Certainly appears to be a problem with the red vertical convergence circuit. You've switched the feeds to the yokes and the problem followed the red vertical convergence circuit.
You've checked all the resistors and capacitors and they are within tolerance. I guess you've already tried replacing IC804 a second time, so that leaves the DCU.
Yes it would be a great idea to replace the entire Convergence Out PWB (SSB-5051A-M2. Problem is it's showing as NLA from my distributor. Perhaps a Google search will help.