Power boards measure the return current from the backlight and if there is a difference between strings then the Power board will cut all power.. so disconnecting the Mainboard from the Power board DOES NOT point to a faulty Power board if the backlight does not come on!!
Measure the backlight’s return loss to find if the backlight has failed because ‘most often’ this will be the cause of the Tv switching off.. power cycling etc..
If you find the backlight has failed sell it for spares because unless you have experience with the LCD screen you will break it !
Power boards measure the return current from the backlight and if there is a difference between strings then the Power board will cut all power.. so disconnecting the Mainboard from the Power board DOES NOT point to a faulty Power board if the backlight does not come on!!
Measure the backlight’s return loss to find if the backlight has failed because ‘most often’ this will be the cause of the Tv switching off.. power cycling etc..
If you find the backlight has failed sell it for spares because unless you have experience with the LCD screen you will break it !
Tony