need help for RCA -27R410T - 27' TV

[niljaviya]

HI
i have 27" RCA TV model 27R410T
it works excellent and very good picture, b4 few days ago the problem starts
after working 20-30 minute when TV get hot or if u change channal picture is gone(voice continue) and B/W strips which are distructed video signals are starts to roll

if u power off for 15 minute, it start to work agian, more over i remove the cover behind TV and put one fan so it works but if u change channal than again problem start.

when it get hot than problem occurs?? which IC or transistar i need to change if any expert can guide me i will grateful to you ? where i can get it in canada? how much cost ?? if u know than thanks a lot.
i can not decide do i repair or not??

thanks
NIL - canada