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Philips 47PFL4606 No Power Fuse Keeps Blowing

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    #21
    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

    Hello Budm

    1. On C946 i get 0.7V ?! seems low to me !
    2. Between pin 3 and 4 i get 4,7V
    3. Between pin 1 and 2 i get 0.85V
    4. C943 is 21.32uF and 1.05 ohm
    5. its really an other board and tv !

    Comment


      #22
      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

      Those results don't seem right. C946 is connected to the Opto isolator (IC907) which has 4.7V across it. It can only get that voltage from D916/C916 which you say is at 0.7V
      Willing to help but I'm no expert.

      Comment


        #23
        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

        The voltage across D916 is 0.7v and C916 0.3V

        Comment


          #24
          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

          The voltage on Pin 3 (Control) of the TOP264 should rise to 5.8V. The capacitor connected to this pin is charged up by the voltage on pin 6 (Drain). When it reaches 5.8V the internal circuit providing the charging current from the Drain supply to the capacitor switches off and the voltage across the capacitor connected to Pin 3 is then maintained by the feedback winding of T904

          Can you check that the voltage on Pin 3 rises to 5.8V
          Last edited by dick_barton; 07-25-2020, 03:52 AM.
          Willing to help but I'm no expert.

          Comment


            #25
            Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

            The voltage on pin 3 rises to 5.5V of TOP264 !
            No difference when 1k resistor in place
            Last edited by trunks81; 07-25-2020, 12:18 PM.

            Comment


              #26
              Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

              So at switch on it rises to 5.5V and stays at that voltage?

              The data sheet says the initial operating voltage needs to reach 5.8V on the Control pin before the mosfet kicks in and drive the transformer so long as the Control voltage doesn't drop below 4.8.V
              Willing to help but I'm no expert.

              Comment


                #27
                Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                "When i measure the 5V its only 2.7V, When i connect an 1K to S/B-5V iam getting 1.9V on the 5V"
                I am confused as to why you are getting Voltage on the cold side of the 5VSTBY power supply but you report this in post #21 "1. On C946 i get 0.7V ?! seems low to me !". C946 which is the filter cap for the rectifier D916 which rectifies the AC from the AUX winding of the STBY transformer T904, having 0.7V on that filter cap means the transformer AUX winding is bad or R959 (4R7 Ohms) is open. The Voltage on that C946 should be around 15V (see your thread of the same TV on another thread) when PS-ON is present, and lower when PS-ON is not present. If you look at the other thread, you will see that you will have around 4.6V output on the 5VSTBY pin, then it will jump up to 5V when PS-ON is present.
                The 15V ON C946 is used for runninng the SMPS ic's and PFC IC

                BTW, post 22 by dick_barton
                "Those results don't seem right. C946 is connected to the Opto isolator (IC907) which has 4.7V across it. It can only get that voltage from D916/C916 which you say is at 0.7V"
                I think he means C946.

                Bottom line, you need to check the Voltage on C946 again.
                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


                  #28
                  Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                  Hello

                  C946 = still reads 0.75V,
                  T904 = Measured along with the 37inch board and reads the same!
                  R953 = 100 ohm
                  C952 = 100.2 nf
                  R956 ,R954 ,R957 ,Q908 ,R952 = Compared them with an other board and they both read the same

                  Comment


                    #29
                    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                    Originally posted by trunks81 View Post
                    Hello

                    C946 = still reads 0.75V,
                    T904 = Measured along with the 37inch board and reads the same!
                    R953 = 100 ohm
                    C952 = 100.2 nf
                    R956 ,R954 ,R957 ,Q908 ,R952 = Compared them with an other board and they both read the same
                    37"?
                    We worked on the 47" same model on this Thread: https://www.badcaps.net/forum/showthread.php?t=85971
                    Last edited by budm; 07-25-2020, 11:07 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


                      #30
                      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                      Hello

