When I put my TP into my TouchStone, it starts to charge. After a while it stops charging. The TouchPad is not fully charged. I do notice that the TP/TS is quite warm. If I take the TP off the TS and put it back on, it won't recognize it. If I unplug the power adapter from the wall and plug it back it, it will start charging again only to stop after about another hour. Is the TS supposed to work this way or is my TouchStone busted?