As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED THAT THE CABIN FAILED TO PRESSURIZE AFTER TAKEOFF. THEY REMAINED AT 9000' ALTITUDE AND RETURNED FOR A NORMAL LANDING AT KORL. THE MAINTENANCE PROVIDER TROUBLESHOT AND DETERMINED THAT THE CABIN PRESSURE CONTROLLER AT FAULT. THE PRESSURE CONTROLLER WAS REMOVED AND A OVERHAULED UNIT WAS INSTALLED. OPS CHECKS WERE SATISFACTORY, AND THE AIRCRAFT WAS RETURNED TO SERVICE.