MacBookPro7,1 SATA controller issue

Hello,

I am trying to fix a friend's MacBookPro. It is a 13 inch MacBookPro 7,1 with Intel Core 2 Duo 2,4 GHz.

The issue was a gray screen on startup. I initially tried booting from the install DVD to no avail (the disk got stuck and I managed to get it ejected using a cardboard as described here). I tried the usual fixes associated to a gray screen, including Safe Boot and PRAM reset.

I am able to boot from the hard drive by mounting it from an external usb rack, which proves that the hard drive is fine (I tried replacing it anyway with another which had a working Lion install, to no avail). I managed to switch the internal SATA connector with another found in a working 13 inch MBP, which didn't solve the issue. For this reason I believe there is an issue with the SATA controller on the logical board.

I would like to know whether the whole logical board has to be replaced, if a replacement is easy to be found and if this is a difficult process. I'm also considering forgetting about fixing the internal hard drive port and replacing the superdrive with a hard drive, since the superdrive works. I guess this solution would cost less.

Many thanks for your help.

The two most occurring problems that reflect the error you're getting are: Bad hard drive and or defective SATA cable. You mentioned you replaced the SATA connector, and by that I'm assuming you replaced the entire SATA cable? If that's true, the only thing that remains is a logic board problem. And since you're able to boot the machine via USB with the same hard drive, that "might" indicate a bad controller.

However, I've never seen the controller go bad on that model MBP or for that matter, others. Not saying it couldn't happen, but it would be rare. I would try a new SATA cable before condemning the logic board controller. As you probably have figured out, the entire logic board would have to be replaced if the controller was bad. Not sure if removing the optical drive and replacing it with a data doubler kit to mount the hard drive is a good idea. Throwing money at a bad logic board is not practical - if in fact the controller is bad.

I would normally suggest running the Apple Hardware Test on that machine, but if the optical drive is not working right, I wouldn't attempt it.

Thank you for your thoughtful response. I also considered a hard drive failure or a broken SATA cable much more likely than a failure of the SATA connector. I did one more experiment: I removed the SATA cable and the hard drive and connected them to the logical board of the working macbook pro: it booted flawlessly. Therefore, I think that the logical board has to be replaced. I will give the computer back to my friend as I don't feel like doing that myself.

Thanks again.