TCL Half of screen darker

Sherri B  it is possible that this is an LED backlight array issue. Post some images of what your screen shows. Use this guide iFixitでの質問に画像を追加する方法 for that. You also want to try to reset it. Remove all input sources as well as soundboard etc. Then unplug the TV. Either hold the power button down for a few minutes or keep the set unplugged for something like 30 min. Then connect only one video source ( a local source like DVD/BR/ or Game console would work. Stay away from cable or sat box for now since they can actually be part of the problem).. Then plug the TV back in and see if that made a difference. If it did not you will have to remove the back cover from your TV and take a look at the board. Check for any obviously damaged looking parts and reseat the interconnect cables. Post some pictures of the boards as well. You will need a multimeter to check the LED connector voltages etc. TCL is still a bit of an off-brand make so there are not a whole lot of schematics etc. available so we need to rely on your images to see if we can find out what's going on.