Purposed of Auxiliary Fan

sglee
sglee used Ask the Experts™
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Fans on Computer
My computer made pretty loud noise, so I opened up the computer to find out what causes most noise.
As you see in the screenshot, there were 3 fans (the one in main PS, CPU and Auxiliary fan below main PS).
When I disconnected the connector from the MB for Auxiliary fan, the computer became significantly quieter.
That said, is it necessary to keep the Aux. fan when there are CPU Fan and Main PS?
There is one CPU, one HD, one DVDRW on this computer.

Thanks.
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Quid, Me Anxius Sum?  Illegitimi non carborundum.
Commented:
If it is the AUX fan making a noise then the bearing in it may be gone.

The purpose of the fan is up to you.  You can use it to add extra cooling to the motherboard (southbridge or northbridge chip, capacitors), to power a case fan (in or out), cool a hard drive or whatever you like.  Your choice.

Do you need one?  Up to you or the person who installed it in the machine.  If you don't think it is doing anything then remove.  Or if it seems to be cooling a vital part of the computer then reinstall it.

Author

Commented:
I would not know whether the removal of AUX fan would make some parts on the computer hot or not until the computer begins to break down in the future.
The AUX fan came with the computer when it was purchased.
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018
Commented:
I would NOT remove fans that came installed in the computer. I have 3 in my Lenovo desktop.

Just replace the noisy fan. That should work and should not cause any issues.
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The AUX fan is an important component to keep your PC cool.
It will run at 0 to fast speed depending on the temperature.
Do not disconnect it.
If the noise bothers you then replace it with a quieter make / model same spec. fan.
Note that if it looks dirty with debris, then cleaning any debris from it's fan blades will make it quieter.
( you can use cotton tips to clean it )

Author

Commented:
@John,
I know that I can replace the fan.
The reason for my question was because I did not want to spent time & money to replace the AUX fan on almost 6 years old computer and did not seem necessary considering there is only one CPU, HD and DVDRW.
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
Manufacturers design cases and cooling as a unit. That is why I say do not disconnect it.

You risk damage even on an old computer.
If you think the sound has increased over the period of time since you bought it, then this is probably due to dust. Give some WD-40 to the middle of this fan. The sound will go away if it is due to dust.

This happened to my desktop aux-fan and this is how i treated it. The fan goes to quiet state as soon as u apply wd-40 :)

Author

Commented:
@Khalid
Since I vacuumed all the fans inside the computer, there seems to be slightly less noise overall.
But in comparison to modern desktop computers which are whistle quiet, these two fans (CPU and AUX) make loud noise.
I am going to keep it under the desk.
The vacuum cleaner may not reach the inside of ur aux fan but wd-40 can. Give it a try starting with aux-fan.
No need to do it for the internal fan.
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
It is not all that difficult. You really cannot remove a designed-in fan. Bad idea.

So either replace the fans with modern, quiet fans, or replace the 6 year computer (best idea) and get Windows 10 while you are at it.

Author

Commented:
Spray Car@Khalid
I sprayed WD40. Hmm ... it smelled good and reminded me of those days when I used to chase mosquito spray trucks during mosquito season when I was a little.
Anyway after spraying it on AUX fan and CPU fan, it made little difference although those  two parts looked like NEW!
I will just deal with the noise. It used to be like that when it was new anyway.
I could replace them, but then why bother? This computer is not worth $20 anyway.

Thank you all.
Scott CSenior Engineer
Commented:
That computer doesn't have an extra video card to generate more heat. You could probably get a way with leaving it out...not the best idea, or you could just leave the side off of the case and allow the air to flow around it.  Still not the best idea, but that should work.  Especially if you could point a desk fan on the open area of the case.  That way you would have plenty of airflow and not have to spend any money if you already have the desk fan.

Not sure why you don't want replace it.  Fans like that are only around $10.  Free if you can find a good one in a junk computer laying around.
Although I like to keep my equipment going far into its obsolescence, in this case I'd recommend unplugging (or cutting the wire to) the too-noisy Aux fan and hope that this action speeds the final demise of the computer. You can pick up a replacement, not-quite-so-obsolescent PC for a similar amount of time/effort that you'd spend finding and replacing the fan, possibly even for free since less sentimental people are throwing away computers of this vintage.

At most, I'd put a piece of cardboard over the Aux fan opening so the power supply fan can take over the case ventilation.

[Speaking as someone who only this year finally disposed of a stack of 486-based laptops.]

Author

Commented:
"486-based laptops" --- WOW! 486. I remember 386 days. Good old days. CPU models were much simpler than.
These days I don't even bother. So ridiculously many kinds with different number of cores particularly on Server CPUs.
It is all part of sales scheme .... thousands of dollars you spend on CPUs today ... 5 years later, they will be sold for a penny on Ebay if you can find a buyer.
I consider the onward march of Moore's Law to be a good thing, not some sales gimmick. But I'm a bit disappointed that the rapid increase in clock speeds in the late nineties did not continue so that we'd have TeraHZ computers today. Physics got in the way of that dream for now.

