I have macbook pro early 2011 MC700 model. Few days back I was using it on battery and connected my samsung phone data cable to USB port and when I was about to connect other end of cable to my phone, macbook crashed. I took it to service centre and after few days technician told me macbook motherboard has short circuted and it need to be replaced. My macbook is just 3 month old and warranty has saved me from the cost of repair. I want to know what exactly is reason of short circuit. Is it fault in that model or this kind of short circuit of motherboard on connecting data cable is a common phenomenon. Now in future I will think twice before connecting my USB cable or pendrive to USB port of macbook. What can be exact reason of shortcircuit of motherboard. Thanks in advance.

Regards, Anuj


I youtubed/googled the issue and all I needed to do was remove the battery plug on the logicboard and I guess the system resets and it worked again. MacBook Pro alive.

How did I learn this? This happened to me at well. I had my MacBook Pro 17' connected to my Thunderbolt Display and when decided to charge my ipad using the USB and when I connected the iPad, everything shutdown. I couldn't even power it back on. Took it to apple store and they told me 500 bucks. WHAT$$$ They don't even diagnose the problem.

  • I'd be a little upset if taking it into the store, there was no troubleshooting and no attempt to reset the SMC/NVRAM and document what might be causing the issue.
    – bmike
    Sep 19 '13 at 20:09

Assuming everything the service center told you was accurate, and that it was really related to what you were doing with the USB cable, then the likely suspects are

  1. a faulty USB connector on the motherboard was faulty;
  2. a faulty USB cable; or
  3. a faulty USB connector in the phone.

Beyond this, we don't have enough information to know. Can you find out any more about the motherboard short-circuit, such as its location, from the service center?

I would certainly take the cable and the phone to the service center when I went to pick up my Macbook, and ask them to test both of them.

  • There could have been some damaged circuitry on the motherboard that simply short-circuited when the USB cable was connected.
    – Coyote
    Jan 9 '12 at 17:14
  • @jRobert Thanks for replying. 1). If USB connector on motherboard was faulty it should have happen earlier as I am using it for 2-3 months. 2). USB cable can be faulty as I have purchased it around 2 weeks back but I have used it for number of days before fault happens. 3). Phone connector cannot be blamed as phone was not connected at the time crash happen. The other end of cable was without any connection. Can you please elaborate more about location of motherboard shortcircuit location, what should I ask from technician about it. Also could it be related to static charge in winter season? Jan 9 '12 at 17:22
  • @Coyote you mean motherboard has damaged circuitry when I connected data cable, but when that damage to circuit happened. I was using macbook for around 1 hour before crash happened and it was working fine before the momnet I connected data cable. Jan 9 '12 at 17:25
  • Also I got this message 'One of your USB port is drawing much power and has been disabled' a day before or on the day of crash. I cant remember the exactly was it on the day of crash or before it. Could it be related with crash as initial warning signs. Jan 9 '12 at 17:27
  • A bit of solder that got loose inside either the motherboard's or cable's USB connector and shorted something could cause something like this. The message about drawing too much power supports that. The new motherboard would presumably fix a faulty motherboard USB connector, but you probably want to thoroughly test the USB cable before you use it again.
    – JRobert
    Jan 9 '12 at 17:48

The reason is that there are surface mount protection fuses on the board and releasing the battery resets them, just fixed it on my MacBook last week

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