What was found
PILOT REPORTS LOST PRESSURIZATION AT FLIGHT LEVEL 29000 FEET. CABIN ALTITUDE STARTED TO DROP, PILOT DESCENDED TO 25000 FEET. CABIN ALTITUDE STARTED TO RISE PILOT TRIED MANUAL MODE ON THE CONTROLLER CABIN STILL CONTINUED TO CLIMB. PILOT DECLARED AND PERFORMED AN EMERGENCY DESCENT AND DROPPED TO THE PASSENGER OXYGEN MASK AND DROPPED TO FLIGHT LEVEL 10000 FEET. PILOT ALSO REPORTED THAT BOTH PACKS WERE WORKING NORMALLY AS WELL AS NR 1 PACK. MAINTENACE REMOVED AND REPLACED CPCS CONTROLLER AND SYSTEM OPERATIONAL CHECK GOOD.