Vintage SENTINEL models 1U-316PM, 1U-316PT, 316PT and 316PM portable Superheterodyne AM radio receiver.  Original old Sams Photofact manual includes schematic, layouts, alignment adjustments, repair parts list. 4 pages.  Dated 1948.  Sentinel Radio Corp., of Evanston, IL.  This manual would make a sensational accompaniment to your vintage audio equipment.