A list of questions that I am frequently asked, and their answers (to the best of my knowledge):

1.  What are CD marks?
2.  Who made the first transistor radio?
3.  I thought Sony made the first transistor radio?
4.  Where were transistor radios made?
5.  What is "reverse painting"?
6.  How old is my radio?
7.  What is my radio worth?
8.  How can I fix my radio (or have it fixed)?
9.  My radio takes a weird battery.  Where can I get it?
10.  Where did you get all of your radios?
11.  Are any of your radios for sale?
12.  What were the "Transistor Wars"?
13.  What are "Boy's Radios"?
14.  How does a radio work with only two transistors?

1.  What are CD marks?

CD marks appear on most radios sold in the United States during the years 1953 to 1963.  CD, which stands for Civil Defense (some people think it stands for ConelraD, but that is the program itself, not what the markings mean), was taken very seriously in the 50's and 60's as communist hysteria swept the nation, and the Soviet Union obtained first the atomic bomb, and then the hydrogen bomb.  Ballistic missiles weren't really an issue back in those days--the threat was seen to be from waves of bombers attacking US shores.  To counteract that possibility, the US Government enacted the CONELRAD program.  CONELRAD stands for CONtrol of ELectromagnetic RADiation, and was intended to ensure that Russian aircraft wouldn't be able to use our broadcast stations for homing purposes.  CONELRAD established two CD frequencies, 640 and 1240 kilohertz, and during times of declared emergencies, all stations except CONELRAD stations at the designated frequencies would cease operations.  The CONELRAD stations would disseminate information to the (presumably) terrified public, so radios had indicators as to where people should tune their radios.  CONELRAD was obsolete with the advent of ballistic missile technology, and was replaced in 1963 with the Emergency Broadcast System (EBS), which has since been replaced by the Emergency Alert System (EAS).  CD marks are useful for dating radios produced during the CONELRAD era, but there are exceptions.  The Hitachi TH-666, for example, was produced during this era, yet has no CD marks.  The Precor 550 was produced long after the era, yet has the marks.  CD marks serve to distinguish the era when most collectible transistor radios were produced.

Back to top

2.  Who made the first transistor radio?

The first transistor radio was produced by a company called Regency Electronics (originally called I.D.E.A. Corporation).  The company had been approached by Texas Instruments to use TI transistors to build the first commercially-produced transistor radio.  This occurred only after the big players in the field (such as RCA, Emerson, and Philco) declined to take on the project.  Regency was a maker of television antenna boosters at the time.  The company designed a 4-transistor radio and quickly came up with a case for it.  All the components barely fit the case; a screw on the tuning capacitor stuck out far enough that a small "dimple" had to be ground into the back of the case to allow the circuit board to fit.  The radio was introduced in the Fall of 1954 as the Regency TR-1, and initially was offered in four colors:  black, white, red, and gray.  Later, two other colors were added:  jade green and a mottled mahogany.  There were also some pearlescent colors offered at a premium price--today, these are exceptionally rare and valuable.

Back to top

3.  I thought Sony made the first transistor radio?

Sony made the first Japanese transistor radio, but the Regency TR-1 was the first ever.  Sony's first commercially-produced radio, the TR-55, arrived in 1955 and was never distributed in the United States.  These radios are extremely rare today.  Sony's first radio to be distributed in the U.S., the TR-63, arrived in 1957 and saw great success.

Back to top

4.  Where were transistor radios made?

Transistor radios have been produced all over the world.  Produced first by countries with the largest electronic technical pool (the United States, Japan, and several European countries), radios moved on to be items that could be easily manufactured anywhere.  Radio manufacturing locations shifted as competition forced prices down, and labor became the major expense.  After the U.S. and Japan, manufacturing shifted to Hong Kong, outlying islands such as Okinawa and the Ryukus, and then on to Taiwan and Korea, eventually (today) to such places as China and The Philippines.  Most collectible transistor radios were made in the U.S., Japan, and Europe.

Back to top

5.  What is "reverse-painting"?

Reverse-painting is a technique very much favored by the Japanese in their early transistor radios, and resulted in a plethora of beautiful radios which are sought by collectors.  Reverse-painting uses clear plastic as the base.  Generally, any details the manufacturer wanted to place in the clear area, such as dial markings or ornamentation, were incised (cut into) or ground into the plastic, leaving a small indentation.  The indentations were then sprayed or colored with a paint, then the entire back of the clear plastic section was coated with a paint of a different color, or left clear.  This resulted in radios with gorgeous, three-dimensional details.  See the feature article on the Zephyr ZR-930 for a good example of reverse-painting; the entire top of the radio is done in this technique.

Back to top

6.  How old is my radio?

There are a lot of clues to the age of transistor radios.  Primarily, look for CD marks.  If you find these, you can be relatively certain that the radio was produced during the period of 1955-1963.  However, that isn't the only clue, and cannot be relied on exclusively.  Electronics changed considerably over the period of radio manufacture.  Transistors, specifically, look different in older radios, often being of oval shape, or having steel cases which resemble top hats.  Radios which contain black plastic encapsulated transistors are from later, after the mid-1960s.  Cabinets offer a wealth of information, too.  Early cabinets tend to be of thicker, smooth plastics; often formulations which chipped easily.  Although black remained a common color, early transistor radios are often brightly-colored, and use a technique called "reverse-painting" for dials and other pieces.  Early radios are often highly decorative; later radios tend to be very cheaply built, often black, with little highlighting, thin plastic, and pebbly (rough) surfaces.  Finally, also check to see where the radio was made.  If it was made in Japan, the U.S., or Europe, chances are it is an earlier model.

