Dimension 8400 cpu/heatsink cooling fan

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Dimension 8400 cpu/heatsink cooling fan

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I've owned this Dell for about a year (second owner)  and in the last three weeks the cooling fan for cpu/heatsink has taken a drastic change in its operation. When the pc is started, it starts relatively normal but over the next 10 to 15 seconds it seems to ramp up to its maximum speed (6000 RPM). I did a lot of reading and this fan isn't your typical type of a cpu fan (current rating is 2.3 A).For the last two weeks the pc has been "parked" as I will not continue to use it until this problem is resolved.

As someone who has quite a bit of experience in pc (both software and hardware), I did a lot of reading and searching. Following many advices I have exhausted my options and hope someone will be able to help me. In reading many threads relating to this specific problem I performed the following actions in order to fix my pc;

1.Cleaned the pc heatsink of any dust or air blokage (I make a point of monthly cleaning all my pc's) and therefore I did not expect this to be a cause for this problem;

2.There are no bulging or leaky capacitors on the motherboard;

3.There are no orange lights (diagnostic faults) on the back of the pc. All are green coloured;

4.Removed the cpu/heatsink assembly and cleaned the surface of both with isopropyl alcohol. Applied a fresh coat of thermal grease to cpu surface and reassembled the two;

5.In reading one of the other threads with the same problem I attempted to reverse the cpu fan . Rather than exhausting the air from inside the pc case, it's blowing over the heatsink but I still found the fan too noisy when it's running at full speed;

 6. I installed software to monitor both the cpu temperature and cpu fan speed and the only parameter outside its norm was the fan speed (< 5750 RPM);

In one of the threads, a community member ("shesagordie") suggested to replace the original fan with Zalman CNPS 7700-Cu . I have purchased the fan but after some analysis can not see how this fan can be inserted in place of the original. The Zalman mounting bracket is a standard  socket 775 where the original heatsink bracket is a proprietary Dell version. Drilling through a multi-layered board can only invite more trouble as it is too easy to damage one of the copper traces. The link that was provide on the Zalman installation leads to a 403 error>>

I am in Canada and there is no access to this server. If anyone would be kind to post the installation guide to another location, I would be very grateful.

Incidentally, my family owns three other Dell pc's (6400 Inspiron, Dimension 8300 and Dimension e510) and this is my first time I am seeking technical help.

 Thank you for your help.

 

 

 

 

All Replies
  • Bev.

    Yes indeed! They are the ones. I don't know why I thought they were not there.
    I already have the Dell fan attached to the back panel where it does a good job as an occasional case fan.
    I have a  pair of Noctua's mounted to the heatsink handling the heat (It doesn't look pretty inside the case I have to confess).

    Seems to work ok. I would much prefer the Zalman solution, so I will order one.

    Thanks for that.

    Bruce 

  • Bruce

    A few hints:

    You need to trim the base of several cooling fins to avoid touching the capacitors next to the heatsink and possibly adjust the cooling fins to stop them touching the power supply casing.

    Bev. 

     

    If my answer was helpful, please use the 'Did this answer the question' and click: Yes
    Forum Member since 2001
    I am not employed by Dell

  • If I may throw my 2-cents into this cauldron... Stick out tongue

    There is one other thing to think about with the 8400. When the nVidia video drivers on my 8400 aren't loaded, eg in Safe Mode or if they've gotten corrutped, the fans run and sound just like you described  (don't know if that's true with ATI video cards/drivers).

    So before you get too deeply into Zelman coolers etc, you might want to uninstall the video drivers in Device Manager, reboot and install the latest video drivers from the manufacturer's site (not from Dell who tends to be way behind in video drivers).  It might also be a good idea if you run Driver Cleaner Pro, assuming you can still find the freeware version somewhere, to make sure the old driver is completely removed before you install the new one.

    I have Dell's original nVidia GeForce 6800 PCI-e video card in my system and currently using nVidia driver v6.14.11.8585 (4-30-2009), if that's of any help...

    I do agree that you should probably install the proper heatsink retaining clips too.

    Ron

    If this answers your question, please click  Yes  

    Ron

    Forum Member since 2004

    I am NOT a Dell employee

  • Thanks Bev
    I may not be able to use it yet - the latest images on the Zalman site show the install kit without the brackets I need - seems they have covered it with a universal bracket. I will physically check when they are back in stock at my retailer.

