Hi, hoping someone can help here. Just bought this receiver. I plugged all the speakers (4 of them) in correctly (I think -- I followed the instructions). However, I can't get all 4 speakers to work properly. When I select "stereo" as the surround mode, one set of speakers works fine, but the other set doesn't work at all. When I select a different surround mode (any different mode -- Pro Logic, etc.), all 4 speakers will play, but only very quietly and with a very loud hissing. I only tested this trying to play FM radio thru the built in tuner (yes, I was getting good reception, because it's very clear and crisp when I select "stereo" as the surround mode -- but only 2 speakers will play).