Back to top

7.  What is my radio worth?

A popular question, and a difficult one to answer, as the market for transistor radios is extremely volatile.  I recommend some of the guides on my Recommended Reading page for general valuations.  Ebay (www.ebay.com) has become a primary factor in the pricing of these radios, as they are small and easy to ship.  Monitoring Ebay will quickly give you an idea of what the going rate is for various radios.

Back to top

8.  How can I fix my radio (or have it fixed)?

I don't recommend anyone without training in the use of electrical test equipment or soldering gear attempt work on their own radios.  While battery-powered transistor radios aren't dangerous, if you don't know what you are doing, it is possible to cause more damage.  In addition, older transistor radios use parts not readily available these days.  While newer parts can be substituted in many cases, circuit changes may be necessary, and this can destroy the value of a historically-significant radio.  For example, I'd never replace the transistors in a TR-1 with contemporary units.  That said, most problems in transistor radios tend to be easy fixes.  If the radio is completely dead, suspect either the battery connector (the number one problem, due to flexing and corrosion), the on/off/volume control, the earphone jack (because it cuts off the speaker when the earphone is inserted) and the speaker itself.  If the radio comes on but only hisses, the antenna might be the problem.  Finally, older radios often have excessive leakage of their electrolytic capacitors, and replacing these can greatly improve operation.

I don't know of anyone who works on these as a business for other people.  If you want a radio repaired and do not care about the parts used, a local electronic repair facility may be able to fix it for you.

For those interested, I strongly suggest an out-of-print book called How To Fix Transistor Radios and Printed Circuits.

Back to top

9.  My radio takes a weird battery.  Where can I get it?

Old transistor radios used a wide variety of batteries.  Most are obsolete and difficult to find today.  Many are still available, if expensive.  I'd suggest the Radio Shack battery finder on their web site, and the Eveready Battery Company has nice details and technical information.  Finally, you can often use the standard 9V transistor radio battery (known as BL-006P) in place of the larger 9V batteries used in older radios by simply making a connector adapter.  For radios that used button cells, you can often cobble together new button cells to come up with an appropriate voltage.

Back to top

10.  Where did you get all of your radios?

I have been collecting radios since I was a child, although I didn't get seriously into it until about ten years ago.  In the old days, I used to find plenty of radios at flea markets (or "swap meets", as they were called where I lived).  In outlying areas, flea markets can still be good sources of radios.  I find antique stores located in metropolitan areas to have few radios, and the radios that they do have are usually wildly overpriced.  I occasionally find a reasonably-priced gem at these places, though.  In my area, there are radio flea markets operated by a chapter of the radio collector's association, and transistor radios are often found there (although the emphasis is on tube sets).  These days, however, by far the best place to look for radios is on the Ebay auction site.  Hundreds of transistor radios are listed at any one time, and it is where I pick up perhaps 90% of the radios I purchase anymore.  One has to be cautious, as you don't generally know the sellers when you first start out, and you can't inspect the radio except via photographs, but I have been generally pleased with what I have obtained.  Watch out for sellers with a significant amount of negative feedback.

Back to top

11.  Are any of your radios for sale?

I had intended on keeping my collection forever, but space requirements dictated that I had to sell the collection. I no longer own the radios pictured on this site.

Back to top

12.  What were the "Transistor Wars"?

In the early 1960s, transistor prices had come down enough that certain manufacturers began to increase the count of the transistors in their radios, ostensibly to offer better performance.  However, in most AM-only radios, only eight transistors actually are active in the circuit.  The extra transistors were merely soldered into the board and didn't do anything!  (In fact, some manufacturers used "dud" transistors.)  The one-upmanship rose to ridiculous levels, with transistor counts of 16, 18, or even higher being claimed.  The practice finally died out when the term "solid state" became popular for any tubeless radio.

Back to top

13.  What are "Boy's Radios"?

Certain radios will have the label "Boy's radio" on them.  Tariffs on Japanese radios were higher than those for Japanese toys.  US tariff law did not define a radio containing two transistors or less as a radio; instead, it was defined as a toy.  Japan took advantage of this by producing countless variations of radios containing two transistors or less.  The performance of these radios was usually quite marginal, but they sold well anyway due to their low prices.  Most weren't aimed at children, although some were.  Check out a brochure for the Coronet radio, which is extremely common.  Nowhere is it mentioned that this is a two-transistor circuit!

Back to top

14.  How does a radio work with only two transistors?

Most boy's radios don't have schematics in them.  However, my friend Ronald Rissel went to the trouble of tracing out the circuitry of a Sovereign radio and produced a schematic.  You can see the schematic and read Ron's description of the circuit.  My thanks to Ron for doing this!

Back to top

Copyright © 2006 by Sarah Lowrey.  All rights reserved.