How do I replace the Black Midframe on the 3ds XL?

This is a pretty difficult replacement, since it involves opening up both halves of the system.

This is a video on how to fix a cracked hinge by replacing the midframe: https://www.youtube.com/watch?v=dVn_m_OI...

I'd give it a quick watch before deciding whether or not to replace it.

Assuming that you are a beginner to this sort of thing, the risks to damaging your system are pretty high.

(I did this to fix a cracked hinge, and regret not being more careful, as my circle pad no longer works. But now I have an excuse to buy a New 3ds, so I suppose it's not all bad.)

Most steps to the process are in this guide: Sostituzione touchscreen Nintendo 3DS XL

However, in order to re-attach the top screen, you will have to remove its outer shell, as shown in this guide:

Sostituzione schermo LCD superiore Nintendo 3DS XL

From there, just follow the first video, taking care to not damage the wires. These can be slid through a slit in the casing by the hinge.

The main things to watch out for are

- Don't strip any screws. If the screw isn't coming out, try a different screwdriver. Magnetic screwdrivers are pretty helpful here.

- Do not break any of the grey flaps on the motherboard. From what I can tell, these can only be fixed by replacing the entire motherboard, which is one of the more-expensive parts.