Switches on and off automatically

"@malhabibi first of all, check for any capacitors that are puffed up or leaking. Make sure that all your cables are properly connected. Next follow the Samsung trouble shooting for no power flowsheet:""

Check the various cable connections first.

- Check to see if there is a burnt or damaged cable.

- Check to see if there is a disconnected cable connection or a connection is too loose.

- Check to see if the cables are connected according to the connection diagram.

Check the power input to the Main Board.

Check the following circuits.

• No raster appears: Function PBA, Main PBA, I/P PBA

• 55V develop but no screen: Main PBA

• 5V does not develop: I/P PBA

Check the voltage in and out between the IP↔ Main Board, between the IP↔ Panel, and between the Main LVDS Boards.""

Next you do want to take a look at the transformer on the inverter circuit as well as the caps on that. the other possibility is an overheating MOSFET.

Let's see if we can find the right schematic for your board."