My mother abandoned her 2011 MacBook Air after a spilled glass of water "killed" it. But three years later, to my surprise, it booted perfectly -- just three dead keys. Apple Store and others warned of a $700 repair fee (at least) to replace the top case -- when I suggested trying it myself the guy looked at me like I'd proposed setting up my own municipal sewer system. (And where would I get the part? he sneered.) But eBay got me a $100 top case in mint condition, iFixit provided the tools and knowledge, so I took the plunge.
Pretty much perfect. I set aside two quiet hours to do it, cleared a well-lit table and got to it. There was only one, non-mission-critical snag: the connector for the internal microphone broke off of the I/O board. So the machine has no internal mic, but I never use it, so that's fine. If I change my mind, I can get a $25 replacement I/O board and fix it. Now I've "got the bug" and want to open every machine.
I made a time-lapse video: http://www.jordanorlando.com/macbook_air
The step that I messed up -- the super-fragile I/O board connector (see above) -- was well-documented in the user notes on iFixit's repair guide (https://www.ifixit.com/Guide/MacBook+Air...). I was warned in very clear terms to be extra-careful when removing that part, including a detailed explanation of a recommended workaround. Anyway, be sure to go through all the commentary before starting your repair! Lots of great field-advice.
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