Q: Screen Flicker with External Monitor

Finally some good news!

So a mini DisplayPort to Dual-Link DVI adapter + Dual-Link DVI to HDMI cable is what you used? Or does your monitor have a DVI input? I'm using a TV so it has to be HDMI on the other end.

At least it's a temporary solution I suppose.

Hmm I wonder what the problem could be... I guess the Dual Link cable somehow filters out the problem. Hopefully Apple fixes this soon.

POSSIBLE SOLUTION.  I just got off the phone with AppleCare, and the issue has been solved for me.  I will now share that information with the rest of you in the hope that it solves the problem for you as well.  UPDATE: Crap, I just finished writing this and the flickering has started again.  Oh well, you can read what I was instructed to do just the same. 

• Open Finder
• Click on your Hard Drive (Default is Macintosh HD)
• Open Library
• Open Preferences (NOT PreferencePanes)
• Click and drag the file "com.apple.windowserver.plist" to your desktop (Do not delete in case you want to restore the file if this doesn't work.  I was told that it would be regenerated anyway, but was also instructed not to delete it until I really wanted it gone.
• Click on your home icon under places in the left side of the finder window
• Open Library
• Open Preferences (NOT PreferencePanes)
• Open ByHost
• Move any entry you have that starts with "com.apple.windowserver" to your desktop. It will be followed by a string of numbers and letters, and I was told that there may be more than one that starts with that prefix.
• Shut down your system
• Reset your PRAM by pressing the power button and then IMMEDIATELY pressing the Command, Option, P &R keys and holding them down until you hear your system chime twice, and then release. 

Hopefully this will resolve your issue.  If it has, then just delete the files you drug to your desktop.

Just tried the Possible Solution by "later2day".  Its only been a few minutes, but NO FLICKER or Jolts, or Blank Screens!!!! 

I didn't have the "com.apple.windowserver.plist" but I did have references in the ByHost folder. 

I deleted the "com.apple.windowserver" refs in the ByHost.  Shut down and rebooted using the key commands.  I didn't hear a beep on my iMac, but it reset and restarted. 

I would have noticed at least a couple of flickers during the time it took to write this so I think this IS A SOLUTION! YAY!!!!

The fix reported by later2day worked for me. Not only it fixed the flickering problem (external Samsung SynMaster 204B with DVI mini-display adaptor) but it also seemed to have fixed the resolution problem that I had, i.e.: the screen's resolution is back to its original crisp 1600x1200 60Hz. Thanks!

Update (2 mn. later). Flickering is back, although limited to bottom 1/16th of the screen. Still needs some work I suppose.

Has anyone upgraded to OSX Lion to see if that solves the issue?

Hi,

I updated to Lion...and the the problem still persists

I didnt try the preferences thing mentioned by "later2day" yet.

I will test it and let u know, if it works.

I tried the fix by later2day and it didn't fix the problem for me.  Still on SL by the way.

:-(

Hi Allison,

I tried the fix by later2day on lion!

It doesnt work!!  I hope apple comes out with a fix soon

As an update to the fix, I have found that the VGA adapter still gives me problems, but with an HDMI adapter I am able to use my external screen with no difficulties what so ever after the fix was implimented.  I am using Lion with it, and have no problem since the upgrade either. 

VGA is screwed though, and I am sure it is a Thunderbolt port issue as I have tried more than one cable and VGA adapter. 

And finally it works for me!

Okie I would like to explain what all things I have tried.

Mac configuration:

Mac book pro 13 inch i7 (Early 2011).

ASUS VE228H LED Monitor

Interfaces Experimented:

1. MDP - HDMI - HDMI - HDMI

Doesnt work

OS Tests:

1. Snow Leopard with Thunderbolt update of June 27th - Doesnt work

2. Migration to Lion - Doesnt work

3. Windows 7 Professional via Boot camp - doesnt work

4. Preferences / PRAM setup - doesnt help (but it got better sometimes)

Got sick of the above tests and after wasting more than 18 hrs on this, I made a final try and it worked.

2. MDP - Dual link DVID - Dual link DVID - Dual link DVID

It works like a charm

Conclusion:

I spent 1500$ on my first apple laptop, I felt may be I should spend more 100$ to try out this Dual Link DVI interface. Here is the price list for this DVID stuff

MDP - DVID   - 350 SEK / 29 USD

DVID - DVID   - 250 SEK / 15 USD

Abreviations:

MDP - Mini DVI port

DVI   - Digital Video Interface

HDMI - High Definition Media Interface

DVID - Digital Video Interface Dual link

Isn't it a Mini DisplayPort?

Hmmmm I'm using a TV in my setup so it doesn't have a DVI port, but I already have a a Dual-Link DVI to HDMI cable that I used to use with my old MacBook Pro.

Perhaps if I bought a mini DisplayPort to Dual-Link DVI adapter and used that cable mentioned above it may work. I've been using a mini DisplayPort to HDMI cable without success.

yep!! its a Mini display port

I dunno guys, it really irritates me to think that we have to buy a cable to make the $3000 investment we've made work again.  I'm not doing it.  Planning to escalate in Apple service.  I'm sick of this!  and I don't often get this mad.

Allison Sheridan

NosillaCast Podcast at http://podfeet.com

A technology geek podcast with an EVER so slight Macintosh bias!

Follow me at http://twitter.com/podfeet

You're right Allison, we shouldn't need to be buying extra things to get something that already worked fine to work properly again.

Plus I really want a "pure" solution with 1 cable, withou adapters. That's why I bought the mDP - HDMI cable in the first place and that was a good $50.

I've already called without any luck and I've had the same result at the Genuis Bar. I've also submitted bug reports to Apple via their feedback pages.

How can we escalate this further?

I just bought the new mac mini with lion and i get the same problem.

My monitor is a LG W2753VC and im using 1080p

Using a DVI-DVI cable its just impossible to work. Noise is everywhere and the monitor sometimes blacks out for few seconds before it restores the image.

After going out to buy a HDMI-HDMI cable that plugs directly to the mac (no adaptor) it reduced quite alot but still i get flickering and noise glitches quite often. It still blacks out my screen too.

note: while writing this post my monitor blacked out twice and i just lost count on the glitches/flickering. Appl get to work and gets us a fix