What was found
PHX - ELECTRICAL POWER LOSS - FLT 813 - "C" - WHILE CLIMBING OUT OF PHX ENROUTE TO SFO THE APU FAILED, AIRCRAFT ALREADY OPERATING ON MEL 24-00-1 CONDITION #1 FOR #2 ENGINE DRIVEN GENERATOR INOPERATIVE, AIRCRAFT TURNED BACK TO PHX AND LANDED UNEVENTFULLY. MAINTENANCE REPLACED THE INTEGRATED DRIVE GENERATOR IAW T/C R5M24601, AND THE GENERATOR FIELD PANEL IAW BMM 31-10-00. MAINTENANCE ALSO FOUND A BENT PIN ON THE FIRE CONTROL MODULE CONNECTOR; REPAIRED THE PIN AND THE #2 ENGINE DRIVEN GENERATOR OPERATIONALLY CHECKED GOOD. THE APU INDICATED UNDERSPEED ON BITE AND WAS TROUBLESHOT IAW FAULT ISOLATION MANUAL 49-11-00, FIG 106, THE APU FUEL CONTROL UNIT WAS FOUND FAULTY AND REPLACED IAW T/C R6D49604. PART NAME; PANEL F