Abstract: Apparatus for mitigating the adverse effects of magnetic interference on the operation of a CRT is provided. More specifically, magnetic sensors are placed in a gap formed between a front bezel and a rear enclosure comprising a magnetic shield enclosing all but the viewing surface of a CRT. The gap serves to concentrate the on-axis magnetic field and the resultant signal from the sensors is amplified to drive current through a compensation coil located inside the front bezel and in front of the viewing surface of the CRT. The current generates a compensation field that mitigates the incoming on-axis magnetic field. The ambient magnetic field is also sensed by a three axis magnetic sensing assemblage located outside the magnetic shield. The output of the sensing arrangement is operated on to produce a trigger to start a degauss cycle.