What was found
(CAN) DURING A ROUTINE TAKEOFF, NOTED WHEN THE WHEELS BROKE GROUND, THE ACFT IMMEDIATELY WENT INTO EMERGENCY PRESSURIZATION MODE. THE FLIGHT CREW COULD NOT TURN IT OFF. ELECTED TO TURN AROUND AND LAND BACK AT DEPARTURE, THE LANDING CONTINUED WITHOUT COMPLICATIONS. TROUBLESHOT, AND FOUND THAT THE CIRCUIT BREAKER THAT CONTROLS THE AIR CYCLE OVERHEAT SYS HAD BEEN DAMAGED DURING MAINTENANCE THAT WAS JUST PREVIOUSLY ACCOMPLISHED ON THE ACFT FOR AN UN RELATED SNAG. THE CIRCIUT BREAKER WAS REPLACED WO CSV2884, THE SYSTEM WAS GROUND FUNCTION CHECKED SERVICEABLE.