Nothing works on my Pioneer VSX820 from my Pioneer remote model AXD7583. I have tried a lot of things even resetting the main unit. I cannot turn the unit on/off, cannot change volume and sources like DVD, BD, etc. I was told that I need to unlock the unit with the set up code, but how do I do that? Cannot find anything online including procedure how to do that. Could someone please help, I'm desperate? Thanks for all the help.