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Samsung 50" Plasma HPT5044 No Picture

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    #61
    Re: Samsung 50" Plasma HPT5044 No Picture

    I would try and get a better one. Single channel, looks out of focus... avoid.
    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.

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      #62
      Re: Samsung 50" Plasma HPT5044 No Picture

      Thanks, guess I'll have to keep looking.

      what usually causes a drain-source short for a transistor?

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        #63
        Re: Samsung 50" Plasma HPT5044 No Picture

        Put simple running too hot for too long.

        When the device gets hot localised hot spots form on the die itself. These hot spots tend to hog all of the current due to their lower resistance. The lower resistance leads to more current through that part, and more heat. More heat makes them have an even lower resistance. You can see the cycle. If unmanaged, it becomes self-destructive and the hot spots become short circuits, which causes the device to fail short circuit.
        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.

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          #64
          Re: Samsung 50" Plasma HPT5044 No Picture

          I see, so the initial problem would be excess current? Thus starting the cycle and eventually short circuiting it.

          For the new MOSFET I just replaced in my Ysus, I only turned the TV on and off for only less than seconds and the drain-source easily shorted. Can a nearby shorted resistor be the cause of this?

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            #65
            Re: Samsung 50" Plasma HPT5044 No Picture

            Ill try and describe what he replaced- as you are looking at the board from the angle where the component of mine had a hole burned in it- The component itself (the one you pictured) plus a small flat onboard (resistor?) next to it and the right hand FET on the heat sink right above the hole-burned component. There is a kit on ebay to repair and it looks like he did about 1/2 of what that provides. http://www.ebay.com/itm/LJ92-01490A-...item3f123998c4

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              #66
              Re: Samsung 50" Plasma HPT5044 No Picture

              Heres a photo, I'm guessing these are the components? Which resistor did he replace, 1 or 3?
              Attached Files

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                #67
                Re: Samsung 50" Plasma HPT5044 No Picture

                The one not circled to the right of the fet that is soldered to the motherboard (not the heat sink)

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                  #68
                  Re: Samsung 50" Plasma HPT5044 No Picture

                  Oh okay I got it now. Anyway I just bought myself a scope just need a probe for it, you know any place to get a one?

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                    #69
                    Re: Samsung 50" Plasma HPT5044 No Picture

                    Just bought a S-1330 Elenco 30 Mhz oscilloscope.

                    Okay! So how do we do this? =) What I'm I looking for when testing if the Ysus is good or not?
                    Last edited by tieny; 12-20-2012, 10:06 AM.

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                      #70
                      Re: Samsung 50" Plasma HPT5044 No Picture

                      Have you got an overhead shot of the Y-main?
                      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.

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                        #71
                        Re: Samsung 50" Plasma HPT5044 No Picture

                        Here you go
                        Attached Files

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                          #72
                          Re: Samsung 50" Plasma HPT5044 No Picture

                          Just looking for a probe for my scope. Will this work?

                          http://www.ebay.com/itm/New-Two-Osci...item484b3b7d96

                          Or
                          http://www.amazon.com/Oscilloscope-S...ds=scope+probe
                          Last edited by tieny; 12-20-2012, 09:26 PM.

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                            #73
                            Re: Samsung 50" Plasma HPT5044 No Picture

                            What is the input rating of the scope? e.g. 250V, will be written on the front near the input connectors.
                            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.

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                              #74
                              Re: Samsung 50" Plasma HPT5044 No Picture

                              it says 400Vpk MAX

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                                #75
                                Re: Samsung 50" Plasma HPT5044 No Picture

                                OK, so you can use those probes safely. You should use the 10X setting for plasma sustain boards, but at least switching over to the 1X setting won't damage the scope. Otherwise, if the limit were closer to 300V, I would have recommended a fixed (not switchable) 10X probe.
                                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.

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                                  #76
                                  Re: Samsung 50" Plasma HPT5044 No Picture

                                  Ok I finally received my probe in the mail. Probably getting the buffer boards after xmas.

                                  So how do I test if the Ysus is good or not?

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                                    #77
                                    Re: Samsung 50" Plasma HPT5044 No Picture

                                    K, probe here. Set your probe to 10X. Attach the probe hook (supplied in the packet) to the probe end, and attach the hook to one end of the red poly cap, away from the screw. Connect the ground alligator clip to the side of the screw.

                                    Note: This is for testing with buffers installed. Is that what you want to do?
                                    Attached Files
                                    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.

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                                      #78
                                      Re: Samsung 50" Plasma HPT5044 No Picture

                                      Is there a way to test the Ysus without the buffers installed? The last time I installed all three boards and turned on the TV, the new 88N30W Mosfet I just replaced shorted from drain-source. I just replaced the mosfet again, i don't want to blow it again.

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                                        #79
                                        Re: Samsung 50" Plasma HPT5044 No Picture

                                        What are we looking for on the scope for a good ysus?

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                                          #80
                                          Re: Samsung 50" Plasma HPT5044 No Picture

                                          See:
                                          http://www.tgohome.com/ServiceManual...&Search=Submit

                                          Page 51 has waveforms.
                                          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.

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