This is a short guide on how to overclock the TI-89 (Hardware Revision 2)
Begin by removing the batteries from the calculator. BE WARNED, all data in ram will be lost!
Remove the back screws (torx bits) and remove the back using a plastic spudger.
Remove the RF sheild by taking out the two philips screws (near the bottom).
You'll need to remove C4 from the calculator, and then replace it with another capacitor. Don't go anthing under 22pF for your replacement capacitor.
This is my replacement, which isn't fantasticly done. Please take care when you're replacing the capacitor, as being prescise in this instance, is incredibly difficult.