I was getting the dreaded audio sound cutting out symptoms, with my 3 month old tx nr 626. Sound cut out, got really loud, quiet, clicked, then after a while sounded normal, then randomly repeat, whenever I changed inputs, fast forwarded pvr, changed audio tracks, changed channels, changed pretty much anything except volume, and it also on its own from time to time. It happened whether or not I was using hdmi to provide sound or optical. I initially figured it was a heat problem, or hdmi board issue, since I only have 3.5 inches clearance above the receiver, and read about this online. It seemed like the receiver couldn't sort out what audio mode to use, it would kind of "lose" the audio setting, then take about 30 sec or so to figure it out, all the while clicking and the audio mode indicators turning on and off and switching from dolby to dts, etc. I started to guess it also could be firmware related, and didnt want to do a system reset. So after cycling on/off pvr/ps3/avr, etc i began to play with the avr settings. The setting that made it go back to normal was..... Turn off hdmi cec. Use receiver, noticed it's all good! Turn on hdmi cec. Still good. Maybe some kind of hdmi cec handshake problem - my tv is a 2010 pn50c550. I feel a bit lucky that this worked, and hope it sticks. Was close to calling onkyo for tech support. Hope this is useful for anyone that comes across this issue!