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Pink sparklies and voltage - Panasonic P42UT30B

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    #41
    Re: Pink sparklies and voltage - Panasonic P42UT30B

    That pink diffusion just looks like dithering if it's moving around. When maldischarge due to low Vsus occurs then it tends to stick on the panel. Example:
    https://www.youtube.com/watch?v=ROYHWY79784

    You can see some of it in my video, in my case Vsus is far lower than it should be due to the bulb. But generally you get static pink patches and discharge issues as the picture brightens. Pink tends to be the first colour noticed because the green subpixels require a slightly higher activation energy to successfully discharge.

    It might be that the TV is compensating for phosphor degradation and upping the gain on the green. To resolve this detail it will use a dither pattern across the panel. The plasma screen does not have a great deal of graduation steps (only ~1000 or so) without dithering, so it is a necessary feature. On most panels it is completely unnoticeable - I own several Panasonic PDP TVs and it is notable that Panasonic invested a lot of money into getting the dither patterns and algorithms right and that if you view the TV from its design distance of about 1.6m to 2m it is invisible. Note that beyond 1.6m the 1080p resolution of the panel is unresolvable to anyone with 20/20 vision.

    If it's not visible from ordinary viewing distance I'd say it's not a fault and by design. The UT30B was Panasonic's entry-level 3D panel, so they had to make a few compromises which probably means it will dither more than a premium-line model like a GT or VT series. It was a first for the budget 3D plasmas (2011) and only a year after their high-end VT20 model which also supported 3D (& 1st proper commercially sold 3D TV, IIRC). Samsung had its entry out a couple of months later (D490) but by any account, having seen both panels, I would say that the Panasonic has it beat...and if you want to see dithering, you need only see a budget Samsung plasma panel. The black levels/graduations are almost entirely made up of dithered patterns!
    Last edited by tom66; 08-07-2017, 03:37 PM.
    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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      #42
      Re: Pink sparklies and voltage - Panasonic P42UT30B

      I repaired this model a few times , it has the same board as in the video. This y-sus is a bit smaller then in the 42ST30/GT30/VT30 and as tom says is the entry level tv.
      You are now probably seeing plasma dithering. You still could try to follow the steps that i said in last post and see if it changes anything because i did not have this fault on the repaired models. ( Did not see pink picture ).

      This still could be a mainboard issue , i had a few of these models that had failed bga solder under the GPU chip displaying weird pictures and/or half screen etc. In this case it is a gamble.

      Does it happen on all inputs?
      I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

      Comment


        #43
        Re: Pink sparklies and voltage - Panasonic P42UT30B

        Originally posted by tom66 View Post
        That pink diffusion just looks like dithering if it's moving around. When maldischarge due to low Vsus occurs then it tends to stick on the panel. Example:
        https://www.youtube.com/watch?v=ROYHWY79784

        Note that beyond 1.6m the 1080p resolution of the panel is unresolvable to anyone with 20/20 vision.
        I had been a firm subscriber to this but recently had cause to buy a new TV and side-by-side the picture quality (and perceived resolution) is significantly worse on my P42UT30 at 1080p than my new 50CX802 Panny at 4k. Might be the size difference I suppose. Probably getting off track by worrying about this.

        Originally posted by tom66 View Post
        If it's not visible from ordinary viewing distance I'd say it's not a fault and by design.
        It is visible from my seated position approximately 2 metres away.

        Originally posted by jonnyapps View Post

        In light blue is the position these two potentiometers were in when I opened the TV up. Pink is the position I've had to move both to in order to eradicate the sparklies. They were moved counter-clockwise, towards a number 1 on the PCB and away from a number 3. This has been done in combination with setting VSUS to 'high' in the service menu.
        If this change worked to eradicate the pink noise would it suggest it isn't dithering?

        Originally posted by Moreno83 View Post

        Does it happen on all inputs?
        Yes and from multiple devices and visible in the service menu test screens.

        I intend to take your advice on checking the back of the board. I've just been trying to avoid that process in the hope that something simpler fixes the issue as I reaaaaally suck at soldering.

        I will try to film the effect but it is proving difficult to get anything but weird colours and refresh rate flickers. Perhaps if I change the input to 24hz I might get a better result from my phone camera.

        Thanks again for all the help you're both providing.

        Comment


          #44
          Re: Pink sparklies and voltage - Panasonic P42UT30B

          Well, of course a 50" 4K screen would have higher perceived resolution than a 42" 1080p panel . That is from the same distance. However you will find that if you put up a standard test pattern of a checkerboard that the 4K and 1080p checkerboards will be roughly the same - they should appear grey at two metres. If you actually can see the difference then you are perhaps amongst a few percent of people that have better than 20/20 vision.

          There is disagreement on exactly where the point is where higher resolution matters, and it is different for everyone, but many say around sit back around 3-4x the screen diagonal size.

          In terms of colour accuracy and black level (an important factor for night viewing), a UT30B should beat most LED-backlit LCD TVs, except some of the ones using regional dimming, but they are really rare nowadays. This depends on the set being configured correctly.

          If this change worked to eradicate the pink noise would it suggest it isn't dithering?
          Yes indeed it would. Please do note if there is any difference.

