Restoring the Philco PT- 44 Antique Radio
capacitors is not critical, but do try to get close.
I have found that the values used in the old
radios are still common today. The coupling and
bypass capacitors are typically between 0.001 to
0.2µF. Film capacitors like those in Photo 5 are good
substitutes. I use 600 VDC rated film capacitors for
all my radios. You can purchase these capacitors
from just about any electronics parts distributors.
The Philco radio was one of the more difficult
radios to service. It has a compact design for a set
of this era. The set is so compact that the engineers
mounted the second IF transformer on the underside of the chassis. This made replacing the components a challenge. The wire insulation used in this
radio was problematic. The insulation had deteriorated resulting in exposed conductors in several
locations. This problem only got worse as I poked
around the chassis replacing the capacitors. In the
end, I had to replace three short wire runs. ■ PHOTO 4. The original state
As a side note, do not replace the mica or of the chassis wiring before
ceramic capacitors. These capacitors are stable modifications. The capacitors are recognized as the large, brownish ■ PHOTO 5. After the electrolytic
and rarely ever go bad. You should leave the yellowcomponents. This radio capacitors have been relocated
can type electrolytic capacitors in place, but was repaired sometime in the past (lower part of the picture). The bright
electrically disconnected. as evident by the non-original yellow components are the metal film
I have performed this simple capacitor replace- “Olson” brand capacitor. coupling and bypass capacitors.
ment surgery on dozens of radios. It has restored
95% of the radios to full operation. For the remaining 5%, the
work was limited to the destroyed components outlined in
Figure 1, dial cord replacement, and cleaning of the volume controls. I have only replaced a few tubes. It’s actually quite amazing that the old tubes continue to operate as well as they do.
If you have a radio that is difficult to fix, you can find
books at your local library. Antique Electronic Supply
( www.tubesandmore.com) is an excellent source of tubes,
electrical components, and many cosmetic components.
They also sell reprints of radio schematics. The Internet is a
good source of information. If you look hard enough, you
may be able to find your radio’s schematic. Radio clubs are
another resource for assistance in repairing your radio set.
The decision to strip and refinish this radio was an easy
one. The Philco PT- 44 had suffered water damage and had
lost over 50% of its original finish. The parting laminations
had left additional gaps. Luckily, the radio had a simple
design and used good quality veneer. This radio did not
have a decal or any other feature that would be lost if the
set was stripped. The bottom of the set was left untouched,
thereby preserving the paper tube diagram and model
number identification tag.
The first part of the physical restoration is performed
during the electrical restoration. I used water and isopropyl
alcohol to clean the Philco chassis while it was out of the
cabinet. Q-tips and a toothbrush are the cleaning instruments of choice. The tubes were cleaned with a damp
cloth. It is desirable to keep the original printing on the tube
envelopes so be extremely gentle when cleaning tubes.
The wooden cabinet was cleaned with a brush, then a
damp cloth. The loose laminations were then glued back into
position using wood glue. Clamping the lamination on this
curvy cabinet required ingenuity. A “C” clamp and many
heavy books were enlisted in the process. The plastic dial
covering was removed along with the cloth speaker cover.
The chemicals to refinish the wood cabinet were
purchased at a home supply store. The radio was stripped
using KLEAN-STRIP’s Klean Kutter Refinisher (www.klean
strip.com). This is a mild chemical that removed the old
finish as advertised. I used a cheap paint brush and a
scouring pad to apply/remove the stripper. Most of the
original stain remained. The radio was sanded using 200 grit
sanding paper to remove all traces of the original finish, as
seen in Photo 6. The radio was stained using MINWAX’s
Early American 230. A soft rag was used to apply the stain.
Finally, the radio was finished using three coats of DEFT’s
Clear Wood nitrocellulose Brushing Lacquer. A good quality
paintbrush was used to apply the finish. The cabinet was
buffed with #0000 steel wool between applications.
There is one final point I want to make concerning the
Philco PT- 44. This radio could be considered hazardous
waste due to its asbestos content! As I’ve mentioned several times, this radio is one of the more compact wooden
radios you will find. The designers of this set must have been
concerned about overheating because they installed what
looks like an asbestos liner underneath the chassis. I have
chosen to leave the pad intact. Asbestos isn’t a problem if
November 2006 39