And now, for the grand finale!
After a few tweaks to the demod driver transformer, we now have color bars!
Purity and convergence are still a mess, but this proves that 99% of the parts in the chassis are doing what they are supposed to do. That makes me very happy indeed, since this thing was a basket case of prior hacks when I first picked it up. Twice rebuilt picture tube, melted insulation, frazzled video peaking coil, bad solder joints, and more incorrect connections than I can count on both hands...
Along the way, I also found that whoever replaced the flyback had mistakenly swapped terminals U2 and U3, which supply pulses to the blanker and burst keyer tubes. Not sure how much difference it makes since the voltage difference in the actual pulses is small (50 volts), but I fixed it anyway for the sake of correctness.