I went to the PhotoExpo Plus bash yesterday and spoke to the NEC folks about my problem with the NEC 3090 not holding the tilt angle because something was too loose. The rep pointed out a "button," really a plug, that covers a hole on theright side of the monitor's stand, as you face the display. Inside this hole is a screw, the purpose of which is to increase the friction that holds the monitor in a given position.
I started a new thread on this as I felt it would be more helpful to other NEC owners. The rep did not believe that the presence of the screw was indicated in the manual.