Why are there vertical striped lines on the tv

Hello, I turned on my samsung ue50f6500sb tv tonight and all I have is vertical striped coloured lines on the 55" screen - I live alone so no one went near it. Its wall mounted and has never had any issues before. Can anyone help me? I'm slightly techie so I may be able to carry out some repairs if necessary.. I took the back off the tv and messed with the board which has the hdmi ports etc and it makes no difference. Any help at all or ideas would be greatly appreciated.

Thank you, Phill