I'm sorry to hear this! Are you able to see this occurring all all sources and channels? If so the unit may require service. Here's the thread where you can get details on setting that up: http://forums.cnet.com/7723-13973_102-542437/service-issues-click-here-for-help/
Regards,
HD Tech
At a certain backlight level, the bottom 3rd of the screen gets much brighter than the rest of the screen. This issue seems to have started after the installation of the Evo kit and software update, although that may be coincidental. It also appears to be determined by what content is displayed on the screen, like it's auto-adjusting. I disabled all the dynamic / auto picture options, as well as the Eco settings but this has not helped. The photo below shows how it appears on a black screen (looks gray in real life, not blue as in the photo). If I lower the backlight setting, there will be a point where you can see it corrects itself. If you then increase the level by 1, you will see it flickering between its normal state, and this increased brightness. Increase the level by 1 more and the brightness issue becomes permanent. Anyone seen this before or have any ideas?
http://i60.tinypic.com/n6ev7t.jpg

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