Description
This article is from the Antique Radios
And Phonographs FAQ, by Hank van Cleef vancleef@netcom with
numerous contributions by others.
36 I just got an old radio at a yard sale for $5. It is a Radio WireTelevision Model J5. When was this radio built? Can I get it towork? Is this radio worth restoring? Can I get a schematicsomewhere.
Requests like this send everyone scrambling for their references,
schematics manuals, etc. etc., and sometimes nobody responds. There is
some very basic information that you could, and should, include, that
would get you an answer instantly. If you included "this radio uses
five tubes. They are 12SA7, 12SK7, 12SQ7, 50L6, and 35Z5." See below
on "how to date radios by design features." Listing the tubes often
says everything.
The example used here is one of an endless long list of AC-DC table
radios built after 1940 using this tube complement. This type of set
is known as an "All-American Five." Most people who repaired radios
in the forties and fifties could draw the schematic for any of these
radios from memory----it's a case of "seen one, seen 'em all." This
particular radio has a grand total of 9 resistors (including volume
control), a whopping 14 condensers (including the tuning condenser as
one), three transformers, one oscillator coil, a loop antenna, a
loudspeaker, and a panel lamp. Add the five tubes, and that amounts to
the whopping sum total of 35 electrical components, and if you want to
insist on including the chassis, five tube sockets, cabinet, panel lamp
socket, and cabinet, we are still talking about 50 parts. No wonder
they sold for $4.98 in 1940. If it has value, it is for its case and
mechanical configuration. As a project radio to learn radio repair
and restoration, an AC-DC 5 or 6 tube table set is probably ideal. Most
of these sets need one tube (burned-out heater), new electrolytics and
paper capacitors to get it "working like new."
Typical schematics for All-American Five radios are given in the RCA RC
series and GE Receiving Tube manuals available in reprint from Antique
Electronic Supply. Actual production radios of this design had a
variety of subtle variations, but the typical circuits in the tube
manuals should help you find your way around one of these sets.
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