RIGOL Technologies (test equipment) - RF Cafe

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RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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Stromberg-Carlson Nos. 230 and 231 Series
Radio Service Data Sheet
November 1937 Radio-Craft

November 1937 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.

I have been scanning and posting Radio Service Data Sheets like this one featuring the Stromberg-Carlson Nos. 230 and 231 Series for many years now. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. This 231R version is unique with its half-round configuration meant to sit at the side if a sofa or chair (click on thumbnail for more info). It could pass today as a room humidifier. A running list of all data sheets can be found at the bottom of the page to facilitate a search.

See Tom Bavis' AudioPhool.com website for an extensive collection of Stromberg-Carlson photos, datasheets and Sam's Photofacts files.

Stromberg-Carlson Nos. 230 and 231 Series

Intermediate-Frequency Adjustments. The intermediate frequency used in these receivers is 465 kc. In making these circuit adjustments always align the circuits in the order given in these instructions.

(1) Operate the "Range" switch of the receiver to the "Autorange position. Set the receiver's tuning dial at its extreme low-frequency position, and operate the tone control knob to the "normal" position. Rotate the volume control knob to its maximum clockwise position; (2) Apply between the chassis and the control grid of the 6A8 tube, a modulated signal of 465 kc. from a good test oscillator, using a 0.1-mf. condenser in series with the signal lead. Do not remove the control-grid lead connecting to this tube; (3) Now align the I.F. circuits in the following manner: Secondary of 2nd I.F.; primary of 2nd L.F.; secondary of 1st L.F.; primary of 1st I.F.; adjusting the circuits to obtain maximum reading on the output meter, reducing the output of the test oscillator as required.

Alignment of "C" Band. In aligning the R.F. circuits for this range, replace the 0.1-mf. condenser which was placed in series with the test oscillator's output lead for the L.F. alignments, with a 400-ohm carbon resistor. This lead should then be connected to the antenna binding post. (1) Operate the range switch on the receiver chassis to the "C" position, and set the test oscillator's frequency and the receiver's tuning dial to 17 megacycles; (2) Adjust the oscillator's "C"-band trimmer for maximum output; (3) ;Adjust the antenna's "C"-band trimmer for maximum output, at the same time rock the gang tuning condenser back and forth, through resonance, until maximum output is obtained.

Posted December 27, 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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Stromberg-Carlson Nos. 230 and 231 SeriesRadio Service Data Sheet November 1937 Radio-Craft

Stromberg-Carlson Nos. 230 and 231 Series

Stromberg-Carlson Nos. 230 and 231 Series
Radio Service Data Sheet
November 1937 Radio-Craft