Philips 37MF321D No power no LED

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #21
    Re: Philips 37MF321D No power no LED

    @retiredcaps: OK, that is a good idea, I will do that. Too bad badcaps.net does not have one place for the TIPS&TRICK where people can upload the instructions to it, and sorted and organized by the type of products.
    I am beginning to like this place more than FIXYA. Thanks!
    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

    • alexanna
      Member
      • Mar 2010
      • 1346

      #22
      Re: Philips 37MF321D No power no LED

      I think I am taking the wrong path in troubleshooting this?
      Looking at the flow chart for no power and no led, it is asking to verify voltages on pins 1 and 2 and Pin 3 these are OK.
      There is suppose to be 1.8v on the dim pin #4 and 4.6 v on pin #5 the inverter on off pin.
      If any of these are incorrect its directing me to check the power board.
      The Schematic I posted in my first post is correct for the 37” model.
      I have been beating my head against the wall ,and I just do not see what has to happen for the correct voltage to be on pins 4 and 5
      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

      Comment

      • alexanna
        Member
        • Mar 2010
        • 1346

        #23
        Re: Philips 37MF321D No power no LED

        This is kinda like a double post but there is some stuff added.
        I am hoping someone will look at the troubleshooting flow chart and see if I am interpreting it correctly.
        I am getting the correct voltages on pins 1 through 3,but no voltages on pins 4 and 5.The way I am reading it if any of the voltages are incorrect on pins 1 through 5, it appears they want you to look at the power supply for problems.
        Attached is the link that I believe to be the correct service manual.http://elektrotanya.com/?q=showresul...oria=&kat2=all
        It is the very last manual listed
        Page 90 is the flow chart, and 110 is the schematic for the 37” model.
        Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

        Comment

        • alexanna
          Member
          • Mar 2010
          • 1346

          #24
          Re: Philips 37MF321D No power no LED

          I found an answer to this,4.2v is required on pin 5 of connector 1089 when the power supply is
          Is plugged into the wall socket. Apparently someone removed jumper 9052 on the power supply.
          Anyway with that jumper replaced I do see the standby voltage of 1.3v on pin 9, and the 24v section comes alive.
          I wonder if there is a problem with the panel and the service tech disabled the power supply to try to make the power supply useless?
          Attached Files
          Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

          Comment

          • Jasgriff
            Badcaps Veteran
            • Feb 2012
            • 578
            • UK

            #25
            Re: Philips 37MF321D No power no LED

            Maybe the jumper is there to allow you to check other parts of the board without the inverters getting power? and they forgot to put it back?
            Fixed so far : 1 Home cinema system, 16 LCD Monitors, 4 LCD TV's

            How to resize your pictures guide click HERE
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            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #26
              Re: Philips 37MF321D No power no LED

              If the MOSFET 7071 is not installed, then I can see why you have to have jumper installed, if 7071 is on the board, then it means that the Gate is not getting the signal to turn on 7071 which function as a switch, and the jumper is used to force the 24vdc to come on, that way the tech can tell that the 24vdc is OK but the turn on signal for the 7071 is not functioning. It is like having a relay to turn on the light, but you can jump the replay contact and make the light to come on, then you will know that the relay is not working instead of trying to find out if the lamp is good or not. Same principle as applying voltage to the PS_ON pin to force the power supply to come on, if it does, then the power board is OK but the PS_ON is not coming through from the main board.
              Last edited by budm; 03-16-2012, 06:25 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

              • dustinlof
                New Member
                • Jan 2009
                • 6

                #27
                Re: Philips 37MF321D No power no LED

                I have the same TV with the same symptom, no power, no LED, I however do not have any voltage available to any pin on 1089 as referenced on page 90, I have determined that there is 164.4 VDC across rectifier 6051. And at transformer 5071 pin 1 - 164.2VDC, pin 2 - 163.3VDC pin 3 - 163.4VDC, pin 6 - 163.6VDC and 7 & 8 are at 0v, voltages to 1089 were measured to earth and voltages at transformer were measured to ground(-) at rectifier. I thought at some place in the manual I read there should be 300 some volts at some point in the power board, I cannot however find where I read it and at what point it pertains. Any insight would be greatly appreciated, I do have plenty of electrical knowledge it just applies to automobiles.

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #28
                  Re: Philips 37MF321D No power no LED

                  When you work on the HOT (primary side) side of the power supply, you do not use the chassis as the ground ref point for the voltage measurement, you need to use the Negative leg of the main DC filter cap (the large one with 350~450Vdc rating), that is the circuit ground ref point for the primary circuits. The cold side circuit ground ref is commonly tied to the chassis.
                  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

                  • dustinlof
                    New Member
                    • Jan 2009
                    • 6

                    #29
                    Re: Philips 37MF321D No power no LED

                    Yes, that's what I was referring to as ground(-), I maybe should have referenced to it as negative.

