Chosen Solution
One day, I turned on my DSi and the top screen was faded with what looks like interlacing artifacts always going down the screen. Today, I took it apart, cleaned all of the contacts with 70% isopropyl alcohol and I noticed that the screen works completely fine without the shoulder buttons and SD Card slot (back panel) connected. However, when I plug the back panel back in, the problem appears again. I don’t have a lot of knowledge when it comes to electronics so I decided to come here to ask how to fix it. Thanks!
Hello, I had the same problem today and discovered, that there are some kind of potentiometers, wich are regulating the screens in some kind. However, you find them if you look on top of the battery. There are two little screws that you can turn to calibrate the screen. The left one is for the lower screen, the right one for the upper screen.
Sorry for my bad english but I hope that this could help you.
I thought those were screws and broke the right one by accident .. is there anything I can do about it?