Is it the CRT or ???

[TinCanAlley]

Lately my Zenith Chromacolor II has been having an issue and I'm not sure if it's a gun in the CRT or one of the boards that controls tone. I'll be watching and all is well, but out of nowhere the screen will flicker and take on a light to very dark magenta tone. Sometimes it will stay this way for a bit and other times it will go away in seconds. I can go days without it happening.

I know it's not the video driver board as it is a new board and this happened with the old board. I did a test of the CRT and even did the rejuvenation. All is well as far as the testing unit is concerned. I've even removed all the modules, cleaned the contacts and replaced. None of which helped.

I am about to catalog all the main caps to replace them as I have jailbars and a medium dark horizontal line that moves up the screen. I'm not sure they would have anything to do with the problem, but need to be done anyway.

So, any suggestions?

Thanks in advance.