What was found
IAH - FLIGHT 2259 - DURING CRUISE, THE CREW REPORTED THAT THE AIRCRAFT CABIN RATE OF CHANGE BECAME ERRATIC. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE DIGITAL PRESSURE CONTROLLER, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE. (A)