As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 GENERATOR DRIVE LIGHT ILLUMINATED PRIOR TO ENTERING ETOPS. DISCONNECTED GENERATOR. APU SUPPLIED POWER. LEFT AC INTEGRATED DRIVE GENERATOR (IDG) FAILURE. REPLACED THE LEFT IDG. CARRIER SHAFT FROZEN. REPLACED THE SHAFT AND OVERHAULED THE IDG.