Hello,

instead of clogging up the PSU modding sticky I decided to post this in its own thread (although this will be linked to the sticky). I did a fan swap for the PSU that came with the NSK6500. It's a 430W version of the PSU shown in the SPCR review of the Antec NSK2400.

EDIT: I kept talking about the 380W version, but it is 430W.

First some pics of the internals:







Here's a pic of the original fan (high speed sleeve bearing by ADDA) and the 2-pin fan connector.



I replaced the connector with a "regular" 3-pin by soldering it in place of the original connector. The picture also shows the fan controller thermistor on the heatsink.



My replacement is my usual NMB-MAT 80M1BX (Panaflo) from Dorothy Bradbury, a medium speed fan with the tacho. I used two separate connectors on the fan, one for the internal fan controller header and another connector for the tacho. The tacho signal / connector is taken outside the PSU and connected to a motherboard for monitoring the RPM.



The end result. I had to remove the fan mounts I intended to use, because the PSU PCB is literally touching the fan frame. It was simply impossible to mount it inside the PSU with fan mounts.



After running it in my new system I'm a bit concerned about the fan voltage. Similar to the SPCR review I cannot the fan voltage to rise above 5V even after extended periods of stress testing. (EDIT: meaning my new system draws below 200W and the fan voltage stays below 5V for those loads). The air coming out of the PSU remains well below <40C, but obviously with a slower fan the airflow is very small.

I have ducted the PSU to the front bezel (see the temporary cardboard duct and the 5,25" cover plate I modified) for cool intake air, but I still may end up using a fanmate to set the fan at ~6V.

The intake area in the cover plate is smallish, but the NSK6500 has a raised front bezel that allows air intake through the sides of the front bezel.







Spank you very much for reading,
Aleksi

Perfect idea with using the floppy adapter blank to let air into the duct.

Hi qviri,

you're right, that would have been a perfect idea. Just realised that...

My original plan was to use a proper drill and movable drill bench at work to carve the front plate so, that I would have ended up with just a thin frame. However I realised that the bench would have probably influenced too much pressure to the frame, causing it to break. So I ended up drilling out just the small area that is now covered with perforated sheet.

You can actually see the 5,25" plate with the floppy adapter still in place in the last picture.

-Aleksi

Did I miss something? No reason is given for the fan swap.
Edit: Ah, lower noise fan. Read it in an entirely different thread.

Alexi, do you own a Dremel or equivalent? The heavy part of the fan frame futhest from the back of the PSU (the fan mounts to the back) is totally irrelevant if not used for mounting, you know. The only reason for its existance is for mounting purposes, for an intake fan for instance.

Since the fan is being used for exhaust, you can dremel off that part of the fan casing in complete safety, without affecting the fan's cooling or noise or reliability in any way. And that would make room for the rubber fan mounts, which would affect the noise (in a good way).

To simplify the job, only dremel off the part of the fan casing that actually interferes with the board. Nothing to it, easy as pie. I recently removed part of a Silent Wheel's fan casing, for just such an interference problem. Worked great. I even posted pics here at SPCR.

From the text and photos I know that the stock fan is a high speed model and probably not very quiet. The panaflo hydro wave bearing is much longer lasting than the adda sleeve bearing, and it's always nice to have a tach.

Felger...

Yes I forgot that, good point. Now it seems just like all the other nonsense without meaning posted on SPCR time to time.

I swapped the the original fan out of there, because...

- The noise signature for the fan was not very pleasant
- It was a high speed fan that created a bit too much noise even at 5V (in combination with the above statement)
- It was a sleeve bearing, which I do not want to have as a PSU exhaust

one thing also... the original ADDA didn't seem to have very good pressure capability. I'm sucking air through the PSU internals, PSU casing and then the front panel so using a Panaflo does help when making it quiet and cool.

yes, using fan mounts never hurts. But dremeling the fan frame would not help. If I use this "|" to symbolize the fan and this "____" to symbolize the PSU PCB, it would be like this "_____|"

The entire bottom part of the fan is at the PCB level, so I would actually need few millimeters off the entire fan. I did consider about using a 80x20mm fan in there.

frankgehry...

well you said it pretty much.

Thanks for looking.

Great work Aleksi! Did you consider mounting the fan outside the PSU?
Then you could use soft fan mounts.

Hi Peterson,

thanks for the nice reply!

If you look at the picture with the new fan mounted, you can see the parts where you put the fan screws is lower than the rest of the PSU casing.

So if I had used stick type fan mounts the frame of fan would still touch the metal casing.

I thought about using EAR grommets, but that I would have had to enlarge the fan screw holes slightly. I need a new set of drills before I could do that, so didn't bother with that choice other.

Thanks,
Aleksi

Yes i noticed that. I have used pieces of cut foam to mount a rear fan on one of my computers. I just pressed it through the holes of the fan and then in the holes of the case. Put some tape around it so the air won't sneek through the wrong way. No picture though.

Interesting, my NSK6500 came with the SU-430 PSU.

So did mine...

I'll change the thread title.

So the first post should say "a 430W version of the same PSU that was reviewed with the NSK2400"

just to make sure I understand, the source of current for the fan is still the PSU, and its controller is sufficient for keeping voltages low thanks to the duct?

Hi Cloneman,

Yes, the fan is controlled by the PSU's own fan controller.

And yes normally you use a duct to provide cool air to the PSU and to prevent the PSU fan from ramping under load.

But, in this case the PSU keeps the fan voltage below or at 5V even without the duct even at full load, which gives me exhaust temps just below 40C. Also if you look at the duct you can see it's not really "airtight", so not sure how much it actually helps at the moment.

I personally would prefer just a bit more airflow at full load, so I'm going for a proper duct and putting the fan to a fixed voltage or a fanmate. Probably aorund ~6V. Will need to test around with different voltages to see the PSU exhaust temps at full load.

Thanks for reading!

I was thinking of using a 1800RPM Noctua NF-R8 connected inside the PSU, I have a SU380 .. I think it would work even in this heatwave ...

Is the 2pin plastic fan connector socket inside the PSU detachable? Because if it is, no need to mod, you could just plug a 3pin fan after ypu detach that 2pin socket and leave the pins exposed.

yes, you can probably use a flat screwdriver to pop of the plastic 2-pin socket so that the pins would remain intact. I decided to replace the entire connector because I had proper 3-pin male connectors lying around.

(And I wouldn't use a Noctua in PSU, especially in a bit crowded PSU like the one above that requires some pressure capability from a fan)

i have an su380 and have just done a fan swap.

BE VERY CAREFUL- as i was dislodging the 2-pin from the fan controller pcb, i accidentally loosened it from the main pcb and now its not working
easily soldered back on but a pain in the ass.

right now i have it controlled with a fanmate and its spinning @835rpm.
this way i can monitor the rpm, i also don't have any soldering gear......

replacement fan was a 1900rpm coolermaster.
its doing okay but i think its not so good at pulling the air through all the components.

- i've got an antec nsk3400 so i also removed one of the molex leads and the pci-express lead, i figured i'd never use them. i may even remove another molex lead if i ever get a sata dvd drive.

I was very careful I extracted the connector and put the Noctua NF-R8 inside, the exhaust air is hot but not excessively hot ... it was hot before the fanswap anyawy ...

The noise is gone, at the 800-900RPM that the internal fan controller ramps it up, it should be. No thermal problems in 30*C ambient, with a overclocked c2d and a 7900gs.

Go Antec (Seasonic)