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Philips 47PFL4606 No Power Fuse Keeps Blowing

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    #41
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Those readings as in all the readings given today do not show any obvious fault.
    I have to bow out at this point since with all the checks made the fault has still not been found.
    Perhaps others can spot something I've mssed.
    Willing to help but I'm no expert.

    Comment


      #42
      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

      Originally posted by trunks81 View Post
      Hello

      Tested the two boards across. and came to the next result
      Color green is for working board and red for the not working
      All is tested without the 1K resistor

      IC905
      1= 2.85V 1.30V
      2= 1.3V 1.26V
      3= 5.92V 5.5V
      4= 0V 0V
      -
      5= 317V 315V

      IC907

      1-2 = 1.10V 0.31V
      3-4 = 2.21V 4.80V


      C946 = 8.16V 0.70V
      D916 = 8.22V 0.70V
      What Voltage do you have on pin 3 and pin 4 of IC907 with ref to negative leg of C946?
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

      Comment


        #43
        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

        1) Check resistance of R965 (2M2 Ohms), it is located around IC 905.
        2) Check the Voltage between the Emitter and Collector of Q913, it is also located around IC 905.
        Never stop learning
        Basic LCD TV and Monitor troubleshooting guides.
        http://www.badcaps.net/forum/showthr...956#post305956

        Voltage Regulator (LDO) testing:
        http://www.badcaps.net/forum/showthr...999#post300999

        Inverter testing using old CFL:
        http://www.badcaps.net/forum/showthr...er+testing+cfl

        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
        http://s807.photobucket.com/user/budm/library/

        TV Factory reset codes listing:
        http://www.badcaps.net/forum/showthread.php?t=24809

        Comment


          #44
          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

          V on pin 3/4 to ground of C946 is 5.50V and 0V,
          V between C/E of Q913 is 0.54V

          on the good board this is

          V on pin 3/4 to ground of C946 is 5.88V and 0V,
          V between C/E of Q913 is 0.55V

          R965 and ZD912 are not on the board

          Comment


            #45
            Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

            Originally posted by trunks81 View Post
            V on pin 3/4 to ground of C946 is 5.50V and 0V,
            V between C/E of Q913 is 0.54V

            on the good board this is

            V on pin 3/4 to ground of C946 is 5.88V and 0V,
            V between C/E of Q913 is 0.55V

            R965 and ZD912 are not on the board
            Your post #24 for C946 Voltage readings:
            C946 = 8.16V (good bd.) 0.70V (bad board)
            D916 = 8.22V 0.70V

            If you look at the schematic, the OPTO IC907 pin 4 (Collector) is connected to the positive leg of C946, so I cannot see how you can have 0V (on good and bad board) on pin 4 of the OPTO IC907. Does that make sense to you?
            Are you sure you are probing at the correct parts on the board?
            It seems to me we are having some kind of measurement error here that is throwing us off trying to troubleshoot the problem.
            Attached Files
            Never stop learning
            Basic LCD TV and Monitor troubleshooting guides.
            http://www.badcaps.net/forum/showthr...956#post305956

            Voltage Regulator (LDO) testing:
            http://www.badcaps.net/forum/showthr...999#post300999

            Inverter testing using old CFL:
            http://www.badcaps.net/forum/showthr...er+testing+cfl

            Tear down pictures : Hit the ">" Show Albums and stories" on the left side
            http://s807.photobucket.com/user/budm/library/

            TV Factory reset codes listing:
            http://www.badcaps.net/forum/showthread.php?t=24809

            Comment


              #46
              Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

              Hello

              V between pin 3/4 on IC907 = 4.74V
              V between pin 4 IC907 / Hot ground = 0.75V
              V between pin 3 IC907 / Hot ground = 5.54V

              V Between + /- C946 = 0.75V
              V between + C946 and hot ground = 0.75V


              On the good board this is

              V between pin 3/4 on IC907 = 2.23V
              V between pin 4 IC907 / Hot ground = 8.14V
              V between pin 3 IC907 / Hot ground = 5.90V

              V Between + /- C946 = 8.1V
              V between + C946 and hot ground = 8.1V
              Last edited by trunks81; 07-28-2020, 12:28 AM.

              Comment


                #47
                Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                Post 34:
                Ic905 good bd / bad bd
                1= 2.85v /1.30v
                2= 1.3v / 1.26v
                3 (C) = 5.92v / 5.5v
                4= 0v / 0v

                Your post 46 now makes sense.

                At this point, it seems to me that the Voltage on pin 3 (C) never reach 5.8V for SMSP TOP IC to start running.
                One thing that can load down pin 3 (C) is Q906 (PNP) turned on by the brown out detection circuit, or it has leakage between E and C.

                You can try removing R966 (330K) so the Q906 cannot be bias on, this will disable the brown out protection circuit to see if the TOP will run or not.
                But if Q906 is leaky, then you will have to remove it.

                You also need to check the Vdrops of ZD909 (9.1V Zener).

                For the the TOP to work, Q906 has to be off, Q913 has to be on, but if brown out occurs, the Q906 will be on which causes Q913 to be off and shut down the TOP SMPS.

