you know what might have happened is,
the input is bad for some reason and the top of the image was distorted so badly that the television decided not to display it at all.
and when you seen the picture cut in half, it might have been a safety feature to prevent obnoxious electricity from making its way to the video output 'controller' .. as if it say, the television refused to play the distorted image because there might be extra voltages in there somewhere that could damage the controller.. so instead of playing the video, there was a function that cut the video in half (maybe software function) and what you seen was the result.
the circuit as a whole might be collapsed because there is a loose connection somewhere.
or
maybe there is...