Philips 37PF7321/98 cannot turn on

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  • selldoor
    Slow Learner
    • Dec 2010
    • 7870

    #121
    Re: Philips 37PF7321/98 cannot turn on

    Thats a fine picture! you can dream of more testing tomorrow. Now we can see there will be lots - perhaps start with the diode near the legs of the mosfet just above the "K"
    Good night.

    Last edited by selldoor; 06-18-2014, 09:44 AM.
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment

    • selldoor
      Slow Learner
      • Dec 2010
      • 7870

      #122
      Re: Philips 37PF7321/98 cannot turn on

      Going back to budms post re resistor 3318 Whilst the resistance is ok can you check out
      the soldering on it. Another thread has flagged it up as a problem area so may be worth a look.
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

      Comment

      • bammbammfran
        Badcaps Veteran
        • Apr 2014
        • 476
        • USA

        #123
        Re: Philips 37PF7321/98 cannot turn on

        Originally posted by selldoor
        Going back to budms post re resistor 3318 Whilst the resistance is ok can you check out
        the soldering on it. Another thread has flagged it up as a problem area so may be worth a look.
        I do not think that 3318 on the power supply is a factor right now since we can get the power supply to turn on and give us stable voltages out at the dc side

        Comment

        • selldoor
          Slow Learner
          • Dec 2010
          • 7870

          #124
          Re: Philips 37PF7321/98 cannot turn on

          Originally posted by bammbammfran
          I do not think that 3318 on the power supply is a factor right now since we can get the power supply to turn on and give us stable voltages out at the dc side
          Ok - I thought I read that it was significant in getting the backlights on.
          Please upload pictures using attachment function when ask for help on the repair
          http://www.badcaps.net/forum/showthread.php?t=39740

          Comment

          • john_doe
            Senior Member
            • Apr 2013
            • 192
            • Malaysia

            #125
            Re: Philips 37PF7321/98 cannot turn on

            Originally posted by selldoor
            Thats a fine picture! you can dream of more testing tomorrow. Now we can see there will be lots - perhaps start with the diode near the legs of the mosfet just above the "K"
            Good night.
            I have checked the zener diode 6531. There is 0.7v in the direction of pin 3 to pin 1 of mosfet 7531. I am measuring in-circuit, don't know is it correct. The opposite direction is OL. Looks like 6531 is ok.

            Comment

            • bammbammfran
              Badcaps Veteran
              • Apr 2014
              • 476
              • USA

              #126
              Re: Philips 37PF7321/98 cannot turn on

              more to check on this non switching issue

              we know red Gnd is ok ground
              can you check the other 5 red circle for ground or not ground

              recheck 5v ok at the transistor yellow D
              and double check to make sure 5v is still not on the yellow S pin
              also check for possible voltage to the yellow G pin and yellow B pin at the smaller transistor and small blue circle at the top of the picture

              and , if I could get another pretty picture like this from the top of this area to and including the 11 and 10 pin connectors, that may become useful

              Comment

              • selldoor
                Slow Learner
                • Dec 2010
                • 7870

                #127
                Re: Philips 37PF7321/98 cannot turn on

                ^^^^^^ Picture to go with this?^^^^^^^^
                Please upload pictures using attachment function when ask for help on the repair
                http://www.badcaps.net/forum/showthread.php?t=39740

                Comment

                • bammbammfran
                  Badcaps Veteran
                  • Apr 2014
                  • 476
                  • USA

                  #128
                  Re: Philips 37PF7321/98 cannot turn on

                  What, no x-ray vision !!??

                  john is probably in bed right now having dreams of this thing !!
                  Attached Files
                  Last edited by bammbammfran; 06-19-2014, 01:15 PM.

