My KENWOOD kra5080 that I have left on for years. I heard a rapid clicking sound when not in use. There was no display. I turned by CD player only to hear constant clicking from my amp. The on/off button didn’t work. I unplugged the AC several times still no response. So connected the AC and started doing something else. I noticed the clicking seem to subside and gradually stopped. I returned and saw the display screen on and I was able to play my CD .