I had this issue recently and after analyzing the schematics for the iMac 2011, I found that two tiny inductors (ferrite beads) in the ambient temperature sensors' path have been knocked off somehow and that caused the ambient temperature sensor not to work and in turn the system sped the fans up and slowed the cpu down. This issue has nothing to do with the hard drive it just happens to many people while they're disassembling the machine, the two inductors are right near the ambient temperature sensor connector (L5500 & L5501) and I guess can be knocked off easily. It can be fixed with some soldering skills and there's no need to remove the logic board for the repair. I don't think there is a need to replace the parts they're just there to reduce some radio frequency. If you do want to replace them they're both a 220 ohm ferrite bead SMT size 0402 (1005 metric).
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After my discovery I found some guys on a [http://advancedreworks.com/forum/showthread.php/imac-27-quot-2011-820-2828-a-1468.html|Repair website] mentioning a few times that they've dealt with this issue on the iMac 2011.
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After my discovery I found some guys on a [http://advancedreworks.com/forum/showthread.php/imac-27-quot-2011-820-2828-a-1468.html|repair website] mentioning a few times that they've dealt with this issue on the iMac 2011.
That fix that was mentioned about the LCD temp sensor being inserted incorrectly was only for the iMac 2010 based on what I found in the schematic for that machine.
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This is a picture of my repair I just added two traces of solder to replace the missing ferrite beads.
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This is a picture of my repair, I just added two traces of solder to replace the missing ferrite beads.
I had this issue recently and after analyzing the schematics for the iMac 2011, I found that two tiny inductors (ferrite beads) in the ambient temperature sensors' path have been knocked off somehow and that caused the ambient temperature sensor not to work and in turn the system sped the fans up and slowed the cpu down. This issue has nothing to do with the hard drive it just happens to many people while they're disassembling the machine, the two inductors are right near the ambient temperature sensor connector (L5500 & L5501) and I guess can be knocked off easily. It can be fixed with some soldering skills and there's no need to remove the logic board for the repair. I don't think there is a need to replace the parts they're just there to reduce some radio frequency. If you do want to replace them they're both a 220 ohm ferrite bead SMT size 0402 (1005 metric).
After my discovery I found some guys on a [http://advancedreworks.com/forum/showthread.php/imac-27-quot-2011-820-2828-a-1468.html|Repair website] mentioning a few times that they've dealt with this issue on the iMac 2011.
That fix that was mentioned about the LCD temp sensor being inserted incorrectly was only for the iMac 2010 based on what I found in the schematic for that machine.
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This is a picture of my repair I just added two traces of solder to replace the missing ferrite beads.
I had this issue recently and after analyzing the schematics for the iMac 2011, I found that two tiny inductors (ferrite beads) in the ambient temperature sensors' path have been knocked off somehow and that caused the ambient temperature sensor not to work and in turn the system sped the fans up and slowed the cpu down. This issue has nothing to do with the hard drive it just happens to many people while they're disassembling the machine, the two inductors are right near the ambient temperature sensor connector (L5500 & L5501) and I guess can be knocked off easily. It can be fixed with some soldering skills and there's no need to remove the logic board for the repair. I don't think there is a need to replace the parts they're just there to reduce some radio frequency. If you do want to replace them they're both a 220 ohm ferrite bead SMT size 0402 (1005 metric).
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After my discovery I found some guys on a repair website mentioning a few times that they dealt with this issue on the iMac 2011.
+
After my discovery I found some guys on a [http://advancedreworks.com/forum/showthread.php/imac-27-quot-2011-820-2828-a-1468.html|Repair website] mentioning a few times that they've dealt with this issue on the iMac 2011.
That fix that was mentioned about the LCD temp sensor being inserted incorrectly was only for the iMac 2010 based on what I found in the schematic for that machine.
I had this issue recently and after analyzing the schematics for the iMac 2011, I found that two tiny inductors (ferrite beads) in the ambient temperature sensors' path have been knocked off somehow and that caused the ambient temperature sensor not to work and in turn the system sped the fans up and slowed the cpu down. This issue has nothing to do with the hard drive it just happens to many people while they're disassembling the machine, the two inductors are right near the ambient temperature sensor connector (L5500 & L5501) and I guess can be knocked off easily. It can be fixed with some soldering skills and there's no need to remove the logic board for the repair. I don't think there is a need to replace the parts they're just there to reduce some radio frequency. If you do want to replace them they're both a 220 ohm ferrite bead SMT size 0402 (1005 metric).
After my discovery I found some guys on a repair website mentioning a few times that they dealt with this issue on the iMac 2011.
That fix that was mentioned about the LCD temp sensor being inserted incorrectly was only for the iMac 2010 based on what I found in the schematic for that machine.