# Dell CPU Fan very Loud



## david50015 (Nov 11, 2008)

Please help 
I have a dell Optiplex Desktop GX280 with a very very loud cpu fan. 
When I turn on it gives amber light but no boot, just the fan starts going mad. I have 
onboard graphics card. I have 
 Disconnected all drives and left only motherboard connected, 
 Reset bios  no luck 
The only thing is when I take the cpu out and leave cpu fan connected then the fan works fine (no loud noise) so I think it is not the fan  but the cpu or a the motherboard / mother board sensor. 
I would really appreciate some help as I dont have a clue what it could be. I dont get any beeps from the motherboard at all on boot-up with cpu or without. Motherboard power light goes on inside case. 
Please please any advise


----------



## dustyjay (Jan 24, 2003)

When you put the Processor back in you did make sure you cleaned off the old Thremal paste and reapplied new THermal Paste, right?


----------



## Gnomad (Oct 3, 2007)

Is this a full size or a slim profile computer? If it is a full size, does the heatsink look like this one?


----------



## david50015 (Nov 11, 2008)

Hi thanks for the comments back

dustyjay - yes I did clean off all the paste and reapplied but I unfortunately I got no joy still sounds really loud

Gnomad - no the heat sink doesnt look like that I believe it is a slim line one just like this one 

Computer 
http://cgi.ebay.co.uk/Dell-Optiplex-GX280-P4-2-8GHz-Desktop-1GB-DVD-40GB-XP_W0QQitemZ300268529811QQcmdZViewItem?hash=item300268529811&_trksid=p3286.c0.m14&_trkparms=72%3A1300%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

heatsink look likes this one with two gold pipes on the other side
http://www.impactcomputers.com/m5786.html#


Any help is really appreciated, thanks


----------



## david50015 (Nov 11, 2008)

Gnomad - no the heat sink doesn't look like that I believe it is a slim line one just like this one

Computer 
http://cgi.ebay.co.uk/Dell-Optiplex-GX280-P4-2-8GHz-Desktop-1GB-DVD-40GB-XP_W0QQitemZ300268529811QQcmdZViewItem?hash=item300268529811&_trksid=p3286. c0.m14&_trkparms=72%3A1300%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

heatsink look likes this one with two gold pipes on the other side
http://www.impactcomputers.com/m5786.html#

Any help is really appreciated, thanks


----------



## win2kpro (Jul 19, 2005)

It appears you have an Optiplex 280 SFF which has a BTX motherboard and uses a BTX cooling module with passive heatsink cooling, and a rear exhaust fan. 

If this is correct, check the front air intakes of the cooling module, and make sure they are not obstructed with dust/dirt. You may have to lift the module and clean the heatsink fins.


----------



## david50015 (Nov 11, 2008)

Hi thanks win2kpro - I have taken off the fan and heatsink and cleaned it through, but still the same issue

When you say front air intakes are you referring to the heatsink ?

I have also just tried something and I don't understand it

When I take off the heatsink and the cpu is on its place where it goes without the locking fastening clip enabled then fan is not loud

When I lock the chip using the locking clip then the fan makes the very loud noise ?

Could this be something ? or nothing


----------



## win2kpro (Jul 19, 2005)

No, if you are not locking the heatsink down against the processor heat spreader, there is no heat in the heatsink to dissipate that is why the fans doesn't speed up. You will burn up your processor trying to run the machine like that.

One of the problems with the 280 machines, was in a lot of the machines (I don't know about all) Dell used the Intel 2.8Ghz. processor with a Prescott core. The Prescott cored processors ran hotter and were harder to cool, and in my opinion were really not a good choice of processor to be used with the BTX form factor arrangement.

If the intakes on the fan module are clean, the heatsink is clean, and installed properly then I believe either one of three things is wrong. (1) The temperature sensor that controls the fan speed on the motherboard is defective, or (2) the cooling module is defective. (3) the rear fan is not operative (if a rear fan is installed).

I want to verify with you we are talking about a SFF machine. Does it open sort of like a suitcase laying on its side? There is no fan directly on the heatsink, the cooling fan is in the cooling module? Also, does this machine have a rear exhaust fan, and is it operative.


----------



## david50015 (Nov 11, 2008)

The case open upwards and yes I believe it is a SFF, it s this cpu fan that connects to the heatsink like the one that I have put in the link above. So the fan does connect directly onto the heat sink (with two screws). This cpu fan exhausts air out the back of the machine.

1) if it is the temperature sensor on the motherboard is there anyway I can test this to make that is what it is before I buy a motherboard
2) I am not sure what cooling module you are referring to as the only cooling I think it has is the heatsink and the fan that is making the loud noise
3) the cpu fan that is making the loud noise is the only fan that exhausts air to the rear


----------



## win2kpro (Jul 19, 2005)

I'm not sure exactly which model 280 you have since Dell built 5 versions of the 280.

Go to this page;

http://www.vicomelectronics.com/Dell-Optiplex-GX280-Motherboard-Y6281.htm

Scroll down and see if you can identify exactly which machine you have. Also, on the machine there should be a sticker with the exact model number, and service tag number. If you can post the model number and the service tag number we may be able to figure out exactly which machine you have.

If i recall correctly, Dell had numerous problems with the motherboards on these machines, and I believe at one time they had a recall to replace the motherboards, but I'm sure that recall has expired by now.

The market is currently flooded with these machines since many are now "off lease" and are priced very cheap.


----------



## david50015 (Nov 11, 2008)

Hi Yes I have checked - it is definitely a small form factor - SFF


----------



## win2kpro (Jul 19, 2005)

Is this a machine you recently purchased? Did the machine ever run without excessive fan noise?

These machines had a known problem with bad motherboard capacitors. If the machine ever ran (since you had it) without the excessive fan noise, you MAY have a motherboard with bad capacitors, which is not letting the thermal sensor sense the correct processor temperature, and is making the fan run faster to cool the processor.

I BELIEVE these machines came with both Celeron D and Pentium 4 processors (socket 775). If this is correct, if a socket 775 processor is not installed correctly, the machine will either fail to POST or overheat almost immediately.

Re-check the mounting of the processor to make sure it is fastened down correctly with the proper amount of thermal compound. If you are satisfied that the processor is installed correctly, then it is very likely that you may have a motherboard with defective capacitors.

If you decide to replace the motherboard, I would check with Dell and see the latest part number for a replacement motherboard. If you purchase a replacement motherboard online without knowing the latest replacement number, you may wind up with a board that will have the same problem.


----------



## david50015 (Nov 11, 2008)

hi i had the machine for about 2 years its been perfect up until now.

before the constant fan noise it use to get really loud like now but if i switched on and off it would sometimes go but now it is on everttime and i cant even boot.


----------



## win2kpro (Jul 19, 2005)

If I had to guess, I would guess the board has "gone south". I just had a Gateway in the shop with identical symptoms. By unplugging all the drives I finally got the machine to POST one time and after re-connecting the hard drive got it to boot to Windows one time. After it booted to Windows the fan slowed right down, and was almost silent.

As I previously stated the Optiplex 280's had a known problem with some boards having bad capacitors, as also did some of the Gateway BTX boards.


----------

