As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER START OF THE RIGHT ENGINE NOTICED TO HAVE N2 VIBS OF 5.0 AND CAN BE FELT. UNUSUAL SOUND ALSO. RETURNED TO GATE. NO METAL IN TAIL PIPE. CHIP DETECTORS CLEAN BUT ENG HAS RUMBLE SOUND WHEN RUNNING. BOROSCOPE REVEALED 1ST HPC BLADE BROKEN OFF. ENGINE CHANGE IN PROGRESS.