Philips 47PFL4606 No Power Fuse Keeps Blowing

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #81
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Originally posted by trunks81
    1. i did place an part from an other donor board.
    2. i did not put back R947 and R966,Q906
    3. Yes iam going to leave it out.
    4. Q907 = 9,8 to 10.5V on all the legs to hot ground
    1) We still want to leave R966, Q906 for the Brownout protection circuit out for now. R947 is not part of the brownout circuit, I had you removed to isolate the standby power supply from the PFC and the 12V/24V circuit.

    2) R947 (4.7 Ohms) is for supplying Voltage to the PFC IC and the 12V/24V SMPS IC, so without having it in place you will have switched 15V Vcc to run those two IC's. You will leave it out for now until we finish checking the parts in the PFC section.

    3) Q907 is used as a switch to provide the switched 15V to run the PFC and 12V/24V SMPS IC'c. It is turned on when 1K pull up resistor is connected. Did you replace Q907 since the old one was shorted?

    4) You need to check R929 (47K) which is connected between Gate and Source pin of PFC MOSFET Q902, we want to make sure it is not damaged.

    5) Did you verify if R916 is 4R7 or not on the good board? That is important, you must verify that.
    Last edited by budm; 07-29-2020, 02:54 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

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #82
      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

      I just read the thread below about the board used in the 37" which is what you say it is the good board?
      https://www.badcaps.net/forum/showth...695#post977695
      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

      • trunks81
        Badcaps Veteran
        • May 2020
        • 265
        • Nederland

        #83
        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

        Q907 is changed and the measurements in previous post where with an 1K in place
        Q907 = 9,8 to 10.5V on all the legs to hot ground

        4. R929 is damaged getting an reading of 28/k ohm and reverse 8.2K ohm
        Soldered R929 out of the pcb and now its reading 47K ohm
        5. R916 reads 123K ohm and reverse 133K ohm !! the bad board reads 4.7 ohm in both directions
        Last edited by trunks81; 07-29-2020, 03:22 PM.

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #84
          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

          Originally posted by trunks81
          Q907 is changed and the measurements in previous post where with an 1K in place
          Q907 = 9,8 to 10.5V on all the legs to hot ground

          4. R929 is damaged getting an reading of 28/k ohm and reverse 8.2K ohm
          Soldered R929 out of the pcb and now its reading 47K ohm

          5. R916 reads 123K ohm and reverse 133K ohm !! the bad board reads 4.7 ohm in both directions
          4) Since R929 reads 47K as it should be then it was not damaged.

          5) R916 is part of the Gate drive circuit for MOSFET Q902, the circuit will not work with that high if the resistance present on the Gate drive circuit OF THE GOOD BOARD. Can I see the picture of the good board and the bad board around the resistor and Q902? Are you sure you good board is good?
          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

          • trunks81
            Badcaps Veteran
            • May 2020
            • 265
            • Nederland

            #85
            Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

            Yes the (good) board (37 inch) is partially working problem now is that the CCFL are flickering but the board gives an 5/12/24V and the tv starts
            Attached Files

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #86
              Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

              Originally posted by trunks81
              Yes the (good) board (37 inch) is partially working problem now is that the CCFL are flickering but the board gives an 5/12/24V and the tv starts
              Both pictures show R916 markings of 4R7, so I do not understand by the reading of the good board is over 100K that you reported "R916 reads 123K ohm and reverse 133K ohm" on the 37" good board.
              Last edited by budm; 07-29-2020, 04:27 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

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #87
                Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                BTW, we still need to find out why we only have about 10V on C946 when 1K pull up is connected, the PFC IC FAN6961 and SMPS ICNCP1271 need 12.5V for the circuit to start running.
                We know that IT should have about 15V based on the board that we fixed for 47" in the link below.
                https://www.badcaps.net/forum/showthread.php?t=86061
                https://www.badcaps.net/forum/attach...6&d=1594984130
                So we need to figure out why we are only getting around 10V.
                Last edited by budm; 07-29-2020, 06:40 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

                • trunks81
                  Badcaps Veteran
                  • May 2020
                  • 265
                  • Nederland

                  #88
                  Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                  Hello Budm

                  My measuments of Q907

                  https://www.badcaps.net/forum/attach...1&d=1596089841
                  Attached Files

                  Comment

                  • budm
                    Badcaps Legend
                    • Feb 2010
                    • 40746
                    • USA

                    #89
                    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                    We know that we have those Voltages at Q907 (or C946), we need to find out why the Voltage generated by the 5VSTBY transformer is so low, it should be closed to 15V like we had in other thread, that is what we need to figure out.
                    Right now 10V to too low to run t he PFC IC and the 12V/24V SMPS IC.
                    If you check the Voltage on your 37", you will see that it is higher than this 47" board we are working on.
                    We know that the 5V output is OK, we have 5V when 1K is connected but we do not have the 15V from AUX winding when 1K is connected, something is loading down this Voltage. We need to get correct Voltage at this section first before working in the PFC and the 12V/24V section.
                    Check the Voltage of Q907 (or C946) on your 37" board with and without 1K and see what you get.
                    Last edited by budm; 07-30-2020, 12:58 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

                    • trunks81
                      Badcaps Veteran
                      • May 2020
                      • 265
                      • Nederland

                      #90
                      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                      C946 = 8.15v / 9.8v (37)
                      c946 = 7.8v / 10.5v (47)
                      Last edited by trunks81; 07-30-2020, 01:08 AM.

