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    Creative Gigaworks S750

    Few days ago there was popping sound from subwoofer unit under minute after turning speakers on and then it went dead with control pod showing no power.
    Quick googling showed that in UK people have had these to blow fuses but 3,15A glass tube fuze under power cord socket is intact, and neither did 10A plug fuse trip even though it's probably faster to react.
    After taking unit out from under the table I tried turning power switch and unit's power LED blinks like in some search results of this speakers dying problem.

    After that I unscrewed about dozen screws and already opening unit's back for few centimeters showed bulging CapXons (HP 105C) in primary.
    There are no visibly burst caps but if you look second pic closely you might notice something on surface of PCB in its left side near smallest transformer.
    While scraping that gum for removing shrink wrap I took that third pic showing signs of sparking or flame from that shrink wrapped Su'scon.

    Fifth primary cap (CapXon KM 105C) along that smaller transformer belong to "standby" section whose power is controlled by power switch in back of subwoofer unit and which gives power for control electronics and control "console/pod" whose power button in turn activates main power with that blue relay.
    All secondary caps are from CapXon GS serie. That one tiny cap in secondary along that "sparky" and little one next to standby's primary cap are Su'scon SL

    While having been bought/made in 2003 I've used so much headphones that I wonder if these speakers have even over 500 usage hours (and at very moderate sound level) meaning basically those caps expired all by themselves.
    With that high quality circuit board material and very good soldering someone should be shot for then going dirt cheap and using such junk time bomb caps!

    As no fuse was blown and there aren't signs of blown up semiconductors being responsible for that noise there should be decent chances for other components being intact.
    Any suggestions for highest quality caps to replace these junks?

    Audio/amplifier board caps are all Jun Fus but those really shouldn't be stressed by current except two Jun Fu HK serie caps in power rails.
    Attached Files

    #2
    Re: Creative Gigaworks S750

    Judging by the damage in that area there's a good chance that the optocoupler is shot too. If it doesn't power up after replacing the caps, drop in another opto as well. You can find several in any spare ATX power supply.
    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: Creative Gigaworks S750

      ^2 on the opto.
      It also looks like the glue on the board went conductive.
      Remove all of the glue, recap with Pan FC or FM's.
      Check diode D26 for being open or shorted (out of circuit).
      Stupidity should be a crime, especially for drivers. I have NO patience for them.

      Comment


        #4
        Re: Creative Gigaworks S750

        Glue that turned conductive over time also did some nasty things to the Enermax Liberty PSU series.
        "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
        -David VanHorn

        Comment


          #5
          Re: Creative Gigaworks S750

          At least neither end of opto is shorted and same goes for D26 which seems as normal as it's possible to say without detaching it.

          Four 470uF 200V (22x36mm) primary caps are snap in models and standby's 68uF 450V cap is equally high but normal leaded. (18mm diam.)
          Also 40mm high ones could just fit in without removing heatsink but it's probably best to avoid decreasing gap between capacitors and heatsink for allowing better airflow.
          What would be good capacitor series for these "job positions"?


          Originally posted by delaware74b View Post
          It also looks like the glue on the board went conductive.
          Lovely how thoroughly Chinese copied also work quality from "east neighbour" (pretty much literally, border is under ten km away) along with political system...

          Comment


            #6
            Re: Creative Gigaworks S750

            Originally posted by EsaT View Post
            What would be good capacitor series for these "job positions"?
            I just look at what series was already there, then match it to a series of a decent brand.

            But right next to those heatsinks you might want something better..
            "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
            -David VanHorn

            Comment


              #7
              Re: Creative Gigaworks S750

              Wasn't even intending to use just equally rated parts... although I suspect life time etc specs of those cheap China caps being all exaggerated just like advertising specs of cheap PSUs.

