Take a look at Photo 2.
There are a few approaches you
can take while going through
component replacement. Some
people argue it's best to replace only
the electrolytic capacitors in the
power supply, then one capacitor at
a time powering up in between each.
This takes quite a while, and with all
the other components still original, is
pretty risky. I'd personally never
recommend such a practice for a
radio from the early years, although
with something manufactured in the
late '50s and into the '60s, you might
be able to get away with it.
It looks like someone already
tried that approach on a radio a few
years ago. Check out Photo 3. There
are two modern electrolytic and one
film capacitor, but the rest are 1930s-
I like to proceed carefully, one
component at a time until all
questionable capacitors have been
replaced, then power it up and see
what happens. By replacing each
component one at a time and only
lifting one lead at a time, it's easy to
make sure you don't mis-wire
Connecting a film capacitor to
the wrong place in the circuit won't
generally cause anything to burn out
(since capacitors block DC current),
but can cause the radio not to play,
for example, by shunting the radio
signal to ground before it gets to the
next tube. Just be careful not to
connect an electrolytic capacitor
June 2015 49
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Photo 3. Underside of the chassis.
Mostly '30s and early '40s capacitors,
with some early 2000 era replacement
parts thrown in.
Photo 1. Top-down view of the De Wald 618 chassis.