Hi Tim,
Thanks for posting and welcome to VK!
I took the below pictures of what Riders has on your RC-200. Sometimes Sams tends to combine more than one model and in doing so makes things more confusing. It's possible you have a 200 chassis with a 201(2 tube) tuner. You can take a look and see if this Riders info closer matches what your set has. Also there is some instruction in the alignment section on removing the AGC tube and substituting a negative 3 volts on the AGC line. I believe that set has gated AGC so It would be interesting to see if doing that has any effect on your signals, both from the antenna input and direct video in. You should be able to click on the individual photos to zoom in.
https://www.flickr.com/photos/152661...57713634054282