As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON T/O LEFT ENGINE VIBE AT 2.1 - RETURN TO ATL. REMOVED BLADES, PINS AND BUMPERS. PERFORMED GENERAL VISUAL INSPECTION OF FAN BLADES. RE-MAPPED FAN BLADES, LUBRICATED RETAINING PINS, INSTALLED FAN BLADES, PERFORMED CHECK OF THE ENGINE N1 VIBRATION LEVEL IAW TASK CARD TSWS CF34-8 FAN VIBE. AIRCRAFT RETURNED TO SERVICE. THIS WAS AN AIR RETURN.