When i switch ON the TV it automatically switches...

Question

I have a Sony Trinitron KVG21Q1 TV. When i switch ON the TV
it automatically switches back OFF in about 2-3 seconds. Sometimes i see
athin silver line in the centre of the display also none of the
lightsin front flashes. What is the problem with my TV?It
is about 7 years old. I was advised by a person, to check
around"Vertical Out" area to see if there is any dry solders but i
didnt findany.Also i checked the whole board for any dry solders or any
shorts or for any burnt components didnt find any.The tv is old
but my grandparents use so it not muchused and they dont want to go to
a new one as new tvs are complicatedfor them to use.