Mitsubishi big screen convergence prob.

Hi all: I have a six-year-old (warranties have long-since expired!) Mitsub. Diamond series 65" rear projection TV that has recently developed what I assume is a convergence problem. Pix is blurred, the three colors are visible (like looking at a 3D film without the special glasses) and the picture is warped and sort-of curved. Have tried the control to restore factory default convergence settings but without success. When the control is activated, the picture jerks slightly and the "factory default restored" legend appears, but the symptoms described above are not abated. Is there a usual cause for the symptoms described above? Is the problem fixable by a reasonably competent diy'er? If I order a service call, what should I expect to be charged for professional repair of this problem? Thanks for your replies! PE