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    #41
    Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

    Originally posted by tom66 View Post
    Unlikely to be an issue. The board operates on 390V (the PFC voltage) plus there will be some transients due to the LLC switching edges not being perfect, but still well under the 1000V rating.

    At a guess, they used 1250V because it was the most economical price or was the only product available from a preferred vendor at the time.
    So I soldered in the new capacitors. There is no change in behavior of the unit. Vs still does not come up when plugging in the television.

    I also tested the capacitors I removed from the TV. They both seemed to be within specifications of 0.033 μF.

    Is there anything else you recommend I try before I send the board out to PTS electronics?

    Thank You.
    Attached Files
    Last edited by FrivolousShrimp; 08-26-2017, 01:04 PM.

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      #42
      Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

      Unfortunately not without doing comprehensive diagnosis of the circuit.

      I hope PTS can fix it, try seeing what they have replaced.
      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


        #43
        Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

        Originally posted by tom66 View Post
        Unfortunately not without doing comprehensive diagnosis of the circuit.

        I hope PTS can fix it, try seeing what they have replaced.
        Thank you for all the help in trying to solve this issue. At least we narrowed it down to the most likely culprit. And I learned a few things along the way. I'm going to ship the board out on Monday. When I get it back, I'll let you know the outcome.

        Comment


          #44
          Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

          Originally posted by tom66 View Post
          Unfortunately not without doing comprehensive diagnosis of the circuit.

          I hope PTS can fix it, try seeing what they have replaced.
          So it has been awhile since I've posted an update. I finally received the PSU back from PTS. They didn't include any information as to what they fixed. I have gone ahead and sent them a message asking for specifics. As soon as I receive a response, I'll post it here. I've attached a photo of the board now. The only thing i can differentiate is the stickers they have attached at the top left. Other than that, I can't tell what they have done.

          Now, after installing the repaired PSU, I am seeing voltages coming back. However, the screen is now snowy, slightly purple, and very dim. I went ahead and disconnected and reconnected all the ribbon and power cables to make sure that everything is seated properly. I've also run the logic board test pattern, and it shows the same purple hue with snowy pattern.

          These are the current voltages I am reading:

          Vs: is 214V s/b 217V
          Va: is 52V s/b 55V
          Ve: is 91V s/b 91V
          Vsc: is -193V s/b -197V

          I adjusted the potentiometers as far as I could. The ones for Vs and Va cannot be adjusted up any higher than they are now. The same goes for Vsc. The only one within range is Ve. I'm not sure if a few volts would cause the picture to be bad as it is.

          I'll get on the phone with PTS this week and see if they have any feedback on not being able to meet the VS and Va voltages. If anyone has any suggestions in the meantime, please let me know. Thanks.
          Attached Files

          Comment


            #45
            Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

            Ah, now that is an X-main issue. Vs down a few volts unlikely to cause major issues, though worth investigating with PTS.

            Jesus, something did a number on your set...!

            Check power and data lines to X-main are fully connected; check all the FPCs are installed; check all screws are secure.
            Last edited by tom66; 09-11-2017, 12:38 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


              #46
              Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

              Originally posted by tom66 View Post
              Ah, now that is an X-main issue. Vs down a few volts unlikely to cause major issues, though worth investigating with PTS.

              Jesus, something did a number on your set...!

              Check power and data lines to X-main are fully connected; check all the FPCs are installed; check all screws are secure.
              I have no idea what happened to the set. It had been intermittently going in and out for a few months, and one day just completely died. If we had a power surge, or something to that effect, you would think that other electronics would have been damaged in our home. But nothing else is exhibiting any issues.

              Could I ask what are FPCs?

              Comment


                #47
                Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                FPCs are ribbon cables just make sure there all fitted correctly in the sockets etc

                Comment


                  #48
                  Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                  Originally posted by FrivolousShrimp View Post
                  I have no idea what happened to the set. It had been intermittently going in and out for a few months, and one day just completely died. If we had a power surge, or something to that effect, you would think that other electronics would have been damaged in our home. But nothing else is exhibiting any issues.

                  Could I ask what are FPCs?
                  Flat printed connectors (so-called because they are basically flexible printed circuit boards, which are made similarly to a rigid circuit board but without the rigid bit in the middle ). EDIT: Vince beat me to it. Make sure all of them are seated in place (should be from 2 to 6 of them.) These are on the X-main side. Don't fiddle with the Y-buffer ones; they're a pain to reseat, so only touch them if you really need to .

