As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BWI/BOS - FLT 728 - AFTER DEPARTURE, THE LEFT ENGINE GENERATOR TRIPPED OFF-LINE. ATTEMPTS TO RESET WERE UNSUCCESSFUL. THE APU WAS ON MEL LEAVING ONLY THE RIGHT ENGINE GENERATOR TO POWER THE AIRCRAFT. THE AIRCRAFT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LEFT GENERATOR CONTROL PANEL AND THE BUSS CONTROL PANEL. REF: OPERATOR CONTROL NR USAAD98186.