RCA Onkyo Ht-r510 Receiver 6.1 Channel Dolby Digital / Dts "subwoofer stay pushed" Questions

...stay on this time. This works with both the button on the receiver and the remote control. I would like to know what causes this problem and whether or not I should be concerned about damage being ...

...the left rear speaker functioned. This system has 3 front and 3 rear speakers, in addition to the subwoofer. I suspect that the issue lies inside of the receiver. I did open the receiver and clean ...