Boy this is like being a detective. The RGB outputs are not on the CRT board and neither is the bias supply. I'm surprised the circuit side has the silkscreened labeling. That is great. Ok, referencing your picture #1 posted 8/29 at 105pm, the RGB video signals are the three shielded round black shiny cables in the bundle coming down to the left behind the metal. Do those go to a connector on the main board? I would need to see the circuit side of the main board where those connect and the surrounding area. I didn't think those black TO-5 case transistors would be the outputs because of the part# shown. Are there 3 identical transistors possibly mounted on heatsinks that are labeled R-OUT, G-OUT, B-OUT or something like that? I would need to see the circuit side of that area. Unfortunately, do you have a large metal shield on the underside of the main board? I hope not. Also that main board might slide out enough for a picture of it's circuit side. If it has the same silk screen wording it will be easy to trace.
Larry G
Larry G