                    Comment

                    • alexanna
                      Member
                      • Mar 2010
                      • 1346

                      #30
                      Re: Philips 37MF321D No power no LED

                      You might want to look at the SMPS start up IC. I haven't looked at the schematic yet this morning but I think it's the 7 pin through hole chip on the hot side of the PS.If you look up the data sheet it will give you minimum voltages for it to start. The small start up cap is critical also.
                      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                      Comment

                      • dustinlof
                        New Member
                        • Jan 2009
                        • 6

                        #31
                        Re: Philips 37MF321D No power no LED

                        at the smps I have on pin 1 Vcc - 186mvdc, pin 2 gnd - 0v, pin 3 ctl - 0v, pin 4 - dem 28mvdc, pin 5 isense - 0v, 6 driver 180mvdc, 8 drain - 158.7vdc. If I am reading the data sheet correctly I should have 1 - 1.5vdc on pin 3 ctl. I am not sure what cap you mean when you say small start up cap.

                        Comment

                        • alexanna
                          Member
                          • Mar 2010
                          • 1346

                          #32
                          Re: Philips 37MF321D No power no LED

                          Originally posted by dustinlof
                          at the smps I have on pin 1 Vcc - 186mvdc, pin 2 gnd - 0v, pin 3 ctl - 0v, pin 4 - dem 28mvdc, pin 5 isense - 0v, 6 driver 180mvdc, 8 drain - 158.7vdc. If I am reading the data sheet correctly I should have 1 - 1.5vdc on pin 3 ctl. I am not sure what cap you mean when you say small start up cap.
                          I spoke to soon on suggesting to check the SMPS,If I am reading the schematic correctly we should try to find out why there is no 24A voltage. I think that is the voltage that is always on when the set is plugged in.
                          Honestly this is over my head; hopefully someone else will jump in and help
                          Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                          Comment

                          • budm
                            Badcaps Legend
                            • Feb 2010
                            • 40746
                            • USA

                            #33
                            Re: Philips 37MF321D No power no LED

                            I am confused, are we talking about troubleshooting alexanna's TV or dustlinlof'sTV.
                            If the (alexanna's TV) PFC Voltage boost circuits are not working then the 24vdc will not be fucnctioning, as stated in post #2.
                            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

                            • dustinlof
                              New Member
                              • Jan 2009
                              • 6

                              #34
                              Re: Philips 37MF321D No power no LED

                              Originally posted by budm
                              I am confused, are we talking about troubleshooting alexanna's TV or dustlinlof'sTV.
                              we were talking about my TV

                              Comment

                              • dustinlof
                                New Member
                                • Jan 2009
                                • 6

                                #35
                                Re: Philips 37MF321D No power no LED

                                Originally posted by alexanna
                                I spoke to soon on suggesting to check the SMPS,If I am reading the schematic correctly we should try to find out why there is no 24A voltage. I think that is the voltage that is always on when the set is plugged in.
                                Honestly this is over my head; hopefully someone else will jump in and help
                                I would assume I would need to see some sort of output voltage on transformer 5071 before the 24A voltage can be present?

                                I just printed this schematic out on 4 sheets of paper and taped them all together to hopefully help me understand this better.

                                Comment

                                • Horty24
                                  Senior Member
                                  • Oct 2011
                                  • 54

                                  #36
                                  Re: Philips 37MF321D No power no LED

                                  Originally posted by alexanna
                                  I found an answer to this,4.2v is required on pin 5 of connector 1089 when the power supply is
                                  Is plugged into the wall socket. Apparently someone removed jumper 9052 on the power supply.
                                  Anyway with that jumper replaced I do see the standby voltage of 1.3v on pin 9, and the 24v section comes alive.
                                  I wonder if there is a problem with the panel and the service tech disabled the power supply to try to make the power supply useless?
                                  I too do not have voltage on pin 4 and 5. I don't believe there needs to be a jumper at 9052. All my caps do look good but I know just because they look good does not mean they are. One thing I do find odd looking at my PS board is solder built up on these pins. Look normal?
                                  Attached Files

                                  Comment

                                  • Horty24
                                    Senior Member
                                    • Oct 2011
                                    • 54

                                    #37
                                    Re: Philips 37MF321D No power no LED

                                    Here are some pics of the PS.
                                    Attached Files

                                    Comment

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