All right, I have an LG 55LS4500 that the screen just went blank on but you can still see the backlight on. We’ve had it for a couple years now. Doesn’t seem to be sound but we do have a sound bar by passing the tv speakers. But I do know that the back light is on and the main board is getting juice as I can see the optic cable light on and the power button responds. But no picture, so I took off the back and have theory it might be t-conn or maybe main board. Through some troubleshooting I’ve gotten the attached result when unplugging one side of the t-conn this happens, and if I switch it and plug it back in and unplug otherside the left side remains white but visible slightly vert lines and the right becomes dark but with power to it. But now when they are both plugged in the white left and grey? On the right. I plan on tomorrow attempting to test the hdmi ports with some device to see if there’s sound at all. Please help folks. Thanks Nick