Before replacement, i suggest opening your macbook up, unplugging and plugging back in the display cable. If it still has the issue, you need to get a new screen
[guide|17045]
There is the guide to replace the screen. To check the cable, do up to step 4 and then skip down to step 11 to remove the cable. Dont remove anything else but the battery cable and this cable.
[product|IF117-010]
That is the part. Ifixit doesn't have new ones but grade A is basically like new. If you dont care about a few minor scratches on the metal lid, the grade B is 50 dollars cheaper and still a good buy.
Another option is to get one of these macbooks used on ebay with a good screen for less that the money is to buy the screen. That way you get the screen and some other parts that you can sell and make some money in the process.
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