Smd fuse replacement

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  • audiofreak19
    Badcaps Veteran
    • Apr 2013
    • 556
    • usa

    #1

    Smd fuse replacement

    Ok so I have a smd fuse 3a on a main board I have that needs to be replaced. I don't have any extra ones but I do have a 5a laying around. Would it really be that bad to put the 5a in place of the 3a. Or do I need to order a 3a.
  • paulstef
    Badcaps Veteran
    • Dec 2013
    • 724
    • Canada

    #2
    Re: Smd fuse replacement

    As long as everything works fine you can even put in a 200A fuse. Or a nail. :-)

    I would always avoid replacing them with others having higher current rating.

    Comment

    • audiofreak19
      Badcaps Veteran
      • Apr 2013
      • 556
      • usa

      #3
      Re: Smd fuse replacement

      Haha. I might just do it anyway. I'm hoping it will fix the problem w/ the main board.

      Comment

      • Thomas Capper
        Member
        • May 2013
        • 19
        • usa

        #4
        Re: Smd fuse replacement

        I have seen various warnings in tv's, home electricity, and car fuses that you should always replace the fuse with the same type/amperage.

        Comment

        • paulstef
          Badcaps Veteran
          • Dec 2013
          • 724
          • Canada

          #5
          Re: Smd fuse replacement

          Originally posted by audiofreak19
          Haha. I might just do it anyway. I'm hoping it will fix the problem w/ the main board.
          Ah, ok, you still have a problem with the board? In that case do not replace it with a fuse with a higher current rating. It gets damaged for a reason. You may end up damaging traces if you pass too much current through them.

          Comment

          • audiofreak19
            Badcaps Veteran
            • Apr 2013
            • 556
            • usa

            #6
            Re: Smd fuse replacement

            Yea it still didn't fix the problem. I'm almost completely exhausted on this tv. I checked all fuses for voltage. All caps good. All points on power board getting correct voltage. I have no idea where to go one this one. The heat shield on the main board still gets kinda warm. Not so warm it burns but enough to notice. The tv is a m550nv vizio that when plugged it logo flashes for a while then goes to stand by. U turn it on and the backlight turns on but no picture on screen. If u hit the power button to turn on menu the screen dims but no image.

            Comment

            • paulstef
              Badcaps Veteran
              • Dec 2013
              • 724
              • Canada

              #7
              Re: Smd fuse replacement

              Ok, so something draws too much current. You don't happen to have access to infrared camera?

              Comment

              • audiofreak19
                Badcaps Veteran
                • Apr 2013
                • 556
                • usa

                #8
                Re: Smd fuse replacement

                No I don't. Left it in my other spy bag. Lol jk. But originally I had to replace a melted capacitor that was underneath side of the main board next to where the heat shield would be.

                Comment

                • paulstef
                  Badcaps Veteran
                  • Dec 2013
                  • 724
                  • Canada

                  #9
                  Re: Smd fuse replacement

                  Do you have the service manual, schematic? Do you have an oscilloscope?

                  Comment

                  • audiofreak19
                    Badcaps Veteran
                    • Apr 2013
                    • 556
                    • usa

                    #10
                    Re: Smd fuse replacement

                    I dot think they have a service manual for it. And I only have a dmm

                    Comment

                    • paulstef
                      Badcaps Veteran
                      • Dec 2013
                      • 724
                      • Canada

                      #11
                      Re: Smd fuse replacement

                      Can you post a pic of the region where u said you replaced a melted cap?

                      Comment

                      • audiofreak19
                        Badcaps Veteran
                        • Apr 2013
                        • 556
                        • usa

                        #12
                        Re: Smd fuse replacement

                        K
                        Attached Files

                        Comment

                        • audiofreak19
                          Badcaps Veteran
                          • Apr 2013
                          • 556
                          • usa

                          #13
                          Re: Smd fuse replacement

                          Here's another
                          Attached Files

                          Comment

                          • audiofreak19
                            Badcaps Veteran
                            • Apr 2013
                            • 556
                            • usa

                            #14
                            Re: Smd fuse replacement

                            This was before I replaced the smd cap
                            Attached Files

                            Comment

                            • paulstef
                              Badcaps Veteran
                              • Dec 2013
                              • 724
                              • Canada

                              #15
                              Re: Smd fuse replacement

                              Originally posted by audiofreak19
                              This was before I replaced the smd cap
                              So somebody already tried to repair the set before you did?

                              It doesn't look "melted". Was it shorted? What is it connected to? VCC GND etc?

                              Comment

                              • audiofreak19
                                Badcaps Veteran
                                • Apr 2013
                                • 556
                                • usa

                                #16
                                Re: Smd fuse replacement

                                I don't know what it was connected to but the last picture showed the plastic part melted down. So I replaced it but did a real bad solder job.

                                Comment

                                • paulstef
                                  Badcaps Veteran
                                  • Dec 2013
                                  • 724
                                  • Canada

                                  #17
                                  Re: Smd fuse replacement

                                  The cap on the last picture has very likely not been mounted like this in factory. Somebody replaced it already. Was it shorted?

                                  You can determine what it is connected to when you follow the traces back to the power supply. I assume it to be on GND on one side and on 3V3 or %V on the other side.

                                  Comment

                                  • audiofreak19
                                    Badcaps Veteran
                                    • Apr 2013
                                    • 556
                                    • usa

                                    #18
                                    Re: Smd fuse replacement

                                    I wasn't sure. I don't have the board infront of me right now. Before I replaced the cap the tv wouldn't even power on or have the logo light up. And after I replaced it it will turn on but no image.

                                    Comment

                                    • paulstef
                                      Badcaps Veteran
                                      • Dec 2013
                                      • 724
                                      • Canada

                                      #19
                                      Re: Smd fuse replacement

                                      Measure the voltage on that cap. Multimeter first DC, then AC. Post the results.
                                      If possible get a scope borrowed from someone.

                                      Comment

                                      • audiofreak19
                                        Badcaps Veteran
                                        • Apr 2013
                                        • 556
                                        • usa

                                        #20
                                        Re: Smd fuse replacement

                                        K

                                        Comment

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