zenith 35" tv vertical size has shrunk

My zenith 35 inch tv vertical size decided to shrink about 5 inches while we were away on a month long trip. the tv was unplugged from ac and antenna connections. is this caused by a capacitor changing values on the vertical output board ? is it worth doing a check of all the parts or getting a replacement from tvparts.com and just swapping boards.

ps: i have been in electronics about 40 years in the amateur radio field and two-way radio service..

thanks, ed