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    #1

    Ideq dbvbe

    I'm an IT guy who works w/ computers every day. I don't normally deal w/ component level problems. I've been dealing w/ a lot of these shuttle size systems w/ small cases and blown caps. Generally they either won't POST which is what this one does, or they POST and immediately lock up.

    I've been having a discussion w/ some of my coworkers. I've always worked on the theory w/ caps that if they're bulged or leaking they're bad. Even if they aren't bulged or leaking they may still be bad. Others who know far more about board level electronics insist the caps are just a filter and the system should run fine w/ them bulged/leaking. From what I understand, the caps where these are located help control the voltage to the processor. Is this correct, and what would be the consequences of having these caps in this condition?



    This board won't POST so left to my own devices I'd say this board is bad and needs to be either recapped or replaced. I'm looking for the technical reason to tell a boss as to *WHY* the system won't work in this condition.

    Thanks in advance to anyone who takes the time to look at this and reply.
    Last edited by jhereg; 10-22-2010, 03:41 PM.
    Tags: None
    #2
    Re: Ideq dbvbe

    I like your choice of thread title. By the looks of those caps, they aren't just bulged, they are OPEN!

    That means that all the electrolyte has escaped from inside and evaporated, which makes the caps just decorations. They do not filter anything anymore. Read about ESR and its importance in switching power supplies, i don't think anyone here feels like explaining it again. Then you'll understand why and have a good answer for anyone that might ask.
    Originally posted by PeteS in CA
    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
    A working TV? How boring!

    Comment

      #3
      Re: Ideq dbvbe

      Originally posted by Th3_uN1Qu3 View Post
      I like your choice of thread title. By the looks of those caps, they aren't just bulged, they are OPEN!

      That means that all the electrolyte has escaped from inside and evaporated, which makes the caps just decorations. They do not filter anything anymore. Read about ESR and its importance in switching power supplies, i don't think anyone here feels like explaining it again. Then you'll understand why and have a good answer for anyone that might ask.
      They're definitely open. 3 of them have pushed the bungs out the bottom. Some of the others are completely vented on top and you can see inside.

      I've been reading about ESR and what it does w/ switching power supplies, but I've been at a disadvantage since I've got a boss who did electronic work (mostly w/ radios / phones) and I don't know how to explain it to him that these are nailed to the perch dead in a way he'll accept.

      Comment

        #4
        Re: Ideq dbvbe

        Just say they have an increased esr and heavily decreased capacitance due to the vaporization of the internal electrolyte and they must be replaced for the computer motherboard to fuction properly. Thatll do it

        Comment

          #5
          Re: Ideq dbvbe

          Leaving the caps in that condition will leave the PCs in the same non-working condition. The electrolyte is gone, and the caps may also shorted internally. I had 3 of these all with the same problem.
          Ludicrous gibs!

          Comment

            #6
            Re: Ideq dbvbe

            Originally posted by shovenose View Post
            Just say they have an increased esr and heavily decreased capacitance due to the vaporization of the internal electrolyte and they must be replaced for the computer motherboard to fuction properly. Thatll do it
            I wish. His theory is they are not necessary to the operation of the mb. I've been told they'll work w/o it, and if it won't POST/run to find another reason why it doesn't.

            Comment

              #7
              Re: Ideq dbvbe

              whats with the title?
              btw the capacitors are completely vital! it will cause cpu burn-outs, system instabiltiy, and a shitload f other problems

              Comment

                #8
                Re: Ideq dbvbe

                Originally posted by jhereg View Post
                I wish. His theory is they are not necessary to the operation of the mb. I've been told they'll work w/o it, and if it won't POST/run to find another reason why it doesn't.
                COMPLETELY incorrect. All you have to do is send him a link to these forums, or recap a non-working one and SHOW him the light.
                Ludicrous gibs!

                Comment

                  #9
                  Re: Ideq dbvbe

                  There was an old thread on here (with pictures) where this one motherboard's mosfets burned (literally!) due to bad caps. Obviously the board didn't work at all after that and was much harder to repair.
                  I can't seem to find that thread right now, though, but I found a few similar ones...

                  https://www.badcaps.net/forum/showth...ghlight=mosfet
                  (for some reason, the picture in that thread doesn't zoom in, so here's a direct link to it):
                  http://img216.*************/img216/4...pandmosfet.png

                  ... And another motherbaord with a bad mosfet from bad caps (3rd picture down).
                  https://www.badcaps.net/forum/showpo...&postcount=184
                  Note the burned ATX connector as well - common issue when the Fuhjyyu caps in old Antecs
                  went bad.

                  If this is not enough to convince your boss, I don't know what to say. Perhaps dood is right, just give him a link to these forums and let him see for himself.

