[old_coot88]

Originally Posted by venivdvici

A few years earlier, she blew almost eight hundred bucks of her late husband's insurance on the new set and complained when all her shows weren't in color. He explained most shows weren't broadcast in color and she should save her money and return it for a nice black and white set. Nope. She wanted to be ready for the color revolution. She'd read in Life it was coming.

TThat sounds like a few of the old biddies i ran into during my years as a road techie (as well as an in-shop techie).

The problem was the image, though centered, was very small. As usual, he wore his sneakers and kept one hand in his pocket as he worked. He started by testing the tubes--twenty-eight of them!--and found a short in a filter capacitor. That blew one of the 5U4 rectifiers. After replacing the bad parts, the set worked good as new and he lived to talk about it.

Thanks for any advice.

Well, first off i never knew a road techie who 'wore sneakers' specifically for electrical safety or kept one hand in pocket while working on a set in-home. I never knew one to routinely carry a tube tester into the home either. The test for a given symptom is to substitute the suspected tube(s).
But to address your specific scenario of a shrunken raster on the CTC-7, the very first thing the techie would know to do is substitute the 5U4s. But since there's no improvement, this indicates the 5U4s are not the problem. However the shrunken raster exhibits a hum bar, that is, a dark band that slowly scrolls vertically through the picture, accompanied by an S-bend in the sides of the raster that scrolls with it. This is the classic symptom of the main filter capacitor gone bad. The set would have to be shopped for this repair.
But note that the raster could not be "very small" and still display a picture. It would be pulled in maybe an inch or two from the sides along with the telltale hum bar.