Awesome fix, thanks! This exact issue was plaguing the up and down keys on my UX31 (this is after having to RMA the thing for power issues). Be forewarned, if you are attempting this on a machine that is in sleep or hibernation mode, it has the potential to shut it off, with no visible LED lights to indicate. You can reset by holding down the power button for ~10 seconds and it should boot back up, if not, check connections again.
The LED light on the charging cable is a decent indication if something's up or not.