As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIREP SMELL OF ELEC BURNING IN FLIGHT. CREW ELECTED TO RETURN TO DEPARTURE AIRPORT & LANDED WITHOUT INCIDENT. MX VERIFIED THE RECIRCULATION FAN HAD INTERMITTENT GRINDING SOUND & SEIZING, DEFERRED. ACFT RETURNED TO BASE WITHOUT INCIDENT. FAN TO BE REPLACED.