federico, here is my answer to a similar question "disassemble your Kindle. Follow this guide. You should check the solder connection on the micro USB port. It is very likely that they have either come totally of the board, or that they have micro cracks. It might be possible to reuse the old connector and resolder it, or you may have to find a new connector. The only place where I found them was on eBay, but very costly at $20 a piece. You could also check mouser.com or digikey.com for a micro USB that fits the dimensions of your Kindle. Hope this helps, good luck.