Q: 27'' LED Cinema Display flickers when powering MBP and dimmed down

The first step is to call Apple. I was told to unplug my display and reset the SMC on my MacBook Pro. If the problem recurred after that, the tech support agent informed me that a repair would be in order.

I can confirm I also suffer from this problem, but only since I have acquired a mid 2011 MacBook Air. It flickers at low brightness settings. Didn't do that with my three previous Apple laptops (all three being 2010 models). For the record, I have an Apple LED Cinema Display 27", and had the ACD 24" the year before, never encountered this issue.

Could it be related to the Intel GPU?

Regards,

Dr Sly

I was at the apple store yesterday playing with a 27" cinema display and was not able to reproduce the problem.  Clearly it was warm from being on all day, plugged it in with it's magsafe, lowered the brightness, zoomed the doc with rollover as some mentioned on this thread and nada.  It worked so good, I convinced myself it's right for my needs.

Hello Mike,

of course it will be hard to replicate, the Genius Bar at the Apple Store is as alien as possible from the original conditions one encounters at home: it's darn bright, it's got AC so high to give you hard nips, and bottom line, it's just not a place where you can spend significant time testing various settings (15 minutes 'interviews' at the Genius bar?)

Here are the facts as far as I am concerned:

- I never had this problem before with ACD 24" and current ACD 27"

- it just started as soon as I used the MacBook Air from July 2011 *never once before*

- it can't be related to Lion because I have been testing it since February on three different laptops from 2010

- PRAM and SMC resets don't do anything

- I have a clean install

- firmwares and drivers all up to date

- the previous MacBooks all had different video cards interacting with the 27" ACD (i.e., NVIDIA)

So now, let's deal with conjectures:

- if it's hardware? Could be video card (Intel HD Graphics 3000 GPU), or Thunderbolt port

- if it's software? Err, well, drivers of some sorts? Firmware controlling the abovementioned hardware?

- could it be that every other MacBook replacements they would offer me would do the same thing?If this is the case, than I think it's better/easier/cheaper to replace the ACD than the computer...

To all the people saying a firmware/software patch will eventually come: yes, of course it might, and I would appreciate that. But when you pay a premium for a brand with this kind of rep, you want to obtain the goods/services *now*, not x months later...

Yep, I agree with your assessments.  I was actually on my own to the side where hte Mac Pro are situated but I agree too many variables to property assess.  I did have my MacBook Air 2011 with me and couldn't reproduce it so it's plausible Apple may have a hard time reproducing it too although many on the forums are able to reproduce it seems.

It's quite irritating! I'm pondering whether I should bother bringing all this hardware to the Apple Store (would be heavy and cumbersome) if it's going to be such a hard time reproducing the issue... I'll probably meet a 'Genius' beforehand just to spare me the trouble.

I forgot to mention that, just like an issue I have been experiencing with my iPad 1st-gen (a weird coincidence), the ACD 27" has never been successful at adapting it's brightness based on ambient light. Never. Only manual adjustments (I can't remember for the ACD 24" before this, so I won't comment on that one).

This is completely different from my experience of all of my Apple laptops to date (14 of them!) and my iPhones (a few of them), which all have a perfectly adequate ambient light sensor. I don't know if this has anything to do with the low-light flicker of the ACD 27", but I figured I might as well mention it for record-keeping purposes.

Peace out.

Dr Sly

I don't think that a hardware/firmware patch will come because it seems to have something to do with the power supply and graphics load. And yes, the problem would be hard to reproduce in an Apple Store (Mike95 wasn't using a 27" ACD with a confirmed problem). As someone has already noted, it helps to be using a graphics-intensive app, one that would cause the discrete graphics card to be used (which can be verified using the freeware utility gfxCardStatus), such as iPhoto.

When I called Apple Support yesterday, they were ready to schedule a repair. Has anyone sent their display in for a repair -- and had the problem fixed?

I fear that this might be a design flaw

I'll schedule a meeting and report back here after I have obtained feedback from our benevolent Geniuses.

Cheers,

Dr Sly

This sounds great; I would love to hear the results as I'm holding off on buying mine for this as well as the unknown concerns of the thunderbolt 27" with bootcamp campatibility

Has anyone installed the new EFI firmware version 2.1 for the MBA with Thunderbolt in conjunction with the ACD 24" and/or 27" yet?

I was wondering if that fixes the issue. As soon as I get home, I'll try that.

I have same problem ...

... But not from the start, after a cuple weeks .

MacBook Pro 13 2.7 i7 with ACD 27 (not thanderbolt).

Same issue....flickering and sometimes crazy vsync issues

Macbook pro 13 2.7 i7 with ACD 24

Same problem here: 27" Cinema Display on a Mac Pro with ATI 4870 HD videocard. Display flashes and blinks once a minute. Very annoying!

It seems like there's some interference in the cables, but I'm not quite sure. I've got a Belkin extension cable which I thought was causing trouble. I've reconnected the cables a couple of times without succes, but then figured out that the USB 2.0 or the magsafe powercable is interfering with something. I ducktaped the loose magsafe cable and now the blinking seems to have almost stopped. Just once in a while instead of every few seconds.. :/

I plug out the magsafe of Apple Cinema Display and I plug again the mag safe of MacBookPro !!!

  This is it !!!

Fix it the problem !!!

Thanks,

Stefanos.