LG 42LC2D no picture

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  • bestjm
    Member
    • May 2017
    • 11
    • USA
    #1

    LG 42LC2D no picture

    I have an LG 42LC2D tv that recently lost picture. When I turn the unit on I get a click, the red standby light blinks green 12-14 times and then turns solid. When I press the power button, it takes several seconds to turn off. I have replaced several caps including one visibly blown one. The unit is still not working. I started disconnecting wiring harnesses. When I disconnect the 13 pin harness, the unit will power on correctly, but still no picture. With the set still on, I reconnected the harness and I have video. The pictures included have the harness I am talking about circled. Any ideas? Thanks in advance.
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    • dick_barton
      Badcaps Legend
      • Aug 2015
      • 6643
      • Wales
      #2
      Re: LG 42LC2D no picture

      So what DC voltages do you have on that harness when it is connected to the mainboard and you have no picture?
      Willing to help but I'm no expert.

        Comment

        • bestjm
          Member
          • May 2017
          • 11
          • USA
          #3
          Re: LG 42LC2D no picture

          I took these readings this afternoon. The second 5V pin was steadily dropping. When I first took the reading, it was showing almost 1.5v.

          AC DET - OL
          RL ON - 1.85v
          ST 5V - OL
          GND - 0
          INV ON/OFF - .012v
          5V MNT - .072 dropping
          POL/INV - 1.112v
          ST 5V - OL
          GND - 0
          PWM - .118v
          6.0 V - OL
          GND - 0
          LIVE ON - 1.476v

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA
              #4
              Re: LG 42LC2D no picture

              Originally posted by bestjm
              I took these readings this afternoon. The second 5V pin was steadily dropping. When I first took the reading, it was showing almost 1.5v.

              AC DET - OL
              RL ON - 1.85v
              ST 5V - OL
              GND - 0
              INV ON/OFF - .012v
              5V MNT - .072 dropping
              POL/INV - 1.112v
              ST 5V - OL
              GND - 0
              PWM - .118v
              6.0 V - OL
              GND - 0
              LIVE ON - 1.476v
              What is the meter DCV range set to, it should not be showing OL on ST5V for example. You need to retest those Voltages again, also need to look for the Inverter power supply Voltages.
              Right now you are saying you do not have pictures, which you will not see the pictures because the Blacklights are not on for you to be able to see the image on the screen because the main board is not sending the INVERTER ON (BL-ON) signal.
              Last edited by budm; 05-20-2017, 03:58 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

                • bestjm
                  Member
                  • May 2017
                  • 11
                  • USA
                  #5
                  Re: LG 42LC2D no picture

                  Sorry. I must have had the range too low.

                  AC DET - 0v
                  RL ON - 1.85v
                  ST 5V - 4.98v
                  GND - 0
                  INV ON/OFF - 0
                  5V MNT - .08v
                  POL/INV - 1.112v
                  ST 5V - 4.96v
                  GND - 0
                  PWM - .10v
                  6.0 V - 6.13v
                  GND - 0
                  LIVE ON - 1.476v

                  It looks like the inverter power supply voltages are all above 24v. Thanks for your help.
                  Last edited by bestjm; 05-20-2017, 08:10 PM.

                    Comment

                    • bestjm
                      Member
                      • May 2017
                      • 11
                      • USA
                      #6
                      Re: LG 42LC2D no picture

                      I'm still looking for help with this issue. If anyone has any advice I would appreciate it.

                        Comment

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