New 27" Thunderbolt Display Flickers when attached to new 27" iMac

Update II: Upgraded to nMP (4c/512/D300), which according to specs I saw online, has 3 thunderbolt busses split over 6 ports. I have each display and the GRaid drive plugged into seperate busses, so 3 of the 6 ports are used. No issues whatsoever, screen flicker or audio. This is consistent with the testing on my cMBP 13 and the Apple Store's in-house cMBP 13 and rMBP 13, that plugging the items in seperate ports alleviated the problem in my instance. Given the number of ports I now have available, I will hopefully be able to avoid daisy-chaining thunderbolt devices for the time-being.

My work purchased a new MBP 17" and the 27" Thunderbolt display for me last year and I've been experiencing the same flickering. By the time my IT department got the computer and display to me, the display warranty period was over. One day it was so bad I couldn't use it so I called Apple - I had to pay for the call and it was too late to return it but Tech support had me run through a few set up parameters and it stopped flickering at the time. It eventually started flickering again and has gotten more frequent again. Apple never said anything about it being widespread and it was only when I started looking on line that I ran into all the complaints on the forum. Unplugging and replugging it in does seem to stop the flickering - but what kind of fix is that?

oh and my MBP is Retina with only 8GB RAM

One thing I noticed is that when i'm video chatting i can still hear audio when the screen flickers. Mine has never shut off completely, however it flickers every 30min.

I have a brand new 16GB MBP 13" connected to a brand new 27" thunderbolt.

I have had the same issue...and fix.

MBPR with new 27" Thunderbolt screen flickering, turning black, disconnecting. I have tried everything in this thread and others.

I removed the all in one thunderbolt connector from my laptop and installed a new Apple Thunderbolt cable from laptop to the 27" display Thunderbolt port on back. I have had ZERO issues now for a month.

I use the all in one cable to power my MBPR but use the seperate Thunderbolt cable for the display. Seems like the 27" Thunderbolt Display all in one cable has sheildning or manufacturing deffects. ***** having 2 cables but great to finally use my display!

I'm sure you could keep swapping displays unitl you find one with a good cable but the seperate cable worked for me.

Same here. MacBook Pro. Thunderbolt display. And Belkin Thunderbolt Express Dock. The display started flickering shortly after I purchased it. Had it replaced in warranty. Now what complicates this is that I added the Express Dock and started to experience a number of weird problems, such as outboard USB 3 drives just disconnecting for no apparent reason, and intermittent MacBook crashes. It took me a long time to troubleshoot. Finally I just bypassed the Thunderbolt monitor cable altogether. I used external Thunderbolt cables to connect from my MacBook to the Express Dock and then from the Express Dock to the monitor. Everything has worked great since (several months now). While I was setting up the new configuration, just out of curisoity I retried hooking up the monitor with its cable to the laptop. Sure enough, after just a few minutes the monitor started flickering. Cost me a hundred bucks for the two cables but fixed the problem. I was going to read the riot act to Apple, but decided not to waste my time. I've already wasted hours on this. Besides, I don't think they're listening. If they were, they'd bring all their production back to the USA where there would be some real quality control (For the money Apple charges for their products, there is no reason they can't be manufactured here.).

I've personally spent about 400 miles of driving back and forth to my closest Apple Store, hours and hours of time, and multiple repairs on this issue. I then replaced all of my hardware! Add that to the various threads on this topic that total over about 500,000 views, and it's clear there's an issue here. I'll try to keep this post pithy, with the facts here at the top.

This problem started with a 1.5 year old 15" Retina MacBook Pro and Thunderbolt Display. I now have a brand new Apple Thunderbolt Display AND brand new 15" MacBook Pro - AND HAVE THE SAME FLICKERING PROBLEM!

Steps Taken

1. Many, many phone calls to AppleCare. No clear "yes we've seen this before and know how to fix" type of response.
2. Many visits to the closest repair facility to me, which is the Genius Bar at an Apple Retail store. Again, I worked with about a half a dozen people there, and no one reported "yes, we've seen this and know how to fix this.".
3. After replacing the LED panel, I drove 40 miles back home, plugged in the display, and it was totally dead.
4. After driving BACK to the Apple Store, they told me they would have to try another repair. As I was leaving, the Manager asked me if I was okay, I explained my issue, and in an awesome show of understanding, he replaced my display right there.
5. I took a brand new Thunderbolt Display home, and I STILL had the flicker problem.
6. In a second act of desperation, I bought a BRAND NEW 15" Retina MacBook Pro!! (going to sell my 2012 model to a friend)

After ALL of this, I'm sitting here with 100% new Apple hardware and the display still flickers! This is maddening. I've made no OS X setting changes. Everything is 100% factory default new, and my Thunderbolt Display has flickered about 20 times, and is now totally dark. (as I've typed this) Other Notes

