I have an NAD 320 BEE amp that has mysteriously stopped working, 'just like that'. When you turn it on now, you get the standby light on, and when, as I would usually do, you select the appropriate source to trigger the amp 'on', absolutely nothing happens. Before, the amp would select the source and turn on, change to a green light etc. But now, nothing. Anyone any ideas? Any sort of 'reset' anyone knows of? Cheers in advance.