Can a Really Strong Magnet Permanently Damage the CRT?
Even a magnet that can suspend your weight may still not have much range as they usually have metal pole pieces that concentrate the flux and work well only with a matching flat steel plate. The only thing in the guts of a TV or monitor (that is accessible from outside the cabinet) that can be damaged permanently is the shadow or slot mask of the CRT. If the magnet is strong enough to distort it, the CRT will be ruined. Even manual degaussing with a similarly powerful degaussing coil will then not totally clear up color purity problems. The shadow or slot mask is a very thin perforated steel or InVar sheet about 1/2 inch behind the glass of the CRT screen – which is itself about 1 inch thick or more. So, even up against the screen, your magnet is still at least 1-1/2 inches from the shadow mask. It would take a mighty powerful magnet to distort it. For Trinitron (or clone) CRTs with aperture grilles – tensioned fine wires in place of a shadow or slot mask, the force required would be e
