What was found
(CAN) HELICOPTER OPERATOR DETECTED ENGINE VIBRATION. TROUBLESHOOTING DETERMINED THE STARTER WAS THE CAUSE. ST/GEN RECEIVED BY O/H AMO FOR INSPECTION/REPAIRS. FOUND THE DRIVE END, ENDBELL BEARING LINER HAS BROKEN LOOSE IN ITS ENDBELL CASTING. BEARING LINER RATTLES IN THE CASTING, LIKE A TAMBOURINE. THERE IS A STEEL PIN IN ALL THESE ENDBELLS TO REDUCE WEAR BETWEEN THE LINER AND ENDBELL WHEN THIS FAILURE OCCURS. A SERVICE BULLETIN, SB150SG106 IN JUL 1982 WAS ISSUED FOR FIELD MODIFICATION, AND NEW PRODUCTION INCLUDES THE PIN. THE PURPOSE WAS TO "STRENGTHEN THE BOND BETWEEN LINER AND ENDBELL." NO OTHER DAMAGE OR OUT-OF-BALANCE PART WAS FOUND. REPAIRS BEING DONE FOR RETURN TO SERVICE.