Vintage Radio Service Manual - DEWALD model B-510 5-tube AC-DC operated multi-band Superheterodyne AM SW radio receiver.  Manufactured by Dewald Radio Manufacturing Company, of Long Island City, NY. Dated 1948. 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.