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#1
11-20-2004, 06:16 PM
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A little Quiz::
I have a little question for all of those out there in TVland. How many of you out there would care to guess when the FIRST color tv, with a true, isolated-secondary switching power supply (not just a buck-mode regulator)was introduced, and which manufacturer was it?
I'll give you all a hint: it was NOT Sony. 
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#2
11-20-2004, 06:32 PM
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heres the answer
shanling!
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#3
11-20-2004, 06:44 PM
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I think there was a Motorola with switching power supply in the late 60's or early 70's, it was labeled as the electronic power supply panel.
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#4
11-20-2004, 08:08 PM
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Correct
it was in 1971, Motorola introduced the second-generation Quasar,for the 1972 model year, and it had a switching power supply.the actual circuitry was not very different from toady's switchers, a doubler off of the AC line produced over 280 volts to operate the JA power suply module. this was a cold, (isolated) switching supply, using cold-side feedback, and it ran at the horizontal rate(actually synced to the sweep.) At the time, it was VERY unusual, and many technicians couldn't deal with it(I get this from reading a multitude of service articles from the '70's to early '80's),and so, it was replaced in 1974, IIRC, by a constant-voltage transformer supply, like Zenith used.
If only those techs knew, that in a decade or so, that was ALL that they would see, they may have reacted a little differently. But of course by the late '80's, by which time nearly ALL tv sets had switchers, most of those old techs had retired, SO I guess it didn't matter....
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#5
11-20-2004, 09:06 PM
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They are so complicated they have helped with the replace or toss mantality these days. I would have retired at first sight.
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#6
11-21-2004, 05:47 PM
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We had a thread on this a few months back, Sadly most of those motos got junked years ago due to techs that had no idea how to service a switching supply and rebuilders that were unreilable. Once I got the hang of them I serviced all the JA panels for our shop and others in the area. Didn't make much difference though as they were already on their way out by then. Once Panasonic bought them in 1974 the sets then became Japanese (Panasonic) guts and American crt and cabinet.
Last edited by captainmoody; 11-21-2004 at 06:30 PM.
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