I didn't see an Instructable about how to replace the DS shell so I decided I'd write one up. It's a pretty complicated process and took me about 3 hours to complete, so I figured that a lot of pictures and descriptions of the process would help others. I labeled each section to make it easier to find a specific part of the process.
You WILL need a tri-wing screwdriver for the replacement so either get one off of ebay or if you place an order with dealextreme.com, add one to your order. You will also need a small phillip's head screwdriver, a flathead screwdriver, an exacto knife, a soldering iron, some de-soldering braid or solder sucker, and possibly some needle nose pliers.
When taking your DS apart, pay attention to how everything fits. Don't just rip it apart, take notes if you need to. It really helps in the end. When you put the DS back together, the hole will probably not be threaded so it may take some force to get them in there.
Step 1: Disassembly: Part 1
The first step is to unscrew the battery cover and remove the rechargeable battery. Also, make sure to take out your GBA cartridge, stylus, and DS cartridge if they are in the DS.
Next, you will use your tri-wing screwdriver and a small phillip's head screwdriver to remove all of the screws. on the back. The blue squares are screws that are covered by little square rubber feet. You can use a small flathead screwdriver or an exacto knife to remove the covers so you can get to the screws. Also, don't forget the little black screw in the DS cartridge slot.
After all of the screws are out, you can SLOWLY pull off the back cover. You want to be careful to hold the shoulder buttons when you take this cover off because they are spring loaded and will go flying if you're not careful. My replacement shell came with some extra hardware such as screws and pins but it did not come with the springs for the shoulder buttons. Pay attention to how the shoulder buttons are placed!!!
Step 2: Disassembly: Part 2
Now that we have the bottom cover off, we can start to disassemble the top. The screws for the top are hidden under these little covers. I would highly recommend using an exacto knife to get these off. I tried using a small flathead screwdriver and it's pretty tough.
Once you have all of the screws out, hold the top portion of the DS with your thumbs in front and fingers in the back. Push down with your thumbs and up with your fingers to slide the back cover of the top up. I had to use a small flathead screwdriver to pop it off once the cover was up.
Disconnecting Wires from the Top
Now that the back cover is off, the first connection to the main circuit board can be disconnected. This part is tricky and will require a soldering iron, some de-soldering braid or solder sucker, and some patience. To make things easier and secure, I flip the wifi board and stick it right back onto the pegs that it comes off of, exposing the wire that needs de-soldered. Using de-soldering braid or a solder sucker, de-solder the wifi antenna wire. After the wire is disconnected, pull it through the hinge and place the board somewhere safe!
Now, the microphone will need to come out. First, unhook it from the main circuit board. Then, carefully pull it through the hinge and pull the actual microphone out of the plastic case.
Once you have the back of the top portion off, the wifi board de-soldered, and the microphone disconnected, I like to tape down the speakers and the screen. We need to go back to the bottom portion to unhook all of the connections from the top and if you don't secure the speakers and screen, they may fall out and get in the way.
Step 3: Disassembly: Part 3
Now that most of the connections in the top portion of the DS, the main circuit board can be unscrewed and the top screen can be disconnected. after taking out the one screw in the main circuit board, carefully flip the board up to expose the top LCD screen connector. All of the plastic pieces to the buttons as well as the rubber pads will be loose so make sure not to misplace them. Using a small flathead screwdriver or a exacto knife, lift up the black part of the connector, it should flip up and the ribbon cable should slide out easily. Once the ribbon cable is disconnected, the main circuit board is free and can be placed off to the side.
Disassembling the Hinges
To disassemble the hinge, the indicator light will need to be unscrewed. There are two screws that keep this piece in place. Once the indicator light is removed, make sure to pop out the translucent piece inside of it. My replacement kit did not come with this and I didn't realize I was missing it until I had finished assembling the whole DS back together....
Once the indicator light is unscrewed, the top portion of the DS can be disconnected from the bottom portion. Slide the top of the screen to the right. Once the top portion is disconnected, the LCD cable can be fed through the hinge. I rolled mine up and stuck it through.
