I went and read your question. I am not a TV repair person.

But your question was akin to asking:
"My car won't start. I think it needs a new battery.
It never gave me trouble before. What is wrong with it."

Problems like these are nearly impossible to diagnose over the
internet. And with virtually no info that makes it even harder.

What have you tried. What makes you think it might be a switch.
If you can do the work yourselve then you must be able to do
some basic diagnostics. Otherwise you don't belong inside a TV.
Lots of highly charged capacitors in there to provide quite a shock.

As for PeeWee, he is a knowledgable person about this stuff.
But he is not the only person on this site. When you address
your question to a particular person then other people mite not
reply even if they can provide info about the problem.

Sometimes getting good answers means asking the right questions.
Little or no info at all virtually guarentees no answers.

I'm sorry I can't be of any help for your problem. I understand
a considerable amount of electrical theory down to the atomic
level (math and physics major), but I couldn't begin to fix a TV.
And I'm certainly not qualified to troubleshoot over the internet.

I do hope you find the answers you are seeking.

Good luck.

Pooh Bear

The PeeWee that posts on this site is a very nice person.
He has answered several of my questions before.
And also a lot of good people have left the site in recent months.
Even I don't answer as many questions as I could anymore.

I still hope you find the solution to your problem.
But I am certain you have killed any chance of finding it here.

Pooh Bear