Vintage Radio Service Manual - SIGNAL model 341-A  (Battery-Line Oprated) portable 4-tube Superheterodyne AM radio receiver. Manufactured by Signal Electronics, Inc., of New York, NY. Dated 1948. 4 pages. Original old Sams Photofact manual includes schematic, layout, alignment instructions, dial cord drive, voltage & resistance test chart, repair parts list and description. This manual would make a sensational accompaniment to your retro audio equipment.