Vintage Radio Service Manual - NATIONAL model NC-173R & NC-173T 13-tube five band Superheterodyne commercial radio receiver. Manufactured by National Company, of Malden, MA. Dated 1948. 8 pages. Original old Sams Photofact manual includes schematic, layout, alignment instructions, dial cord drive, voltage & resistance test chart, repair parts list and description. This manual would make a sensational accompaniment to your retro audio equipment.