I changed the value of the resistor on the wiper of the vertical lock form 3.3m to 4.7m and was able to get a lock on the vertical. However, by replacing other components, the image now looks like this and this.
20190217_111017_004_01.jpg
20190217_111017_005_01.jpg
I think it's something in the video sections affecting the sync signal before it gets stripped?
I've replaced most of the components in the vertical and horizontal sections, though that's made the video worse than what it was before.