@eslahcen you have not told us what you have checked. The no video issue can be related to a bad backlight inverter circuitry. A simple check for that would be to darken the room and turn the TV on. Then use a flashlight and angle the light at the screen on different areas. You might make out some shadows or see s slight grey color. Your model uses an backlight circuit on the power supply board. So replacing either backlight strips or the power board (the least likely) should repair your TV. Let us know what you find out so we can help you further.