I've checked the voltage sent to the backlight and it wasn't ok, thus decided to buy the power panel https://www.piese-servicelcd.ro/www-piese-servicelcd-ro/eshop/1-1-POWER-BOARD-SMPS-PSU/7-2-VESTEL/5/3001-17IPS62-VESTEL
hopefully will fix the problem
when I've put the tv back on the wall, surprise! tv started to work again, ,must be some power leakage issue from the power supply