                  As for the fault, it's very very unlikely for a cascading failure to occur in such a manner on a plasma or LCD TV. You occasionally hear of an X-main damaging a Y-main or a Y-main damaging the buffers, but it's pretty rare for that to go beyond those parts. I have no idea what went wrong, but it was catastrophic, however it happened.

                  The good news is, since you can see a dim picture, it confirms:
                  - Power supply
                  - Most of Y-main and Y-buffers
                  - Control board (probably*)
                  - Main board

                  are all working in good order. You are seeing "underdiffusion" right now where the panel is only getting half of its rated sustain voltage because the X-main is missing or not driving the panel properly.

                  *there is a small, very small chance that the control board could fail in such a manner that it could fail to generate correct X-main signals, but I have only ever seen this failure once and it was due to physical damage to the control board.
                  Last edited by tom66; 09-11-2017, 12:27 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


                    #49
                    Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                    Originally posted by tom66 View Post
                    Flat printed connectors (so-called because they are basically flexible printed circuit boards, which are made similarly to a rigid circuit board but without the rigid bit in the middle ). EDIT: Vince beat me to it. Make sure all of them are seated in place (should be from 2 to 6 of them.) These are on the X-main side. Don't fiddle with the Y-buffer ones; they're a pain to reseat, so only touch them if you really need to .

                    As for the fault, it's very very unlikely for a cascading failure to occur in such a manner on a plasma or LCD TV. You occasionally hear of an X-main damaging a Y-main or a Y-main damaging the buffers, but it's pretty rare for that to go beyond those parts. I have no idea what went wrong, but it was catastrophic, however it happened.

                    The good news is, since you can see a dim picture, it confirms:
                    - Power supply
                    - Most of Y-main and Y-buffers
                    - Control board (probably*)
                    - Main board

                    are all working in good order. You are seeing "underdiffusion" right now where the panel is only getting half of its rated sustain voltage because the X-main is missing or not driving the panel properly.

                    *there is a small, very small chance that the control board could fail in such a manner that it could fail to generate correct X-main signals, but I have only ever seen this failure once and it was due to physical damage to the control board.
                    So I swapped out the X-main board. The picture still looks the same. I've checked all the connections, and they seem fine.

                    Is the green LED on the logic board supposed to blink when the set is on?

                    I received a response from PTS. It is a bit cryptic. This is what they said:

                    Your board was repaired it failed for power issues. Due to cold solder joints. Thank you and have a great day.


                    The grammar isn't exactly clear.

                    I'm just about ready to throw in the towel on this thing.

                    It's looking like a OLED purchase may be in my future.

                    Comment


                      #50
                      Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                      Ah I really hope you don't give up. We are really close! OLED is a nice image, but they burn in really quick. The local Costco has OLED screens with burn in from the channel logos. A shame at the price they cost.

                      I think they meant to say your set had cold solder joints on some of the transistors. Rare failure. Will have to look at your pictures and check it out for myself, because I didn't see any when I first looked, though it can be hard. If you post a picture of the X-main, I'll highlight some test points.

                      And yes, the LED on the control board should blink approx once a second. (It blinks every 32 frames, with 60Hz image then it's about once a second. 50Hz it's longer, and so on.)
                      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


                        #51
                        Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                        Originally posted by tom66 View Post
                        Ah I really hope you don't give up. We are really close! OLED is a nice image, but they burn in really quick. The local Costco has OLED screens with burn in from the channel logos. A shame at the price they cost.

                        I think they meant to say your set had cold solder joints on some of the transistors. Rare failure. Will have to look at your pictures and check it out for myself, because I didn't see any when I first looked, though it can be hard. If you post a picture of the X-main, I'll highlight some test points.

                        And yes, the LED on the control board should blink approx once a second. (It blinks every 32 frames, with 60Hz image then it's about once a second. 50Hz it's longer, and so on.)
                        I'll keep trying if you have any ideas left! There is a picture of the X-sus on the first post when I started this thread. The camera flash is hiding the Ve test point, but the rest of the board looks pretty clear. Let me know if you need a better photo.

