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    Cross reference for B90N08

    Working in Hanns.g monitor HL273 with bad power supply. It appears to have short B90N08 diode. Can someone cross reference the diode since I can't find it to purchase.
    Thanks

    #2
    Re: Cross reference for B90N08

    Originally posted by ned1 View Post
    It appears to have short B90N08 diode.
    Are you sure it's a diode. Can you post a picture?
    Attached Files
    Willing to help but I'm no expert.

    Comment


      #3
      Re: Cross reference for B90N08

      The main fuse also blown? And yes, pictures of what you are working on.
      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


        #4
        Re: Cross reference for B90N08

        I removed diode from board and all 3 leads are short to each other. The main fuse is not blown, all capacitors are ok. During lead lifting I damaged diode so I will need it anyway. I will post pictures shortly.

        Comment


          #5
          Re: Cross reference for B90N08

          Here is the picture
          Attached Files

          Comment


            #6
            Re: Cross reference for B90N08

            I put the diode back for reference of placement on board. You can see damage from removal.
            Attached Files

            Comment


              #7
              Re: Cross reference for B90N08

              A 90N08 should be something like a 90A, 80V Mosfet. However, IF that is shorted, then the fuse should be blown and maybe a few more parts yet, as budm already suggested. Pictures would be nice indeed.

              Never mind me on the pictures....
              Last edited by CapLeaker; 08-24-2016, 04:06 PM.

              Comment


                #8
                Re: Cross reference for B90N08

                Yeah... I can see it. Q2 you are talking about. That's a Mosfet. Trick is to preheat that board first, or having a sodering iron with some "Ooomph".

                Comment


                  #9
                  Re: Cross reference for B90N08

                  You could have removed it by applying plenty of fresh solder on the tab and keeping your soldering iron on it until you can lift it up with tweezers or small nose pliers.
                  Last edited by dick_barton; 08-24-2016, 04:36 PM.
                  Willing to help but I'm no expert.

                  Comment


                    #10
                    Re: Cross reference for B90N08

                    Digikey have some similar logic gate level mosfets eg FDD3570-ND which may be a suitable replacement.
                    Willing to help but I'm no expert.

                    Comment


                      #11
                      Re: Cross reference for B90N08

                      BTW, that power MOSFET is for the Boost converter circuit to step up the Voltage for the LED Backlights.
                      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


                        #12
                        Re: Cross reference for B90N08

                        Thanks

                        Comment


                          #13
                          Re: Cross reference for B90N08

                          So should I follow dick Barton recommendation or I need different one?

                          Comment


                            #14
                            Re: Cross reference for B90N08

                            If that mosfet was short circuit then it may also have damaged U1. I would also check the resistors around U1 are all still the correct value and not damaged.

                            Edit
                            What is the part number written on U1
                            Last edited by dick_barton; 08-25-2016, 03:09 AM.
                            Willing to help but I'm no expert.

                            Comment


                              #15
                              Re: Cross reference for B90N08

                              matter effect, you would have to check the whole gate drive circuit.

                              Comment


                                #16
                                Re: Cross reference for B90N08

                                The marking on U1 Is OB3362HP

                                Comment


                                  #17
                                  Re: Cross reference for B90N08

                                  Received FDD3570-ND and installed. Getting green light on the monitor power button indicator, but still no picture. Any more suggestions.

                                  Comment


                                    #18
                                    Re: Cross reference for B90N08

                                    I would think the OB3362 four string LED driver IC could also be blown, always best to replaced as a pair with mosfet, and check current limiting resistors as Dick suggests

                                    Comment


                                      #19
                                      Re: Cross reference for B90N08

                                      Originally posted by ned1 View Post
                                      Received FDD3570-ND and installed. Getting green light on the monitor power button indicator, but still no picture. Any more suggestions.
                                      What voltages are now missing????
                                      Attached Files
                                      Last edited by dick_barton; 08-30-2016, 07:44 AM.
                                      Willing to help but I'm no expert.

                                      Comment


                                        #20
                                        Re: Cross reference for B90N08

                                        with board removed and plugged to 120V I am getting 5V to both 5V pins to ground in and no voltages on ENA or ADJ pins to ground.

                                        Comment

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