I've started to notice some light-dark horizontal streaking in the picture. Also some light green retrace lines are visible when the set is first turned on, as well as the screen collapses to a green dot when powered down. So it seems there may be some heater to cathode leakage after all. So far I haven't been able to capture the green retrace lines on camera, only the light-dark streaks. What do you guys think?
