Vizio model e550i-b2, has backlight and sound but no picture

I have a Vizio model e550i-b2 that someone was throwing away, it has a backlight but no picture. Sound is coming through the speakers as well. The lights sort of change brightness (minuscule amounts) in different areas when playing a movie, showing that it is processing a signal but there's no video being put up. I have done the common solder joint fix on the power supply and the middle board, and this was not the problem.

Any help would be great. Thanks!