Is the display unit broken

@rjpharoah horizontal lines are most commonly caused by a failed panel. This is not repairable but would require a new panel. To be sure of this we would need a complete model number and would need to see those lines. If you can, post some images of what your screen displays with your question. That way we can see what you see. Use this guide Ajout d'images à une question existante for that. Panels that size are hard to come by and may cost more than a new TV. Remove the back of your TV, check all the wires and look for obvious damage to the boards. You should also find a sticker affixed to the panel. That would be the panel number etc. Do an online search with that and see if you locate a replacement panel.