May 1936 Radio-Craft[Table of Contents]
People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Radio-Craft was published from 1929 through 1953. All copyrights are hereby acknowledged. See all articles from Radio-Craft.
This is another Radio Service Data Sheet that 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.
(Range, 140 kc, to 20 mc.; metal tubes; 6B5 output tubes; 1 iron core I.F.T.)
Voltages, as measured with a 1,000 ohmsper-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.
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.
Posted May 18, 2015