Changed fan in PSU.

adbee

adbee

adbee

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13 Dec 2010
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Hi,

I have just changed the fan in my EVGA 750w PSU as it was really loud.

I have put a Noctua 120mm fan in there, just soldering the neutral and 12v wires.

When I turn the system on the fan powers up perfectly then switches off or stutters for a bit. I put a game on to check that the fan came on if the psu got hot and it did. It seem that the Noctua fan needs more power to get it spinning than the stock fan.


So when the power supply gets hot or is using more power the Noctua fan spins, but it switches off in normal use. The old fan ran all of the time, is this going to be a problem?
 
I did the same to my Thermaltake toughpower 650. I put a Noctua NF P14s Redux 1500 in there. I had to take the 4 pin plug off and convert to 2 pin. Fan only comes on occasionally but has been fine now for about 2-3 months. Silent and pushes more air but takes more heat and voltage to kick in.
 
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Without airflow you may find hot spots in the PSU are not cooled. A semi fsnless psu will be heatsunk to allow for these idle times,yours won't be. That said only time will tell. If your PSU fails in 6 months due to capacitor leakage or switching transistor failure then you'll know why.

I'd recommend against the use of pwm fans in a PSU as they sometimes fail to spin at lower voltages. That a 3 Pinner would happily spin at.
 
I took the advice from OC staff as to what I should fit so if it's wrong I blame them LOL. I wasn't sure what start up voltage it would need so I asked them to recommend the fan for it. Originally it had a Thermaltake badged TT-1425B Yate Loon D14BM-12(L-SSS) in it that was rattling. This was 0.70A 140mm but I couldn't find any info on the start up voltage and it was a 2 pin connector.

The PC it's in is under no load at all and there is absolutely zero heat in the PSU. When I do put it under a little bit of pressure it heats up but not too much and the fan comes in but usually only stays on for about a minute or so and then it is cool again. It also stays on for a few minutes after the system is shut down, that is if the fan is running already when you shut it down. Taking your advice, I may get another 3 pin fan for it just to be on the safe side.
 
Tealc said:
Without airflow you may find hot spots in the PSU are not cooled. A semi fsnless psu will be heatsunk to allow for these idle times,yours won't be. That said only time will tell. If your PSU fails in 6 months due to capacitor leakage or switching transistor failure then you'll know why.

I'd recommend against the use of pwm fans in a PSU as they sometimes fail to spin at lower voltages. That a 3 Pinner would happily spin at.
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Well that is annoying, I might just buy a new PSU in that case, cant face replacing the fan again.

Any recommendations for something quiet and can power sli 670's?
 
It's a decent PSU so I'd just run with it if you don't fancy the rework. If it does fail it isn't likely to take anything with it.

And yes as above you could do that but also you could have the fan wired up to your CPU PWM if you are half decent with wiring.
 
Tealc said:
It's a decent PSU so I'd just run with it if you don't fancy the rework. If it does fail it isn't likely to take anything with it.

And yes as above you could do that but also you could have the fan wired up to your CPU PWM if you are half decent with wiring.
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That was my main concern, damaging other components if something happened to the psu.

Thanks for the help guys anyway, think I will roll with it and see how I get on.
 
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