What was found
DURING INTERROGATION OF FMC, CDU ENGINE FAULTS. FOUND CODE 73-21271 ON THE NR 1 ENGINE, ALTERNATOR VOLTAGE INPUT TO THE EEC IS OUT OF RANGE, LEG 0. SHORT TIME. ACFT GROUNDED. PERFORMED A RESISTANCE CHECK ON THE NR 1 ENGINE EEC ALTERNATOR AND J7 HARNESS FOR FAULT 73-21271, CHANNEL A FAULT. RESISTANCE CHECKED GOOD IAW FIM 73-27 TASK 804. REMOVED AND REPLACED THE NR 1 ENGINE EEC IAW AMM 73-21-60. PERFORMED EEC INSTALLATION TESTS AND REPAIR CONFIRMATION TEST FOR FAULT 73-21271 ALTERNATOR VOLTAGE INPUT TO EEC. ALL TESTS PASSED NO FAULTS.