I still remember when i was a little kid, and we had that horrid hybrid and one weekend watching cartoons, I watched at the picture on it got dimmer and dimmer, and shrank from side to side, and got all fuzzy. and I told my dad " the damper just went out, on it you need a new one" and it blew his mind that I was RIGHT!
Main reason I knew was, that I had stolen his book that he almost never used ( long since lost ) and read it over and over, and it told me exactly what was failing by the symptom I saw. it was this book.
http://awfullibrarybooks.net/tv-repair/