Just to give a feedback, I found what was the problem, it was the current sensing resistor on the primary side of the power supply, the resistor should have 0,22 ohm, and had around 0,40 ohm

I have this lcd tv after i turn it on, the Qilive logo appears on the screen then 2 seconds later revert to standby, first i thought it could be the led bars, if i disconnect the backlight the tv stays on, or if i leave the led bars connected but disconnect the screen the backlight stays on, then i power the backlight though a led tester i was able to see that the tv was working, then i go to menu and lower the backlight intensity to 10(from the min 0 to max 100) then connected the backlight again and the tv worked normally but when on the menu i raise the backlight intensity when reaching 64...