As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF UNABLE TO PRESSURIZE AIRCRAFT. FOUND CONDITIONED AIR CHECK VALVE CRACKED AND FOUND HOLE ON FORWARD CARGO COMPARTMENT AIR SUPPLY DUCT. REMOVED AND REPLACED CHECK VALVE AND ACCOMPLISHED LEAK CHECK IAW 21-28-08. AIR DUCT REMOVED AND FORWARDED FOR REPAIR TO AVDUCT. RE-INSTALLED DUCT, LEAK CHECKED IAW 21-23-02. NO ABNORMALITIES.