RCA Victor Model C9-4, 9-Tube, 3-Band Superheterodyne
Radio Service Data Sheet
January 1936 Radio-Craft

January 1936 Radio-Craft

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 RCA Victor Model C9-4 is a 9-tube, 3-band superheterodyne console model radio made in the mid 1930s. A Radio Service Data Sheet for it appeared in the January 1936 issue of Radio-Craft magazine. The image to the left was found on the RadioMuseum.org website. FM broadcasting was not in common use yet, so only AM bands and some shortwave bands were available. In fact, 1936 was the year that frequency modulation (FM) inventor Edwin H. Armstrong first demonstrated his newfangled concept that largely solved the electrical static noise problem cause by lightning, motor brushes, arcing overhead power lines, etc. I post these Radio Service Data Sheets for the benefit of hobbyists who work hard to restore and repair these monuments to early radio progress.

RCA Victor Model C9-4, 9-Tube, 3-Band Superheterodyne Radio

Before aligning this set, use tuning wand to be sure alignment is required. I.F. is aligned at 460 kc., by means of an oscillator. Use an output indicator or an oscilloscope. Adjust trimmers C29, C30, C24, and C25 in that order. Align band A at 1,720 kc., by adjusting C20, C10 and C3 to produce maximum output.

Tune oscillator to 600 kc., adjust receiver to resonance. regardless of dial setting, and adjust C19. Recheck C20. Band B is aligned at 6,132 kc., by setting test connections oscillator at this frequency and turning receiver station to this setting.

Posted November 21, 2019
(updated from original post on 12/5/2016)

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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RCA Victor Model C9-4, 9-Tube, 3-Band SuperheterodyneRadio Service Data SheetJanuary 1936 Radio-Craft

RCA Victor Model C9-4, 9-Tube, 3-Band Superheterodyne
Radio Service Data Sheet
January 1936 Radio-Craft