There are four screws on the back of the iAudio X5. Remove those screws. Take off the back cover, and you see the hard drive. There's a gray T-shaped piece of tape connecting the hard drive to the headphone board -- remove this tape, being careful to not break the wires, and lift the top of the hard drive out. Pull the connector _straight_ out of it and remove the hard drive. The battery is the green-covered piece directly underneath. It is connected by two wires to the lower left corner, red and black -- do not mistake the battery connector for the microphone. Unsolder these wires and solder the wires of a new battery into place. Reassemble, and you're done.
DrkShadow, December 2007
