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    what tool identifies bad caps on live circuit?

    can anyone recommend a not-so-expensive tool that will show me if a capacitor is bad? I have a bunch of Dell GX 620s that do not POST, and replacing the caps that clearly looked bad was not enough (some work now though). I think the tool is called a ESR meter or something, but I guess I just need some clarification on what and how to use.. thanks
    Last edited by speg_head; 06-30-2010, 05:22 PM.

    #2
    Re: what tool identifies bad caps on live circuit?

    ESR meters cost anywhere between $40 and $70 (my guess).

    You can search these forums for reviews of ESR meters and how people like them.

    Originally posted by speg_head
    can anyone recommend a not-so-expensive tool that will show me if a capacitor is bad?
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      #3
      Re: what tool identifies bad caps on live circuit?

      not on a live circuit.
      only a scope will help there.

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        #4
        Re: what tool identifies bad caps on live circuit?

        i think he meant the scope and as far as i know those are waaaay too expensive.

        at least thats what they used to tell me at school haha probably just to keep our hands off of em
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          #5
          Re: what tool identifies bad caps on live circuit?

          well new, they are expensive.
          however, with the collapse of industry in the west, there are shitloads on ebay and the surplus market for very little now.
          the same goes for lots of other pro tools.

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            #6
            Re: what tool identifies bad caps on live circuit?

            Well i was just under the impression that the ESR worked On a live circuit lol thanks for clearing it up though. Ill go check them out cuz ~$50 is definitely doable for me.

            Edit: so what should i be looking for when using the esr meter that will tell me that a cap is going bad?

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              #7
              Re: what tool identifies bad caps on live circuit?

              there is a rough value a good cap will show,
              if it's higher then the cap is bad, if it's lower it may be shorted inside.

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                #8
                Re: what tool identifies bad caps on live circuit?

                Using an ESR meter in a live circuit may damage the meter. Perhaps you are looking for an ESR meter that reads capacitors in circuit without pulling. All the popular meters do. Some caps are unreadable in circuit due to nearby components.
                sig files are for morons

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                  #9
                  Re: what tool identifies bad caps on live circuit?

                  Testing caps in a live circuit is a bad idea.

                  Testing caps in a dead circuit (without removing them) will not tell you 100% if they are bad.

                  To fully test a cap you need to remove it from the circuit and test the ESR and capacitance (2 tests and yes one can be good and the other can be bad).

                  A good ESR meter will test both.

                  A good multimeter will test capacitance (if it has that function).

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                    #10
                    Re: what tool identifies bad caps on live circuit?

                    Using an ESR meter in a -live- circuit -WILL- damage the meter.

                    In SOME CASES you can use an ESR meter for 'in circuit checks'.
                    [Which means a de-energized circuit with no components removed.]
                    - BUT - If there are any caps in parallel with the cap under test then checking with an ESR meter still requires removing the cap from the circuit.

                    GX620 in SFF and USFF are known for blowing some of the the 4mm and 5mm caps in addition to the typical cap problems. [They get too hot.]
                    https://www.badcaps.net/forum/showthread.php?t=6055

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                      #11
                      Re: what tool identifies bad caps on live circuit?

                      Do caps leak clear looking gunk like silicon?Seen plenty of the brown stuff but opened a power supply today and there was this stuff.Replaced main power caps and one domed 1000uf 16v job that were leaking
                      Tests and runs fine.


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                        #12
                        Re: what tool identifies bad caps on live circuit?

                        Probably was silicon.
                        They use it to hold parts in place for machine soldering.
                        Clear silicon is a little unusual. Usually see white/beige/brown.
                        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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                          #13
                          Re: what tool identifies bad caps on live circuit?

                          Originally posted by kiddznet View Post
                          Do caps leak clear looking gunk like silicon?Seen plenty of the brown stuff but opened a power supply today and there was this stuff.Replaced main power caps and one domed 1000uf 16v job that were leaking
                          Tests and runs fine.
                          Asking this question in this thread = no no.

                          Open a new tread for questions unrelated to the topic or you will most likely get no help.

                          Comment


                            #14
                            Re: what tool identifies bad caps on live circuit?

                            Originally posted by brethin View Post
                            Asking this question in this thread = no no.

                            Open a new tread for questions unrelated to the topic or you will most likely get no help.
                            Probably true, however,,,
                            When they gave you the badge did they issue a pistol that shoots used Fuhjyyu too?
                            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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                              #15
                              Re: what tool identifies bad caps on live circuit?

                              I would delete the post but I cant find the edit button?


                              939 DualCore AMD Opteron, 1800 MHz (9 x 200)
                              Abit AN8 / Fatal1ty AN8 SLI Series
                              3072 MB (PC3200 DDR SDRAM)
                              ATI Radeon HD 4300/4500 Series (1024 MB
                              Lian LI Aluminium mesh case

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                                #16
                                Re: what tool identifies bad caps on live circuit?

                                Originally posted by kiddznet View Post
                                I would delete the post but I cant find the edit button?
                                Don't worry about it.
                                The edit button goes *poof* after a few minutes.
                                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: what tool identifies bad caps on live circuit?

                                  a few being 10 minutes...

                                  clear goop is not unusual, it is essentially hot glue used by some companies instead of silicone. I have seen it in deer made units... powmax crap as well.

                                  what brand were the ones you opened up?
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                                    #18
                                    Re: what tool identifies bad caps on live circuit?

                                    depends, if it's wet then it's fresh electrolyte.

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                                      #19
                                      Re: what tool identifies bad caps on live circuit?

                                      The unit with the goop was a CODEGEN 300W
                                      Maybe a tool for detecting bad caps could be the "MK 8 Eyeball?"


                                      939 DualCore AMD Opteron, 1800 MHz (9 x 200)
                                      Abit AN8 / Fatal1ty AN8 SLI Series
                                      3072 MB (PC3200 DDR SDRAM)
                                      ATI Radeon HD 4300/4500 Series (1024 MB
                                      Lian LI Aluminium mesh case

                                      Comment


                                        #20
                                        Re: what tool identifies bad caps on live circuit?

                                        sounds like the power supply could be a junker, codegen tents to make over hyped gutless wonders... some pics if you could get them would be nice...
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