                      Comment

                      • trunks81
                        Badcaps Veteran
                        • May 2020
                        • 265
                        • Nederland

                        #91
                        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                        .
                        Last edited by trunks81; 07-30-2020, 01:07 AM.

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #92
                          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                          Originally posted by trunks81
                          C946 = 8.15v / 9.8v (37)
                          c946 = 7.8v / 10.5v (47)
                          The 37: board is actually working with that low Voltages, 9.8V? 9.8 is not enough to run the PFC and the SMPS IC.
                          That does not look right at all.
                          What DC Voltage (measured between the two legs of the cap) do you get on the main filter cap of the 37" board with 1K in place?
                          The picture attached is from your working 47" board.
                          Attached Files
                          Last edited by budm; 07-30-2020, 01:45 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

                          • trunks81
                            Badcaps Veteran
                            • May 2020
                            • 265
                            • Nederland

                            #93
                            Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                            Ive got 311V on Filter cap of the 37 inch with 1K in place. (Strange when i place this board back into the tv ive got 300V on the filtercap and 14,6V on C946 tv is running only backlight is flickering)
                            Also gor 311 on the filter cap of 47 inch
                            Last edited by trunks81; 07-30-2020, 03:25 AM.

                            Comment

                            • ivtec
                              Badcaps Legend
                              • Dec 2008
                              • 1967
                              • USA

                              #94
                              Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                              Originally posted by trunks81
                              Ive got 311V on Filter cap of the 37 inch with 1K in place. (Strange when i place this board back into the tv ive got 300V on the filtercap and 14,6V on C946 tv is running only backlight is flickering)
                              Also gor 311 on the filter cap of 47 inch
                              Flickering maybe bad caps on
                              inverter board.

                              Comment

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA

                                #95
                                Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                Originally posted by trunks81
                                Ive got 311V on Filter cap of the 37 inch with 1K in place. (Strange when i place this board back into the tv ive got 300V on the filtercap and 14,6V on C946 tv is running only backlight is flickering)
                                Also gor 311 on the filter cap of 47 inch
                                That means the PFC Booster circuit is not working on both boards! That 37" board is not fixed.
                                The Voltage on the main filter cap should be around 380 ~ 400V when PFC is working.
                                The schematic shows 395V.
                                The inverter circuit will not work properly at 311V, it should not even come on if it has low Voltage protection circuit.
                                BTW, is your AC Voltage is 230VAC? Measure it.if it is 230VAC, then the Voltage on the cap should be around 325VDC when in standby.
                                BTW, you do know how to read schematic, correct?
                                Last edited by budm; 07-30-2020, 02:59 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

                                • trunks81
                                  Badcaps Veteran
                                  • May 2020
                                  • 265
                                  • Nederland

                                  #96
                                  Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                  Hello Budm

                                  Oke good to know need to find out then what is causing it!
                                  what else can i check ?
                                  What section in the schematics is the PFC Booster circuit ?
                                  Last edited by trunks81; 07-30-2020, 03:01 PM.

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #97
                                    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                    I updated my reply.
                                    The cause of both board not working is due to low voltage on C946.
                                    So the seller of the 37" board sold you bad board.
                                    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

                                    • trunks81
                                      Badcaps Veteran
                                      • May 2020
                                      • 265
                                      • Nederland

                                      #98
                                      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                      That correct it is 230V and when i measure it is 230 exactly
                                      Iam trying to learn how to read schematic i understand a little but still not enough

                                      Comment

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #99
                                        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                        Originally posted by trunks81
                                        That correct it is 230V and when i measure it is 230 exactly
                                        Iam trying to learn how to read schematic i understand a little but still not enough
                                        OK, that explain why you did not understand what Voltage you should get and why.
                                        At this we cannot use the 37" board as a good board since the VCC Voltage is too low to run PFC and the SMPS IC's.
                                        We need to get hat 10V up 15V first but I do not know yet why it is not working when the 5V output is correct at 5V when 1K is present.
                                        So are you going to return that defective 37" board?
                                        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

                                        • trunks81
                                          Badcaps Veteran
                                          • May 2020
                                          • 265
                                          • Nederland

                                          #100
                                          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                          What sections can i check more to find an error in the pfc ?

                                          Comment

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