What was found
IN CRUISE FLIGHT AT FL380, CREW FELT A VIBRATION, IT CONTINUED TO GET STRONGER. CREW REQUESTED ATC TO LAND AT NEAREST SUITABLE AIRPORT BUT DID NOT DECLARE AN EMERGENCY. FLIGHT CREW DETERMINED THAT NR 1 GENERATOR WAS GONG BAD AND DIVERTED THE AC. APPROACH WAS MADE WITH THE LT ENG IN IDLE, AC MADE AN UNEVENTFUL LANDING WITH NO INJURIES TO PASSENGERS OR CREW. CONTACTED INSP AND MAINT OF LT ENGINE AND STARTER/GEN. ON INSP, FOUND THAT LT STARTER/GEN HAD FAILED, BRGS WERE WORN. REMOVED AND REPLACED LT STARTER/GEN, RT SERVICEABLE STARTER/GEN AS WELL AS FOR TIME. PERFORMED AN OPS CHECK OF BOTH STARTER/GENS WITH NO DISCREPANCIES NOTED. (K)