As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LANDED DSM UNDER AMBER ALERT DUE TO A NR 1 ENGINE VIBRATION. ACCOMPLISHED VIBRATION TROUBLESHOOTING ON THE NR 1 ENGINE AND FOUND NO DISCREPANCIES. TO ENSURE THE ENGINE WAS WITHIN ACCEPTABLE VIBRATION LIMITS AN ENGINE TRIM BALANCE WAS ACCOMPLISHED ON THE NR 1 ENGINE BY TEST CELL PERSONNEL.