What was found
DURING CLIMB, THE FLIGHT CREW REPORTED THAT THE CABIN WAS PRESSURIZING, BUT THAT THE CABIN PRESSURE INDICATION WAS DASHED. THE QRH WAS FOLLOWED AND THE AUTO PRESS MESSAGE CLEARED FROM EICAS, BUT THAT THE CABIN ALTITUDE INDICATION WAS STILL DASHED. THE FLIGHT THEN RETURNED TO KSDF AND AT ABOUT 1500FT ON APPROACH THE CABIN PRESSURE INDICATION RETURNED. THE PRESSURIZATION SYSTEM WAS PLACED ON MEL AFTER THE MANUAL OPERATED NORMALLY AND THE AIRCRAFT WAS RELEASED FOR REVENUE FLIGHT. THE MEL WAS CLEARED LATER THAT SAME DAY IN KSDF WHEN THE AUTO PRESSURIZATION CONTROLLER WAS REPLACED.