Hi. I've have had a Sony STR-DE685 receiver for two years now. Just the other day the center channel and subwoofer went out for no apparent reason. No matter what component I use (DVD, CD, etc) there is still no sound. I connected the center speaker to one of the front channels and the speaker worked fine, so the problem seems to lie in the receiver. I made sure all connections were secure (speaker wire, input cables, etc), checked all the settings (powered subwoofer set to "yes", center speaker level set correctly) and the center speaker and subwoofer still do not respond. Even when I use the "Test Tone" function, the center speaker and sub woofer do not produce any sound. Any possible solutions are greatly appreciated.