lg 42px5r no picture with sound

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  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #41
    Re: lg 42px5r no picture with sound

    Originally posted by nalle077
    Yes that is the same board, I read on the little sticker on I have on my board, but I saw that 6870QYH002P was printed directly on the board

    But you did the measuring withe the black probe on the fuse right ?
    Yes. I can do more measurements now, as I'm currently in the office, but probably only for another 10-15 minutes.
    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

    • nalle077
      Senior Member
      • Mar 2009
      • 102

      #42
      Re: lg 42px5r no picture with sound

      Originally posted by tom66
      Yes. I can do more measurements now, as I'm currently in the office, but probably only for another 10-15 minutes.
      No that want be nessasary, Im going to order a new one with all the info you gave me, thank you very much, be back with the result
      By the way, do you cut the leads to the IPM or how do you do it, Favorite way was thinking about desolder, is it possible

      Comment

      • tom66
        EVs Rule
        • Apr 2011
        • 32560
        • UK

        #43
        Re: lg 42px5r no picture with sound

        Originally posted by nalle077
        No that want be nessasary, Im going to order a new one with all the info you gave me, thank you very much, be back with the result
        By the way, do you cut the leads to the IPM or how do you do it, Favorite way was thinking about desolder, is it possible
        Never done it before, thankfully. The usual suggestion is to cut the leads with a side cutter, remove the module, then desolder the leads individually.
        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

        • TechShui
          Senior Member
          • Jun 2011
          • 148
          • USA

          #44
          Re: lg 42px5r no picture with sound

          Hello nalle077,

          I've been working on a 42PC3D, the sister model of your TV. It uses all the same parts except for the buffer, which is all one piece (instead of upper and lower). And my Y sus is a different form factor, (mine is 6870QYH002B) but is practically the same, just smaller heatsink than yours, and some components are rearranged.

          My symptoms are EXACTLY the same: No picture, but there is sound; had 4 bad caps on the left side of the power board, I replaced them already. Still no picture.

          I want to bring something to your attention about the IPM test you did.

          Originally posted by nalle077
          Thanks.

          I have measured according to the site and I found 1 thing that might be wrong. On my IPM (not the one on the picture I have 4921QP1027Q) there is no "ERout" I have "ER_I0", "ER_LOW", "ER_HIGH", "ER_DN" and "ER_UP" I have short between "ER_I0" and "SUS_OUT" and that is of course because I have it on the board ( if "ER_I0" and "ERout" is the same?) but I have 293 ohm between "+VS" and "ER_I0" if I have black probe on "+VS" and red probe on "ER_I0" the other way around I have almost Infinite.
          What to think?
          Does anyone have the same card and can see if it is the same on that?
          That means you have your multimeter set to continuity.

          If you set it to Mega Ohms (20M) on your dial you will get something like 2.930 Mega Ohms. The reading are the same, but with a decimal point after the first digit.

          When I switch the probes with the dial set to continuity, I also get infinity.

          I have the same IPM as your TV, the IPM model is YPPD-J018C/J017C. (check your label if you want to be sure).

          Try the test again, with the dial on Mega Ohms.

          My test results are like this AFTER I replaced my IPM

          ER_UP to VSout @ 3.34 ~ 3.60 MegaOhms
          ER_UP to GND @ 4.05 ~ 4.07 MegaOhms
          ER_UP to SUS @ 0.00 MegaOhms (because its shorted on the board)
          SUS to GND @ 2.28 MegaOhms
          SUS to VSout @ 3.20 MegaOhms
          GND to VSout @ 0.07 MegaOhms

          They seem kind of low, especially the last one... makes me wonder if my solder joints weren't neat enough?

