Dimension C521 power switch - not turning on

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Dimension C521 power switch - not turning on

  • I have a Dimension that will not turn on.  When I plug the unit into an outlet the CD drive flashes, the processor fan makes a noise and the light for Aux Pwr LED turns on.  However, when I push the power switch nothing happens.  The diagnostic lights do not light up nor does the power switch.  The unit was purchased in Jan 2007 so it is out of warranty but was working fine until recently.  I have tried unplugging all of the peripherals and tried starting the computer but to no avail.  I have also reseated the RAM.  There are no noises when trying to start the computer.

     

    Is it possible for a power switch to go bad?  Or should I be concerned about the power supply itself?

     

    Thank you.

    Message Edited by dyounce on 05-12-2008 04:24 PM
  • That it does the powerup cycle when plugged in demonstrates that it is not 'dead'.  That's good.

     

    Do you feel a physical click when you press the button?  The physical switch seldom fails (though it can), but in the 5xxx chassis there is an ongoing issue with the bezel button misaligning with the switch such that it does not actually press it. This can sometimes be resolved by loosening the screw directly above the button on the inside edge of the chassis, holding down the bracket and retightening the screw.

     

    If you DO feel a physical click, confirm that both ends of the connector going to the switch board are firmly seated. 

  • dyonce:

     

     

    I just registered for this forum, and I was glad to see your posting, I have a Dimension 4600 that has a very similar problem. I spent almost half a day on line with a tech (probably in India) trying to solve the problem - no luckHowever, I am handling the problem anyway - I simply do not turn my computer off.

     

    One difference may be that if I use the "restart" feature from the START button, the computer does restart. I thought that this meant that I had a really small problem, but I still can't get it fixedWhen we went on vacation for about a month, I did turn my computer offTo get it started again, I removed the side panel and used a hand held hair dryer to warm up the inside. After a while, this seemed to work and the computer came did turn on.

     

    I am still trying to find out if the computer has a small "back-up" battery for the automatic start-up feature, but haven't learned the answer to that either. My older computers did have such a battery, but I cannot find one on this model. (I used to "assemble" my own computers from parts that I purchased, but that became uneconomical.) 

    Maybe someone else will help us both.

    Up2Hugh

     

  • dyounce

    It could be either, but more likely it's the power supply

    When you opened the case to reseat the memory, did you check that all the cables, are properly connected?

    If you are comfortable around computers, you could try the following to test the power supply.

    Unplug the cord from the power supply, hold the power button in for about 15/20 seconds, open the case, unplug the 24-pin power connector from the motherboard and jump the Green wire to one of the Black wires, reconnect the power cord and power the system on, if power supply fan and hard drive run, then the PSU should be good.

    Note: Do not remove any wires from the plug, use a small piece of wire or a paper clip as a jumper.

    Bev.


    ===================================================
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    Post the issue in the appropriate Board, where they will be answered.

     

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    Forum Member since 2001
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  • Thanks for the responses!

     

    I checked all of the cables.  I had unplugged them for testing purposes and had plugged them back in securely.  The cables had no indication of failure or any burnt marks.

     

    I lifted the heat sinc so that I could "adjust" the i/o panel.  As a matter of fact, there wasn't a "clicking" noise when I was pushing the button so I thought that it might be possible that the switch was misaligned.  The machine was able to start (I don't have it hooked up to a monitor yet so I don't know if anything is on the screen) but the power button stays amber with no diagnostic lights.

     

    I will repost when I am able to hook up to a monitor - but I really don't know why the power button is a constant amber and am frankly concerned since what I could find was a statement about a pre-post failure.  That doesn't sound good.

  • The switch won't make much sound.  You feel it more than hear it.  Yellow power light is not switch misalignment.  It's power failure.

     

    Remove all plugin cards, to eliminate those.  If nothing changes, it's one of 3 things, and odds are divided up pretty evenly.  Power supply failure, motherboard regulator failure, capacitor failure on the front panel board.

     

    The FP board is cheapest, but as it only has one capacitor and everything else has many, it's least likely the cause.  Power supply is next cheapest to replace, and it that doesn't fix it you will have a spare power supply for testing next time, and the motherboard will have to be replaced. 

     

    The interconnectedness of the system makes it impossible to determine which component has failed without substituting new ones.

  • dyounce

    The Dimension C521 systems use a Dell proprietary power supply, due to it's shape.

    You can buy a replacement from Dell Spare Parts, or from eBay here, also here

    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 plugged the machine in and fired it up.  The power button still stays amber.  The monitor flashes no video and the computer will not shut down by holding in the power button.  As the machine is firing I still believe that the power supply is good but the issue is with the m/b or the i/o front panel.

    Message Edited by dyounce on 05-15-2008 01:21 PM
  • Replaced the m/b and the front panel.  Pressed the power button.  Machine started but the power button was amber and the video was not recognized.  Couldn't turn it off so I had to unplug it.  Now it won't even turn on.  I tried a replacement power supply from another working C521 model and that didn't work either.  At a complete loss.  It is now an expensive paperweight.  Any thoughts on what I might be missing?
  • Oy!  Replaced MB and frontpanel, substituted known-good PS, and it STILL won't start?

     

    Are there ANY parts you can remove/disconnect that haven't been replaced?  All accessory cards.  All USB except mouse and keyboard.  Even all drive power.

     

    The reasonable assumption at this point is that either something that hasn't been replaced is bad, or the replacement motherboard is bad (new parts can be defective).

     

     

  • OK -the only thing that the power supply is plugged into is the motherboard.  Still nothing.  I have also removed the memory.  I was REALLY hoping that it was a simple solution :smileysad:
    Message Edited by dyounce on 05-20-2008 02:03 PM
  • I have the exact same problem "C521 will not turn on - plug the unit into an outlet the CD drive flashes, the processor fan makes a noise and the light for Aux Pwr LED turns on.  However, when I push the power switch nothing happens.  The diagnostic lights do not light up nor does the power switch.  The unit was purchased in Apr 2007 so it is out of warranty but was working fine until recently".  In reading all of the responses, I fail to see how the processor fan and CD light could function if the power supply unit has failed.  It would seem reasonable that the switch has failed.  On my switch I feel a "slight" click when pushed in but it changes nothing in terms of powering up. I do not see any screws to adjust alignment of the panel- it appears that the switch is built into the front panel and is entirely closed in.   How is this supposed to be replaced?

     

    Thank you.

  • If the switch (held to above chassis flange by one hex/Phillips screw) fails, you don't get fans or CD lights, you get nothing.

     

    Power has two principal rails, 5V and 12V.  12V runs the fan and CPU.  5V runs the drive logic.  If you get both fans and drives, the problem is not power, it is motherboard.