Hello, a week ago or so I noticed some strange noise coming from our Nanoscope IIIa "E"-Scanner. It sounds a little bit like a clatter of an old-fashioned self-timer. In addition to this, I wasn't able to adjust the A-B/A+B as well as the (A+C)-(B+D)/A+B+C+D. The A-B/A+B value was constantly increasing or must I say decreasing from -2