Prototype set is here

[Steve McVoy]

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.