As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT ON CLIMBOUT AUTO PRESSURIZATION FAILED AND ALL INDICATIONS BLANKED OUT. THEY SWITCHED TO MANUAL MODE BUT STILL WOULD NOT PRESSURIZE. THE AIRCRAFT THEN RETURNED TO FIELD AND LANDED WITHOUT INCIDENT. THE AUTO PRESSURIZATION SYSTEM WAS PLACED ON MEL AND THE AIRCRAFT WAS RETURNED TO SERVICE. THE PRESSURIZATION MEL WAS CLEARED IN KCMH ON 5/1/2011 WHEN THE DIGITAL PRESSURE CONTROLLER WAS REPLACED.