I have an eTrex Venture Cx that is just a few days old. This morning I turned it on, and drove a couple blocks and stopped at a light. I was looking straight at the GPSr when the screen went black. Actually it was mostly black, with random dots here and there that slowly faded out. I held the power button down and it came back up (welcome / splash screen, then had to reacquire, etc). I had just put new alkaline batteries in it a few minutes before. It's worked fine since. I do have custom maps on there I made myself (elevation contours), so I wondered if that had anything to do with it.