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 don't usually read through all of the text included
with these Radio Service Data Sheets, but I did see at the end of this one where instructions are given
for increasing the sensitivity of the units. Capacitor value increases are made in the
dynatron oscillator
circuit, which is the beat frequency oscillator (BFO) in the received signal path. Why wouldn't that
have been incorporated in the factory-built radio? My guess is that the tuning process would take more
effort than a typical owner would be willing to tolerate. I could not locate a photo of the Model 826B.
Kennedy "Model 826B" Combination Receiver
With the "Model 826B" broadcast receiver , the Colin B. Kennedy Co., South Bend, Ind., pioneers the
field of mass-produced "combination-wave" radio receivers The long-wave chassis, covering the regular
broadcast band (and a bit more), tunes from about 195 to 550 meters, and is "Model 26;" the short-wave
chassis, "Model 34," tunes over three wave-length bands of 15-25, 25-50 and 50-100 meters, each band
being switch-selected. The two chasses, in a Model 826 cabinet, comprise the Kennedy "Model 82613" receiver;
the latest diagram of connections appears below. The receiver has a tone-control (R8-CI7).
The following modifications for increasing the sensitivity of the "Model 826B" receiver are recommended
only to the experienced Service Man, and are to be applied with care: Change C13S to .04-mf., and shunt
the old 0.25-mf. unit across C14S. Replace C22 by a .002-mf. unit. The shielding of the oscillator output
wire must be grounded to the chassis. A good ground connection must be used for the combination set.
Tube variations will be more evident in a set of this nature and, for best results, it is ad-visable
to try several of each type.
All shielding must be fastened tightly The shielded coil at the rear center of the base is L2S; midget
condenser C2S is on its shield top.
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.
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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