Hello, the green color is missing everything is to say to the OSD also or only by video and TV. Anyway to know if the cathode is the problem, assemble a tester with a resistance of 100K x 1W, you solder a cable at one end and the other you leave it free, the end of the cable solder it to GND on the tube plate and with Be careful you are touching the cathodes that are three GK-RK-BK, when you do that the screen gets the color you touch, if in some it does not appear the color is because the cathode is short.
Hi. You ask for help but you don't say WHAT you did in trying to solve the fault.
You have to make a technical report detailing the tensions. In your case in the green cathode and color transistor collector.
Also the video signal.
Corresponding to green.
What color does the image look like?
I commented and then we see how to continue.