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Re: Loud (not noisy) CPU fan in my dad's Dell Optiplex GX260 machine.

 
 
William R. Walsh
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      06-26-2009, 05:38 PM
Hi!

> Does anyone have any ideas why my dad's old Dell Optiplex
> GX260 machine's CPU fan is loud (not noisy) in blowing?


Weeell...where I come from "loud" is roughly equivalent to
"noisy". :-)

What kind of a sound is it? Is it air rushing, or is it a rough and
gritty kind of loud?

Rough and gritty is a bad fan. Air rushing is probably the fan
speeding up to meet some kind of increased heat demand from the CPU.
It could be that there is software stuck in a loop and consuming all
idle processor time.

Or you could just have a Pentium 4 Prescott, as I did in my Dim8300.
That machine would wind its way up to "vacuum cleaner" with great
regularity. I changed it to a Northwood P4 and the noise drop was
stunning.

Dell fans have a thermal sensing bulb on them that will increase fan
speed as the air going by gets hotter. The motherboard supplies full
fan voltage all the time, leaving it up to the sensor on the fan as to
how fast it should be turning.

> I checked the CMOS to see if I could get fan readings or
> control, but didn't see one.


There is a tach lead coming off of the fan and going to the
motherboard. The Dell BIOS knows if the fan is running--so it *can* be
sensed. The problem is, nobody (not even Dell, based on a conversation
I had with a Dell employee) knows how this is done. The fan sense
inputs on the LPCIO are left unconnected if it has them. Most Dell
systems use an LPCIO that doesn't support fan speed monitoring.

(Gee, does it sound like I've been looking into this or what?)

The secret as to how Dell laptops monitor their fans and control them
has been at least partially revealed. SpeedFan and i8kFanGUI can
monitor the fans in many Dell laptops. i8kFanGUI can even change them.

The OptiPlex GX620 (note: not a 260) desktop will show fan speeds when
"Dell Notebook Support" is enabled in SpeedFan's preferences. What's
more, when SpeedFan goes looking for fans, it causes the CPU fan to
speed up. After a lot of testing here, this is the first Dell desktop
system I've found to report fan speeds in a similar method to the
laptops. (I should have tried i8kFanGUI on the GX620, but I didn't and
it has no OS on it now.)

> We noticed the interior and fans don't look that dusty/dirty (amazed
> at that compared to my PCs after all these years).


A PC is a good indicator of the air quality in a home. I've seen PCs
that came from spotless homes that were filthy inside and ones that
came from (shall we say) "less clean" homes that were surprisingly
clean inside.

> Any ideas? Do we need to replace it? Both PSU and CPU fans
> seem to be blowing fine. Just CPU fan is LOUD and blowing hard.


The thermal sensing bulb may be bad (shorted) and causing the fan to
run at full throttle. This is impressively loud. I think some Dell
fans could hurt you at full throttle, if you stuck your fingers in
there. They put almost all other computer fans to shame. :-)

Dell spare parts should have the fan you need. It's special because of
the built in speed control and sensing bulb--a regular replacement fan
is likely to just run at full speed all the time and be loud. Or
noisy. :-) The price should be reasonable.

> I wonder if this is related to the low voltage battery error in CMOS
> a few months ago (haven't seen it since then). I told him not to
> take the CPU fan parts apart because he might make it
> worse.


Replace that battery while you're there. It's cheap (about $3) and
good insurance against it leaking. It's got to be getting close to its
intended lifetime by now.

William
 
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William R. Walsh
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      06-27-2009, 06:45 AM
Hi!

> Air rushing. Remember those CPU fans that you can control speeds? Louder
> at faster RPM, quieter at lower RPM. It's like that but at very fast
> speed. Maybe maxxed out?


Yes, it sounds like it is running at full throttle.

Many of today's motherboards have fan speed controllers built in. Some of
them are even pretty good, and a few more can even be "taken over" with the
right software.

> That's the thing. The PC was just powered on after being off all day or
> so. We even idled at CMOS/BIOS screen!


I'm certain it is not program or processor related then.

