Another Zenith find, a 4 tube Chromacolor hybrid!

[jpdylon]

The two tubes are interchangeable.

The blooming and poor focus are usually due to a failing HV trippler (red thing) There used to be an ECG replacement to put in its place but I don remember the part number... Got an HV probe? Check your focus and ultor voltage.

The video problem is inherent to these sets. They have poor DC restoration resulting in low black levels when there's lots of Y information in the video signal. Given the colors on that screenshot, I think your CRT is fine.