Is the LED backlight or driver has failed. There are youtubes on this (many make and models) but this work is not considered user serviceable. If you are an electronics tech, google youtubes to see what they do, if not, get repair estimates.
Always try installing the latest firmware and factory reset.
A dark shadow across the bottom half of the tv appeared several days ago. I saw others who had this problem and was wondering if it's repairable and at what cost. TV is 3 years old. You can see through it. Any help is greatly appreciated.

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