The Apple Hardware Exam (AHT) is actually a device for independent boot mode using the guidance of world wide web network that's depending on the Lion’s Web Recovery. This resource is very valuable if you have limitless net accessibility. But on the flip side, the software won’t do the job effectively for those who don't get on the internet all the time. The solution for this is copy the outdated AHT device on the OS X Lion boot generate, which ordinarily enables you boot it by keeping down the “D”. To carry out which you need to have a pre-Lion Mac with Mac OS X Installation and App install disks in addition to the DVD. Never overlook to ascertain irrespective of whether your Mac is able to make use of this.

If your Mac fulfill the prerequisites that's not delivered with Lion pre-installed, you simply do the following steps:
1. Insert the Mac OS X installation disk.
2. After it really is mounted, discover the volumes title and kind this command to duplicate yhe AHT diagnostic software to OS X Lion:
sudo cp -R /Volumes/DISKNAME/System/Library/CoreServices/.diagnostics /System/Library/CoreServices.
3. Authenticate the duplicate mainly because it promotions along with the technique folder.
4. Boot the Mac from AHT once again without having employing the online world recovery by keeping down “D”.
As details, it is possible to use AHT to be a diagnostic resources using the command line centered MemTest or hte GUI resource Rember to test the defective RAM modules.