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Mac Mini Won't Read Fan Speed After Repair

JDiggyDawg

macrumors member
Original poster
May 26, 2017
31
9
West Jordan, UT
Hi everyone,

I had a co-worker that attempted to swap out the hard drive on his family Mac Mini, but accidentally broke off the fan connector. He was going to just toss the machine, but I took it and was able to get it resoldered along with replacing the hard drive. Everything is running fine, but the fan speed is basically running at max most of the time. I tried downloading Mac Fan Control, but it's just giving me a 0 on the rpm's. The temp sensors are working just fine, but the machine just can't see or control how fast the fan is going.

Has anyone run into this or know what might be going on?

Not a terrible outcome from all of this. I guess the Mac will just run a lot cooler ALL the freakin' time if I can't get this fixed.
 

Slash-2CPU

macrumors 6502
Dec 14, 2016
400
259
One of the wires/pins are broken. One wire in that connector is the fan speed sensor.

When you say he broke the connector, which side is broken off? Motherboard side or fan side?
 
Comment

JDiggyDawg

macrumors member
Original poster
May 26, 2017
31
9
West Jordan, UT
One of the wires/pins are broken. One wire in that connector is the fan speed sensor.

When you say he broke the connector, which side is broken off? Motherboard side or fan side?

Motherboard side. It’s a fragile solder to the board so it popped right off when he tried to pull the fan out.
 
Comment

Slash-2CPU

macrumors 6502
Dec 14, 2016
400
259
Most likely, your solder job has caught not every pin.

Small possibility, the fan speed input circuit on the motherboard is damaged.

Either retry solder(best option) or add a separate variable voltage fan controller and power it off 12v from Mini or a separate wall brick to power fan. You can follow the trace and look "upstream" for an easier point to grab for soldering the sensor wire. If the solder pad is totally ripped off, I've had good success before by following the traces on the board for another solder joint on that trace and piggybacking it.
 
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