Signs of a Failing PictureTube

[Console User]

What are some signs and symptoms of a CRT that is about to go out?

My 1991 Zenith has an issue but don't know if it is to do with the picture tube? When I sometimes turn it on the shade of yellow on my meter bar of my converter box is the normal golden yellow color it has always had. The next time you turn the set on it may be a real bright yellowish color. This can give a greenish yellow tint to faces when this happens. If this happens I just turn the set off for a few minutes and then power it back on and it is okay then. Also, seem to have some wavy lines appearing in the background at times more noticeable with certain colors on the picture tube.