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reid007 Level 1 Level 1
Just bought a brand new 24" iMac and matching 24" LED Cinema display. Clean 10.6 installation out of the box. Day one, everything working ok except if I let the system sleep for a while the iMac will wake up if a key is pressed or mouse moved, but the display will not. No problem if its been asleep for a few minutes or even half an hour but leave it say 6 hours (say I'm downloading something overnight) and I get this problem. It will work again if I reboot the iMac or disconnect the display's power though just disconecting the display from the iMac display port doesn't seem to fix it.

Has anyone got any ideas? Apple tech support had nothing except suggesting resetting the PRAM. At the time I wasn't aware the problem was only happening after an extended period of sleep so I thought it was fixed but its clearly still there. Help!


iMac 24", Mac OS X (10.6.1), 24" LED cinema Display
  • alpa Level 1 Level 1
    This is a 'me too' reply. I see the same problem with my 24" iMac with an older 20" cinema display with a mini-DP to DVI adaptor. The 'Detect Display' function still detects the external display but will not wake it up from sleep. Plugging in and un-plug the external display does not help. The only way to get it working again is to reboot the iMac.

    Sorry, no solution from me, just another fellow frustrated user.
  • Raphael Davison Level 2 Level 2
    Me too, too. Any news on this?
  • manic Level 1 Level 1
    Hate to be another "me too" but me too on this issue! I've got a 24" Cinema display that I have connected to a Mac Pro via a mini-dp to DVI adapter from Atona Technologies. ered-p-17922.html
    I thought that the issue might be from using this adapter, but it sounds like you guys are having very similar problems as well.
    Will keep searching for a solution.
  • nunec6 Level 1 Level 1
    This is another me too. only now its not waking up when restarting. I also have it converted but its not the same converter as the one posted above
  • ChoreoGraphics Level 2 Level 2
    I am really not convinced that this is a "display" problem in and of itself now since I have seen scores of posts throughout the Apple Forums with various Macs and Displays that complain of the same symptom.

    I have been chasing this problem now for 3 months (looks like it started for some people going back to at least September 2009). I have (3) identical SONY 23" CRTs connected to my Mac Pro via two PCI video cards, but I am having trouble with only ONE monitor so far (doing the same thing you describe in previous posts - won't wake up from a long sleep - a few hours).

    • First I purchased a new monitor cable for the monitor in question - no change
    • Next, I purchased a new VGA to DVI Apple Adapter - no change
    • Next, after talking to AppleCare Tech support and trying SMC reset, PRAM reset, etc. they sent me a NEW ATI 2600 video card - installed new card - no change
    • Tried swapping suspect monitor to connection on other card (known good card) - same monitor would not wake up!!!
    • Purchased new GT-120 video card to replace the new ATI-2600 - same problem.

    This leads me to believe that it is either a problem with the OS somehow or perhaps some monitors just need a stronger signal to wake up??? Maybe my 3rd monitor is just getting tired compared to the other two and need a bigger kick to wake up?? Maybe some of these new flat screen LCD/LEDs need that extra kick out of the box?.

    All I know is that I have seen scores of complaints on this issue all over these forums with different Macs, Different types of displays (new and old) and various video cards - the only common denominator I can find is the OS.

    Message was edited by: ChoreoGraphics

    Message was edited by: ChoreoGraphics
  • xvx29a Level 1 Level 1
    I was just having this issue myself and after going through a ton of thread I was able to solve my issue.

    I installed Snow Leopard 10.6.0 and did the combo update to 10.6.2 and started having monitor issues. The display would not wake after sleep, and on reboot the display would still not awaken. I could still connect with Screen Sharing. The display would eventually start if I unplugged the display power and the connection to the video card and once the Mac Pro booted into 10.6.2 I could reconnect and the display would turn on, sometimes.

    If you have similar issues what seemed to work for me was a SMC reset,

    This resets the management control and seems to get the display to start responding again.

    To reset the SMC:

    1. Power Off The Mac Pro
    2. Unplug the power from the back of the machine
    3. Hold down the power button for 5 seconds
    4. Plug in the power.
    5. Hit the power button and it should work.

    I hope this works for some people that may be having this issue.

    Good luck.
  • xvx29a Level 1 Level 1
    This no longer works for me, and now I can't get the monitor to Apple Cinema Display to turn on at all after 10.6.3 update.
  • RichMBP Level 1 Level 1
    Same issue after 10.6.3, i can see the main external display but the MB Pro display can't be detected
  • Pete1961 Level 1 Level 1
    This may sound strange but after trying many things to fix this same problem I was able to wake my monitor by changing where it is plugged into my power strip. Seems a little strange but after a couple of SMC resets not helping, re-boots, etc. this actually did the trick!
  • KAI51 Level 1 Level 1
    I have a 23" display that is about 3 years old that is connected to a Mini that is about 4 years old. Software has been upgraded through the years to the current 10.6.4. My display would not wake from a long sleep. Everything everybody else has tried I did (unplugging and reconnecting, resetting PRAM, etc. etc.) would fix it for a while but eventually they no longer worked. Long story short after taking the display in and having it "fail" to wake during testing in an Apple store I sent the display back for repair. Approximately $400 and four days to replace an internal inverter (I think that was what they did) and the display has been working perfectly for the last few of months.
  • Justin Faceless Level 1 Level 1
    Ok so i too have had this issue, i tried all the suggestions on here with zero results...
    The last three times i had this happen i did the following and it worked all three times:

    1- Leave computer on
    2- Unplug the monitor from the computer AND the power from its plug
    3- Let monitor stay completely unplugged for roughly 15-30 min
    4- First plug monitor into the computer then plug in the power

    I noticed different results from different peoples setups... i'm merely
    throwing in what has worked for me in hopes of helping another person
    with this same issue..

    Good Luck !
  • dharmaman Level 1 Level 1
    Same problem. I'm using the Gefen DVI to mini-display port adaptor and have started experiencing the problem where the 24 inch CD goes to sleep and never wakes up. It used to be that rebooting solved the problem, but now that doesn't work either.

    Is this a problem with these displays and should I return mine? I thought it was the Gefen, but now suspect the Apple display.

  • Vuvuzella Level 1 Level 1
    I had this problem. Just turn off your sleep mode. When you leave the computer, switch your display off at the side.
    I have found the solution to the 23″ cinema screen not coming on when you start up. I had this problem for years. If there was a power failure or I switched my computer off, on start up the monitors would not light up. After reading countless blogs and taking the power cable in and out of the brick until it came on, I tried this. I have a high powered torch which I held on the brick for a minute or so, just enough to make it warm. It worked. Tried it on the brick for the second monitor and it worked. It has done ever since. 1st time, every time. I think that when the brick is cold, it doesn’t work properly. Just try warming it up. (NOT IN THE MICROWAVE!)
  • patwl Level 1 Level 1
    I also have the same problem. I have found an odd "solution".

    The problem first arose when I bought a new 20 inch display for an old G5, running the latest OS 10.5.8. It is a very mysterious problem.

    Anyway, my "solution" is to temporarily swap displays (using the screen my MacPro - a 24inch). This has immediately fixed the problem every time.

    But it's very much less than an ideal solution: the only reason I brought the G5 in to my work where the MacPro is, was to test whether the problem was with the display or the G5.

    Any thoughts?
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