Clarion De Luxe Models AC-280 and 25-280, 12-Tube Superheterodyne
Radio Service Data Sheet
September 1932 Radio-Craft

September 1932 Radio-Craft

September 1932 Radio Craft Cover - RF Cafe[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.

For many years now I have been scanning and posting Radio Service Data Sheets like this one featuring the Clarion De Luxe Models AC-280 and 25-280, 12-tube superheterodyne radio receiver. 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. Unfortunately, an extensive Internet search did not turn up any examples of the Clarion Model 280.

Clarion De Luxe Models AC-280 and 25-280 12-Tube Superheterodyne

One of the newest of Transformer Cor-poration of America's "Clarion" line of radio sets is the De Luxe Model 280 superheterodyne, listing for less than seventy dollars, which incorporates a number of interesting circuit variations with which the Service Man must acquaint himself; these new circuit "kinks" are evident by reference to the schematic circuit.

The component characteristics are as follows: Resistor R1, manual volume control, 0.75¬∑meg.; R2, tone control, 0.1-meg.; R3, 500 ohms; R4, R8, 10,000 ohms; R5, 0.1-meg. ; R6 1. meg.; R7, ¼ meg.; R9, 8,100 ohms: R10, 1,000 ohms; R11, 300 ohms. The field coils measure 400 ohms each; choke Ch., 400 ohms.

In the second-detector stage two type '27 tubes are used in double diode con-nection. In this circuit the detectors are used as ordinary two-element rectifiers of the R.F. signal fed to their control-grids, which arc connected in push-pull. The plates are connected in parallel, the audio component dividing into two paths.

Automatic volume control is secured through the pulsating D. C. (rectified R.F.) drop across R7. The higher powered stations with strong R.F. carriers when tuned in cause greater pulsating D.C. to flow from the detectors' plate-cathode, through R7, to ground; thus, the drop across R7 is in-creased.

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.