General Motors 7-Tube Superheterodyne Chasses S1A 60 Cycles
and S1B 25 Cycles Radio Service Data Sheet
January 1932 Radio-Craft

January 1932 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.

This is interesting. The title for the General Motors S1B radio says it is a 25-cycle model, as compared to the S1A, 60-cycle model. According to an IEEE Xplore paper, "At 8:53 PM on 12 October 2006, a 66-kV circuit breaker tripped and locked out at the Harper Substation in Niagara Falls, New York, due to downed transmission conductors near Buffalo, New York. That event marked the end of over 111 years of 25-Hz alternating current (ac) electric power service on the American side of the Niagara Frontier." 25 Hz was considered a good, low frequency for conversion to DC, which was in common use in the early 20th century. The world did not standardize on 60/50 Hz until after World War II.

General Motors 7-Tube Superheterodyne Chasses S1A 60 Cycles and S1B 25 Cycles
Radio Service Data Sheet

Posted March 2, 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 255 Radio Service Data Sheets as of April 30, 2025.

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General Motors 7-Tube Superheterodyne Chasses S1A 60 Cyclesand S1B 25 Cycles Radio Service Data SheetJanuary 1932 Radio-Craft

General Motors 7-Tube Superheterodyne Chasses S1A 60 Cycles
and S1B 25 Cycles Radio Service Data Sheet
January 1932 Radio-Craft