I recently returned from vacation, and much to my dismay, my rear-right channel is not working! I know it's not the speaker, because if I change the wiring around (say, put the rear-right speaker cable in the rear-left output), I get sound out of the speaker. Nobody said anything to me about anything happening to my receiver while I was gone, so I'm expecting equipment failure Is there any common explanation as to why a single channel would suddenly not work? Also, if it is equipment failure, is it repairable? How much would it cost me? I'm running the RCA RT2250 receiver with the RCA RT2250 surrounds, by the way... Thanks in advance!