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LG 42LV5500 solarization? - t-con, mainboard or panel?

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    #1

    LG 42LV5500 solarization? - t-con, mainboard or panel?

    Hi,

    I have an LG 42LV5500-UA.AUSDLUR with panel T420HW08 and an AU Optronics T-Con T315HW07 V9 31T14-COA (55.42T13.C06)

    I thought that the tv fault was the gamma ic on the t-con board since the symptoms look like the solarization fault. There are some fine vertical lines to the left of the images and the colors are messed up.
    I ordered another t-con board with exactly the same numbers as above and upon installation the fault looked exactly the same. The board was purchased from a reputable supplier of boards (not Ebay). When I contacted them about a return they offered to send out another t-con but did not have it in stock.
    I returned the board.
    If you look at photo of the t-con board I think that the gamma ic is on the upper left near the mounting screw - sorry, I know the pic isn't very sharp.
    I believe that the gamma ic is AUO-G1422 and it's a qfn package.
    The voltages on the original board (forgot to measure the replacement) are as follows.
    VGA1-15.08
    VGA2-14.61
    VGA3-12.53
    VGA4-10.88
    VGA5-9.94
    VGA6-8.51
    VGA7-8.46
    VGA8-7.72
    VGA9-7.68
    VGA10-5.24
    VGA11-4.29
    VGA12-2.89
    VGA13-.72
    VGA14-.31

    So the question is do you think that the t-con is bad or is it a bad panel or main board?
    Has anyone seen this issue with this model of LG set or this panel?
    I eagerly await expert opinions.
    Sorry for the flash on some of the photos.

    Thanks,
    Mike
    Attached Files
    Tags: None
    #2
    Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

    Hi,

    Doesn't anyone have any insight into this problem?
    Do the gamma voltages seem ok even though a couple of points are low?
    Could this be the result of a bad software update? The set has the most current firmware available from LG, but I was thinking about trying to downgrade to the previous version. I had a Samsung set once that changed a service menu setting upon upgrade and screwed up the picture. Fortunately, I was able find the solution online and changed the setting.
    Is is possible to get into the LG service menu without their special remote?
    I found some methods online but haven't tried them.

    Thanks,
    Mike

    Comment

      #3
      Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

      If you stick the values into Tom's T-con check sheet here https://www.badcaps.net/forum/showth...ighlight=gamma then the gamma voltages do look off.

      Comment

        #4
        Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

        VGA6-8.51
        VGA7-8.46

        VGA8-7.72
        VGA9-7.68

        These 4 do not look right, barely difference between each pair.
        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

          #5
          Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

          This level of solarisation is likely to be a main board issue more than anything else.
          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

            #6
            Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

            I didn't think that the main board could cause that kind of fault. Any solarization faults I've seen have been t-con related.
            Tom, if it is a main board problem that would certainly explain why the symptom didn't change with a replacement t-con.
            I welcome all the opinions and wish I would have taken gamma voltages on the replacement board I purchased before sending it back.
            Keep in mind that I think the gamma IC is the AUO-G1422 and not the AS-15F that usually fails.
            Do we think that the curves are valid for that chip as well?

            Mike

            Comment

              #7
              Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

              i wonder if its worth heating the mainboard up to see if it makes things better or worse maybe a bga issue? there are some updates on the lg site not sure what there for though
              http://www.lg.com/us/support-product/lg-42LV5500

              Comment

                #8
                Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

                Hi,

                I took another picture today of the main menu on the LG.
                The solarization isn't really evident but the lines to the left of the images are more clearly shown.
                I upgraded to the most current version of firmware available on the LG website and the symptom is the same. When I checked the firmware previously online it told me the version was the most recent.
                Does the new photo provide help decipher the problem?

                Thanks,
                Mike
                Attached Files

                Comment

                  #9
                  Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

                  Definitely a main board fault.
                  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

                    #10
                    Re: LG 42LV5500 solarization? - t-con, mainboard or panel? - Fixed!!

                    Thanks to all that replied.

                    I took a chance and baked the main board last night at 385 F for 10 minutes in my oven.
                    After letting it cool to room temperature with the oven door open - I reinstalled the main board.
                    I watched game 2 of the World Series last night! Picture looked very good.

                    Looks like it was a solder issue - the original t-con board is still in the set.
                    Still have to check the hdmi inputs, etc.
                    Hope it lasts.

                    Mike

                    Comment

                      #11
                      Re: LG 42LV5500 solarization? - t-con, mainboard or panel? - Fixed!!

                      I took a chance and baked the main board last night at 385 F for 10 minutes in my oven.
                      this process that is spruked on youtube does not work ,dont know why people keep doing this ,sorry to say this will not last ,your best bet is to replace the main board

                      Comment

                        #12
                        Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

                        Chris,

                        The reason that I took the chance was that I could not find the main board anywhere. The only possible choice was a board from Israel that made the repair uneconomical.
                        There are several different main boards for this set.
                        I am skeptical about things I see on the internet and frankly did not expect the results that I got.
                        Baking in the oven did verify that the fault was indeed on the mainboard and not the t-con or panel.
                        Will it last? Only time will tell.
                        I just wanted to post my results to give closure to the thread.
                        I would never resell this set based on this kind of fix.

                        Mike

                        Comment

                          #13
                          Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

                          Hey and now you have seen a Mainboard cause solarization which now you know can cause this issue in future cases. Nice fix btw
                          Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

                          https://www.facebook.com/Telford-Tel...7894576335359/

                          Comment

                            #14
                            Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

                            mike .....all is good ,hope it lasts
                            applying liquid soldering paste all over and through the BGA and heating the chip could be a solution
                            but great fix

                            Comment

                              #15
                              Re: LG 42LV5500 solarization? - t-con, mainboard or panel?

                              Originally posted by tom66 View Post
                              Definitely a main board fault.
                              Tom66, you deserve the applause!!!

                              Comment

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