My three-year-old Delta 1010 seems to have developed a problem. A few months ago I noticed that when I first power up I hear a hum coming from the card ... at least I'm pretty sure it's the card and not the breakout box. And the hum is LOUD ... I have to kill the volume on the amp until it passes. It used to take two minutes to fade away ... now it's taking 25 minutes. Has anyone encountered this problem before? And is it possible to just buy a replacement card and not an entire new system?