                      I have two 47 inch and one 37 inch, The fixed 47 inch is gone now,
                      And the 37inch board is almost exact the same as the 47 inch except for the CCFL part
                      So i did compare it with that board. Also the 47inch tv starts with the 37inch board only no BL

                      Comment


                        #31
                        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                        Where is the link to show me the power supply board of the 37"?
                        This one, correct?
                        https://www.badcaps.net/forum/showthread.php?t=85509
                        That 37" board is still not fixed, correct?
                        That 37" board standby power supply is working, correct? So what Voltage do you have on C946 (no need to use resistor to turn on the power supply), just power up the board by itself.
                        Last edited by budm; 07-26-2020, 12:48 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


                          #32
                          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                          On that board i have 8,1V on C946,
                          also
                          The voltage on pin 3 rises to 5.9V of TOP264 !
                          No difference when 1k resistor in place

                          Comment


                            #33
                            Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                            If you have twp identical boards, one working and one not working perhaps you could give the voltage readings of each around IC905, IC907 & C946/D146 junction.

                            Also can you use your meter set to ohms to compare resistance readings against each other at the above points.
                            Willing to help but I'm no expert.

                            Comment


                              #34
                              Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                              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
                              Last edited by trunks81; 07-27-2020, 10:21 AM.

                              Comment


                                #35
                                Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                IC905 Pin2 is 13V or 1.3V for the working board???

                                Looking through threads on this power supply and the problem tends to be either IC905 or ZD907.
                                Last edited by dick_barton; 07-27-2020, 09:28 AM.
                                Willing to help but I'm no expert.

                                Comment


                                  #36
                                  Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                  Originally posted by dick_barton View Post
                                  IC905 Pin2 is 13V or 1.3V for the working board???

                                  Looking through threads on this power supply and the problem tends to be either IC905 or ZD907.
                                  Sorry Typo its is 1.3V

                                  Changed IC905 and ZD907 and still the same results

                                  Comment


                                    #37
                                    Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                    The voltages for IC905 are not too dissimilar to your test board. They will be for the Opt since there is no 5V on the secondary.

                                    Check the solder joints on IC905 since I feel that this is where the fault lies.

                                    Can you measure the resistance to hot ground of all the pins of IC905 between the good/bad board, power off.
                                    Willing to help but I'm no expert.

                                    Comment


                                      #38
                                      Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                      Got the next

                                      IC905 to hot ground both boards measure almost the same

                                      1 = 9.595k 1 = 9.677k
                                      2 = 10.346k 2 = 10.416k
                                      3 = 6.620k 3 = 6.744k
                                      4 = 0.11ohm 4 = 0.10ohm
                                      5 = 2.7271k 5 = 2.7436k

                                      Comment


                                        #39
                                        Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                        Other than changing IC905 once more I can't see what else there is to check.
                                        You have definately checked R959 and replaced D907 with a 9.1V zener diode.
                                        One side of R959 to hot ground should measure 4.7 ohms (plus winding resistance) and the other side of R959 should measure just the winding resistance. This will eliminate the transformer winding as a problem.

                                        Was IC905 replacement a new device, Chinese purchase or from a donar board?
                                        Last edited by dick_barton; 07-27-2020, 12:06 PM.
                                        Willing to help but I'm no expert.

                                        Comment


                                          #40
                                          Re: Philips 47PFL4606 No Power Fuse Keeps Blowing

                                          Hello,

                                          IC905 was an new unit.. which came from ebay, So probably from china ?
                                          https://www.ebay.com/itm/3pcs-T0P264...53.m2749.l2649

                                          When i measure R959 on both boards iam getting on one side 5.11ohm and the other side 0.15ohm

                                          Ordered the TOP264 at farnell (Sinuss) now and ill see if that fix the problem

                                          EDit used the top264 form the working board and no difference
                                          Last edited by trunks81; 07-27-2020, 01:03 PM.

                                          Comment

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