Hello, new to the forums, and already asking for help! I have a Marantz SR4300 which I've owned for over a year now. It's been fine, however recently, seemingly randomly, there's an annoying crackling and popping (mostly crackling) type of background noise coming from the centre speaker only on my 5.1 speaker setup. This noise comes and goes as it pleases, but it seems to be getting more frequent. It happens even if the amp is the only thing plugged into the power, and regardless of output type selected (Dolby, Surround, Stereo, etc.) or source. I've tried different cables and wired up one of my other speakers, and neither of those changes made any difference. Any ideas on what might be causing this, or trouble shooting tips? Any help much appreciated. Thanks in advance.