Dimension 8400 fan at hyper speed and no boot up

Desktop

Desktop
Desktop computer Hardware and Software discussion

Dimension 8400 fan at hyper speed and no boot up

  • Hi my dimension 8400 fan starts slow then builds to hurricane force blowing and the computer wont boot up. A capacitor was bulged out on the motherboard so I replaced the MB. Its still doing the same thing. So is this a heat sink problem or do i need a new power supply? thanks for the help in advance.
  • Fans running full tilt on an 8400 are an indication of a NO POST.
     
    Any indications from the POWER LED, or the DIagnostic LEDs on the back?

    Donald Kempf

    Inspiron E1505 /XPS 10 Windows 8

    Dimension 8400 Windows XP/Vista/8

    #IWork4Dell

  • It was a pretty common problem for the heatsinks to go bad (no way to visually tell though) on the Dim 8400 and PowerEdge SC420 and this would cause CPU temp to go up which in turn caused the temp controlled fans to run at full blast.
     
    However, in most cases that I've heard of the system would still boot up and run ok (just unbearably loud fan noise).  However, if you have a higher powered processor then that may explain the no post.  If you can verify that the CPU is working by trying it in another system then I would conclude that the heatsink is bad.
  • I am also having the same problem with my Dell Dimension 8400, P4, 3.0 ghz, 1 GB Ram.  It is approximately 3 plus years old.  About 2 weeks ago it started to accelerate the fan on start up and would not stop until I shut the computer off.  It is the CPU fan that is accelerating to hyper speed.  It will not boot when this happens.  Since then it has been intermittent.  If you open the case and blow out the dust, unplug the fan, plug it back in, say a few prayers, etc.. , it probably will boot, but the next time I go to start it up chances are the fan will begin accelerating again.  I also tried taking the heatsink off, cleaning with alcohol, reapplying thermal grease and reseating it.  I also tried to blow out all dust from the heatsink and air intakes.  It did not seem to change anything.  When the fan accelerates on start-up, the power light stays a solid amber.  The four diagnostic lights on the back do not do anything, so I assume it is a pre-bios failure.  When the machine does boot properly the four lights on the back all display solid green.  Next, I tried removing and reseating memory.  That did not solve the problem either.  When I have a component removed (memory, graphics card) the fan accelerates - I have never been able to get it to boot or show diagonstic lights when the memory or graphics cards were removed.  When the fan is unplugged it will not boot at all either.  With the graphics card removed, I thought I heard a faint beep pattern of (1-2-1) but I am not sure if this is correct.  The manual said that would be a Programmable Interval Timer problem.  I have no idea what that is.  Any hellp from anyone out there would be great,  I read another thread with a similar problem and the conclusion was that if the diagnostic light s did not show anything when cards and memory were removed it was probably a motherboard failure.  Anyone else think this is the case?  Would a motherboard failure be intermittent like this?
     
    Thanks.
     
  • laf123
     
    Try replacing the heatsink.
     
     
    Bev.
     
     
     
     
    ===================================================
    Please don't send me questions about your system by DCF Messenger.
    Post the issue in the appropriate Board, where they will be answered.

     

    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

  • I had read those links already, about the possibility of it being the heatsink.  I was unable to find the exact Dell part (W4254) for much less than $100 which seemed exorbitant.  So, I purchased a third party heatsink that was compatible with the LG775 socket (same as my computer) but when it arrived I realized the spacing of the screws on the retnetion bracket would never fit in the Dimension 8400.  Also, the fan cable was the wrong pin configuration.  Anyways, I became doubtful of the heatsink becasue the problem occurs immediately on startup.  The CPU has not even had a chance to get warm, so I didn't think there was an oppotunity for the computer to think that heatsink was not doing it's job.  If anyone knows where I can get a new Dell heatsink that will fit in the Dimension 8400 for a reasonble price, I'm willing to give it a try, but I thought the noisy fan issue in the other thread was occuring after the computer was on - and those people didn't seem to have a problem with the computer not booting at all. 
     
  •  
    Bev.
     
     
     
     
     
    ===================================================
    Please don't send me questions about your system by DCF Messenger.
    Post the issue in the appropriate Board, where they will be answered.
     

     

    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

  • Thanks so much for the link to the Dell Spare Parts - I don't know why I didn't find that before - The heat sink was only 12.95 - I'm going to give it a try.  I'll post back with the results after I get it.
     
  • laf123
     
    Pleased to have helped.  $12.95 is an excellent price.
     
    Bev.
     
     
     
     
    ===================================================
    Please don't send me questions about your system by DCF Messenger.
    Post the issue in the appropriate Board, where they will be answered.

