How to make LVDS test under 99 cents

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #21
    Re: How to make LVDS test under 99 cents

    "55' Samsung LED TV won't can on , unplug power cable to mother board , back light come on" That is one way of finding out if the power supply/backlights are OK or not, they (Samsung) installed the pull-up resistors (for ACTIVE HIGH) for the PS-ON and the BL-ON into the power supply board so the tech in the field does not have to rig up two external resistors to test the power supply and backlights circuit, save them time in the field. Samsung has done that more than 3 years ago.
    Last edited by budm; 04-20-2015, 06:50 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

    Comment

    • Peter Chiu
      Banned
      • Dec 2012
      • 145
      • USA

      #22
      Re: How to make LVDS test under 99 cents

      Emerson 32-37 CCLF TV did that to ,It is white flat cable near the ballast. unplug them screen light up, I think Sanyo did that too... really tough day on Monday, always.......see U

      Comment

      • Peter Chiu
        Banned
        • Dec 2012
        • 145
        • USA

        #23
        Re: How to make LVDS test under 99 cents

        still working on resistance to current converter circuit

        https://www.google.com/search?q=resi...ed=0CAYQ_AUoAQ

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #24
          Re: How to make LVDS test under 99 cents

          Which one are you trying to make the LVDS driver or the LVDS receiver?
          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

          • Peter Chiu
            Banned
            • Dec 2012
            • 145
            • USA

            #25
            Re: How to make LVDS test under 99 cents

            This one ( LVDS signal current detector).

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #26
              Re: How to make LVDS test under 99 cents

              You mean the receiver.
              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

              • Peter Chiu
                Banned
                • Dec 2012
                • 145
                • USA

                #27
                Re: How to make LVDS test under 99 cents

                An ESR meter: is measure the equivalent series resistance (ESR) of real capacitors.
                So I need a resistance to current converter circuit, to convert ESR meter to my LVDS current detector.

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #28
                  Re: How to make LVDS test under 99 cents

                  ESR is basically AC Ohm meter that forces high frequency current through the cap, the frequency has to be high enough so the Xc of the cap will not have an affect to the reading of the cap ESR.
                  You are trying to detect the LVDS signal generated by the main board so you need the receiver with 100 Ohm termination (you have 3.5mA of current from the Driver that force the current through 100 Ohms to produce 350mV of signal at the diff input of the diff amp). Since you have lot of T-CON board around, so you can use the receivers on the T-CON.
                  LVDS is just diff amp with 100 Ohm termination at the input, then you take the output to drive some kind of indicator circuit.
                  https://cdn.badcaps-static.com/pdfs/...8a1abbe8ae.pdf
                  Last edited by budm; 04-22-2015, 09:19 AM.
                  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

                  • Peter Chiu
                    Banned
                    • Dec 2012
                    • 145
                    • USA

                    #29
                    Re: How to make LVDS test under 99 cents

                    Good idea....I'll try it...and back to U.

                    Comment

                    • jarapunga
                      New Member
                      • Jan 2015
                      • 6
                      • Zimbabwe

                      #30
                      Re: How to make LVDS test under 99 cents

                      Hi there. I need to ask how to tell whether an LVDS cable is 6,8 or 10bit by just looking at it. Same goes for the whether it's 1 or 2 channels? What do you count, the twisted pairs? Sorry I realize this is an old post but I am tempted to ask anyway. Thanks. I am especially referring to LCD/LED TV LVDS cables.
                      Last edited by jarapunga; 02-12-2016, 03:45 AM.

                      Comment

                      • cferry7
                        New Member
                        • Apr 2016
                        • 1
                        • USA

                        #31
                        Re: How to make LVDS test under 99 cents

                        Hello Peter Chiu and budm.

                        Just wanted to let you know that I have enjoyed reading this thread and that I find it quite interesting !

                        I may have some questions for the both of you on a LCD Panel project that I may be attempting in the near future.

                        In appreciation.
                        Username : cferry7

                        Comment

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