I have an original 23w charger but when I plug in only shows as a 3w charger.  When I am using the tablet it is not charging and the battery is discharging.  I have tried various USB cables and they all show as 3w.  Does anyone know what the problem is.  I have read other threads and it seems to point to the particular USB cable that is needed which only comes from dell when tablet is sold.  However dell do not appear to sell the cable separately.

Any help please.