Loose connection or faulty amp on Ford 6000CD stereo?

Hi,

My Ford puma has the factory fitted 6000CD stereo fitted. Recently it has been playing up and I thought it was a loose connection. One moment the sound is fine, then suddenly it looses the volume goes down. The volume controller is still set at the normal level, but the sound just drops off. I removed it from the dash, removed all the connections at the back and re-fitted it but it still plays up. It is really annoying, one moment it is fine, then suddenly it drops off.
Yesterday, when the stereo was turned on, you can here the amp kick in then suddenly it clicked again and the volume dropped off again. Does that mean the amp within the stereo is on its way out.

If anyone has any ideas, or has has this happen to them then I would like to hear from them.
Cheers