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Philips 47PFL4606H/12 flickering issue/strobo effect

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    #21
    Re: Philips 47PFL4606H/12 flickering issue/strobo effect

    yes, i checked the schematics as well. but definitely the problem is not from there. check edit 2 in the post above
    i think the easiest thing to do would be to buy another PSU. but i can not seem to find any in my country. i found one in poland on some website, but i am not sure if they actually have it. on ebay i could not see any in europe

    i found this forum post
    i removed pin 2 - so this way we have 0V on it. the buzzing is completely gone. according to this forum " If the buzzing fades down at max level - the problem is in loose transformer cores / windings on inverter board..."

    there is no more flicker. i now understand why there was no buzz when booting and displaying the philips logo, because at that time probably the backlight was set to 100% because the motherboard was booting up. once it booted and loaded the settings it started supplying the voltage to the PSU on pin 2. then the buzzing started and the flicker as well. the problem is that this voltage is constant from the motherboard, meaning that the issue is on the PSU. so, what to do next?
    Last edited by tuner2000i; 06-13-2018, 02:55 PM.

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      #22
      Re: Philips 47PFL4606H/12 flickering issue/strobo effect

      so as a resume:
      1. the flicker only appears after the tv boots up ( and probably the motherboard starts supplying voltage on PWM pin ) and disappears after about 30 min of turned on
      2. there is a constant buzzing sound coming from the inverter. when the flicker occurs, the buzzing also fluctuates.
      3. changing the "image presets" affects the flicker somehow, flicker seems stronger on power saver setting - with lower backlight. there is no backlight control option in the settings
      4. removing one of the ccfl connectors from the inverter makes the buzzing sound a lot stronger and the flicker more intense. it happens the same with both of the high voltage cables.
      5. removing the pin 2 wire from the connector which controls the intensity of the backlight removes the buzzing completely and the flicker as well.

      i have started reading more about this issue, so could this be bad ccfl tubes in the end or damaged inverter?
      Last edited by tuner2000i; 06-13-2018, 03:45 PM.

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        #23
        Re: Philips 47PFL4606H/12 flickering issue/strobo effect

        "5. removing the pin 2 wire from the connector which controls the intensity of the backlight removes the buzzing completely and the flicker as well." At this mode, are the backlights on or off?
        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


          #24
          Re: Philips 47PFL4606H/12 flickering issue/strobo effect

          the backlight is ON. as service manual states, 0V on pin 2 means backlight intensity is 100% , for minimum 3,3V is required. no wire = 100% intensity
          The tv works as normal, no flicker at all, no buzzing sound from the inverter.
          Last edited by tuner2000i; 06-13-2018, 06:40 PM.

          Comment


            #25
            Re: Philips 47PFL4606H/12 flickering issue/strobo effect

            Ah, I look at the chart again, it is opposite from most backlights level control.
            Since there is no flicker, to me that sounds like something going on with the PWM signal, you may have to look at it with scope to see if the pulse width is varying or not.
            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


              #26
              Re: Philips 47PFL4606H/12 flickering issue/strobo effect

              Unfortunately I do not have an oscilloscope...
              But the pwm voltage is coming from the motherboard, right? It is doing the same with both motherboards i have
              What do you think of the buzzing sound that was coming from the inverter? Can this affect the issue somehow? That sound was there ever since i bought the tv. It is completely gone after removing the wire.
              Last edited by tuner2000i; 06-14-2018, 04:30 AM.

              Comment


                #27
                Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                I have seen some brand new Westinghouse TV's that will make noise when the backlights are set to <100% from day one.
                This is tough without abling to see the control signal with the scope.
                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 47PFL4606H/12 flickering issue/strobo effect

                  But the pwm voltage is coming from the motherboard towards the PSU, right? So it can’t be that both the motherboards have the same fault. Or is the voltage going ghe other way around? I did not measure it after removing the wire

                  Comment


                    #29
                    Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                    Yes, the main board is the one that send out the PWM signal, if the scope shows good steady Pulse width, then you will have to trace the circuits in the inverter section next.
                    I did not look at the details of the schematic to see if there is an option for Analog dimming control function or not.
                    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 47PFL4606H/12 flickering issue/strobo effect

                      Hello guys,
                      believe it or not, I have (almost) the same problem with a Philips LCD.
                      Today my neighbour called me over, to have a look at his TV. It is making the same buzzing, but luckily, flickering has not occured yet. This sound makes him go crazy, so as I will have time (in 1-2 weeks), I will bring it home and have a look at its insides. At the moment I can't tell any modell numbers or anything, I only saw it is a >40" Philips LCD, as it is mounted on the wall. I will update this thread later, when I opened this baby.
                      Cheers, Janos

                      Comment


                        #31
                        Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                        I have removed the pwm pin2 wire setting the backlight level at 100%. I used the tv like this all summer (only in the weekends) without any issues or flicker. Now it takes a very long time for the backlight to turn on. This happened suddenly and the time seems to increase more and more. At first i had to wait about 5 min, then even over 30 min. Once the backlight is on, everything works good even if i leave the TV on for days. The pwm wire is removed so no flicker. I am trying to search for a replacement power supply but i can not find one anywhere..

                        Comment


                          #32
                          Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                          Hello tuner2000i ~

                          I have a 46” Philips (46PFL3705D/F7) that is behaving much like yours. Not exactly, but about 90% of what you have described in the above thread is the same.

                          Did you find a solution yet?

                          Comment


                            #33
                            Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                            I have replaced the power supply and the TV is working perfectly now

                            Comment


                              #34
                              Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                              That’s good to know. Thanks for the reply. I had the same feeling about mine a few months ago and bought a power supply that turned out not to be viable because it was for a 40” and not the 46” I have. Both had the same primary PSU board # ~ (BA01POF0103 2), but had slightly different secondary #’s (A01P2MPW for the 40” and A01Q2MPW on the 46”).

                              I haven’t been able to find the exact match for the 46” one anywhere, but I’ll keep looking with more confidence now thanks to your post.

                              Please let me know, if you can, if anything changes with your set. I hope it continues to run flawlessly for you.

                              Thanks ~

                              ~ kca

                              Comment


                                #35
                                Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                                The one i found was from a smaller TV. The last letter from the part number was different. E instead of U. It was almost identical but i had to desolder and replace the canle from the Power supply to the board because it was too short. I actually did this 3 days ago, because it took me few months to find a board. Eventually i bought one with 35 euro shipping included and works like a charm. I suspect there was something wrong around or with the invertor. Good luck!

                                Comment


                                  #36
                                  Re: Philips 47PFL4606H/12 flickering issue/strobo effect

                                  It seems like I have the same issue. Its a 46" model, doing the same flickering/buzzing after startup for like 10 mins. What I noticed that the #2 pin (BL DIM) starts at 3.3V then after booting it drops back to 2.6-2.7V that is normal but until then the power supply perfectly quiet and the backlight is not flickering at all. As soon as it drops the show starts. No visible bulging of caps, what do you think guys where should i start tearing it down?

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