Zenith 25mc30 DC restoration.

[old_tv_nut]

There have been tons of discussion here about the lack of DC restoration on all tube color sets after the CT100. You are seeing it the way it was designed.
Consumer Reports complained about this yearly until solid state chassis with 100% DC restoration came along. People nowadays don't remember or never knew how these old sets performed compared to today's, and yes, it's striking.
To improve it requires modification from the original design. I don't know if you can find (here or elsewhere) posts of modifications to this chassis to improve/correct it.
You have to consider whether you want it as a true example of how it was or improved.

[Alex KL-1]

Intriging. Being a fanatic for DC restoration, making it even for B&W portables, I first think that the DC restoration is a rule for color TV (years ago). But then, reading some schematics and restoration reports, I concluded that several models not have it then (since I not read all schematics of all models, of course ;-). Then all tube-based color ones lacked DC restoration? Interesting to know.
Even considering the low light output, the colors will not strongly mistrack with this?
I know the set without DC restoration have a average light output, so this can account for that, along with tracking, I guess... (and so more I bet)

Here in Brazil color comes late, in 1972, but the schematics that I seen, of hybrid sets, have DC restoration (at least for the ones I got schematic), but I bet the track are poor, since not have stabilized PSU, video out tube will drift etc, and color sums "high level" (like most out there, also), using the grids of CRT as input for the color signals. Since I born in 1983, I only seen one of these hybrid sets working. All others are transistor ones with fully DC restoration... so I have almost no experience in watching one with this image properties.