What was found
AT FL 300 IN LIGHT ICING RIGHT ENGINE PRODUCES HIGH VIB N1 (6.8) USED QRH HIGH ENG VIB PROCEDURE TRIED 4 TIMES AND AFTER LEAVING ICING, N1 VIBE DID NOT GO AWAY. F/A INFORMED ME THEY FELT UNUSUAL VIBRATIONS IN GALLEY. SHUT ENGINE DOWN AT 280 AND LANDED IN MEM. CORRECTIVE ACTION: PERFORMED GENERAL VISUAL INSPECTION OF RIGHT ENGINE INLET & EXHAUST NO DEFECT NOTED. INSPECTED MASTER MAGNETIC CHIP DETECTOR NO DEFECT FOUND AMM 72-00. INSPECTED NOSE CONE ASSEMBLY FOUND SEAL LOOSE UNSECURED. REMOVED AND REPLACED NOSE CONE ASSEMBLY PER AMM 72-38, OPS CHECK GOOD.