          With the red probe on the fuse, and black on GND I get 14.04 Mega Ohm
          Vice versa, black on fuse, red to GND gives a much lower 3.67 Mega Ohms

          ...Alas, I'm still hearing sound, but no picture.
          Any comments are welcome.
          I suspect the power board again.
          Last edited by TechShui; 02-29-2012, 08:28 PM. Reason: Added more readings

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #45
            Re: lg 42px5r no picture with sound

            Originally posted by TechShui
            I suspect the power board again.
            Have you checked for good Vs, Va etc.? How are the fuses on the boards?
            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

            • TechShui
              Senior Member
              • Jun 2011
              • 148
              • USA

              #46
              Re: lg 42px5r no picture with sound

              Hello Tom, good morning

              Something terrible seems to have happened... but I'll answer your question first: Yes, I have checked all the voltages, and rechecked after I installed the new IPM.

              The Ysus plug:

              4.97v (5v)
              0.00v (GND)
              59.4v (Vo)
              0.00v (GND)
              0.00v (GND)
              0.00v (GND)
              0.00v (NC) <-- should this be at zero? what does NC stand for?
              184.2v (VS)
              184.2v (VS)

              Now, on to the news. I got really excited today, because the TV actually had a PICTURE, and the backlight came ON for the first time. ...but my victory was short lived. I could hear a loud buzzing from my Z board.

              I turned the set off, unplugged the Z board to make sure.

              There was still buzzing! This time it was softer, coming from the Y board of course. I still saw a picture, with lots of mal discharge and black lines. So I tried to change the channel, then there was a loud CRACK , then 5 seconds later another "Crack", or pop if you will.

              I turned the TV off, unplugged it and proceeded to check all the fuses assuming two had gone out. But all the fuses are showing 0 so they're closed.

              And now the TV will NOT power up unless the Y board is disconnected, this sounds like my new IPM just got blown... Grrr! This seems to point again at the power board AND the Y board.

              EDIT: I think I found a problem, the 10-pin connected to the main logic board. Yesterday, it had two 6v, now it only has one, I double checked just now. Or am I going mad?

              Blue = 19.11v
              Blue = 19.10v
              Grey = 00.0v
              Grey = 00.0v
              Grey = 5.94v
              Grey = 0.01v <- This one should have 6v too, right?
              Grey = 3.37v
              Grey = 0.00v <- and this one seems odd, it shouldn't read 0 either
              Grey = 11.88v
              Grey = 0.00v
              Last edited by TechShui; 03-01-2012, 04:15 AM. Reason: mainboard voltages

              Comment

              • retiredcaps
                Badcaps Legend
                • Apr 2010
                • 9271

                #47
                Re: lg 42px5r no picture with sound

                Originally posted by TechShui
                0.00v (NC) <-- should this be at zero? what does NC stand for?
                No connection. 0.00V is the right reading.
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                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #48
                  Re: lg 42px5r no picture with sound

                  Originally posted by TechShui
                  Now, on to the news. I got really excited today, because the TV actually had a PICTURE, and the backlight came ON for the first time. ...but my victory was short lived. I could hear a loud buzzing from my Z board.

                  I turned the set off, unplugged the Z board to make sure.

                  There was still buzzing! This time it was softer, coming from the Y board of course. I still saw a picture, with lots of mal discharge and black lines. So I tried to change the channel, then there was a loud CRACK , then 5 seconds later another "Crack", or pop if you will.

                  I turned the TV off, unplugged it and proceeded to check all the fuses assuming two had gone out. But all the fuses are showing 0 so they're closed.

                  And now the TV will NOT power up unless the Y board is disconnected, this sounds like my new IPM just got blown... Grrr! This seems to point again at the power board AND the Y board.
                  Ah! Well, that's interesting... I got a 42PX5D from the local tip for Β£30. Plugged it in and the screen kinda glowed from the edges but then shut down so I immediately thought Z-sustain. I opened it up to find it had obviously been in a chain smoking home (or maybe a pub), as it was completely full of this awful brown dust. Cleaned some of the dust out and plugged it in. Screen lit up, but I hear this very loud buzzing, getting louder and louder over a couple of seconds until... CRACK, POP and a nice yellow spark from a MOSFET then it shut down. Uh oh, I thought the IPM had gone. Nope, it somehow managed to survive. The MOSFET had a bit too much dust on it and this was cleaned and it worked! As this TV has a fan I would check this before assuming the IPM was bad as the fan sucks in a *lot* of dust. My TV was completely clogged with it and I had the unfortunate job of inhaling a lot of it.

