My friend lost the box and charger with one of my FT2. Was running both FT2 on 1 charger for a while.I got my replacement power supply from Radio Shack, but it is not cheap. If I remember right, for the power supply, and the correct power tip (yep it is sold separately), it was about $45, but It does put out the proper Voltage and Amperage for the tablet.
Recently, I was window shopping in our local computer centres in Singapore & bought a replacement unit for just SGD20! That is about USD 17?