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    #1

    GX620 desktop wont boot

    I have several Dell Optiplex GX620 desktops, not SFF or USFF. It has the amber blinking light and I tried unplugging all components and using another PSU but it still won't boot. This has led me to believe there is a capacitor issue but none of them show any of the usual signs, such as bulging or leaking. I have read that some of them can dry without showing and signs of issues but I don't know where to start.

    Should I just recap everything or would it be best to only recap the larger CAPs and go from there? I have read a lot about the SFF and USFF issues but couldn't find anything regarding the desktop form factor.
    Tags: None
    #2
    Re: GX620 desktop wont boot

    Next usual suspect is the PSU.

    Also check for 85C caps on mobo. .. The 4 & 5 mm caps.
    Those boards are Intel.
    Intel likes to use 85C caps sometimes.
    85C caps don't always last very long.
    Mann-Made Global Warming.
    - We should be more concerned about the Intellectual Climate.
    -
    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
    - Dr Seuss
    -
    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
    -

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      #3
      Re: GX620 desktop wont boot

      I already tried another working PSU and that didnt work. I checked and what do you know, there are 85C caps on it. I read about these over heating easier but these computers arent on much. Usually they are only on 3-5 hours a weekday. There are a bunch of 220uF, 4 2200uF, and 6 1800uF caps.

      Comment

        #4
        Re: GX620 desktop wont boot

        Still need to check old PSU.
        When a PSU 'goes' it can kill the motherboard's chipset.
        Mobo will then not start on a good PSU either.

        GX620 [in the small cases] are known for 'toasting' the small caps even when they are 105C rated.
        Blown 85C caps near heat sources like the CPU or chipset or MOSFETs are a possibility.
        There is really no way to check them short of an ESR and uF meter.

        Remove the heat-sinks from the north and south bridges [the chipset chips] and clean them with some isopropyl and Q-tips. Then when they dry inspect them closely for signs of melting and/or cracks, pits, or shiny spots. Any of those things can indicate a blown chipset. [Although a chipset can be blown with no visible signs.]
        - You will need some thermal paste or pads like used for CPUs to replace the heat-sink[s]. You may want to wait until you have some handy before you pull the heat-sink[s].
        - DO NOT run it without the heat-sinks installed!

        Inspect the MOSFETs for the same kinds if issues as the chipset.
        .
        .
        Mann-Made Global Warming.
        - We should be more concerned about the Intellectual Climate.
        -
        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
        - Dr Seuss
        -
        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
        -

        Comment

          #5
          Re: GX620 desktop wont boot

          You make some good points. Up until this point I have always been able to visually see a blown cap and been able to replace them. If the PSU went bad and took the chipset with it is it safe to plug it into another computer to verify whether the PSU is working? I don't want to damage another computer if it is the PSU.

          Comment

            #6
            Re: GX620 desktop wont boot

            I tried shorting the PSU to make it run and the fan came on. Does this verify the PSU is ok or can it still be bad? I also opened it up and didn't see any visual signs of damage.

            Comment

              #7
              Re: GX620 desktop wont boot

              I have a pile of relatively worthless P3 boards I use for that, as in wouldn't really be a loss.

              Either do a visual inspection inside it or use one of those PSU checkers.
              Preferably both before you connect it to another board.
              Those PSU checkers won't tell you if a PSU will run under a real load but it will tell you the PSU isn't going to ruin a board straight away.

              BEWARE: The heat-sinks inside a PSU can be energized by line power so have it unplugged from the wall when you are poking around in there.

              If you have some around you could also try attaching a few old hard drives as a load and jump the green wire [in large mobo connector] to any black wire.
              That should start the PSU then you can check voltages with a meter.

              .
              Mann-Made Global Warming.
              - We should be more concerned about the Intellectual Climate.
              -
              Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
              - Dr Seuss
              -
              You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
              -

              Comment

                #8
                Re: GX620 desktop wont boot

                Originally posted by TechGuy View Post
                I tried shorting the PSU to make it run and the fan came on. Does this verify the PSU is ok or can it still be bad? I also opened it up and didn't see any visual signs of damage.
                As you can see I type slow.

