LG 50PT250 Plasma - no picture

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  • rahulmadhukar
    Senior Member
    • Aug 2013
    • 51
    • Australia
    #1

    LG 50PT250 Plasma - no picture

    Hi Everyone,

    Starting a new thread to troubleshoot on a 50" plasma which is having no picture but sound. I tried to generate test patterns by shortening ext_auto on the control card but no video at all, which suggests that the mainboard is good. I checked the Vs and Va which appears to be good. When I switch the TV on in dark I see no light at all, does that mean the Z-main is faulty. Is there any way to confirm if the fault is in Z-Main/Y-main or power board. I cannot isolate bypass Y-main here as Z-main is connected via Y-main.

    The owner of the TV was telling this TV had starting problems earlier but slowly that aggravated and the TV is no more turning on. I suspected some fuses before buying it, but my bad luck.... Its's actually turning on pretty fine using remote. I can change the channels, etc but cannot see the picture. I have a multimeter, soldering iron, etc to troubleshoot further. Please suggest how to go ahead with this. Thanks. Rahul.
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    • Hamie
      Badcaps Legend
      • Apr 2014
      • 1383
      • UK
      #2
      Re: LG 50PT250 Plasma - no picture

      you should see 2 resistors on the y-sus that have vsc and -vy
      What are these voltages?

      Multimeter dc volts, red on positive black negative.

        Comment

        • rahulmadhukar
          Senior Member
          • Aug 2013
          • 51
          • Australia
          #3
          Re: LG 50PT250 Plasma - no picture

          Hi Hamie, Thanks for reply mate. Vsc= 142.7 and Vy=191.8. Also I checked Vs=205.1 and Va=55.0V, They both matches exactly same as per the panel data. Does that mean my Y-sus is good ? Is there anything I can do to check the Z-sus too? Please suggest how to localize the problem. Thanks.

            Comment

            • munirutech
              Senior Member
              • Oct 2013
              • 72
              • Ghana
              #4
              Re: LG 50PT250 Plasma - no picture

              your drives are up and down try to disconnect the upper one first and switch it on if is from the drive you will see only half screen if the same, try the down one and fix the upper one you remove and switch it on and see,sometimes if one of the ics on the drives is shorting can also cause this type of fault

                Comment

                • rahulmadhukar
                  Senior Member
                  • Aug 2013
                  • 51
                  • Australia
                  #5
                  Re: LG 50PT250 Plasma - no picture

                  Hi Munirutech, I tried removing the sub-buffers one at a time but no picture at all. When I try to switch on the TV in very dark room I don't see even a slight light on the screen, does that mean my Z-main is faulty ? Is there any method to check Z-main. Thanks.

                    Comment

                    • adnan hamod
                      New Member
                      • Oct 2018
                      • 1
                      • yeman
                      #6
                      Re: LG 50PT250 Plasma - no picture

                      شكراا

                        Comment

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