I messed around with it some more today. I rechecked all the components in the horizontal section and tried new tubes again. Everything is normal. I experimented with changing the screen grid resistor in the hor. output section and found that with the resistor shorted out I got about 16 v. on the cathode, indicating close to normal current, and width that is about 1/4 inch short on each side. Boost is still low at abut 560 volts, and actually dropped a couple of volts when I shorted the screen reisistor. Something is still wrong, but I'm sure I can get the small amount of additional width needed somehow.
http://www.earlytelevision.org/spart...storation.html
I don't have a suitable replacement flyback to try.
Any ideas?