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LG 50PS80 plasma: Moving rows/array of blue dots in black

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    #1

    LG 50PS80 plasma: Moving rows/array of blue dots in black

    My LG 50PS80 plasma, which is around 3 or 4 years old, has developed an issue. I was watching TV last night and noticed these cool bright blue dots in the black scenes on the screen and thought it was part of the show I was watching. It wasn't until the screen went full black that I saw this (see attached pic please) These blue lines are made up of little blue dots and the entire array of lines/dots is moving left and right all in succession. It's sort of bouncing left and right on the screen a few inches. I left the TV off overnight and this afternoon turned it on to find many more lines. The entire screen is basically covered with these blue lines to the point that black is no longer there. Has anyone seen this before? I'd greatly appreciate some input on which board to look at for an issue or is the panel failing? When I bring up a menu the menu looks great except that the reds are more pink than red and any black area has blue dots/lines in it.
    Thanks.
    Attached Files
    Last edited by traderx; 10-20-2013, 03:48 PM.
    Tags: None
    #2
    Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

    Looks like a control board issue. Probably not the panel and not too expensive to repair.

    Can you provide a picture of the boards inside the set? There is a quick and simple test which will show if the control board is bad.
    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

      #3
      Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

      Tom, thank you for the very quick reply. I appreciate it. I am at work for the remainder of the day, EST zone (I see you are UK) just wanted to get the thread started. I will pull the back off and get photos posted tomorrow. When the TV was brand new it had moving green sparkles in the blacks on the entire screen, but this was only visible when you were a few inches from the TV. Today the whole screen, with no input areas that should be black, were just covered with bright blue lines. I'll get more pictures up as soon as I can
      Thanks,

      Comment

        #4
        Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

        So here are some photos of the TV as requested. First grouping shows the current issue.
        Attached Files

        Comment

          #5
          Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

          And now for the guts: I located the logic board. Everything is nice and planted, cables are held in place with yellow tape. I reseated the cables and what I believed to be the LVDS cable, basically any cable that wasn't taped down. I powered up the panel and it gave me the same results. So now I'm uploading the photos and will wait for further tips. I might just try to locate that logic board online and purchase one. Let me know if I should be checking something else. I see that I can short pin 1 and 2 on "AUTOGEN" header on the logic board with LVDS cable unplugged according do a document I got off your website. looks like pin 1 is unmarked, but I presume it's from left end of the connector as is standard?
          Otherwise looks good inside - no puffed up caps, no burn marks.
          Attached Files

          Comment

            #6
            Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

            So I just removed the LVDS cable between the logic board and the input board. I then jumped pin 1 and 2 on the logic board "AUTOGEN" and powered it up. The screen ran through it's sequence of test patterns and color charts/greyscale sweeps. Everything looked beautiful. I've never seen blacks so deep on this display and whites so crisp. Green and Red were flawless too. I let it loop 3 times. I never saw any issue with it. So at this point the logic board is OK and I need a new main board? Or do I have that wrong.
            Thanks for your help.
            Last edited by traderx; 10-21-2013, 12:09 AM.

            Comment

              #7
              Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

              Hah, looks like you found the issue. The main board, which is the board with the video inputs on it, is the problem child. (The control board is OK.) The control board will send unadulterated pure RGB to the display, with no colour correction. White is white, black is black. I'll bet the black didn't have green sparklies either?
              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

                #8
                Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                Originally posted by tom66 View Post
                Hah, looks like you found the issue. The main board, which is the board with the video inputs on it, is the problem child. (The control board is OK.) The control board will send unadulterated pure RGB to the display, with no colour correction. White is white, black is black. I'll bet the black didn't have green sparklies either?
                That is correct Sir, the black was deep deep black with no moving green sparkles in it. Never seen it that black. White was clean white, color charts and sweep test patterns were all clean. RED was pure red, not pink. I'm ordering board # EBT60722601. I hope it's in working condition. Thanks for all of your help.

                Comment

                  #9
                  Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                  Probably on your old board the brightness was not set correctly -- just out of interest try turning that down, or the contrast down slightly on the old board before you replace that. (Won't fix the issue but will show if that is the cause.)
                  Last edited by tom66; 10-21-2013, 12:40 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.

                  Comment

                    #10
                    Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                    I had to run out, but will update you with that test when I get back to the TV this evening. I believe I kept the video setting on the THX certified calibration setting.

                    Comment

                      #11
                      Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                      Please note if you've had the set professionally calibrated, you'll have to note down your current settings and copy them across to the new board.
                      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

                        #12
                        Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                        Good evening Tom, thanks for your reply, here is a snapshot of the current video settings for brightness/contrast etc. This is the setting I've been using since I got the TV new. Looks like contrast is 70, brightness at 50. I tried lowering the brightness and contrast. It made no difference where I set those settings. There was a subtle change in brightness/contrast but the array of blue dots was still burning strong. At this point I'm awaiting delivery of the new main board from CA. Should take a week unfortunately with snail mail. Photo is attached of the settings I've been using. Are they within spec? I don't think I was over-driving the display. It probably gets run about 40 hours a week or so. Mostly during football season. The white and grey banding that is seen in the photo is caused by my cell phone camera. It's having an issue with the screen refresh rate. It's not visible to the eye. -- As a side note, I rolled out my old Hitachi 42HDS52A plasma from storage. Nice TV, but it's only 1080i. It's from 2006 and has not been used in about 2 years. It's working fine right now, but as I was around behind the TV I hear a faint buzzing noise from the PSU board that fades in and out. Is that a sign of failing/dried up caps?
                        Cheers,
                        Attached Files
                        Last edited by traderx; 10-21-2013, 10:52 PM. Reason: I can't type

                        Comment

                          #13
                          Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                          I was talking more of the green dots your set originally suffered from - typically lowering brightness to the point at which they go away works well. I can see the same effect on my Panasonic plasma when the brightness is too high though the dots are a mix of faint red and green.

