As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WOULD NOT PRESSURIZE IN AUTO AFTER TAKEOFF. FLIGHT RETURNED TO MEM AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED CONTROLLER, PRE-PRESSURE CONTROLLER AND AMPLIFIER; ALL WITH NO HELP. REPLACED OUTFLOW VALVE ACTUATOR. OPERATIONAL CHECK NORMAL. AIRCRAFT RETURNED TO SERVICE.