Jamo A-101 Sub Amp

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  • nissam72
    New Member
    • Jan 2015
    • 7
    • India

    #21
    Re: Jamo A-101 Sub Amp

    Good morning Dear,

    Finally after a long time I have removed glues from the PCB, but still having same problem, is it possible to replace PWM IC?

    Kind Regards,

    Nissam.
    Attached Files

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #22
      Re: Jamo A-101 Sub Amp

      So can you read the P/N as printed for that Gate driver IC U2?
      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

      • nissam72
        New Member
        • Jan 2015
        • 7
        • India

        #23
        Re: Jamo A-101 Sub Amp

        Originally posted by budm
        So can you read the P/N as printed for that Gate driver IC U2?
        There is no number..

        Comment

        • Agent24
          I see dead caps
          • Oct 2007
          • 4951
          • New Zealand

          #24
          Re: Jamo A-101 Sub Amp

          Don't you just love it when they do that?

          If you can draw up a schematic of what pins of the IC connect to what, maybe someone can figure out what it might be. They're probably using a fairly well-known part.
          "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
          -David VanHorn

          Comment

          • rievax_60
            Badcaps Veteran
            • May 2012
            • 897
            • australia

            #25
            Re: Jamo A-101 Sub Amp

            Originally posted by japlytic
            I have handled a Jamo SUB250 unit and it has a variation of an "old school" computer power supply circuit (self oscillating) - the A-101 should be of the same variant mentioned thereof.
            I just opened up a Jamo SUB250 also. I can confirm that the SMPS really is a self oscillating half bridge using a pair of IRF730 MOSFETs which were shorted.

            I sent Jamo a message via their Facebook page expressing my annoyance that their products are failing prematurely because of the yellow glue.

            Comment

            • rievax_60
              Badcaps Veteran
              • May 2012
              • 897
              • australia

              #26
              Re: Jamo A-101 Sub Amp

              Originally posted by nissam72
              Good morning Dear,

              Finally after a long time I have removed glues from the PCB, but still having same problem, is it possible to replace PWM IC?

              Kind Regards,

              Nissam.
              U2 looks like it has built in high/low side drive. It might be a type of control IC that is normally found in something like the inverter in a CCFL lamp.

              Comment

              • rievax_60
                Badcaps Veteran
                • May 2012
                • 897
                • australia

                #27
                Re: Jamo A-101 Sub Amp

                This looks right, https://cdn.badcaps-static.com/pdfs/...345f70bf55.pdf
                Last edited by rievax_60; 04-17-2015, 05:06 AM. Reason: corrected link

                Comment

                • Huub88
                  New Member
                  • May 2017
                  • 2
                  • Netherlands

                  #28
                  Re: Jamo A-101 Sub Amp

                  Hello everyone,

                  I'm new to this forum and I registered because of this thread. I have a jamo a101 sub that stopped working overnight. The standby circuit is powered as far as I can tell, it just won't switch on when I apply an audio signal. How is the sub amp supposed to come out of standby?

                  Thank in advance

                  Comment

                  • sreeraj m
                    New Member
                    • Jul 2018
                    • 1
                    • india

                    #29
                    Re: Jamo A-101 Sub Amp

                    I have a jamo a101 sub that stopped working.i need to know the MOSFETs details in frond of the 100V 470 uf cap side

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #30
                      Re: Jamo A-101 Sub Amp

                      Originally posted by sreeraj m
                      I have a jamo a101 sub that stopped working.i need to know the MOSFETs details in frond of the 100V 470 uf cap side
                      What is the P/N as printed on the body?
                      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

                      • tothta75
                        New Member
                        • Oct 2020
                        • 1
                        • Hungary

                        #31
                        Re: Jamo A-101 Sub Amp

                        Halo,

                        could anyone tell me please, what should I use to remove the discoloured glue?
                        (I am a REAL beginner in electronics. Never repaired anything :-) )

                        THX:
                        Tamás

                        Comment

                        • jesgatt
                          New Member
                          • Jan 2021
                          • 1
                          • Malta

                          #32
                          Re: Jamo A-101 Sub Amp

                          Originally posted by rievax_60
                          Hi, I know that this post is a bit old, but is this the part number for the PWM controller? I tried IR21531D (which is quite similar) but the IC seems to not provide any oscillations (Note: I changed the IRF740 to P10NK60, since they were shorted).

                          Thanks

                          Comment

                          • Jicisson
                            New Member
                            • Jul 2022
                            • 1
                            • France

                            #33
                            Re: Jamo A-101 Sub Amp

                            Bonjour,
                            Je suis dans le cas #2 ou les traces de coulures sont sur ma pcb. Il y a des traces de surchauffe au niveau des transistors, comme sur la photo.
                            Est-il possible d'avoir les valeurs des condensateurs et des transistors concernés ?
                            Merci de votre aide.
                            Jicisson
                            Attached Files

                            Comment

                            • Tannie
                              New Member
                              • Mar 2024
                              • 1
                              • Nederland

                              #34
                              Hi all,
                              Today I recieved a Jamo A101 subwoofer.
                              The problem was it did not work at all. The switched power supply did not start oscillating. After measuring I noticed the feedback optocoupler was not switching. After checking some caps I finally found a defective Schottky diode. This one was fully shorted.
                              See backside of PCB here below. I have marked de culpritt diode in red. It is a SS16 diode. After replacing it, the subwoofer works well again.
                              Click image for larger version

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