My tv keeps turning on and off on the blue screen for hours.

my tv flickers on and off when going through the point of booting up with the proscan logo, however it tends to "trip" itself off and switch back on itself on repeat until fully powered on, which has taken anywhere between 5 minutes to literal hours on end, the longest was almost 18 hours as it was still flickering upon waking up this morning, when it turns on it stays on and everything's good, but its very temper mental so any advice to try fix would be greatly appreciated