As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START BUT BEFORE TRANSFERING ELECTRICAL POWER FROM THE APU GENERATOR, NR 1 GENERATOR FIELD TRIPPED ACCOMPANIED BY AN OVERVOLTAGE SYSTEM 1 ON F/E PANEL AFTER RESETTING OVERVOLTAGE AND CLOSING THE FIELD BREAKER PER ABNORMAL 4-ELEC-A-1-4 OF OPS MANUAL. THE NR 1 FIELD RETRIPPED ACCOMPANIED BY AN UNDERVOLTAGE SYSTEM NR 1. REPLACED NR 1 GENERATOR VOLTAGE REGULATOR, SYSTEM OPS CHECKED NORMAL IAW M/M 24-20-0.