I just bought a used Summa S2 T140 and I am using Winplot to drive the cutter. I also have Onyx 12. My problem is that I get uneven cutting depth across the media. Sometimes the cuts are good on the left, and then cut all the way through on the right. I thought it might be the tape like others have mentioned, but the tape looks ok and I looked into some settings and noticed in the manual that the COIL settings should be set so that the head just touches the media, then backed off (3). The strange thing is that the head doesn't touch the media. It is a good 1/8" above the surface at its lowest setting. The way I was getting cutting results was to bring the blade out quite a ways, but I know it's not supposed to look like that. Does anyone have any idea if the tangential knife head is adjustable? Or if anyone else had this problem and found a solution? it may be a whole different problem, but the COIL is one thing I noticed right away.