27" Cinema display turns off randomly

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

This has happened to me as well. I now have had 2 go bad. The first I took back to the apple store only to have them tell me that it wasnt repariable and was out of warranty. So... I bought a new one and now about 2 years later this one is doing it too. I replaced the power supply today ($250) and still have the problem. Anyone get this fixed without changing the resolution of the display? I didnt pay top dollar for a monitor to use it at less then native resolution.

I had the same problem. The 27" Cinema Display would turn off automatically after 5-10 minutes. On turning the power off and then on again, it would come back on - if not at the first try, then at least on the second or third attempt. Additionally, sometimes the display brightness would fall significantly sometime after the display had come back on. But if the display brightness did fall, the monitor would stay on thereafter and work without any problem for the whole session! Now every time I sat in front of the computer I started wishing that the display brightness would automatically fall. This went on for a year, and out of frustration I was almost on the verge of sending it back to Apple for recycling.

Then only a couple of days ago I found that if I turned off the auto-brightness setting and manually decreased the brightness to about 3/4th the full value, then the monitor would stay on and never turn off automatically! It has only been a couple of days, but I haven't had the display turn off automatically since. Maybe this can solve the problem for some - if of course working with the reduced brightness is an option.

It seems that while the problems people in the forum are reporting are very similar, they are not exactly the same. For example, in my case reconnecting the mini-display port won't have any effect, and I haven't seen anyone else in the forum reporting an automatic drop in brightness. So don't get your hopes up, but do try manually setting the brightness to a lower value once and then see if the problem persists. I have visited this thread many times in the last year looking for hope and help. I hope this trick help you. Thanks!

Took mine to Apple. They replaced power supply and some other logic board component. Worked better for a while. Problem came back. Then, once I eliminated the use of a surge protector the problem went away for an extended period of time. But the issue is now present again. Won't easily come back on after power cycling. Used a power cycle would help. Annoying. This is clearly a known defect based on numerous reports here and other support threads. Mine is still under Apple Care. Going to politely demand a new Display at this point. Last time I was without it 5 days while they worked on it.

It works! Not shure, if the hard-plug-out after the new brightness setting has influenced the result. Today in the morning I turned on my Mac Mini, which is connected to the LED Cinema Display and it turned of after about 10 Minutes by itself as the last few days ago. Than I found the fix here. So I connected to the mac through Teamviewer, I changed the brightness-settings as mentioned and I restarted the display by just plugging it out and in. Now it works fine. THANKS A LOT!!!!

This is what worked for me:

The touch-sensitive power and brightness buttons on the side were randomly self-activating, causing the screen to dim, brighten, and shut itself on/off. I disabled these buttons through the display control panel. Now the screen stays on. This also disables the brightness function keys on the keyboard so I just have to use the control panel to adjust brightness, which is a little bit of a pain.