As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - CREW REPORTED RIGHT CONSTANT SPEED DRIVE OVERTEMP INDICATION WITH AUXILIARY POWER UNIT ON PLACARD. ACCOMPLISHED QRH PROCEDURE AND TURNED OFF THE RIGHT GENERATOR. EMERGENCY DECLARED FLIGHT RETURNED DFW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED CONSTANT SPEED DRIVE GENERATOR. SYSTEM GROUND CHECK NORMAL OPERATION.