Macbook completely dead?

[disconap]

This is driving me insane; the problem itself is fixed, but I do not understand AT ALL what the problem was. So here are the symptoms:

My client came to me with a Macbook that wouldn't boot. Most of the time it hung on the gray screen, occasionally it would get to the "blinking folder" stage. It wouldn't boot into target disc (firewire) mode, wouldn't boot into Single User or Verbose modes, wouldn't boot from a dvd or cd-rom, it was just dead. Tried every trick in the book (playing around with the RAM configuration, resetting PMU [or CMS or whatever it is in the Intel models], trying to boot into the open firmware, etc) and nothing worked. At all. This machine was dead. The only thing it would boot was the hardware test disc, and it passed every test, then failed to boot into the OSX install DVD that Hardware Test is on.

So we tried replacing the hard drive with an old Tiger hard drive. And boom, everything worked. Solution: bad hard drive.

Here's what is driving me insane--some of those solutions (booting from various DVDs, booting into Open Firmware, Target Disc mode, etc.) should, in theory, work regardless of whether or not the hard drive is dead. Anyone have any idea why this would happen?

 

[NewMacbookPlz]

More of a circuitry short on the old hard drive maybe? The platters/data may have been fine, but if the electrical systems of it are fried could it cause the issues?

 

[upinflames900]

The boot information is stored on the hard disk so if that information gets corrupted that will cause your problem. So it is not even necessarily a bad hard drive even...although more of a probability than normal. The boot information tells the computer how to react to target drive, normal boot, CD boot, etc. I have had this problem before so I know. And the worst part is you sometimes get lucky once in a while and it would boot.

 

[disconap]

But what I don't get is you can insert a blank drive and still boot from the DVD, right? Or is it a drive firmware issue? Like that info is in the firmware or the core format of the drive (pre-OS install) and THAT is what's corrupt?

 

[upinflames900]

But what I don't get is you can insert a blank drive and still boot from the DVD, right? Or is it a drive firmware issue? Like that info is in the firmware or the core format of the drive (pre-OS install) and THAT is what's corrupt?

I am pretty sure the boot info for booting from a DVD is located on the hard drive in a special location and not in the firmware or any other part of the computer. So in essence you should not be able to boot via a DVD unless you have a hard drive in the machine.