As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, ACFT FAILED TO PRESSURIZE. CABIN WAS CLIMBING AT SAME RATE AS ACFT. WE GOT CABIN ALT CAUTION . RAN QRH. PRESSURIZATION DID NOT RESPOND IN MANUAL MODE. ACFT DELTA P WAS AT ZERO. RETURNED TO LAND. ACFT RETURNED TO DEPARTURE AFTER T/O -- EMERGENCY DECLARED AS A PRECAUTION. REMOVED AND REPLACED PRESSURE CONTROL PANEL , OP CHECKS GOOD IAW AMM 21-31-10. NO FURTHER DEFECTS, ACFT PRESSURIZED NUMEROUS TIMES WITH APU AND ENGINE BLEEDS.