If you go further up the thread you'll find that others reported overheating issues with the 696 (and 496 too). I also saw people reporting overheating issues when leaving it in the sun on other forums. Seems the display brightness goes south when it overheats. Once the heat is gone, everything seems to go back to normal. I haven't had this issue with my 496 unit, but I usually take it out of the sun when I shut down at the airport for a while.