This is a symptom of what is generally a leaky or open filter capacitor in the vertical sweep circuit. Vertical foldover, where the image actually is reflected upside down an inch or so into the top of the picture, is common in this problem. There is an IC that controls the signal and sometimes it needs to be replaced, but more often it's one of the filter capacitors nearby. Any competent technician can fix this problem and the capacitors only cost $2-3 or so if you can find the correct value at Radio Shack (that's if you pay full retail for them). A good service tech will probably have these on hand. Testing them is easiest with what's called an ESR meter (stands for Equivalent Series Resistance) and the better ones don't require you to unsolder them from the circuit board before testing. The most expensive part of this repair is going to be the technician's labor. They're good TV's, this is just a problem common to most TV's in general - mostly due to aging of the capacitors from years of heat. A higher quality replacement capacitor will solve the problem for the life of the set.
