Onkyo Receiver Thermal issues

Can't. Not your fault. If the solder joints were built weak (a manufacturing defect) they can fail eventually. The "thermal cycling" they mentioned is going to happen to every product as it's used (turned on and off). Doesn't sound like it was your environment - just bad luck. Do make sure the receiver has ample ventilation, and that air can move around it to keep it from getting too hot.

Sounds like you did get lucky on the warranty coverage at least. Probably won't happen again. Something else will fail instead.

Jeff

This is a relatively common problem on Onkyos (so I've heard, HD Guys podcast and other sources), I had the 607 model but always have used an A/V rack made of perforated metal, specifically it was an older Bell O'getti stand that happened to look nice and had perforated metal shelves. Also if I have any components that don't have more than 1/8" clearance from the bottom of shelf due to having small "feet" I will put thicker bumpers on them to raise them to 1/3"-1/2" off the bottom of shelf.

I'm really anal about temps having lost some good equipment over the years but ever since I've been doing an open, perforated shelf rack design, and raising the feet on low clearance components, I've had zero problems.

If you have a Laser IR temp gun, aim it inside your Onkyo sometime when it's running, you'll see how hot it gets above room temp. I also have used some wireless Honeywell temp sensors that you can put in a few places amongst your rack and they report back to a bigger LCD screen (about $50 on AMZN, handy for lots of things. . .) and you can keep track on the ambient air temp, but remember the internals will always be much warmer.

Hope this helps, let us know. . .and congrats on getting Onkyo to foot the bill, that's good to know they stand by the customer like that.

I have run an IR temp sensor on both my 605 and 806. They tend to run 80-85 deg-F. However, I have also heard the stories, so I keep my units well ventilated. Nothing on top and good clearances on sides.

I think the stories are exagerated, and probably caused by people putting these things in tightly enclosed cabinets. The Onkyo units definitely need room to breathe, but if you do that, you can expect years of good service. My 605 is now close to 5 years and going strong daily.

As for the cracking solder joints, it isn't uncommon. Wave solder is tricky and bad joints happen all the time.

Also an Onkyo AVR owner. I added a fan with a temperature sensor to help with the heat dissipation and it makes a noticeable difference. The fan's speed increases as the heat does and even at full rpm the noise is undetectable. Without it, after watching a bluray with True HD or DTS-HD sound, the top of the AVR was so hot that I thought something was wrong with it at first. But come to find out that is normal for Onkyo. I figured it certainly wouldn't hurt though to add a fan to help keep it cooler. With the fan in place it was barely warm. Not saying it would've prevented your particular issue internally but just another option that's out there to consider.

Something similar to this:
http://www.coolerguys.com/comcool.html