So what are you using this computer for? If it has some practical use because of some program that you're running on it, is it a candidate for migration to a VM? I still go back and visit some of my old computers as VMs because they have an application or two that I've never found a suitable replacement for (whether because no suitable replacement exists, or I didn't want to spend money, or I didn't want to spend time learning something new, considering how infrequently I used it).

I really appreciate the the memory of mosquito control spray. WD-40 doesn't hit that particular olfactory memory node for me, but I certainly exposed myself to (or was exposed to) various fluoro-chloro-carbons back in the day. Who didn't like the sweet smell of leaded-gasoline engine exhaust?
Since it is an old PC, the fan may run at max. all the time? this will be noisy.

You can control fan speed with SpeedFan:
 
http://download.cnet.com/SpeedFan/3000-2094_4-10067444.html

youtube guide:

https://www.youtube.com/watch?v=8VjdQStihsE

Author

Commented:
This computer has AMD athlon 64 CPU with 3GB RAM. I upgraded to Win10. Kids will be using it for Internet surfing and create some school related documents, ITune and photoshop.
I may replace CPU and AUX fans as they seem to to be creating a bulk of noise.
Replacing the fans may only be a partial resolution.  As Michael Best mentioned, it is probable that the motherboard on that computer does not have the means to slow down, speed up, or stop the fans by detecting the heat inside the case around the various components, so they are all just running constantly at the same speed.  You stated earlier:  "in comparison to modern desktop computers which are whistle quiet, these two fans (CPU and AUX) make loud noise."  Motherboards have quite a few heat sensors built into them and positioned at strategic points.  The main purpose has always been to detect a potential overheat and shut the computer down as a safeguard, but modern computers have the ability to turn fans off or slow them down if the temperatures are low.  You will most likely have used a laptop and been aware of the fan kicking in when the inside of the case heats up and the hot air needs to be exhausted.  Modern desktop PCs do the same.

Case fans are cheap, freely available in various sizes (usually in increments of 10mm eg. 70, 80, 90, 100mm), and are easy to fit using the thick screws.  They are freely available because they wear out, as you have found.  Get a good quality replacement and make sure it has a standard motherboard connector.  Some come with bare wires at the end.  Make sure that you observe which way the fan moves the air.  You want it to suck air OUT the back of the case, not IN.  If in doubt, connect it but don't mount it and, while keeping your fingers clear of the blades, hold your hand across either side of the fan to determine the air flow direction before screwing it to the case.

Some PC cases come with a fan on the front that sucks fresh air in and also one that sucks hot air out the back.  When people build their own computers they sometimes add too many fans, and the one on the front can cause too much air turbulence inside the case to the extent that the fan can't suck the air out properly.

It is possible that your computer came with software to control the speed of the fans but that you have disabled it.  This software would usually be available as a download from the motherboard manufacturer's support website along with other updates and utilities.  Take a note of the manufacturer and model of the motherboard and go to the manufacturer's site to see if they have such software, or install SpeedFan as suggested by Michael Best.
Top Expert 2013
Commented:
my 2 cts
many cases come with an AUX fan - this does not mean that it is needed; it is just an option.
if it is a branded PC, it may have been designed that way, and certainly for SFF cases you may not remove any cooling element.
if the PC is not branded - i would just remove or disconnect the fan, and install speedfan, to monitor the cpu temp for a couple of days
the reason that that fan makes much noise is that it is an 8 cm fan, that runs at coniderable higher revolutions per minute, than the Power supply fan, which is a 12 CM type

oiling fans is only a temporary solution -  and the problem will return in a couple of months -  and does not even help if the bearing is worn out

http://www.almico.com/speedfan.php
Before anything go into BIOS and make sure fan speed control is enabled.
Then see if it runs quieter.
Use speedfan as I suggested.
Then see if it runs quieter.
If the noise still bothers you then replace it with a quieter make / model same spec. fan as I suggested.
dbruntonQuid, Me Anxius Sum?  Illegitimi non carborundum.

Commented:
WD-40 is NOT a lubricant.

If you are spraying WD-40 or a lubricant at the fan you need to peel off the sticker on the fan to get at the bearing and then restick the sticker afterwards.  Most likely it won't restick.  Been there, done that, and I do NOT recommend the procedure.  It will work, very temporarily though, if the problem is a worn bearing (usually a sleeve bearing).  A worn (sleeve) bearing gives a high pitched squeal.  And you permanently fix the problem by replacing the fan.

Author

Commented:
There is no high pitched noise. They have  been just loud from day 1. On these particular  PCs, I have replaced CPU and AUX fans before when they made abnormal sound. Of course I went with quiter ones.
Top Expert 2013

Commented:
you can also replace it with a silent model, here a80 mm :
http://www.quietpc.com/80mmfans
Thank you sglee
Top Expert 2013

Commented:
sglee - you relise that we are interested in what you choose to do now?
so i invite you to post the result of all this info

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