Jumpy [B&W] composite video signal from 1974 dumb terminal

[MightyFrame]

maxhifi and old_tv_nut, thank you VERY much for this very helpful feedback. I'll see what I can do to get the old crt working.

My goal is to do both, capture AND view, but knowing what the problem may be is certainly a great place to start.

I'll work on this, and report back here when I have some progress.

Thanks again!
AJ