> > Or you could just have a Pentium 4 Prescott, as I did in my Dim8300.
> > That machine would wind its way up to "vacuum cleaner" with great
> > regularity. I changed it to a Northwood P4 and the noise drop was
> > stunning.


> How do I change that?


You'd change the processor. But I don't think it is the problem--the system
must have a bad fan. I mentioned it as an interesting sidebar.

Prescott and Northwood were both different versions of the Pentium 4. The
Northwood was a pretty competent CPU that didn't get excessively hot. On the
other hand, Prescott Pentium 4 processors were supposed to perform well and
I suppose they did look good on paper. In reality, they consumed lots of
power, threw off lots of heat and couldn't perform as well as the Northwood
did at the same speed. The later LGA775 (socket type) Prescott processors
were better than the Socket 478 ones.

Intel ran into something of a dead-end with the Pentium 4 family. They
dumped a lot of work and doubled back to the Pentium M (which itself was a
hopped up Pentium III) to come up with a better idea. That better idea is
today's Core/Core2 Solo and Duo processors. You can still buy the Pentium D
and Pentium 4 though.)

> I wonder if that is why we got CMOS/BIOS warning about low voltages a
> few weeks ago/a month ago. Related?


I'm sure the battery is probably starting to get weak. It's only used when
the machine in unplugged or without power. Without any power, the lifetime
is supposed to be three years.

> So I can't use a custom fan like for custom built PCs?


No. The connector is different, although that is the least of your problems.
You can hook up a standard fan and it will promptly run at full throttle.
Most fans don't have an onboard thermal sensor to control their speed. They
let the motherboard and its fan controller decide the speed that should be
chosen. Dell did it the other way around and specified a fan with its own
built in thermal sensor.

Look the fan over and you will see a "bulb" coming out of one side of the
hub.

William


 
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S.Lewis
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      06-28-2009, 02:36 AM

"Ant" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) m...
> On 6/26/2009 11:45 PM PT, William R. Walsh typed:
>


<snip>

replacement Dell fan assembly is <$30 on ebay.


 
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S.Lewis
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      06-30-2009, 01:57 PM

"Ant" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) m...
>A status update since the CPU fan just stopped a few minutes ago, but the
>PC is still working (no reboots, no lockups, no crashes, etc. yet!).
>
> Not sure if the CPU fan is dead though. PSU fan is still spinning, black
> CPU fan is not spinning at all, but we can see it shaking/vibrating (not
> sure if it is from it or the PSU fan -- can feel air flows from both
> vents). Not sure if it is trying to spin or just dead.


<snip>


Just dead. There's never a time when it will stop spinning when functioning
normally.


 
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Charles
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      06-30-2009, 04:56 PM
Ant wrote:
> On 6/30/2009 6:57 AM PT, S.Lewis typed:
>
>>> A status update since the CPU fan just stopped a few minutes ago, but
>>> the PC is still working (no reboots, no lockups, no crashes, etc. yet!).
>>>
>>> Not sure if the CPU fan is dead though. PSU fan is still spinning,
>>> black CPU fan is not spinning at all, but we can see it
>>> shaking/vibrating (not sure if it is from it or the PSU fan -- can
>>> feel air flows from both vents). Not sure if it is trying to spin or
>>> just dead.

>>
>> <snip>
>>
>>
>> Just dead. There's never a time when it will stop spinning when
>> functioning normally.

>
> Darn. Would this be a motherboard issue (capticators) or just the CPU fan?


SHUT IT DOWN, then get a replacement fan for it. Continued use w/o the
fan will destroy the processor from the excessive heat.

Charles
 
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S.Lewis
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      06-30-2009, 05:31 PM

"Ant" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) m...
> On 6/30/2009 6:57 AM PT, S.Lewis typed:
>
>>> A status update since the CPU fan just stopped a few minutes ago, but
>>> the PC is still working (no reboots, no lockups, no crashes, etc. yet!).
>>>
>>> Not sure if the CPU fan is dead though. PSU fan is still spinning, black
>>> CPU fan is not spinning at all, but we can see it shaking/vibrating (not
>>> sure if it is from it or the PSU fan -- can feel air flows from both
>>> vents). Not sure if it is trying to spin or just dead.

