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Hello!
My iMac turns on normally, and on a screen I see some strange repeating stairlike pattern of almost black blocks of pixels. I type my password and press enter. After that the pc tries to complete the log in, it fails and reboots itself.
Please help)
This is the pattern
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Ouch! The herringbone pattern you are seeing is a GPU board failure. To repair it you'll need to replace the part ATI Radeon HD 2600 Pro, 256 MB - Apple P/N 661-4426. It's a lot of work given the age of the system you might want to consider getting a newer system as this system can only support OS-X 10.11.x El Capitan and no higher and many apps today likewise won't support it.
Here's a similar model's IFIXIT guide to replace the GPU board: iMac Intel 24" EMC 2111 GPU Assembly Replacement
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3 Comments
I have same problem. When I boot into safe mode it seems to be not having any issues. I did my best to keep it running long enough and it didn't happen. When I boot normally it keeps running into this problem frequently. Sometimes during login and sometimes after login. I reinstalled the OS and no help. Pressing the D key (via wired key board) to force hardware diagnostics never worked. I will keep trying. Hoping to get few more years of life out of it as I recently upgraded HD. My iMac is Early 2008 3.06 GHz Intel 24" EMC2211. Is there a guide to replace GPU assmebly for this model. ?
by rajsayshai
rajsayshaw - Use the guide I noted below.
by Dan
Thank you Dan. I will attempt. With the help of iFixIt guides, I upgraded the HDD in my iMac EMC2211 and I recollect the internals looking different that the images in the guide you noted below. I will give it a try. Thank you for your prompt response.
by rajsayshai