PSU Dead?

Discussion in 'Mac Basics and Help' started by Elven, Sep 30, 2013.

  1. Elven, Sep 30, 2013
    Last edited: Sep 30, 2013

    Elven macrumors 6502a

    Elven

    Joined:
    May 13, 2008
    Location:
    UK
    #1
    Hi all

    Before I have my iMac booked in to be repaired I would like to ask the community if they believe as I do that my power supply died.

    I have my i7 iMac which was working just fine, went for some food came back to it turned off. Their was no burning smell, it was as if the power was turned totally off.

    I then ran checks

    1. Spare Lead Used

    2. Disconnected for hours

    3. Removed all usb devices


    All recieved nothing, upon pushing the power button, nothing is heard at all it is as if the iMac has zero power.

    I am about to call out a repair guy to fix the power supply, and just wondering if their is anything else I should do?
     
  2. Elven thread starter macrumors 6502a

    Elven

    Joined:
    May 13, 2008
    Location:
    UK
    #2
    Quick bump but any tips to check before I pay for the repair would he awesome.
     
  3. Mr Rabbit macrumors 6502a

    Mr Rabbit

    Joined:
    May 13, 2013
    Location:
    'merica
    #3
    I'm assuming you've tried a different electrical outlet, have tested the outlets with other electronics and have tried a different three prong power cord.

    All of the 27" iMacs have diagnostic LEDs built in, however their location depends on their specific generation. Since it's out of warranty I'm going to assume it's at least a mid-2011 or older.

    On the mid-2011 27" iMac the diagnostic LEDs are just to the right of the middle of the logic board, on the front (display) side.

    On the mid-2010 and late-2009 27" iMacs the diagnostic LEDs are located on the bottom left of the logic board, just to the left of the RAM slots, and are visible through the lower grill of the aluminum housing.

    All of the LEDs function in the same way though...
    • LED 1 indicates trickle power from the power supply has been detected. This LED should be lit whenever the Mac is connected to power.
    • LED 2 indicates that the computer is powered on. You should also see fans spinning and hear hard drive / optical drive noise. This will be on if the power supply is working properly.
    • LED 3 indicates that the logic board and video card are communicating properly.
    • LED 4 indicates that the logic board & video card are communicating properly with the LCD panel.

    When dealing with power issues the diagnostic LEDs can be very helpful in verifying the states of the power supply.

    Hope that helps!
     
  4. Elven thread starter macrumors 6502a

    Elven

    Joined:
    May 13, 2008
    Location:
    UK
    #4

    To see the led I would have to first open the iMac? It is indeed a 2011 model I bought last year before the slim iMacs came out.
     
  5. Mr Rabbit macrumors 6502a

    Mr Rabbit

    Joined:
    May 13, 2013
    Location:
    'merica
    #5
    If it has two Thunderbolt ports then it is indeed a mid-2011 model, you would need to open it up to see the LEDs.
     
  6. Elven thread starter macrumors 6502a

    Elven

    Joined:
    May 13, 2008
    Location:
    UK
    #6
    Lovely out of warranty, I've not the tools or skills to open it, I live in middle of nowhere without a lift, and my main work computer is dead and thank you Apple for making it inacessable for a simple psu repair.

    Not a happy bunny as it's a £250 call out to my place.
     
  7. Mr Rabbit macrumors 6502a

    Mr Rabbit

    Joined:
    May 13, 2013
    Location:
    'merica
    #7
    Any consideration for buying the tools and doing it yourself? These are actually the easiest Intel iMacs to work on in my opinion (the 27" non slim). My only concern is the power supplies pack a punch if they shock you, I recommend extreme caution when working near one.

    Power supply available at iFixit

    Suction cups at iFixit (honestly one decent suction could would probably work, even just using a sharp edge to pull the glass away just a bit works fine too)

    Pro Tech toolkit at iFixit - This toolkit is great. I've used one for literally hundreds (thousands?) of repairs.

    Really those toolkits come in handy with any electronics repair. The power supply replacement isn't terribly difficult aside from the need for extreme caution.
     

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