LG 50PZ550-UA Plasma has no picture or sound

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  • sredlin
    Member
    • Feb 2017
    • 10
    • USA

    #1

    LG 50PZ550-UA Plasma has no picture or sound

    I need help trying to diagnose which board might be bad on my LG Plasma 50PZ550-UA TV. I can turn it on and see a faint glow on the screen, but no picture or sound, and the only button that works is the on-off switch, I can press the other buttons like menu and volume control and the red LED on the front panel will blink to indicate that the button was pressed, but nothing happens on the screen. I've already removed the back and checked all power supply board output voltages and they are all there on the correct pins on all output connectors, so I'm confident that the problem is not the power supply.

    I've visually inspected all other circuit boards in an attempt to locate any obvious problems like blown out or puffed up caps, ICs or transistors with holes or burn marks, etc, and I did not find anything that's obviously bad. I now need to try to figure out which board/s might be causing my problem, and I'm not quite sure how to proceed with doing this, so any help here would be greatly appreciated, thanks.

    Scott
  • Hamie
    Badcaps Legend
    • Apr 2014
    • 1383
    • UK

    #2
    Re: LG 50PZ550-UA Plasma has no picture or sound

    Run test patterns on the control board. loads of threads showing how to do this.

    if you get test patterns you have a bad mainboard.

    Comment

    • ReeceyBurger123
      Never Give Up !
      • May 2014
      • 7325
      • Britain

      #3
      Re: LG 50PZ550-UA Plasma has no picture or sound

      Originally posted by hamie
      run test patterns on the control board. Loads of threads showing how to do this.

      If you get test patterns you have a bad mainboard.
      +1
      Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

      https://www.facebook.com/Telford-Tel...7894576335359/

      Comment

      • sredlin
        Member
        • Feb 2017
        • 10
        • USA

        #4
        Re: LG 50PZ550-UA Plasma has no picture or sound

        Originally posted by Hamie
        Run test patterns on the control board. loads of threads showing how to do this.

        if you get test patterns you have a bad mainboard.
        Thanks so much for the tip, I did see some threads about doing this, unfortunately I do not know how to do this? Most threads I found that talk about this describe a location to place a jumper wire to bring up the test patterns, and I am not sure where or even if my TV has such a location to place a jumper? I've carefully looked over all the boards several times trying to find a test pattern jumper, but I just don't know where it could be?

        I have tried disconnecting the Y-Sus and the Z-Sus boards to see if anything changes. And disconnecting the Y-Sus causes the faint screen glow to go away, but still no sound, and disconnecting the Z-Sus, results in some very faintly visible snow on the screen, and again no sound. And all my power supply voltages are present on the correct output pins, so I feel like it's probably the main board, but I'm not completely sure?

        Comment

        • ReeceyBurger123
          Never Give Up !
          • May 2014
          • 7325
          • Britain

          #5
          Re: LG 50PZ550-UA Plasma has no picture or sound

          I dont know how you cant find the threads google also provides loads of info, also yes your mainboard is bad very common on these.
          Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

          https://www.facebook.com/Telford-Tel...7894576335359/

          Comment

          • sredlin
            Member
            • Feb 2017
            • 10
            • USA

            #6
            Re: LG 50PZ550-UA Plasma has no picture or sound

            Originally posted by ReeceyBurger123
            I dont know how you cant find the threads google also provides loads of info, also yes your mainboard is bad very common on these.
            I did find a few different threads about test patterns and placing a jumper wire to view them, but I didn't find any that were specific to my TV model to provide the information I need to try to display test patterns. And there's no obvious jumper location on the circuit boards I have on my TV that's all.

            I guess I'll try and find a main board to swap into it and hopefully it fixes it?

            Comment

            • ReeceyBurger123
              Never Give Up !
              • May 2014
              • 7325
              • Britain

              #7
              Re: LG 50PZ550-UA Plasma has no picture or sound

              Give it a blast and keep us updated
              Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

              https://www.facebook.com/Telford-Tel...7894576335359/

              Comment

              • Hamie
                Badcaps Legend
                • Apr 2014
                • 1383
                • UK

                #8
                Re: LG 50PZ550-UA Plasma has no picture or sound

                So maybe a better idea would be to upload a picture of your control board before buying parts you might not need?

                Just a though!

                Comment

                • sredlin
                  Member
                  • Feb 2017
                  • 10
                  • USA

                  #9
                  Re: LG 50PZ550-UA Plasma has no picture or sound

                  Originally posted by Hamie
                  So maybe a better idea would be to upload a picture of your control board before buying parts you might not need?

                  Just a though!
                  Okay, the first picture is the logic control board, followed by the main board, and then the whole set of boards.
                  Attached Files

                  Comment

                  • dick_barton
                    Badcaps Legend
                    • Aug 2015
                    • 6642
                    • Wales

                    #10
                    Re: LG 50PZ550-UA Plasma has no picture or sound

                    Short the two holes next to R51 & R52 with a paper clip or piece of wire. Unclip and remove ribbon cable A:325, power up and check if you have patterns on the screen.
                    Willing to help but I'm no expert.

