It is funny how things work out. In the WASAPI Sound settings in Windows 10 you can enable Stereo, 5.1, 7.1, Dolby Atmos, and some interesting headphone options which only work if you headphones are plugged directly into your computer. If there is no surround encoding detected in playback from the PC My Yamaha shows all speakers active except the center channel speaker. I have Blu-ray stuff with very loud atom bomb level ka-booms. What I noticed is I have never had the Yamaha shut down with a “check speaker wire” error on restart. With this in mind I went into the Yamaha’s settings and disabled my center channel speaker and started playing “Jupiter Ascending”, Man of Steel, and the Marvel movie at high volume levels. Not one shut down. There is some issue with my center channel speaker. The funny thing is it sounds better without this speaker, a Polk Audio AM1582-A CS1 Series II. I have been trying to track down a service manual for this RX-A770. Like so many other companies Yamaha is not releasing it to the public. I understand there is a key sequence on startup that puts this AVR into a diagnostic mode. There if you have a check speaker shutdown it will tell you which speaker.