Got the same problem what I dit was disconect all cables except the battery cable then the tablet turned on vibrating, so by exclusion I find the board with the problem it was the board where the USB/Mini USB / Reset Button was, when I disconnected those it worked like a charm so to fix it I removed the board sprayed with WD40 pressed the reset button a few times(I believe the problem was the reset button got stuck or with a short circuit) put the board back on and its working like new, hope this help someone. :)