No color on late 1970's RCA's

[Chad Hauris]

I've got several late 1970's/early 1980's RCA's, portables and consoles, chassis CTC-86 to 101, that have problems with either no color, or that color will only appear when the fine tuning is tuned off the channel, or unstable color. These sets appear to use a single IC for chroma. Has there been a documented common problem on these with chroma? Thank you.