I have a 73 inch tv, the picture is very dark especially if it is showing nighttime, I have already cleaned the bulb in the back and dusted it, and it is still very dark, what can I do?
Yeah, sounds like you need to replace the bulb. The bulbs on these projection TVs would "wear out" and grow dimmer with use. Usually they're rated for a few thousand hours before it'll dim to half the brightness when new. If you watch TV 4 hours a day, 5 days a week, that's about 1000 hours a year.