Chosen Solution
Hiya, Second hand Mac Mini with a problem here. Fan is going full speed (I can hear it loud and clear), but reads 0 RPM. Software, like Macs Fan Control or smcFancontrol to lower the speed won’t work (can’t go lower then 0 RPM, so seems obvious). I’m missing 2 temperature sensors (the ones attached to the HD), which are coming in next week, however in my common sense that should not be the reason for tools to read the fan speed at 0 RPM. Am i missing a problem here somewhere ? Another loose connector or missing sensor or something ? SMC and PRAM reset will not work. Tried it. Sensor to Superdrive works fine. Any idea ? Cheers!
The issue is the tach inside the fan unit and how it communicates to SMC. This is were the connection of the fans connector could be backwards, or the logic board got damaged in the process of taking off the connector. There is a small resistor just behind the connector that some poeple pop off in the process of pulling the connection.
The sensors are what allow the temperature to be read. Without those the machine will most defiantly do as you have described. That is why you hear the noise from the fan but cant get a appropriate reading because the sensor is missing. Do you know if the hardware is all original?
