I was using my Denon AVR1803 amp yesterday with no problems, it was left on standby over night and now it won't switch on! Every time I try to turn it on it just switches to standby and the led flashes. Is my amp dead?? The manual says to turn it off for a while, so I unplugged it for about 4 hours and turned it back on, but the same thing happened again. Please help!!!!