I have the 61" G series. I purchased it in July 05. When I first started using it, I thought the picture was kind of dark. I adjusted some of the parameters and got it to be a little brighter by using the high gamma setting. Using the brighness and increasing it seems to white wash the picture. Anyway, I have done nothing about it since. Yesterday, I was at a freinds house who also has the same TV. His picture is much brighter in general, and very slightly sharper. When he uses the high gamma setting, he gets a much brighter picture, and the difference between low gamma and high gamma has much more of a difference.
I do not think it is the lamp, as the level has stayed the same the whole time. Now that I know the difference, I was wondering what parameters I need to change to increase the gamma to brighten the entire picture. I have the service manual, but do not understand what any of the adjustable parameters are, and really do not want to make things worse. Is there a simple adustment in the service menu, or do I need a tech to come out. Other than that, the picture is excellent and so is the quality. I get the same levels on all inputs, including digital.