I heard that if you so much as undo a screw on your machine except to swap out the RAM it voids your warranty.
Whoever told you that told you wrong. Nowhere does it state in the warranty terms that removing a screw voids the warranty. It does however state:
This warranty does not apply: ...
(b) to damage caused by accident, abuse, misuse, flood, fire, earthquake or other external causes
So if you manage to screw up your computer by removing a screw, you are liable for the damage.
Replacing the hard drive in a MBP yourself doesn't necessarily void the warranty either. In fact, I've asked this exact question to both an Apple Genius and a service representative on the phone. They both stated that it won't void the warranty, with the following exceptions:
1. The hard drive isn't covered under the Apple warranty if it fails; and
2. Any damage caused during the installation of the hard drive will void the warranty
On the other hand, we have this clause in the warranty terms:
This warranty does not apply: ...
(e) to a product or part that has been modified to alter functionality or
capability without the written permission of Apple
Which begs the question: does a replacement hard drive alter the functionality of a MBP? I would argue no, if only because Apple offer build-to-order hard drive upgrades for the same exact machine, which implies a larger hard drive doesn't mean a computer is being operated outside of its specification. We also see this here, which obviously implies certain upgrades are permissible (which presumably would include hard drives):
This warranty does not apply: ...
(d) to damage caused by service (including upgrades and expansions) performed by anyone who is not a representative of Apple or an Apple Authorized Service
Provider (“AASP”);
Historically, Apple have stated that upgrades such as overclocking do void the warranty. You can see this on older logic boards which have a piece of protective tape over dip switches which control the clock speed of the machine. Altering these settings obviously cause the computer to operate outside of its specifications.
So basically, the answer is no, replacing the hard drive on your own doesn't necessarily void the warranty. Furthermore,
it would be helpful if some people would not automatically come to a definitive conclusion before actually doing a little bit of homework.
Link to Apple's warranty terms.
