Okay, I maybe tracked down a possible cause, but I'm not sure exactly what might be wrong.
I followed bad voltages around on the board, and I found one that I can trace back to the D PCB through the Vertical Position Signal (which seems to be what's FUBAR).
The Base of Q255 connects to D257 and to the D PCB through Pin 19 of P302. This should be at 8.3V but it's 1.3V. This has got to be wrong I'm thinking.
This 8.3V is supposed to be driven by Q202 and Q203. I actually did think that this might have been contributing sometime a couple weeks ago, so I pulled these two transistors and they tested okay with a simple diode test out of circuit.
I measured the voltages on Q202, and the other two voltages are pretty close to correct, so something here is amiss.
Again, I still don't really understand this stuff totally, so for all I know, the 1.2V is being pulled down from the other side where D257 and Q255 live.
This is what the area looks like:
