RCA-Victor "Magic Brain" Model 281, All-Wave Superhet
Radio Service Data Sheet
August 1935 Radio-Craft

August 1935 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.

This Radio Service Data Sheet which appeared in a 1935 issue of Radio-Craft provides schematics and parts lists for RCA-Victor "Magic Brain" Model 281, 12-Tube All-Wave Superheterodyne receivers. Most - if not all - electronics servicemen had subscriptions to these magazines because they were a ready source of not just these service sheets, but because of the extensive articles offering advice on servicing radios and televisions. In fact, many electronics manufacturers had a policy of supplying service data only to bona fide shops. A large list is included at the bottom of the page of similar documents from vintage receiver schematics, troubleshooting tips, and alignment procedures.

RCA-Victor "Magic Brain" Model 281 12-Tube All-Wave Superhet Radio Service Data Sheet

Output of set is 8 W. (undistorted; 16 W., max.) into special 10 in. reproducer. Aligning frequencies in kc.: 175, 410, 460, 600, 1,720, 5,160 and 18,000. Power consumption of set 130 W.; frequency range 111 kc. by bands X-140-410; A-540-1,720; B-1,720-5,400; C-5,400-18,000; D-18,000-36,000. Two A.V.C. units compensate receiving conditions in different bands; high- and low-frequency controls compensate station hum, static, etc. Operating voltage and current figures follow. *Osc. cath., 3 V. and 10.9 ma., Plate 232 V. **768/384, r.m.s. All voltages measured to ground; P.T. connected to 120 V. tap; line, maximum sensitivity; no signal.

Posted April 26, 2024

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 255 Radio Service Data Sheets as of April 30, 2025.

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 tying up your telephone line, and a lady's voice announced "You've Got Mail" when a new message arrived...