I have a PR-SC5508 which also recently suffered an HDMI board failure (after ~16 months of use).
I spent weeks trying to get Onkyo to send me a box and a shipping label: first I tried contacting Onkyo by phone, and couldn't get through--there were long waits (funny how the recording always said there was "unusual call volume"). I tried posting in their support forum, and they asked me to send email. I emailed their customer service address (firstname.lastname@example.org), but had a hard time getting all my questions addressed. I even tried escalating to a supervisor, but when I tried emailing her I got an automated reply saying she was out of the office for 2 weeks! I finally got hold of another supervisor and got the return process started.
The 5508 sat at the regional service center waiting for an HDMI board for a little over a month. It just arrived on Monday, and the unit was repaired, and is currently in transit back to me. I hope the repair was done well and this chapter is behind me; Onkyo says their HDMI board was redesigned and I really hope the unit is reliable from this point forward. I understand design and engineering failures can occur and that HDMI board failures have affected multiple manufacturers over the past several model years, and I even acknowledge that we don't know the prevalence of these issues (lots of Onkyo failures reported on this board, but they also ship a lot of units). But: given the experience I've had so far, I really question the quality of Onkyo's customer service, and commitment to their users: they never once apologized for building defective products , for making it near impossible to get through to them for warranty service, for taking weeks to answer my questions and giving me the runaround, and for being out of stock on the necessary part for over a month.
This all serves to make me question whether they will stand behind this product down the road. Suffice to say, I will never purchase an Onkyo product again.
 my previous 5508 died in less than 30 days of use with the IDE cable/listening mode issue despite Onkyo customer service's assurance that my unit was not in the affected serial number range.
Edited by js19707 - 6/5/13 at 10:51pm