Inside that gold colored rectangular area is a magnet sandwich: top gold tint steel plate, gray strong magnet glued to underside of plate, air gap where coil travels back and forth to move head, steel plate for inner magnetic field return path, other half of air gap and coil, gray strong magnet glued to bottom plate, bottom steel plate. The really strong field is in that air gap on both sides of the center steel plate, right where the coil travels. Weak field outside the sandwich. If the spring got in there it would block movement of the arm assembly. If you can see it, it can be fished out with copper wire or something non-magnetic. It would be good to assure no spring trapped before trying the tape the shutter open and try writing 100 MB test I suggested earlier, do not want internal collisions!