I have a Tek 2465 which I got refurbished by a seller on the bay. A few days ago the horizontal traces disappeared. When I press the beam finder they come up as blurry 3/8" dashes. Since they come up with the beam finder and the rest of the display seems to be functioning correctly I thought it might just be a calibration point that slipped. Is anyone familiar with this model? I'd hate to toss it when it doesn't seem too broken.