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    need replacement transistor

    Hi,

    hoping someone can ID or suggest a replacement for one found in an antec EA-500 psu:


    6 4 7
    6 L 4

    e c b

    It's a TO-92 case, the second line of #'s are spaced more widely. It's in the 5vsb ckt., I busted a lead off trying to remove some of the tan glue from it's legs.

    #2
    Re: need replacement transistor

    Google

    It's probably a 2sb647

    e c b is the pinout; emitter, collector, base
    Last edited by SteveNielsen; 02-08-2016, 10:24 AM.

    Comment


      #3
      Re: need replacement transistor

      How is the Transistor connected to other components? Good clear pictures of both sides of the board?
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

      Comment


        #4
        Re: need replacement transistor

        Originally posted by SteveNielsen View Post
        Google

        >I did, tried bing, yahoo, digikey and mouser also, as well as alldatasheet

        It's probably a 2sb647

        >that may be it - at least they are both pnp's

        e c b is the pinout; emitter, collector, base
        Thanks Steve

        Comment


          #5
          Re: need replacement transistor

          Originally posted by budm View Post
          How is the Transistor connected to other components? Good clear pictures of both sides of the board?
          My good camera is down right now, it may be able to take a better pic of the bottom - the emitter was connect to R601 on the bottom of bd., (a surface mount one), the collector was connected to R602, (15 ohms) near the heatsink, right in the area where the purple wire is.

          I removed a 220uf 16v cap, which reads ok in esr and capacity. The transistor tests ok too, both diode junctions only read one way, about 640mV.

          Thanks Bud
          Attached Files

          Comment


            #6
            Re: need replacement transistor

            Their solder-wave must have been running cold, that blobby shit would have never made it past me when I did QA.

            Comment


              #7
              Re: need replacement transistor

              Originally posted by SteveNielsen View Post
              Their solder-wave must have been running cold, that blobby shit would have never made it past me when I did QA.
              It is pretty ugly, rather hard to make out which component's leg is sticking through where -
              I don't think it's been worked on before, I put all the scratches on it trying to get rid of some whitish powdery stuff that was between the traces in several places.

              Comment


                #8
                Re: need replacement transistor

                With Japanese transistor types, "2S" is usually omitted on the device markings, and I have seen some which also omit A/B/C/D markings.
                My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

                Comment


                  #9
                  Re: need replacement transistor

                  Originally posted by japlytic View Post
                  With Japanese transistor types, "2S" is usually omitted on the device markings, and I have seen some which also omit A/B/C/D markings.
                  Thanks for the info. I guess a comprehensive cross-reference book is a thing of the past now.

                  Comment


                    #10
                    Re: need replacement transistor

                    put the old one on a tester to see if it's npn or pnp etc.

                    Comment


                      #11
                      Re: need replacement transistor

                      Originally posted by SteveNielsen View Post
                      Their solder-wave must have been running cold, that blobby shit would have never made it past me when I did QA.
                      Hey Steve, just wondering can you tell me if the surface-mounted components are put on the board before, or after, it goes through the wave-soldering operation?
                      Last edited by xelectech; 02-09-2016, 09:56 AM.

                      Comment


                        #12
                        Re: need replacement transistor

                        A good video showing wave soldering
                        https://www.youtube.com/watch?v=Ap-HY7qP9zE

                        Comment


                          #13
                          Re: need replacement transistor

                          At :34~36 you can see she twisted the black heatsinks for the SMD ICs, so the SMD components were already went through the SMD process before the wave soldering process.
                          Never stop learning
                          Basic LCD TV and Monitor troubleshooting guides.
                          http://www.badcaps.net/forum/showthr...956#post305956

                          Voltage Regulator (LDO) testing:
                          http://www.badcaps.net/forum/showthr...999#post300999

                          Inverter testing using old CFL:
                          http://www.badcaps.net/forum/showthr...er+testing+cfl

                          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                          http://s807.photobucket.com/user/budm/library/

                          TV Factory reset codes listing:
                          http://www.badcaps.net/forum/showthread.php?t=24809

                          Comment


                            #14
                            Re: need replacement transistor

                            Originally posted by vinceroger69 View Post
                            A good video showing wave soldering
                            https://www.youtube.com/watch?v=Ap-HY7qP9zE
                            Thanks, I'll check that out next time I get to the library.