     

    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

  • Thanks, I called and ordered a heatsink. we'll see how that works.
  • sponkos  
     
    Good Luck.
     
    Bev.
     
     
     
     
    ===================================================
    Please don't send me questions about your system by DCF Messenger.
    Post the issue in the appropriate Board, where they will be answered.

     

    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

  • Well, the new heat sink did not work.  I removed the old one, cleaned the surface of the processor with alcohol.  Reset the new processor which came with the thermal paste pre-applied.  The first boot worked no problem.  The second time I booted, same problem as usual.  Power light stays amber.  No diagonostic lights at back of machine.  Fan continues to rev faster and faster until the power button is held in to stop it.  I am dissapointed but not surprised.  It didn't seem like it could be the heat sink if the computer failed to boot with a cold processor.  It was worth a shot though.  Does anyone else have a suggestion?  Is this a motherboard issue?  Again, it is an intermittent problem. And typically after putting the cpu on it's side and opening up the box it will boot.
     
    Any other sugestions are appreciated.  It isn't a bad machine otherwise and I'd like to keep it in service.
     
    Thanks.
     
  • I have a similar problem with the constant amber light.  It only started happening after I installed two new 1GB ram modules -- a matching pair of Samsung RAM of the same model as the original dell samsungs that came with my system.
     
    I only got the hyper speed fan once, but I have had the constant amber light exactly as you've described either when I go to turn the system on or when it freezes when I'm in the middle of something.
     
    I thought it might be the new ram, since that's the only change, but I don't understand why it would work some of the time and pass all the memory diagnostic tests, then choose to lockup randomly.
     
    I have found a reliable way to fix the constant amber light using dell's online troubleshooting wizard -- basically they tell you to disconnect the two cables that go from the power supply to the motherboard and then reconnect them (doing this without the power cord attached, of course).  For some reason, this works and the system will startup but then randomly later on it will freeze or just not startup.  It could be 1-2- or even 7 days later.  I don't understand what is causing it or event what to replace.
     
    Any thoughts?
  • I read the descriptions with amazement.  I have a Dimension 8400 that has for probably more than a year had the vacuum cleaner startup fan problem.  It was intermittent making it hard to troubleshoot.  Dell sent me a heat sink first, I replaced it.  It seemed better for a while but started up again and they sent a technician to replace the fan.  Seemed better for a while.  Lately it has in increasing frequency of no startup, vacuum cleaner fan and I have to hold the start button 10 seconds to shut off.  Another observation is it sometimes freezes and goes to the deadly blue screen intimating that my ATI graphics stuff is in an endless loop.  I don’t recall a relationship between this freeze up at first but lately when this happens I would shut down and with restarting the vacuum cleaner is back.  A week ago I got new thermal paste and no problem for one week.

    ?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 

    So yesterday the fast fan stopped being intermittent, the fan is taking off every startup.  I tried about everything I read about in the forum.  I got the fast fan even with the RAM out and with the video card out.  It is now out of warranty and the service person was not as willing to help but with pointing out that they had documentation of this same problem they went through troubleshooting. 

     

    So we do a lot of the same things that I did already.  Then one step further, she has me remove the heat sink then remove the CPU.  Then put it back in.  There was no clear reason why she wanted me to do this.  Then while I was on hold I tried turning it back on and … it turned on.  The main difference was removing the CPU.  I turned it on and off several times and it worked.  I thanked the tech person closed the case, turned it back upright (was working on it lying on its side).  I plugged it in and without pressing the start key it turns itself on (only the vacuum fan) and revs up just like before!  Tech support says get a new computer…

     

    I try several things and it still whirrs with start up.  So I take out the CPU and put it back in and it works again!  So I am thinking it is something positional or an electrical contact.  I stand it up and it does not start.  I think I will lay it down and inadvertently lay it down with the motherboard up.  This gets me vacuum cleaner.  So I turn it over (without getting inside the machine) and now it is working again. 

     

    It seems like a positional thing related to the heat sink and the motherboard.  I don’t get it.  But I will keep it on its side while shopping for something new. 

     

    If I get a new motherboard from http://www.centrix-intl.com/results.asp how do I know which one to get?

     

    Thanks all…

  • I'm happy (in some ways) to hear of others with similar problems.  We swore that it was working better on it's side so it's interesting to hear someone else with the same issues.  My next step was to try the power supply.  I was thinking that the right volts weren't being sent to the motherboard.  I will see what happens to pull and reset the cpu.  It might buy me another boot because right now I'm getting nothing.
     
    Thanks.
     
    I'll keep everyone posted on what keeps happening with ours.