                          It's normal to get a slight buzz from a plasma in operation that varies with picture intensity, so I wouldn't worry about it too much. The Hitachi is actually 1080p capable -- 1080i display but to the human eye that looks like 1080p. However, it lacks the correct amount of horizontal resolution, only 1024 pixels, making it equivalent to a 720p plasma released today.
                          Last edited by tom66; 10-22-2013, 02:33 AM.
                          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

                            #14
                            Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                            Tom, the green dots are no longer visible at all now that this blue dot problem has surfaced so I can't test for that by adjusting the brightness. I can't get enough working black area of the screen to be able to test for that. When I ran the control board test patterns, however, there were no green dots or any color dots of any kind in the black charts. They were pure black. I would presume that running the panel at 50% brightness would be in a safe range without overdriving components. Perhaps this main board had a factory defect which took 4 years for the component(s) to finally fail completely. If the shipped in main board fixes the issue I will try to determine the fault with the old board and post my findings. I'm hoping its just failed surface mount caps.

                            I always did like the Hitachi, great picture, it just was lacking a lot of features so it had to be replaced. However, I did love the motorized swivel you could control from the remote. That was a neat toy

                            Regards
                            Last edited by traderx; 10-22-2013, 03:49 AM.

                            Comment

                              #15
                              Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                              Well the new board arrived today, turned out they shipped it priority mail which is awesome. Just installed it. Seems to work fine, I'm in the process of testing all of the inputs, LAN connection, etc. Here are some Photos. There are no more green sparkles in the blacks, but now there are blue sparkles in the red areas if you are a few inches from the screen. Still it's a 100% improvement over the trippy blue dot mess I had in the beginning of this post. As you can see the blacks are very deep black and colors are vibrant. Please let me know if you notice any issues with the panel and/or new mainboard from the photos. The video is from the TVs built in Netflix so it's not Blu-ray quality, but still looks pretty good. Thanks again for your help. I Probably would have gone out and purchased a new LED-LCD tv without this forum and your input. Sadly it would have been a Samsung 7000 or 8000 series, but after reading your other posts It looks like I would have regretted that purchase based on the failures in under 4 years with Samsung LEDs. So your help was appreciated.
                              Cheers,
                              X
                              Attached Files
                              Last edited by traderx; 10-23-2013, 11:37 PM.

                              Comment

                                #16
                                Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                                Slight "dithering" in solid colours is to be expected with all plasmas, it's due to how they work, however, you should not be able to see them at ordinary viewing distance. If you can't see it from ordinary viewing distance then it's OK.

                                Sadly, an LED-LCD, especially one from Samsung, is likely to disappoint massively. My dad's now 8 year old 720p 50" NEC plasma looks better than my brother's 1 year old ES8000 46" Smart Samsung LED.

                                Enjoy your plasma!
                                Last edited by tom66; 10-24-2013, 04:02 AM.
                                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

                                  #17
                                  Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                                  That's good advice. Thanks for the tip. I did always love the plasma over the LED LCD picture quality. It's a shame Plasma got killed off. I always wanted one of the Kuro sets. The only thing I do like about the LED-LCD is the weight. My two plasmas are around 90-100 pounds each. I took my old main board to work today and checked the surface mount caps with a cap checker. They all tested so I'm not sure how much more time I'll put into fixing the old board when I can buy a working one for 80 bucks. Just thought I'd give it a shot.
                                  Cheers.

                                  Comment

                                    #18
                                    Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                                    For tom66 or other knowledgeable folks out there:

                                    I have the EXACT same problem (blue dots aligned in horizontal stripes on all the black backgrounds) as traderx did with his LG 50PS80. However, I have the 60PS80 instead of the 50PS80. Two questions:

                                    1.) Can I assume the same solution (replace main board)?
                                    2.) If 1.) is a "yes" Is there a way to find the main board part number and a relatively inexpensive used main board?

                                    TV works great in all other respects...

                                    Thanks for your help and God bless you,
                                    DelawareGuy

                                    Comment

                                      #19
                                      Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                                      1) probably - to confirm though, do the same AUTOGEN test
                                      2) use the EAX123456789 (or similar) number printed on your main board to look up the part; and you can install the 50PS80 board in your 60PS80, there is no difference with the main A/V board.
                                      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

                                        #20
                                        Re: LG 50PS80 plasma: Moving rows/array of blue dots in black

                                        Wow tom66 -- SPECTACULARLY fast reply! Thanks!!

                                        Really appreiate the info. I'll get the courage up to take all those screws off and get at it...

                                        One quick revision -- it seems that the blue dot syndrome is now fading then going away after the set has been on a while. I'm assuming this may be heat related, but that's just an educated guess.

                                        Also -- any thoughts on where to find used parts other than googleing the part number?

                                        Thanks again and God bless you (again).

                                        Comment

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