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

[MightyFrame]

Originally Posted by AlanInSitges

AJ do you have access to an oscilloscope?

Sorry for the delay, but YES, indeed I do have access to a scope.

I waited to reply until I could actually record a short video showing the composite video output on this scope.

It's a short 7-minute video where I go through various settings on the horizontal to hopefully show a good full-spectrum of the signal.

https://youtu.be/ZphFzpkUtto

Does this help to figure out what might be going on with this jumpy signal?

Or, should I do some additional tests on the scope, at your suggestions?

Thank you!
AJ