2012 Mac mini - Won't wake monitor via DisplayPort

Discussion in 'Mac mini' started by A4orce84, Jan 8, 2019.

  1. A4orce84 macrumors 6502

    Apr 17, 2012

    I have a 2012 mac mini 2.5 GHz Intel Core i5 running running MacOS Mojave with 2 external monitors hooked up via HDMI and DisplayPort.

    The Issue:
    The monitor connection works correctly (I'm typing this on it now), until I attempt to wake the monitor from sleep. The Mac Mini itself clearly wakes when I click the mouse (the white light stops blinking and stays solid) and the monitor via HDMI wakes up properly. The issue is intermittently (non-consistent) the DisplayPort Monitor does not receive a signal, and does NOT wake up. I have to perform a restart of the machine to be able to use the DisplayPort monitor again.

    Can anyone offer any advice about this? It's very annoying not being able to quickly wake up the display when I need to use the Mac and have to perform a restart.

    Thanks in advance for everyone's time and help, it is greatly appreciated!
  2. oikos macrumors newbie

    Jun 12, 2013
    --- Post Merged, Jan 8, 2019 ---
    I have had a similar problem with a 24" external NEC monitor (PA241) hooked up to either my 2012 Mini (maxed out Server model, but not used in Server mode; running OS 10.11-El Capitan), or to a 2017 MacBookPro 13" i7, Sierra, when I put a CalDigit TB3 Hub in between the monitor and the computers. (The problem started when I got the hub to connect the NEC monitor to the MacBookPro, but it has carried over to the Mini when I'm still using the hub for its extra ports. (My old Apple 20" CinemaDisplay that is simultaneously connected through DVI to HDMI converters and a Sonnet Echo 15+ TB2 dock does NOT lose connection.)

    In my case, this appears to be a problem of DisplayPort protocols not working properly through a TB3 hub, which I've read is a known problem. My monitor actually loses the connection in the middle of an active process (not sleeping) - the screen just says it has lost connection and goes dark. Rather than rebooting, I usually have to fiddle with the monitor's input and power switches a few times to get it to come back on. Sometimes takes 1 minute, sometimes 5 or 10. I'm hoping to overcome by getting a new 2018 MacMini or iMac, which I'd like to go to 4K or 5K monitors for photography anyway. We'll see...

    Am interested to see if others are having similar issues, and any other solutions that have been found. GOOD LUCK!
  3. stratokaster, Jan 9, 2019
    Last edited: Jan 9, 2019

    stratokaster macrumors member

    Jul 30, 2011
    Dublin, IE
    It's interesting because I have the same problem with Mac mini 2018 and my 4K monitor (LG 24UD58-B). It works perfectly if I hot-plug it into the mini (using a USB-C/DP cable), but if I reboot the mini or wake it from sleep, there's a 50/50 chance of it waking up the monitor. The monitor works perfectly via HDMI. I tried two different USB-C/DP cables (same result), also tried this monitor with a PC (using the DP port) and it wakes up perfectly with a PC every time. I don't use any hubs or port extenders with the mini.
  4. Gudi macrumors 68030


    May 3, 2013
    Berlin, Berlin
    Samsung SyncMaster 2493HM connected via HDMI to a Mac mini 2012 and via DVI to a PC. The Mac always connects to the monitor on the first try. The PC needs half an hour of warmup and multiple reboots before it gets a signal through.

    It’s most likely a faulty transistor within the monitor itself. Look at Youtube for DIY repairs of your specific type of monitor.
  5. purplealert macrumors newbie

    Dec 17, 2018
    Devon, UK
    Yes, I can confirm this is one of the issues I have with my Mac mini(i7/32/512). I also have an LG 24UD58, a very good monitor. If I drive it via the USB-C->DP cable the screen will intermittently not wake from sleep(tried multiple cables which work properly with other machines). It will usually wake if I put the machine back to sleep and click the mouse or pull the cable and replug. Not a good experience for a new computer.

    I'm in the fortunate position of also having an eGPU(RX560) which I sometimes use with this machine. I drive the LG monitor from and when using the eGPU I never have this issue.

    I also have an Apple Cinema HD display with a usb-c->DVI-D adapter, this display always wakes from sleep correctly.

