I recently acquired an adapter that is a small, right-angle micro-usb B male/female .... ostensibly to connect my keyboard to my tablet and have the cable parallel to the exposed edge, and therefore not poking outwards and liable to get caught on something.  Also keeps the thin. fine cable in a straight line.

However, it doesn't work with the keyboard .... by that I mean using the adapter with the charger or an external drive it works fine, just not the keyboard.

Any ideas why?  Looks to be standard 5-wire beastie.