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LG 60LN5400 Blows TCON Fuse

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    #1

    LG 60LN5400 Blows TCON Fuse

    I could have sworn I posted about this before, but I can't seem to find the post..

    To whit..

    I have a 60LN5400 that came in.. Backlights work fine.. No display..

    Traced the problem to the TCON board.. Blown fuse..

    Replaced the fuse.. Blows again.. Replaced the fuse again... This time it fries the marked part on the Main Video board...

    Got a new Main Video Board.. Replaced the fuse on the TCON..

    The fuse is fine and the backlights come on fine if I don't have the cellophane connectors from the TCON to the Panel..

    So, I am figuring that ONE of the panel boards are bad.. Try it with the left panel board disconnected, right panel board connected... Blows fuse..

    Try it with the left panel board connected and the right panel board disconnected.. Blows fuse.

    So far, the component on the Main Video Board is OK. Thank the gods for small favors..

    So, I am now guessing that there is a short on BOTH panel boards..

    So, my question is, is there any meter diagnostics I can try to track it down and/or is there anything I can do about it even if I CAN track it down??

    It's a nice TV... Would hate to trash it because of this if it can be fixed somehow..

    Any assistance would be most appreciated...

    NOTE: I did find this comment that has a similar issue

    https://www.badcaps.net/forum/showth...light=60ln5400

    But it's technical enough that I don't know if it's the same issue I am facing...
    Attached Files
    Tags: None
    #2
    Re: LG 60LN5400 Blows TCON Fuse

    If the t-con is located at the bottom of the tv, it is likely that someone cleaned the screen and the liquid ran down and damaged components on the board that connects the t-con to the actual lcd panel. This is the board that runs along the length of the panel at the bottom of the screen.
    Or it could be that one of the side driver ic's are are shorted.
    Last edited by R_J; 10-30-2019, 09:39 AM.

    Comment

      #3
      Re: LG 60LN5400 Blows TCON Fuse

      Yea, that's what I am thinking as well..

      I can pull the panel and look at those panel boards.. Hopefully it's something that can be cleaned off or repaired...

      Thanx for the reply..

      Comment

        #4
        Re: LG 60LN5400 Blows TCON Fuse

        Check the small ceramic caps on tcon for shorts, can use diode mode probe on each end if it beeps probably a short somewhere, if any beep unhook tcon from panel like you did one side at a time then both if needed and see if they still read bad.

        Comment

          #5
          Re: LG 60LN5400 Blows TCON Fuse

          Here are some pics of the LVDS Boards (???) attached to the panel..

          No obvious shorts or burns... I find it highly coincidental that BOTH boards will short the TCON fuse..

          Will check the small ceramic caps as suggested next..
          Attached Files

          Comment

            #6
            Re: LG 60LN5400 Blows TCON Fuse

            Originally posted by nomoresonys View Post
            Check the small ceramic caps on tcon for shorts, can use diode mode probe on each end if it beeps probably a short somewhere, if any beep unhook tcon from panel like you did one side at a time then both if needed and see if they still read bad.
            It occurred to me that maybe the LVDS Boards off the panel were shorting against the metal panel cover that protects those panel boards..

            No such luck.. I tried it without that metal shield and the TCON fuse still blew..

            OK, now just to confirm..

            The components marked in purple. Those are ceramic caps and put my meter in DIODE mode and if I get a short on the ends, that's bad??
            Attached Files

            Comment

              #7
              Re: LG 60LN5400 Blows TCON Fuse

              Can you check that the fault is located on the Tcon board or not by disconnecting all the cables to the Tcon and from Tcon to panel and measure the resistance from the Tcon fuse to ground and then start reconnecting them one by one checking each time.
              Last edited by dick_barton; 10-30-2019, 10:20 AM.
              Willing to help but I'm no expert.

              Comment

                #8
                Re: LG 60LN5400 Blows TCON Fuse

                Originally posted by Michale32086 View Post
                It occurred to me that maybe the LVDS Boards off the panel were shorting against the metal panel cover that protects those panel boards..

                No such luck.. I tried it without that metal shield and the TCON fuse still blew..

