That looks like something is physically blocking the image. I would take off one or both of the side portholes and inspect the inside of the tv with a flashlight.
The edges of the back big mirror have tape on them. The edges of the plastic screens has tape on them as well. There's some kind of gasketing between the light engine and the top cavity to keep stray light out of the top half of the tv. The adhesives on all of that stuff rots over time and can come loose. Look at the inside bottom of the front screen, the bottom of the main mirror, and the area around the main lens.
There are also some wire harnesses in there that could have come loose. Clean the porthole covers while you are at it, they act as air filters.