Avera TV fades to black after turned on

@cayce00 this "Sometimes I see shapes and shadows" alone, is pretty indicative of failed backlight strips. Yes, it is possible that this is a power board issue on the backlight circuit, but unlikely. You can, and probably should measure the voltage output on the power board LED connector and see what you get. To replace the LED strips, you will have to disassemble your TV and the panel. Not to bad of a job, just take your time and do not flex the LCD panel. It will be thin and will love to flex, make sure it is stable when you remove it. If you get stuck on anything, you can always post images of it with your question. That way we can see what you see and hopefully guide you a bit. Adding images to an existing question

Since your TV is a bit off-brand we do not have any guides for it. It would be great if you take lots of pictures and create a new guide for it. that way, should anybody have issues with their TV, they will have the help they need to fix it. The community will be thankful. https://www.ifixit.com/Guide/new