As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
R1 GENERATOR DRIVE LIGHT ILLUMINATED. FOLLOWED QRH, DISCONNECTED DRIVE. AN EMERGENCY WAS DECLARED. AIRCRAFT RETURNED TO DEPARTURE WITHOUT FURTHER INCIDENT. THE AIRCRAFT GROUNDED. REMOVED AND REPLACED RIGHT ENGINE R1 VARIABLE FREQUENCY STARTER GENERATOR IAW AMM 24-21-09-FOB 720A-A.