Apple Hardware Test does not start

Posted on 2014-08-01
Last Modified: 2014-08-03
This is for in  iMac G5 running OS x 10.4. It is a customer iMac.

Apple Documentation says holding D key down during startup causes the the Apple Hardware Test (AHT) to run for intel baed MAcs (and I assume for Power PO based Macs too). Apple documentation ALSO says that for 10.4 the AHT is on the Install CD so I put the 10.4 install CD in the CD drive and restarted with the D key held down, got a single tone and THE AHT NEVER APPEARED. Instead a blue bar moved left to right and beneath it, it said Starting MAC OS SX and it never got beyond that screen.  I have tried holding the D key down for a long time after restart or a short time and I get the same result. I know the key board is being recognized because holding the eject key on the keyboard at boot causes the CD to be ejected. Also holding the option key down at boot let me to a screen with OS X HD showing in a rectangle which is correct if there is only one OS (OS X) on the HD

What am I doing wrong. How can I get AHT to run?

You may ask why do I want to run AHT. Because at first normal boot it made a noise that sounded like a fan; it was not a clicking noise like a bad HD. All later normal boots result in no noise and it goes to OS x startup screen and hangs there.

Customer reported noise at normal startup too.
Question by:mgross333
    LVL 27

    Accepted Solution

    On the older macs, you're supposed to hold the option key to boot from the Disc.

    Insert the Mac OS X Install Disc 1 that came with your iMac G5
    Restart your iMac G5 and hold down the Option key as it starts up.
    Click Apple Hardware Test when the list of available startup volumes appears.
    Click the right arrow.

    Author Comment


    I have held down the option key and restarted the iMac BUT not with the Mac OS X Install Disc 1 inserted. I will try that and let you know how it goes.


    Author Comment


    Upon 2nd thought, I am a little suspicious of this because I think that is effectively the same thing as holding down the C key in normal boot and booting from the install disk. Because the other volume should read OS X Install Disc 1, not AHT

    Please reply on that. And also have you actually done this on older MAC OR are you guessing. And I want to take this further. Have you actually done this with 10.4 MAC and 10.4 OS X install disk (preferably the one that came with the MAC but I suspect that is not necessary for AHT)..


    Author Closing Comment

    AHT ran per your instructions. However when I ran the Extended test in AHT, it said HD bad and then hung. As AHT runs from OS X Cd why would extended test hang? BTW Quick Test found no errors but results of Extended test takes precedence.

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