Danny has some excellent advice. That said, you should know that If Apple replaces any one part inside your MacBook, three times while it’s under warranty, and you have another failure of the same component, while it’s still under warranty, you’ll receive a Customer Replacement Unit: a brand new, currently shipping machine with specs as close to your machine as possible, at no charge, with a full, new 1 yr. warranty and the option to get the 3 year coverage.

Of course, having your indie shop (with a good rep, granted) failing to repair the unit 3 times, I would have gone to CambridgeSide by now. (hint, hint.)

The first thing that comes to mind, and perhaps not so surprisingly, is that the issues you’re encountering are not related to the Mac hardware or OS but with a particular (peculiar?) interaction of software applications that are installed and/or running at the time of the failure.

An approach that works for me is to perform a clean OS install (which, I understand you have done previously) and then methodically add your favorite and frequently used applications one-at-a-time. In other words, do not restore from a system backup or migrate *any* settings from some other Mac or from a Time Machine backup, etc. Treat it as though this is you very first computer you’ve ever configured…

At each step of adding a new component test for the issue – do the things that you think might have resulted in the failure in the past. When/if you are able to reproduce the issue, you may be surprised at your finding out what is (apparently) the root cause. And it may not even be an application, per se, but may be the data (e.g., a particular/peculiar Keynote presentation file) that is the culprit.

This approach almost always works for me. Good luck, David.

-Danny

Not gremlins in my case. The first case seemed to be a failed HD after about 3 months of taking delivery (it happens), the second was a dead logic board. I’ll let you know what the third is. Good luck with yours.

Yes, it could be you. And because Apple should back good science I’d like to see them give you a brand new machine to see if that one also succumbs to the infamous Weinberger Effect.

Seriously, Apple should replace this for you. With the newest version of Macbook. And an apology. Man…

Ok, in the event that there’s more troubleshooting – has the RAM been swapped or has it been consistent throughout? Same question about hard drive. If both of those have been swapped out it’s time for Apple to cough up a new machine. If not, the shop should (at their or Apple’s expense) swap both out. *Ususally* random crashes are 1) the motherboard, 2) the memory or 3) a connection from the motherboard to another system.

You might want to show this article to your shop, though it’s older:

http://maba.wordpress.com/2006/09/01/macbook-shutdown-solved-at-last-hopefully/

Interesting tidbit: “The phenomenon seems to be caused by the cable between the heat sensor and the CPU’s heat sink being too short.”