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

I did all of the NV Ram resetting and everything else that apple said to do but nothing changed, and that is why I am here.

Hey Wilber, I had many of the exact same issues as you. Have you tried a short Apple Thunderbolt Cable from your Mac to the back of the display? (thus bypassing using the TB cable that's hardwired into the back of the display.)

Definitively it´s the Thunderbolt cable...... since Mavericks 10.9.2 i have the problem, the TD Display flicker, goes black... etc..... one day works well.... one bad... i connect the TD with my rMBP with the Apple 0.5 meter Thunderbolt cable, and voila, all go well. No flicker, 10/10.

I think that soft have part of this problem, why with pre-Mavericks 10.9.2 all works, and before that i have the flicker problem??.

Well, i don´t know, the question is that with a "external" cable bypass the display thunderbolt cable all works.

Tried the NVRAM, did nothing at all. My TD in plugged in to a 13" MBP Retna. Worked perfectly until the Mavericks 10.9.2. Not sure how this could be a hardware issue if all was working before the update.

This bypass TB cable thing does not make sense. isn't the TB port to the right on the back an input? how can it work as an output bypass?

Why does it take so long to send out a bug fix? I've got work to do and don't have time for this. APPLE! Lets move it...

dukephoto, on the back of the TB display, you'll see 1 TB port - it functions as both an input and output.....for daisy chaining of devices. But it also works as a video input, so try the short .5M Apple TB cable.....it worked for me.

I had the exact same issue as you.....nothing changed with my hardware, but I upgraded to Mavericks, and I started to get the flicker. My theory on this is that Apple made the more recent versions of OS X more sensitive to the changes of the video signal in the longer TB cables, and now we're seeing the video drop in and out based on signal levels/frequencies getting too low. Ultimately, it's a defect in the built-in TB cable in the display, and now OS X is more sensitive to it, and cuts out the video when certain tolerances are reached.

OK, So, I don't have a .5 meter but I did have a 2.0 meter. I figured what the heck. Tried it and it's working. So, the cable length is not the issue. Bummer I now can't use my TB drive but the TD is now working. I wonder if we can daisy-chain a TB drive and display in the sam manner?

Thank you Sir,

DG.

Did the new cable totally solve your problem?

I have exactly the same problem with my Apple Thunderbolt Display (27 inches), the problem started appearing right after I did apply the firmware update V1.2 to the monitor which was made available by Apple last November (my monitor was working flawlessly before applying this firmware update so I am pretty sure there is something wrong with this firmware version and this is the cause of the problem). Does anyone here did apply this firmware as well?

Having the same issue after getting new(er) MBP. On my old MBP I had the issue where the TD would simply go black and act like it wasn't connected. The Firmware update (2.1) seemed to fix that. Then I got a slightly newer MBP (with more ram and storage) and the TD seems to flicker every so often. This seems slightly different than the previous issue though. I made sure that everything was up-to-date as far as firmware goes, and that the connections were solid. I'd love to know what's going on here since the flicker seems very random. I only have one apple keyboard and ethernet running through the TD, nothing else. Any ideas?

Tim

Thanks for posting your solution of using a separate cable.

I just wanted to confirm that this also worked for me. Unfortunately I only saw the thread after taking my 4 year old TB screen in to Apple in Cambridge UK, and for them to diagnose the problem as a faulty backlight board. They said this was attached to the display, so I would need a new display costing £640. They only offered a 90 day warranty.

So I declined, and bought a new screen (at a £100 discount) to get a longer warranty. Having reclaimed the old screen I saw your post and purchased a new TB cable to try. It has been working faultlessly since, now for a period of 8 weeks. I use the captive lead as a power supply, and use the new TB lead between my MBA (2012 vintage) and the screen.