Vintage Radio Service Manual - AIR CHIEF model 4-A-17 (Code No. 213-7-7270) 7-tube Superheterodyne AM radio receiver with combination phonograph record changer. Manufactured by Firestone Tire & Rubber Company, of Akron, OH. Dated 1948. 6 pages. Original old Sams Photofact manual includes schematic, layout, alignment instructions, voltage & resistance test chart, repair parts list and description. This manual would make a sensational accompaniment to your retro phono equipment.