Please help a frustrated new owner of PX-5S. I am using stage setting 7-7 Polysynth. If I turn knob 4 which is release in this case, I cannot get the sound back to where i started and the sound becomes unusable.The only solution is to hit stage setting 7-7 to reset. I have found this with many other stage settings when turning knobs or moving sliders.The same happens with slider 1 in stage setting 0-0. Any advice would be appreciated. Thanks.