Model A1311 / Late 2009 / 3.06 or 3.33 GHz Core 2 Duo processor

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Internal display not working after gpu replacement

Hi all!

I have a late 2009 21.5" imac with an ati 4670 graphics card.

One day it won't boot anymore (white screen). If booting with the shift key helt down, the imac boots but without graphics acceleration.

So I replaced the graphics card. Now after turning it on, the display remains black. An external display (TV) works fine. So at the moment I can do everything on my TV, even graphics acceleration works.

But the main iMac display remains black. The backlight works. I triple checked if the fat display data cable sits tight and it seems ok.

So what can i do now?

Answered! View the answer I have this problem too

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1 Answer

Chosen Solution

Sounds like the vertical sync cable is damaged or not connected correctly.

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the vertival sync cable? you mean the display data cable?! as far as I read the display should work but vibrate with disconnected v-sync cable. or am I wrong?


It's needed! Did you forget to connect it? And it's correctly inserted.


I took it to a local apple reseller. It was the lcd panel...


That's a bummer :-{


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Tom will be eternally grateful.
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