Mark (atomicpunk),
Hello, I am Jeff (also called here PUNK ROCK DUDE). I'm gonna get sidetracked just a second. I see punk in your user name. Are you a punk rocker or does it mean something else? OK. I was studying on the color problem with your Chromacolor (II?) Zenith. The problem sounds like it is intermittent from the way you describe it. Do you have the older flat solid state chassis, the flat 4 tube hybrid chassis, or do you have the newer vertical fold down type chassis? There is one thing common to all 3 of these chassis- the Chromacolor switch on the front of the set. The Chromacolor switch has male terminals and a female plug that it connects to. This isn't real apparent until you take the tuner assembly out. Anyway, a problem I have run across frequently on these sets is that the male terminals on the Chromacolor switch get tarnished and dirty (black looking). When this happens it can cause the front panel controls (color,tint,etc.) to not work at all or maybe intermittently work. If the Chromacolor switch terminals are dirty take a soft white pencil eraser and gently run it over them until they look clean. Once they are clean a light application of silicone spray helps to keep them from getting dirty again. If that doesn't seem to be the trouble you might try using the handle end of a small screwdriver and lightly tap on the chroma modules while watching the screen for any changes. All the flat chassis whether hybrid or solid state have 2 seperate modules that pertain to color. These modules have IC's mounted on them. One thing I have had happen to these modules is bad solder connections on the IC's. Hope this helps you out with your set- good luck. Let me know what happens.

Jeff (PUNK ROCK DUDE)