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    Replacement Chemicon SMG caps

    Hi All,

    Ive just pulled apart a bowers & wilkins sub.
    The power board is covered in crappy chemi con SMG series caps. A couple are leaking and some others have ESR levels above manufacturer spec.

    Please any advice would be dearly appreciated. I want an alternative at least 105degrees longer life caps (the smg are 85 degrees 2000hrs)
    Ive been reading and getting more confused, ppl saying you need to match the same ESR and spec correctly.

    Ive attached pics - the little black caps are the SmG - not sure if i need low esr caps or general purpose etc
    Attached Files

    #2
    Re: Replacement Chemicon SMG caps

    None of those *appear* bad. As far as leakage, if you're referring to the white stuff around the bases of the larger ones, that's not leakage....it's glue.

    As a rule, UCC caps are pretty good, their only 'troublesome' series were KZG and KZJ.
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      #3
      Re: Replacement Chemicon SMG caps

      Ive tested all of the caps and a number are faulty.
      My main thing is a recommendation of which series of cap to go for in a brand like panasonic, nichicon, rubycon
      ( with at least 105 degrees and longer lifespan)

      Comment


        #4
        Re: Replacement Chemicon SMG caps

        i tend to just put panasonic FR in just about anything these days

        Comment


          #5
          Re: Replacement Chemicon SMG caps

          Originally posted by stj View Post
          i tend to just put panasonic FR in just about anything these days
          I approve this message.
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            #6
            Re: Replacement Chemicon SMG caps

            Originally posted by stj View Post
            i tend to just put panasonic FR in just about anything these days
            Thank you! Ill order some panasonic FR series for the recap (will there be any issues given that they are low esr?
            Anyone have any experience with the Panasonic EEUTA1 they are rated at an insane 125 degrees!

            Comment


              #7
              Re: Replacement Chemicon SMG caps

              philips make 135degree caps,
              i dont think the esr and ripple are good on the really high temp stuff though - they are generally intended for stuff like gas ignitor units.

              Comment


                #8
                Re: Replacement Chemicon SMG caps

                SMG is UCC/NCC's general purpose series, not low quality. And it looks to me like they are being used appropriately.

                That said, just about any of the good brands' non-aqueous low impedance series should do well:

                UCC/NCC LXZ series

                Panasonic FC series (is FR the newer non-aqueous low impedance series?)

                Nichicon PW or PA series

                Rubycon YXF

                These brands' long-life aqueous series are all excellent, but aqueous parts tolerate ambient heat a little less well, and these series' lower impedance is of no special benefit.

                So go with best price and availability of the series listed above, IMO.
                PeteS in CA

                Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
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                  #9
                  Re: Replacement Chemicon SMG caps

                  Originally posted by PeteS in CA View Post
                  SMG is UCC/NCC's general purpose series, not low quality. And it looks to me like they are being used appropriately.

                  That said, just about any of the good brands' non-aqueous low impedance series should do well:

                  UCC/NCC LXZ series

                  Panasonic FC series (is FR the newer non-aqueous low impedance series?)

                  Nichicon PW or PA series

                  Rubycon YXF

                  These brands' long-life aqueous series are all excellent, but aqueous parts tolerate ambient heat a little less well, and these series' lower impedance is of no special benefit.

                  So go with best price and availability of the series listed above, IMO.
                  FR is an aqueous series AFAIK, similar specs to HE. All very good caps. Since this amp used SMG, I would preferably stick with the same class of caps, but using higher temperature variants. KMG, NHG and VZ would be most appropriate choices for the intended design.
                  Last edited by pc7fan; 09-24-2020, 06:18 PM.

                  Comment


                    #10
                    Re: Replacement Chemicon SMG caps

                    Originally posted by PeteS in CA View Post
                    SMG is UCC/NCC's general purpose series, not low quality. And it looks to me like they are being used appropriately.

                    That said, just about any of the good brands' non-aqueous low impedance series should do well:

                    UCC/NCC LXZ series

                    Panasonic FC series (is FR the newer non-aqueous low impedance series?)

                    Nichicon PW or PA series

                    Rubycon YXF

                    These brands' long-life aqueous series are all excellent, but aqueous parts tolerate ambient heat a little less well, and these series' lower impedance is of no special benefit.

                    So go with best price and availability of the series listed above, IMO.
                    My neighbour has a friend who is willing to replace all of my caps free of charge with Rubycons YXG series caps (they are the only ones they have at his work). My apologies as I am a complete noob - and cannot fully understand the data sheets of the caps.

                    smg specs:
                    https://www.digikey.com/catalog/en/p...mg-series/3646

                    rubicon:
                    https://www.digikey.com/catalog/en/p...g-series/25454

                    the high and low frequency ripple currents appear to have significant differences in values between the SMG and YXG caps. Will it be an issue with stability or cause any issues if I replace all of the smg caps for the rubycon yxg?

                    (its for a b&w subwoofer power board and amp board both of which are covered with chemi con SMG caps, 3 of which are faulty) - both the smg yxg are labelled as general purpose.

                    thank you all for your kind patience
                    Last edited by hansy; 11-19-2020, 07:20 PM. Reason: more detail

                    Comment


                      #11
                      Re: Replacement Chemicon SMG caps

                      You will probably alright using them ( this would not be my first choice but might be a third choice but it cost that drive my choice ) my first choice is United Chemi-Con KY / KZE / LXZ or second choice FR / FC ( size diameter and height make this choice for me sometime ) I find that this brand of capacitor are higher in cost. The smaller UF under 100 UF value of capacitor I buy a hundred of them at a time

                      Sometimes it what device I am working on and what brand of capacitor are already installed sometimes make that decision for me if I can still find that series or not

                      Some Servo motor controller can be pick-e what type of capacitor that is used
                      Last edited by sam_sam_sam; 11-19-2020, 08:57 PM.
                      9 PC LCD Monitor
                      6 LCD Flat Screen TV
                      30 Desk Top Switching Power Supply
                      10 Battery Charger Switching Power Supply for Power Tool
                      6 18v Lithium Battery Power Boards for Tool Battery Packs
                      1 XBox 360 Switching Power Supply and M Board
                      25 Servo Drives 220/460 3 Phase
                      6 De-soldering Station Switching Power Supply 1 Power Supply
                      1 Dell Mother Board
                      15 Computer Power Supply
                      1 HP Printer Supply & Control Board * lighting finished it *


                      These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                      1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                      2 Hem Saw Computer Stack Board

                      All of these had CAPs POOF
                      All of the mosfet that are taken out by bad caps

                      Comment


                        #12
                        Re: Replacement Chemicon SMG caps

                        Originally posted by hansy View Post
                        My neighbour has a friend who is willing to replace all of my caps free of charge with Rubycons YXG series caps (they are the only ones they have at his work). My apologies as I am a complete noob - and cannot fully understand the data sheets of the caps.

                        smg specs:
                        https://www.digikey.com/catalog/en/p...mg-series/3646

                        rubicon:
                        https://www.digikey.com/catalog/en/p...g-series/25454

                        the high and low frequency ripple currents appear to have significant differences in values between the SMG and YXG caps. Will it be an issue with stability or cause any issues if I replace all of the smg caps for the rubycon yxg?
                        Should be fine.
                        I see that the picture of the PSU you showed is of the switching type. So if anything, YXG will probably do better than SMG due to having lower ESR... and also longer rated life.

                        Comment

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