1) device has password set.
2) at home screen, hit the "K" key.
3) device is now locked.
4) screen and keypad lights will be out.
5) now, see if the top four buttons (call, menu, escape, hangup) are completely off, or are they very very dim.
i realised that the top four keys doesnt turn off completely. it stays lit but at a very very dim state. however, they will go off when i hit the keypad lock button.