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iMac 24" with washed out colours - Help!

post #1 of 16
Thread Starter 
My iMac 24" Aluminium (June 2008) running 10.5.8 has behaved impeccably for almost two years. I use it for graphics and photographic work, so colour fidelity is very important.

A few days ago, in the morning, the machine was still "perfect". By lunchtime I realised something was not right. The Photoshop file I had been working on looked different. I could not see details in highlights, transparency in layers that was clearly there in the morning had suddenly vanished. Looking closer at the whole screen I realised the whole environment was washed out - not just in Photoshop files.

I tried:
Calibrating the monitor - no difference.
ColorSync Utility: Verify/repair - reported loads of errors but fixed nothing.
Took the mac to authorised Apple repair shop in Hove (UK). Spent time with the engineers trying to sort it out. They had not experienced this before.
We connected 2nd monitor. Strangest thing: The same moment the 2nd monitor was connected, the native screen instantly looked fine. Both monitors fine.
Disconnecting 2nd monitor, and the native screen went bad again.
Booted up the iMac with their external drive and system (sorry, not sure which system but probably the same 10.5.8). The screen looked fine, even without a 2nd monitor. Rebooting with native OS and the screen went bad again.
Conclusion: Corrupt file in the system somewhere. Advice: Reinstall system (archive/install).

I did this today. Screen is the same bad screen, so reinstalling 10.5.2 and upgrading to 10.5.8 did NOT solve the problem. Erase and install is my VERY LAST resort. I really don't want to start from scratch with new system, new installation of applications, updates, settings etc.
I would rather buy a small 2nd monitor, watch the screen look good again, having another screen to use and PRETEND I DON'T HAVE A PROBLEM!

Questions:
Has anyone any idea what this can be?
Is it possible that upgrading to Snow-Leopard can solve the problem (but that is also just an upgrade and not a clean start?)

I enclose a screen-shot section of the desktop showing that the finder window has no contrast in highlights (blue and white horizontal stripes are only visible when another window's drop shadow multiplies with the background. Also, the green stripe has banding in the lighter part instead of being smooth). At least, that is what it looks like here!

Thanks for any help!

post #2 of 16
Quote:
Originally Posted by Johan Siebke View Post

I enclose a screen-shot

The screenshot looks ok here, you'd have to take a photo of the screen but the description is enough.

I would try moving the file /Library/Preferences/com.apple.windowserver.plist to trash, don't delete just yet. Then reboot.
post #3 of 16
Thread Starter 
Quote:
Originally Posted by Marvin View Post

The screenshot looks ok here, you'd have to take a photo of the screen but the description is enough.

I would try moving the file /Library/Preferences/com.apple.windowserver.plist to trash, don't delete just yet. Then reboot.

Thanks for the tip, Marvin. Just tried it (the file is still in trash, not emptied) but it didn't solve the problem. Should I put the file back in the library?
post #4 of 16
System Prefs -> Displays -> Color -> Display Profile -> change this to something else and report back.
post #5 of 16
Thread Starter 
Quote:
Originally Posted by 1337_5L4Xx0R View Post

System Prefs -> Displays -> Color -> Display Profile -> change this to something else and report back.

It has been tried several times (also together with Apple repair people) with no fundamental change. Tried it again now but same old story. I did a calibration as well when I discovered the fault but the new profile didn't solve anything.

Thanks for suggesting - keep them coming!
post #6 of 16
It´s likely a hardware issue.

You can install OS X from the install DVD´s on a external drive and hold option to boot from it as a last verification method.

After you have done that, you can clone your whole boot drive to a blank external drive using Carbon Copy Cloner.

1: Disk Utility Erase with Zero a new blank drive equal to or larger than your internal (only needed once per drive to map off bad sectors)

2: CCC the boot to the external (Filevault must be off, Bootcamp needs another step)

3: Disk Utility Repair Permissions on both afterwards.

4: Hold Option boot to check the clone out that all works well.


You can chose to Zero the internal before bringing it in, they will install a new OS to see what the issue is. When you get it back (or another machine) you can hold option and boot form your clone and reverse clone, a piece of cake.


With bootcamp method link

http://theappleblog.com/2010/01/12/h...-to-a-new-mac/
post #7 of 16
Thread Starter 
Thanks SpotOn. You touch onto a few things that sounds scary to a lay-person as I am.

Just to confirm: The Apple engineer booted my iMac from their own drive with their OS (10.5.8??) and the screen looked fine. As soon as it was booted from my own internal OS it was bad again.

Also, with the mac booted from my own OS (normal startup) and screen being faulty, as soon as a 2nd monitor was attached both screens went fine. As soon as 2nd monitor was detached, screen went bad again. Their conclusion was therefore an OS failure somewhere. Graphics and converter cards were obviously able to drive the both monitors correctly at some stage.