                  On my TV Vs measured 194V and Va measured 60V. It's okay for it to be a bit low, you'll get a dimmer picture though. I usually set it a couple volts below nominal on LG plasmas, it gets rid of most sparklies and prolongs the life of the panel and sustain boards, and the change in brightness is barely noticeable. (Too low, and you'll get no picture, but most PSUs on these TVs won't output very low voltages.)

                  Originally posted by TechShui
                  EDIT: I think I found a problem, the 10-pin connected to the main logic board. Yesterday, it had two 6v, now it only has one, I double checked just now. Or am I going mad?

                  Blue = 19.11v
                  Blue = 19.10v
                  Grey = 00.0v
                  Grey = 00.0v
                  Grey = 5.94v
                  Grey = 0.01v <- This one should have 6v too, right?
                  Grey = 3.37v
                  Grey = 0.00v <- and this one seems odd, it shouldn't read 0 either
                  Grey = 11.88v
                  Grey = 0.00v
                  Well, I have no clue - except that those are digital signals and it's likely that the low signal is coming from the sustain and going to the logic board telling it a fault has been detected.
                  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

                  • nalle077
                    Senior Member
                    • Mar 2009
                    • 102

                    #49
                    Re: lg 42px5r no picture with sound

                    Originally posted by TechShui
                    My test results are like this AFTER I replaced my IPM

                    ER_UP to VSout @ 3.34 ~ 3.60 MegaOhms
                    ER_UP to GND @ 4.05 ~ 4.07 MegaOhms
                    ER_UP to SUS @ 0.00 MegaOhms (because its shorted on the board)
                    SUS to GND @ 2.28 MegaOhms
                    SUS to VSout @ 3.20 MegaOhms
                    GND to VSout @ 0.07 MegaOhms

                    They seem kind of low, especially the last one... makes me wonder if my solder joints weren't neat enough?

                    With the red probe on the fuse, and black on GND I get 14.04 Mega Ohm
                    Vice versa, black on fuse, red to GND gives a much lower 3.67 Mega Ohms

                    ...Alas, I'm still hearing sound, but no picture.
                    Any comments are welcome.
                    I suspect the power board again.
                    I do not have the same names on the board and the multimeter is not so high quality so i will get another multimeter tomorrow.

                    here are a picture on the back of my IPM on the board
                    IΒ΄ll be happy if anyone can tell me what is the same points on my IPM
                    Attached Files

                    Comment

                    • TechShui
                      Senior Member
                      • Jun 2011
                      • 148
                      • USA

                      #50
                      Re: lg 42px5r no picture with sound

                      Nalle I wish I knew. But I obviously made a mistake in assuming our IPMs were the same. Yours has 42 pins, mine has 32.

                      Yours looks like a YPPD-J009C, is that correct?

                      You have already tested ER_IO and SUS_OUT on your board and it was shorted (probably because it's shorted on your board outside of the module).

                      And my ER_UP and SUS was shorted. So maybe that's where you should start probing?

                      Yours = Mine

                      ER_IO = ER_UP
                      SUSout = SUS
                      And tom, thanks for the tip, can I ask where exactly the MOSFET was located? Was it those tiny ones inside the IPM? Did you have replace it or simply clean the dust off?

