Yamaha RX 765 Receiver Zone 2 Intermittent

I can turn on system and select zone 2 but nothing happens. Sometimes, can unplug Yamaha and plug back in and Zone 2 works and will work for as long as system is on. Then, when system shut down, MAYBE zone 2 will work but most often not. Then I unplug Yamaha for a few minutes and it may come back on with zone 2 working. If not, I unplug and leave unplugged a while longer then when stat up again, zone 2 might work. Is this a power supply problem? Is there a circuit breaker somewhere of which I am not aware? I bought from Crutchfield. they said could be short in speaker wires or Niles controller. I have put speakers on short wires directly to zone 2 connections and get same thing. I have then introduced Niles controller into setup, exactly same thing. I can tell when it is not working because I have Niles unit out of wall receptacle so that I can observe what's going on and when it works, I can feel it in the Niles unit and can hear Zone 2 speakers. If it is not working, no feel in Niles, no sound at zone 2. When it is working, I have noticed that when I select my Bluray (for Pandora or dvd) or select TV, the main volume starts out really loud and I have to immediately turn it down. However, I have come to recognize when I turn system on and main volume is okay, I know zone 2 will not be working. It does not matter if I leave Zone 2 on or off when shutting system down and turning back on.
Thanks in advance for responses.