kaputzer wrote:
I have a 12 year old 35" Zenith that loses the picture after 10-30
minutes of viewing.
A white vertical line centered on the screen appears and then the
screen goes blank.

Any ideas on the root cause or component failure?

It was plugged into a surge protector. Lightening was in the area. I
was not home.

kaputzer

Troubleshoot and repair the vertical deflection circuit in the tv set.
Common problem on that vintage of Zenith tv.