27" Cinema display turns off randomly

This is happening to me as well. I have a new 27'' Cinema display and a new Macbook Pro (early 2011) and in clamshell mode the power on the monitor will shut off randomly. This happens only after the computer has been left idle in sleep mode so far. What's weird is that the power on the monitor completely shuts off so that it's not charging the laptop or anything. The only solution is to unplug the monitor and plug it back in. My only two thoughts are that this is a settings issue (though that would be a weird setting) or that the monitor may have an issue. Though, I think it would nearly impossible to replicate at an Apple Store since it appears to be random. Any ideas about what this could be?

Looks like there is an idiosyncracy between the Video PCB ( I have a Radeon HD 5770) and Apple's 27" LED Cinema Display. For me the dreaded "Blackout" only occurs when I connect two (2) 27" Apple LED Cinema Displays to my 2006 Mac Pro 1,1. BTW my Mac Pro has upgraded Intel x5365 CPU chips. So instead of being 2 "Dual Cores at 3GHz" it is now 8 Cores at 3GHz.

Yes, it basically makes the USB function STOP or appear to stop and hence a full power down and reboot to get it back up.

WHAT I FOUND

For me when I reduce the resolution of one of the displays to just under the full resolution spec of 2560x1440, so in other words I set the one 27" LED Apple Cinema Display to 2048x1152 and once I did this, both monitors and the computuer operates normally. Also note that before I connected the 2nd Apple 27" LED Cinema Display, I had a Dell 2407 24" Monitor connected to the DVI port and of course it's resolution is nowhere near what the Apple LED Cinema Display can do, but with just one Apple LED Display and the Dell connected I never so much experienced any lockups, blackouts, wake up issues, etc.

So it is a resolution problem that seems to be driving the screen blackout. I will see later today after my system sits idle for a few hours if I have any problems getting the system to wake up with the slightly lowered screen resolution on one of my ACD LED monitors.

Again, it appears to be the Radeon HD 5770 because I read where a person with a 2010 Mac 5,1 with dual 2.4GHZ Wesmere CPU's was having the same problem. OR it is the LED Display that has some sort of timing issue when 2 of them are connected to the Mini Display Ports.

APPLE we NEED some HELP here.

For the mac pros there's one thing I suggest you check. With the cover off, when you boot your mac pro, look at the video card and see if its fan is running. You will (eventually) get a thermal cutoff if the fan isn't running. You might also check periodically even if the card's fan was running at boot to see if it stops. A little "tweak" with your finger will get it going again.

I'm basing this on my experience with a 5870 where the fan couldn't always overcome its starting friction and the card would overheat within a few (random) minutes causing my machine to shut off (with the exception of a single exhaust fan). Replacing the card fixed my problem.

I'm not precluding that there could be something wrong with the monitor or some "quirk" using a 5x70 on an unsupported machine. I'm only mentioning my problem and something to possibly look out for.

Since adjusting the screen resolution down from maximum by just one notch on just one of my new Apple LED Cinema Displays, my computer is back to normal. I also have the USB disconnected from the same monitor I have the reduced resolution setting. The monitor with the reduced resolution is the 27" LED Cinema Display that I purchased just yesterday. So far I have had about 3 -4 hours of normal operation with the lower resolution setting on this new monitor.

If this lasts through the night, I will go back to the max resolution setting on this new monitor, because anything less than max resolution looks very poor on this LED display. I will also keep an eye on the fan as you suggest. I'll soon know if this isolates the failure mechanism.

Made it through the night with reduced resolution on my newest 27" Apple LED Cinema Display. So now I will adjust the monitor back to full native resolution, which by the way is a must for this LED monitor. If this fails again, which it most likely will, then back to Apple.

I checked the Radeon HD 5770 Apple Video Card and the fan works fine.

Set resolution on new ACD LED Monitor to full Resolution 2560x1440 and within an hour My Windows Partition (VMWare Fusion - 32 bit Windows XP- Been running for 3 years with no problems) froze up. By this I mean my displays maintained the video information, but I was unable to move my mouse so it appeared my USB Bluetooth receiver was not working. This receiver was plugged into the back of the slightly older 27" LED ACD. The mouse pointer was stuck over the VMWare Fusion partition. So I opened the side cover and the fan on the Radeon HD 5770 video pcb was running. I then unplugged the older 27" LED Apple Cinema Display and the video information from that display showed up on the other monitor. Then when I plugged the older monitor back in, I was able to get my mouse to work. Boy this is screwy.

