Apple Service Diagnostic 3S123

Apple Service Diagnostic (ASD) is distributed to Apple Service Providers. The Apple Service Diagnostic application is designed to run both EFI and Mac OS X tests from an external USB hard drive. Apple Service Diagnostic (EFI) runs low-level tests of the hardware directly and does not require Mac OS X, while Apple Service Diagnostic (OS) uses Mac OS X to run tests.

Before using Apple Service Diagnostic, disconnect any Ethernet network, USB, and audio cables.

With the USB hard drive containing ASD 3S123 plugged into a USB port, restart the computer and hold down the option key as the computer boots up into the Startup Manager. To run ASD (EFI) select the "ASD EFI 3S123" drive icon and press return or select it with a mouse click. To run ASD (OS) select the "ASD OS 3S123" drive icon and press return or select it with a mouse click. ASD (EFI) will load in 20-30 seconds; ASD (OS) will load in 2-3 minutes. After running ASD (OS) or ASD (EFI), press the Restart button to restart the computer back into the normal startup volume, or hold down the option key to get back to the Startup Manager.

What's Changed in Apple Service Diagnostic version 3S123 ASD 3S123 replaces ASD 3S122.

Added support for iMac (20-inch Early 2008), and iMac (24-inch Early 2008).

ASD is no longer delivered as an image to be restored onto a DVD. ASD 3S117 and newer versions requires installation onto an external USB hard drive. For more information, please refer to the document "Installing ASD on a USB hard drive".

Apple Service Diagnostic version 3S123 Supports the following products:

*iMac (20-inch Early 2008);
* iMac (24-inch Early 2008);
* MacBook (13-inch Early 2008);
* MacBook Pro (15-inch Early 2008);
* MacBook Pro (17-inch Early 2008);
* MacBook Air;
* Mac Pro (Early 2008);
* MacBook (13-inch Late 2007).

NOTE: Installing Apple Service Diagnostic on a USB hard drive ASD version 3S117 and newer requires installation onto an external USB hard drive.

System Requirements:

* a Macintosh running OS X version 10.4 or later;
* an external USB 2.0 hard drive with at least 4GB or larger capacity;
* Disk Utility (located in /Applications/Utilities).