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 half of a circuit that is collapsed, causing the other half of the circuit to work double time.. and it got really hot, enough to melt a soldered joint.. and now you have a loose connection.
maybe you find the loose soldered joint and apply some solder.. and if the circuit is working double time still.. it will only get hot and melt the solder again.
that is why it is crucial to do a circuit test.