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LG 50pk950 psu issue

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    #1

    LG 50pk950 psu issue

    Hey guys first subject thread for me here so please bear with me! I'm not super familiar with electronics, but I'm learning so here goes!

    I picked up an lG 50pk950 last week, pretty cheap not working thinking it would be a good project to undertake, I've read around the net trying to isolate the problem and I believe its the psu.

    If I turn it on after being unplugged for a while it'll power up but at most 20 seconds but then it clicks off and only click the relays when trying to turn on. Same 3 clicks when everything is disconnected except the ac to psu. I Have checked the 3 10 ohm ceramic resistors and they're fine, D304 is fine off the board, f302 is fine. Does ic301 always take out d304 and f302 when it goes??

    Caps all look fine (unsure how to test) all other ceramic resistors read fine.

    Anything else commonly go wrong on these boards?

    Thanks!
    Tags: None
    #2
    Re: LG 50pk950 psu issue

    Posting pictures of the back of your tv showing the boards with clear pictures may help you more with fixing your problem

    Comment

      #3
      Re: LG 50pk950 psu issue

      If the TV powers on occasionally its not IC301.

      It's more likely ic701.
      Use freeze spray on ic701 and see if it turns on.

      Comment

        #4
        Re: LG 50pk950 psu issue

        I wish I could put up photos, but since i slammed my phone in a car door unfortunately I'm cameraless!

        But the board is this one


        Freezing ic701 didn't change a thing :/ still the usual. Initial power up gets to no signal, then switches off and click click click...usually haveto wait atleast a day before it'll get as far as no signal again. Totally perplexed.

        Comment

          #5
          Re: LG 50pk950 psu issue

          Possible fault:
          All supply voltages will come up then die
          Intermittent going on and off and clicking
          will work for 20 mins then will go off and start clicking*


          If heating/cooling ic701 makes no difference*

          check R103,R104,R105,R106,R107,R108,R109,R110,R111,R112, R113

          hope this may help

          Comment

            #6
            Re: LG 50pk950 psu issue

            Originally posted by sordids999 View Post
            Possible fault:
            All supply voltages will come up then die
            Intermittent going on and off and clicking
            will work for 20 mins then will go off and start clicking*


            If heating/cooling ic701 makes no difference*

            check R103,R104,R105,R106,R107,R108,R109,R110,R111,R112, R113

            hope this may help
            None of them are dead, what are the values supposed to be?

            Comment

              #7
              Re: LG 50pk950 psu issue

              Maybe try some heat ?

              Comment

                #8
                Re: LG 50pk950 psu issue

                Originally posted by seraph View Post
                none of them are dead, what are the values supposed to be?
                r103,r104=240k
                r105,r106=150k
                r107=100k
                r108,r109,r110=680k
                r112=620k
                r113=560k

                Comment

                  #9
                  Re: LG 50pk950 psu issue

                  Originally posted by sordids999 View Post
                  r103,r104=240k
                  r105,r106=150k
                  r107=100k
                  r108,r109,r110=680k
                  r112=620k
                  r113=560k

                  r103; 215k
                  r104; 225k
                  r105; 145k
                  r106; 146k
                  r107; 99.8k
                  r108; 590k
                  r109; 530k
                  r110; 590k
                  r112; 551k
                  r112; 455k

                  Obviously some of these are looking a little low, likely to be causing an issue?

                  Comment

                    #10
                    Re: LG 50pk950 psu issue

                    Originally posted by seraph View Post
                    r103; 215k
                    r104; 225k
                    r105; 145k
                    r106; 146k
                    r107; 99.8k
                    r108; 590k
                    r109; 530k
                    r110; 590k
                    r112; 551k
                    r112; 455k

                    Obviously some of these are looking a little low, likely to be causing an issue?
                    Should replacing these solve the issue??

                    Comment

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