1964 Zenith 5111 comes to life!

[old_coot88]

Yo, way to go, Phil. Now we got a good eyeball at the color section.
To the OP: The "reactance" coil mentioned earlier is L28 (adjustment A17). Check that coil for continuity. It's a very frequent failure point in RCA and clones, and may be in Zeniths also.
And check the plate and screen (G2) voltages on the 6GH8.
A good direct sub for the tube is 6EA8, and in a pinch, 6U8 just to see if the oscillator is gonna run or not. And here's some other possible subs:
http://www.nostalgiaair.org/tubes/6gh8.htm