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    #1

    TC-P55gt31

    First I want to say thanks in advance for some help I need. I have the infamous tnpa5335 SC board that is giving me some trouble. I had the original 7 blink with shorted igbt's. I ordered a kit from SJ and everything was fine. I had a power up with SC led lit and buffers out and SC50 jumped. I had a shorted SU so I found a pair on ebay for $111.00. I checked them before I installed them. The tv came on and everything looked good untill about an hour later and big bang. I immediately unplugged it and was expecting to see something blown off the board. Nothing but a few more igbt's shorted. Originally I replaced Q421,422,423,401,402,403. Now I have Q661,621 and it seems 622 survived. I know there are tons of posts regarding this board, and I have successfully repaired 3 of the same boards and a few similar boards. I have even successfully repaired an SC that has about 50 parts to replace. I have read about every post regarding this board but I felt I may need some help. IC502 appears to be ok, I checked IC724 and got reading of pin 1 to center tab 7.2k ohm and pin 3 to center tab 17.1 k ohm. Q531 has over 3 meg across the out side pairs. I thought I may need to check a few other items but not sure what. The original kit was all 30f131 igbt's. I did clean up the ground pads on the board and panel and used the new style screws on both SC and SS boards. Any help would really be appreciated.
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    #2
    Re: TC-P55gt31

    I totally forgot to mention I also have shorted Q421,422,423 again and they are the 30f131

    Comment

      #3
      Re: TC-P55gt31

      just going through moreno's fun, he had something similar. have you measured the resistance on the gate driver resistors for Q421,422,423?

      Comment

        #4
        Re: TC-P55gt31

        I have measured so many things, I dont quite remember. But I do always ck the resistors and I know none were open or shorted. I just dont remember the value. I will double ck. tw, I thought I read one of your posts and it was an opti-coupler, but I couldn't find the post. I think it was component 16461?? I have never had one that I repaired blow up like this. Sounded like a firecracker. I guess from the sound, I was expecting to see more carnage on the board. I was happy the buffers survived or at least are not shorted.

        Comment

          #5
          Re: TC-P55gt31

          Originally posted by gdawg View Post
          I have measured so many things, I dont quite remember. But I do always ck the resistors and I know none were open or shorted. I just dont remember the value. I will double ck. tw, I thought I read one of your posts and it was an opti-coupler, but I couldn't find the post. I think it was component 16461?? I have never had one that I repaired blow up like this. Sounded like a firecracker. I guess from the sound, I was expecting to see more carnage on the board. I was happy the buffers survived or at least are not shorted.
          yeah I did but none of the Q421,422,423,401,402,403 were blown or blew.

          It was repeatedly Q661,621 622 623 . you can click on my profile and look at statistics, threads started to find it. No reports from home that it's gone again so quite satisfied the opto on mine was damaged

          Comment

            #6
            Re: TC-P55gt31

            I will double check all the resistors, but if I recall they were all 7.8 ohms in circuit of course. I guess I dont understand why 661 blew which originally it was ok, unless it was compromised from the others being shorted. I guess the way to go on this is to check everything in the circuit and replace the shorted parts and give it a go. Do the readings I got on 724 look ok. They seemed to start out high and then dropped to the values I listed. I do have a spare one so maybe i will just replace it to be sure.

            Comment

              #7
              Re: TC-P55gt31

              tw- thanks for the info to find your posts. I know you are the king at SC boards and that will help me a lot!! Thanks

              Comment

                #8
                Re: TC-P55gt31

                Originally posted by gdawg View Post
                I will double check all the resistors, but if I recall they were all 7.8 ohms in circuit of course. I guess I dont understand why 661 blew which originally it was ok, unless it was compromised from the others being shorted. I guess the way to go on this is to check everything in the circuit and replace the shorted parts and give it a go. Do the readings I got on 724 look ok. They seemed to start out high and then dropped to the values I listed. I do have a spare one so maybe i will just replace it to be sure.
                viscous circle, when q612-623 short, Q661 goes along for the ride that's what i found

                Comment

                  #9
                  Re: TC-P55gt31

                  So do you think Q621,623 blew which took out Q661. I did not replace those on the original repair and may be I should have. In the past, I only replaced the shorted IGBT's. Do you automatically replace Q621,623,661 when you redo one of these. When these blew, the opti-coupler came to mind, but of course I do have 421,422,423 blown again. Then I am thinking, maybe I got a bad one in my kit. I am sure they are from china. I sure want to get this one up and running as I have the stand, manual, wireless adapter, and two sets of 3d glasses.

                  Comment

                    #10
                    Re: TC-P55gt31

                    May be a dumb question, but on the Panasonic schematic, they have a colored line on some of the lines going to different components. Is it just voltage flow to the components???

