Weird 29" LG Flatron Problem

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  • GraphicMan
    Senior Member
    • Aug 2018
    • 124
    • Egypt

    #1

    Weird 29" LG Flatron Problem

    Hello guys

    to cut a long story short
    I got a used 29" LG crt tv but in mint condition
    it worked fine with a great picture for 7 month

    then it started to shut down by itself few times a day
    to power it on again I have to press the power button on the TV to off then wait few sec then back on and it works

    it stayed like that for about 10 days

    then one day I turned the receiver off as the usual the tv display "s-video" on a black screen then after 10min it goes to sleep mode
    but this time I was surprised with a loud electric shock sounds before it went to sleep when I turned my head to see the screen it was displaying some mixed colors and it went off, I also smelled some mild electronic burn smell

    I thought the tv failed completely this time but I was surprised that it did turn on but producing same very loud electric shock like sound, so i turned it off immediately

    when I opened it up I found the main biggest cap have a belly on top
    so I replaced it with exact number but the problem is the same

    can some1 tell me what is that? and is it fixable?

    Thanks
  • petehall347
    Badcaps Legend
    • Jan 2015
    • 4422
    • United Kingdom

    #2
    Re: Weird 29" LG Flatron Problem

    most things are fixable .. post some nice pictures of all the parts .

    Comment

    • R_J
      Badcaps Legend
      • Jun 2012
      • 9514
      • Canada

      #3
      Re: Weird 29" LG Flatron Problem

      I tried looking for information on "weird 29" and found nothing. Maybe you should try posting the model number at least?? and don't forget the pictures.
      And that large cap's plastic top can "dome" but the cap will usually be fine.
      Last edited by R_J; 08-07-2018, 09:30 PM.

      Comment

      • GraphicMan
        Senior Member
        • Aug 2018
        • 124
        • Egypt

        #4
        Re: Weird 29" LG Flatron Problem

        Sorry I forgot to post the photos
        here it is
        including the model #

        but what about that electric shock very high noise?does not say anything?
        also the sequence in which the case happened?

        I would really like to fix it, the TV set has a very good bright picture, so I am assuming it is has not been used that much

        and yes I think the cap was not the prob at all
        but I changed it because many said a domed cap + turning off by itself means a bad cap
        Attached Files

        Comment

        • dick_barton
          Badcaps Legend
          • Aug 2015
          • 6642
          • Wales

          #5
          Re: Weird 29" LG Flatron Problem

          Can you check out how close the schematic is to your set. The power supply may be similar. See page 34

          The set is so dusty it's difficult to see any components markings. Also if brushed out you may see where the electrical smell / burning was coming from.
          Attached Files
          Last edited by dick_barton; 08-08-2018, 10:44 AM.
          Willing to help but I'm no expert.

          Comment

          • R_J
            Badcaps Legend
            • Jun 2012
            • 9514
            • Canada

            #6
            Re: Weird 29" LG Flatron Problem

            I would check the board for poor solder connections, Check the connections on the high voltage transformer and any parts mounted to heatsinks
            Caps I would check/replace would be C809, C810, they fail often on other similar tv's
            Last edited by R_J; 08-08-2018, 11:06 AM.

            Comment

            • vinceroger69
              Badcaps Legend
              • Mar 2012
              • 6714
              • uk

              #7
              Re: Weird 29" LG Flatron Problem

              The loud electric shock noise you hear could be cracked casing/dampness etc on the line out put transformer or the lead from the transformer to the crt arcing out somewhere just be really careful as very high voltage when working on crt tvs even if been unplugged a few days you can still get a nasty shock been there done that got scar too prove it.

              Comment

              • GraphicMan
                Senior Member
                • Aug 2018
                • 124
                • Egypt

                #8
                Re: Weird 29" LG Flatron Problem

                Thank you all for your prompt reply's

                I am not an electric engineer, just general knowledge

                I was hoping to know if that defect is something known or popular

                but it is logic for me to know that 10 days of auto shut down is something that lead to that end?

                it looks like i has to be checked out by a professional?

                Comment

                • petehall347
                  Badcaps Legend
                  • Jan 2015
                  • 4422
                  • United Kingdom

                  #9
                  Re: Weird 29" LG Flatron Problem

                  most times i had faults with crt tv.s it was the H.O.T transistor or flyback transformer . or a diode .

                  Comment

                  • GraphicMan
                    Senior Member
                    • Aug 2018
                    • 124
                    • Egypt

                    #10
                    Re: Weird 29" LG Flatron Problem

                    Originally posted by petehall347
                    most times i had faults with crt tv.s it was the H.O.T transistor or flyback transformer . or a diode .
                    Thanks bro
                    is that something easy to replace or must use the same part from a similar model?

                    btw, since the screen produce random mixed colors, would replacing the WHOLE chassis with an exact one from another set fix this problem?

                    Comment

                    • vinceroger69
                      Badcaps Legend
                      • Mar 2012
                      • 6714
                      • uk

                      #11
                      Re: Weird 29" LG Flatron Problem

                      swapping the chassis should solve the issues as long as the replacement is working ok.