                See attached picture regarding to Brown out detection circuit.
                Attached Files
                Last edited by budm; 07-28-2020, 02:16 AM.
                Never stop learning
                Basic LCD TV and Monitor troubleshooting guides.
                http://www.badcaps.net/forum/showthr...956#post305956

                Voltage Regulator (LDO) testing:
                http://www.badcaps.net/forum/showthr...999#post300999

                Inverter testing using old CFL:
                http://www.badcaps.net/forum/showthr...er+testing+cfl

                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                http://s807.photobucket.com/user/budm/library/

                TV Factory reset codes listing:
                http://www.badcaps.net/forum/showthread.php?t=24809

                Comment


                  #48
                  Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                  i removed R966 first still the V is 5.50 in pin 3, So i also removed Q906 same story.
                  ZD909 measure in Diodemode 0.68V and V across it is 4.2v and on the good board is 3.2V

                  Comment


                    #49
                    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                    Originally posted by trunks81 View Post
                    i removed R966 first still the V is 5.50 in pin 3, So i also removed Q906 same story.
                    ZD909 measure in Diodemode 0.68V and V across it is 4.2v and on the good board is 3.2V
                    ZD909 Vdrops is fine.
                    So without R866 and Q906 in place, the E-C Voltage of Q913 is still <1V?
                    Without Q906 in place, I do not see anything else that can load down pin 3, you only have ZD907 (9.1V Zener), C948, R620 in series with C948 connected to pin 3 (C), which you have already tested those parts out.
                    Last edited by budm; 07-28-2020, 02:42 AM.
                    Never stop learning
                    Basic LCD TV and Monitor troubleshooting guides.
                    http://www.badcaps.net/forum/showthr...956#post305956

                    Voltage Regulator (LDO) testing:
                    http://www.badcaps.net/forum/showthr...999#post300999

                    Inverter testing using old CFL:
                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                    http://s807.photobucket.com/user/budm/library/

                    TV Factory reset codes listing:
                    http://www.badcaps.net/forum/showthread.php?t=24809

                    Comment


                      #50
                      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                      it is still 0.55V

                      Comment


                        #51
                        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                        Originally posted by trunks81 View Post
                        it is still 0.55V
                        That transistor is on as it should be.
                        I updated my reply of post 49.
                        Last edited by budm; 07-28-2020, 02:47 AM.
                        Never stop learning
                        Basic LCD TV and Monitor troubleshooting guides.
                        http://www.badcaps.net/forum/showthr...956#post305956

                        Voltage Regulator (LDO) testing:
                        http://www.badcaps.net/forum/showthr...999#post300999

                        Inverter testing using old CFL:
                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                        http://s807.photobucket.com/user/budm/library/

                        TV Factory reset codes listing:
                        http://www.badcaps.net/forum/showthread.php?t=24809

                        Comment


                          #52
                          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                          BTW, so the 5V standby is still low at this point, correct?
                          Never stop learning
                          Basic LCD TV and Monitor troubleshooting guides.
                          http://www.badcaps.net/forum/showthr...956#post305956

                          Voltage Regulator (LDO) testing:
                          http://www.badcaps.net/forum/showthr...999#post300999

                          Inverter testing using old CFL:
                          http://www.badcaps.net/forum/showthr...er+testing+cfl

                          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                          http://s807.photobucket.com/user/budm/library/

                          TV Factory reset codes listing:
                          http://www.badcaps.net/forum/showthread.php?t=24809

                          Comment


                            #53
                            Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                            That is still around 2v to 2,4v

                            Comment


                              #54
                              Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                              I'm clutching at straws here. It may be worthwhile checking any component that you have replaced and make sure that something silly like a diode fitted the wrong way around or a solder bridge to a pad alongside.
                              Willing to help but I'm no expert.

                              Comment


                                #55
                                Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                I just cannot see what else can stop the C Voltage to rise up to 5.8V for the IC to startup, which at the same time I do not expect to see 2V on the cold side if the IC is not running at all but may be running a little bit on and off, something is amiss here on component that are tested good.
                                Right now he needs to leave the brown out detection out and keep the circuit in minimum configuration that the IC requires to run.
                                Last edited by budm; 07-28-2020, 04:06 AM.
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment


                                  #56
                                  Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                  how do i keep the circuit in minimal config ?

                                  Comment


                                    #57
                                    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                    Originally posted by trunks81 View Post
                                    i forgot to check them they where the fault.. smps doesnt blow the fuses any more !

                                    Edit smps stil doesnt has power to the M/B so i swapped out IC901 and IC902
                                    After this R919 exploded and D901,Q902 measure very low ohms (these where replaced by me before !)
                                    Still dont understand why D901 and Q902 and R919 exploded when i replaced IC901/902

                                    Also how do i keep the config in an bare minimum ?

                                    Comment


                                      #58
                                      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                      Checked the total brown out circuit on faults !
                                      everthing measure oke in ohms no strange readings
                                      Attached Files

                                      Comment


                                        #59
                                        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                        1) Leave out R966 and Q906 of the brownout circuit, we do not need them right now for the circuit to function.
                                        2) Remove R947 (4.7R), R965 (2M2).
                                        3) "Still dont understand why D901 and Q902 and R919 exploded when i replaced IC901/902" Something was done wrong or bad parts, but we will deal with that later, right now we need to get the 5V standby working first.
                                        4) I also need high res pictures of the whole bottom side of the board you are working on so I can see the soldering works that were done to the board.
                                        Last edited by budm; 07-28-2020, 03:03 PM.
                                        Never stop learning
                                        Basic LCD TV and Monitor troubleshooting guides.
                                        http://www.badcaps.net/forum/showthr...956#post305956

                                        Voltage Regulator (LDO) testing:
                                        http://www.badcaps.net/forum/showthr...999#post300999

                                        Inverter testing using old CFL:
                                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                        http://s807.photobucket.com/user/budm/library/

                                        TV Factory reset codes listing:
                                        http://www.badcaps.net/forum/showthread.php?t=24809

                                        Comment


                                          #60
                                          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                          Hello Budm

                                          Done al the steps you asked except remove R965 that one isnt on the board. and R866 is R966.
                                          But now i have 5,9volt @pin 3 of ic905 and 4,6v on the 5v
                                          Attached Files
                                          Last edited by trunks81; 07-28-2020, 02:51 PM.

                                          Comment

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