Onkyo srtx601 receiver. OK, still no surround sound - left, right, center speakers work. It's been

Question

OK, still no surround sound - left, right, center speakers work. It's been to Circuit City for possible IC problem, NO problems found by them - the got the surround left and right working fine. Think maybe simple set up feature - but need help - driving us crazy!!!!!!!!!!!No pink noise when level calibrated, etc. hookup is according to diagrams, etc. tv, dvd and cd players all work with subwoofer, front left, right and center speakers. again, think it's something in setup that we're not doing right. THANK YOU! PLEASE HELP!!!!!!!!!!!!