This is a very valid question in terms of possible damage. I recommend getting a digital Gauss meter to measure the strength and size of the magnetic lines of flux leaving your 1200. Place your mpc just outside the field and you should be fine, well, unless your also concerned with possible stray eddy currents created outside the lines of flux onto any ferromagnetic surface of your mpc. Naw for real, you should be fine. Keep the Live, any cf cards or any old disks off the platters.