What was found
SLC - FLT 865 - ON CLIMB-OUT, FLIGHT ENGINEER UNABLE TO CONTROL CABIN IN AUTO, STANDBY, OR MANUAL (OUTFLOW VALVE IN FULL CLOSED POSITION WITH CABIN CLIMBING). FOUND RIGHT FORWARD PACK VALVE INOPERATIVE. REPLACED RIGHT FORWARD PACK VALVE AND RAN RIGHT PACK, OPERATIONS CHECKED NORMAL. ALSO PRESSURIZED AIRCRAFT ON GROUND AND FOUND NO AIR LEAKS. AIRCRAFT PRESSURIZED NORMALLY. (X)