Here is a pic from an old RCA color service book that illustrates classic loss of color sync. The "RGB" bands are a giveaway:
The bands can be thin or wide, and they can move at different speeds (or not at all). I struggled with a color sync problem on my CT-100:
The next pic shows a color bar pattern (yes, really) when the sync was totally out of whack:
Those are examples of crazy bad color sync. As old_tv_nut suggests, your problem may result from more subtle causes.
Don mentioned purity, and a problem with that can create broad areas of wrong color, not so much in horizontal bands. The next two photos show the result of moving my CTC-11 across a room and turning it 90 degrees from its previous orientation. (The cornfield should not be red, and Dorothy's mouth should not be green!)
Degaussing quickly cured that problem.
I don't have a specific suggestion for you, but perhaps these examples will help you identify what's going on, or at least rule out some issues.
Phil Nelson