Malfunctioning Pioneer XC-IS21t (by 3 users)

Hello,
I have a Pioneer XC-IS21T and haven't used it for a few years. I went to use it yesterday and in does not work. Everything seems to be working properly, but there is no power to the speakers. This unit has a separate amp with a gauge that monitors the power. All the lights turn on, the cd spins, the tape deck operates, the speakers just don't speak. They don't even make a hiss. I know the speakers are ok because I hooked a battery to them and they made noise. The problem seems to be in the amp. When I turn the volume dial, the needle on the gauge doesn't move. The amp makes a clicking sound every time I hit a button on the main unit. It might be a problem with the power switching(?). I took it all apart and could find nothing. There was a small circuit board laying loose that may be the culprit. It only has 2 small contact points on it but doesn't seem to attach to anything. It is labeled "AWU7349" and "NE M PF2" and "BIND ASS'Y".
Sorry for the long description. Can anyone help?