Original vintage 1930s radio service bulletin binder compiled for use by a radio service technician. This loose-leaf reference manual contains factory-issued service bulletins, wiring diagrams, schematics, voltage charts, alignment procedures, and parts information for a variety of early tube radios. Manufacturers represented include Philco, Emerson, Arvin, and likely others. Features numerous detailed fold-out schematics and technical service information used by authorized radio repair shops during the Golden Age of radio. The binder is personalized to the original owner, L. Tompkins, adding to its historical appeal as a genuine working technician’s reference rather than a later reprint. Approximately 11.5″ x 9.5″. Good vintage condition with expected age-related wear to the binder and pages. Please review all photographs carefully, as they are part of the description. A fantastic piece of early electronics history, ideal for antique radio collectors, restorers, historians, and anyone interested in vintage American technology and service literature.