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

Discussion in 'Dell' started by William R. Walsh, Jun 26, 2009.

  1. Hi!
    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

    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.
    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.)
    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.
    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.
    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 R. Walsh, Jun 26, 2009
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  2. Hi!
    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.
    I'm certain it is not program or processor related then.
    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'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.
    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

    William R. Walsh, Jun 27, 2009
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  3. William R. Walsh

    S.Lewis Guest


    replacement Dell fan assembly is <$30 on ebay.
    S.Lewis, Jun 28, 2009
  4. William R. Walsh

    S.Lewis Guest


    Just dead. There's never a time when it will stop spinning when functioning
    S.Lewis, Jun 30, 2009
  5. William R. Walsh

    Charles Guest

    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, Jun 30, 2009
  6. William R. Walsh

    S.Lewis Guest

    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

    S.Lewis, Jun 30, 2009
  7. Hi!
    Shut down time! Don't use the computer again, it will cook. Perhaps it won't
    be instant, but it will cook.
    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 R. Walsh, Jul 1, 2009
  8. Hi!
    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.


    * 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.
    William R. Walsh, Jul 1, 2009
  9. William R. Walsh

    olfart Guest

    look at
    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
    olfart, Jul 1, 2009
  10. Hi!
    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.
    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 R. Walsh, Jul 1, 2009
  11. William R. Walsh

    Ben Myers Guest

    You really are 100% better off using a fan with a Dell part number and a
    custom 3-pin connector. The Dell part number for the entire assembly of
    fan, mounting bracket and green thingie is 02x585. These are cheap and
    easy finds on eBay... Ben Myers
    Ben Myers, Jul 7, 2009
  12. William R. Walsh

    Ben Myers Guest

    Right. The motherboard BIOS has built-in safeguards to prevent the CPU
    and board from burning out due to excessive heat, and there is no way to
    override the fan detection circuitry unless you want to do your own
    hacked BIOS.

    It is nearly impossible to match the exact characteristics of Dell fans
    except with other Dell fans... Ben Myers
    Ben Myers, Jul 7, 2009
  13. Hi!
    Well, not to sound harsh or rude or anything, but numerous people here
    (myself included :)) said "go with a Dell supplied fan". There is a reason
    for that.

    You put a fan in that doesn't have a tach lead, so the BIOS has no idea
    whether the fan is running or not. This is not something you can readily
    disable as it is a safety feature to prevent the system from burning out.
    The message implies that the Dell BIOS will only accept a given range of
    speeds in order to consider a fan to be "good". Zero (which is what the BIOS
    sees) is not going to pass that test.

    I'm not sure why you want to just diddle and hack around when the proper fan
    unit is inexpensive, readily available and should be very easy to install
    (in most cases). It really has me baffled, when the right answer is, well,
    right there.

    The PC will "run", but it's never going to be happy about not seeing a valid
    reading on the tachometer line. Also, the Dell fan has a thermal bulb so
    that it can sense increased heating and speed up accordingly. Your new fan
    doesn't, and if it doesn't move more than enough air all the time, the
    computer could still overheat. (Though this is unlikely, it could happen.)

    Please just go and get the Dell fan. Make your life easy and the computer
    happy once again.

    William R. Walsh, Jul 8, 2009
  14. Hi!
    I've never heard of this. Being a business box, it could have some
    Dell specific management software present. That software may have been
    intentionally made difficult to remove so that users wouldn't play
    with it or shut it down when it bugs them.

    You could probably find out approximately where it is located by
    bringing up the Task Manager when next the dialog box appears
    complaining about the fan. Leave the dialog box on the screen, go to
    the "Applications" tab in Task Manager and right click the entry
    representing the dialog box (hopefully it shows up).

    Choose "Go To Process". The responsible process will be highlighted in
    blue on the "Processes" tab. Search the computer for that program, and
    an uninstaller might show up nearby. (I would not recommend you just
    delete it, however.)
    Well, if you say so. You could have had a Dell fan delivered from just
    about anywhere by now. I'm not sure how you value your time, but at
    this point I think the cost difference between any Dell fan and the
    third party fan you got has been nullified.

    William R. Walsh, Jul 8, 2009
  15. William R. Walsh


    Mar 7, 2012
    Likes Received:
    Dell Optiplex GX620 noisy CPU fan and wiring

    Dell Optiplex GX620 noisy CPU fan.
    I just changed the fan and use again
    only those Rubber Fan Mounts and old fan's connector.
    New fan is
    Scythe Slip Stream 120mm PWM 4 pins
    You can buy from eBay adapter
    x2 Motherboard 4Pin To Dell 5Pin(4 wires) Adapter Cable Wire Converter
    I made wiring myself and I use old fan connector.

    old connector goes.
    pin 1 yellow or white sense
    pin 2 red +12V
    pin 3 black ground
    pin 4 blue control
    pin 5 empty empty

    New fans cables

    cable 1 black ground
    cable 2 red +12V
    cable 3 yellow sense
    cable 4 blue control

    so you can see Dell use special wiring order.
    Bios recognize fan and fan is working fine.
    Check picture from eBay if you don't believe me.
    roikkalamppu, Mar 7, 2012
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