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VX 724 black screen green light flashing

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    #61
    Re: VX 724 black screen green light flashing

    I see a couple voltage regulators (3-pin device) on the left side of the logic board below the Toroid choke. Please the number and the voltage reading on 3 pins. Also try heat up the logic board with hair dryer to see if it changes the picture quality after 2~3 minutes of heat.
    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


      #62
      Re: VX 724 black screen green light flashing

      Jumper should be on 6.5 for a 17 inch panel

      https://www.badcaps.net/forum/showthread.php?t=14776
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

      Comment


        #63
        Re: VX 724 black screen green light flashing

        Originally posted by budm View Post
        I see a couple voltage regulators (3-pin device) on the left side of the logic board below the Toroid choke. Please the number and the voltage reading on 3 pins. Also try heat up the logic board with hair dryer to see if it changes the picture quality after 2~3 minutes of heat.
        I can't read the number but It says something like "xxx 5FAL - 1117L".

        The readings are (with the black lead on ground)

        Vr1

        Pin 1: 13,2v AC --- 2v DC
        Pin 2: 13,2v AC --- 2v DC
        Pin 3: 13,2v AC --- 2v DC
        Pin 2-1: 0 Ohm
        Pin 2-3: 197 Ohm

        Vr2

        Pin 1: 13,2v AC --- 2v DC
        Pin 2: 13,2v AC --- 2v DC
        Pin 3: 13,2v AC --- 2v DC
        Pin 2-1: 0 Ohm
        Pin 2-3: 197 Ohm

        Vr3 (on the board with the VTI 03601)

        Pin 1: 13,2v AC --- 2v DC
        Pin 2: 13,2v AC --- 2v DC
        Pin 2-1: 0 Ohm
        Pin 2-3: 127 Ohm

        (From the power board, LEFT to RIGHT).

        I don't have a hair dryer. Is it the same if I use my hot air gun?

        Originally posted by selldoor View Post
        Jumper should be on 6.5 for a 17 inch panel

        https://www.badcaps.net/forum/showthread.php?t=14776
        Thanks!
        Last edited by Nocta; 04-14-2012, 02:14 PM.

        Comment


          #64
          Re: VX 724 black screen green light flashing

          Originally posted by Nocta View Post
          Pin 1: 13,2v AC --- 2v DC
          Pin 2: 13,2v AC --- 2v DC
          Pin 3: 13,2v AC --- 2v DC
          1117 voltage regulators output DC voltage (not AC). Put your black probe on a ground screw. Put your red probe on each pin. Put your multimeter on 20V DC if manual. Retest and report new readings.

          If your readings are actually 2V DC for each pin, then all your voltage regulators are shorted. That would make sense since pin 1-2 readings are 0 ohms. Alternatively, something else on the logic board is shorted making it look like all your voltage regulators are shorted.
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            #65
            Re: VX 724 black screen green light flashing

            @retiredcaps - he has a picture its just a bit fuzzy -would he get that if all 1117s are shorted or he had a short on the board
            Please upload pictures using attachment function when ask for help on the repair
            http://www.badcaps.net/forum/showthread.php?t=39740

            Comment


              #66
              Re: VX 724 black screen green light flashing

              Originally posted by selldoor View Post
              @retiredcaps - he has a picture its just a bit fuzzy -would he get that if all 1117s are shorted or he had a short on the board
              I believe it is possible. Just a couple of days ago we had this case of a shaky jittery image due to a voltage regulator running at 1.2V instead of 1.8V DC. So if the 1117s are supposed to output 1.8V and they are outputting 2.0V, it could cause fuzziness.

              https://www.badcaps.net/forum/showthread.php?t=19936
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              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

              We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

              Please do not post inline and offsite as they slow down the loading of pages.

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                #67
                Re: VX 724 black screen green light flashing

                Okay then, I'm gonna find these voltage regulators on the market because if I buy them on eBay, it'll take at least 15 bussiness days.
                But first of all, I'll have to look for the number of the resistors.


                I found the service manual for this monitor. It says that if the display color is "abnormal" then I should check U3 (which is a voltage regulator). I'm looking at the diagrams and it seems that VR are shorted, the output should be 3.3v insted of 2v ...

