My sister got a quite new HP Slate 7 running Android 4.1.2, but the tablet won't charge. When I charge it while it's running, the charging is flickering between charging and not charging. If I charge while it's turned off, it displays the battery with a triangle and an "!" (exclamation mark).
It has been a permanent problem, but we used to be able to workaround it by tilting the device, sometimes that got it charging.