As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WOULD NOT PRESSURIZE ABOVE 10,000 FT WENT TO MANUAL AND STANDBY POSITIONS. CABIN KEPT CLIMBING. AIR TURN BACK TO IND. REMOVED AND REPLACED RIGHT PACK VALVE PER MM 21-55. REPLACED CABIN PRESSURE CONTROLLER ADN PACK SWITCHES. OPS CHECK OK PER MM 21-31. (M)