[DaveWM]

looks like some hum or maybe ground loop effecting the pic. what is the video source?

for snow look at cleaning the tuner, removing the shield and q tips with contact cleaner. work carefully, you dont want to break wires to the tuner, nor do you want to just soak it. Some tuners have wafer switches others use the strips on a turret, those are easier.

Snow can also be a weak RF tube in tuner of a blown balun.

turn the color down or get some black and white programming on, observe the quality of the pic. check for color fringing. check focus, little things slowly make a better pic.

get a cross hatch and check for linearity, use dots for center converge, cross hatch for edg convergence.

weak contrast can be a weak video out cathode bypass cap, but it looks pretty good to me. I would focus on proper setup (grey scale, degauss,linearity,purity, focus,converge). Don't expect it to get a lot better, hard to tell if the focus is off.