Unknow transistor

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  • jasko_jacker
    Badcaps Legend
    • Oct 2014
    • 1137
    • italy

    #1

    Unknow transistor

    It's marked as Q4 so I think is a transistor or something like this. Tester return unknow or damage component, what kind of transistor is ?
    It's possible it's a TI431 ?
    Last edited by jasko_jacker; 10-24-2019, 09:57 AM.
  • vinceroger69
    Badcaps Legend
    • Mar 2012
    • 6714
    • uk

    #2
    Re: Unknow transistor

    this?
    https://www.aliexpress.com/item/32422924466.html

    Comment

    • R_J
      Badcaps Legend
      • Jun 2012
      • 9532
      • Canada

      #3
      Re: Unknow transistor

      Is the component itself marked as Q4 or is that its designation on the board? Got a picture?

      Comment

      • mcplslg123
        Badcaps Legend
        • Jun 2015
        • 7262
        • india

        #4
        Re: Unknow transistor

        Which mobo?? Any code/laptop model??

        Comment

        • jasko_jacker
          Badcaps Legend
          • Oct 2014
          • 1137
          • italy

          #5
          Re: Unknow transistor

          sorry there was a photo upload error
          Attached Files

          Comment

          • vinceroger69
            Badcaps Legend
            • Mar 2012
            • 6714
            • uk

            #6
            Re: Unknow transistor

            my guess tl431

            Comment

            • KvnTM
              Badcaps Veteran
              • May 2018
              • 434
              • Germany

              #7
              Re: Unknow transistor

              Originally posted by vinceroger69
              my guess tl431
              Not quite sure. Take a look at the datasheet for sot23 markings. Search for PACKAGE OPTION ADDENDUM in the pdf.
              TL431 is a voltage reference and wouldnt be marked as "Q" on the board.

              OP: Try to get a schematic for that laptop. The circuit will tell you more.
              Attached Files
              Last edited by KvnTM; 10-25-2019, 05:20 AM.

              Comment

              • R_J
                Badcaps Legend
                • Jun 2012
                • 9532
                • Canada

                #8
                Re: Unknow transistor

                I would also say it's a tl431 reference ic, I suspect it it in the secondary of a smps near the optocoupler

                Comment

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