William Kruidenier

Q: Monitor shows erratic colors when waking from sleep

Brand new Mac Mini, dual Dell monitors, OS 10.11.3. The monitor that is connected to the Mini with a Thunderbolt > HDMI cable, when it wakes from sleep, about half the time the monitor has changed to a purple cast covering the entire monitor. I can see the desktop but everything is colored purple. If I switch the monitor off for 10-15 seconds and turn it back on, the color scheme is usually back to normal. Doesn't happen on the other monitor that is connected with a HDMI > HDMI cable.

 

I only raise the issue here because my previous Mac Mini had video problems -- both monitors would randomly switch off to black screens requiring full Restart. I assumed a Mini hardware problem so bought a new Mini and now am having a monitor problem again on the new Mini. (I remember reading a couple years ago about monitor/video problems on Mac Minis.)

 

Question: before I conclude this is a monitor hardware problem, are there any known issues with a Thunderbolt > HDMI connection? I haven't bought and tried a new cable yet, but could that be a problem?

 

A graphics display card problem?

 

Thanks for any advice and suggestions.

Mac mini, OS X El Capitan (10.11.3), 16 gigs RAM

Posted on Mar 5, 2016 6:08 PM

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Q: Monitor shows erratic colors when waking from sleep

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  • by jason269,Helpful

    jason269 jason269 Mar 7, 2016 8:55 AM in response to William Kruidenier
    Community Specialists
    Mar 7, 2016 8:55 AM in response to William Kruidenier

    Hi, William.  

     

    Thank you for visiting Apple Support Communities.  

     

    I understand that you are experiencing color issues with a display connected via Thunderbolt to HDMI.  If you have tried an additional cable or adapter and the issue persists, try the troubleshooting steps in the article below.

     

    Thunderbolt ports and displays: Frequently asked questions (FAQ)

     

    Cheers

  • by William Kruidenier,

    William Kruidenier William Kruidenier Mar 7, 2016 9:04 AM in response to jason269
    Level 1 (49 points)
    Desktops
    Mar 7, 2016 9:04 AM in response to jason269

    Thanks Jason -- your reply made me remember that I wasn't entirely accurate about the connection to the monitor.

     

    The cable I am using is from my previous Mac Mini which did not have Thunderbolt but rather used the older Mini Display Port. The cable was a Mini Display Port > HDMI cable, not an actual Thunderbolt > HDMI cable as I previously indicated.

     

    Since the Thunderbolt ports on my new Mini will accept the Mini Display Port connection, I transferred the old cable to the new Mini set up. So, what I am now using is an older Mini Display Port > HDMI cable to make a current Thunderbolt > HDMI connection on the monitor where I am having color issues.

     

    Have no idea if that matters, but to make sure I have ordered a new Thunderbolt > HDMI cable just to eliminate the possibility of an older, errant cable being the problem.

     

    The only two "symptoms" of this problem are:

     

    1. it only occurs on waking from sleep mode -- going from a total black screen to a "live" screen

    2. the problem goes away when I turn off the monitor for 10-15 seconds, then turn it back on -- the color is then fine.

     

    The fact that my previous Mini had video problems -- both monitors randomly shutting off completely, at the same time, requiring a forced reboot of the Mini -- makes me suspicious about video in Mac Minis.

     

    I'll test the new cable for a few days when it arrives tomorrow and see if anything changes. Thanks for your input and the link to the Apple support file.

  • by lllaass,

    lllaass lllaass Mar 7, 2016 9:15 AM in response to William Kruidenier
    Level 10 (188,002 points)
    Desktops
    Mar 7, 2016 9:15 AM in response to William Kruidenier

    There is no Thunderbolt>HDMI adopter. It is just a mini displayport (mdp)>HDMI adopter.

    A subset of Thunderbolt is mdp with is used for video w/audio.

     

    However, there may be a problem with the existing mdp>HDMI adopter

  • by William Kruidenier,

    William Kruidenier William Kruidenier Mar 7, 2016 9:27 AM in response to lllaass
    Level 1 (49 points)
    Desktops
    Mar 7, 2016 9:27 AM in response to lllaass

    Thanks for the clarification on terms! Whatever it's called, I've order a new cable that connects to the Thunderbolt port on my Mini and the HDMI port on my monitor, so I am going to test the new cable to see if it changes anything.

     

    Thanks!