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  1. #1


    Member Since
    Aug 15, 2012
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    11
    Intel Pro Mac lost power unable to power on
    Hello,

    Yesterday I was working on Intel Mac Pro 3.2 quad core when I heard the "startup click" the machine makes when you turn it on and then my Mac powered down. After words I was unable to power it up again. It is dead, no sound, no fans spinning, just dead.

    I have this Mac on a UPS and in the couple of months or so I've had it, this is the first time I experienced any trouble. I've read this may be the power on switch in a few cases but mainly the PS. I had an older Mac Pro that in the past shut off once or twice on me but after that it worked fine.

    I saw the power switch panel. Can one jump the contacts on the power switch to see if the Mac powers on and if so switch combination?

    Thank you for your time in answering.

  2. #2

    harryb2448's Avatar
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    Imac 27" Retina 5K, 512GB flash memory, 3.3GHz, 16GB memory, macOS Sierra beta.
    Sounds like dead power supply. Only option if that is correct, replacement needed. Also some models have a fuse which can blow. Another suggestion, any chance you are using the Mac Pro with a circuit breaker? If so try without the breaker, and also change the power lead.

    And what model UPS? I use an iBox with my iMac but for a MAc Pro much stronger unit needed. Tried disconnecting the UPS?
    Hang on to those original install discs like grim death! Using OS X.7 or later make a bootable USB thumb drive before running Installer!

  3. #3


    Member Since
    Aug 15, 2012
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    11
    Thanks for the reply. I don't know if this unit has a breaker or not. The PS for these units is expensive. The UPS is fine. I checked the voltage at the power cord and is fine. Any issues with power and the UPS would sound off.

    This is the first PS I had go out in all the models of Macs I've owned. What I've read on line it looks as these units have some issues with their PS. Given their expense and proprietary nature, I'm a little hesitant. Any recommendations of sources for these PS's.

  4. #4

    pigoo3's Avatar
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    2011 13" MBP 2.3ghz, 8gig ram, OS 10.8.5
    Quote Originally Posted by bjr001 View Post
    Any recommendations of sources for these PS's.
    eBay.

    - Nick
    - Too many "beachballs", read this: Beachballs
    - Computer seems slower than it used to? Read this for some slow computer tips: Speedup
    - Almost full hard drive? Some solutions. Out of Space
    - Apple Battery Info. Battery

  5. #5


    Member Since
    Aug 15, 2012
    Posts
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    This family of Mac has a small button similar to the one located high on the motherboard for resetting the system. This button is located through the top memory riser opening. You will need a long screwdriver or such to reach into that cavity.

    Next to it are a series of LED lights that show a sequence when the button is pressed. This is what is used to diagnose issues of Macs not powering properly on yet still show some power reaching the mainbd/fans or power off after a short time. This shows if its the MB, PS or CPU is defective. I don't know the codes though you could always call an Apple store and ask.

    In my case it is simple as the LED's didn't come on as I had no power. I was able to obtain a used PS from a friend for this family of Macs and installed and all worked fine. It's been running fine for days now.

  6. #6

    pigoo3's Avatar
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    2011 13" MBP 2.3ghz, 8gig ram, OS 10.8.5
    Quote Originally Posted by bjr001 View Post
    In my case it is simple as the LED's didn't come on as I had no power. I was able to obtain a used PS from a friend for this family of Macs and installed and all worked fine. It's been running fine for days now.
    Very good…congrats on finding a solution! Sounds like the power supply was indeed the issue.

    Hope you had fun removing/installing the power supplies. I've done this…and although it is not super difficult…it does require some patience to do everything carefully and safely.

    - Nick
    - Too many "beachballs", read this: Beachballs
    - Computer seems slower than it used to? Read this for some slow computer tips: Speedup
    - Almost full hard drive? Some solutions. Out of Space
    - Apple Battery Info. Battery

  7. #7

    harryb2448's Avatar
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    Specs:
    Imac 27" Retina 5K, 512GB flash memory, 3.3GHz, 16GB memory, macOS Sierra beta.
    Finnicky is the word Nick .. finnicky.
    Hang on to those original install discs like grim death! Using OS X.7 or later make a bootable USB thumb drive before running Installer!

  8. #8

    pigoo3's Avatar
    Member Since
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    2011 13" MBP 2.3ghz, 8gig ram, OS 10.8.5
    Quote Originally Posted by harryb2448 View Post
    Finnicky is the word Nick .. finnicky.
    A good word for describing it Harry!

    - Nick
    - Too many "beachballs", read this: Beachballs
    - Computer seems slower than it used to? Read this for some slow computer tips: Speedup
    - Almost full hard drive? Some solutions. Out of Space
    - Apple Battery Info. Battery

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