Top screen has lines and is faded

You cannot really fix this problem, the only thing that you can do is replace the top screen. If it was dropped the screen was probably smashed (inside LCD) and there is nothing you can do other than replace it.

Sorry for the inconvenience.

The top LCD is not a great DIY project unless you're used to handling small ribbon cables. If you aren't careful, you'll tear the new ribbon as you're installing it. New LCDs are $10-$20 on ebay. Good luck.

i have the same problem!!!!! don't want to send on it in or replace

Yeah one day i decided i wanted to play on my Dsi XL and I struggled to pick it up from my desk and when i finally got it i opened it and the top screen was like halfway blacked out and random color lines were on it too i have know idea how to fix it plus its not even mine

have heard that the ribbons can be replaced but it needs specialized equipment like Z axis tape (this is for the lines only/blank problem, and a subset of those) but the glass is normally the cause.

I have a very expensive camera here with this fault, internal cable went bad but its a special sort of tape more expensive than standard Z axis as used in ipad repairs, chibitronics kits etc.

This works fine if the alignment is spot on for relatively large pitch connectors however like calculator panels!

If you have a good ribbon and screen then try https://www.adafruit.com/product/1656 might do the trick but alignment needs to be finer than a human hair.

Best done under a microscope or better still screen+camera.