                      Originally posted by tom66
                      Ah! Well, that's interesting... I got a 42PX5D from the local tip for Β£30. Plugged it in and the screen kinda glowed from the edges but then shut down so I immediately thought Z-sustain. I opened it up to find it had obviously been in a chain smoking home (or maybe a pub), as it was completely full of this awful brown dust. Cleaned some of the dust out and plugged it in. Screen lit up, but I hear this very loud buzzing, getting louder and louder over a couple of seconds until... CRACK, POP and a nice yellow spark from a MOSFET then it shut down. Uh oh, I thought the IPM had gone. Nope, it somehow managed to survive. The MOSFET had a bit too much dust on it and this was cleaned and it worked! As this TV has a fan I would check this before assuming the IPM was bad as the fan sucks in a *lot* of dust. My TV was completely clogged with it and I had the unfortunate job of inhaling a lot of it.
                      Last edited by TechShui; 03-01-2012, 08:12 PM.

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK

                        #51
                        Re: lg 42px5r no picture with sound

                        Originally posted by TechShui
                        And tom, thanks for the tip, can I ask where exactly the MOSFET was located? Was it those tiny ones inside the IPM? Did you have replace it or simply clean the dust off?
                        No, it was just on the board. I think I got lucky that it didn't need replacing but it might need replacement. Post a pic of your board, I'll highlight it for you.
                        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

                        • nalle077
                          Senior Member
                          • Mar 2009
                          • 102

                          #52
                          Re: lg 42px5r no picture with sound

                          Originally posted by TechShui
                          Nalle I wish I knew. But I obviously made a mistake in assuming our IPMs were the same. Yours has 42 pins, mine has 32.

                          Yours looks like a YPPD-J009C, is that correct?

                          You have already tested ER_IO and SUS_OUT on your board and it was shorted (probably because it's shorted on your board outside of the module).

                          And my ER_UP and SUS was shorted. So maybe that's where you should start probing?
                          It is correct that I have YPPD-J009A / YPPD-J009C. I have been very busy, so I did not have time to answer before, and I did not have time to measure yet , IΒ΄ll be back with the results.
                          Best regards

                          Comment

                          • TechShui
                            Senior Member
                            • Jun 2011
                            • 148
                            • USA

                            #53
                            Re: lg 42px5r no picture with sound

                            Originally posted by tom66
                            No, it was just on the board. I think I got lucky that it didn't need replacing but it might need replacement. Post a pic of your board, I'll highlight it for you.
                            Sorry for posting in a dead thread, but I'm still troubleshooting the Y-sustain in my 42PC3D-UD.

                            Here are the pictures of it. Please circle the mosfet that sparked on your set if you still remember.
                            Attached Files

                            Comment

                            • TechShui
                              Senior Member
                              • Jun 2011
                              • 148
                              • USA

                              #54
                              Re: lg 42px5r no picture with sound

                              And I have a more general for anyone to comment on.

                              When I replaced the blown IPM in my Y-sustain, the heatsink compound was dry and powdery, -- no good. So I cleaned it all off of the heatsink and used some Arctic Ceramique instead of silicon-based compound. I assumed this would help tranfer the heat better.

                              In the 5 or so minutes that I had the TV on and working. I noticed the Y-sus heatsink was getting hot (hotter than normal) at the same time the buzzing was getting louder. This all means that something was drawing too much current, right?

                              Or did my Ceramique compound somehow cause the overheating? It should've helped the problem, not make it worse. I applied 4-5 long strips of paste,knowing that it would spread out when I screwed the heatsink back onto the ipm. I've applied thermal paste to CPUs dozens of times before, but again my question is whether the much cheaper silicon-based paste is better suited for IPMs?

