I finished recapping the set, and tried it out, only to have first a dim raster with the horiz frequency way off, then an intermittent bright white raster with greatly reduced horiz width. The sound worked on a few channels. Then I heard some not-too-good sounding noise comming from the chassis, and I looked around back and saw it was comming from the damper tube which was glowing bright red. I unplugged the set, and as I didn't want to run it anymore under those conditions, I put the chassis back on the bench and poked around with the ohm meter. I found 3 problems.
1. The horiz hold pot itself, when I turn it (or sometimes even when I don't) with the ohm meter on it, it jumps erratically, and when I tap it with my finger, it reads completely open. I tried spraying some cleaner in there and turning the control a bit, and no difference, it needs to be replaced.
2. The flyback: it's supposed to read 250 ohms across it, it reads 600 ohms.
3. The HV filter capacitor 250pf 20kv, it's not even there
, I don't know how I didn't notice this one before.
At least the 16GP4 is good.