                      Comment

                      • GraphicMan
                        Senior Member
                        • Aug 2018
                        • 124
                        • Egypt

                        #12
                        Re: Weird 29" LG Flatron Problem

                        Originally posted by vinceroger69
                        swapping the chassis should solve the issues as long as the replacement is working ok.
                        Thanks Vince

                        Comment

                        • vinceroger69
                          Badcaps Legend
                          • Mar 2012
                          • 6714
                          • uk

                          #13
                          Re: Weird 29" LG Flatron Problem

                          just be careful high voltage could be stored when removing the anode cap from the tube have a read up on how too discharge them as it gives a nasty shock.

                          Comment

                          • GraphicMan
                            Senior Member
                            • Aug 2018
                            • 124
                            • Egypt

                            #14
                            Re: Weird 29" LG Flatron Problem

                            Originally posted by vinceroger69
                            just be careful high voltage could be stored when removing the anode cap from the tube have a read up on how too discharge them as it gives a nasty shock.
                            yes I know that, 20K+
                            however I have read in an article that that was in the past, all modern CRT TV have a resistor to absorb that stored energy when you turn it off

                            http://lowendmac.com/2007/the-truth-...-shock-danger/

                            anyways I dont think I will do that anyways, it is beyond my experience

                            I am still surprised that nobody have witness this failure type before!!
                            Last edited by GraphicMan; 08-09-2018, 09:47 PM.

                            Comment

                            • angelos
                              Badcaps Veteran
                              • Dec 2012
                              • 562
                              • South Africa

                              #15
                              Re: Weird 29" LG Flatron Problem

                              The arcing of EHT can definitely cause your TV to go into standby or even shut down. I bet there is a crack around the LOPT chimney or on the red EHT wire going to tube.
                              Getting another LOPT will be difficult but depending where the EHT leak is you might be able to insulate it with some kind of sealant. The best thing is to catch it in the act when it arcs. Just keep your body parts far away when running set.

                              Regards

                              Comment

                              • GraphicMan
                                Senior Member
                                • Aug 2018
                                • 124
                                • Egypt

                                #16
                                Re: Weird 29" LG Flatron Problem

                                Originally posted by angelos
                                The arcing of EHT can definitely cause your TV to go into standby or even shut down. I bet there is a crack around the LOPT chimney or on the red EHT wire going to tube.
                                Getting another LOPT will be difficult but depending where the EHT leak is you might be able to insulate it with some kind of sealant. The best thing is to catch it in the act when it arcs. Just keep your body parts far away when running set.

                                Regards
                                Bro can you please share some pics for the parts you want me to check?
                                I will then make some photos for my TV for the same parts and see if this is realty the problem

                                thank you

                                Comment

                                • R_J
                                  Badcaps Legend
                                  • Jun 2012
                                  • 9514
                                  • Canada

                                  #17
                                  Re: Weird 29" LG Flatron Problem

                                  You say it is making a very loud electric shock like sound where is the sound coming from? Is it coming from the high voltage transformer?
                                  Is it a high pitched squealing sound or is it a loud snap... snap type sound?

                                  If it is high voltage that is arcing, check it in a darken room, you should be able to see the arcing.
                                  Last edited by R_J; 08-10-2018, 07:57 PM.

                                  Comment

                                  • GraphicMan
                                    Senior Member
                                    • Aug 2018
                                    • 124
                                    • Egypt

                                    #18
                                    Re: Weird 29" LG Flatron Problem

                                    Originally posted by R_J
                                    You say it is making a very loud electric shock like sound where is the sound coming from? Is it coming from the high voltage transformer?
                                    Is it a high pitched squealing sound or is it a loud snap... snap type sound?

                                    If it is high voltage that is arcing, check it in a darken room, you should be able to see the arcing.
                                    It is hard to know where the sound is coming from because it is very loud and I shut down the tv quickly because it seem so wrong

                                    it is not high pitched sound, I will try to video record that the next time
                                    I have not tried to turn it on with its cover open, but from many of the replies it seems like I have to remove all the inside dust first in order to see if there is any cracks around any component and to check for poor old solders as well
                                    if I did not see anything that seem wrong I will then turn it on and see if there is any visible arcing!
                                    I have not done anything like this before, I am also sure that this set have never been opened or serviced before

                                    Comment

                                    • GraphicMan
                                      Senior Member
                                      • Aug 2018
                                      • 124
                                      • Egypt

                                      #19
                                      Re: Weird 29" LG Flatron Problem

                                      I think it is clear now
                                      I have already recorded a video but for ease i am uploading this screenshots of it

                                      the sound is much less without the cover, seems like the cover was scaling it a lot

                                      the arcing is coming out from the flyback transformer as few members said (many thanks to them)

                                      I have also uploaded a clear pic for it, I cant see any cracks, it look so new!

                                      what do you think guys?!
                                      Attached Files

                                      Comment

                                      • petehall347
                                        Badcaps Legend
                                        • Jan 2015
                                        • 4422
                                        • United Kingdom

                                        #20
                                        Re: Weird 29" LG Flatron Problem

                                        that is cracked or lost its insulation .. new fly-back will likely be expensive if you can even find one .. i used to scrap sets with bad fly-back transformers as they simply wasn't worth spending that sort of money on .
                                        you may get lucky and find a new one cheap enough .

                                        Comment

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