I've had this set for about 2 months now and have noticed that on digital, analogue and occassionally DVD signals, the picture momentarily increases brightness level slightly. This is with 100Hz on or off, and DNR on or off. Is there some way of accessing 'hidden' menus for this model? If so, is it a simple process of adjustment, or can anyone give me some guide lines? I'd greatly appreciate some advise from those more in the know than me!