What was found
(CAN) WHILE AIRCRAFT PARKED ON APRON , UPON CREW ARRIVAL TO GET READY FOR DEPARTURE , THE CREW NOTICED SEVERAL CIRCUT BREAKERS WERE POPPED AND THE ATTEMPT TO RESET WAS NOT SUCCESFUL . MAINTENANCE SUSPECT THE FAULT TO BE WITH THE GROUND POWER UNIT WHICH WAS ATTACHED TO AIRCRAFT , HOWEVER THE FOLLOWING PARTS NEEDED TO BE REPLACED PIROR TO RETURN AIRCRAFT TO SERVICE 1- BOTH FUEL FLOW INDICATORS P/N SEL-OC8J 2- CABIN PRESSURE CONTROLLER P/N SET LOCH20F 3- FLIGHT. GUIDANCE CONTROLLER P/N 7003975-901