You could also shine a light into the middle of the screen and look for the blinking folder icon, that would indicate the backlight is not working. If it is an MC207 model, it is a LED-backlit screen and will need to replace the whole screen.
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== Update ==
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As I understand it that is a problem with the GPU and reballing the solder underneath will fix it. There are plenty of repair places you can send it to for 100-125ish to fix it. This is not something that would be able to be done at home with normal tools. I have also seen a temporary fix of using a heat gun to attempt to resolder broken points, but its only a temporary fix when it does work, and most of the time it does not.
You could also shine a light into the middle of the screen and look for the blinking folder icon, that would indicate the backlight is not working. If it is an MC207 model, it is a LED-backlit screen and will need to replace the whole screen.