My 9-10 year old Sanyo 27" (I'm sure you're all laughing now) TV has thin vertical
Line/lines going across the TV, especially at start up. As of now I fix it by smacking the side of the TV moderately hard with a rubber mallet. I'm surprised I haven't broken the plastic cabinet yet! The picture comes back after a few good hard whacks. When the picture comes back and is normal, just the slightest touch to the TV can throw it out of whack again. Any answers?

Same thing that's happening to my 8 yr old Sanyo 27". Vertical is going out. Not worth fixing. I'll have to try your mallet suggestion.. my hand hurts ! HAHAHAHA