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Old 03-29-2012, 02:39 PM
Steve McVoy's Avatar
Steve McVoy Steve McVoy is offline
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Join Date: Oct 2002
Location: Columbus, Ohio
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I've just about finished the documentation of the schematic.

http://www.earlytelevision.org/rca_color_prototype.html

There are a few pieces missing, but nothing important. Here are the significant things I found.

1. There are only 3 triode sections available for CPA switching (V24, V25A). I suspect that a sync cathode follower (V25B) was added after CPA was removed, so that would make 4 triodes. The Rauland switching took 5 triodes. How did RCA do it with 4?

2. The chassis has a pot in the cathode circuit of the horizontal output tube labeled "phase". How would that have been used in CPA?

3. Though there is a complete vertical dynamic convergence circuit (V27A), most of the horizontal circuit is missing. There is a triode (V28A) connected to the convergence transformer, but no sign of any controls, other than a remnant of fine wire connected to V28A plate. I can find no place that the controls could have been mounted.

Next I'll fire up the reference oscillator/amp and see if I can find what frequency it is peaked to.
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