What was found
THE CREW ADVISED DISPATCH THAT THE AIRCRAFT WAS UNABLE TO PRESSURIZE AND WAS LEVELING OFF AT 10,000. CREW COMPLIED WITH QRH AND SWITCHED TO CONTROLLER 2 AND MANUAL MODE; NEITHER CORRECTED THE ISSUE. THE FLIGHT BURNED OFF FUEL AND RETURNED TO CAE. RTN-CABIN W/N PRESSURIZE REC'D CABIN ALT CAUTION MSG RAN CABIN ALT QRH CABIN WOULD SILL NOT PRESSURIZE DELTA P REMAINED AT.1 ENTIRE TIME SWAPPED CONTROLLERS AND TRIED MANUAL, AIRCRAFT WOULD STILL NOT PRESSURIZE. NO ASSOCIATED MSG'S.