                    Comment

                      #11
                      Re: TC-P55gt31

                      Originally posted by gdawg View Post
                      So do you think Q621,623 blew which took out Q661. I did not replace those on the original repair and may be I should have. In the past, I only replaced the shorted IGBT's. Do you automatically replace Q621,623,661 when you redo one of these. When these blew, the opti-coupler came to mind, but of course I do have 421,422,423 blown again. Then I am thinking, maybe I got a bad one in my kit. I am sure they are from china. I sure want to get this one up and running as I have the stand, manual, wireless adapter, and two sets of 3d glasses.
                      yes, what I'm wondering is if q421-423 this time took 621 etc which then took 661.

                      Don't have enough knowledge on this particular board yet . Does the opto match up to the readings I found in cct on mine?

                      Maybe work back through the drive ccts and replace the drive cct components for the IGBTs that blew and maybe 401-403, recheck the resistors including 401-403.

                      All I can share is effectively one of my boards blew q661 and the 621-623 bank of igbts shorted 4 times. twice i replaced those parts and it ran for less than a day. twice it failed at startup after a run. Third time it failed straight up, found the opto had an open cct diode, replaced and it's been fine since.

                      So there's obviously a few ways these can die.

                      PTS is an option although they may not touch the board now.

                      not sure about the colored lines in the schematic. It appears the 50" may use the same or similar board.

                      Comment

                        #12
                        Re: TC-P55gt31

                        Ok. I think I will just check everything related and if in doubt replace it. I already ordered parts and will report my results once installed. I think I attached the part kit I ordered. Thought I would ask how you replace the IGBT'S. I use my hot air station to remove and usually use forceps to remove from board so I dont pick up any caps or resistors in the molten solder. I have used two ways to install and one is soldering iron on the tab till it melts and kinda like sweat soldering copper I feed some solder under the tab and it sucks it in. I have also installed using the hot air and heating the IGBT till it melts the solder. I dont know if too much heat can damage the component though. What do you think? Thanks again for all your time helping and again- there is so much knowledge on this forum, it is amazing!!! Thanks to all.
                        Attached Files
                        Last edited by gdawg; 03-15-2016, 03:07 PM. Reason: spelling

                        Comment

                          #13
                          Re: TC-P55gt31

                          Sorry for the long delay in updating. I did install the kit which included everything I needed that was shorted. I immediately get 7 blinks when turned on. I have bypassed the buffers and still 7 blinks. I removed sc 20 and it went to 8 blinks. Then I removed power to the ss board and 7 blinks. This one has me pretty frustrated and about ready to pitch it. I do remember how persistent tw2005 was on one and got his working, but I am at a loss. There are no shorted diodes or igbt's on either board. The ss board led just starts to light and goes off. I dont see anything from the sc led. Voltage seems to go to about 195 and then I hear a faint click and the voltage goes to 205 and then shuts down. Any ideas on what to check. I have fixed about 5 of these boards with success but I am scratching my balding head on this one. Thanks in advance for any input on this, I sure hate to scrap it.

                          Comment

                            #14
                            Re: TC-P55gt31

                            Originally posted by gdawg View Post
                            Sorry for the long delay in updating. I did install the kit which included everything I needed that was shorted. I immediately get 7 blinks when turned on. I have bypassed the buffers and still 7 blinks. I removed sc 20 and it went to 8 blinks. Then I removed power to the ss board and 7 blinks. This one has me pretty frustrated and about ready to pitch it. I do remember how persistent tw2005 was on one and got his working, but I am at a loss. There are no shorted diodes or igbt's on either board. The ss board led just starts to light and goes off. I dont see anything from the sc led. Voltage seems to go to about 195 and then I hear a faint click and the voltage goes to 205 and then shuts down. Any ideas on what to check. I have fixed about 5 of these boards with success but I am scratching my balding head on this one. Thanks in advance for any input on this, I sure hate to scrap it.
                            would seem to suggest something is shorted if the LED on the SC never lights

                            Comment

                              #15
                              Re: TC-P55gt31

                              Thanks tw, I was going to start from scratch and ck everything over again. Sometimes you get blinded by frustration. I will report once I do that, probably this weekend.

                              Comment

                                #16
                                Re: TC-P55gt31

                                Looks like your repair kit is missing the micro sized ic and transistor. That could be responsible for it.

                                ALSO check the power supply secondary fuse. It can fail together with the SC. If they are blown, it could also trigger the 7 blinks code.

                                Comment

                                  #17
                                  Re: TC-P55gt31

                                  Thanks, I am going to start from scratch and check all the boards and follow the tech guide trouble shooting, I will report back. I did replace the driver chip and not quite sure, but I know it was the 531 and I think 501 or 502. I did that along withe the second replacement of some of the igbt's.

                                  Comment

                                    #18
                                    Re: TC-P55gt31

                                    Well, just an update. I got lucky and found a replacement SC board that had been repaired. He had a different code show up so decided to sell off the boards. I got it for $40.00 shipping included and the tv has been up and running for several days. Not sure what happened to the other board, but who cares for $40.00 Thanks everybody for your help, Gary

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