Hi;

We looked into your specific receiver at length to find out what might be causing the problem. First of all, as former Onkyo owners ourselves, we know that unless you have your unit at least as well ventilated as recommended (they recommend an 8" clearance on the top and sides of the unit for proper cooling) that it would shut off as indicated. You are also running exactly the same speakers that we were. That finished when we set the receiver out in open air well away from other equipment.

The manual also suggests that the second set of rear speakers need to be powered by a seperately sold two channel amp. We found that on page 21. You might want to look into that angle.

All of the above being said, we can manufacture an inline speaker box for you that will raise the impedance of all of the loudspeakers by two ohms. But we highly recommend getting proper ventillation to the Onkyo as the number one first step.