There are two parts to the hinge mechanism. The bigger part is the thing that clicks and locks the screen in position. The other piece is just a metal coupling. The larger part may need to be pulled out with some needle nose pliers. Make sure to remove both. The only thing left to do is pop out the screen. The screen is stuck in there pretty well so take your time, you don't want to crack your screen and have to wait two weeks for a replacement. Apply slow, even pressure to the different sides. My replacement shell also came with a replacement screen protector for the top screen. If you want to replace yours, use an exacto knife to slowly pry it up.
Step 4: Assembly: Part 1
I started off the assembly process with fitting a new screen protector on my top screen. If you decided not to replace yours, you can skip this step. To get the fit right, I first put the screen in the top portion. I then placed the screen protector through the front to make sure the placement was correct. You can also replace the plastic boarder around the touch screen but since mine was the same color as the new one, I left it.
Placing the Speaker in
After the screen protector is in the correct position, you can place the speaker gaskets and speakers back in. I used some scotch tap when putting these back in as well. Make sure to tuck the wires in the groove below the screen. If the wires are sticking out, you will have difficulty putting the back of the top portion on.
Threading the LCD Ribbon Cable and Connecting the Hinge
Next, put the metal hinge coupling in place, roll up the LCD ribbon cable, and push it through. Now take the top of the bottom portion of your DS, the one that the buttons stick up through, and fit the cable through the slit and slide it into the top portion.
After the two pieces are together, the clicking hinge is placed in the top portion and the indicator light is screwed in place. Since I forgot to put the translucent piece in the indicator light, it is not shown in the picture. I placed the button pads in next, and connected the LCD ribbon cable to the main circuit board.
Connecting the Wifi and Microphone
Next, you can feed the microphone cable and the wifi antenna back through the hinge. In my picture, I placed the mic antenna over the DS game slot but it should be fed underneath the main circuit board. Make sure to tuck the microphone and speaker wires down in the groove. I taped this as well because I found that the wires liked to pop out.
Now, the wifi wire can be soldered back in place. I taped it down to the back of the screen to keep it steady. Make sure you solder the tip of the wire and the base and do not make a connection between the two. If there's a connection, it will not make the correct connection with the antenna. Place the wifi back in the correct orientation and tape it down.
Placing the Back of the Top Portion On
Once all of the wires are fed through the hinge and everything is in place, you can place the back cover of the top portion. Place the back of the top portion in the up position and put your top screen bumpers in place. A flathead is helpful to position the bumpers. Also, I used the old bumpers since they were the same color and had their adhesive still on them. The new ones did not have any adhesive but could be used with some double sided tape. Next, put the DS in the closed position and take off all the taped parts. Slide the back of the top portion into place, making sure all of the hooks catch on the top and sides and the screen bumpers are still in position. Also make sure no wires are being pinched. Screw the back into place and stick the square screw covers on. My screw covers didn't have any adhesive so I needed to use some double sided tape.
After the wires are all in place and the back is secured, the A, B, X, Y,Start, Select, and D-pad buttons can be placed in the housing and the main circuit board can be screwed down.
Next, the shoulder buttons have to be put in place. The metal pins and those small spring levers are used. The picture came out a bit blurry but you can kind of see how they are placed. The spring goes in the middle of the shoulder button, with the metal pin feeding through it. That is placed in the hole in the DS housing. The button is perpendicular to the the housing. The one edge of the spring is stopped by the shoulder button itself and the other end is stopped by the housing. Pushing the button towards it's regular position will compress it. Make sure the pin is pressed all the way down. The shoulder button should catch on the case and stay in place. It's hard to explain the exact process but hopefully you paid attention when you were taking the DS apart.
Placing the Back of the Bottom Portion
The only thing left is to place the bottom of the DS on. You will need to place the plastic power switch and the volume switch into the housing before placing the back cover on. Be very careful with the shoulder buttons, they come loose easily since they are spring loaded. Make sure your volume switch and the plastic volume switch are in the same relative position. The power switch is in the down position so make sure the plastic power switch is also in the bottom position. Screw it in place, and you're in business!
Step 5: Finishing Touches
I hope this instructable helps everyone trying to replace their housing! If you go through the process and find anything I missed, let me know and I can add it in! Take your time and good luck!