while trying to help timmy I was doing some research. thought I would start a new thread with a better title for search on.
here is the video of a problem that I have seen on some of my sets where the CRT is getting a bit weak.
https://www.youtube.com/watch?v=39Dl...CVtyRrqXVtll-g
and here is something that looks like a possible fix (I guess this problem was worth looking into back in the day).
http://www.google.com/patents/US3247418
the above circuit adds a neg going pulse to the G2 grids in addition to the reg positive pulse added to the plate of the video out (cathode of CRT). Effectively increasing the bias to further cut of the CRT during the retrace