Vision FM Teletuner

[Jonathan]

I purchased a Vision FM Teletuner. It is similar to a UHF converter is design, but receives FM on the FM band and pipes the sound through channel 2 or 3. When the unit is switched off, it passes the antenna signal.

Inside it cosists of a hot chassis with stinky selenium rectifier, a variable condensor (not like Zenith's FM tuning methods at all, so this must drift like crazy, the plates have wide gaps between them), a 6BA6, a 6C4, two large isolation transformers for the antenna input and output(looks more like audio transformers, I have no idea how RF passes through them so easily, if at all), an electrolytic multicap, and a plethora of inductors and capacitors. It looks cheaply made and looks like it'll barely perform well at all. It did have a 90 day warrenty, so it must be crap.

But, I love a challenge. Would anyone know if any sevice data existed and where one would find it? I'd love to play around with this one.

Thanks.

Jonathan

[Jeffhs]

Originally Posted by Jonathan

I purchased a Vision FM Teletuner. It is similar to a UHF converter is design, but receives FM on the FM band and pipes the sound through channel 2 or 3. When the unit is switched off, it passes the antenna signal.

I It looks cheaply made and looks like it'll barely perform well at all. It did have a 90 day warrenty, so it must be crap.

But, I love a challenge. Would anyone know if any sevice data existed and where one would find it? I'd love to play around with this one.

Thanks.

Jonathan

I'll be darned. I didn't realize anyone else other than Regency made these things. The Regency FM converter, which they called the "FM Televerter", came out in the '50s and also allowed FM reception on an unused TV channel (don't recall whether the output of these was on 5 or 6 or a lower channel, though channel 2 or 3 somehow rings a bell as I've seen the Photofact for the Regency converter, which specifies, IIRC, that the output will be on one of the latter channels). It operated on the same principle as UHF TV converters did, although, as you mention, it did drift quite a bit (these FM converters did not have AFC to the best of my knowledge), and were not very sensitive or selective--making them useless in anything other than strong signal areas. Even then, if you were in an area with many closely-spaced FM stations (say in the heart of a large city or in the near suburbs) you could and probably would have problems separating the signals because of the overlap, especially in the 100-MHz part of the band which is rather crowded in many metropolitan areas.

It is well to remember that these converters came out in the very early days of commercial FM and did not work anywhere nearly as well as any halfway decent modern bookshelf or component stereo system (see my comments above). Like UHF television converters, the FM adapters were a cheap and dirty way to get FM through your TV, although most people who had them probably used them only until they could afford something better. The converters then were relegated to the attic or basement and forgotten, or put out for the trash and sent to the landfill. You didn't say where you purchased your Vision FM Teletuner, but I'd hold on to it, as you may never find another one like it (though you may find the Regency FM Televerter occasionally on ebay or even at garage/yard sales or hamfests).

As for the service info, schematic, etc., it shouldn't be too difficult to find for your unit if you do a Google search on the converter's model number, if available. That failing, I'd try a search using the keywords "Vision Teletuner". This may or may not turn up info on your converter, but, IMHO, it's worth a shot. I would also try Sams Photofacts, again if you have the model number.

Good luck and very kind regards,

[wa2ise]

The tubes probably have low usage, so are likely to be good. Replace the selenium rectifier with a silicon diode like a 1N4004 (the current demand of this circuit is likely low enough that the selenium rectifier's internal resistance didn't make the voltage sag much at all so you won't need a series resistor) and replace the electrlytic caps. All the other caps are probably ceramic, and normally won't need to be replaced.

90 day warrenty was standard practice for all consumer electronics back then.

[Jonathan]

There is no model number to be found. Pilot and Regency made TV converters as well. It isn't a clone of either as far as I can tell. I might have to blindly go at this, but all I'll need to do is replace electrolytics and the selenium rectifier. It should be easy to get working, but, like you said, probably won't work very well.

Thanks.

Jonathan