As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED, CABIN PRESSURE AT 9.2 DIFFERENTIAL AT FLT 330. SWITCHING TO AUTO AND STANDBY WOULD NOT LOWER CABIN PRESSURE DIFFERENTIAL. OUTFLOW VALVE WOULD NOT WORK IN MANUAL AC OR DC. HAD TO CHANGE ALTITUDE TO LOWER CABIN PRESSURE. REPLACED NR 1 AIR DATA COMPUTER AND THE AUTO PRESSURE CONTROLLER PANEL.