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Phillips 50PF7321D/37 Plasma slow reboot

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    Phillips 50PF7321D/37 Plasma slow reboot

    Customer said if he keeps it on for a long time, turns it off, and later back on, it takes 10 minutes to get to proper brightness. Is this just a cap issue? I didn't have time to take it apart I was just there to drop a repaired laptop off
    Cap Datasheet Depot: http://www.paullinebarger.net/DS/
    ^If you have datasheets not listed PM me

    #2
    Re: Phillips 50PF7321D/37 Plasma slow reboot

    Here are the boards

    LJ44-00125A Main
    LK41-04084A Y

    It takes an hour to get to screen (audio stays on during this time). Customer said used to take 30m and got longer.

    I notice a few bloated on the Y board and like one on the main.

    Refurbished pictures show those replaced, some at higher uf, but should I replace the main caps? Main and medium? Total recap?
    Attached Files
    Cap Datasheet Depot: http://www.paullinebarger.net/DS/
    ^If you have datasheets not listed PM me

    Comment


      #3
      Re: Phillips 50PF7321D/37 Plasma slow reboot

      Keep in mind I've never been familiar with plasma before, especially any TV this old

      Oh shit one of the bloated ones is under a Fet heatsink on the main. I'm going to have to unscrew all the fets, and unsolder the heatsink?
      Cap Datasheet Depot: http://www.paullinebarger.net/DS/
      ^If you have datasheets not listed PM me

      Comment


        #4
        Re: Phillips 50PF7321D/37 Plasma slow reboot

        Looks like you have a couple more caps bulging out that need replaced.
        Last edited by nomoresonys; 03-05-2022, 08:08 AM.

        Comment


          #5
          Re: Phillips 50PF7321D/37 Plasma slow reboot

          Being a plasma and probably at least 10 years old, a total recap might be best policy.

          Comment


            #6
            Re: Phillips 50PF7321D/37 Plasma slow reboot

            Originally posted by nomoresonys View Post
            Looks like you have a couple more caps bulging out that need replaced.
            Yeah one is under a fet heatsink. Does Putting heatshrink on it protect it from that fet sink heat? Or does it make it worse. I've seen this used on PSU's

            Originally posted by nomoresonys View Post
            Being a plasma and probably at least 10 years old, a total recap might be best policy.
            Even the tiny ones?
            Cap Datasheet Depot: http://www.paullinebarger.net/DS/
            ^If you have datasheets not listed PM me

            Comment


              #7
              Re: Phillips 50PF7321D/37 Plasma slow reboot

              I think i would just change the thru hole electrolytics, then give it a good long test.

              Comment


                #8
                Re: Phillips 50PF7321D/37 Plasma slow reboot

                Originally posted by nomoresonys View Post
                I think i would just change the thru hole electrolytics, then give it a good long test.
                Not SMD but the ones about 1/4 high
                Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                ^If you have datasheets not listed PM me

                Comment


                  #9
                  Re: Phillips 50PF7321D/37 Plasma slow reboot

                  I don't see any real little electrolytics on those boards.

                  Comment


                    #10
                    Re: Phillips 50PF7321D/37 Plasma slow reboot

                    Welp I did a near 90% of the Y and power board, and it still does it.

                    It was heavily used for 15+ years, I think the screen has lost it's plasma
                    Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                    ^If you have datasheets not listed PM me

                    Comment


                      #11
                      Re: Phillips 50PF7321D/37 Plasma slow reboot

                      damn, that's bad luck, I hate heavy old klunky plasma tvs, I know a lot of people say they're great, but I wonder what would be worse, if they were all in the landfill (because most don't bother to recycle) or just keep the electricity hogs going and use up the rest of the energy resources that are left. I can carry a 60 inch led tv with ease but I need two and a half men to deal with a plasma, lol. But the screens don't shatter every time you tap them, that's one good thing.

                      Comment


                        #12
                        Re: Phillips 50PF7321D/37 Plasma slow reboot

                        Yeah he told me it came up after about an hour. Maybe it's the Z board. But at this point fuck it
                        Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                        ^If you have datasheets not listed PM me

                        Comment


                          #13
                          Re: Phillips 50PF7321D/37 Plasma slow reboot

                          In that case I would desolder and measure the caps you have not replaced yet on a ESR and capacitance meter.
                          Because if you're anyway going to scrap it there is nothing to loose and you might just find that there is some other bad cap somewhere.
                          "The one who says it cannot be done should never interrupt the one who is doing it."

                          Comment


                            #14
                            Re: Phillips 50PF7321D/37 Plasma slow reboot

                            I'm probably going to wait for him to get a new TV some day because his money is scarce but he slowly saves up for non-critical stuff. For the time being it does work, I just told him to not turn it off, mute it at night lol

                            Is it possible for a plasma TV to...I don't know...burn through plasma? Loose usable plasma?

                            I don't have an ESR meter. It's not often these days I actual do cap replacement anymore
                            Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                            ^If you have datasheets not listed PM me

                            Comment


                              #15
                              Re: Phillips 50PF7321D/37 Plasma slow reboot

                              Well a way to narrow it down would be to heat the boards one by one to around 50°C or so.
                              If heating one of them shortens the startup time significantly you know you found your culprit.
                              "The one who says it cannot be done should never interrupt the one who is doing it."

                              Comment


                                #16
                                Re: Phillips 50PF7321D/37 Plasma slow reboot

                                Originally posted by Per Hansson View Post
                                Well a way to narrow it down would be to heat the boards one by one to around 50°C or so.
                                If heating one of them shortens the startup time significantly you know you found your culprit.
                                Yup. It finally got to the point where it stopped coming on after 45 mins, so he got me over there and I took back off and ran my heat gun on the Y board and it booted. Usually the screen does not come back on, unless after the y board is warm, it's turned off and back on, then it comes on. I replaced so many caps on the Y board, what component would likely cause this issue?
                                Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                                ^If you have datasheets not listed PM me

                                Comment


                                  #17
                                  Re: Phillips 50PF7321D/37 Plasma slow reboot

                                  The likely component would be a capacitor, but it can be any component really, or even a solder joint.
                                  You might be able to narrow it down further by doing more localized heating of components and or areas of the board...
                                  "The one who says it cannot be done should never interrupt the one who is doing it."

                                  Comment


                                    #18
                                    Re: Phillips 50PF7321D/37 Plasma slow reboot

                                    Could it have it have been board I didn't replace any caps on? Anyone have the schematic to see what it is?
                                    Attached Files
                                    Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                                    ^If you have datasheets not listed PM me

                                    Comment


                                      #19
                                      Re: Phillips 50PF7321D/37 Plasma slow reboot

                                      These generate secondary Y voltages, like VSCAN and whatever.

                                      While it's trying to turn on, what voltages produced by the Y-SUS are present? If one of them is missing then it's easy to isolate, if all of them are present, try heating exclusively the main heatsinks idividually, that's the IPMs.

                                      This board should generate two types of voltage, one of them is VSCAN, and the other is the equivalent to -VY, since this is a Samsung board I can't find any test points and only one of the trimpots is labeled(YRR).

                                      Comment


                                        #20
                                        Re: Phillips 50PF7321D/37 Plasma slow reboot

                                        I was never able to get leads on it.

                                        I'll heat up that board when I get over there and see if it's the culprit
                                        Cap Datasheet Depot: http://www.paullinebarger.net/DS/
                                        ^If you have datasheets not listed PM me

                                        Comment

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