Should I worry about dark/burnt? spots on power board?

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  • bw1
    Senior Member
    • Sep 2010
    • 172

    #1

    Should I worry about dark/burnt? spots on power board?

    A 19" Soyo monitor came in today - won't power up. A couple of obvious caps are bad (don't have these particular values in stock right now, otherwise I'd probably just try them) but I'm wondering about what looks like heat damage on the board.

    Is this normal? I've seen it before, but not sure if this is just something that happens, or if I should question attempting a repair on this one. For the record, nothing else in the chassis or anything else under the hood had any sign of heat damage, if that's what this is.

    Pictures attached. Comments appreciated!
    Attached Files
  • sabre504
    Badcaps Veteran
    • May 2010
    • 449
    • United Kingdom

    #2
    Re: Should I worry about dark/burnt? spots on power board?

    Hi post a pic of the back of the board

    Comment

    • Dgtech
      E. Technician
      • Apr 2009
      • 1462
      • Steeler

      #3
      Re: Should I worry about dark/burnt? spots on power board?

      Once all four of those caps are changed, you should just power it up to see what happens. I wouldnt worry about the burn marks until that is done first. If it doesnt power up after the cap change then i'd look further.
      The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

      Comment

      • bw1
        Senior Member
        • Sep 2010
        • 172

        #4
        Re: Should I worry about dark/burnt? spots on power board?

        Thanks Dgtech, I was hoping to hear that response. If I had these caps in stock I would have just done it, but since it involves ordering, ordering extra to have more in stock, and waiting for arrival, I was just making sure it was worth it.

        I'll try to get a pic of the back of the board shortly if I can track down another camera. For all of the computer/tech stuff laying all over here, it's one of the hardest things to find when I need it.

        Comment

        • jetadm123
          Badcaps Legend
          • Feb 2010
          • 2169

          #5
          Re: Should I worry about dark/burnt? spots on power board?

          I'm almost willing to bet those scorch marks are caused by SMD mosfets on the underside of the board. Also, make sure you replace ALL 5 of the caps, not just the bloated ones.

          Comment

          • bw1
            Senior Member
            • Sep 2010
            • 172

            #6
            Re: Should I worry about dark/burnt? spots on power board?

            Here is a pic of the back side.
            Attached Files

            Comment

            • jetadm123
              Badcaps Legend
              • Feb 2010
              • 2169

              #7
              Re: Should I worry about dark/burnt? spots on power board?

              Nice photo! Yeah, it looks like the marks are caused by mosfets Q9 and Q10. If you looked up the data sheets, you'd see that they pass a lot of current, which is why they run hot.

              Comment

              • bw1
                Senior Member
                • Sep 2010
                • 172

                #8
                Re: Should I worry about dark/burnt? spots on power board?

                I'll replace the caps and check back here and post results. Thanks!

                Comment

                • bw1
                  Senior Member
                  • Sep 2010
                  • 172

                  #9
                  Re: Should I worry about dark/burnt? spots on power board?

                  Everything looks good - replaced all 5. I'll ignore the dark spots... unless there are more problems, anyway.

                  Thanks for the advice!

                  Comment

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