![]() Whether a pocket portable was seen behind closed doors at the Hannover Fair in March 1955, is yet to be determined (4).A Regency TR-1 (with Intermetall transistors) would be shown at the Düsseldorf Radio Exhibition in 1955 by Intermetall (6).įigure 1: Circuit of the "Telefunken TR-1" dated August 55 (top) compared to the "Regency TR-1" from November 54 (bottom). (There were, however, scarcely any alternatives.) The speaker was similar to the Jensen model used in the Regency.The claim that the development and manufacture of the Telefunken TR-1 took place in the summer of 1954 (3), is probably questionable. Moreover, they used the same components values, where possible. Of course, the RC components to neutralize the IF stages had to be changed. The intermediate frequency was virtually the same. This was necessary to reduce the mixer transistor noise factor. Also since they had poorer RF characteristics, the IF stages were increased to three and the self-oscillating mixer was replaced by separate mixer and oscillator stages. Because these were pnp types, the supply voltage needed to be reversed. It could be thought of as follows (but unfortunately there are no relevant authorities):They adapted the Regency’s circuit to their available transistors. After the initial pioneering work in the semiconductor factory at Ulm, it is clear that the Hanover factory became active only after the release of Regency receiver. Other experimental circuits of the time, as well as the upcoming transistor receivers from 1955 below, deviate from its circuit design significantly.A great similarity is apparent when comparing the circuit of the "Telefunken TR-1" with the "Regency TR-1" (Fig. The circuit of the self-oscillating mixer stage, the base bias voltage of the second IF stage from the AF power stage, the unusual IF of 262KHz and the supply voltage of 22.5 V are all characteristic of the device. It was a true international sensation (2).The circuitry of the Regency shows some peculiarities. It was the first mass-produced transistor receiver in the world and arrived earlier than the professional world expected. In the USA on the 18th October 1954, the "Regency TR-1," developed by Texas Instruments was launched on the market. Here we add the following commentary to the article "Telefunken Pocket Radios from 1955-1960" in Funkgeschichte Nr. Translated from: Gebert W Anmerkungen zu den Schaltungen der ersten Transistorradios Funkgeschichte 115 (1997) 241-44 by W Gebert and M Burgess from Sony Corporation TokyoĬomments on the Circuits of the first Transistor Radios In French: TSF for Télégraphie sans fil.Īll listed radios etc. Here you find 3861 models, 3726 with images and 932 with schematics for wireless sets etc. See "Data change" for further contributors. The first SONY imported to the USA was TR-63 in 1957. GE has also built a pocket transistor radio in 1955 as models 675 to 678 depending color. The very first commercially produced transistor radio was Regency TR-1 from October 1954 followed by Raytheon 8TP in spring 1955. It uses the following transistors: 2T51 (oscillator-mixer), 2 x 2T52 (for IF), 2T53 (AF driver) and 2T12. TR-55 was the first transistor radio produced and sold in Japan. TR-55 is a superheterodyne and can also be used with earphone. This model, TR-55 (TR 55, TR55) has then been produced as the first SONY Transistor Radio for sales in August 1955. In April 1955 SONY has built a prototype of it's first Transistor Radio, the TR-52, looking like United Nations Building - but TR52 was never really released because of the front-plate "ungluing". Very small Portable or Pocket-Set (Handheld) ![]() Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 2.5 inch = 6.4 cm.We've all done it! Slipping some sleeving over the metal part of the probe so that just the last mm is bare can help. a slip of a probe can short adjacent pads together, which can cause extensive damage if you're unlucky. introducing trouble where there wasn't any before.Īnd be careful with your voltage measurements. Sometimes, especially with cheaply-built compact gear like this, changing bits on spec can sometimes result in damaged tracks etc. power amplifier or power supply) or a set which has lived in a very warm climate, of course. Japanese electrolytic capacitors are not renowned for going faulty, especially in a battery-operated radio in Glasgow! It may be a different matter in a hot-running circuit (e.g. Do you have an ESR meter? Even if you do elect to change them, it would be interesting to check the removed ones and see if they really were below-spec. Well done! Always worth doing the simple stuff first before getting too stuck-inĪs this is an "educational project", don't just change the electrolytics en masse.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |