Might be caused by a faulty capacitor on the power board. There are many documentation on the web about this problems with samsung TVs. Here is an example: https://www.youtube.com/watch?v=xGbAgbZr...
https://answers.microsoft.com/en-us/windows/forum/windows_7-desktop/how-to-rotate-my-screen-with-hot-keys/def8e98e-b475-453c-963f-19764e341707 Maybe this will help :)