                        I was at Costco the other day and saw the OLED. I didn't have much time to look at it. But it was nice from the brief glance I took at it. Next time I pop in, I'll make a closer observation and check out the burn in issue.

                        I should have stuck with Panasonic plasmas. My two 50" units never had an issue. I had to install a chip in the G10 to reset the hours counter so it didn't keep raising the power level and killing the blacks. Other than that, never any problems. I also bought a S30 for the guest room, and it's going great.

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                          #52
                          Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                          Yep, Panasonic plasmas are solid. I fixed a PZ80 for my mum with the very common 10 blink code caused by failure of a small ceramic cap on the PSU. It now is three years since it was fixed, and has 33,000 hours on it. You wouldn't know it -- the panel is frickin' pristine. The only downside is the average power consumption is like 350W for a 42" screen! My 42" ST50B is only ~130W.

                          Try checking the Ve and Vs test points on the X-main; also check the voltage across both blue highlighted caps on the X-main (see attachment).
                          Attached Files
                          Last edited by tom66; 09-14-2017, 01:46 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


                            #53
                            Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                            Originally posted by tom66 View Post
                            Yep, Panasonic plasmas are solid. I fixed a PZ80 for my mum with the very common 10 blink code caused by failure of a small ceramic cap on the PSU. It now is three years since it was fixed, and has 33,000 hours on it. You wouldn't know it -- the panel is frickin' pristine. The only downside is the average power consumption is like 350W for a 42" screen! My 42" ST50B is only ~130W.

                            Try checking the Ve and Vs test points on the X-main; also check the voltage across both blue highlighted caps on the X-main (see attachment).
                            Unfortunately I could not find a 65" VT or ZT Panasonic in my area when I was looking for a larger television. I spent a couple months scouring the classified ads with no luck; other than one person selling a ZT for a ludicrous sum. The Samsung I found for only $600. It served me well for 2 years, until it decided to quit and this thread started.

                            So I tested the voltages you asked for.

                            Ve = 91V

                            If the Vs you're looking for is the one at the top labeled SVC_Vs, I am seeing 215V.

                            As for the capacitors, I cannot get a consistent reading. The voltages bounce from 0V-40V. I even saw a number as high as 86V on the lower one. But that was extremely brief. If you have any suggestions as to what I should look for here and how to test, I could use the help.

                            I disconnected all the ribbon cables from the X-buffer and reconnected them. There was no change. I even tried booting up the unit with the X-buffer ribbon cables disconnected, and I still got the same picture.

                            Comment


                              #54
                              Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                              Yeah, keep looking myself for a 55" VT50 or similar set for my living room; saw a GT30B but didn't want to go down in performance: the ST50B's blacks are fucking good, especially when you consider it was only the mid-range set. "Gravity" on this TV looks amazing. Then again, the U30B in my bedroom ain't no slacker either.

                              Ve looks about right...a little on the low side but Samsung have often been found using low Ve voltage (X-bias initialisation voltage.)

                              So, there should be a similar bank of caps on the Y-main, can you check those? The voltage is definitely not right. It should be steady at about half the Vs voltage for most pictures on the screen. I'd expect, since your Y-main seems to be working, to see the steady ERC voltage there.

                              Do you have access to an oscilloscope, or know someone who does? It might be worth seeing if you can borrow one. Plasma TV repair is difficult without one.
                              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


                                #55
                                Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                                Originally posted by tom66 View Post
                                Yeah, keep looking myself for a 55" VT50 or similar set for my living room; saw a GT30B but didn't want to go down in performance: the ST50B's blacks are fucking good, especially when you consider it was only the mid-range set. "Gravity" on this TV looks amazing. Then again, the U30B in my bedroom ain't no slacker either.

                                Ve looks about right...a little on the low side but Samsung have often been found using low Ve voltage (X-bias initialisation voltage.)

                                So, there should be a similar bank of caps on the Y-main, can you check those? The voltage is definitely not right. It should be steady at about half the Vs voltage for most pictures on the screen. I'd expect, since your Y-main seems to be working, to see the steady ERC voltage there.

                                Do you have access to an oscilloscope, or know someone who does? It might be worth seeing if you can borrow one. Plasma TV repair is difficult without one.
                                I checked the capacitors on the Y-main. The ones at the top are a steady 215V, I forgot what the lower ones are. My notes are back at home. However, they were at a steady voltage, not varying. It seems the Y-main is functioning as it should be.

