I have a Sony STR-K840P 5.1 Surround Sound and lately I have been experiencing issues with the subwoofer\/bass speaker. The subwoofer does have power as it turns on and the LED glows green. However, when you turn on the subwoofer, after a second or two, there is click sound that is heard. When this click is heard the subwoofer works, bass outputs, but sometimes randomly it will click again and the bass stops. There are also other times when the subwoofer is turned on and it never clicks and it will not output any bass. I also tested that the RCA cable works, when the subwoofer is on and had made that click, when the other end of the wire is touched the subwoofer will output bass in a buzz, so I believe it is not an issue with the RCA cable. Any ideas what the issue maybe? or any suggestions on how to fix this? thanks for any help.