The famous fan full speed issue.

Hi,

There are other threads, but as they are old, so I decided to make a new one. Mac Mini 2010 mid and the famous fan full speed issue, with custom HDD disks and one HDD thermal sensor was missing. First I tried to remove one disk, hoping that if OS doesn't detect the disk, it also ignores the missing thermal sensor for the missing disk. Still fan runs at full speed. Then I tried to swap the two sensors and finally removed them at all kind apps, to reduce the full fan speed, but they didn't get the speed at all. Found that in logic board one component was missing ( Missing component on logic bord ) find same generation iMac schematic (didn't find Mac Mini schematic) based that soldered back replacement inductor and now apps (macs fan control (https://www.crystalidea.com/macs-fan-con...) or ssd fan control (http://exirion.net/ssdfanctrl/), showing the speed also temp but none of them does not reduce the speed. OS was 10.11, upgraded to 10.12.

For example using smcFanControl:

./smc -f shows:

Total fans in system: 1

Fan #0:

Actual speed : 5808

Minimum speed: 1800

Maximum speed: 5500

Safe speed : 0

Target speed : 5500

Mode : auto

When I add command to set fan speed to 3000 rpm:

./smc -k F0Mx -w 2ee0

./smc -f shows:

Total fans in system: 1

Fan #0:

Actual speed : 5804

Minimum speed: 1800

Maximum speed: 3000

Safe speed : 0

Target speed : 3000

Mode : auto

But actually the fan is still running at full speed all the time. Adding the 1/8W 2kΩ resistor between the two center wires on the 4 wire fan connector, does drop the fan to about half speed, but I'd still prefer that some software can automatically adjust the speed. Fan's sensor is working, as when I mechanically slow down the fan, the apps show also slower speed.

So what more can I do? I have seen threads, where software was able to adjust fan speed if one sensor is missng. I'm wondering, can software adjust fan speed at all, if all sensors are missing. If yes, then why isn't any software adjust the speed. Is the logic board fan control chip fried? How to test it?