I have NEVER had any issues with my 2006 Mac Pro 1,1. It has been like a rock. Last month I upgraded to the Apple Radeon HD 5770. The upgrade went PERFECT and the Radeon HD 5770 worked completely normal with my Dell 2407 24" monitor. I already had the referb'd Apple 27" Monitor in my house waiting to go, so the next thing I did was hook up the ACD. That went perfect. Then I said, let me try going DUAL DISPLAYS (actually I never did this before), and walla, that worked perfect. I then ran the 2 monitors (ACD LED and DELL 2407) hooked to my new Radeon HD 5770 for 3-4 weeks and no problems at all - perfect. Then because I loved the display quality I purchased a 2nd Apple LED 27" Display and that is when the $hit hit the fan.

BTW I am running WD 2TB SATA II 7200RPM BLACK hard drives for Mac OS and Windows OS. You know it is times like these that I wonder how a software RAID would hold up.

I did read that another person had the same problem on a 2010 Mac Pro 5,1 2.4GHz 8 core. So if that is the case, then this problem is most likely going to be in the 27" LED Cinema Display Monitor itself. I mean if a 2010 Model can repeat what I am seeing, then common link in all this is the ACD.

I bought in November 2010 a MacPro with the ATI 5770 and a Cinema Display 27. At the first boot the Cinema Display worked just fine. After a little while it started to turn off while I was working at the machine and also did not come back easily. By now I had the ATI replaced and they replaced the power supply and the logic board of the display. Unfortunately the problem is still existent. Apple denies to replace the display. It has to be repaired again, which means I cannot use my MacPro for some more weeks. They tried to sell me the protection plan but it feels like I would have to pay for a possible faulty production by apple. That doesn't appear to be right.

I just hope that one day the MacPro will just work with the Cinema so I can stop to regret to have spend so much money on a machine configuration I cannot rely on ...

Methods I tried to get the display working again, which in the end all failed. Some where like a temporary fix:

- Switching the graphic adapter to a different PCI-E port

- Having the graphic adapter replaced

- Switching the Mini Display port used at the graphic adaptor

- New installation

- Disconnet and reconnect power/USB/Display port

- Using a MacBook Pro to bring back the Cinema Display to life (it always works with the MacBook Pro; at least after reboot)

- Paramter Reset

- New power supply in Cinema Display

- New logic board in Cinema Display

I had this issue fixed. After replacing the graphics adapter in the mac pro and replacing the logic board and power control in the cinema display, they realized that simply the cinema display cable was broken. Since they replaced it everything works perfect.

I am having the same/similar issue. I bought a 27 inch LED cinema display in 2010. It broke in 2011 (same exact issue). Apple replaced it. here it is, just over 12 months later and it's having the same issue AGAIN. Apple now is saying they won't replace/repair/troubleshoot it without me paying for it.

I have a mid-2009 Mac book pro 15" plugged into a 27" cinema display. I notice the same kind of issue. Unplugging it and then plugging it back in usually solves the issue, but often only for another 15 minutes or so. Now the issue has become worse. When the screen "blacks out" the led indicator on the magsafe power cord to the laptop also goes out. It seems to me that this is some kind of internal power regulation issue in the display. I did some searching and it does seem like its the internal power supply. I found a replacement internal power supply board at http://www.cwioutlet.com/APPLE-661-5543-POWER/Parts/Apple-Parts/Apple-p9631535.h tml. I haven't bought it, but am clost to ordering it since apple is refusing to cover this anyway.

Thanks for sharing, this was the exact issue that was causing the shut-off problem. Unfortunately, CWI Outlet doesn't carry the part anymore, but you can find it here as well: http://www.dvwarehouse.com/Apple-Power-Supply-250W-for-LED-Cinema-Display-27-614 -0487-661-5543---NEW-p-38212.html

Hopefully, this will help someone else in the future.

BTW - it was really simple to open up the display and replace the power regulator. Pop off the screen, unscrew 12 screws along the edges (only the ones with the star-screws) and pop out the display assembly. Move the display assembly off to the side and remove the power regulator (3 cables) and put it back together. Really, that's it.

Message was edited by: PeterSD