Did some resistor checking tonight and replace a few high ohm resistors that had drifted out of tolerance. Not badly out but like a 2.2m that measured 2.8m, 1.0m drifted to 1.4m, it seems to have improved the sync and vertical lock, they were all in those sections.
The Contrast control was having no effect except a slight increase in Contrast all the way at one end, I opened up the Pot and found this:
It's a 1000 Ohm Pot and it's stacked with the Brightness control, according to the schematic it's not the same as used in the 630, I had hoped it might be since I have some spare parts for one of those.
Hopefully I can find a good Carbon in something else and transplant it to this control.