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LG 60PZ550 Plasma - No Sound, No Picture

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    LG 60PZ550 Plasma - No Sound, No Picture

    Hello,

    My LG plasma died out without warning the other night while my daughter was watching it. She wasn't standing very close to it at the time, but said she didn't hear anything unusual.

    I can turn it on and the power indicator (front panel) responds, the relay clicks once, but there is no sound or picture. I see no change in the screen at any point (no glow). With the rear cover off and the TV 'on', I see a diode (D1) on the Control board flashing two long, then two short, if that helps any. The Va & Vs test points on the Power board (to chassis ground) both look fine to me {Va:55 = 54.9v , Vs:201 = 201.6v}.

    Any advice on where to go from here? I've worked with some electronics in the past, but am new to TV's. I'm sure I can take whatever readings are needed, but might need clarification along the way.

    That being said, I have what is probably a silly question regarding checking the fuses on my boards. I am not familiar with the way these fuses are mounted to the board. How do you remove them? I'll attach a picture showing what I am seeing.

    Thank you.
    Attached Files

    #2
    Re: LG 60PZ550 Plasma - No Sound, No Picture

    Those fuses are soldered into the board, check them with your meter, should be close to 0 ohms

    Comment


      #3
      Re: LG 60PZ550 Plasma - No Sound, No Picture

      Ah, they don't make it easy eh?

      I checked all fuses I see and each was good.

      Comment


        #4
        Re: LG 60PZ550 Plasma - No Sound, No Picture

        So based on the behavior I am seeing, are there any suggestions on what I should check? Thanks.

        Comment


          #5
          Re: LG 60PZ550 Plasma - No Sound, No Picture

          Can you post a picture of the Y-sustain and Z-sustain boards?
          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 60PZ550 Plasma - No Sound, No Picture

            Sure. Here are some cell phone pics. If you want more detail, let me know and I'll post clearer ones. Thanks.
            Attached Files

            Comment


              #7
              Re: LG 60PZ550 Plasma - No Sound, No Picture

              OK, on the Y-sustain, there should be some points or components marked Vsc and -Vy, do you see these? They may look similar to the "Vzb" marking on the Z-sustain in the top right corner.
              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


                #8
                Re: LG 60PZ550 Plasma - No Sound, No Picture

                I see them.
                Attached Files

                Comment


                  #9
                  Re: LG 60PZ550 Plasma - No Sound, No Picture

                  OK, can you measure the voltages across those points?
                  Multimeter on DC 1000V, red on (+) marked, black on (-) marked.
                  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 60PZ550 Plasma - No Sound, No Picture

                    The readings on the Y-sustain look good: Vsc = 150.4v , Vy = -178.3v
                    {tag calls for 150v & 178v, respectively}

                    I didn't know if you wanted me to check the Vzb on the Z-sustain board, but I did and when the set powers on it will climb up to ~6v then slowly bleed down.

                    Comment


                      #11
                      Re: LG 60PZ550 Plasma - No Sound, No Picture

                      It looks like from your Vzb reading the Z-sustain is failed then.
                      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


                        #12
                        Re: LG 60PZ550 Plasma - No Sound, No Picture

                        Thank you for your help, Tom. It looks like we are getting somewhere. My next questions are:

                        1. Is the Vzb dependent on anything off the Z-sustain board that should be checked?

                        2. Is this something that can, with a little guidance, be traced further to the component level, or is it more practical to just replace the board?

                        If a board change is needed, any recommended sources?

                        Comment


                          #13
                          Re: LG 60PZ550 Plasma - No Sound, No Picture

                          I've ordered another Z-sus board. I'll report back with the results.

                          Comment


                            #14
                            Re: LG 60PZ550 Plasma - No Sound, No Picture

                            Sorry, I missed your previous post. Hope the swap fixes it. As for causes, I'd be thinking that there's a short on the Z-sustain dragging the Vzb down with it. Possibly the SUS-DN FET/IGBT shorted. Repairable, but will cost at least $20~$30 in parts plus time to diagnose.
                            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


                              #15
                              Re: LG 60PZ550 Plasma - No Sound, No Picture

                              Is there a viable test for LG plasma buffer boards?

                              Comment


                                #16
                                Re: LG 60PZ550 Plasma - No Sound, No Picture

                                Yes but only if you post in your own thread.
                                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


                                  #17
                                  Re: LG 60PZ550 Plasma - No Sound, No Picture

                                  I know that when ordering a replacement, I should look to get the same Rev #.

                                  When I was shopping around for a replacement Z-Sustain board, the EAX62076601 rev G boards were going for $50 and up. I came across one at indyoutletcenter.com for only $2, but it didn't show the revision. Since it was less than $10 delivered, I took a chance and ordered it. It just arrived and is Rev H whereas my original is Rev G. Do you think it's safe to try this one or is there a risk of damage and should just order the same rev board?

                                  Thanks.
                                  Last edited by southbound; 09-21-2013, 07:51 PM.

                                  Comment


                                    #18
                                    Re: LG 60PZ550 Plasma - No Sound, No Picture

                                    Do you notice any substantial layout or connector differences? How about a comparison photo?
                                    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


                                      #19
                                      Re: LG 60PZ550 Plasma - No Sound, No Picture

                                      No differences that I have picked up. Here are some comparison pics.
                                      Attached Files

                                      Comment


                                        #20
                                        Re: LG 60PZ550 Plasma - No Sound, No Picture

                                        That should work fine. If one of the inductors (copper coils) or large capacitors were missing, it might have been for a 42", for example, which would not work well. But it looks identical to me, so it's probably some minor revision like changing a component supplier to reduce costs.
                                        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

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