American-Bosch 524A Automotive Radio Schematic
June 1935 Radio-Craft

June 1935 Radio-Craft

[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Craft, published 1929 - 1953. All copyrights are hereby acknowledged.

The Antique Autoradio Madness website has an impressive collection of information on antique car radios.

Locating images of automobile radios from the 1930s through 1940s is a challenge. Sometimes one shows up on eBay, but those that do are usually in un-reconditioned condition, and often with missing components. Early car radios were composed of separate units holding the electronics, another for the power supply, and another for mounting in or under the dashboard. The antenna was often a rectangular loop run around the perimeter of the underside of the car or truck. This schematic for the American-Bosch 524A Automotive Radio appeared in a 1935 issue of Radio−Craft magazine. I found a very nice website - Antique Autoradio Madness - which has a large collection of schematics and photographs for automobile radio from all over the world. It does not have the exact model reported on here, but there was a lot of similarity between radios of the same vintage, so the information on this American Bosch model 624A shown in the thumbnail image to the left is probably quite like the model 524A.

American-Bosch 524A Radio Schematic

Remarkable improvements in car sets are indicated these diagrams of the new automotive radio receivers shown on the preceding page.

In this receiver a unique mechanical design has been utilized to secure an attractive appearance, mechanical stability and desirable service features. The circuit has been designed and adjusted for minimum internal noise and is equipped with an efficient motor ignition noise trap. The vibrator-"B" unit is of the latest, non-synchronous type, with readily adjustable contacts. The volume control is designed to maintain good bass response at low volume levels. This set is supplied with a kit of spark suppressors, etc.; the installation manual furnishes complete information on the elimination of noise due to: (1) antenna pickup; (2) antenna lead-in pick-up; and (3) noise conduction into the set via battery cable.

Voltages: Plate - V1, 215, (Osc. - 110); V2, 215; V3, 95; V4, 205. S.-G. - V1, 110; V2, 110; V4, 215. Sup.-G - V2, 10. Cath. - V1, 10; V2, 10; V3, 9.5; V4, 12.5.

Posted September 26, 2023
(updated from original post on 6/1/2016)

Radio Service Data Sheets

These schematics, tuning instructions, and other data are reproduced from my collection of vintage radio and electronics magazines. As back in the era, similar schematic and service info was available for purchase from sources such as SAMS Photofacts, but these printings were a no-cost bonus for readers. There are 227 Radio Service Data Sheets as of December 28, 2020.

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American-Bosch 524A Automotive Radio Schematic June 1935 Radio-Craft

American-Bosch 524A Automotive Radio Schematic
June 1935 Radio-Craft