If it is available at all, a given part may be available here;
https://www.yamaha24x7.com/YamahaOMS/BasePages/Login.aspx?ReturnUrl=%2fyamahaoms%2fdefault.aspx
https://www.yamaha24x7.com/YamahaOMS/BasePages/Login.aspx?ReturnUrl=%2fyamahaoms%2fdefault.aspx