As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PER WORK ORDER T/C# 78273000 FOUND #1 ENG MSG# 73-21271 "THE ALTERNATOR VOLTAGE INPUT TO THE EEC IS OUT OF RANGE" ON FLIGHT LEG#3 IS A SHORT TIME FAULT. GROUNDED - YES. REMOVED AND REPLACED J8 HARNESS ON #1 ENGINE IAW B737-900 AMM 73-21-06. HARNESS CHECKS GOOD PER EEC TEST AMM 73-21-00-700-804-F00 AND TEST 12 ACTUATORS TEST AMM 71-00-00-700-807-F00. REPAIR CONFIRMATION GOOD PER B737-900 FIM 73-27 TASK 804. ETOPS GROUND VERIFICATION GOOD.