Question Dell Inspiron 3847 Motherboard and Case Fan

[jon0111]

I'm having issues with the case fan not running. It's nothing fancy--a single exhaust fan for the case that's connected to the motherboard. Thinking that it was a failing fan, I replaced the stock one with a Noctua. The four pin fan is connected to my motherboard's three pin connector. The fan works great during POST and when I access the BIOS, but stops once Windows 10 loads.

I have checked all connections and I have reset the BIOS to default settings--there is no choice in the BIOS for fan power management.

My last thought is that something happened during a BIOS upgrade. (Not sure the last time this happened.) I should be able to flash the BIOS/CMOS to correct an issue, right?

Any other ideas why the fan would work during POST, but then shut down? I was under the impression that the fan would spin at 100% once the computer was powered up.

 

[Quarkzquarkz]

On older motherboards there used to be a time where there was no way to control CPU fan speed. However there were some that could and not not control peripheral fans for anything else. Have you examined your motherboard for maybe an extra 4 pin connection? Back then fans will behave in whatever motherboard spec it was calibrated with. If last resort, you can try fan controllers which are fairly cheap these days and they can control all your fans in any speed you want. It could be that your BIOS update might have changed it or disabled it, Good luck!

 

[jon0111]

I'm not familiar with fan controllers. Is this a hardware or software solution? Would this be an easy fix for a case/motherboard that is this old?

Thanks for your help!

 

[jon0111]

I'll look into fan control software, but I'm pretty sure that the board is too old for this.
Interestingly, the manual shows a FANSYS2 connection for the chassis fan, but makes no mention of the FANSYS1 connector on the board (this is NOT the CPU fan connector) that remains unused. I wonder what it's there for if Dell did not use it. Maybe I'll give that at try.

 

[jon0111]

No luck. Resetting CMOS did not work. The fan turns on at startup and will run if I'm in the BIOS, but stops as soon as the OS starts up. It must have something to do with Dell's OEM hardware not matching up with standard fans. I'll find a Dell OEM fan or upgrade to a new system.