Changing fan in Dell Optiplex 740

[percept]

Hi, looking to swap out the CPU/case fan in an Optiplex 740 with a quieter fan - anyone ever done this successfully ? I think the fan has a 5 pin connector which is a bit unusual. Thanks.

 

[ulysses35]

Whatsize fan is installed ? and are we talking about the CPU fan or the case fan ?

 

[percept]

Whatsize fan is installed ? and are we talking about the CPU fan or the case fan ?

It's a case fan, but there is a shroud leading to the cpu heatsink, so I guess it is a cpu fan as well. I think it is 120 mm based on some searching. It has a 5 pin connector to the motherboard which is proprietary. To me looks like a modification required or draw power from a spare 4 pin connector on the psu. But reading through various articles, would still need to use the motherboard connector to get pc to boot.....so perhaps not so easy?

 

[percept]

It's a case fan, but there is a shroud leading to the cpu heatsink, so I guess it is a cpu fan as well. I think it is 120 mm based on some searching. It has a 5 pin connector to the motherboard which is proprietary. To me looks like a modification required or draw power from a spare 4 pin connector on the psu. But reading through various articles, would still need to use the motherboard connector to get pc to boot.....so perhaps not so easy?

Ok, so as an interim solution I opened up the case, blew out all the dust that had accumulated, took off the heatsink and shroud, took out the fan and wiped clean, put back the fan, cleaned off the old cpu thermal paste, reseated the cpu, applied new thermal paste, and put back on the heatsink and fan. Turned on and everything worked - fan was noticably quieter but not as quiet as I would like. CPU temps at approx 40deg (I'm running an AMD Athlon 5400B @ 2.8Ghz). Ran Prime95 for a little while, temp increased to approx 60deg but fan did not get louder (previously while under load fan got significantly louder)

For reference the fan is a 92mm (not 120mm as I previously thought) DC Brushless model AFC0912DF, Dell P/N U7581, DC12V 1.43A; 4 wires from the fan leading to a 5pin connector on the motherboard labelled as "cpu fan". Connector has labels "MX" and "7A" for the first two wires (yellow and red wires respectively); other two wires in order are black and blue; 5th slot for wire is empty.

So while it has improved, particularly under load, would still like to quieten the fan more / replace with new quieter fan as I am using as essentially media centre in living room............any ideas ? How would I wire a standard 3pin fan to the Dell connector for example? Is there another way ? Thanks in advance for your help !