Returned due to HDMI/network issue
I too experience issues with lost audio on the TX NR818. Up to this point it has been rock solid. I updated the firmware to the latest just to be sure that wouldn't fix the issue. No dice. Unplugging the power cable for 10 minutes seemed to fix the issue for about two weeks but after that no amount of unplugging the power would fix it. Checked the network settings in the GUI and, sure enough, it was greyed out. After reading here about the bad network chip warranty return program, I headed over to Onkyo's site and filled out the form. Onkyo sent me out a box in a little over a week. I packed it real good and sent it back with the prepayed shipping sticker. They didn't even require a copy of the receipt. Tracking says that Onkyo revceived it and shipped it back in two days. I finally had a chance to open the box today and look inside. The HDMI board has the "NEW" sticker over the TI chip like other posters have described. I gotta say, the turnaround time is great. When my Denon Avr3311ci started having issues, I had to pay the return shipping for warranty repair and wait a few months for it to be fixed and returned.
I saved the Onkyo TX NR818 configuration to internal memory before I sent the unit in. There was a little note inside the return packaging that says the unit has been reset back to factory default. I take this to mean a microprocessor reset. I'm wondering if the configuration I saved to internal memory will still be there for reload so I don't have to find my microphone and do the Audyssey configuration again. With the Denon, I was able to save the configuration via the web interface to my laptop and reload it when it returned.