|-------> Vintage Radio Restoration <------------------ Vacuum Tube Technology
(Restoration of a 1930s Vintage Table Top Radio (my great uncle Wills' old radio - photos and tips). I have also
started some pages concerning tube radio restoration and information for radios from the 1950s and early 60s.
NOTE: SOME VINTAGE RADIOS from the 60s and 70s use solid state components. In the late 1960s..most radios
were solid state and some ham radios used both transistors and tubes. These are called "hybrids". Tubes are still
favoured by some..as having nice audio characteristics (rich tones) that seemingly cannot be easily produced with
solid state components.
The first task is to clean it up. It has been sitting in storage and not
used to my knowledge since about 1980. I did try it and it worked for a
few seconds but died. Now I have to clean it up and re-cap it and test
the tubes ect.
The Capacitors that will be replaced first are those light
colored tubular wax coated paper capacitors. They are
generally bad news. In the photo I have marked these
capacitors with a red X. What I will do is snip them out one
at a time (leaving the leads connected in the circuit). I will
then determine the voltage rating and the capacitance and
polarity. A black band at the end indicates the polarity. To
tell you the truth; its been a while since I was working with
capacitors and I'm not even sure at this moment what the
band actually indicates. I will have to hit the text book to
make sure. Anyways..I will replace these capacitors with
modern epoxy plastic ones.
If you look closely at the picture between the two Xs on the
right hand side, there is a smaller rectangular MICA
capacitor. Usually ..these MICA capacitors and disc
ceramic capacitors aren't too bad and can be left in the
circuit. In the middle left side of the photo is an old style
brown colored resistor with a green end and an orange dot
in the middle. This component is "probably OK" and I'm
going to leave it alone for now. These old carbon resistors
can change value a bit because they soak up some
moisture from the air..but after the radio is working, they
dry out a bit and don't usually cause too much difficulty.
Lots of Q tips are generally used when cleaning the chassis.
The large 3 gang variable tuning capacitor was cleaned by
spraying it with electronic contact cleaner. I used a bit of
gas line antifreeze (alcohol) on the chassis and the tube
shields ect. to clean off crud. For the electronic components
themselves you can buy 99% pure alcohol at the drug store.
After many years the insulation on the wires gets a bit brittle.
If you look at the picture below of the two shielded tubes, the
insulated wire runs from the top of the tube (the plate cap) to
the variable capacitor. There is a risk of a short between the
wire where it exits the tube shield. The tube shield is at
ground potential and there may be a substantial voltage of
+ 400 volts on the plate cap and in this wire. I plan to add a
length of insulated tubing to augment the insulation on the
wire so as to prevent possible shorts.
I will provide more photos later. NOTE: HAZARDOUS
VOLTAGES EXIST IN THESE OLD TUBE RADIOS. THEY CAN
GIVE YOU A SERIOUS LIFTER OR EVEN KILL YOU. MAKE
SURE THE SET IS UNPLUGGED. YOU CAN BLEED OFF
DANGEROUS VOLTAGES THAT MAY BE STORED IN SOME
OF THE LARGER CAPACITORS BY USING A 1 MEGOHM
RESISTOR (WITH A CLIP LEAD) TO SHORT TO GROUND.
IF YOU LOOK AT THE UPPER RIGHT HAND CORNER OF THE
PHOTO you will see a large cylindrical vertically mounted
capacitor. This is a filter capacitor for the power supply to power
the circuitry. They do go bad with time. They can develop leaky
conditions and resistive losses. They look in pretty good
condition in this radio and I may leave them alone initially and try
operating the radio with these original capacitors.
If I choose to replace them..I may end up taking the GUTs out of
the enclosure can and replacing the GUTS with a modern
Electrolytic capacitor. NOWADAYS the modern Electrolytic
Capacitors are smaller and can fit in the old enclosure. This
method preserves the "old look" of the unit...but allows an
upgrade in the circuitry at the same time.
CLICK HERE TO GO TO PAGE 2
OF THIS RESTORATION
to go back to my INDEX PAGE (start page) CLICK HERE
Out with the OLD and in with the NEW....
Capacitors that is. The old paper capacitors
(wax impregnated) were removed (snipped out)
and spliced in to the circuit were these newer
epoxy or plastic coated capacitors.
The old capacitor was .05 micro-farad at
200volts. The new plastic one was .05 at 600
volts. 600 volts is a better voltage rating and it
means that the capacitor can withstand higher
voltages in the circuit. It would be a little more
rugged (which is good).
The black band is the polarity indicator. The
new capacitor I used did not have a polarity
indication on it. The black band indicates the
negative end of the capacitor. The negative
ends usually go to ground. The ones I replaced
today were oriented in that manner.
The old capacitors on the right were removed from the circuitry. Most were
.05 uf values. One of them was .0.1 uf (at the top). It will be replaced by a
0.1 uf ORANGE DROP capacitor. Note there is a polarity indicator on the
orange drop capacitor. (The banded end).
I will be looking for more 0.1 uf and 0.05 uf epoxy capacitors this spring when
I go to the HAM RADIO FLEA MARKETS.
I usually go to the Ottawa and Smiths Falls Ham Radio Flea Markets and I
often set up a table there. Look me up if you are in the area.
Above: my Uncle Wills old Sears Silver tone. Covers 550 khz up to 18 MHZ in 3
Typical condition of an old radio: (missing knobs), scratched wood case, Glass
cover for tuning dial was broken ..now missing..and the radio itself has gone
DEAD! I used it a great deal from 1969 to about 1975. Here are some steps in
|This restoration is of an old "tomb-stone style" radio
from the 1930s. I also have a few pages for restoration
of a couple of old radios from the late 1950s.. (a Korting
1031 and a Normande stereo/radio ..CLICK HERE FOR
THESE PAGES of photos and tips on restoring.
I spent many hours in the
late 1960s listening to 75
meter AM phone and the
broadcast band. I used
this radio up until about
It has been sitting idle in
my parents basement up
until about 2005 when I
brought it up here to my
new home in Elliot Lake.
It now does not function.
I have started the
restoration and will
complete it soon (I hope).
Here are some photos of
the steps involved.
These pictures were taken with an old digital camera and so the resolution is not
really up to snuff for 2011.
The blue (robin egg) colored capacitors were from my old stocks I had around
here. The orange one is an orange drop capacitor. I went out and bought a kit of
capacitors for restorations ..from Just Radios (dot com).
I dont have too many extra capacitors in my stocks..but I could help you out with a
few if you need to finish off a restoration. I also have tubes and a tube checker
and I SELL THE ODD PART BY MAIL ORDER. See my parts page which is only a
partial listing. CLICK HERE FOR MY PARTS PAGES.