It happened to me now. My K3 from september, just got a horizontal black line on the upper part of the screen. Many Restarts, resets, with/without lighted cover, fully charged etc. no change.
Sent an email to Kindle CS, so lets see what happens.
I'm too cheap to call CS from Denmark, but maybe I'll have to.
Fortunately it IS possible to read, but ... my baby needs help.
Is there a doctor in the house ?