In terms of corrupt Prefs files, I had a look at what had changed. I found two files that were updated about the same time as the fault occurred (java and Safari). I moved them to trash and rebooted but it was a wild goose chase.

Any good trying DiskWarrior or similar? Haven't got any of those utilities but could buy one.
post #8 of 16
If you make a new user account and log into it, is the display still bad?
post #9 of 16
Quote:
Any good trying DiskWarrior or similar? Haven't got any of those utilities but could buy one.

Not really, you already did a Archive and Install, so you should have a whole new OS.

My next guess is EFI. Which resides on it´s own partition on the drive and likely not included in a Archive & Install OS replacement.


CCC your boot drive to a external like I outlined above and option boot from the clone, use Disk Utility to Ease w/Zero the internal boot drive, this will catch the bad sectors and should wipe the EFI partition, then reverse clone and boot from the internal, see if that catches it.

If not, then you´ll have to C boot from the install disk, select Disk Utility Erase the internal and install OS X fresh and apps from fresh sources too. Option boot from the clone to transfer files and check out your old configuration.

Install your apps slowly, see if something you have installed, especially ones needing a Admin password, start causing your monitor to freak out again.


Make notes of everything you doing, if all this fails, your sure to have a hardware issue.
post #10 of 16
Thread Starter 
Quote:
Originally Posted by Marvin View Post

If you make a new user account and log into it, is the display still bad?

Thanks again. I just tried that - AND IT WORKED! Logging in as a different user (new account) and a perfect screen pops up.

That was the simple part. What next? Is it likely to be a pref file in my user Library, or something else?
Is it a needle in the haystack job from now on?
post #11 of 16
Quote:
Originally Posted by Johan Siebke View Post

Thanks again. I just tried that - AND IT WORKED! Logging in as a different user (new account) and a perfect screen pops up.

That was the simple part. What next? Is it likely to be a pref file in my user Library, or something else?
Is it a needle in the haystack job from now on?


Download Onyx

http://www.apple.com/downloads/macos...ties/onyx.html


Under Verify, click Preferences and show corrupted .Plist files


It´s good to run all of Onyx´s features every once in awhile, sets your machine back to the first install state on the system level. Cleans up a lot of junk and unknown errors. Will slow your machine a tiny bit until everything is rebuilt, especially Spotlight indexing.

Sorry I didn´t think of this sooner. I´m running a lot of virtual machines OS´s lately and if it screws up I simply load a earlier saved version of the whole OS in seconds, it´s spoiling me.
post #12 of 16
Quote:
Originally Posted by Johan Siebke View Post

TThat was the simple part. What next? Is it likely to be a pref file in my user Library, or something else?
Is it a needle in the haystack job from now on?

Yeah it's kind of needle/haystack time but there aren't many places that settings go. If you rename the Library/preferences folder in your home folder to preferences2 and then log out and log in, that will let you know if the problem is in that folder. Then you can do a corruption check mentioned above. It might be the com.apple.ColorSyncCalibrator.plist, seems like the most obvious one. If you put it in trash, log out and in, you would be able to tell.
post #13 of 16
I just tried this on my own machine, and all of your symptoms appeared.

Your contrast is boosted. Hold Ctrl-Opt-Cmd and press Comma a few times.
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post #14 of 16
Thread Starter 
Quote:
Originally Posted by Karelia View Post

I just tried this on my own machine, and all of your symptoms appeared.

Your contrast is boosted. Hold Ctrl-Opt-Cmd and press Comma a few times.

GENIUS!! It was that simple!! I must have accidentally held Ctrl-Opt-Cmd and pressed full stop a few times during work. Now reversing it by pressing comma instead. This is a command I did not know existed.

And just to be clear, this has nothing to do with brightness slider in System Preferences -> Brightness. This stays the same regardless. I don't know if there is a manual contrast slider anywhere, there isn't one in System Prefs > Display.

Thanks for your help guys - much appreciated! I'll buy you a beer if you're ever around here!

PS: Is there a comprehensive list of Apple OS key commands and short-cuts in the public domain somewhere? In other words, could I have solved this by just looking on such a list?
post #15 of 16
http://support.apple.com/kb/ht1343


Glad your problem got solved, funny the Apple store techs didn´t catch this, a high/low contrast screen is rather obvious.
post #16 of 16
Thread Starter 
Just to sign this one off I post the reply from the Apple repair man when I told him:

"Hadn't thought of that one...

Just so you know that is accessed in

System Preferences/Universal Access/Display

Should be set on normal....

Should have dawned on me... but your display was not toooo bad... is
commonly done by students to each others machines... as at the extreme
it looks as if you have a serious display problem... Check it out!!!

Didn't realise that there was a keyboard shortcut for it though...

Anyway, glad it is resolved...

And thanks for letting us know.... not sure why connecting an external
display overrides those settings... but interesting!!!!"
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