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Sceptre x322bv-hd powers up w/sound-but no picture

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    Sceptre x322bv-hd powers up w/sound-but no picture

    Hi everyone- new member to Badcaps and posting, but a long-time viewer/observer/admirer of this site. Trying to trouble shoot the picture problem with this Sceptre 32'' LCD TV. When plugged in-- the "red" standby light illuminates. Using the remote to turn on.... the unit powers up and "blue" light illuminates, sound comes on and can hear the station but no picture appears. By no picture, i mean Black, not blue, no logo, nada. I have included a pic to show the layout of the circuit boards inside and what i'm thinking they are. Firstly, I have limited knowledge/experience with advanced electronics diagnosis and some of the lingo, but do have a basic grasp and skills to do most along with determination a soldering iron my older analog multimeter . I went ahead and replaced 8 of the CapXon caps right off the bat on what i'm understanding is the power supply/inverter board based on read threads here. I did notice there were 3 more CapXon caps on the other board....(the main/logic board?) which i will also replace just to eliminate them as suspects.
    A close visual inspection shows no obvious problems. No hums or sizzles. This is a new and more technical troubleshooting area for me and am not really sure where to start the diagnosis process other than replacing the caps. Any help and/or guidance is much appreciated.
    Attached Files

    #2
    Re: Sceptre x322bv-hd powers up w/sound-but no picture

    Check ec14 and ec10 on the power board. These are the caps laying down. Also check all diodes on the secondary side.
    The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

    Comment


      #3
      Re: Sceptre x322bv-hd powers up w/sound-but no picture

      Thanks dgtech for your reply. I did a visual check on ec10 & ec14...they appear to be ok. No bulging or swelling noticed.Not sure if they can be checked with my analog multimeter in the circuit?
      Not sure what you mean by secondary side? Not to familiar w/ the language.
      Are you referring to the back side of the power board? BTW is this a combo power /inverter board?? Are the diodes you're talking about the ones I highlighted?
      D8, D12, D13. Also, forgot to mention in my 1st post, Tested the dcv output of the connectors. got 5v on the standby pins- nothing on the rest.(see pics).
      Thanks
      Attached Files

      Comment


        #4
        Re: Sceptre x322bv-hd powers up w/sound-but no picture

        Secondary side was the output side. Can you see a picture with a flashlight?
        We're the voltages taken when the sound was heard.
        Last edited by Dgtech; 06-03-2014, 06:42 PM.
        The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

        Comment


          #5
          Re: Sceptre x322bv-hd powers up w/sound-but no picture

          let me reinstall power board & check it out.

          Comment


            #6
            Re: Sceptre x322bv-hd powers up w/sound-but no picture

            Check and see if the PFC voltage booster circuit is working or not since the inverter circuit (the big transformer with yellow tape, the two 3-pin power MOSFETs and the two red/brown caps) requires that voltage to work, you need to check the voltage RIGHT AT THE TWO legs of that main filter cap (the big black cap laying on its side).
            Are there any labels next to those white connectors, we need to verify if we do have BL_ON (INV_ON) or not.
            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


              #7
              Re: Sceptre x322bv-hd powers up w/sound-but no picture

              ok...dgtech...that would be a no with seeing a pic w/ the flashlight.
              also... the voltages were read when i had it on the bench & powered up only with NO tv cable or other input devices hooked up. So no to that too.
              A hello to Budm, thanks for jumping in. FYI, i did read through your Basic LCD monitors troubleshooting guide & LCD Flat panel TV troubleshooting guide. Nicely written i might add. Let me investigate your inquiry and get back with you both on that.
              Thank you.

              Comment


                #8
                Re: Sceptre x322bv-hd powers up w/sound-but no picture

                budm, The white connectors have no labeling on the board for them, however, the lower one heads down to the lower left side and the upper one heads to the lower right side of the tv panel.
                I checked the voltage @ the main filter cap(with the power on) but am unclear (through my inexperience) on what scale to read on the darn multimeter to get the correct reading ....so i took a pic of it.
                Attached Files

                Comment


                  #9
                  Re: Sceptre x322bv-hd powers up w/sound-but no picture

                  looks like its reading approx. 375 volts

                  Comment


                    #10
                    Re: Sceptre x322bv-hd powers up w/sound-but no picture

                    i rechecked the voltage at the main cap and get 160 in standby & 380 with power.
                    From what i've read the seems about right. What would be a logical next place to check?

                    Comment


                      #11
                      Re: Sceptre x322bv-hd powers up w/sound-but no picture

                      Voltage readings from PS output connectors:
                      Attached Files

                      Comment


                        #12
                        Re: Sceptre x322bv-hd powers up w/sound-but no picture

                        *bump*
                        Can anybody help me out?

                        Comment


                          #13
                          Re: Sceptre x322bv-hd powers up w/sound-but no picture

                          You have the right the right signals feeding the board, at this point the problem is in the backlight inverter section. Will need to look further in that section.
                          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


                            #14
                            Re: Sceptre x322bv-hd powers up w/sound-but no picture

                            Originally posted by cbr6861 View Post
                            Voltage readings from PS output connectors:
                            I don't think that there will be any voltages here without the proper load on the circuit. It is that circuit That has the problem.
                            This could be a solder joint issue. I would reflow the joints on the transformer. I have seen those little blue caps fail before too. How about a pic of the back of the power board.
                            Last edited by Dgtech; 06-05-2014, 09:33 AM.
                            The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

                            Comment


                              #15
                              Re: Sceptre x322bv-hd powers up w/sound-but no picture

                              Originally posted by budm View Post
                              You have the right the right signals feeding the board, at this point the problem is in the backlight inverter section. Will need to look further in that section.
                              so the voltages look as they should on those 2 white connectors at the top?
                              the ones you asked about before that aren't labeled.

                              Comment


                                #16
                                Re: Sceptre x322bv-hd powers up w/sound-but no picture

                                Originally posted by Dgtech View Post
                                I don't think that there will be any voltages here without the proper load on the circuit. It is that circuit That has the problem.
                                This could be a solder joint issue. I would reflow the joints on the transformer. I have seen those little blue caps fail before too. How about a pic of the back of the power board.
                                will post it

                                Comment


                                  #17
                                  Re: Sceptre x322bv-hd powers up w/sound-but no picture

                                  Those two connectors will have about the 2000V output for the lamps, do not try to measure them unless you want to destroy your meter. As I indicate, you have the correct voltages feeding and outputting to and from the power supply, but you do not have the high voltage to drive the lamps, which is done by the inverter circuits.
                                  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


                                    #18
                                    Re: Sceptre x322bv-hd powers up w/sound-but no picture

                                    Those are high voltage connectors for the back lights. Sometimes the circuit senses whether or not the proper load is present or not. The board sometimes will not provide these voltages until the needed conditions are met.
                                    The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

                                    Comment


                                      #19
                                      Re: Sceptre x322bv-hd powers up w/sound-but no picture

                                      The inverter circuit will fire up first (load or no load), if it does not detect the lamp that fire up and stay conducts (or open lamp) in the in the first 3 seconds, it will go into shut down, it will fire up first and shutdown later. Right now he needs to look and see if the lamps even fired up at all.
                                      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


                                        #20
                                        Re: Sceptre x322bv-hd powers up w/sound-but no picture

                                        You can find out if the high voltage is even generated at all for seconds by using Neon lamp or using this:
                                        https://www.badcaps.net/forum/showth...x+dx-40l261a12
                                        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

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