    Regards

    Bruce 

  • RoHe

    I have done the video drivers.
    Using the latest available from ATI, and you are right, removing the drivers can be a arduous experience, but it has to be done.
    The problem is that the fan reacts well before the load of the drivers, even before it gets POST done which makes looking further down the process a waste of time. 
    About one in ten attempts gets me a clean boot. 
    The only job now is to manage the situation while I get another machine organised. 

    Bruce 

  • Same problem here guys.  Should I get the Zalman?  Which models can we use?

  • The Dim 8400 was/is plagued with bad heat sinks.  Dell had a problem with heat sinks going bad in the 8400.  The original 8400 heat sinks have small tubes containing some type of liquid for cooling and these tubes eventually leaked until empty thus causing the cooling fan to surge.  It happened to mine 4-5 years ago.  I replaced both the heat sink and cooling fan and ended my problem.

     

     

     

     

  • Hmm. Sounds great.  Wow.  Yeah that is crazy about there being liquid in the copper tubes that eventually evaporates or leaks out.  Which heat sink and fan did you use for the replacement?  Did you use the same Dell W4254?  And if so are you worried about the liquid leaking out again?  Is that an issue to be concerned about or not really?  I need to do the same but am unsure whether I should try using a Dell W4254 first or go straight for the Zalman CNPS7700.  The Zalman seems like there would be a lot more work involved to modify the brackets and get it to fit, but maybe would be worth it in the end due to it's essentially silent operation.  What did you do?  And what do you think I should do?

  • I purchased both a new heat sink and cooling fan on eBay that was specified for the Dell Dimension 8400.  I had no more problems with the cooling fan surging.  I recently sold the 8400---it would have been 6yo in December.

  • Alright I'll risk it.  I'll purchase the W4254 first and then if that doesn't work I'll go for the Zalman upgrade.  Thanks. 

    Oh man I'm nervous.  I hope this works.  I will post the results back here when it comes in.

  • Just make sure it's not "Revision 00". That was the first version and Dell replaced it with a later revision(s) over time.

    A "system pull" here for $20 + $6.85 S/H with 30 day warranty.

    Refurbished here for $30 (S/H, warranty?)

    Refurbished here for $60 wtih 90 day warranty (S/H?)

    Ron

     

     

     

    If this answers your question, please click  Yes  

    Ron

    Forum Member since 2004

    I am NOT a Dell employee

  • Thanks for the reply RoHe.  Check this out guys.  It looks almost as if someone has opened up the top of the pipes, refilled them, and then sealed them back up with solder.  Has anybody ever thought about trying to do this?  And what kind of liquid do you think is in there?  I've got the tools to do it and was thinking it might be worth a try.  But what kind of liquid would I use, antifreeze, or maybe the same type of liquid they sell for water cooled systems?  Any ideas? 

  • Have no clue what fluid is used.

    Why do you think it's been "refilled"? The one here also has 3 copper tops and 3 silver tops. Coincidentally it's exactly the same price and also with free shipping and comes with the brackets. Hmmm....

    And if you look closely at the photo in that link, you'll see the label says Rev A00. I pretty sure the one in my 8400 is Rev A01. Don't know if there's an even later revision, but my system dates to Nov-2004. You might call Dell Spare Parts and ask which is the latest revision number for that part. Idea

    There's a refurrbished one here that also has  3 copper tops and 3 silver tops...

    Caveat emptor! Wink

    Ron

    If this answers your question, please click  Yes  

    Ron

    Forum Member since 2004

    I am NOT a Dell employee

  • The reason I think they've been refilled is because the one that's in the Dell Dimension 8400 that I'm working on has all copper tops.  Even the solder or brazing that they used on the pinched tops is copper colored.  So being that leakage is a known issue with these heat sinks I think that they've all been refilled at some point in time.  Another possibility would be that the very first ones that were manufactured by Dell had this copper colored brazing on them, they then discovered there was some kind of defect there, stopped using it, and then started using the silver colored solder from then on.  Another thing to think about, brazing sticks melt at a much higher temperature than silver solder does.  Could it be that they stopped using it because by sealing the tubes with the brazing sticks it caused the liquid inside the tubes to boil off?  Crazy stuff.  And I don't think they'll ever be forthcoming about it.  This heatsink is also a REV A00.

  • Your guess is as good as mine...

    Even refilled/refurbished, I'd avoid Rev A00 if possible. You only want to replace that heat sink once in this lifetime! Geeked

    Ron

    If this answers your question, please click  Yes  

    Ron

    Forum Member since 2004

    I am NOT a Dell employee