What was found
AIR TURN BACK FOR SMOKE, AFT CARGO DETECTION. INBND FLT NR 2633. OTBND FLT NR 2607. FLHT CREW DISCHARGED AFT CARGO BOTTLE 1 (FIN 4005WX) & BOTTLE 2 (FIN 4010WX) IS ON A TIME DELAY CIRCUIT & DISCHARGED 1 HR LATER. ACFT GROUNDED. R & R FIRE BOTTLES IAW AMM 26-23-42-400-001, R & R HALON FILTERS IAW AMM 26-23-14-400-001, CLEANED OUT & INSP OF LINES FOR FIRE SYS IAW AMM 26-23-00-200-005-A SUBTASK 26-23-00-220-051-B, R & R OF NEW PRESSURE REDUCERS IAW AMM 26-23-18-400-001, R & R OF NEW CHK VALVES IAW AMM 26-23-21-400-001, R & R DIAPHRAM IAW AMM 26-23-25-400-001, REPLACED OF SMOKE DETECTORS. MEL 26-16-04A CN1254856 WAS PLACED & ACFT RTS.