Zenith 1979 Chromacolor II - No color

[Palinurus]

I recently bought a 1979 Zenith Chromacolor II (chassis 25KC45, model K2518M). When I tested it out it had no color, except for a bit of yellow here and there. I adjusted the grey scale and the yellow went away, but I'm still trying to troubleshoot the color problem. Was there a factory reset button on these TV's? I'd like to pursue the simplest possible solutions first.

I'm thinking that I may need another chroma module. Mine is numbered 9-89-H. I watched a Youtube video of a restoration of a 1977 CCII which had a module that looked very similar to mine. Were some of these parts interchangeable, despite the different numbers? Any help would be greatly appreciated. Thanks.