I dont have much experience pre 1960 BUT
it sounds like you have an AGC problem causing it all.
Too much gain will clip the hoz sync pulse & tear up the pix.
Also causes sometime audio buzz, jittters, over contrast,
negative pix........
Start with adusting AGC then tube then any caps not changed
in the AGC area. Also high ohm resistors working your way down..
73 Zeno
