What was found
DTW - FLT 1302 - EN RUOTE DFW/DTW - DURING CRUISE AT FL 330, UNABLE TO MAINTAIN CABIN PRESSURIZATION. ACCOMPLISHED EMERGENCY DESCENT, DROPPED ALL PASSENGER OXYGEN MASKS AND AIRCRAFT PROCEEDED TO DTW, LANDING WITHOUT INCIDENT. REPLACED NR 1 PRESSURIZATION CONTROLLER. ACCOMPLISHED PRESSURIZATION CHECK WITH NO DEFECTS FOUND. PLACARDED PASSENGER OXYGEN SYSTEM AND AIRCRAFT RETURNED TO REVENUE SERVICE WITH ALTITUDE RESTRICTION. SUBSEQUENTLY REPLACED OXYGEN CYLINDERS AND MASKS AT TUL/30. ACCOMPLISHED DROP CHECK AND LEAK CHECKS WITH NO DEFECTS FOUND. OXYGEN SYSTEM PLACARD REMOVED. (M)