Hi i just recently bought a new sound system and I am using a yamaha htr-5750 and im a little confused, for the display screen before today i had my left, right, and sub showing, today i just have my left and right, even though my center and subwoofer are hooked up, my subwoofer still works but is not displayed as plugged in, i have gone through the setup like i first did but when doing that it shows it as dim just like the center channel and i have no idea what to do to show my subwoofer back up on the display showing it is working.