Thanks very much for this. After two different electronic repair shops had refused to replace the broken top screen in the 3DS which our daughter had borrowed from a friend, I reluctantly decided try it myself, having studied this guide a couple of times.
It took me over 4 hours, almost an hour of which was just getting the 3 ribbon cables out through the hinge and back in again. It was incredibly satisfying to power it up again and have everything work. Without this detailed guide and photographs, I would certainly have given up.
Use good quality screwdrivers!