May 1931 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.
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. A Google search for a photo or advertisement of the Silvertone "F" and
others in this series did not turn up anything. If you have one, please let me know where to find
it. There are 187 Radio Service Data Sheets as of May 2, 2017.
Silvertone "F," "FF," "G," "H," and "J" Radio Service Data Sheet
The Silvertone, it will be remembered, is the trade name of
a line of radio receivers sold by Sears, Roebuck & Co., Chicago, Ill. The "Model FF" and "J" are
two of the older sets dating back to 1926, which were manufactured for this company by King Mfg. Co.,
Buffalo, N. Y.
These two complete diagrams, shown below, have been selected as representative of the circuits followed
in the following models: "F," "FF," "G," "H," "J." A few words will serve to distinguish them:'
The "Model F" Silvertone radio set is a 5-tube receiver using four '01A's and a power rube which
is either a '12A or a '71A. It is a battery set of the neutrodyne type, with single control. The grid
condenser has a value of .00015-mf.; and the grid leak of 3 megs. The detector plate by-pass capacity
is .006·mf. The detector grid leak does not shunt the grid condenser, but returns directly to the positive
side of the detector filament; and between this point and the "A" supply lead is a 2-ohm resistor. This
detector filament lead and the positive filament leads of the two audio tubes connect to a 1-ohm resistor;
which is also wired to the "A+" post, as well as a 10-ohm rheostat to complete the positive "A" circuit
of the two R.F. tubes. This rheostat is the volume control. The off-on switch is in the "A-" lead, which
is grounded. The R.F. tube circuits are designed to operate at 90 volts on the plate. The first and
the second audio stages have independent "B" and "C" supply leads. The reproducer connects directly
in the plate circuit of the last tube.
Posted May 2, 2017