I just had a second hand STR-DN1000 and speakers delivered. On plugging in the amp there's a slight noise inside the amp indicating something is getting power (relay?) but no lights on the display. I have had a look inside and can't see anything dislodged in transit and the 3 fuses look OK I am missing something blindingly obvious to get it to come on/show a display (I'm pretty much a home theatre virgin so it's quite possible)? If not, what could have got damaged in transit?