What was found
NR 2 ENGINE VIBRATION MONITOR INDICATED 2.3 AT HIGHEST LEVEL IN CRUISE FLIGHT. STAYED CLOSE TO 2.0 BALANCE OF TIME. ALL OTHER ENGINE INDICATIONS WERE NORMAL. ACFT GROUNDED. REF AMM TASK 71-00-00-800-806-F00, ENGINE OPERATION LIMITS VIBRATION LEVEL ABOVE 2.0 BUT LESS THAN 3.0 REQUIRES FAN TRIM BALANCE ON BOARD PROCEDURE AT NEXT MAINTENANCE STA OVERNIGHT, RON, TASK 71-00-00-750-808-F00, NO HISTORY ENG VIBE 90 DAYS. ACCOMPLISHED FAN TRIM BALANCE OTBD PROCEDURE IAW MM71-00-00-750-808-F00, TEST 14B. CHANGED WEIGHTS IAW SOLUTION AS REQUIRED.