As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 2 ENGINE HAD SEVERE VIBRATION ON DESCENT FROM 29,000 FT. ENGINE PARAMETERS WERE ALL OK EXCEPT N1 NR1 85 PERCENT, NR 2 60 PERCENT VIBRATION STOPPED WHEN THROTTLE BOUGHT BACK BELOW 53.5 PERCENT. FUEL DUMPED. NORMAL LANDING. TROUBLESHOT TO FAULTY IP CHECK VALVE. REPLACED VALVE IAW MM 36-11-13. ENGINE RUN IAW MM 72-00-00. NO VIBRATION NOTED. PRECAUTIONARY BORESCOPE ACCOMPLISHED OK. AIRCRAFT RETURNED TO SERVICE.