TV Malfunction?

Originally I posted this in the wrong place, hopefully you guys can help me out with this.

I have an old TV (JCPenny RCA made in November of 1983) and I love it, except for one little flaw. Whenever there is any signifigant amount of the color white on the screen the TV makes a humming feedback static type of noise. What is this? Anyone have any idea? Id really like to fix this, since the vintage TV matches my stack and they are getting harder to find in such good condition. Thanks!