How can I fix my old radio?
Hardly a week goes by without somebody sending me a message like this:
Help, Phil! I just bought a Schmidlap 357 and it looks really great.
But when I turn it on, it just makes a loud buzz (or doesn't make a sound, etc.)
What should I do???
If you're in this position, here are some answers to help you get started.
Should I fix it myself, or hire someone to do it?
You don't need advanced electronics knowledge to fix most old radios.
Tube-powered radios are simple in comparison to modern electronics.
Most were built to conventional designs, and they use replacement parts that
are still readily available. Fixing
old radios can be an enjoyable hobby in itself, and you might even learn
something about one of our century's key technologies.
On the other hand, working on any electrical equipment can pose a danger
of serious electric shock. And botched repairs can make a problem worse,
if you're not careful. If you've never done such work, and you're not
interested in learning how, it's best not to try poking around blindly.
Where can I find someone to fix my radio?
You might find someone simply by checking in the Yellow Pages or phoning
local electronics repair shops. You can also try contacting
the nearest radio/TV collector club for a recommendation.
Naturally, it's preferable to find someone within driving distance, to avoid the cost
and risk of shipping your item long distances.
The Antique Radio Classified website
has a list of clubs
throughout the world. The print version of ARC magazine also carries ads
for repair shops and other services; you can get a free sample copy of
ARC magazine upon request. Finally, if you search for a phrase such as
"vintage radio repair" on a service such as Google or Bing,
you can find repair shops that advertise on the Internet, although these
may be located far from where you live.
Is there a book that I can read?
Yes! Some excellent radio-repair books are listed on
my page Books for Radio Collectors.
Your public library may have these, or they can be ordered from
Antique Radio Classified,
amazon.com, or your local
Many other out-of-print repair books can be found through
used-book sources, including eBay.
If you get a good repair book, you can
basically skip the rest of this page. The book will cover the
same ground in more detail.
Are parts still available?
Yes. Commonly needed electronic components are readily available.
See my Parts page.
What skills do I need?
For the most common repairs, you need to be able to read and to do simple
soldering. SAFETY WARNING: You also need to know how to work
safely around electricity. Old radios carry high-voltage current that
can cause injury or death. The repair books explain how to do this work
safely. Never stick your hands (or anything else) inside an old radio
if you don't know what you're doing.
Do I need to get a schematic diagram before I start?
It's a good idea for beginners. Radios can be repaired using the general
techniques and information given in repair books. Many
problems require specific information, however, and the schematic
may include other useful facts, such as the date of manufacture.
Schematics for US and Canadian radios typically cost a few dollars and can be
obtained from the sources in my Parts page. You can
obtain many free schematics by downloading from
Nostalgia Air or
visiting the reference desk at a decent-sized public library.
Do I need to replace all of the tubes?
No! A common misconception about radio repair is that you should
start by replacing tubes. Like a light bulb, a radio tube is vacuum-sealed and doesn't
deteriorate from simply sitting around. You don't need to replace
a tube unless you have some evidence that it has failed. Other components,
such as capacitors, are more common causes of trouble than tubes.
What tools and equipment do I need?
The one tool you can't do without is a small, pencil-type soldering iron, available
at stores such as Radio Shack. You may already have the other gear you'll need—a
couple of screwdrivers (Phillips and normal head) in different sizes, a small
adjustable wrench, pliers (regular and needle nose), wire cutter,
and a small knife for stripping insulation from wire.
The most useful piece of equipment is
a multi-tester, a small device that measures voltage and resistance.
You can get one for around $25 at Radio Shack and many other sources.
If you do frequent repair work, the next most useful item is
a signal generator, a device that can generate audio and RF (radio
frequency) signals at various frequencies. By injecting a known signal
into various stages of the radio's circuit, you can zero in on the source
of a problem. For instance, if you inject an audio signal into
the audio output stage and no sound comes out of the speaker, you know there's
a problem in that part of the radio. A signal generator is also
essential for aligning the radio, although that procedure
is often not necessary.
