As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE DEVELOPED VIBRATION AT FL390. VIBRATION FOLLOWED THROTTLE MOVEMENT AND FELT IN CABIN WITH SELECTOR IN (LOW) AND EITHER (A) OR (B) LATCHED. INSPECTED CHIP DETECTORS AND FILTERS, NO DEBRIS NOTED. INSP ENGINE FOR DAMAGE, NONE NOTED. COMPLIED WITH BOROSCOPE, NO DEFECTS NOTED. PERFORMED GROUND SURVEY AND TRIM BALANCE. COMPLIED WITH CLAPPER LUBE. ENGINE OK FOR SERVICE.