Replacing the PSU fan

nocturnal1974

nocturnal1974

nocturnal1974

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20 Dec 2010
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160
Hello,

I have an OCZ StealthXtream 400W PSU and I wish to replace the 140mm fan and I have narrowed it down to roughly the following choices as they all can shift air around 60 CFM:

1) Noctua NF-P14 FLX Vortex-Control 140mm
2) Be quiet! Silent Wings USC 140mm
3) Fractal Design 140mm Silent Series Cooling Fan (Only 39 CFM!)
4) Antec Truequiet 140mm (Only 32 CFM!)

The OCZ is an efficient wee PSU ranging from 82-85% efficiency and I got it for £30 new!

I am trying to fit the quietest fan available. I am not sure if the existing fan( yate Loon D14SM-12) is PWM controlled. I read somewhere Noctua fans do not like PWM control.

Note: There is only a 2-pin Black/Red power connector inside the PSU itself, I assume I convert the 3-pin connector to a 2-pin by removing the earth connection.
 
Check out my tutorial.

http://forums.overclockers.co.uk/showthread.php?t=18261286

As regards the choice of fan you do have to be sure that the fan can work well with horizontal mounting. Sleeve bearings won't cut it but fluid dynamic types will be fine and so will ball bearing. I went with the Magma 120mm because it has a high working temperature, decent MTBF and low voltage starting speed.

I'm actually surprised by the slowness of the fan in your PSU as the ones I've had from OCZ/FSP have all had 2500rpm fans in them. The fan will be DC controlled (not PWM) by the onboard fan controller inside the PSU by those two wires.

If there is a 2 pin connector you should just be able to fit the 3 pin connector to it without any issues, providing of course you follow polarity. If you choose to you can run the yellow tach wire back out of the PSU and onto a motherboard header for fan speed monitoring purposes. I did and it's always nice to see how the thermals of the PSU are affected by using a slower fan.

Note that in my tutorial I replaced a 2500rpm fan with a significantly slower fan (1000 rpm less) as the stock fan was clearly designed to be too fast. I used a thermometer to monitor the intake and exhaust temperatures shortly after fitting to ensure the PSU didn't get too hot.

As for the choice of your fan I'd be tempted to go for the Noctua, but it's 2/3 the cost of the PSU. You also have to be sure that the fan will start spinning at PSU idle voltage.
 
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Nope its only 14 months old but I don't care.

I have always taken everything apart since I was a kid and love modifying stuff for the better :cool:

Brilliant tutorial Tealc! I have all the kit e.g. heat-shrink etc. already;)

Whilst working on my hi-fi amps I always admired the huge heat-sinks allowing passive cooling. It would be good to have one side of the PC tower a huge heat-sink allowing fanless cooling:D

Anyway I'm still not sure which fan to buy although I am aware Noctua are tantamount to Rolls Royce and you would be lucky to get 6 pints of beer for the cost of this so I think I'll get it!

Many thanks:D
 
I suppose you could test the PSU fan wires using a multimeter to see what the voltage is when started up with no load/minimal load/idle load. A sort of worst case scenario if you like. Then shop for a fan that starts higher than that, has low noise and a decent bearing.

The Enermax Magma I used starts at 4.3-4.5v and a previous Scythe S-Flex I used in a PSU started even lower. Sadly no 140mm versions.

If the starting voltage is too low you can always power the fan via your motherboard or fan controller at a decent low noise speed as a compromise.
 
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I think this needs emphasising too:

Tealc said:
Doing this mod will invalidate your warranty. PSUs can be dangerous and some of the components, especially those on the Primary side, can carry lethal charges. Only undertake this mod if you are really sure you know what you are doing and understand the consequences. I accept no liability or responsibility if you void your warranty or fry yourself when touching or worse still licking a primary capacitor.
Click to expand...
 
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