          I will try to film the effect but it is proving difficult to get anything but weird colours and refresh rate flickers. Perhaps if I change the input to 24hz I might get a better result from my phone camera.
          If you have a camera that lets you control shutter during shooting, set it to 1/50 or longer. The way a plasma screen refreshes causes odd effects on recorded video.
          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


            #45
            Re: Pink sparklies and voltage - Panasonic P42UT30B

            Originally posted by tom66 View Post

            Yes indeed it would. Please do note if there is any difference.
            It's definitely better with the initial adjustments from my original post.

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              #46
              Re: Pink sparklies and voltage - Panasonic P42UT30B

              Originally posted by jonnyapps View Post
              It's definitely better with the initial adjustments from my original post.
              Well that is good. This is with the lower Vsus?
              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


                #47
                Re: Pink sparklies and voltage - Panasonic P42UT30B

                Originally posted by tom66 View Post
                Well that is good. This is with the lower Vsus?
                "They were moved counter-clockwise, towards a number 1 on the PCB and away from a number 3. This has been done in combination with setting VSUS to 'high' in the service menu"

                I'll go back and check this though as reducing VSUS but then setting it to high doesn't seem to make sense and I was also reducing the VDA (assuming that second pot being moved counter-clockwise is also a reduction in voltage).

                Comment


                  #48
                  Re: Pink sparklies and voltage - Panasonic P42UT30B

                  Can you indicate what Vsus and Vda are on now?
                  And yes, decreasing Vsus and then setting it to high is a bit odd.
                  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


                    #49
                    Re: Pink sparklies and voltage - Panasonic P42UT30B

                    Originally posted by tom66 View Post
                    can you indicate what vsus and vda are on now?
                    And yes, decreasing vsus and then setting it to high is a bit odd.
                    211
                    52.1

                    Set like that the pink sparklies on white are gone but I notice them in grey now.
                    Time to check the back of the board I guess!

                    Comment


                      #50
                      Re: Pink sparklies and voltage - Panasonic P42UT30B

                      Originally posted by Moreno83 View Post
                      Oke , first things first because i got the idea your accidentally skipping some possible solutions. Did you tighten ALL the screws on every board including C boards?

                      Could you please do the following?
                      Turn tv off and lay the tv on a soft cloth/table etc with the screen facing down.
                      Remove the power and sc20 cable from the scboard and remove all the screws from the board.

                      Flip the board gently to the left and see if you notice any black marks on the sc board and chassis holes. If so , then take a solder iron and resolder the pads. Only need little solder.
                      If you don't have a solder iron then scrape the black resideu off the board and chassis.
                      Reinstall the board and screws and tighten them. Does it change anything?

                      If not , try to alter the Vsus voltage a little. Place the tv on its stand and use a small screw driver to alter the vsus voltage with 2 / 3 v and see if it gets better. Maybe use a mirror so you can see what you are doing. If there is almost no difference then there are a few options left. ( Don't forget the meter so you can read the voltage , 2v can do ALOT so be careful ).

                      Possible solutions:

                      1) Try to set V-sus to HIGH in service menu
                      2) Replace the mainboard , maybe the GPU is bad causing maldischarge.
                      3) Worst case scenario is that the panel is failing.

                      The buzzing sound that you are hearing is the plasma panel , usually on bright pictures.

                      Let us know what you find!
                      I don't see an SC-board listed in the manual. I do see an SN-board with an SN20 cable. Is that the one?

                      Comment


                        #51
                        Re: Pink sparklies and voltage - Panasonic P42UT30B

                        Yes that is the same board! But your board is not defective , unless a chip is failing but i doubt that....

                        Its the left board!
                        Last edited by Moreno83; 08-10-2017, 09:19 AM.
                        I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                        Comment


                          #52
                          Re: Pink sparklies and voltage - Panasonic P42UT30B

                          Ps , can you adjust the voltage to 215V?

                          Most 30 series have the voltage on 215V and a few on 209 but you said it got better with 211V. Please try 215v.
                          I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                          Comment


                            #53
                            Re: Pink sparklies and voltage - Panasonic P42UT30B

                            Originally posted by Moreno83 View Post
                            Yes that is the same board! But your board is not defective , unless a chip is failing but i doubt that....

                            Its the left board!
                            Just had a look. A few black marks on the screw hole undersides. Cleaned them up but no major effect.

                            Also tried at 215v and no major effect there either.

                            Comment


                              #54
                              Re: Pink sparklies and voltage - Panasonic P42UT30B

                              Then it is either panel of mainboard....

                              Did you tighten ALL screws on all boards?
                              I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                              Comment


                                #55
                                Re: Pink sparklies and voltage - Panasonic P42UT30B

                                Originally posted by Moreno83 View Post
                                Then it is either panel of mainboard....

                                Did you tighten ALL screws on all boards?
                                Yes I did.

                                Thanks for all over the help everyone's provided in this thread.
                                I've reached the end of the experimentation I'm willing to do and as I now have a new TV will sell this one with the explanation of the problem and what I've tried.

                                Thanks again for a wonderful resource and fantastic help!

                                Comment


                                  #56
                                  Re: Pink sparklies and voltage - Panasonic P42UT30B

                                  Your welcome! Ps , your better of selling the parts. Especially the working sc board.
                                  I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                                  Comment


                                    #57
                                    Re: Pink sparklies and voltage - Panasonic P42UT30B

                                    @jonny, I am down in London in a month's time and I'm happy to buy the TV off you 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

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