When I switch the scanner on, it buzzes once and then just sits there.  The green plastic-like material on the armature seems to swell.  I have sanded it down a couple of times and the unit works for a while until it swells again.  Please help with a source for either a new motor or a new armature

Office Equipment & Supplies - Umax - PowerLook - PowerLook III Prepress Flatbed Scanner