    I'm almost certain that this is one of several firmware issues with these new Mac minis. I also have significant problems with USB hubs and keyboards/mice, particularly after reboots. USB devices which work perfectly with other Macs.

    I need to make some time to speak to Apple Support regarding these problems as I think they need to issue a firmware update for these machines. I'm hoping they're already aware of most of the issues but more reports help.
  6. enri1357 macrumors member

    Jul 31, 2016
    I am almost certain that they will tell you: it is interference or your adapter (they seems treat cables the same as adapter)

    I am on the same boat :(

    They don't seems care about our problems

    edit: yet it is good to give them one more case for these display issues
  7. Fishrrman macrumors P6


    Feb 20, 2009

    You've probably already tried this, but...
    What happens if you power OFF the display (the one that's connected via displayport), and the power it back ON again?
  8. Chiromac81 macrumors regular

    Nov 18, 2018
    Ontario Canada
    Speaking of this question: I am getting a Mac mink next week and want to set unit up with DisplayPort with my current 2012 iMac screen until I find a suitable monitor. What do I need to purchase to make this work or will the cables already be included for this setup?
  9. A4orce84 thread starter macrumors 6502

    Apr 17, 2012
    Unfortunately, just powering off / on the monitor did not solve the issue. Is there something else I should try?
  10. tombaja macrumors newbie

    Dec 4, 2018
    La Paz, Mexico
    Do you have your monitor configured for auto-detecting the input ports? If so, try to deactivate this feature and set the port manually to Display port in the monitor configuration.
  11. Partron22 macrumors 68020


    Apr 13, 2011
    Swapping the two monitor's connections worked for me.
    It seems some displays wake slower than the Mini is willing to put up with.
  12. tombaja macrumors newbie

    Dec 4, 2018
    La Paz, Mexico
    I observed exactly the same, the Display port on my Viewsonic 2771 takes much more time to connect than the HDMI port.
  13. A4orce84 thread starter macrumors 6502

    Apr 17, 2012
  14. A4orce84 thread starter macrumors 6502

    Apr 17, 2012
    Hey Guys,

    First off, thank you all for all of your suggestions and help so far. It is greatly appreciated!

    So I swapped cable connections, and only the monitor connected to HDMI worked. The DP connected monitor still remained with a 'no signal' error on a black screen.

    So to be clear, I may have described the problem a bit incorrectly. So let me do a quick clarification:

    The Issue:
    The monitor connection works correctly (I'm typing this on it now), until I attempt to wake the monitor from sleep. The Mac Mini itself clearly wakes up when I click the mouse (the white light stops blinking and stays solid) and the monitor via HDMI wakes up properly. The issue is intermittently (non-consistent) the DisplayPort Monitor does not receive a signal, but it WILL wake-up. The message that is on the Dell connected via DisplayPort is just a black screen that says, "No Signal Detected."

    I have to perform a restart of the machine to be able to use the DisplayPort monitor again.

    Anyone have any other things to try to get the DP (DisplayPort) monitor working and receiving a signal correctly upon waking up?

  15. A4orce84 thread starter macrumors 6502

    Apr 17, 2012
    Bumping this back to the top. Anyone that can offer any assistance would be greatly appreciated!
  16. masterbaron macrumors 6502


    Nov 22, 2012
    3rd Planet from the Sun
    I cannot help you or myself but I can tell you it's a handshake issue perhaps coupled with a timing or sequence issue. We will not resolve it without a piece of gear that continuously sends the needed handshake - be it a chip-embedded cable, signal box/switcher or software/firmware update from Apple or your specific vendor.

    Not sure why this is a low-level issue for Apple other than telling you to upgrade your monitor or change connection methods.

