What was found
AFTER DEPARTURE, NOSE LANDING GEAR FAILED TO RETRACT. SEVERAL ATTEMPTS TO RETRACT WERE MADE WITH NO SUCCESS. AN UNEVENTFUL NORMAL LANDING WAS MADE. AFTER LANDING, GEAR PINNED AND A VISUAL INSPECTION MADE. MAIN GEAR DOORS WERE OPEN AND THE NOSE GEAR DOORS MOSTLY CLOSED AND MOVEABLE BY HAND. ATTEMPTS WERE MADE TO OPERATE THE DOORS WITH THE GROUND SERVICE VALVE WITHOUT SUCCESS. MANUFACTURER RESET LANDING GEAR DUMP VALVES, PERFORMED LANDING GEAR EMERGENCY EXTENSION IAW CMP 323004, SERVICED RESERVOIR & LANDING GEAR BOTTLE. NO DEFECTS WERE NOTED. AIRCRAFT CONTINUED ON TO DESTINATION AFTER REPAIRS AT MANUFACTURER, WITH NO FURTHER ISSUES.