My MacBook had been acting fine. I applied the latest update to Mountain Lion and closed the lid. When I opened the lid, it wouldn't wake from sleep (dark screen with whirring fan for ~5mins). I held the power button and it rebooted to a dark grey screen. I reset the pram using Cmd+Option+P and it booted to the grey screen with flashing question mark. So I rebooted with the install disk for lion (I didn't make one for 10.8). Disk Utility doesn't see my root partition, it does however see the Mac OSX Base System 1.4 GB partition (I'm not sure if this is actually on my HDD or if it is a virtual file system created by the install disk). In any case, I swapped out to my OEM hard disk and rebooted. Disk utility still only sees the Mac OSX Base System. diskutil list reports the same. I can't reboot to recovery via Cmd+R or via holding the Option key. I also don't hear the hard drive spin up. At this point I'm thinking that I have a bad motherboard.

Is there any way to confirm that the motherboard is indeed bad?

  • Your motherboard (logic board in Apple parlance) isn’t bad, your hard disk probably is.
    – duci9y
    Sep 12 '12 at 9:11
  • I dunno, @duci9y. Swapping out the drive and getting the same issue? I vote for logic board too.
    – user479
    Sep 12 '12 at 19:27

It was the logic board. I'm using the hard drive now as an external drive with out problem.


My iMac 27" 1TB HDD died, and we phoned around for a replacement HDD. We were offered on many occasions to take the machine in to them to repair ... for $600 !! Well we bought a new 1TB HDD as per recomendation, as utilized the power of Google and YouTube.

We taught ourselves how to replace the HDD, and did. However, with an unfomatted HDD the iMac could not "see" the new HDD.

What we found was to load a full OS X onto an external HDD by using our MacBook. Once that wasdone, we then plugged into the iMac and found that the iMac could now "see" the new internal HDD. We formatted the internal HDD using the Guid Partition Table.

Use the following AWESOME link to continue your journey to replace the OS on your Mac.


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