                    Comment

                    • Hamie
                      Badcaps Legend
                      • Apr 2014
                      • 1383
                      • UK

                      #11
                      Re: LG 50PZ550-UA Plasma has no picture or sound

                      +1

                      Comment

                      • ReeceyBurger123
                        Never Give Up !
                        • May 2014
                        • 7325
                        • Britain

                        #12
                        Re: LG 50PZ550-UA Plasma has no picture or sound

                        Tbh I think the search feature here is a little fucked one day it brings loads of results the next it doesnt. Also follow what DB says the Lvds must be disconnected when you do this or the screen will remain primed but blank.
                        Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

                        https://www.facebook.com/Telford-Tel...7894576335359/

                        Comment

                        • sredlin
                          Member
                          • Feb 2017
                          • 10
                          • USA

                          #13
                          Re: LG 50PZ550-UA Plasma has no picture or sound

                          Thanks all for your assistance with this, I will give it a try tonight or tomorrow, I'm at work at the moment so I can't try it right now, but I'll let you know what happens. Thanks again for your help.

                          Scott

                          Comment

                          • sredlin
                            Member
                            • Feb 2017
                            • 10
                            • USA

                            #14
                            Re: LG 50PZ550-UA Plasma has no picture or sound

                            Originally posted by dick_barton
                            Short the two holes next to R51 & R52 with a paper clip or piece of wire. Unclip and remove ribbon cable A:325, power up and check if you have patterns on the screen.
                            I finally got around to doing this test, and it works, I have the test patterns on the screen, solid red, solid green, solid blue, then gray, followed by a series of sweeps across vertically and horizontally. So I'm going to try to find a main board to order for it.

                            I found one on ebay that has a slightly different part number, and have asked the seller if he knows if the part number he has for a 60" plasma, EBT61533403 is compatible with the board I have, part number EBT61533103, maybe you or someone else on this thread would know? Both the ebay board and my board have an additional part number that matches completely, the number is: EBR73043303. So I'm thinking that maybe they are compatible, but I just don't know for sure, the look the same in the pictures?

                            Here's the ebay listing if anyone wants to see it:

                            http://www.ebay.com/itm/-/232254340715?

                            Comment

                            • Hamie
                              Badcaps Legend
                              • Apr 2014
                              • 1383
                              • UK

                              #15
                              Re: LG 50PZ550-UA Plasma has no picture or sound

                              Try reflowing the BGA under the heatsink.
                              If that fixes the fault you could consider taking the board to a TV/console/pc repair shop and ask them to reball it.

                              Should work out cheaper than the replacment part.

                              However if you give it a good reflow it can last for a decent amount of time anyway.

                              £80+ for a replacement second hand plasma part is criminal.

                              Comment

                              • sredlin
                                Member
                                • Feb 2017
                                • 10
                                • USA

                                #16
                                Re: LG 50PZ550-UA Plasma has no picture or sound

                                Originally posted by Hamie
                                Try reflowing the BGA under the heatsink.
                                If that fixes the fault you could consider taking the board to a TV/console/pc repair shop and ask them to reball it.

                                Should work out cheaper than the replacment part.

                                However if you give it a good reflow it can last for a decent amount of time anyway.

                                £80+ for a replacement second hand plasma part is criminal.
                                I will remove the board and have a look, but I'm not sure I have the solder skills for doing a re-flow on something like that? Although there may be something to that, since I can't see anything obviously fried on the board as it's mounted. And I did run across several internet postings on youtube and other places about putting main boards in the oven to make them start working, but I'm a little leary about trying that?

                                And I agree the cost for "a replacement second hand board is criminal", but there just doesn't seem to be any other options for this particular TV. I guess this TV is just too old for LG to continue to make and sell parts for it now?

                                Thanks for the advice, I'll let you know if I try it.

                                Scott

                                Comment

                                • sredlin
                                  Member
                                  • Feb 2017
                                  • 10
                                  • USA

                                  #17
                                  Re: LG 50PZ550-UA Plasma has no picture or sound

                                  I fixed it, probably by, "reflowing the BGA under the heatsink...", as suggested by Hamie. The process I used to accomplish this, is shown in the following youtube video, with about 2 minutes of heat gun on each side of the board. I was pretty surprised that it worked, but it did amazingly enough. Thank you all for the help with troubleshooting, I'm really happy that I don't have to spend money to fix this right now.

                                  https://www.youtube.com/watch?v=8sslythR5HE

                                  Comment

                                  • sredlin
                                    Member
                                    • Feb 2017
                                    • 10
                                    • USA

                                    #18
                                    Re: LG 50PZ550-UA Plasma has no picture or sound

                                    Forgot to attach the proof of concept photo.
                                    Attached Files

                                    Comment

                                    • tmxmnz
                                      New Member
                                      • Mar 2017
                                      • 2
                                      • Suisse

                                      #19
                                      Re: LG 50PZ550-UA Plasma has no picture or sound

                                      Thanks to you guys, now I know that my 50PZ950S as a faulty mainboard as the test partern is perfect.
                                      Does anyone know how much heat (in Celsius please) and how much time it should be placed in hoven for a good reflow ?
                                      In Swizterland LG ask me 240 Chf for this board - I may order it from the UK !
                                      And don't forget: never buy LG shit again !

                                      Comment

                                      • tmxmnz
                                        New Member
                                        • Mar 2017
                                        • 2
                                        • Suisse

                                        #20
                                        Re: LG 50PZ550-UA Plasma has no picture or sound

                                        Reflow (10 minutes, 200° C) does the job perfectly. How much time it will last ? Hope long enough so I can spare to buy a new TV ! I thank you so much for this guys, you're great.

                                        Comment

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