Sony Dav-sc8

I Have One Of These Units And A Few Problems With It. Will Not Come Out Of Standby And When It Does It Will Not Select The Dvd Input And Will Not Accept Discs. It Will Select All The Other Inputs And I Have Sound From All The Channels. Have Disconnected All The Supplies To The Dvd Deck Still The Same Problem. Any Ideas Out There Help Would Be Appreciated. I Thank You