>>
>> <snip>
>>
>>
>> Just dead. There's never a time when it will stop spinning when
>> functioning normally.

>
> Darn. Would this be a motherboard issue (capticators) or just the CPU fan?
> --




Judas H. Priest, man.

By my count, this is the third time I've suggested just replacing the Dell
fan assembly with a similar assembly off of ebay.

Now, it COULD be it COULD be the fan pin header on the system board, but I'm
sure you'd want to replace the entire motherboard first to determine that a
<$20 fan assembly is bad. ?

With all due respect, good luck to you.

I'm sure you'll get it fixed. I'm so out of this thread at this
point............


-Stew


 
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William R. Walsh
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      07-01-2009, 03:05 AM
Hi!

> A status update since the CPU fan just stopped a few minutes ago, but
> the PC is still working (no reboots, no lockups, no crashes, etc. yet!).


Shut down time! Don't use the computer again, it will cook. Perhaps it won't
be instant, but it will cook.

> Not sure if the CPU fan is dead though. PSU fan is still spinning, black
> CPU fan is not spinning at all, but we can see it shaking/vibrating


It's an attempt to get started up again. The idea is that if the fan is
stuck, it will "rattle" and hopefully break free. In this case, I would
imagine you've lost one of the sets of magnetic coils in the fan.

Dell spare parts may carry the fan. I don't know the price, and I know that
their web site is not always really clear about what you will get when you
order. Even if you don't do eBay, a friend might. You will have no problems
if you buy from a reputable seller (been around a while, good feedback
profile (look at comments AND percentage)).

William


 
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William R. Walsh
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      07-01-2009, 03:16 AM
Hi!

> I wonder what software I can use to control the fan issue in this Dell
> PC. Any ideas?


I already spoke of this in the post you are replying to. To recap:

1. No known software can control Dell desktop fans or report their speeds.
2. The Dell BIOS knows if the fan is turning. Whether it knows how fast the
fan is actually going, I cannot say.
3. The LPCIO IC on the motherboard frequently has no fan speed
monitoring/control support OR it isn't hooked up*.
4. Conversations I've had with Dell suggest that nobody there knows how it
is done. I suspect I just haven't talked to the right people.
5. Selected Dell laptops *will* report fan speeds and support limited
changes using a tool like i8kFanGUI.
6. The fan speed is controlled *internally* by the fan itself. There is a
thermal bulb on it that senses the temperature of air as it goes by. The fan
receives its full operating voltage from the motherboard.

William

* the lone exception to this (that I know of) is the Precision 220
workstation, which has functional fan speed monitoring that can be tapped
into with a tool like SpeedFan.


 
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olfart
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      07-01-2009, 05:57 AM

"Ant" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> And, the fan spins at full speed again for who knows how long after
> powering on for today! I did tell my father to not to use the PC when the
> CPU fan stops again like last night to avoid heat damages to the old CPU.
>
> I hope to get the fan and/or motherboard replacement this long weekend.
>
>

look at www.pcexchange.com
you can probably get another GX260 cheap and use it for parts if your Dad
wants to keep his running. I bought a 260 a while back for a friend. very
reliable dealer


 
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William R. Walsh
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      07-01-2009, 02:27 PM
Hi!

> Is that magnetic coil what caused the fan to go full throttle
> before it stopped?


The fan has malfunctioned internally. Multiple parts of its circuitry
are likely to be bad. One failure in an electronic device can lead to
cascade failures. Look at it this way--instead of just silently
failing, it gave you an audible warning that something was wrong.

The magnetic coils in the fan are used to make it turn around and
around. There are multiple sets. One or more have failed, leaving the
fan only able to twitch.

Without that, you might have only found out when the machine started
crashing. And then you'd have found the toasted CPU, bloated
capacitors, and ruined computer.

> OK. I guess it might be a fan issue only.


Numerous people who know have said that. :-)

It is *extremely* unlikely that the motherboard is bad. All you have
to do is get a fan--one way or another--hook it up and pop it into
place. I couldn't see it taking more than ten minutes. It's a special
fan, so it will need to come from Dell, a third party retailer that
has one, or from a scrapped system.

William
 
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