If your iMac starts with a screen similar to this:
don’t worry! There is a solution. Apple admit that they had bad hardware in a certain line of 2011 models. Apple offered to replace the videocard for free. But that offer has expired. I was not even aware it existed.
Never mind, the Apple store says that replacing the videocard will be between 600 and 700 euro.
That’s an expensive solution, so here is a cheaper one:
Bake your video card in the oven
I found this YouTube video about opening the iMac and put the card in the oven.
Here are the ingredients for the recipe:
- Torx T10 (almost all screws are t10)
- Torx T9 (2 screws holding the video card to the cooling system)
- Cooling paste
- regular Phillips screwdriver
- 2 suction cups
- a bit of aluminum foil (to make 4 aluminum balls to stabilize the card in the oven on the plate)
- conventional oven (with bottom and top radiation and a plate)
I also used some alcohol, tissues and q-tips/ cotton bud to remove the old cooling paste
Start by removing the ram modules from the bottom of the iMac.
Follow the steps in the video to remove the glass with the suction cups and remove 4 screws on each side of the panel to tilt the panel and disconnect all 4 connectors. Remove the panel and disassemble the main board/ logic board. The required screws cannot be found in the video. But you can find then in this video:
The link starts the video at 4 minutes and 55 seconds. Which explains the screws you need to remove for the main board. afterwards you need to remove all connectors on the front. Tilt the board and remove the connectors on the back.
Follow that video to the end and then continue with the previous one to remove the cooling from the videocard.
clean the videocard and put it on 4 aluminum balls on a plate and put it in a pre-heated oven for 8 minutes on 200 degrees Celsius.
put new thermal/cooling paste on the chips and re-assemble everything. Do not forget the ram modules.
Here are some pictures from my baking experience: