What was found
EN ROUTE, PHL TO SFO - DURING FLIGHT, THE APU AUTO-SHUTDOWN WITH THE NR 1 ENGINE IDG ON MEL. FLIGHT CONTINUED TO DESTINATION AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE SERVICED THE APU WITH 2.5 QUARTS OF OIL AND TIGHTENED A LINE TO THE APU FUEL CONTROL UNIT. ALSO, REPLACED THE FILLER COUPLING ON THE NR 1 ENGINE IDG. OPERATIONALLY AND LEAK CHECKS OK.