Removing the power supply from the iMac G5 is a two step process. First, see where the power supply is located. Then begin the process of removing it. You can do using a very easy way described in this video. First unscrew the 4 torx screws that are located around the edges of the power supply. Be careful not to be too rough while doing so. Once you have unscrewed them, then gently lift or remove the power supply. However, we still have to unplug it from the iMac. Therefore, carefully unplug it's connecting cable from the iMac, and you're done.