Zenith Royal 500 Transistor Radio (1956)

  

Very popular among collectors, this is Zenith's very first transistor radio. The case measures 5 3/4 by 3 1/2 inches and is made of black "unbreakable nylon" trimmed in gold. The Zenith crown logo appears between the round controls.

If you're trying to date one of these radios, look at the knobs. The earliest models have a bar across the round knobs, as shown here. Later models have round knobs without the bars.

This model is notable for its hand-wired chassis, unlike later solid-state radios that use printed circuits. If you look at the chassis view, you can clearly see the hand-soldered connections.

Seven transistors are used, as follows:

Transistor Type Function
1 2N194 Mixer
2 2N193 Oscillator
3 2N216 1st IF amplifier
4 2N216 2nd IF amplifier
5 2N35 Driver
6 2N35 Output
7 2N35 Output

The hand-wired transistor set occupies an interesting place in the history of radio technology. With its miniaturized components and modest power requirements, it paved the way for true "go anywhere" radios. Yet the hand wiring is reminiscent of earlier tube radios. Along with transistors, printed circuits became commercially feasible during the 1950s, another important step toward making electronic devices smaller and cheaper.

It's interesting to compare this radio to my Emerson 888 Pioneer. The eight-transistor Emerson uses a printed circuit, but it is larger in every dimension and heavier than the Royal 500. Both sets have a nylon cabinet and are powered with four AA dry cells.

Printed circuits were used in 1950s tube radios as well as transistors. Motorola used the term "plated circuit" to describe the chassis in my Motorola 5P21N tube portable. Printed circuits were also found in tabletop radios, such as my RCA 1-X-4EJ and Westinghouse H-742T4. Another chassis varation of the 1950s was the folded metal chassis, found in my Westinghouse H-417TS and others.

This radio is in good original condition. Right now, it emits some background hiss but does not receive any stations. I haven't poked around to see what the trouble might be. I know there's a transistor tester buried somewhere in my shop. Perhaps it's time to dig it out!

I don't look for transistor radios very often, but this one has some historical interest and it is very attractive. A fellow collector ran across it in a local thrift store and passed it along to me at a very reasonable price. (His interest is boatanchors, not transistors.) Thanks, Bill—and if you run across any other good deals, let me know!

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