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    Samsung HPT5054....

    All,
    Got a Samsung hpt5054 plasma tv.

    Started with revolving relay on PSU.

    The 50 inch tv we found the y sustain board suffered from 3 bad caps, fuse,and a MOSFET that suffered failure...it failed relatively badly also involving a couple resistors possibly around the MOSFET. (burnt)

    Went route of replacing with a matching ysustain board.

    Not knowing a lot i checked the two y buffers....I did a continuity test but picked random connection on y sustain side and did quick across all pins on tv panel cable side (twice)...they appear to test good....but again not sure on the ysustain side if needed to be specific pin connection.

    Put replacement board in and now relay on psu looks good (no rolling).The voltages check out 208,63,15.

    The screen energizes...black screen...color static appears initially (second or less)...afterwards a occassional pixel lights up (not black)...the remote can turn on and off power to tv...but no picture/menu/etc.

    Someone suggested xmain board... i got a service manual...mosfets seem ok...fuses suggested to test seem ok...on xmain.

    Any suggestions?...verification its xmain....should i test ybuffer boards again?...Panel looks ok..used powerful LED light to check out panel for blemishes etc...would love detail description on how plasma tvs work.

    Thanks in advance,
    Chris
    Last edited by SolomonMan; 04-21-2019, 12:48 PM.

    #2
    Re: Samsung HPT5054....

    these buffer boards usually fail and blow the ymain. I got one here that needs ymain and buffers.

    Comment


      #3
      Re: Samsung HPT5054....

      awyatt2/All,
      Did the Y Buffer Continuity Test Again this morning...tried all pin combinations from the right side to Left Side....nothing is continuous.

      So I am thinking the Y Buffer boards are good....The Y sustain was a ebay purchase....possible bad board?... but guy has high ratings no negative marks and has been pretty helpful but says he believes/suggests the XMain....from looking at his ratings and currently for sale...has done TV boards for some time...says he tested board prior to shipment.

      I have the Service manual for the TV (found online)...tested things they suggested (fuses (f) on xmain)...went through the MOSFETs seem ok...nothing shorted except expected (I believe it was STTH40P03S) there are two on board and they act the same.

      I do notice the board took a lot of heat in the top part of things around the top row of vertical mosfets...

      Started tracing the board out not sure where to go from here other than just changing out the board...time vs money....?

      Maybe another thing to ask is there anything needed to be done after replacing the YSustain board...To Reset things? Or Another set of tests to point me in right direction?

      Thanks
      Chris

      Comment


        #4
        Re: Samsung HPT5054....

        Going from memory...

        Run the set with no buffers but everything else plugged in. When you turn it on if you have a Green led lit on the ymain you have a problem.

        Search on the forum here how to test the buffers.

        awyatt2 is correct about the buffers taking out the ymain and vice versa so you have to make sure all are in working order before attempting to use them together.

        Comment


          #5
          Re: Samsung HPT5054....

          All,
          I did some searching through the threads out there and it appears if the Y Sustain board lights up the LED that either the Buffer boards or the Y sustatin board is bad.

          I removed the Y Buffer from the Y Sustain and tried things again and the led on the Y Sustain is now off.

          I tried testing the Y buffer boards from the examples given in different threads out there and what I find is when I select my Ohm/Diode/Sound Continuity setting I do not get a sound but I get a 712-735 reading in many pins (Both upper and Lower Y Buffer Boards)...This is on my craftsman 82026 Multimeter.

          Now on my Klein Tools MM700...I do not get any reading nor sound...This meter is new to me.

          So I am wondering if its my craftsman meter and something else is lighting up the LED on the Y sustain when everything is back together (Panel?). Or maybe this craftsman meter is on to something...I do have a cheap harbor freight meter running around in the garage...Not sure...

          Any suggestions or ideas?

          Thanks
          Chris

          Comment


            #6
            Re: Samsung HPT5054....

            All,
            I quickly put in the boards to eliminate (at least in my mind) the panel being the cause\influence of the LED light being lit up on the Y sustain. I did not connect the Cables going into the panel to the buffer boards (Far Left while looking at the back of the TV).

            I saw no light when I powered things back up on the Y Sustain board....So the panel is not influencing the light.

            The LED check is being discussed in the below bad caps link;
            https://www.badcaps.net/forum/showth...HPT5054&page=2

            I am going to try another meter and\or swap out the craftsman battery on the multimeter later today and try things again.

            Thanks
            Chris

            Comment


              #7
              Re: Samsung HPT5054....

              mmartell,
              I just realized you were on the thread that I provided the link.

              Also I tried just the lower and upper boards separately and they both influenced the LED light on the Y sustain board to be lit up.

              I am going to try the continuity test this evening but I wonder if somehow I am doing something wrong like selecting the wrong connection point on the Y sustain to Buffer connection (Pleae note I am taking the Buffer boards out of TV and I am also just trying continuity on the buffer boards only.

              In either case I will focus on the Y buffers...

              Thanks for the help in advance and previously,
              Chris

              Comment


                #8
                Re: Samsung HPT5054....

                about .7xx is correct when checking the buffer ic's in diode mode, once you find a common point (on the black connector) and read .7xx to one of the pins on the panel plug end, all the other pins should read aprox the same, if one reads 0Ω, that line in the ic is shorted.
                Last edited by R_J; 04-28-2019, 12:38 PM.

                Comment


                  #9
                  Re: Samsung HPT5054....

                  R_J / All,
                  I did a diode mode test as R_J suggested and I was able to verify the top Y Buffer has 3 pins on each of the white connections which are bad.

