONTROL PANEL HAD ELECTRICAL FAULT. ACCOMPLISHED EO 973726A037, DEACTIVATING HARD-WIRED FORWARD AND AFT LAVATORY SMOKE DETECTOR SYSTEM, AND INSTALLING SELF CONTAINED BATTERY POWERED DETECTORS, 1 IN EACH LAVATORY. (M)