1) Torex #7 (t-7) screw driver
2) Small Phillips screw driver
Step 2: Remove backup battery cover
Taking out the backup battery will clear your system RAM, which means that all of your saved programs will be gone.
Step 4: Remove 4 rear screws.
Now that you have removed the rear cover you should see a foil backing over the main circuit board, to remove this you will have to first remove the 2 screws marked below.
Step 5: Remove circuit board.
After removing the last 4 screws the circuit board should be loose, lift up on it carefully to avoid flinging keys everywhere (sometimes the keypad will stick to the circuit board).