LG 32LN578V PS b/d issue

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  • notallbad
    Badcaps Legend
    • Oct 2012
    • 1190
    • UK

    #41
    Re: LG 32LN578V PS b/d issue

    Originally posted by diif
    I have 10, how many would you like ?
    I can't see you waiting 6 weeks, stuff is taking about 2 weeks currently. I have one delivery last week that took 7 days.

    Apologies for delay in responding but to update I replaced the 2 faulty leds and the tv is working again. I shall lower the backlight and brightness settings down to about 20 and see how long the repair lasts for.

    The kids will be well happy now -with this Smart TV in their room.

    Thanks so much again for the Led's.

    Comment

    • diif
      Badcaps Legend
      • Feb 2014
      • 6978
      • England

      #42
      Re: LG 32LN578V PS b/d issue

      You're welcome, glad they got it fixed. How close are they colour wise to the originals ?

      Comment

      • notallbad
        Badcaps Legend
        • Oct 2012
        • 1190
        • UK

        #43
        Re: LG 32LN578V PS b/d issue

        I am somewhat useless at differentiating colours but to me look ok compared to the originals however they are somewhat brighter than the originals which is noticeable by two bright spots on power up or blank screen ( this is after the tv has been re-assembled).

        I guess it is possible the older leds still on the tv have aged so are no longer as bright as they were new or the new replacements but its fine for our use.

        Would imagine anyone wanting to sell on the TV after repair would sensibly replace all LED's and if I were better at soldering smd components I would have too!

        Comment

        • menlopete
          New Member
          • Dec 2020
          • 7
          • Ireland

          #44
          Re: LG 32LN578V PS b/d issue

          New user here, so maybe I should be opening a new thread rather than replying here.

          There are a couple of threads on this model, with similar problems, which I have read.
          However, this is my first time troubleshooting an LED TV, so I'm a little lost.
          I got this TV free from someone who had this problem - namely sound is OK, but no picture.
          With a torch I can see the LG logo on powerup and there is sound when I plug in a HDMI source, so it can't be too bad, I thought.
          The guy who gave it to me had bought a replacement power board, but that behaves exactly the same way.
          So I metered the connector from the power bd to the main bd.
          Main voltages are OK. However there are three lines whose function I don't understand:
          pwr on 3.5vdc 6.4vac (I measured with the multimeter set to DC and AC)
          drv_on 3vdc 5.7vac
          pdim 1.1vdc 2.1vac
          I get no voltage out to the backlights.
          What next? Should I get voltage at the backlight connector even if disconnected? (I don't)
          Should I start looking for a new main board?

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #45
            Re: LG 32LN578V PS b/d issue

            Originally posted by menlopete
            New user here, so maybe I should be opening a new thread rather than replying here.

            There are a couple of threads on this model, with similar problems, which I have read.
            However, this is my first time troubleshooting an LED TV, so I'm a little lost.
            I got this TV free from someone who had this problem - namely sound is OK, but no picture.
            With a torch I can see the LG logo on powerup and there is sound when I plug in a HDMI source, so it can't be too bad, I thought.
            The guy who gave it to me had bought a replacement power board, but that behaves exactly the same way.
            So I metered the connector from the power bd to the main bd.
            Main voltages are OK. However there are three lines whose function I don't understand:
            pwr on 3.5vdc 6.4vac (I measured with the multimeter set to DC and AC)
            drv_on 3vdc 5.7vac
            pdim 1.1vdc 2.1vac
            I get no voltage out to the backlights.
            What next? Should I get voltage at the backlight connector even if disconnected? (I don't)
            Should I start looking for a new main board?
            Start a new thread with make, model, and symptom on the headline. Attach good clear pictures of the whole backside of the TV showing all the boards and good clear straight shots of the whole power supply board.
            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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