I have a 1993 46" Rear projection Phillips/Magnavox. In the the past weeks 1/4 of the screen on the right side turned a little darker(greenish) than the rest of the screen.I cleaned the lenses an the mirror, with no luck. Ive heard about convergence, but since my TV is a 93 I don't have the option on the remote/menu. Under my mainboard I have something called hv/dist block. Should I try to play with that when the TV is open/closed? I also have many nob's on my mainboard (green ll, blue ll ...).