74 Nice old fifteen tube radio problems with insulation falling of the wiring
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This article is from the Antique Radios And Phonographs FAQ, by Hank van Cleef vancleef@netcom with numerous contributions by others.
74 Nice old fifteen tube radio problems with insulation falling of the wiring
I have a nice old fifteen tube radio. It's got problems with
insulation falling of the wiring, and a couple of repairs that were
badly done. There is a lot of dirt in the coil boxes and bandswitch,
and I can't get at them to clean them up. All of the paper capacitors I
checked were leaking electrically, and several resistors have drifted
way out of tolerance. What can I do with this set to get it working
properly?
There is a point where the best thing to do with an old radio is to
take the thing completely apart, clean up everything, and build it up as
a new radio. While this may seem like a lot of work, it actually is
easier than a major piecemeal restoration. For one thing, taking major
components off the chassis will open up areas and make the rest of the
set easier to work on. You will need an accurate schematic for the set,
and you will need to make copious notes as you take it apart. Note how
the bandswitch and other tap switches are wired, and identify the
connections on the schematic. Make notes on what components are where,
the hardware used to mount them. You will want a bunch of containers,
typically one for each type, to keep parts in. Mark the
containers---don't rely on memory for anything. Your notes are going to
be "kit building instructions" for putting it back together. Clean off
all the old solder to make it easy to install components.
The results can be little short of astounding. You can start with a dog
that has parasitics, won't align properly, and has been butchered by
hackers who fixed everything except what was wrong, and end up with a
brand new radio with superb performance. Work? Yes. But take it one
tube circuit at a time, one subassembly at a time, etc., and you'll be
surprised and pleased with the results.
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