27" iMac repair by baking the GPU in the oven!
One day in February 2017, my iMac 27" 2011 showed only pink vertical lines and half a green apple.
After some research I figured out that the GPU was defective. I found help on the internet with the advice to bake the GPU board in the oven to resolder the pins of the GPU processor. That made sense because the computer becomes very hot, and the GPU board is installed vertically behind the screen. Apple under Steve Jobs was always very much concerned by the design of the products, and they should not make much noise, so cooling was perhaps insufficient. So, after years of thermal cycling perhaps one single connection became defective.
Anyway I opened the computer, not the first time as I had already installed and SSD earlier. But this time I damaged a connector that is very difficult to loosen behind the very heavy 27” display. So before fixing the GPU the challenge was to find and replace the connector. I found it on eBay from an angel in the UK who promptly posted it to Japan in a padded envelope with the required stamp with the portrait of Queen Elizabeth II. The unsoldering of the defective connector from the main board was a bit a challenge using de-soldering braid it went well. Then to re-solder the new connector which has a 1mm pitch required me to use a magnification mask which I got from a jeweler at work.
The baking went well at degrees C from 12 minutes and was much less spectacular than expected. Then reassembling the GPU board with the cooling unit using thermal paste.
After fitting the rest together, I was very anxious about the outcome, but the familiar boom sounded, and the Mac started up normally.
Finally I upgraded the OS to the last version and my Mac was perfectly working again.
In April 2019 the same problem happened, and I applied the same procedure. But in January 2020 it failed again, and I retired it. Apple picked it up for recycling free of charge. I then bought a MacMini which becomes much less hot and I can hook up external displays of my liking.
Read MoreAfter some research I figured out that the GPU was defective. I found help on the internet with the advice to bake the GPU board in the oven to resolder the pins of the GPU processor. That made sense because the computer becomes very hot, and the GPU board is installed vertically behind the screen. Apple under Steve Jobs was always very much concerned by the design of the products, and they should not make much noise, so cooling was perhaps insufficient. So, after years of thermal cycling perhaps one single connection became defective.
Anyway I opened the computer, not the first time as I had already installed and SSD earlier. But this time I damaged a connector that is very difficult to loosen behind the very heavy 27” display. So before fixing the GPU the challenge was to find and replace the connector. I found it on eBay from an angel in the UK who promptly posted it to Japan in a padded envelope with the required stamp with the portrait of Queen Elizabeth II. The unsoldering of the defective connector from the main board was a bit a challenge using de-soldering braid it went well. Then to re-solder the new connector which has a 1mm pitch required me to use a magnification mask which I got from a jeweler at work.
The baking went well at degrees C from 12 minutes and was much less spectacular than expected. Then reassembling the GPU board with the cooling unit using thermal paste.
After fitting the rest together, I was very anxious about the outcome, but the familiar boom sounded, and the Mac started up normally.
Finally I upgraded the OS to the last version and my Mac was perfectly working again.
In April 2019 the same problem happened, and I applied the same procedure. But in January 2020 it failed again, and I retired it. Apple picked it up for recycling free of charge. I then bought a MacMini which becomes much less hot and I can hook up external displays of my liking.
