Fan at max speed, PSU thermal sensor shows no readout
Since yesterday, my iMac (A1419 EMC 2806) fan has been maxing out from power up, regardless of safe mode, recovery mode, or booting into Windows (via Boot Camp).
Diagnostics return error PFM006
Assuming a thermal sensor defect, I installed iStats to check the thermal sensors. Readout below in the screenshot - all temperatures are within normal ranges, the fan is at maximum and also won't slow down if I try to do that manually, and the only temperature that's missing is the one from the power supply unit (AC/DC T2 secondary heat sink).
So my question is: Is there even such a sensor in that model, do I expect a readout here? Have I thus found the probable cause and should be looking into the connection or the sensor itself, or the power supply unit (I heard the sensor is integrated into it, when it exists)? No other hardware or software changes made recently.
Have to revise myself, I tried it without the display connected and the fan went full speed, but I forgot that the LCD features thermal sensors for itself that weren't connected then!
When I connected the display, the fan seemed off, but now I broke the connector cable and I have to wait for a new one :-( so maybe it's solved, I'll update...
After exchanging my damaged display cable and bending the connector back to get it to work, I can now confirm that after exchanging the power supply unit as a whole, everything works perfectly! No fan powering up anymore, and iStats shows a normal temperature value for the AC/DC T2 sec. heatsink (I'll post a screenshot later, just have to restore the OS first as after doing a quick check, before reassembling everything I used the opportunity to upgrade to an SSD and a better CPU)! So yes, it was the power supply, and you have to exchange it as a whole indeed! Sadly,I couldn't locate the sensor on the power supply, it'd be a shame if you couldn't solder on just a new one!
Questa è una buona domanda?