Many people ask me whether they'll need a tube tester. The answer is no,
for a beginner. Tubes are pretty reliable, in the first place, and
there are other ways to test them. Use an ohmmeter to test for
continuity between the tube's filament (heater) pins. If the
ohmmeter shows infinite resistance, the filament is broken and
the tube is a dud. If it shows a small resistance, the tube
should light up. (Tube pin diagrams can be found at
Nostalgia Air and
similar websites.) You can also substitute a known-good tube in
place of a suspect tube, to see if the radio plays better.
Conversely, you can put a suspect tube into a radio that already
works, to see if the performance changes.
The same is true of other equipment such as oscilloscopes. If you have one, it can
be handy on occasion, but if you don't, there's often another way to skin the cat.
It's amazing what a skilled repair person can do just by
looking, listening, substituting components, and making
measurements with the multi-tester.
How can I refinish the cabinet?
Refinishing wooden radio cabinets is no different than refinishing other wooden
objects. My favorite book on wood refinishing is
The Weekend Refinisher by Bruce Johnson. For more details, see
Books for Radio Collectors.
website's Restoration section
also provides specific information about refinishing various
types of cabinets.
My preference, which is shared by most collectors, is to restore wooden objects
without making them look "brand new" or erasing all evidence of age and use.
If you strip or sand a radio cabinet down to bare wood, you may destroy its
collectible value, along with its character. The same goes for applying non-authentic
finishes, such as glossy polyurethane. The Weekend Refinisher explains
how to detect what finish is on a piece and restore it authentically.
Restoring bakelite or plastic cabinets is mostly a matter of cleaning and
polishing. I recommend starting with the gentlest possible means and
materials, and resorting to stronger methods only if necessary. I always
start out with warm, soapy water, some clean, soft cloths, and a soft
toothbrush for the small crannies. Cotton Q-tips and round toothpicks also
come in handy for tight spots. Avoid solvents, especially when working
with an unknown modern plastic. Nothing is more disheartening than
watching your newfound treasure start to dissolve under your fingertips!
The strongest cleaner that I use for cleaning stubborn grime is window
cleaner such as Windex.
For cabinet polishing, I prefer Novus Plastic
Polish, grades #1 and #2, available from Antique Electronic Supply.
Novus polish is gentle enough to safely polish the most delicate plastic dial covers, yet the #2 grade
does a fine job on faded old bakelite, too. Other collectors polish with various substances,
such as very fine-grade automotive rubbing compound, power buffing wheels, and so on.
Some collectors wax bakelite cabinets after polishing, but I've not found that
worth the bother, if you've done a good job of polishing. Be patient,
and stick to soft cloths and elbow grease.
Cracks in Bakelite and plastic cabinets be reglued with cyanoacrylate ("crazy glue") if the break is clean.
Larger defects in a plastic cabinet can be patched with a product
called "Plas-T-Pair," available from Antique
Electronic Supply. Larger breaks in a Bakelite cabinet may
be harder to repair, although I have heard of people patching them
with a mixture of ground Bakelite and some sort of glue.
What's the best way to learn?
The best learning method is probably to watch over the shoulder of an experienced
repairman at work. If you join a local collector's club, perhaps you can find
someone willing to give you some pointers.
Our Restoration section contains many articles on restoring specific radios, including tabletop, console,
cathedral, and tombstone models, as well as communication receivers.
These articles contain all sorts of tips and practical advice about
repairing electronics and refinishing cabinets.
A good book on radio repair is invaluable. As mentioned earlier,
our books page has several to recommend.
If you're a complete novice in electronics, I recommend practicing on a
junky radio before you tear into
your treasured antique. A visit to the local thrift store may
provide a suitable tube-powered patient for only a few dollars.
It won't be exactly like your "real" radio, but the techniques that you learn
will be generally applicable.
Practicing on a junker will help you learn whether you like this activity,
and you can make those inevitable beginner's mistakes on a set that
doesn't have great emotional or monetary value.