low on startup, black x over battery
My battery can't charged it always shows black x, wifi sometimes can turn off by itself and won't turn on now its getting worst it said no hardware installed. And it always low on startup I must wait until at least 3 days to open it normally, but once I shut down it'll back like that. Then I try to re-installed my mac, but on wifi display it said:no hardware installed. I searched for solution but got confused. Please help me!
Sounds to me like your battery could be cracked, and whatever cracked it (stacking, squeezing) may also have damaged or loosened your airport card.
I had a laptop in an overhead bin on an airplane upon which a fool placed his carryon on-top of mine. It cracked the battery, but of course I didn't realize it at the time. My MBA exhibited strange charging booting behaviors, the black X would appear/disappea
Finally I opened the box and looked around - couldn't see anything wrong… reassembled, problem persisted… figuring it must have something to do with the battery I reopened the box and when I lifted the battery a crack could be seen running across it (crack was invisible when resting flat). Apparently moving (torquing) the case would cause/solve the short from the battery making all my problems intermittent.
If you have had something stacked on your laptop, or, if you dropped your laptop you may have the same problem.
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