chriscarvalho

Q: iMac 20" won't boot past black screen

Hi guys,

 

Thanks for taking the time to read about my problem.

 

My iMac won't boot past a black screen. Before it would randomly restart and I would perform an SMC reset which would normally sort it.

 

It's old, probably 2008 model but I can't afford to replace it quite yet.

 

I've tried different power cables to no avail. PRAM doesn't work. I don't think it even gets to power the keyboard before trying to boot again.

 

I can hear the fans spin for a few seconds before I hear that click before it reattempts. It gets stuck in a loop before I have to remove the power cord.

 

It was working mostly fine until I created a new user login the other day.

 

Any thoughts?

 

Much appreciated.

 

Chris

iPad 2, iOS 5.0.1

Posted on Jun 1, 2016 3:37 AM

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Q: iMac 20" won't boot past black screen

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  • Helpful answers

  • by D.Cohen,

    D.Cohen D.Cohen Jun 1, 2016 3:45 AM in response to chriscarvalho
    Level 6 (8,424 points)
    Desktops
    Jun 1, 2016 3:45 AM in response to chriscarvalho

    Take a look at the steps suggested by Apple in this article:

    If your Mac won't turn on - Apple Support


    Try Safe Boot:


    - Shut down your Mac

    - Wait until your computer turns off and after that press the Power button

    - Right after you hear the startup tone, press and hold the Shift key

    - Release the Shift key when you see a grey Apple sign and the progress bar below this sign

    - After your Mac boots up, restart it as you usually do.


    If this doesn't help, follow the instructions below:


    - Shut down your Mac

    - Wait until your computer turns off and after that press the Power button

    - Right after you hear the startup tone, press and hold the Shift key

    - Release the Shift key when you see a grey Apple sign and the progress bar below this sign

    - Once you see Desktop, start a Disk Utility scan to detect and repair file system errors (don't forget to choose your main hard drive)

    - Click on Verify Disk and then, if asked to fix problems, on Repair Disk

    - After this, click on Verify Disk Permissions and then on Repair Disk Permissions

    - After the process is finished, shut down your Mac and turn it back on after about 30 seconds


    Apart from that, take a look at this Apple article and follow the instructions on Resetting NVRAM shown there: How to Reset NVRAM on your Mac - Apple Support


    Try resetting the System Management Controller: https://support.apple.com/en-us/HT201295


    Hope this helps!

  • by chriscarvalho,

    chriscarvalho chriscarvalho Jun 1, 2016 4:03 AM in response to D.Cohen
    Level 1 (4 points)
    Desktops
    Jun 1, 2016 4:03 AM in response to D.Cohen

    Thanks for this.

     

    I tried powering on by holding the power button for 10 seconds and it now seems that the Mac is staying on (I can hear the fans and it's not restarting itself) but the screen is blank.

     

    Any further thoughts?

     

    Your help is massively appreciated.

  • by chriscarvalho,

    chriscarvalho chriscarvalho Jun 1, 2016 4:04 AM in response to chriscarvalho
    Level 1 (4 points)
    Desktops
    Jun 1, 2016 4:04 AM in response to chriscarvalho

    Please note also that there is no chime.

     

    C