Here we have a tutorial which shows how to take your PS3 apart.
WARNING – Doing this will void your warranty, there is a risk of electric shock, never attempt this while the unit is plugged in, and allow time for capacitors to discharge after the unit has been powered on. PERFORM THIS PROCEEDURE AT YOUR OWN RISK.
Beware
There are many guides online for the dis-assembly of the PS3. However, the majority of these websites have been developed and posted by amateurs, not by professionals that have been trained and actually do this for a living. For example, one online guide fails to mention that you will need heatsink compound to put the PS3 together again, also they use a polystyrene packing sheet to do the work on! This material can be highly charged with static, and potentially ruin the PS3 completely!
First Things First!
Before you start, make sure you have a small tube of heatsink paste. You will need this to re-attach the heatsink when you put the PS3 back together.
On the left you will see the type of paste we use at our shop for the PS3 Processors. Failure to ensure proper thermal conduction to the processor heatsink and fan assembly will result in an early death for your PS3.
Now we have that out of the way, you will need a few other tools. A set of small precision screwdrivers always come in handy. You will need a TORX screwdriver, and a philips screwdriver.
Lets Begin
So, get your PS3, and look on the left hand side of the console.
Under the warranty sticker is the cover as shown by the arrow. Remove this cover, then use your TORX screwdriver to remove the screw. When the screw is removed, you can slide the top cover to the left, and lift it off.
So, with the top cover removed you should be left with what we have in the picture below. There are now 7 screws to remove. Sony have been very helpful here by putting arrows that are molded into the plastic casing of the PS3, not for our benefit, just to help the people that assemble the PS3 units in factories 
Use your philips screwdriver to remove the 7 screws from the PS3. Please remember their location. One trick I use is to lay them out in a tray, in the same location as where they came from on the PS3. So, in my rectangular tray, I put the screw from the top left corner of the PS3 into the top left corner of the tray, top center screw from the PS3 – top center of the tray, and so on…
Once all of the screws are removed, lift the back of the PS3 console gently, so that it ‘hinges’ up at the front.
STOP!!!
Do not try to remove the top cover completely, just yet. With the top hinged up like this, take a peek inside. Yes, that’s right, there is a cable connecting the top of the PS3 to the mainboard. This cable can be fairly fragile, and easily broken should you lift the top quickly. On the pictures below, you will see that there is a connector in the top part of the PS3. This is known as a ZIF connector (Zero Insertion Force). Next step is to disconnect this. There is a brown part, flap, that lifts. This removes the pressure on the end of the cable, and allows you to remove it.
The last picture shows that the flap for the ZIF connector has been lifted. Use a small flat head screwdriver from your precision set to do this.
Once the flap has been lifted the cable will come out easily. Remember this step, as you will need to perform this in reverse when putting your console back together.
There is also a ZIF socket on the mainbaord. So you can remove the cable at either end. However, we have chosen this way for our guide, as the other end is somewhat harder to get to.
Now, you should end up with what we have in the picture below. The arrows indicate the next 5 screws to remove with your philips screwdriver.
Once you have removed the 5 screws, you will need to disconnect 2 cables. One at the front, and one at the back.
With these 2 cables removed, lift the Power Supply off and put in a safe place. Next we move onto the BlueRay drive. At this point the drive is not secured by screws to the PS3. There are 2 cables though, which need to be removed. The first is located toward the front of the drive on the left hand side.
Pull the connector out of the socket on the PS3 mainboard gently. Once this is removed you can lift the drive up slowly. Under the drive you will notice a wide silver ribbon cable. Again, this is secured by ZIF sockets. Using a small flat head screwdriver from your precision set, gently lift the flap of the ZIF socket. Once the flap lifts, you can remove the ribbon cable from the socket.
Now you should be left with something like the picture below.
Remove the screw that secures the yellow/green grounding wire to the chassis. Next locate all of the screws that hold the thing down. Again, Sony have marked their location with arrow stamps into the metal
You will also need to remove the Bluetooth and Power/Reset boards while your at it.
Remove all of the screws to enable removal of the above 3 circuit boards. If you have not already done so, remove the HDD cover from the side of the console, and then remove the Hard Drive. Put both safe.
Now we have to remove the 4 screws that hold the heatsink to the mainboard. Refer to the picture to the left.
When you remove the 4 screws, the clamps will spring up. Remove these and keep safe.
Next, we will flip the PS3 over.
Gently lift away the plastic casing to reveal the picture on the right. Next, unplug the fan from the mainboard, remove the plastic grill and power block, then lift away the heatsink unit. There is thermal paste on the heatsink, which will cause a little resistance when lifting away.
Next remove the 2 screws holding the metal shielding at the Hard Drive point to the connector, which connects to the mainboard.
Once these screws are out, you can completely lift away the shielding, and you will be left with the exposed mainboard.
To re-assemble, simply follow instructions in reverse.