                  They were not quite 0 but something like .009 or .010...one was .003.
                  Anyways once I was able to find it in Diode mode I used the sound selection and was able to find by sound the .003 and .009 ones.

                  The Lower board I could not find any issues with and I tested it twice...So are both boards dependent on each other in order to put the Y Sustain light off?

                  Should I replace both the top and bottom Y Buffer boards or just the top?

                  Thanks everyone for the help,
                  Chris

                  Comment


                    #10
                    Re: Samsung HPT5054....

                    Guys,
                    I was looking for a replacement on the YBuffer Board(s) and I see mentioned a few places that Y-Buffer LJ41-04218A/LJ41-04219A are a Replacement For LJ41-05121A and LJ41-05122A.

                    Below is just one location to buy but I am not affiliated in any way nor can I recommend...I am shopping it out/sourcing...

                    https://www.bonanza.com/listings/Y-B...DW2A/601411213

                    Can anyone verify this replacement part/part number is correct?

                    Thanks again
                    Chris

                    Comment


                      #11
                      Re: Samsung HPT5054....

                      Guys,
                      Got the new Buffer Boards in and we now have a plasma screen thats lit (not black) but not proper...I have included a pic of the screen.

                      The screen will occassionally go to half (left to right) for a second or so and then back to whats seen. It appears to be responding to what would be on screen. The sound still works and the Y Sustain board LED is no longer lit up.

                      If I pull one of the Far left Y buffer connections to the panel... a whole vertical section will disappear responding to which connection was pulled...which previously did not occur.

                      Likewise if I pull the XMain ribbon cable to the logic board...The screen will appear (similar to the pic) but will be much darker.

                      From my quick reading it leads me to think the Logic Board....Included some pics of the Logic board operation...There appears to be 4 LEDs...The one on the left is flashing consistently...There is one (not pictured) that lights up and then goes out after a brief period of time...The remaining two are always lit...Any Ideas?

                      Thanks for the help,
                      Chris
                      Attached Files
                      Last edited by SolomonMan; 05-17-2019, 07:14 AM.

                      Comment


                        #12
                        Re: Samsung HPT5054....

                        You'll need to run the test patterns by jumpering two pads on the logic board - haven't a clue where they are I can't see them in your pic.

                        Maybe someone else can tell you or if not read some of the previous threads on this set as I'm sure the info is in there somewhere.

                        Comment


                          #13
                          Re: Samsung HPT5054....

                          mmartell,
                          I beleive I supposed to cross pins 3 and 4....At least its briefly mentioned here.

                          https://www.badcaps.net/forum/showth...tterns+HPT5054

                          I also believe the pins to cross are in the image include and is circled in red.

                          I will keep looking to see what I can find in the forum...Anyone confirm?

                          Thanks
                          Chris
                          Attached Files

                          Comment


                            #14
                            Re: Samsung HPT5054....

                            That's the one. Put an old hard drive jumper on it if you have one and disconnect the lvds cable from the main board then plug it in and check out the patterns.

                            Comment


                              #15
                              Re: Samsung HPT5054....

                              mmartell,
                              Thanks for the response...yes I have more than a few of those jumpers from the 30+ years of computer stuff running around in my office.

                              I will try and get to this tonight.

                              I am assuming it will cycle through a set of color screens...What exactly am I looking for or testing.

                              Thanks
                              Chris

                              Comment


                                #16
                                Re: Samsung HPT5054....

                                Running the patterns bypasses the main board. If the patterns look good then you know your ysus/buffers are good and the main board is likely to blame.

                                If the patterns look bad then you still have more troubleshooting to do...

                                Comment


                                  #17
                                  Re: Samsung HPT5054....

                                  mmartell,
                                  Tried pins 3-4 with the lvds cable disconnected. The same type of screen previously displayed showed up. Two of the vertical bars seemed a little more pronounced (darker) a little less color but same screen. Tried pins 1-2 and 5-6 separately and the same screen as 3-4 was displayed.

                                  Not sure where I should look now...?

                                  Thanks for the help,
                                  Chris

                                  Comment


                                    #18
                                    Re: Samsung HPT5054....

                                    mmartell,
                                    After thinking about things...Should I start with the yBuffers again and test?

                                    Thanks
                                    Chris

                                    Comment


                                      #19
                                      Re: Samsung HPT5054....

                                      The presence of static in the pictures you posted makes me think you have problem still on your ysus. Where did you get this replacement board ?

                                      The fact nothing changed when running the test patterns says the main board is not the culprit.

                                      The fact you have a full raster indicates the buffers are functioning.

                                      So at this point I would guess in order of likelyhood that the ysus is to blame, and if not then the control board. Control board is cheap might want to try that first.

                                      Comment


                                        #20
                                        Re: Samsung HPT5054....

                                        mmartell,
                                        The board came from ebay...

                                        https://www.ebay.com/itm/SAMSUNG-Y-S...72.m2749.l2649

                                        Said it was fully tested on a working TV....The guy has been pretty helpful and in fact persistent on whether I have had any sucess on getting the TV running again...as I put the project on hold while doing a bunch of house remodeling.

                                        I assume the control board... is the Logic Board I posted a picture of just recently...?

                                        If so, yes its fairly inexpensive and readily available....

                                        Is it common to lose a Y Sustain, Y Buffers, and a logic board all at once?

                                        The original Y Sustain board appears to have had some serious heat/burning when it went out....and its all in line with things.

                                        Again thanks for the help,
                                        Chris

                                        Comment

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