As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO FLIGHT, THE PRESSURIZATION CONTROLLER HAD BEEN CHANGED DUE TO FAILURE AND A REPAIRED UNIT INSTALLED IAW MM, 21-30-03. ALL OPS CHECKS PERFORMED WITH NO DISCREPANCIES NOTED. PREPARED FOR DEPARTURE WITH NO DISCREPANCIES. 30 MINUTES INTO FLIGHT, NOTICED CABIN ALTITUDE RISE AND STARTED AN IMMEDIATE DESCENT. AT APPROXIMATELY FL240 THE PRESSURIZATION CONTROLLER BEGAN TO WORK AND HOLD CABIN ALTITUDE. THE DECISION WAS MADE TO LAND.