Re: OMG SAMSUNG UN55F9000 Ultra HD, SMART, 3D 4K

If your TV is working properly you will get an image stating that you need to connect the One Connect.
You may have a bad LCD panel.
You can unhook one ribbon connector at a time, from the TCon, and see if you get video from the connected area of the screen.
Re-install the ribbon cable an try the next one, and so on.
The common issue with the UN55F900 and UN65F9000 is that the TV will reboot when the One Connect is connected.
This is caused by a faulty chip on the motherboard.
There is a repair...