iMac 21,5" Mid 2011 Sensor problem

[Mixpower]

Hi,

I have a strange problem with my 21,5" Mid 2011 iMac, I have replaced the 3.5" HDD with a different one and added the OWC Temperature sensor and also installed a 2.5" SSD on the 3rd Sata connector on the logic board and installed a K610M with the custom rom.

Everything seems to work fine but as soon as I open Safari and play a video or do something else something happens to the Airflow 1 sensor and a lot of sensor readings just disappear and the iMac starts taking off like a jet engine and stays like that until I do a shutdown and PRAM reset and everything is fine for a short while.

Could this be a defective sensor or sensor cable of some kind? I also checked this topic but I don't see those traces on my 21,5" logic board. https://forums.macrumors.com/thread...ilure-after-installing-another-drive.1710571/

I have recorded a video of what is happening, when the sensors disappear the CPU and ODD fan start to ramp up but the HDD fan stays normal. I have tried this with and without the Catalina loader with the same results, could this be a GPU problem?

Any help would be appreciated!

 

[cesarvog]

I may be wrong, but I think the OWC cable with sensor (which I have installed on my 21.5" iMac 12,1) is only intended to be installed on the original hard disk connector. I replaced the original 7200RPM HD with an SDD, which I connected to the OWC sensor cable, which was then connected to the original HD cable and glued the OWC sensor cable to the Samsung SSD. It works perfectly.

 

[Mixpower]

Thank you for your reply, but as far as I know the OWC sensor is for any HDD or SSD instead of the Original HDD with integrated sensor. I have the sensor cable attached to the original cable going to the logic board, the SSD is connected to the 3rd unused connector on the logic board.

 

[cesarvog]

Yes, of course any HDD or SSD. What I meant is that I think it has to go into the cable that was connecting the original Hard drive (1st SATA connector). Maybe I misread and though you added the OWC cable with sensor into the 3rd connector.