                  Comment

                    #10
                    Re: Ideq dbvbe

                    Originally posted by jhereg View Post
                    Others who know far more about board level electronics insist the caps are just a filter and the system should run fine w/ them bulged/leaking.
                    .
                    "Others" would then be best described as A PACK OF MORONS!
                    .
                    VERY doubtful they have any actual training in REAL electronics. The subject would be covered EARLY in any real electronics training.
                    -
                    Filter caps remove Ripple Voltages [aka Noise, aka Static, aka EMI] from the DC power supplied to various IC chips.
                    The only difference between Ripple Voltage and the other kinds of noise are it's source and it's typical frequency.
                    It's adverse affects on electronics are the same.
                    -
                    IC chips include: The CPU, the RAM, the Chipset, the Memory Controller, along with all the smaller concerns like HDD controllers, Sound, LAN, Video, and add-in slots.
                    -
                    IC chips can not produce a stable output when their power and reference voltages are jumping all over the place.
                    This 'noise' will be superimposed over the top of any Data Signal output from a chip.
                    [Data Signal meaning 1's and 0's which physically are high and low voltages sent from one chip to another.]
                    The Ripple voltage adds to or subtracts from [depending on instantaneous polarities] the signal pulse.
                    The result is a garbled [corrupted] Data Signals because the superimposed noise results in some 1's becoming 0's and in some 0's becoming 1's.
                    - - Bad caps can affect anything on a mobo including things that get blamed on something else.
                    - They can result in corrupt data on hard drives because the data was garbled on it's way through the HDD controller. [HDD gets blamed.]
                    - Good RAM will give RAM errors, not because the RAM is bad but because the signals can't get to/from it. [RAM gets blamed.]
                    Lots of other examples...
                    -
                    The source of this Ripple Voltage is switching transistors that turn on-off rapidly to control voltages.
                    Each time they 'switch' there is a small voltage spike. These spikes are the Ripple Voltages.
                    The typical Ripple frequency is in the range of 50kHz to 200kHz.
                    [MOSFETs are common a type but they are just one type of switching transistor used on motherboards.]
                    These switching power transistors exist in the Power Supply, in the CPU voltage regulator [aka VRM], in the RAM voltage controller, there are several for the Chipset as well as maybe a dozen simpler single IC regulators scattered about the board.

                    .
                    Originally posted by jhereg View Post
                    From what I understand, the caps where these are located help control the voltage to the processor. Is this correct, and what would be the consequences of having these caps in this condition?
                    ""Is this correct"" -- Kind'a sort'a.
                    Those particular caps have two jobs.
                    -
                    Job #1 is to remove [filter out] Ripple created in the VRM [CPU voltage regulator] from the VRM 'output' so the power to the CPU is 'clean' DC.
                    There should be some 16v caps nearby. They are part of the VRM. They filter PSU noise out of the 'input' to the VRM.
                    A VRM is basically paired MOSFETs [or pairs of groups of MOSFETs] arranged such that when one is 'on' Vcore voltage goes up [MOSFET connects Vcore to +12v momentarily], when the other is 'on' Vcore voltage goes down [MOSFET connects Vcore to ground momentarily]. There is a controller chip that turns them off and on. They switch on-off so fast Vcore can be held at some voltage between ground and +12v.
                    This [filtering] job is dependent on the capacitor's ESR.
                    A failed cap has high ESR which prevents filtering and keeps the Ripple Voltage in the power.
                    - If the caps aren't doing this job any signals passing through or coming from the CPU can be corrupted with noise/ripple.
                    - The RAM may not be able to 'talk to' the processor.
                    - The processor may be unable to process it's own signals internally.
                    -
                    Job #2 is smoothing the voltage changes during load changes. [Like when CPU goes from 25% to 100% or similar.]
                    This is where the cap's 'battery like' characteristics come into play.
                    This job is dependent on the caps capacitance [uF]
                    A blown cap will have low [or no] uF and it's storage capacity [no pun intended] is reduced or nonexistent.
                    - A good sized load change would be enough to cause the CPU [and system] to crash.
                    - It can also cause boot-looping. - Repeated crash and reboot.
                    - If the caps don't charge at all it can prevent start-up completely.

                    ^^ As long as that is, it's still only the basic idea. Lot more to it.

                    .
                    Originally posted by jhereg View Post
                    This board won't POST so left to my own devices I'd say this board is bad and needs to be either recapped or replaced.
                    It absolutely needs recapped.
                    Either that or write it off and replace it.

                    Originally posted by jhereg View Post
                    I'm looking for the technical reason to tell a boss as to *WHY* the system won't work in this condition.
                    Print this and hand it to him.
                    .
                    Last edited by PCBONEZ; 10-22-2010, 09:01 PM.
                    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: Ideq dbvbe

                      looks like the msi boards i have to cap first thing when i get back.all vrm input and output caps blown open.no surprise it wont post.
                      got a bunch of itox boards to do that are blown up the same way.ncc kzg.

                      Comment

                        #12
                        Re: Ideq dbvbe

                        Originally posted by PCBONEZ View Post
                        .
                        "Others" would then be best described as A PACK OF MORONS!
                        .
                        VERY doubtful they have any actual training in REAL electronics. The subject would be covered EARLY in any real electronics training.

                        ...


                        It absolutely needs recapped.
                        Either that or write it off and replace it.


                        Print this and hand it to him.
                        .
                        That's exactly the info I needed. Unfortunately you get nowhere telling a boss they're a moron, so I'll use the info you gave me to support my cause. Like it or not I have to be diplomatic about it. Thank you.

                        Comment

                          #13
                          Re: Ideq dbvbe

                          You should replace all the KZG caps.
                          That particular series has a habit of failing without bloating at all.
                          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

                            #14
                            Re: Ideq dbvbe

                            Originally posted by shovenose View Post
                            whats with the title?
                            btw the capacitors are completely vital! it will cause cpu burn-outs, system instabiltiy, and a shitload f other problems
                            I missed this earlier. The title is the model number which is printed on the back of the case. it's an iDeq computer which is the same form factor as most of the Shuttle PCs.

                            Comment

                              #15
                              Re: Ideq dbvbe

                              lol ok it seemed like you just wrote random letters

                              Comment

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