Chosen Solution
Hi everyone, I performed routine maintenance on iMac mod. A1311 replacing the thermal paste on the CPU and GPU only once the whole is mounted, the Mac emits the classic “beep” as if it did not detect any installed RAM. The RAM I checked is working, the only thing I notice if it can be relevant, that the HDD is not Apple’s owner. Another thing, the fans start at full speed. Is it possible that we caused the damage by replacing the thermal paste? Thank you all for the possible answers. Regards
Sounds like you upgraded the HDD at some point, did you follow this guide? iMac Intel 21.5" EMC 2308 Hard Drive Replacement If you jump down to Step 10 your system leverages the HDD’s internal thermal sensor to help monitor the systems internal temps. The systems SMC uses a bunch of inputs to control the systems cooling if one of the sensors fails to communicate to it, it will ramp up the systems cooling fans to protect the system from over-heating. When you replace the drive you do need to reconnect the sensor and depending on the drive you may need a different sensor as Apple has used different suppliers for its drives. You may also need a different solution now as most HDD’s no longer offer the needed interface for the sensor and in the case of SSD drives they don’t offer the needed sensor. If you jump to the SSD section Step 17 you can see the needed sensor OWC In-line Digital Thermal Sensor for iMac Late 2009 - Mid 2010 Hard Drive Upgrade
Did you over do the paste?
You don’t want the paste to ooze past the metal lid (in the case of the iMac chips)
