Some time ago, I dropped my Nexus while the Micro USB charging cord was still plugged in and, of course, it fell right on the plug. The Micro USB port on the Nexus was never the same (specifically the charging cord didn't fit in tightly any more) and the device got more and more finicky about the positioning of the cord until I couldn't get it to charge at all without holding the cord in a very specific position. I tried disassembling the Nexus far enough to try to bend the Micro USB connector on the Nexus back into shape, but no go. I decided it was time to replace the port.
All went pretty darned well. The "Nexus 7 2nd Generation Micro USB/Daughterboard Replacement" guide was spot on, and my Nexus is now happily charging again.
Have a magnifying glass handy. Particularly since a lot of this (like unlocking ZIF connectors) was new to me, being able to carefully inspect/twiddle was handy.
In Step 4 of the guide, I tore the protective foil cover a bit. Be careful.
In Step 10 of the guide, it says to carefully remove and store the factory seal on the screw. Good luck with that! No way it was coming off in one piece for me.