Replacing the fan in my PSU?

[downhiller80]

I don't have a massively powerful system I think - see my sig. I only have one data drive now, so only 2 hard disks.

The noisiest thing in my case at the moment is the power-suppy, so I'd like to put a quieter 120mm fan in it, especially since I'm sure I'm running nowhere near the 500W it claims to be capable of (though I expect the fan speed is variable so in theory running as slow as it can/should already).

I'm happy soldering a new fan on if need be, or will it likely just be plugged in?

Any advice generally, or specifically on which fan I should get?

cheers

edit: link http://www.zalman.co.kr/Eng/pr...oduct_Read.asp?idx=195

 

[covert24]

well on any psu that i have taken apart it was soldered in. But there is a possibility that it might have a plug. If it does you can just strip the wires from the plug and splice them onto the new fan wires and just insulate it with some electric tape. Get something like a low sped yate loon or the like.

 

[BassBomb]

Covert hit the money.

Also be aware you will void the warranty of your PSU by opening it up. If you can why not try oiling the bearing to see if it will cure the problem before dropping a fan in.

 

[covert24]

yea also make sure you completely drain all the power from it before hand. dont want to get electrocuted lol.

 

[Zepper]

Also check the measurements, the 120 fans they use in PSUs may be thinner than the normal 1" or 25mm. Jab-tech has some Yate Loon that are 20mm thick - IDK about the availability of others.

.bh.

 

[downhiller80]

Good call zepper, I'll see if I can find out without having to rip it apart.

How long should I let caps drain for after unplugging, is 8 hours (overnight) overkill?

 

[MarcVenice]

Lol I did do no such thing as 'draining', just don't touch anything with your bare hands ? I dropped in a antec tricool btw, in a coolermaster 650w extreme power. It wasn't soldered on, but plugged in instead. I had to cut of the headers from the old fan, and I soldered those onto the antec tricool, insulating tape like covert said, and I was done.

 

[Zepper]

I just put my cheap PSU tester on there and unplughed the PSU instead of turning off the power switch - and then I leave the tester connected w/ pwr switch on while working - I took my meter and didn't find any significant voltage once the LEDs in the tester went dark.

Most times I cut and splice the leads whether there is a plug or soldered as your fan will not likely come with the correct size of connector, but sometimes 3-pin female will work. All you need is some heat shrink tubing to protect the connection besides the soldering iron/solder. Try to match the fan specs as closely as possible to the original re. current (Amp) or power (Watt) so any thermal control in the PSU will work reasonably well with the new fan.

.bh.

 

[covert24]

yea you dont have to let it drain for anywhere over 5 minutes. if you are going to be soldering you might want to take the whole pcb out so you can have better access to it.

 

[downhiller80]

OK, well I got around to doing this today. Cut up an old fan adapter, chopped the old fan off, and coupled those together with lots of twisting and tape, so I now have a socket should I decide that I want to change the fan I'm running.

Nave put my Noctura 800rpm fan in, and naturally it's pretty quiet.

Of course what I'm worried about is things overheating - with a CPU/GPU etc you can monitor the temp from the PC, not so with a PSU. Can I gleam anything from looking at the motherboard voltages, i.e. if the PSU is overheating will they lose accuracy?

FWIW I also cut a big hole in the back of the PSU, to minimise restriction on airflow. Also means I can reach in and touch the heatpipe heatsink zalman has in their PSUs and it's not even remotely warm, so that's a good start.

Oh, and I'm pleased to confirm that this PSU does have a 25mm thick fan. Though if it hadn't I would just have mounted the Noctura on the underside of the housing instead of in the housing.

PC is now RIDICULOUSLY quiet :-D

 

[Zepper]

Noctua 800 rpm fan is Not the type that should be in there if it ever does get hot. Hardly puts out any air even at full speed. And the thermal fan control built into the PSU probably won't even let it crank fully. New fan should match specs of the old as closely as possible re. current (Amps or milliAmps) or power (Watts)

.bh.

 

[downhiller80]

To be fair the fan that was on there didn't seem to be moving a massive amount of air, just making a lot of noise... More than the Noctura maybe, but not a huge amount more. My Noctura 1200 appeared to move MORE air in fact. Which is odd - the old fan is rated at 0.33A, the 1200 at 0.12A and the 800 at 0.05A.

Does make me a little nervous I suppose that I'm running a fan 1/6th the power of the old one...

Do PSUs have any safety built into them? If it's overheating will it switch itself off, or will my first warning be when something fries and then it never works again? Worst case scenario is obviously a fire, but I gotta presume that they have sensors to prevent against that and turn it off when it gets too hot?

This is the fan I took out: http://mouser.com/search/Produ...0%2FOtPoFqQlgnYA%3D%3D

By my calcs that CFM equates to 137m3/h (my noctura 800 claims 59m3/h, my noc1200 is 81m3/h).

My reasoning behind putting in such an "underpowered" fan is that the PSU makes a few assumptions:

1) power worst case scenario: I'm using all the power it can deliver
2) ambient worst case scenario: I'm living in a hot climate with no air-con and it's 45°C
3) system worst case scenario: I have a rammed case with poor airflow

A PSU manufacturer would have to assume all of those things to be able to claim their product safe, I imagine?

In fact I'm using nowhere near the full power output, I live in the UK where my ambient is about 20° normally, and may peak out at 30 in the summer, and I have a very uncluttered case with good airflow. This MUCH quieter fan can achieve half the airflow of the old one, and I'd be a little surprised if that isn't more than I need?

 

[Zepper]

Yes, the PSU does have multiple safeties, but you don't want a safety cutting in while writing to a Hard Disk or such - disks get fragged that way. The reason your OEM fan wasn't putting out much air was because the PSU wasn't getting hot. The PSU has a thermal fan controller (simple, thermistor based) built into it that is matched to the power characteristics of the OEM fan - that's why any replacement should closely match it in power or current as the thermal control is tuned to that.

.bh.

 

[downhiller80]

I was about to have a go at you for not having suggested this earlier in the thread, but then re-read what you had said and saw you did, doh ;-)

 

[The Boston Dangler]

i have a silverstone ps, originally enlight. i replaced the loud adda fan with a noctua 1200. to my shock, the polarity was reversed on the board and original fan! watch out!

 

[imported_wired247]

just thought I would throw this in there.......

I would not use electrical tape inside a component that is known for getting warm. Use heat-shrink tubing, it is cheap and infinitely better, and will never make a mess or come loose.

 

[downhiller80]

Haha, cheers Boston, have checked and mine seems ok

Wired: fwiw they're actually outside of the PSU, running the original wire through the grommet along with the ATX power connector etc, then once it's outside of the PSU I have a socket bodged onto it, then I'm taking the cable for the noc. fan outside of the PSU too and plugging it in. Reason for doing it all outside? The noctura has a 15" cable that I didn't want to chop off in case I decide to switch fans, and I didn't want to coil all that up within the PSU.