              DigiKey just doesn't seem to list/stock many top specced Japanese capacitor series so that with size limits seems to limit options rather well for primary caps:
              Nichicon GU or Panasonic TS-HB for 470uF/200V main caps
              Chemicon KXG for standby's 68uF/450V (also 82uF would fit)

              In secondary height isn't that limited so that gives options there, like Chemicon KZE and Nichicon HE for secondary caps of main rails.
              In case of same capacitance being not available from top serie would it be OK to use step bigger capacitance?


              BTW, What's the experience with Sam Young NXBs? I have two years old LG W2600HP IPS monitor with power supply full of those and I would like it to last until OLED monitors (or if FED/SEDs ever get out before that) are reasonably priced.

              Comment


                #8
                Re: Creative Gigaworks S750

                Guess it's time for update as I've now gotten forward in investigation.

                Standby's switcher is TOP243Y (seems instact as that LED blinked indicating some life and nothing is shorted between legs) and that little Suck'scon which gave fart connects to its control leg/pin (where opto is connected) through resistor.
                There's basic single diode rectifying for transformer's outputs and then L7920, L7908, L7809 and L7824 regulators in "secondary" heatsink.

                Opto's emission end seems to be burned broken as forward voltage should apparently be 1,2V typical but nothing shows on multimeter in either direction.
                L7824 is shorted between input and ground and this is also the rail monitored by opto so looks like same spike took out both. My guess is that Suck'scon's failure spiked outputs enough to zap these two parts.
                L7920's input-output shows 800 ohms but there's at least 1kohm resistor in between them so that's not yet entirely sure sign of failure.


                In addition next to Standby's primary cap there's one "Resistance is futile." 1N4004FS friode with 0ohm/0V to both directions but despite of its position in there I'm not yet sure what's its function: Cathode is connected to ground and anode is apparently connected to also main bridge rectifiers one leg and trace continues also to main power's relay contact. (have to remove those other primary Crapxons for better view)

                Comment


                  #9
                  Re: Creative Gigaworks S750

                  Some multimeters aren't able to test LEDs, and that includes optos. Try measuring a red LED with your meter and see if it lights up and/or shows any reading. If it doesn't, then your meter isn't adequate for testing the opto, but replace it anyway.

                  1N4004, change with 1N4007. I can hardly believe they still use the lower rated ones, it might be that it's the only diode of that kind on the board, coz sourcing 1N4004s AND 4007s would be more expensive than getting 4007 alone. True, the 4007 has a bit higher forward voltage, but i'm 90% sure it doesn't matter in there.
                  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


                    #10
                    Re: Creative Gigaworks S750

                    According to A817's datasheet typical forward voltage is 1,2V which is well within 2V range of Metex 3640.
                    Three Q817B marked optos I stripped from old failed Enermax show 0,95V @ ~1mA measuring current which fits to datasheet.
                    Good thing I didn't throw that junk away when getting it five years ago as failed old CWT (other primary CrapXon bulged and 5Vsb dead) I got last summer from PC of friend's family doesn't have any optos.


                    And looks like that friode really is in power input for standby after all:
                    In standby's primary copper plane surrounding everything on top side is positive rail and on bottom side it's ground.
                    But just why would they have put additional diode there straight after bridge rectifier?
                    If its supposed to function as some kind of protection it obviously failed to work that way.

                    Comment


                      #11
                      Re: Creative Gigaworks S750

                      Mmm, so it's on the INPUT side, ie the AC side? Interesting. Are you sure its cathode (band) doesn't lead to an inductor? Standby supplies are low powered enough to use a humble 1N400x for a rectifier, though i don't think that's what it does.
                      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


                        #12
                        Re: Creative Gigaworks S750

                        So, I've been having issues with my Gigaworks s700 which is basically identical to the s750 where it won't power on unless I run a blowdryer on the open boards for 20 minutes, then it clicks for a bit then finally powers up.

                        Following this and the other thread I replaced the 4 CapXon 470uF-200v HP Vent 105C caps with the recommended MCE ED 105C 470uF 200v caps from digikey, everything is still the same.

