Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

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  • bobbworth
    New Member
    • Nov 2013
    • 7
    • USA

    #1

    Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

    Wow, wonderful community here! I'm hopeful one of the extremely gracious souls who frequent it can help me keep our family's 7year old Maxent plasma running. I've searched through past threads here for a couple hours, but haven't found precisely the issue I'm seeing and so am prevailing on the charity and knowledge of those who have helped so many others.

    So, the rundown:

    I purchased this set in Jan '06 and have recently had an issue with the display. The first sign of trouble was several months ago: The image on screen would flicker a few times from cold power-on before recovering and then remaining clear. That behavior persisted until last night when after being on for ~50 minutes we suddenly started seeing vertical bands of noise across the whole display. (See attached photos.)

    This noise will start after the set warms up with a few dozen pixels going wonky across the whole display and within seconds progress to what you see in the photos, sometimes with more or less noise. It is a pretty consistent pattern once it appears, though it sometimes disappears entirely for brief periods (a minute or two at most).

    Another clue to whatever the issue is: If I "tug" on the set (wall-mounted) the noise will sometimes disappear entirely. Alternately, it will sometimes increase in proportion to how much I move the set.

    The noise does cover the OSD. It appears on all inputs, but only while searching for and displaying a signal. If no signal is detected after a couple seconds, the set displays a clear blue screen.

    My ultimate question is: "Can I fix this myself reliably for less than ~$600?" I do not have the luxury of tinkering endlessly, and don't have the skills or tools to solder, but I am capable of re-seating cables or purchasing/replacing a board if there's a high probability of success.

    Thank you for any insight!
    Bob
    Attached Files
  • freakaftr8
    Badcaps Legend
    • Oct 2012
    • 3743
    • USA

    #2
    Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

    yes if you remove the back cover not the hole cover but the that small cover covering up the mainboard for all the input connections you will see an IC with a green heatsink on it it'll be the hottest of all of them push on that heat sink and see if it goes away if it does you have a bad solder connections between that I see in the board itself this is a known problem with this model.
    Did I leave the soldering iron on?

    Comment

    • tom66
      EVs Rule
      • Apr 2011
      • 32560
      • UK

      #3
      Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

      Pictures of the chassis will help - this will most likely use an LG or Samsung panel and could have a control board defect, usually cheap to fix.
      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

      • capkid
        Badcaps Legend
        • Oct 2010
        • 1339
        • United States

        #4
        Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

        It appears that either the logic control board or the main board is faulty. You could try cleaning the cable connections with electronic contact cleaner. The logic boards are usually around $20 if you want take a gamble.

        Does the TV flicker if it's left with the blue screen displaying?
        LG Plasma Mal-Discharge Correction Service

        Comment

        • bobbworth
          New Member
          • Nov 2013
          • 7
          • USA

          #5
          Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

          Wow, thank you all for the incredibly quick replies!

          @tom66: Would a pic of the mainboard suffice? Or should I pull the whole big cover off and get pics of everything?

          @freakaftr8: I've taken the set off the wall and put it on its stand to be able to access the back while its on. After being on for 30+ minutes.... no noise. So, I tried using a hair-dryer directed at the IC's heatsink, and still nothing. I'll leave the set on and continue checking it tonight and report back.

          @capkid: No flickering or noise if it's showing blue screen with no signal. Yes noise if it's blue screen while searching for signal.

          Comment

          • capkid
            Badcaps Legend
            • Oct 2010
            • 1339
            • United States

            #6
            Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

            A pic of the whole back of the TV would be best.
            LG Plasma Mal-Discharge Correction Service

            Comment

            • bobbworth
              New Member
              • Nov 2013
              • 7
              • USA

              #7
              Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

              @freakaftr8: Alright, I've started seeing noise again, and yes, I can confirm that pressing with moderate force on the square green heatsink causes the noise onscreen to disappear. Sidenote: I removed the frame that the mainboard is attached to so I could get a picture of the board underneath it., and now that I'm seeing noise again, it's no longer vertical but instead horizontal blue lines.

              @capkid: Photos of the whole unit and the mainboard specifically are attached. I have close-ups of the other components too if it would help to have a clearer look at any one in particular.

              I gather then that the mainboard is the issue. I see full boards available starting at ~$90 and going as high as ~$300. I also see a repair kit for ~$20. What's my best option: buy the whole board or buy the kit and find someone locally to assist with the repair? Or is there an option C?

              Thank you all again for your help and support!
              Attached Files

              Comment

              • capkid
                Badcaps Legend
                • Oct 2010
                • 1339
                • United States

                #8
                Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

                I would say that it's best to have the board repaired, since this. is a common issue
                LG Plasma Mal-Discharge Correction Service

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #9
                  Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

                  I would focus on that RAM chip next to the green heatsink (surface mount no lead BGA), more likely that is the issue. Looks like EtronTech?
                  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

                  • bobbworth
                    New Member
                    • Nov 2013
                    • 7
                    • USA

                    #10
                    Re: Maxent MX50X3 [P500550HM8] 50" Plasma - Vertical bands of noise

                    Thank you both again for the speedy replies. I've only had time to follow up further today.

                    @tom66: You're spot-on. Yes, the module is manufactured by EtronTech. Where a moderate pressure on the heatsink corrects the issue, only the slightest touch to the RAM chip has an effect. From what I've seen you post elsewhere on this board, it sounds as though reballing a BGA is a delicate task – How do I go about getting this repaired?

                    Comment

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