1. Shut down your Alesis and disconnect power

2. Carefully open the cover of your Alesis to expose the circuit board.

3. Find chip "U19" as shown in the pictures.  This is the chip you need to swap.  Yours may look like the one in the pictures or it may have a sticker on it.  Be sure to note the orientation of the notch on the chip.  

4. Pull the chip straight out with the chip puller tool ensuring not to bend any pins.

5. Install the new chip in the same slot ensuring you have the notch pointing in the same direction.  

    Note - You may need to carefully bend the chip legs slightly to align them with the socket holes.

6. Reinstall the cover, power up, and enjoy

There is also a walkthrough video of the process on Youtube if you need more info.