Toshiba 40RL938 LED Backlight Problem

Hello people,

I have a Toshiba 40RL938, which is an LCD TV with LED Backlight. Since yesterday, the backlight isn't working after 1 second. More specifically, every time I power on the TV, the backlight works fine for 1 second, then shuts down, while the TV picture is still visible if you shine a light on it. Sound works too. That means that for one second in every power on, I can see perfect image, then the backlight goes off.

Someone told me that the LED backlight is dead, however it isn't since for that 1 second at every power on, it works perfectly.

It's like something is forcing the backlight to shut down after 1 second.

I've tried leaving the TV overnight out of the power socket, and even changing a power socket, but none did work.

Any Ideas?