                                I'll ask around and see if I can find someone with an oscilloscope. It's not a tool most people typically have around. Out of curiosity, what would I be checking with the oscilloscope?

                                Comment


                                  #56
                                  Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                                  The oscilloscope would be useful for checking the X-main output. We can also check the control signals going from the control board to the X-main to verify that bit is working.

                                  Since your control board had a failure, there's a small chance that a problem exists on it relating to the control board signals that drive the X-main.

                                  Completely throwing this out there, but here's a possible failure path:
                                  - X-main shorts its output through gate driver chip (The 200V or so Vsus becomes exposed directly on the 15V and 5V gate drivers)
                                  - This energy travels back to the control board, blowing the fuse, damaging one of its drive outputs and damaging the power supply. (Doesn't explain PTS's statement about the fault, but they've historically been shy about saying what they 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


                                    #57
                                    Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                                    Originally posted by tom66 View Post
                                    The oscilloscope would be useful for checking the X-main output. We can also check the control signals going from the control board to the X-main to verify that bit is working.

                                    Since your control board had a failure, there's a small chance that a problem exists on it relating to the control board signals that drive the X-main.

                                    Completely throwing this out there, but here's a possible failure path:
                                    - X-main shorts its output through gate driver chip (The 200V or so Vsus becomes exposed directly on the 15V and 5V gate drivers)
                                    - This energy travels back to the control board, blowing the fuse, damaging one of its drive outputs and damaging the power supply. (Doesn't explain PTS's statement about the fault, but they've historically been shy about saying what they fix.)
                                    So perhaps the logic boards is faulty then. ShopJimmy has them for $24. It wouldn't be too much trouble to order one and test it out.

                                    I'm still asking around about the oscilloscope. Typically I have no reservations about buying tools for any job, but I can't see myself using an oscilloscope again in the future.

                                    Comment


                                      #58
                                      Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                                      Yeah...An oscilloscope would be a big investment. I bought one for repair and playing with electronics, but I used to do 10 TV's a month!

                                      If you don't get the scope, might be worth trying the logic board, especially if it's returnable.
                                      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


                                        #59
                                        Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                                        Originally posted by tom66 View Post
                                        Yeah...An oscilloscope would be a big investment. I bought one for repair and playing with electronics, but I used to do 10 TV's a month!

                                        If you don't get the scope, might be worth trying the logic board, especially if it's returnable.
                                        It is definitely not an inexpensive tool. If I knew purchasing it would guarantee solving this issue, I might consider it. I don't plan on fixing televisions regularly, so I can't really justify the cost. It sounds like you made a return on your investment pretty quickly.

                                        I replaced the logic board with one from ShopJimmy. There has been no change in the behavior of the television. PTS electronics came back with a bit more detailed response to my inquiry as to what they repaired:
                                        I just got a response for the techs and they said it had cold solders on TS801S and TS802S. The techs believe you have a bad main board issue. Thank you and have a great day.

                                        At this point, it looks like I might be stuck. I guess I can call a repair technician out. Hopefully they aren't too ridiculously priced. I doubt that being 3V low on Vs would be causing this. Not sure where else to go from here. There is a 65" Panasonic TH-65VX300U for sale not too far from me. I'm considering maybe making the drive and picking it up to replace this unit.

                                        Let me know if you have any other thoughts. Thanks again for all the help.

                                        Edit: Looks like this guy had the same issue. Doesn't appear it was resolved and he stopped posting: https://www.badcaps.net/forum/showthread.php?t=45209
                                        Last edited by FrivolousShrimp; 09-23-2017, 03:04 PM.

                                        Comment


                                          #60
                                          Re: Samsung Plasma PN64D7000 Flashing Red LED No Power

                                          It is a difficult issue.

                                          If you are stuck on the issue, I would suggest selling the TV for parts as-is. Maybe someone else is willing to repair it, if they have the experience.

                                          The 65" LED set would not give you anything close to the same picture quality, if I were in your shoes, I would look for a Samsung PN64F8500 or a Panasonic TX-P65VT50/VT60 set. There are a few members on these forums that have gt good deals on these. Failing that, a 65" 1080p LG OLED, but it'll cost you a lot.
                                          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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