A fix for the Power/TV/Home buttons?

A year ago, the night I got my Wii U I accidentally dropped my gamepad about a foot from the ground. It continued to function perfectly.... ecept for the whole bottom row of buttons, including the battery light never working again. This includes the power button, home button, tv button. The mic and speakers continued to work.

Unfortunately some time ago without thinking I synced my friends gamepad to my Wii U, rendering my gamepad worthless, sense the only way it could come on was when I turned the console on. After buying 3 separate "refurbished" replacements with none of them functional in the slightest i wonder now if it's possible to fix my original one.

My question is: What could have happened to cause this inside and is it fixable?