It is a very common faulty in onkyo av-amp.
If your amp was bought before 2012 3/4 quarter, no matter how carefully used, it gives you no sound. There is a very useful way to make a complete diagnosis via service mode. If you want to DIY, leave your email here or in my message box.
I don"t tell you here. Why? I buy faulty amp to fix on web and sell them out.