What was found
FLIGHT 5319, EWR TO STL - CREW REPORTED THAT DURING CLIMB AT ABOUT 5,000 FT THE CABIN DIFFERENTIAL, CABIN RATE OF CLIMB, AND CABIN ALTITUDE INDICATIONS DASHED OUT. THE CREW TRIED MANUAL MODE WITH NO HELP. THE AIRCRAFT RETURNED TO EWR AND LANDED WITHOUT INCIDENT. MAINTENANCE RESET POWER TO THE AIRCRAFT AND ALL PRESSURIZATION INDICATIONS RETURNED TO NORMAL. PRESSURIZATION CHECKS WERE PERFORMED WITH NO FURTHER DEFECTS NOTED.