@kfr97gjsi2d9ew0 number one thing, after a couple years of not having been turned on/charged would be a new battery. Yours will have to be discharged below the threshold of allowing it to be charged. After that you want to check the power conenctor and the fuses on your circuit board. For that, you will have to take it apart. Use these guides for that Nintendo 3DS XL
Take a look at your board and see if you find any damaged looking component, torn ribbon cable or anything else that might look different. You can always post a couple of pictures of what you find , with your QUESTION. That way we can see what you see.
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