Since signal doesn't go anywhere it's very likely your screen is fine and the issue comes from the logic board side. Anything unusual happened to the Mac ? The A1534 Macbook is a very strange beast, very compact and pretty difficult to work on indeed, one of the Macs with lowest repairability score of 1/10 !!
If Apple's goal is to keep people out from their Macs, with this they've really excelled. Given the kind of fault and the difficulty involved in this case I'd really discourage anyone without a strong technical background from trying anything on a DIY basis. Although probably useless try resetting PRAM and SMC, just in case it's a low level software issue.
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