I bought the TX-SR605 2 years ago. It worked fine for a couple of months, then the problems started. They were intermittend so I tried to live with it. I just wanted to avoid the hassle with shipping it to the service. My receiver goes into protection mode (red LED blinking). I've noticed that the protection mode is triggered by vibrations, for example whenever I bump into a TV stand or just close its door. Sometimes a more powerful sound can trigger it, though it is not consistent. When it happens I just turn it back on, and it again goes into protection mode, but after a couple of tries it works again. Sometimes I just hit it on the top and it seems to help (???!!!). I tried to narrow down the possible causes. When I disconnect all speakers the receiver works fine even with volume maxed out. I reconnected all speakers one after another and found out that the culprit is center channel input. This is not the faulty speaker, though. It doesn't matter what speaker I try to connect to center channel posts it immediately trips off. The wired thing is that sometimes it works fine. I am in loss. Guys, if you have any ideas, I would appreciate it. I got tired with constant battle with the unit so I disabled center channel in the settings. I know it sucks. Shipping it for servicing is probably not worth the cost. I love Onkyo when it works, but with my experience I am a little affraid to fork out $$$ for a new unit.