Focus is on the flyback inside. Usual warnings apply here - don't open a monitor and mess about unless you know exactly what you are doing.
Funny timing since I just dug mine out two days ago now that I got a set of ceramic screwdrivers to make adjustments. I don't recall it being as dim as it seems now but I did manage to get the colors tweaked well. Still need to clean/replace a couple of the adjustment pots on the front controls.