Issue with Pioneer VSX-32?

[mostlyharmless]

I'm wondering if my receiver has somehow managed to fry its DSP chip? I currently have a VSX-32 which has the front 3 channels run into an adcom 6000 amp, the middle and rear channels are running off of the VSX.

Here's the problem, a few days ago, the mid and rear channels quit working. I thought the sound suddenly sounded very anemic, and quickly realized I had no sound coming from the back 4 speakers. At first I thought perhaps the amplifier had fried, seeing as I had sound from the front 3 separately amped speakers. Then I started messing with some of the sound settings. Unfortunately, all settings except extended stereo result in dead back and mid channels, but when I set it to extended stereo, suddenly I have sound coming out of all 7 speakers. Can anyone take a guess as to what happened to my beloved AVR? Is this something worth getting fixed? Or should I just start looking for a replacement?