I have an iMac (27-inch Mid 2011) and have a faulty CD drive (won't read or write DVD discs).
I have tried to start the hardware diagnostic check using D key on power up but the system pauses for a while then reboots normally. Am I doing something wrong.
I finally solved the problem. I will post what I did here in case anyone else has a similar problem.
Firstly, I don't have the installation CDs - the system is too new. Secondly, I had to reinstall the system at some point over the Internet (I screwed up the partitions).
So, If you hold down the D key nothing happens because there is no diagnostic software in the recovery partition. The solution is to hold down ALT+D, however, the initial screen response says "Starting Internet Recovery" which is misleading - I thought it meant reinstalling the system so I cancelled. I eventually left it running having read the following post http://macs.about.com/od/Troubleshooting/fl/Use-the-Apple-Hardware-Test-Over-the -Internet-to-Diagnose-Problems-With-Your-Mac.htm and the diagnostic software then started.
I finally solved the problem. I will post what I did here in case anyone else has a similar problem.
Firstly, I don't have the installation CDs - the system is too new. Secondly, I had to reinstall the system at some point over the Internet (I screwed up the partitions).
So, If you hold down the D key nothing happens because there is no diagnostic software in the recovery partition. The solution is to hold down ALT+D, however, the initial screen response says "Starting Internet Recovery" which is misleading - I thought it meant reinstalling the system so I cancelled. I eventually left it running having read the following post http://macs.about.com/od/Troubleshooting/fl/Use-the-Apple-Hardware-Test-Over-the -Internet-to-Diagnose-Problems-With-Your-Mac.htm and the diagnostic software then started.
Hold down the D key once you hear the startup tone. Continue holding it down until Hardware Test launches.
BTW, your SuperDrive may only need cleaning. Go to your local office supply store and get a CD/DVD cleaning kit.
Thanks for the suggestions, and yes, I will clean the drive. My main question though is how to access the Diagnostic check. No matter when, or for how long, I hold down the D key, it is always ignored. I also have a MacBook pro and access to the check works fine on there so I know it's not what I am doing. The only thing I can think of is that `I recently had a boot camp partition on the system which I have not delete; although I can't see how that would change things.
Do you have any more thoughts?
Your iMac should have shipped with the original Snow Leopard OS on two gray discs, Apple Hardware Test is on disc two of that original set. If you don't have your original discs you can try this tip;
How to run AHT w/o the system discs
1) SHUT DOWN the computer (Don't RESTART... shut it down)
2) Hold down the OPTION + D keys
3) Press the Power Button (make sure to hold down the OPTION + D keys first)
4) Continue to hold down the OPTION + D keys until the system enters AHT mode
5) Let the app verify the hardware setup before initiating the test.
6) There are two testing modes. To select the "Extended Test" activate the check box below the Test button.
7) Press Test button to begin test
iMac (27-inch Mid 2011) cannot start hardware diagnostic check
