Samsung 943b no power on after power off

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  • pfrcom
    Oldbie
    • Jun 2006
    • 1230
    • Australia
    #1

    Samsung 943b no power on after power off

    This is from a Samsung 943b which, after power off, will not power on unless switched off at the power point for a while

    Its controls are all touch sensitive, not mechanical

    Nothing obvious wrong to my eyes, nor anything gross when I try my ESR meter on the Sam Young electrolytics in situ

    Suggestions ?
    Attached Files
    better to keep quiet and be thought a fool, than to open your mouth and remove all doubt
    Tags: None
    • retiredcaps
      Badcaps Legend
      • Apr 2010
      • 9271
      #2
      Re: Samsung 943b no power on after power off

      Originally posted by pfrcom
      Suggestions ?
      1) Does the power LED come on?

      2) If not, are the secondary voltages and 5V present on the power and logic board?

      3) If present, do the voltage regulators output the correct voltage?

      4) Any cold or bad solder joints?
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        Comment

        • pfrcom
          Oldbie
          • Jun 2006
          • 1230
          • Australia
          #3
          Re: Samsung 943b no power on after power off

          The power LED does come on from a cold start

          But after power off, will not come back on

          Until left for a while switched off at the power point, after which it does come on and monitor works normally

          Not confident about voltage checking, was hoping for an obvious problem
          better to keep quiet and be thought a fool, than to open your mouth and remove all doubt

            Comment

            • retiredcaps
              Badcaps Legend
              • Apr 2010
              • 9271
              #4
              Re: Samsung 943b no power on after power off

              Originally posted by pfrcom
              Not confident about voltage checking, was hoping for an obvious problem
              Post pictures of your boards in this composition

              https://www.badcaps.net/forum/showpo...94&postcount=1

              and I can walk you through measuring the voltages on the secondary side. The voltages on the secondary side are likely to be 24V DC or less. If they are absent, then it will be necessary to measure the primary (HOT) side. If you have aligator clips, it will make measuring the hot side less intimidating as shown by budm in this thread (but we are not measuring for AC - only DC in your situation)

              https://www.badcaps.net/forum/showpo...1&postcount=13
              --- begin sig file ---

              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

              We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

              Please do not post inline and offsite as they slow down the loading of pages.

              --- end sig file ---

                Comment

                • selldoor
                  Slow Learner
                  • Dec 2010
                  • 7870
                  #5
                  Re: Samsung 943b no power on after power off

                  Service manual is here:

                  http://www.scribd.com/doc/56414365/S...Service-Manual
                  Please upload pictures using attachment function when ask for help on the repair
                  http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment

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