• A very basic setup. Just my 15" MacBook Pro and Thunderbolt Display. I keep the Mac lid open and use both screens in extended mode.
• My MacBook Pro resolution is set to "scaled" at the "looks like 1680 x 1050" option. But I've tried the recommended option as well.
• I've replaced the MagSafe connector. (I've read some posts that a bad connector was the theoretical culprit)
• Display flickers and goes dark, but the USB ports still work. (I have a wired Apple USB keyboard plugged into it.)
• The display resolution settings are factory default.
• I've tried adjusting brightness settings, spaces settings, and arrangement settings. Nothing works.
• I've tried Apple's recommended SMC reset and PMU reset procedures. No changes.
• This all started when I upgraded to Mavericks. I really think this could be the issue.

Anyone have any other thoughts??!?!? Am I missing something?!?!?

Power supply? What condition is the electrical supply to your home in? Does it suffer from radio interferience? You might need to check with a local electrician or your council about the state of the electrical supply. you may need a conditioner to stop any irratic power behaviour.

Another concern might be a stronge radio signal interferance aor other electrical devices plugged in on the same power circuit. THings like a fridge, a freezer, a radio device, or it might even be something outside your home, like an electrical trasformer, and telocomunications street node giving off radio signals and things like that.

Apart from those sorts of things you might also like to see how the power brick on the display and cables are doing? Try moving your display away from the walls in case there is magnetic interferance from power cables in the walls.

Have you tried to set the display u somewhere elese away from your home to see what if that stops any anoying electro-magnetic interferance.

Hi Everyone,

About 3 / 4 months ago I posted on this thread about a problem that I had with my MBPR 15" with 27" Thunderbolt Display.

I'll make it very short. For me, it turns out having my iphone near the monitor was the issue all along. It produced flickering and eventually turned off my monitor.

Note: The phone only induced the screen flicker while in GPRS mode. I.e when 3G coverage is not available. I guess this has to do with RF interference.

This is what I suggest you try:

- Take your phone and turn off 3G so you get a GPRS data signal instead and play around with the location / proximity of your device to your monitor and see if it produces the flickering.

Let me know if you have any luck.

I purchased the 0.5M Apple Thuderbolt cable, connected it from my MBP to the display, and am now 2 days running with no issues.

So in my case (which has been extensively tested), bypassing the built in cable fixed the issue.

I'm still going to take the display to Apple though, as the integrated TB display cable should work. Especially for a $1,000 display.

fchristensen : Hello, I´m experiencing the same issue, I would like to know about your MBP hardware, RAM for example.

Thks my friend I'm going to try that solution.

Regards

Hello Guys, It seems to be a memory issue. I have a MBP 13'' 4GB RAM 10.7.5, and I expanded this RAM to 8GB since then my TBD experienced this annoying flickering. After I made a downgrade to 6GB the flickering disappeared.

ruslantagirov wrote:

I have MBPro 8.1 (early 2011) which I've upgraded recently to 16Gb

and Thunderbolt Display

It started flickering sometimes, same problem as described by many in this topic.

I've tried resetting NVRAM - doesn't help.

It seems the problem is somehow related to mac os memory management and tb video adaptor's memory manaagement.

Hi guys.

It seems my problem disappeared after upgrading to OSX 10.9.2

I've also have updated HDD to the new one, but don't beleive it could affect the flickering.

hey guys,

I don't know if this thread is still open or not but I have the same problem with my 13 inch macbook pro and 27" TBD. I called apple and they said they knew nothing about the problem and I told him it had been going on for three years. He said he would look into it and told me to take to an apple store. i will update on that when I do that. By the way I am running OSX 10.10 beta with 8gb of RAM.

Have you tried the NVRAM reset procedure?

Try resetting NVRAM as described in this article: About NVRAM and PRAM

Resetting NVRAM / PRAM

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on the computer.
4. Press and hold the Command-Option-P-R keys before the gray screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys.

As I stated above, I totally got rid of the 'flickering' issue with my home Thunderbolt display after updating to Mavericks 10.9.2.

Now i'm on 10.9.4 and all works fine.

But recently I brought the laptop to my office and connected the other LCD monitor via Apple Displayport-DVI adaptor (which is fine with Thunderbolt port on my MBPro 8,1).

And the display eventually started flickering, it was like my laptop tried to constantly change the LCD's resolution.

I've proceed the NVRAM reset procedure and the problem disappeared.

I've been working on this laptop with this LCD the whole previous week — no flickering or other display related problems.

Now I'm at my home setup again, and still no problem.

Please, let us know if the NVRAM reset helps you.