As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LANDING/WAITING FOR GATE IN KOA: #1 ENG GENERATOR SOURCE OFF AND GEN OFF BUS LIGHT ILLUMINATED. NO-(ZERO) VOLTS OR CYCLES INDICATED ON #1 GENERATOR. PER QRH - STARTED APU AND POWERED #1 SYSTEM W/ APU POWER. GROUNDED - YES. REMOVED AND REPLACED #1 ENGINE IDG PER B737-800 AMM 24-21-11. C/W IDG INSTALLATIONTEST, ETOPS GROUND VERIFICATION TEST SUCCESSFUL OPS TEST NORMAL PER AMM 24-11-00.