Screen stays black on startup

Discussion in 'iMac' started by kwillems, Apr 1, 2018.

  1. kwillems macrumors newbie

    Joined:
    Oct 14, 2017
    #1
    I've got an iMac 27 2017 with an i7, the 580 graphics card and an SSD of 1 TB. I've extended the RAM to 40 GB.
    Everything worked fine, but the last couple of days the screen stays black on startup every once in a while. The fan is running and the screen get's black-grey (as it is 'on'), but than nothing happens.
    After putting the iMac off and on again everything works fine.
    I've already did reset NVRAM and SMC. Starting the machine while pushing D results in no errors.

    What can this be?
     
  2. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #2
    The RAM can be the problem, I think. If it is slightly out of spec, you can have weird things that can happen during boot, but generally, you have errors of some kind, and maybe the occasional kernel panic.
    What brand of RAM did you add to your iMac?
     
  3. kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #3
    I've used Crucial memory. I've noticed no problem with it so far
     
  4. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #4
    Do you usually shut your iMac off? or usually sleeping?
     
  5. kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #5
    I'm used to shut the iMac off; I guess that's a bad habit.
    --- Post Merged, Apr 1, 2018 ---
    Well, I'm going to reinstall the OS right now. Let's see what it will bring.
     
  6. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #6
    If it is still under the 12 months warranty do not muck about. Take it back even if it is a terrible job hulking it about.
     
  7. Papanate macrumors 6502

    Papanate

    Joined:
    Jul 21, 2011
    Location:
    North Carolina
    #7
    Before you bring it in - have you started it in 'Safe' mode?

    Also call Apple Support and see if they have a Fix or a bulletin
    about this behavior.

    Then if those don't work as @nambuccaheadsau just noted - if it's
    still under warranty (Apple Care or basic) bring it in immediately.
     
  8. kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #8
    I've reinstalled macOS, but the issue unfortunatly still occurs.
    I will contact Apple Support. My iMac is still under warranty. As far as I know their office will be closed tomorrow in my country, so i'll call them tuesday.
    Meanwhile, if anyone can explain this or has any suggestion, please let me know.
     
  9. jgelin macrumors 6502a

    jgelin

    Joined:
    Jul 30, 2015
    Location:
    St Petersburg, FL
    #9
    The RAM install guide from Apple says this is a possible behavior when first installing ram and it is initializing. Have you tried to reset the SMC to see if this fixes after the next boot up after?
     
  10. kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #10
    The RAM was installed in October when I bought the iMac. I had no problems until two days ago. I did already reset NVRAM en SMC with no result.
     
  11. Papanate macrumors 6502

    Papanate

    Joined:
    Jul 21, 2011
    Location:
    North Carolina
    #11
    He said he did the two common resets.

    --- Post Merged, Apr 1, 2018 ---

    Did you boot to safe mode?
     
  12. kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #12
    Sorry, forgot to mention. Yes, I did boot in safe mode. It gave no relevant information (as far as I can see) nor did it solve the problemen.
     
  13. kwillems, Apr 2, 2018
    Last edited: Apr 2, 2018

    kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #13
    I spoke with Apple Support; they appeared to be working today. They've asked me to bring the iMac in.

    But I did some further testing. That's in fact a matter of patience, because the issue occurs say once every ten times. The testing brings up two more questions:
    • Could this be caused by my HP Laserjet Pro CM1415fn printer?; It's connected with my iMac via USB
    • Also I noticed directly after booting the fan is speeding up to something like 1450 - 1480 rpm during 1.5 seconds. Is that normal behaviour?
    [EDIT]
    Forget my printer; after some tests the issue also occurs with the printer disconnected.
    [/EDIT]
     
  14. Papanate macrumors 6502

    Papanate

    Joined:
    Jul 21, 2011
    Location:
    North Carolina
    #14
    You could try one more thing. Take the Ram out - and then put a single stick in and boot.
    If it doesn't do the black screen after repeated boots - put the other stick(s) in one by one.

    Now that said - Since Apple says take it in - I would rather than waste my time solving their
    issue.
     
  15. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #15
    1. Take the self-installed RAM -OUT-. Restore it to factory configuration.
    2. Run like this for 2 days. Does anything change?
     
  16. kwillems thread starter macrumors newbie

    Joined:
    Oct 14, 2017
    #16
    I already removed the Crucial ram, but the issue still occurred (after 10 reboots).

    BTW: why two days?
     

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