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    Milk in TV - strange colors

    I obtained this TV with the info that the owner's little daughter has been supposedly painting the TV with milk It's an LG 32LW570S.

    I have been reported there was something with the ribbon cables but I have not found any residue or problem at any conenctor or cable, they are all clean, maybe cleaned by the owner, not sure. I can clean them with alcohol but don't think this is the right path. Anyway, the TV shows this

    instead of

    It seems to me as usuall voltage-buffer problem? This is the Tcon (not my image)

    There seem to be two chips, both SMD so the milk could have been sucked between the solder balls as the tiny space there behaves like capilary. They are TPS65194 and BUF08630.

    voltage readings at pins:
    GMA1: 16,67
    GMA3: 14,72
    GMA4: 13,90
    GMA5: 12,74
    GMA7: 10,68
    GMA9: 8,58
    GMA10: 0,50
    GMA12: 6,13
    GMA14: 4,03
    GMA15: 2,92
    GMA16: 2,17
    GMA18: 0,34
    H_CONV: 0,01
    POL: 1,66

    I would say channel 10 is the problematic one?
    Attached Files
    Last edited by Behemot; 08-21-2014, 02:15 PM.
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    #2
    Re: Milk in TV - strange colors

    "GMA10: 0,50"
    "I would say channel 10 is the problematic one?"
    Yes.
    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


      #3
      Re: Milk in TV - strange colors

      And the bad chip would be the TPS65194 one, right? I am just afraid if it could not be any problem in the ribbon board (there is PCB where the ribbons are soldered/glued), in the way it would be shorting this channel. In the case of AS15F it always helped on the other hand there was no milk
      Last edited by Behemot; 08-21-2014, 03:33 PM.
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        #4
        Re: Milk in TV - strange colors

        Did you check the bottom of the screen for residue? If the t-con is at the bottom on this tv the milk may be on the circuit board that connects the panel to the t-con.

        Comment


          #5
          Re: Milk in TV - strange colors

          Yeah I have checked that right away, found nothing from the signal board through Tcon to that panel board. I'll ask the owner today if he has actualy cleaned anything inside…
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            #6
            Re: Milk in TV - strange colors

            This is the part where the milk was

            SMD components seem fine. The dark spots on the golden joints were probably burned or oxidized or something. The paths were opened, I have tried to connect them like this but there was no change. They do not seem to be connected anywhere beyond the SMD joints (= dead end) so probably does not matter if they are opened.

            One thing though, if I disconnect the ribbons, some voltages dissapear from the test pads. Seem to me some signals go through one ribbon to one display PCB, than through the LCD to second PCB and back to the other ribbon. So there still may be some problem in between, but well, everything seems fine, if the display itself is bad internally, I won't know before the gamma chip is replaced anyway so I will just go for it.
            Attached Files
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            Comment


              #7
              Re: Milk in TV - strange colors

              Originally posted by Behemot View Post
              I obtained this TV with the info that the owner's little daughter has been supposedly painting the TV with milk It's an LG 32LW570S.

              I have been reported there was something with the ribbon cables but I have not found any residue or problem at any conenctor or cable, they are all clean, maybe cleaned by the owner, not sure. I can clean them with alcohol but don't think this is the right path. Anyway, the TV shows this

              instead of

              It seems to me as usuall voltage-buffer problem? This is the Tcon (not my image)

              There seem to be two chips, both SMD so the milk could have been sucked between the solder balls as the tiny space there behaves like capilary. They are TPS65194 and BUF08630.

              voltage readings at pins:
              GMA1: 16,67
              GMA3: 14,72
              GMA4: 13,90
              GMA5: 12,74
              GMA7: 10,68
              GMA9: 8,58
              GMA10: 0,50
              GMA12: 6,13
              GMA14: 4,03
              GMA15: 2,92
              GMA16: 2,17
              GMA18: 0,34
              H_CONV: 0,01
              POL: 1,66

              I would say channel 10 is the problematic one?
              id leave it as it is,that picture looks amazing!!
              fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

              ----------------------------------------------
              please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!

              Comment


                #8
                Re: Milk in TV - strange colors

                orly Well the customers thinks otherwise…
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                  #9
                  Re: Milk in TV - strange colors

                  Originally posted by Behemot View Post
                  This is the part where the milk was

                  SMD components seem fine. The dark spots on the golden joints were probably burned or oxidized or something. The paths were opened, I have tried to connect them like this but there was no change. They do not seem to be connected anywhere beyond the SMD joints (= dead end) so probably does not matter if they are opened.

                  One thing though, if I disconnect the ribbons, some voltages dissapear from the test pads. Seem to me some signals go through one ribbon to one display PCB, than through the LCD to second PCB and back to the other ribbon. So there still may be some problem in between, but well, everything seems fine, if the display itself is bad internally, I won't know before the gamma chip is replaced anyway so I will just go for it.
                  You know what worries me, the first 6 to 7 contacts of the ribbon cable on the left, they look to be tarnished, get some contact cleaner and spray a little in that area and then press on it while the Tv is on, see if it makes a difference.

                  Comment


                    #10
                    Re: Milk in TV - strange colors

                    I've tried pressing the contacts as very first thing, even before I noticed this area. Tried all of the flexes, there was no change at all no matter what I did with them…

                    I have checked once again just to be sure, that was probably just something on the top of the ribbon, not under that - as I have been cleaning it, I can see nothing out of the ordinary now.

                    What do those long chips (silicon wafers without any cover) soldered directly on those LCD ribbon cables do? All of them are pretty hot.
                    Last edited by Behemot; 08-22-2014, 06:22 AM.
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                      #11
                      Re: Milk in TV - strange colors

                      Still not sure whether to get TPS65194, BUF08630 or both. The latter is 8+1channel gamma voltage generator, the former is 13channel level shifter. I guess either one can be bad?
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                        #12
                        Re: Milk in TV - strange colors

                        Originally posted by Behemot View Post
                        What do those long chips (silicon wafers without any cover) soldered directly on those LCD ribbon cables do? All of them are pretty hot.
                        They are the source drivers. 10 bit DAC 0-15V output, approx 5,000 total channels (around 1,000~2,500 per IC typical.) They are responsible for image data on the panel.
                        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                        Comment


                          #13
                          Re: Milk in TV - strange colors

                          So which IC should I get? Both?
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                            #14
                            Re: Milk in TV - strange colors

                            Up?
                            Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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                              #15
                              Re: Milk in TV - strange colors

                              I don't have any idea which to get, maybe the only option is to replace T-con board.
                              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                              Comment


                                #16
                                Re: Milk in TV - strange colors

                                I have worked on a LG which had missing voltages, in two or three places and by replacing the IC on the T-con and one more time getting another T-Con board, did not fix the problem(did not have picture at all). Then I have checked the LCD panel itself, and I have found partially lifted ribbon, on the panel PCB.
                                I think, that those first 6-7 tracks from the ribbon cable, are actually lifted.
                                Somewhere I have read, that with some kind of T tip solder iron, which has some Teflon coating or similar material, can be heated up and it should glue back to the PCB.
                                Anybody knows anything about this procedure?
                                Last edited by tibimakai; 09-02-2014, 01:47 PM.

                                Comment


                                  #17
                                  Re: Milk in TV - strange colors

                                  But than pressing it would help, no?
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                                    #18
                                    Re: Milk in TV - strange colors

                                    Unfortunatelly even after swapping both ICs problem persists.
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