Vintage Radio Service Manual - AIR CHIEF model 4-B-6 (Code 117-7-PM18) 6-tube car automotive AM radio receiver. Manufactured by Firestone Tire & Rubber Company, of Akron, OH. Dated 1947. 4 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 audio equipment.