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1. Transistor radios 1950s serial number#
2. Transistor radios 1950s driver#
3. Transistor radios 1950s series#

I located some tiny electrolytics and mounted them on the back of the board ( Figure 8) - they are not visible when the unit is assembled. I couldn’t drill out the units without destroying the sleeve, so I went to plan B.įIGURE 7.

Transistor radios 1950s serial number#

Later units (starting around serial number 20,000) alternated between cardboard and ceramic sleeves.įigure 7 shows the two types. It was important to keep the cardboard-sleeved capacitors, as all the early units used that type. My first attempt was to drill out the tubular units and slip a modern capacitor in the cardboard sleeve. Of the four electrolytic capacitors, three were open and one was shorted. I then replaced the bad output transformer. I chose the best transistors and set them aside.

When I tested them, all the transistors showed a huge amount of reverse leakage compared to later transistors. I have read that the coding was primarily to show junction capacitance, so, the better units could be used in the converter and IF stages, and the higher capacitance transistors in the less critical audio stage. Other than the color codes, the germanium transistors had no part numbers, just a Texas Instruments logo on the side made with a rubber stamp ( Figure 6). I noted color codes on all the transistors and pulled them for testing.

After watching auction sites for a few months, I bought one unit with a badly broken case, and also a bare chassis with a few missing parts ( Figure 5). Obviously, a “parts” unit was needed to proceed. What I found (in addition to that) was one shorted transistor and an open primary on the output transformer. I expected all four electrolytic capacitors to be open or shorted. My unit - perhaps one of the oldest transistor radios in the world (based on the low 2076 serial number) - required careful handling. None are really expected to operate, only to ‘show’ in collections. A rare pearlescent blue unit sold in 2000 for $3,200. A schematic of the TR-1 is shown in Figure 3 with the four electrolytic capacitors highlighted (more on this later) the chassis of my unit is shown in Figure 4.Ī Regency TR-1 in average condition usually sells for several hundred dollars on auction sites. I decided to restore it just so I could hear how it sounded. Like most of the TR-1 parts, it was probably the smallest speaker Jensen made at the time. The speaker in the TR-1 was a 2.75” Jensen - larger than most of the ‘60s pocket radios - so it might sound okay.

Transistor radios 1950s driver#

The 1954 TR-1 had only four transistors with a single audio stage driving the speaker, while the later six-transistor units invariably had an audio amp stage following the volume control and feeding push-pull outputs through a driver transformer. Starting around 1960, the market was flooded with six-transistor pocket radios - with many of those made for American companies. The question really was never answered because the actual production serial number on the commemorative TR-1 they found was not revealed.Īfter having the radio featured on the program, I started to wonder what it actually sounded like 62 years ago. The question for the ‘detectives’ was whether this was the oldest transistor radio in existence.

Transistor radios 1950s series#

The radio I’m restoring in this article ( Figure 2) was featured on an episode of the PBS series “History Detectives.” There are a number of good websites to learn the history of the TR-1, and one of the most complete is The site is run by Don Pies, the son of Regency co-founder John Pies. Early advertisement for the TR-1.ĭespite its high price, Regency sold the first run of about 100,400 TR-1s before introducing the TR-1G (which was re-designed with a PNP output transistor) in 1956. An early advertisement is shown in Figure 1.įIGURE 1. Options included a leather case for $3.95 and an earphone for $7.50. Of course, the battery was “not included.” The TR-1 pocket radio was introduced just before Christmas 1954 and sold for $49.95. (Industrial Development Engineering Associates) of Indiana to produce the first transistor radio under their Regency brand. The main benefits of the devices were their small size and low power requirements, so they decided a transistor pocket radio would be a good product to introduce the technology to the public. When Texas Instruments developed a process to mass produce transistors in the early 1950s, they wanted to show the advantages over tubes to spur marketing.