Vintage Radio Service Manual - MAGIC-TONE model 504 4-tube, Superheterdyne AM Radio Receiver, also known as the " Bottle Receiver". Manufactured by  Radio Development and Research Corp., of New York, NY. 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.