Horizontal lines and darkness on half of screen

I have a quite old LE55FHDF3300Z and half of the screen is dark, with horizontal lines across it. The image also take a long time to refresh on that half of the screen, leading to a jumbled ghosty mess, all of which makes me pretty sure it's not just a backlight issue.

I left it unplugged for a while and discharged the capacitors by hand just in case but no luck. I can't see any obvious failures on any of the boards (though, I suspect the control board would be the problem here if any of them are faulty). Tragically don't have access to a multimeter to check the boards. I took each board off and checked underneath for any signs of damage but they look fine.