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Sceptre X322BV-HD - No Power

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    Sceptre X322BV-HD - No Power

    A co-worker found this TV on the curb by his house and pulled it for me. I inspected it and the panel looked undamaged. I plugged it in and it had no signs of power at all. I opened it up and found the classic bulging capacitor issue. I ordered replacements for the bulging caps and replaced them. I plugged it in and, again, no power signs whatsoever (no LED, no "click").

    I searched on this forum and found someone with a similar model who had a similar issue, so I extrapolated mine from theirs and ordered/replaced some more capacitors on the PSU. Tried it again and no dice.

    I'm not getting a click/LED at all, so it must be the 5VDC, but I'm unsure how to proceed in testing it. I have a multimeter (but no car lights), and I looked through the basic troubleshooting guides, but I was unable to discern how to use the DMM to test.

    I've attached a picture of the PSU with all the capacitors I've replaced highlighted. The huge capacitor in the middle and the two at the far side were the only obviously bulging ones. I replaced the others in the middle section after finding the other post about this set (which admittedly had a different symptom).

    How should I best proceed when my persistent issue is no power whatsoever?

    (Note that I can see nothing else obvious inside the TV: no blown fuses, no blackened areas, nothing obvious. I have repaired a few sets in the past and typically replacing the bulging capacitors is enough.)
    Attached Files

    #2
    Re: Sceptre X322BV-HD - No Power

    So you do not even have 5VSB between 5VSB pin and the GND pin when running the power supply by itself? If that is the case then you need to find out if you have 160VDC between the two legs of the main filter cap or not first.
    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


      #3
      Re: Sceptre X322BV-HD - No Power

      So I mounted the PSU and plugged the main power harness into it, but none of the smaller connectors. I put the DMM on the +5 and 5VSB and the GND pins and it read 0. I tried all the pins and they all read 0.

      Which cap is the main filter cap? I tried going across both legs of the huge cap and got 0 there as well.

      Comment


        #4
        Re: Sceptre X322BV-HD - No Power

        The biggest one laying on its side.
        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


          #5
          Re: Sceptre X322BV-HD - No Power

          I put the DMM across both legs and it reads 0. So does this likely mean there is an open circuit somewhere before it?

          Comment


            #6
            Re: Sceptre X322BV-HD - No Power

            Cap on the lower right wasn't bulging... It's just the factory stamping...

            As a rule, look for bulging in the center of the top...
            ASRock B550 PG Velocita

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            32 GB G.Skill RipJaws V F4-3200C16D-32GVR

            Sapphire Nitro+ Radeon RX 6750 XT

            eVGA Supernova G3 750W

            Western Digital Black SN850 1TB NVMe SSD

            Alienware AW3423DWF OLED




            "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

            "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

            "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

            "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

            Comment


              #7
              Re: Sceptre X322BV-HD - No Power

              is it just me as i cant see a mains fuse on that psu?

              Comment


                #8
                Re: Sceptre X322BV-HD - No Power

                Originally posted by RJARRRPCGP View Post
                Cap on the lower right wasn't bulging... It's just the factory stamping...
                The image I attached with the highlighted caps is 100% post replacement. I looked through my photos and the only one I have pre-replacement is one of the big boy which was definitely bulging.

                Comment


                  #9
                  Re: Sceptre X322BV-HD - No Power

                  Originally posted by vinceroger69 View Post
                  is it just me as i cant see a mains fuse on that psu?

                  I don't see one either.
                  Are there LCD TV manufacturers who omit them?

                  Comment


                    #10
                    Re: Sceptre X322BV-HD - No Power

                    But you said no blown fuses in post 1.
                    The fuse is shrink wrapped inside the black shrink tube right next to the AC input connector.
                    If the fuse is blown then you need to check the Bridge rectifier, the PFC MOSFET, the STBY power supply MOSFET, the 12V/24V power supply MOSFETs.
                    Attached Files
                    Last edited by budm; 09-03-2016, 04:06 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


                      #11
                      Re: Sceptre X322BV-HD - No Power

                      Looks like, through ignorance, I've made a liar of myself. I get no continuity through the fuse, and, pulling back the shrinkwrap, it looks blackened inside.

                      Thanks for your patience and persistence. I'll order a new one and replace it and go from there. Pretty foolish of me to replace so many capacitors without doing a thorough troubleshooting first.

                      Comment


                        #12
                        Re: Sceptre X322BV-HD - No Power

                        When the fuse is blackened like that you have really bad shorted out parts on the board that you must check.
                        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


                          #13
                          Re: Sceptre X322BV-HD - No Power

                          Any advice on how to check other parts? Nothing else looks damaged, and the underside of the board isn't blackened either. Could the failing caps have caused a short big enough to blow the fuse?

                          Comment


                            #14
                            Re: Sceptre X322BV-HD - No Power

                            Do you know how to test bridge rectifier, and MOSFETs?
                            Get the P/N as printed on any one of the Power MOSFET, look up the spec sheet to get the pin out, you need to check the RESISTANCE between S (Source) pin and D (Drain) pin to see if it shows <10 Ohms or so, that will be bad MOSFET.
                            Look up the spec sheet of the Bridge rectifier to get the pin out to test the resistance of all 4 Diodes inside the bridge rectifier package for low resistance reading which will indicate bad bridge.
                            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


                              #15
                              Re: Sceptre X322BV-HD - No Power

                              Originally posted by dmanthei View Post
                              The image I attached with the highlighted caps is 100% post replacement. I looked through my photos and the only one I have pre-replacement is one of the big boy which was definitely bulging.
                              Sorry, lol.
                              ASRock B550 PG Velocita

                              Ryzen 9 "Vermeer" 5900X

                              32 GB G.Skill RipJaws V F4-3200C16D-32GVR

                              Sapphire Nitro+ Radeon RX 6750 XT

                              eVGA Supernova G3 750W

                              Western Digital Black SN850 1TB NVMe SSD

                              Alienware AW3423DWF OLED




                              "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

                              "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

                              "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                              "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                              Comment


                                #16
                                Re: Sceptre X322BV-HD - No Power

                                I rigged a new fuse and it blew instantly when I connected power, so I'll have to try and do the bridge rectifier/MOSFET testing you mention.

                                Thanks for the help so far.

                                Comment

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