Hi. I just recently bought Axe-Fx 2 Mark 2 second hand. It was like new, still had the sticker on LCD. I've noticed after, that it's making high pitched squeel from the unit itself, not speakers. Even without all the leads plugged in. I've discovered that it is caused by cab/ tone matching block. Even if it is off, or not in the line. It just has to be there somewhere and axe starts making that squeely noise. It wasn't that bad few days ago, but today it has gotten pretty loud. I reloaded the firmware and did reset. Can anyone tell what that could be? And please tell me that if the unit is faulty I have Fractal warranty even if I bought it second hand. Thanks, Alan.