When trying to charge a cellphone via the USB port on the amplifier, I blew a power resistor and the 5v regulator on the amp. The following images show the repair process:
Hey! This post was written a long time ago, but I'm leaving it up on the off-chance it may help someone. Proceed with caution. It may not be a good idea to blindly integrate this code or work into your project, but instead use it as a starting point.