Whew, finally getting somewhere with this thing.
After getting a schematic I found a miswired cap causing the blank raster.
After that I spent a couple hours trying to get it to work with a DVD player with no luck, finally I figured out I could get a picture with a pair of rabbit ears but I had no sync at all.
After a few more hours poking around I figured out that the
12AU7 sync sep tube was losing it's heater connection, it would work sometimes but not others and because it was the heater connection there was a delay between wiggling the tube and the set resuming operation so it was difficult to figure out exactly what was happening.
I wonder if all the half fast repairs that were done to this set were done to try and fix this same problem? or perhaps I damaged the socket when I was recapping it?
Last of all I figured out why the DVD player wouldn't work, I'd plugged the RF modulator into the optical sound output of the DVD player instead of the video connector,
So here it is, 2:40 a.m. and the set is playing pretty well!
I still have to change the tube socket, for the time being I've found the sweet spot where it'll work but it's not very solid.