My MacBook Air completely quit. No power at all. No video. No Fan. Nothing. It seemed clear that it must be the battery or the MagSafe card.
The repair never really happened because it was discovered that the actual problem was on the logic board. I am delighted that iFixit has a return policy that allows me to return the parts for a refund (there is an understandable restocking fee). I am VERY happy with this!!
Working with iFixit has been nothing but pleasant. Great detail on how to debug and fix. A great supply of parts, even for older models. And as I say above, a generous return policy for us idiots who order the wrong parts.