I was away for an overnight (by car) and the unit was in its cover and in the side pocket of my overnight bag. Do not recall hitting the bag or dropping it. Kept bag in trunk for lunch and the drive home and the temp got up to 80 that day.
How this happened is a real mystery since I do not abuse my digital equipment!
Leaning more toward "something happened" rather than "spontaneous".
I use my Nook HD+ cover which is not only rigid, but the unit fits snugly in the hard black plastic swivel section so the 840 has always been well protected. (See photos).
