@anthonyant16816 this "black/dark purplish display" should be your backlight. If unsure, either remove the back cover from your TV and see if your back lights are on. You will see those shine through some of the holes in the back cover over the display. Or in a darkened room, shine a flashlight beam at an angle at the screen. See if you can make out any shapes etc.
This sounds more like a panel issue. Post Some good pictures of all of your boards and let us see what you got going on there. Also, check the ribbon cables. Make sure they have no tears, bad contacts, corrosion etc. What does the fizzling look like and do you have any audio.