Quote:
Originally Posted by John Folsom
John,
That Sylvania of yours is a very curious beast. Sylvania definitely did their own thing, design-wise. I have several 10" and larger sets that use RF high voltage power supplies, and have always enjoyed them. I have never seen any other 40s vintage TV with a large capacitor across a fuse. Seems curious, probably not the best design. But a really interesting set from a technical point of view. Thanks for posting the service data.
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Thanks John. To me the design seems straightforward because it's the first TV I was exposed to as a kid. I participated when my Dad did repairs, or when Gus Wall, our TV repair guy would make a home visit. And I actually enjoyed the smell of selenium rectifiers. Well, I admit the large cap across a fuse is strange..
From looking at old texts, data-sheets that I looked at nearly 50 years ago, and old magazines, I think Colonial Radio cut and pasted patented circuits and did some of their own weird stuff like the paralleled 5U4 and 7X6. The horizontal circuit seems to be from RCA. The RF HV, I'm pretty sure, is from Spellman who manufactured HV supplies for TV's. I think that's where they got their start.