                            I have seen 2 different setups in operation, one at Spacelabs (a biomedical equipment mfgr.) in the early '80s, and another in the mid-80s at a dental xray equip. mfgr. - don't know when surface-mounted stuff came on the scene, but there wasn't any back then that I'm aware of.

                            Comment


                              #15
                              Re: need replacement transistor

                              Originally posted by stj View Post
                              put the old one on a tester to see if it's npn or pnp etc.
                              Kinda hard to do that, one of the legs is busted off flush - still possible to test the diode-junctions, though, it's a pnp.

                              Comment


                                #16
                                Re: need replacement transistor

                                Where I worked they were just starting to test running boards with smt parts thru the solder wave and trying out different glues. This was quite some time ago and smt parts were not widely used yet.

                                Comment


                                  #17
                                  Re: need replacement transistor

                                  you do wave-solder smd
                                  to do it you need 2 things.

                                  1: you need to glue the parts down - annoys the hell out of me when i need to replace them!
                                  2: on chips you need larger pads on the end the wave flows towards to catch the solder before it bridges anything.
                                  you often see an arrow on these boards indicating the direction of the wave.

                                  Comment


                                    #18
                                    Re: need replacement transistor

                                    Originally posted by stj View Post
                                    you do wave-solder smd
                                    to do it you need 2 things.

                                    1: you need to glue the parts down - annoys the hell out of me when i need to replace them!
                                    2: on chips you need larger pads on the end the wave flows towards to catch the solder before it bridges anything.
                                    you often see an arrow on these boards indicating the direction of the wave.
                                    Interesting! Thanks

                                    Comment


                                      #19
                                      Re: need replacement transistor

                                      Looking for a suitable replacement still - I found a similar tranny in a psu (guess I should have mentioned that the broken one is in either a to92-L or to92-MOD, but I didn't know at the time), here's a couple datasheets, the 2sb647 being the original and the ksa928a being similar (but is it similar enough?)

                                      Not sure anything attached, can't see it in the preview...

                                      Nope, couldn't load the links - anyway, does anyone know if these two transistors are close enough that I can use the ksa928a in place of the 2sb647?

                                      Thanks for any insight...
                                      Last edited by xelectech; 02-13-2016, 07:59 AM.

                                      Comment


                                        #20
                                        Re: need replacement transistor

                                        http://alltransistors.com/crsearch.p...e=60&caps=TO92


                                        Type Designator: 2SB647

                                        Material of transistor: Si

                                        Polarity: PNP

                                        Maximum collector power dissipation (Pc), W: 0.9

                                        Maximum collector-base voltage |Ucb|, V: 100

                                        Maximum collector-emitter voltage |Uce|, V: 80

                                        Maximum emitter-base voltage |Ueb|, V: 0

                                        Maximum collector current |Ic max|, A: 1

                                        Maksimalna temperatura (Tj), °C: 125

                                        Transition frequency (ft), MHz: 70

                                        Collector capacitance (Cc), pF:

                                        Forward current transfer ratio (hFE), min: 60

                                        ---------------------------------------------------------------------------------------

                                        Type Designator: KSA928A

                                        Material of transistor: Si

                                        Polarity: PNP

                                        Maximum collector power dissipation (Pc), W: 1

                                        Maximum collector-base voltage |Ucb|, V: 30

                                        Maximum collector-emitter voltage |Uce|, V: 30

                                        Maximum emitter-base voltage |Ueb|, V: 5

                                        Maximum collector current |Ic max|, A: 2

                                        Maksimalna temperatura (Tj), °C: 150

                                        Transition frequency (ft), MHz: 120

                                        Collector capacitance (Cc), pF: 48

                                        Forward current transfer ratio (hFE), min: 100

                                        Comment

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