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Hetro Air-Ace Series M, 9-Tube 4-Band Superhet
Radio Service Data Sheet
May 1936 Radio-Craft

May 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.

This is another Radio Service Data Sheet which appeared in the May 1936 edition of Radio-Craft magazine. I post this schematic and functional description of the Hetro Air-Ace Series M, 9-Tube 4-Band Superhet manufacturers' publications for the benefit of hobbyists and archivists who might be searching for such information either in a effort to restore a radio to working condition, or to collect archival information. A thorough search on the Internet turned up no examples of a surviving instance of the Hetro Air-Ace Series M radio. BTW, the "Air Ace" part of the name refers to the radio air, as in "on the air" or "over the air," not a fighter pilot ace with a certain number of kills painted on the side of his airplane.

Hetro Air-Ace Series M, 9-Tube 4-Band Superhet

(Range, 140 kc, to 20 mc.; metal tubes; 6B5 output tubes; 1 iron core I.F.T.)

Voltages, as measured with a 1,000 ohms-per-volt meter, are as follows:

*Grid 2, 145 V. All readings taken to ground. About 125 V. drop in speaker field. Power output is 15 W.

Band switch allows phono. operation when in extreme left position: Note that I.F.T.1 is of the iron-core type. Use a series resistance of 400 ohms when aligning bands 1 and 2, and a condenser of 250 mmf. for other bands. Alignment frequencies are 18 and 9 mc. on band 1, 6 and 2 mc, on band 2, 1,500 and 600 kc. on band 3, and 350 and 150 kc. on band 4. The I.F. amplifier is aligned with a series condenser of 250 mmf: between the service oscillator and the control grid of V2, I.F.T.1 is the last transformer to be lined up. A ground connection should always be used between service oscillator and set.

Posted March 28, 2023
(updated from original post on 5/18/2015)

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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Hetro Air-Ace Series M, 9-Tube 4-Band SuperhetRadio Service Data Sheet May 1936 Radio-Craft

Hetro Air-Ace Series M, 9-Tube 4-Band Superhet
Radio Service Data Sheet
May 1936 Radio-Craft