I dont remember projos but on a direct view the
CRT being weak causes that. They built it to kill the video
if the CRT is weak. I asked Sony why they did it & they
told me they didnt want sets with bad pictures !
So odds are one or more CRT is weak. Turning up the
G-2 a little on the offending tube (s) sometimes stops it
for a time.
73 Zeno