                  Comment

                  • john_doe
                    Senior Member
                    • Apr 2013
                    • 192
                    • Malaysia

                    #129
                    Re: Philips 37PF7321/98 cannot turn on

                    Originally posted by bammbammfran
                    more to check on this non switching issue

                    we know red Gnd is ok ground
                    can you check the other 5 red circle for ground or not ground

                    recheck 5v ok at the transistor yellow D
                    and double check to make sure 5v is still not on the yellow S pin
                    also check for possible voltage to the yellow G pin and yellow B pin at the smaller transistor and small blue circle at the top of the picture

                    and , if I could get another pretty picture like this from the top of this area to and including the 11 and 10 pin connectors, that may become useful
                    Red circle 1 and 3 are 5v
                    Pin 2 of 1305 is 5v, all3 pins of 1305 are 5v
                    Red circle 4 and 5 are 0v

                    Yellow D is 5v. Yellow S is 0v. Yellow G is 0v. Yellow B and E are 0v. Yellow C is 5v. Blue small circle is 0v.
                    Attached Files

                    Comment

                    • bammbammfran
                      Badcaps Veteran
                      • Apr 2014
                      • 476
                      • USA

                      #130
                      Re: Philips 37PF7321/98 cannot turn on

                      all 3 pins on 1305 is 5 volts !!
                      Well that doesn't right
                      we should have a 5v and a ground
                      do you have the 3 pin wire to the power supply connected ?

                      I also need to know if any of the zero voltage ones grounded
                      turn off power
                      and check them with the ohm setting

                      Comment

                      • john_doe
                        Senior Member
                        • Apr 2013
                        • 192
                        • Malaysia

                        #131
                        Re: Philips 37PF7321/98 cannot turn on

                        Originally posted by bammbammfran
                        all 3 pins on 1305 is 5 volts !!
                        Well that doesn't right
                        we should have a 5v and a ground
                        do you have the 3 pin wire to the power supply connected ?

                        I also need to know if any of the zero voltage ones grounded
                        turn off power
                        and check them with the ohm setting
                        Yes, 3 pin wire 1305 is connected to the power supply board.

                        Red circle 4 and yellow E are ground.
                        Last edited by john_doe; 06-20-2014, 06:59 AM.

                        Comment

                        • bammbammfran
                          Badcaps Veteran
                          • Apr 2014
                          • 476
                          • USA

                          #132
                          Re: Philips 37PF7321/98 cannot turn on

                          Originally posted by john_doe
                          Yes, 3 pin wire 1305 is connected to the power supply board.

                          Red circle 4 and yellow E are ground.
                          disconnect the 3 pin wire and recheck those 3 pins for dc and ground

                          Comment

                          • john_doe
                            Senior Member
                            • Apr 2013
                            • 192
                            • Malaysia

                            #133
                            Re: Philips 37PF7321/98 cannot turn on

                            Originally posted by bammbammfran
                            disconnect the 3 pin wire and recheck those 3 pins for dc and ground
                            None is ground.

                            When I power up with 1305 disconnected, all 3 pins are still 5v.

                            Comment

                            • bammbammfran
                              Badcaps Veteran
                              • Apr 2014
                              • 476
                              • USA

                              #134
                              Re: Philips 37PF7321/98 cannot turn on

                              well, I am lost
                              I have no idea how 5 volts is magically showing up on pin 3 of the 1305 connector with no wire attached and since the transistor pins at the yellow B pin shows no voltage and the yellow E is a ground

                              Comment

                              • selldoor
                                Slow Learner
                                • Dec 2010
                                • 7870

                                #135
                                Re: Philips 37PF7321/98 cannot turn on

                                Well I will keep you company
                                Right ive already admitted I know very little about tvs in general and dont understand this one at all so I just want to throw in this idea, but am happy for it to be shot down in flames. I think we have been looking at the relay as something to switch on the 240v line ( for the inverter section?). I am now wondering if it is part of the protection
                                (see labels on the block diagram by 1305) So if something is tripping the protection ( By the way have you tried it with the lamps connected - if not that could be a "fault") then perhaps that 5v keeps it switched off.
                                Ill leave that in but will flame myself as im sure you have tried to fire it up with the connector to the relay unplugged.