                Some won't start without a load and others will.
                - Once you have it on check the voltages with a meter.
                Mann-Made Global Warming.
                - We should be more concerned about the Intellectual Climate.
                -
                Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                - Dr Seuss
                -
                You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                -

                Comment

                  #9
                  Re: GX620 desktop wont boot

                  I just answered my own question about the fan indicating whether a PSU is working or not. I jumped a PSU with some blown caps and the fan still came on. I will further test the PSU. However, if the PSU is ok and I can't find any signs of damage on the chipsets or other components then is my next step to replace all of the caps?

                  Comment

                    #10
                    Re: GX620 desktop wont boot

                    I've forgotten which wire it is at the moment but there are pin-outs online.

                    Make sure you check +5vsb too.
                    That's where a lot of problems that blow chipsets come from.
                    .
                    Mann-Made Global Warming.
                    - We should be more concerned about the Intellectual Climate.
                    -
                    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                    - Dr Seuss
                    -
                    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                    -

                    Comment

                      #11
                      Re: GX620 desktop wont boot

                      I just remembered that I have an old P4 MoBo and I tested it with the PSU and it worked fine. I still want to test the PSU for the experience but does this mean I have to move on to replacing the caps if everything else seems ok?

                      Comment

                        #12
                        Re: GX620 desktop wont boot

                        Originally posted by TechGuy View Post
                        I just answered my own question about the fan indicating whether a PSU is working or not. I jumped a PSU with some blown caps and the fan still came on. I will further test the PSU. However, if the PSU is ok and I can't find any signs of damage on the chipsets or other components then is my next step to replace all of the caps?
                        Bad caps will give the PSU a noisy output but that isn't enough to blow the chipset.
                        You are looking for a voltage that is way out of spec or missing completely.

                        If all of the above doesn't ID the problem the next thing I would do is replace the 85C caps.
                        That's a shot in the dark because there's no way to know if they are good or bad.

                        There aren't any KZG caps on this board are there?
                        Intel sometimes uses them but not usually on the Dell boards.
                        .
                        Mann-Made Global Warming.
                        - We should be more concerned about the Intellectual Climate.
                        -
                        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                        - Dr Seuss
                        -
                        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                        -

                        Comment

                          #13
                          Re: GX620 desktop wont boot

                          I understand it is a shot in the dark now. I didn't see and KZG caps, just KZJ and others. Unless you have any other pointers I will plan on replacing the caps and see if that works. I am curious if you know how long it takes for a cap to dry out.

                          Comment

                            #14
                            Re: GX620 desktop wont boot

                            KZJ!!!
                            Replace those first.
                            - They fail without bloating. [Same as KZG.]
                            Mann-Made Global Warming.
                            - We should be more concerned about the Intellectual Climate.
                            -
                            Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                            - Dr Seuss
                            -
                            You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                            -

                            Comment

                              #15
                              Re: GX620 desktop wont boot

                              I am guessing you have dealt with these before. I will purchase these first and see if that fixes the issue. Thank you very much for your help. I have really appreciated it and it has been a great learning experience for me. I am still curious if you know how long it can take a cap to dry out though, just for future reference.

                              Comment

                                #16
                                Re: GX620 desktop wont boot

                                There is no definitive answer. Depends on too many things.
                                Many caps last 30-40 years or more. Some are lucky to make it to 3.

                                The materials that go into them play a big part.
                                - Caps made with CH or TW aluminum tend to die younger than caps made with JP or US made aluminum because the CH and TW stuff has more impurities.

                                The temperature plays a big part.
                                - Each 10C rise in temp reduces a cap's life by 1/2.

                                And there's other things like how good the rubber seal is and what chemicals are used in the electrolyte.

                                Intel's design criteria for mobos is that the shortest life component should last at least 7 years.
                                .
                                Mann-Made Global Warming.
                                - We should be more concerned about the Intellectual Climate.
                                -
                                Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                - Dr Seuss
                                -
                                You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                -

                                Comment

                                  #17
                                  Re: GX620 desktop wont boot

                                  Ok, thanks for the information. Hopefully, replacing the KZJs is all I need to do.

                                  Thanks again!

                                  Comment

                                    #18
                                    Re: GX620 desktop wont boot

                                    Turns out the KZJ caps were bad because after I replaced them the computer started up. Everything seems to be working fine now.

                                    Thanks for the help.

                                    Comment

                                      #19
                                      Re: GX620 desktop wont boot

                                      Congrats!
                                      Mann-Made Global Warming.
                                      - We should be more concerned about the Intellectual Climate.
                                      -
                                      Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                      - Dr Seuss
                                      -
                                      You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                      -

                                      Comment

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