Graphical artifacts - iMac 27 late 2009

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MauserMan Author

Level 1

4 points

Graphical artifacts - iMac 27 late 2009

Hi all!

I've recently been having some graphical issues with my iMac.

These are my specs:

OS X El Capitan (10.11 15A284)

iMac (27 tum, sent 2009)

2,8 GHz Intel Core i7

8 GB 1067 MHz DDR3

ATI Radeon HD 4850 512 MB

The artifacts seems to be appearing when i'm doing something like looking at photos, watching movies etc. The nature of the artifacts present themselves as follows:

1. Black windows

2. Black scrambled menus (mostly unreadable).

3. Filenames under documents are gone.

After this has happened, I usually can't boot normally anymore. When I boot the iMac, everything looks normal at the beginning, The apple logo appears as does the progress bar. But when the progress bar disappears, the screen goes grey and it just sits there, doing nothing. When this happens, five vertical pink lines are visible on the screen. Afterwards I can only boot via safe mode, and after doing so, everything looks just fine, Icons, menus, windows everything looks as expected.

The first time I had this issue was under Yosemite, about two months ago. I managed to recover from it then, but I'm not sure exactly how, since I tried a whole bunch of different things that i came up with, i.e. reinstalling yosemite, repairing permissions etc. The pink vertical lines were visible then as well.

Right now while I'm writing about this I'm in safe mode, and my desktop together with its icons and menus looks just fine. Screen updates are slower obviously.

As far i can remember, the first time it happened was when i was playing UT99 under Wine, the next time was when i was looking at photos in Photos, and yesterday it happened when i was playing a movie in vlc, only this time it happened under El Capitan.

I've googled my problem of course, and i did find a lot of similar issues, but i'm not sure what to do.

I guess my question boils down to this:

Is it a hardware issue or not, and in that case what hardware is likely causing my problems (the logic board or the graphic board)?

Thanks a lot for your help!!

iMac (27-inch Late 2009), OS X El Capitan (10.11)

Posted on Oct 10, 2015 7:15 AM

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Answer 1

rkaufmann87

Level 10

140,472 points

Oct 10, 2015 7:30 AM in response to MauserMan

You may have a failing GPU, have your run Apple's Hardware Test in extended mode 2-3 times back to back?

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Answer 2

MauserMan Author

Level 1

4 points

Oct 10, 2015 4:13 PM in response to rkaufmann87

rkaufmann87 wrote:

You may have a failing GPU, have your run Apple's Hardware Test in extended mode 2-3 times back to back?

Hi and thanks for your tip.

Thats definitive something I would do if only I could find my system disk that came with my machine. I'll look some more and hope for the best.

Another thing I thought of is connecting a second display, if that has the same artifacts, then it can't be the display anyway.

I did try booting while pressing option-D, but unfortunately nothing happened .

Thanks for your quick response.

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Answer 3

rkaufmann87

Level 10

140,472 points

Oct 10, 2015 7:17 PM in response to MauserMan

You can always contact Apple via AppleCare and for a nominal charge they will replace the DVDs, either that or you can have it professionally diagnosed at an AASP or do like you suggested and use an external display. If you don't know of any AASPs please click the AASP Locator to begin finding one.

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Answer 4

MauserMan Author

Level 1

4 points

Oct 21, 2015 8:14 AM in response to MauserMan

Just wanted to share with you that my graphic card is working again :-).

The solution?

I baked it in the oven for about ten minutes, due to a tip I found on Youtube. I know, it's seems crazy, but it actually worked.

Since I have two identical computers at home, I could switch the cards between them to be sure that it indeed was the card that caused the graphical error.

After that I followed the instructions on youtube, and baked my card, let it cool off and put it back in.

And it worked just fine, and still does.

I guess the logic behind this procedure is that there are bad solder points on the card, witch produced graphical artifacts on the screen.

Putting it in the oven for a certain amount of time, made the solder points melt, and created new healthy connections ones more.

It's only a couple of days ago since i did this, I know. But hopefully my repair lasts.

I'll keep my fingers crossed, this method saved me a lot of money :-).

Thanks all for your answers!!

Best regards from "The Swedish Chef".

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