                                Also note the label on the block diagram that says Standby --- Low = ON High =OFF
                                ( I have no real idea what that means unless it means you have to pull pson to low to get it to switch on.)
                                Please upload pictures using attachment function when ask for help on the repair
                                http://www.badcaps.net/forum/showthread.php?t=39740

                                Comment

                                • bammbammfran
                                  Badcaps Veteran
                                  • Apr 2014
                                  • 476
                                  • USA

                                  #136
                                  Re: Philips 37PF7321/98 cannot turn on

                                  even if we need to pull , say pin 3 5volt to ground which could be possibly done with the small transistor that is to the left of it -- Where the hell is that 5 on that pin coming from in he first place ??
                                  if he had the wire connected to the power supply, then it could be coming through the relays coil, but that wire is disconnected !

                                  Comment

                                  • john_doe
                                    Senior Member
                                    • Apr 2013
                                    • 192
                                    • Malaysia

                                    #137
                                    Re: Philips 37PF7321/98 cannot turn on

                                    Originally posted by bammbammfran
                                    even if we need to pull , say pin 3 5volt to ground which could be possibly done with the small transistor that is to the left of it -- Where the hell is that 5 on that pin coming from in he first place ??
                                    if he had the wire connected to the power supply, then it could be coming through the relays coil, but that wire is disconnected !
                                    Bammbammfran - if you want to call it quit, I will understand. You have already spent many hrs/days on my problem.

                                    Comment

                                    • john_doe
                                      Senior Member
                                      • Apr 2013
                                      • 192
                                      • Malaysia

                                      #138
                                      Re: Philips 37PF7321/98 cannot turn on

                                      Originally posted by selldoor
                                      Well I will keep you company
                                      Right ive already admitted I know very little about tvs in general and dont understand this one at all so I just want to throw in this idea, but am happy for it to be shot down in flames. I think we have been looking at the relay as something to switch on the 240v line ( for the inverter section?). I am now wondering if it is part of the protection
                                      (see labels on the block diagram by 1305) So if something is tripping the protection ( By the way have you tried it with the lamps connected - if not that could be a "fault") then perhaps that 5v keeps it switched off.
                                      Ill leave that in but will flame myself as im sure you have tried to fire it up with the connector to the relay unplugged.

                                      Also note the label on the block diagram that says Standby --- Low = ON High =OFF
                                      ( I have no real idea what that means unless it means you have to pull pson to low to get it to switch on.)
                                      What do you mean by 'lamp connected'? Which lamp?

                                      Comment

                                      • bammbammfran
                                        Badcaps Veteran
                                        • Apr 2014
                                        • 476
                                        • USA

                                        #139
                                        Re: Philips 37PF7321/98 cannot turn on

                                        he means the wires from the power supply to the inverter board that lights the bulbs of the screen.
                                        That board is still buried in your first pictures.


                                        What I think we need is power to get to the Gate (yellow G) of the larger transistor

                                        At this point, if it were my board, I would jump a ground line to that Gate and see what happens to the source (Yellow S) voltage wise and if nothing, I would then jump voltage to that pin

                                        then IF the source activated, it should activate the smaller transistor and cause the number 3 pin to ground and if it does that then the relay should turn on

                                        that is providing both transistors are good
                                        and nothing goes POOF !!

                                        Comment

                                        • john_doe
                                          Senior Member
                                          • Apr 2013
                                          • 192
                                          • Malaysia

                                          #140
                                          Re: Philips 37PF7321/98 cannot turn on

                                          Originally posted by bammbammfran
                                          he means the wires from the power supply to the inverter board that lights the bulbs of the screen.
                                          That board is still buried in your first pictures.


                                          What I think we need is power to get to the Gate (yellow G) of the larger transistor

                                          At this point, if it were my board, I would jump a ground line to that Gate and see what happens to the source (Yellow S) voltage wise and if nothing, I would then jump voltage to that pin

                                          then IF the source activated, it should activate the smaller transistor and cause the number 3 pin to ground and if it does that then the relay should turn on

                                          that is providing both transistors are good
                                          and nothing goes POOF !!
                                          What is happening???

                                          I jump a ground to Gate and now the Gate is 20v and Yellow S(source) is 5v.

                                          And the pin 3 of 1305 is 0v.

                                          When I power off and on the tv, the led light on the front panel is green and stay green. Before this, the led is green and after about 2 sec will turn red.
                                          Last edited by john_doe; 06-20-2014, 09:16 AM.

                                          Comment

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