Hello. Our camera originally had a bias level of about 105-110. It's been in storage for a number of years (last images taken in 2011), and recently was brought out to be used. The bias level is now at about 850. The bias images look fine; the level is just much higher than it has been. Nothing about the camera electronics has been changed. Could someone please explain to me what might cause this, and if it is anything to worry about? I've never seen this behaviour before. Thanks very much.