    Sad as more and more fixable issues remain open with Apple support.
  17. DeltaMac macrumors G3


    Jul 30, 2003
    I think that Dell display comes with a miniDP to DP cable.
    Have you tried a different mDP to DP cable?
    (Despite the fact that Dell included a cable, that doesn't prove that the included cable is a good cable. You should at least eliminate that cable as a fault by trying a different cable :cool: )

    Your display has both DP and miniDP connections. You can try a miniDP to miniDP cable.
  18. A4orce84 thread starter macrumors 6502

    Apr 17, 2012
  19. harriska2 macrumors 65816


    Mar 16, 2011
    We have an 2013 iMac with a dead LCD so we are mirroring to another monitor. The mini DP to DP was alway flakey. One day, it just would NOT wake up. This is on El Capitan, not Mojave. So I got a plain old mini DP to HDMI and for some reason, no problems since. Maybe the DP on the monitor is bad?
  20. wave-forms macrumors newbie

    Aug 12, 2014
    Los Angeles, CA
    This may or may not be related to the issue described in this other thread here. You may have tried this, but just in case — have you tried just waiting for quite a bit to see if it wakes up after awhile? I've experienced this issue through an HDMI connection, but after waiting about 20 seconds, my LG monitor goes from "No Signal" to finally waking up. For me, so far I can only recreate the issue when switching back to the Mac mini input on my monitor from a different input after some time. As stated in that other thread, sometimes the issue is different, with a bunch of static appearing for several seconds before waking up.
  21. RPR1000 macrumors newbie


    Dec 29, 2007
    Hampshire, UK
    Its been a long time since this thread was last updated but is there any fix yet? I am having real frustration with this - I boot the Mac Mini up with just the primary, mini-DP port connected monitor switched on and it's fine - then most of the time, but not always, once booted when I turn on the secondary HDMI monitor the primary loses signal and never comes back. And if there are windows open on that monitor I can't get to them etc. etc. it's so frustrating.
  22. Psyence_, Aug 3, 2019
    Last edited: Aug 3, 2019

    Psyence_ macrumors newbie


    Aug 3, 2019
    I have this issue too. Mac mini 2012, connected to a 900x1440 (vertical, if that matters somehow) Asus monitor on the Mac's (1080p limited) HDMI port, and to a 3440x1440 LG ultra-wide monitor (50hz) using a miniDP to DP cable. Almost everyday, sometimes twice a day, the LG monitor will simply turn black and report that it's getting no signal. I have tried a bunch of things. So far, what seems to work the most reliably, and is the less cumbersome possible... is to put the Mac on sleep... and wake it up. At first, it seemed like a perfect solution... but over time, I have come to realize that even this step sometimes needs to be repeated 2-3 times before the Mac mini will actually put itself on SLEEP "the right way". It's like it refuses to put itself on sleep "properly" sometimes... o_O; It may be worth clarifying that the main reason I can afford this in the first place is because the HDMI (actually going through an HDMI to DVI-D cable because the little Asus doesn't have an HDMI input) has been 100% reliable so far. So I can always trust that I'll have a visual interface available to assist me with coercing my Mac into going to sleep... >.>

    Another interesting enough fact I've noticed, is that using this screen setup usually gets me nowhere if I try to access the Apple Internet Restore interface. The display would be so full of garbage that I could barely figure out what I was doing, where I was clicking, the text was messed up, etc. So when I needed to reinstall macOS, I think the only way was to disconnect the LG monitor and do everything over HDMI using a single screen. It's only once the OS was installed that I could get the ultrawide 3440x1440 LG (mostly) back in the game.

    I am also curious to know whether changing from a "miniDP to DP" connection to a "miniDP to HDMI" connection might make any difference. The reason I am hesitating, is that I read a lot of stories on amazon about how few of these adapters are reliable for anything over 2K (to the best of my understanding, my monitor's resolution goes slightly over the normal 2K pixel count, since it is ultrawide). Doing a bit of research on this, I read that the miniDP to HDMI adapter made by Microsoft for the Surface was really good and could output even to 4K solidly, but on the Surface... So... would it work on my Mac mini? I am not sure I feel like spending over 40 dollars to try it out, just to end up with a useless cable I can't find a use for... Although Amazon does accept returns... I'm just so sick of this.

    In the mean time, the moral of the story I guess, is to try *everything* and pray that somewhere on the way, Apple miraculously didn't screw up (they are becoming just as bad as Microsoft was back in the 90s... pretty depressing). The latest thing I am going to try... is to disable the DisplayPort 1.2 option on the LG screen menu (no idea what it does, but it seems useless to me). Who knows... right? It might do something. If it somehow works, I'll let you guys know. What I'm 100% sure of is that this is not my monitor's fault. Apple should just acknowledge and fix the mess.

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21 January 8, 2019