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#1
10-02-2007, 10:52 AM
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? Prewar DuMont flyback on eBay ?
I see this potted transformer on eBay, claiming to be a DuMont flyback... I have no experience on DuMont prewar sets, and I've never seen a cylindrical potted flyback. And I think all the prewar sets (other than small-screen kits) have direct step-up HV supplies. So is this a horizontal output transformer mis-labeled as an FBT? A high voltage transformer? Or just a plain misprint? Might be a rare item!
Charles http://cgi.ebay.com/NOS-DUMONT-TV-TE...QQcmdZViewItem
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Collecting & restoring TVs in Los Angeles since age 10 
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#2
10-02-2007, 10:57 AM
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It is for the 1946-47 RA-101. It is a flyback.
All prewar sets except for the German E1 had transformer HV supplies. http://www.earlytelevision.org/e1.html The E1 was by far the most advanced prewar set, using a low tube count, flyback HV, and a rectangular CRT.
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#3
10-02-2007, 11:47 AM
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No kidding... I have an RA-101 and I didn't recognize it! I'll have to look at the schematic again on that set... I thought it was a standard HV transformer step-up from the mains supply like the prewar sets, as you say. I might be wrong on my terminology. I was thinking that in order for it to be a flyback, it had to do both jobs of Horizontal Output and also HV supply.
Charles
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Collecting & restoring TVs in Los Angeles since age 10
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#4
10-02-2007, 11:53 AM
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You may be right about the transformer. I'm out of town and can't look at my sets, and it may be that it goes in the RA-102 instead. It is a horizontal output transformer, but I can't recall if it also provides high voltage.
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#6
10-02-2007, 06:28 PM
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It's the horizontal output transformer for the 101 "A" version (60 cycle HV). It might be used in the 102 also, but I really don't want to pull the front panel off my 102 to look.
Chuck
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www.myvintagetv.com Learn from the mistakes of others - You can't live long enough to make them all yourself.
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#7
10-02-2007, 07:37 PM
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Yes, it is the Horizontal Output transformer used in the RA-102 to drive the H deflection coils. The HV though is generated by a separate pulse transformer with its own oscillator triggered by H sync.
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Tim
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Linear Mode