                              Comment

                              • budman67
                                New Member
                                • Dec 2011
                                • 7

                                #55
                                Re: lg 42px5r no picture with sound

                                First time here to post, so dont think im trying to be the expert but I have repaired several of these same problems, but on different models...but it comes down to the same faulted part. the IPM, which controls the voltages and signals to the rest of the y-sus. The LG 42PC3D had several caps(10Vdc 3300uf) swelled, on the main power board that caused the IPM to blow. Taking the IPM off the y-sus is time consuming, but at 45 dollars for that part, and 12 for all the caps, is alot cheaper than having a 4-500 dollar repair bill. Dont go out and buy a used board, they might work for a little bit, but go bad and you be in the same mess again...thanks for listening...brian

                                Comment

                                • TechShui
                                  Senior Member
                                  • Jun 2011
                                  • 148
                                  • USA

                                  #56
                                  Re: lg 42px5r no picture with sound

                                  UPDATE: Well, as it turns out, my Y-sus sparked and blew the IPM again, because of trace damage, the traces are pretty big, so I think I can repair them without much trouble.

                                  The IPM can actually be bought for $30 from Coppell TV

                                  Comment

                                  • arman960
                                    Senior Member
                                    • Sep 2012
                                    • 129
                                    • USA

                                    #57
                                    Re: lg 42px5r no picture with sound

                                    Hi tom66, I want to see if you can help me to repair my Y-sustain. I am working on Samsung LJ92-01200A board which came from SANYO DP42746 Plasma tv.

                                    Here is the link how to test IPM: http://blog.coppelltvrepair.com/2011_04_01_archive.html

                                    It says any combination of these four connection must not be shorted. But when I checked ER and SUS they seem like shorted. But I think both SUS and ER is grounded. AS my x-sus has the same IPM and it acts the same way. My x-sus is good.

                                    So I am kinda confused if my IPM is really bad or not. Please reply if you have any idea. Also the fuse near the IMP usually blows if the IPM is faulty
                                    Attached Files
                                    Last edited by arman960; 09-20-2012, 09:34 PM.

                                    Comment

                                    • retiredcaps
                                      Badcaps Legend
                                      • Apr 2010
                                      • 9271

                                      #58
                                      Re: lg 42px5r no picture with sound

                                      Originally posted by arman960
                                      Hi tom66, I want to see if you can help me to repair my Y-sustain. I am working on Samsung LJ92-01200A board which came from SANYO DP42746 Plasma tv.

                                      Here is the link how to test IPM: http://blog.coppelltvrepair.com/2011_04_01_archive.html

                                      It says any combination of these four connection must not be shorted. But when I checked ER and SUS they seem like shorted. But I think both SUS and ER is grounded. AS my x-sus has the same IPM and it acts the same way. My x-sus is good.

                                      So I am kinda confused if my IPM is really bad or not. Please reply if you have any idea. Also the fuse near the IMP usually blows if the IPM is faulty
                                      @arman960.

                                      What did I tell you not to do?

                                      https://www.badcaps.net/forum/showpo...7&postcount=40

                                      I just answered your post in another thread and here I see it again.

                                      If you want help from me in the future, STOP cross posting. Keep everything in one thread.
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                                      We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

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                                      Comment

                                      • nalle077
                                        Senior Member
                                        • Mar 2009
                                        • 102

                                        #59
                                        Re: lg 42px5r no picture with sound

                                        Hello again.

                                        I have been busy with moving and building so I have not been online for a while ( And have had no time for TV-repair )

                                        I hate giving up so I really want this fixed.

                                        Anyway I have changed the IPM and the problem is the same. TV starts but picture or backlight does not come on.

                                        Any suggestions on what to do next ??

                                        Comment

                                        • nalle077
                                          Senior Member
                                          • Mar 2009
                                          • 102

                                          #60
                                          Re: lg 42px5r no picture with sound

                                          Originally posted by nalle077
                                          Hello again.

                                          I have been busy with moving and building so I have not been online for a while ( And have had no time for TV-repair )

                                          I hate giving up so I really want this fixed.

                                          Anyway I have changed the IPM and the problem is the same. TV starts but picture or backlight does not come on.

                                          Any suggestions on what to do next ??
                                          Hello !! Anyone there????

                                          Comment

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