You deserved better service support than this!! Anyway, that's why unless money is not remotely an issue or even a concern, I don't recommend anyone spending extra $ on such so called "separates" for HT multichannel applications. There are too many things to go wrong on be "buggy" (think those boutique brands Arcam, Anthem, even NADs, Emotiva when first launch, and some remain buggy for many months before a few FW updates).
And I have AVRs that are almost 20 years old, and working 100% fine just not on my racks anymore!
It is better to seriously consider AVR models that just got superseded by a new model, at deep discounts, and just use it with external amps. I know that makes even less sense and seems unthinkable for those who insist on not paying for features they don't use even if there are significant net savings if they go that route, but for many, why argue with money, if as example, an AVR-X3800H, even the X4800H would cost much less and have more useful features than an AV7706? Again, that doesn't apply to you, but to those on a tight budget and maybe money matters a lot more to them. It also doesn't apply to those who must have something that looks pleasing to them. My whole point, is an AVP or AVR that has 11 or more channel processing not counting multiple discrete subwoofer outputs have a lot more that can go wrong than those less than 10 years old models, and are often not practically repairable. I know you are one who would think AVRs are even worse, much worse because of the large numbers of power amps jammed into one box, but can't argue with the facts that they don't seem to be failing any more than AVPs, as power amps are usually trouble free if only used lightly, or on standby mode only all the time, like the preamp mode, or even just ECA mode.
PS- Good thing you anticipate the issue might return so you don't lose much uptime with the 7706 right there, and I am posting this just to remind others of seriously considering costs if they are sitting on the fence of choosing an AVR or AVP, and that the perceived advantages of the so called "separates" really don't add up to much in the case of the highly complicated AV devices that have channel count >>7.1 or that are the norms less than about 10 years ago.