                        I am now thinking that the bad cap could be the 5th cap labeled CapXon KM 105C (C346), but I can't seem find a reference to a good replacement for this one. Any suggestions?

                        Also, any suggestions on how to locate which cap is needing replacement, it has proven difficult to located it by directing the blow dryer

                        Thanks!

                        Comment


                          #13
                          Re: Creative Gigaworks S750

                          Originally posted by SeattleMatt View Post
                          it won't power on unless I run a blowdryer on the open boards for 20 minutes

                          I am now thinking that the bad cap could be the 5th cap labeled CapXon KM 105C (C346), but I can't seem find a reference to a good replacement for this one. Any suggestions?
                          Check the CapXon KM datasheet and find out what ESR and ripple ratings it's supposed to have. Then find a replacement with the same or better specifications.

                          Originally posted by SeattleMatt View Post
                          Also, any suggestions on how to locate which cap is needing replacement, it has proven difficult to located it by directing the blow dryer
                          Top of the list would be an ESR meter. ESR drops when capacitors are warmed up, so a marginal one can get working when heated. If you check ESR when cold, and compare to the datasheet you will know if it's bad.

                          Or, you could use something with a finer nozzle and heat capacitors individually...

                          Bear in mind that it may not even be a capacitor, though. Heat affects many things. You might have a bad electrical contact\solder joint somewhere that's expanding and making contact when heated, for example.
                          "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                          -David VanHorn

                          Comment


                            #14
                            Re: Creative Gigaworks S750

                            Originally posted by SeattleMatt View Post
                            Also, any suggestions on how to locate which cap is needing replacement
                            Replace all CapXon capacitors. They are notorious for going bad, even the tiny ones!
                            CapXon KM is general purpose 105C rated caps, so pretty much any 105C-rated cap from the reputable manufacturers (United Chemicon, Nichicon, Rubycon, and Panasonic) should work fine.

                            Also make sure to remove any conductive glue if there is any on your board. Inspect all solder joints as well. If any seem suspicious, resolder them.

                            Comment


                              #15
                              Re: Creative Gigaworks S750

                              Thanks for the replies, I'm digging through data sheets now, I don't know very much about these so I feel like I'm shooting in the dark, can anyone recommend a specific cap?

                              Comment


                                #16
                                Re: Creative Gigaworks S750

                                Originally posted by SeattleMatt View Post
                                Thanks for the replies, I'm digging through data sheets now, I don't know very much about these so I feel like I'm shooting in the dark, can anyone recommend a specific cap?
                                What are the specifications of the capacitor you want to replace?
                                "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                                -David VanHorn

                                Comment


                                  #17
                                  Re: Creative Gigaworks S750

                                  Originally posted by Agent24 View Post
                                  What are the specifications of the capacitor you want to replace?
                                  the 5th cap labeled CapXon KM 105C (C346)

                                  Comment


                                    #18
                                    Re: Creative Gigaworks S750

                                    Originally posted by SeattleMatt View Post
                                    the 5th cap labeled CapXon KM 105C (C346)
                                    Need to know uF, voltage, dimensions

                                    Comment


                                      #19
                                      Re: Creative Gigaworks S750

                                      Well, i just fired this thing up again like i did before, using a hairdryer, it almost powered on, started switching on/off as usual, then suddenly one of the MOSFETs exploded! Now I'm starting to worry that I won't be able to revive this unit.

                                      Now I am looking for a Mosfet, it's labeled IRF740 I*R 343E 6E A3, can't seem to find this exact numbering anywhere.

                                      Also, now that I have it apart I can read the 5th cap info: Capxon info, 450v, 68uF 450V
                                      Attached Files

                                      Comment


                                        #20
                                        Re: Creative Gigaworks S750

                                        Those resistors are probably bad now too (R30 and R38)

                                        Comment

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