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42" Maxent Plasma MX-42XM11 Lines on screen

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    #1

    42" Maxent Plasma MX-42XM11 Lines on screen

    Hey guys! I just got a 42" Maxcent plasma TV with a problem. I turn on the TV and at first it works perfect, but after time passes, say about a minute or 2, a couple lines start flashing, and as more time passes, more lines appear and start flashes as you can see in the picture. I would turn off the TV wait a couple of minutes and turn it back on and the lines have disappeared depending how long i leave it off.

    Whats could be a cause of these lines appearing? Could it be some component receiving excess load, and as I turn it off it discharges and begins to act normal again? Which components would usually cause this?

    I'm in the process of removing the back panel right now to find the main board. Would anyone happen to have a service manual? I don't think I need it but it would make things much easier though! thanks
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    #2
    Re: 42" Maxent Plasma MX-42XM11 Lines on screen

    Bad buffer possibly, or control board issue.

    Does it appear to cover the OSD?

    On all inputs?

    On the "no signal" display?
    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: 42" Maxent Plasma MX-42XM11 Lines on screen

      The lines do go over the OSD and over the "no signal display", all the inputs are effected with the lines going over the osd, but then certain inputs would flashes lines and then go to pure blue screen (no lines)
      Last edited by tieny; 02-29-2012, 01:37 PM.

      Comment

        #4
        Re: 42" Maxent Plasma MX-42XM11 Lines on screen

        Originally posted by tieny View Post
        The lines do go over the OSD and over the "no signal display", all the inputs are effected with the lines going over the osd, but then certain inputs would flashes lines and then go to pure blue screen (no lines)
        Sounds like a main board problem.

        Got a hair dryer? Get the TV in working condition and start heating up parts... if goes wrong then let it cool down and heat the part up later to double check.
        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

          #5
          Re: 42" Maxent Plasma MX-42XM11 Lines on screen

          Hmm interesting method, are there any parts in particular I should check?
          Heres photos of the all the boards within the tv.

          The photos are a bit blurry, if you need a close up of one part just circle which one and ill take a better picture since its pretty big.
          Attached Files

          Comment

            #6
            Re: 42" Maxent Plasma MX-42XM11 Lines on screen

            The lines are starting to appear on screen faster now. Now it would take no longer then 5 seconds for the screen to be filled.

            Heres one more photo I forgot of a board that was under the video board.
            Attached Files

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              #7
              Re: 42" Maxent Plasma MX-42XM11 Lines on screen

              Do the check on anything with a big processor on it. Power supply and sustain boards probably aren't at fault.
              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: 42" Maxent Plasma MX-42XM11 Lines on screen

                The lines are starting to appear too fast for me to do the check, any other ideas?

                Does anyone know anything about Zener diodes? At first thought I found a shorted diode because it measured a resistance of 1 ohm in both directions but I found out I think it's a zener diode? It's right under the smaller transformer in the second photo, zd501.
                Last edited by tieny; 03-01-2012, 08:01 AM.

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                  #9
                  Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                  Originally posted by tieny View Post
                  The lines are starting to appear too fast for me to do the check, any other ideas?

                  Does anyone know anything about Zener diodes? At first thought I found a shorted diode because it measured a resistance of 1 ohm in both directions but I found out I think it's a zener diode? It's right under the smaller transformer in the second photo, zd501.
                  Freeze spray, or compressed air (if you invert a can of compressed air while spraying it, it becomes freeze spray.) Cool parts until the problem goes away. Careful with the moisture from the can as it may be conductive.
                  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: 42" Maxent Plasma MX-42XM11 Lines on screen

                    Which is the power supply board and which is the main board?

                    Comment

                      #11
                      Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                      Originally posted by tieny View Post
                      Which is the power supply board and which is the main board?
                      Power supply connects to the sustain boards and main power connector.

                      First photo is main board... second is PSU.

                      Main board usually has all of the inputs on it.

                      ZD501 does sound suspect, you would need to pull it though to make sure it's not in parallel with anything else causing the odd reading.
                      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: 42" Maxent Plasma MX-42XM11 Lines on screen

                        The 1st photo is the current problem at its maximum. (The worst it'll get when left on for awhile)

                        I pulled the diode and measured it but it gave me no readings, (Do diodes fail by open circuit? Whats the difference between a zener diode?) The ends of the diode look black, rusted or burned. The label on the diode reads T2D 40.

                        I then measured the points of where i pulled the dioded and that gave me the reading of 1 ohm. (points in photo 3) The points still seem to be connected and I guess the diode was placed in parallel with it.

                        Should this be the problem? Any thoughts
                        Attached Files

                        Comment

                          #13
                          Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                          Unless you have an old analog multimeter, virtually all digital multimeters come with a diode test function. Use that to test your diode. See your manual.
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                            #14
                            Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                            I set my multimeter to diode mode, but theres still no read (open circuit perhaps), checked and no continuity either. I tested other diodes and i got their readings fine.

                            Comment

                              #15
                              Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                              Originally posted by tieny View Post
                              I set my multimeter to diode mode, but theres still no read (open circuit perhaps), checked and no continuity either. I tested other diodes and i got their readings fine.
                              Did you check the zener in both directions? If so, it is bad.

                              PlainBill
                              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                              Comment

                                #16
                                Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                                Yes I tested both directions, where can I find a replacement part for this diode? I searched up t2d 40 but not sure what I'm looking for exactly.

                                Comment

                                  #17
                                  Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                                  The diode is fine, zeners appear open circuit normally.

                                  Besides it's for the standby supply if it wasn't working the TV wouldn't work.

                                  Note something interesting. The background video seems more or less okay, but the OSD is scrambled in places. It's like the OSD which is embedded onto the main image has been corrupted. In other words, it looks a lot like a main board issue.
                                  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

                                    #18
                                    Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                                    Even with the zener removed, the TV still works as it did before and with the lines. I'll look into the main board and try to find any faulty components.

                                    Comment

                                      #19
                                      Re: 42" Maxent Plasma MX-42XM11 Lines on screen

                                      Originally posted by tieny View Post
                                      Even with the zener removed, the TV still works as it did before and with the lines. I'll look into the main board and try to find any faulty components.
                                      The zener probably provides local transient protection - It must be replaced to ensure proper operation. It will probably work for a couple of days without it, but then go pop.

                                      The zener is highly unlikely to cause problems in that position.
                                      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: 42" Maxent Plasma MX-42XM11 Lines on screen

                                        What are the specs for the zener? I can't seem to figure out the code marking

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