                OK, now just to confirm..

                The components marked in purple. Those are ceramic caps and put my meter in DIODE mode and if I get a short on the ends, that's bad??
                Yes, just a probe on each end, they're marked starting with C, white one is fuse that will beep, if any others beep probably a short somewhere.
                Last edited by nomoresonys; 10-30-2019, 10:28 AM.

                Comment

                  #9
                  Re: LG 60LN5400 Blows TCON Fuse

                  Originally posted by dick_barton View Post
                  Can you check that the fault is located on the Tcon board or not by disconnecting all the cables to the Tcon and from Tcon to panel and measure the resistance from the Tcon fuse to ground and then start reconnecting them one by one checking each time.
                  Will do.. Stand by..

                  Comment

                    #10
                    Re: LG 60LN5400 Blows TCON Fuse

                    OK with the TCON isolated and with the TCON hooked to the panel by both connectors, I get 3.9 to 4.16 ohms on the top part of the fuse to GND...

                    Comment

                      #11
                      Re: LG 60LN5400 Blows TCON Fuse

                      What is the supply voltage and fuse rating on the Tcon?
                      Willing to help but I'm no expert.

                      Comment

                        #12
                        Re: LG 60LN5400 Blows TCON Fuse

                        Originally posted by dick_barton View Post
                        What is the supply voltage and fuse rating on the Tcon?
                        Here,,,
                        Attached Files

                        Comment

                          #13
                          Re: LG 60LN5400 Blows TCON Fuse

                          If it's a 12V supply and a 3 Amp fuse then 4 ohms will result in 3 amp current flow which it right at the fuse maximum rating. Anything less than 4 ohms will result in the fuse blowing.
                          Do you have access to a variable DC power supply?
                          Last edited by dick_barton; 10-30-2019, 11:15 AM.
                          Willing to help but I'm no expert.

                          Comment

                            #14
                            Re: LG 60LN5400 Blows TCON Fuse

                            Originally posted by dick_barton View Post
                            If it's a 12V supply and a 3 Amp fuse then 4 ohms will result in 3 amp current flow which it right at the fuse maximum rating. Anything less than 4 ohms will result in the fuse blowing.
                            Do you have access to a variable DC power supply?
                            Unfortunately, I do not..

                            Well, I do have a couple universal laptop power adapters.. 15v - 24v.. And some 9v and 12v wall warts...

                            Comment

                              #15
                              Re: LG 60LN5400 Blows TCON Fuse

                              That's a pity. If you did you could have set the current trip to 3Amps and then raised the voltage towards 12V to power the Tcon.
                              Willing to help but I'm no expert.

                              Comment

                                #16
                                Re: LG 60LN5400 Blows TCON Fuse

                                You checked the little caps on the panel boards for shorts?

                                Comment

                                  #17
                                  Re: LG 60LN5400 Blows TCON Fuse

                                  Have you checked the ceramic capacitor next to the fuse ?

                                  Comment

                                    #18
                                    Re: LG 60LN5400 Blows TCON Fuse

                                    Sorry about the late reply.. Had to meet the wife for lunch.

                                    Originally posted by nomoresonys View Post
                                    Yes, just a probe on each end, they're marked starting with C, white one is fuse that will beep, if any others beep probably a short somewhere.
                                    With my meter in DIODE MODE, most of them show .457 .037 etc etc..

                                    But the one marked in blue and a couple smaller ones around it show .0L
                                    Attached Files

                                    Comment

                                      #19
                                      Re: LG 60LN5400 Blows TCON Fuse

                                      Originally posted by diif View Post
                                      Have you checked the ceramic capacitor next to the fuse ?
                                      The cap next to the fuse shows .078v

                                      Comment

                                        #20
                                        Re: LG 60LN5400 Blows TCON Fuse

                                        use Ohm mode for checking for shorts/low resistance reading, not diode mode.
                                        " .037" That looks bad to me.
                                        I do not understand why using Diode mode to look for shorted/low resistance component.
                                        Last edited by budm; 10-30-2019, 12:28 PM.
                                        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

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