                Is it OK if I replace it with AS-1117? It's a 3-pin voltage regulator and the output is 3.3v and 800mA.
                Last edited by Nocta; 04-14-2012, 09:52 PM.

                Comment


                  #68
                  Re: VX 724 black screen green light flashing

                  Originally posted by Nocta View Post
                  Is it OK if I replace it with AS-1117? It's a 3-pin voltage regulator and the output is 3.3v and 800mA.
                  The original part number has no suffix to denote an output voltage so it sounds like an adjustable voltage regulator not a fixed one.
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                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                  We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                  Please do not post inline and offsite as they slow down the loading of pages.

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                    #69
                    Re: VX 724 black screen green light flashing

                    I looked at the service manual for the logic board power supply section, it looks like it uses the adjustable 1117 series, it also has 5v step-down switching regulator also so you may want to check those caps.. The stuff in the dash line are not used, I believe.
                    Attached Files
                    Last edited by budm; 04-14-2012, 10:32 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


                      #70
                      Re: VX 724 black screen green light flashing

                      Originally posted by retiredcaps View Post
                      The original part number has no suffix to denote an output voltage so it sounds like an adjustable voltage regulator not a fixed one.
                      Originally posted by budm View Post
                      I looked at the service manual for the logic board power supply section, it looks like it uses the adjustable 1117 series, it also has 5v step-down switching regulator also so you may want to check those caps.. The stuff in the dash line are not used, I believe.
                      I fully recapped the board, so caps are new and working. I'm gonna buy new voltage regulators on Monday, they're not expensive at all.

                      Thanks!
                      Last edited by Nocta; 04-14-2012, 11:08 PM.

                      Comment


                        #71
                        Re: VX 724 black screen green light flashing

                        Originally posted by Nocta View Post
                        I'm gonna buy new voltage regulators on Monday, they're not expensive at all.
                        Desolder the old ones and verify they are shorted out of circuit.

                        I have a Dell monitor and both voltage regulators on the logic board are shorted. So it is not the first time that all the voltage regulators on a board have been shorted.
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                          #72
                          Re: VX 724 black screen green light flashing

                          I'm trying but I can't desolder the VR. I guess I'll just have to wait and buy a rework station. I've been waiting for it for almost 20 days. There're some troubles importing products.

                          Comment


                            #73
                            Re: VX 724 black screen green light flashing

                            Originally posted by Nocta View Post
                            I'm trying but I can't desolder the VR.
                            From the same referenced thread in post #66

                            https://www.badcaps.net/forum/showpo...3&postcount=26
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                            If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                            We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                            Please do not post inline and offsite as they slow down the loading of pages.

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                              #74
                              Re: VX 724 black screen green light flashing

                              Great. I took the coil and some caps off because the space is reduced. After that, I desoldered the VR

                              Comment


                                #75
                                Re: VX 724 black screen green light flashing

                                I cut the legs and add more solder to the tab, the trick is to use wide tip soldering iron with at least 40watts.
                                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


                                  #76
                                  Re: VX 724 black screen green light flashing

                                  Originally posted by budm View Post
                                  I cut the legs and add more solder to the tab, the trick is to use wide tip soldering iron with at least 40watts.
                                  Is your definition of wide at least 3.2mm? I have one of these tips on order as my current one is 1.6mm.
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                                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                                  We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                                  Please do not post inline and offsite as they slow down the loading of pages.

                                  --- end sig file ---

                                  Comment


                                    #77
                                    Re: VX 724 black screen green light flashing

                                    I use Weller PTC7 (1/8", 3mm) for de-soldering works and PTA7 for soldering work on my old faithful Weller soldering station.
                                    http://compare.ebay.com/like/2510385..._lwgsi=y&cbt=y
                                    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


                                      #78
                                      Re: VX 724 black screen green light flashing

                                      I changed the VR and still no joy :/ I replaced them with AS1117.
                                      Last edited by Nocta; 04-17-2012, 12:26 PM.

                                      Comment


                                        #79
                                        Re: VX 724 black screen green light flashing

                                        What voltage reading are you getting now?
                                        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


                                          #80
                                          Re: VX 724 black screen green light flashing

                                          Now less than 2v but I think that I burned some caps using the soldering iron. I burned the plastic of a couple of them (even though I took them off for soldering the VR).
                                          A couple of minutes ago, I got more than 9v more or less.

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