As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE VIBRATES STARTING AROUND 92 PERCENT N1 AND INCREASES IN INTENSITY. AROUND 95-96 PERCENT NI, IT APPEARS TO HAVE A PHASE OR OUT OF SYNC. BEAT. TURNING OFF BLEEDS, HYDRAULIC OR ELECTRICAL POWER HAS NO EFFECT. VIBRATION WAS ISOLATED TO THE FAN ROTOR. TRIM BALANCE OF THE FAN WAS PERFORMED REDUCING THE VIBRATION LEVEL TO WITHIN ACCEPTABLE LIMITS.