Problem looks like bulging cap, but none of them look bulging

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  • hubschman
    New Member
    • Nov 2012
    • 2
    • USA

    #1

    Problem looks like bulging cap, but none of them look bulging

    Hello, this is my first post to this forum. I couldn't find a previous post that addresses this issue, so apologies for wasting bandwidth if there is one. I also tried to post this earlier but it didn't seem to go through, so if it's there and I just don't see it, again sorry...

    So, I have 4 samsung syncmaster 930b monitors on 4 head system. In the last year, three of them started to exhibit symptoms of what I now understand is probably bad power supply capacitors: fast flashing green power button light when I turn on the monitor, and it takes a few minutes after booting until the monitor warms up and the light goes to slow blinking and an image appears. I've moved the monitors to different systems with the same behavior, so I'm confident the problem is inside the monitors.

    I found an excellent post that explains how to replace defective capacitors
    (Samsung 930b LCD cold start problem (inverter?) by gdement dated 09/05/08) with awesome pictures that I used to open one of the monitors to take a look. Unfortunately I can't see anything on the power supply capacitors - bulging, corrosion, discoloration - to indicate a defect.

    Before I buy a replacement kit and replace the capacitors, I'm wondering if the problem could still be a defective capacitor even if the capacitors look pristine. I looked only at the power supply, so perhaps there's a capacitor somewhere else that I didn't get to.

    I've had these monitors for six and a half years, during which time they've been on 12 to 15 hours per day, almost every day of the year. That's roughly 25,000 hours of operation per monitor. The three defective monitors started to fail in the last half year, one after another every few months. I've never experienced this before so it took a while before I realized theproblem is probably a bad power supply issue (which I finally figured out thanks to this forum!) I'm wondering if failures after 25,000 hours of operation so quickly one after the other sounds reasonable.

    Thanks in advance for any answers.

    hh
  • Pentium4
    CapXon Be Gone
    • Sep 2011
    • 3741
    • USA

    #2
    Re: Problem looks like bulging cap, but none of them look bulging

    That is quite a lot of running hours, especially since Samsung seem to love bad capacitor brands like CapXon and Samwha. Could you post some pictures of the internals?

    Comment

    • selldoor
      Slow Learner
      • Dec 2010
      • 7870

      #3
      Re: Problem looks like bulging cap, but none of them look bulging

      Yes check all 3 have the same insides and post pics. Caps most of the time seem to fail with no signs. In the thread you mention it lists the caps that were in their sets and if your are the same then use the same replacements. Some got away with changing the 1000uf 15v caps for 1000uf 25v. Pay particular attention to replies by Plainbill in the thread. Do not buy cap kits off ebay. Many are fakes.
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

      Comment

      • 999999999
        Badcaps Veteran
        • Sep 2006
        • 774
        • USA

        #4
        Re: Problem looks like bulging cap, but none of them look bulging

        Swap the power board from the working monitor into one of the others... one at a time, to see if they all work with it. If so, then you've narrowed the cause and can compare the working board with non-working.

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Problem looks like bulging cap, but none of them look bulging

          Does the inside look like this?
          http://s807.photobucket.com/albums/y...amsung%20930B/
          I would also replace the small start up caps (22~47uf 25~50vdc) in the primary side.
          With that many hours on the lamps, you can expect lamp failure soon also.
          http://s807.photobucket.com/albums/y...klight%20lamp/
          When you see it acting up, you can use hair dryer to heat up the caps (ESR goes down when temperature goes up) to see if it will start right away.
          Last edited by budm; 11-27-2012, 10:48 PM.
          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

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