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Verkaufsstart Juni 2012, Model A1278. Intel Prozessor mit Turbo Boost

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MacBook turns off when charger is disconnected


Around two days ago I was about to move my workhorse to the kitchen, to do some culinary research (read: how to boil potatoes) when my MacBook just turned off when I disconnected the charger. I've had this problem before, which went away after a short while by itself. I just pinned it down to magnets or magic. After a while of being mildly annoyed by it shutting down, I began testing the battery in TechTool, which gave me virtually no information save for the fact that the battery is just maintaining its charge, but not actually getting any.

The battery indicator shows a 100% charge, as does Coconut Battery, which should mean that it's not the SMC. I did an SMC and PRAM reset, though it's unclear if it did anything at all. I'll try an SMC bypass and see if that does anything at all and update on this.

Logic tells me that it's the I/O board which is fooling around, but given my current financial situation, I don't want it to be. So, bottom line, is there any way to be completely sure that it's due to the I/O board, and/or any good way to fix it? Any help will be very appreciated and will hopefully help others in the future too.

Update (11/23/2016)

For the sake of clarity, I'll enclose two Coconut Battery screenshots for future reference.

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Beantwortet! Antwort anzeigen Ich habe das gleiche Problem

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Tried nothing worked for me


I had this problem too. Tried everything this forum tells you.Finally what worked for me is that I took it to Apple service centre and all he did was to disconnect the battery from inside and reconnect it. Probably there was a loose connection of the Battery inside with the system. Thankfully it worked. I made an effort to come back here and mention this, as this was an easy solution and one may overlook this point.


Thank you for your response.

Did you mean all the battery system or just the connector? Because I tried to pull the connector and then push it strongly to avoid a loose connection, but it didn’t work. I didn’t try to remove the battery though.. If you tell me that removing all the battery system worked for you, I may give it a try..


Hi, I have a similar issue. My Macbook air works when unplugged but suddenly crashes when it reaches about 80 percent. I never know when the crash will happen but I keep losing important stuff so this is annoying!


Exactly the same behavior, in my case caused by corrosion on the I/O Board. Cleaning with a toothbrush and Iso alcohol, the problem was solved.


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Gewählte Lösung

I bet you leave your system plugged in most of the time.

What is happening here is SMC thinks the power level is below the set threshold so it needs to power down the system into deep sleep mode.

So how to fix? It's quite simple you need to do a SMC reset and cycle the battery a few times by fully discharging it and recharging it. That way the setpoint is memorized correctly.

Here's the Apple TN you'll need to reference: Reset the System Management Controller (SMC) on your Mac

The other method is disconnecting the Battery and pressing the Power button for 15 sec’s to fully discharge the logic board, then plug in the battery and MagSafe. The system should restart on its own.

And lastly, check your battery! Install this gem of an app! CoconutBattery take a snapshot of the apps main window and post it here for us to see Bilder zu einer vorhandenen Frage hinzufügen

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I bet you didn't read my post in which I said I reset the SMC. As far as my battery goes, I try my best to not have it plugged in most of the time and give it a chance to fully empty out before plopping the charger back in. However, I did just open the MacBook up and tinkered with a few wires, which seemingly did nothing. Then I did an SMC bypass (unplugging the laptop, holding the power button for 10 secs, plugging the computer back in while holding the power button for an additional 10 secs and then releasing and pressing it again to get it to boot) which got it up and running without a charger plugged. From there, I just did yet another SMC reset, booted in safe mode, checked TechTool and everything looked positive - this time with a 0% charge (as opposed to the 100% charge reported earlier). No clue what caused the Mac to report a faulty battery/I/O board, but we're back to normal. Again we can nail this down to magnets and magic.


Did you pull the battery connection? Often I find I end up needing to do it that way to be effective. Pull the battery internally, press and hold the power button a good 2 minutes then plug the battery back in and restart.

No magic here and it's not magnets either :-) I confess I did skim your Q. It's a problem I've seen a few times so I had a strong idea what was up here.


You may want to clean the MagSafe connector pins and pads. The middle pin is how the charger and the system communicate. If the cord pins or the DC inboard contact pads are dirty or corroded you can have some charging issues. But given your coconut battery info I don't see this as your issue.


The Chicken and the Egg problem ;-}

The premise here is once SMC is reset it does not have either a high or low threshold set. So once done you need to completely drain the battery until SMC see's the low threshold voltage wise has been hit it will then shutdown. Now recharging the battery and then repeating will set the high point. That should do it!

Now the but! The voltage comparator logic on the logic board needs to be working properly. If SMC is prematurely shutting down after a reset there is a problem on the logic board. Often corrosion has built up on the one or more of the components that set the value or the chip its self is defective.


How did you solve the problem? I appreciate your help!


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Hi, I might have a similar problem. My MacBook Pro shuts down suddenly sometimes when I move it and the charger gets disconnected. It doesn't always happen, so I'm sure that it's not a battery problem. It turned out it's a problem with my charger. Perhaps it sends some surges of electricity or is otherwise unsafe that the MacBook decides to shut down. Anyway, the problem seemed to have disappeared when I got a new charger.

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I agree, in most cases this is a charger issue, specifically the L tip magsafe cable. Since my original magsafe disintegrated, I have used numerous compatible adapters and they all develop this issue over time. When it starts to happen, I just get a new charger.


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Henning Klepp Christensen wird auf ewig dankbar sein.

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