Hey all, I have a MBP late 2013 15 inch' and about a week ago suddenly my 'E' key became semi-responsive (never spilled liquid on keyboard). I turned it in to have it diagnosed by my local APR. Yesterday I got an e-mail from them in which they said that they will replace the topcase for free due to AppleCare. My question is: what exactly means a TopCase replacement? It is basically your keyboard and trackpad right? I just need to know this in case something happens to my machine after repairs! Also what can cause a key to become semi-responsive? Obviously in my case it is not caused by liquids as otherwise I wouldn't get the repair.