ue55f9000 stuck in reboot loop at logo screen

[Jothow]

Hi there,
I have a Samsung UE55F9000 and 2 days ago it's stopped working. It's stuck in a reboot loop on the logo screen. I've tried disconnecting all inputs and changed power supply and socket to no avail. If I keep one connect box disconnected from the TV it then stays on but displays an image telling me to reconnect it - as soon as I do it reboots and keeps doing so from logo screen, I can't get to any menus or inputs etc... .

Any help would be much appreciated

John