[jvicinanza]

Hello all,

I have just purchased a new 23 Inch Apple Cinema display and attached it to my 17 Inch MBP.

When I am using it in non mirroring mode I see numerous green flashing groups of pixels horizontally accross the screen. It seems that when I go into Mirroring mode or close the lid on the MBP I do not get this issue.

Also when I connect my Powerbook G4 12 Inch into the Cinema display I don’t get the problem.

Ive read elsewhere on the Apple site customers experiencing similar problems to this happening with the 30 Inch display buy not the 23 inch. Furthermore the discussion on the 30 inch problem does not really provide any actual solution to the problem. Some folks think it is a display problem other a graphics card problem.

Ive took a photo of the screen which can be viewed at


http://www.futurafish.com/apple/apple.jpg

Any suggestions into the cause of this problem?

Many Thanks

Jason

[Cadaver]

Its most likely one of three things:

1) Bad display
2) Bad cable (but since the cable isn't removable, this essentially become same as a bad display)
3) Bad MacBook Pro (could be anywhere from graphics chip to DVI port connector)

Since you say a 12" PBG4 doesn't result in the same problem, I vote for #3. Time to use AppleCare.

[iDaver]

I had this problem with my 23 when it was hooked up to a G4 mini which barely had enough vram to drive the display. It was annoying but not too. When I replaced the mini with a G5, the problem was gone. So, I decided the problem was related to the low video memory issue.

Since you're not getting the pixel anomaly in mirror mode but get it when you're trying to span two displays, I'd guess it's a similar memory issue. As an experiment, try temporarily reducing the resolution on the MBP main display to see if it corrects the problem on the external. This guess of mine may be off base though. Aren't MBPs supposed to be able to drive 30" displays in spanning mode?

[jvicinanza]

The MBPs can easily drive (i believe) upto 8 30 Inch cinema displays so I guess that a 23" should be no problem.
Anyway ive kinda solve the problem. I took my MPB to my local Apple repair centre and they plugged it into a different 23"'er and it seems that the problem is with the graphics card. The cinema display is fine.

Its now in for repair.

Thanks for the suggestions however!

Jason
Paris, France

[jvicinanza]

You were correct sir. It was a bad MBP. Its in for repair.