Acoustic solutions LCD26761HDF no backlight

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  • sienoki
    sienoki
    • Jan 2012
    • 314

    #1

    Acoustic solutions LCD26761HDF no backlight

    This set will display an image under flashlight..its got 17PW26-1-V3 psu...17MB35-1 mainboard...VIT70063.50-REV3 inverter board.

    When arial in will only display no signal so not sure on sound..there is no bloated caps..several HEC..SAMXON..CHANG caps on psu.
    Ive tested fuse on psu that tested good..no power going to inverter from checking the 4 red wires as i get no readings
    Attached Files
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Acoustic solutions LCD26761HDF no backlight

    The 24vdc to the Inverter will not be there until the PS_ON (ABOUT 3.3~5VDC) is supplied by the main board is sent to the power supply to turn on the 24vdc and 12vdc power supply to turn on.
    I wrote up a basic guide here:
    http://www.fixya.com/support/r509388...shooting_guide

    I aalos post a lot of pictures here:
    Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
    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

    • sienoki
      sienoki
      • Jan 2012
      • 314

      #3
      Re: Acoustic solutions LCD26761HDF no backlight

      Originally posted by budm
      The 24vdc to the Inverter will not be there until the PS_ON (ABOUT 3.3~5VDC) is supplied by the main board is sent to the power supply to turn on the 24vdc and 12vdc power supply to turn on.
      I wrote up a basic guide here:
      http://www.fixya.com/support/r509388...shooting_guide

      I aalos post a lot of pictures here:
      Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
      What should i be checking next..thx

      Comment

      • sienoki
        sienoki
        • Jan 2012
        • 314

        #4
        Re: Acoustic solutions LCD26761HDF no backlight

        Originally posted by sienoki
        What should i be checking next..thx
        Readings from mb pin with multimeter on 20v setting & tv switched on
        1.0.00
        2.8.18
        3.2.88
        4.0.00
        5.0.45
        6.0.13
        7.5.09
        8.3.37
        9.0.51
        10.0.51
        11.0.51
        12.0.16
        13.0.05

        Comment

        • sienoki
          sienoki
          • Jan 2012
          • 314

          #5
          Re: Acoustic solutions LCD26761HDF no backlight

          Originally posted by sienoki
          Readings from mb pin with multimeter on 20v setting & tv switched on
          1.0.00
          2.8.18
          3.2.88
          4.0.00
          5.0.45
          6.0.13
          7.5.09
          8.3.37
          9.0.51
          10.0.51
          11.0.51
          12.0.16
          13.0.05
          can any 1 suggest my next step in trouble shooting this set plz..thx

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: Acoustic solutions LCD26761HDF no backlight

            Check the diode for the 24V output.

            Any audio?

            This supply might power the main board 5V and 3.3V directly from the standby supply and the inverter from the main supply only.

            Looks reasonably decent for a Vestel aside from the caps... rare sight.
            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

            Comment

            • sienoki
              sienoki
              • Jan 2012
              • 314

              #7
              Re: Acoustic solutions LCD26761HDF no backlight

              Originally posted by tom66
              Check the diode for the 24V output.

              Any audio?

              This supply might power the main board 5V and 3.3V directly from the standby supply and the inverter from the main supply only.

              Looks reasonably decent for a Vestel aside from the caps... rare sight.
              Which diode do i test tom..a good diode will have a reading 1 way & OL the other way right?
              Theres dosnt seem to be any audio with tv areil in just says no signal..will get back on to this set when finished decorating house..
              Should i desolder 1 leg of the diodes for a good reading..thx

              Comment

              • tom66
                EVs Rule
                • Apr 2011
                • 32560
                • UK

                #8
                Re: Acoustic solutions LCD26761HDF no backlight

                Originally posted by sienoki
                Which diode do i test tom..a good diode will have a reading 1 way & OL the other way right?
                Theres dosnt seem to be any audio with tv areil in just says no signal..will get back on to this set when finished decorating house..
                Should i desolder 1 leg of the diodes for a good reading..thx
                The three legged device on the heatsink near the 24V connector is the device I am referring to.

                Fingers work as good antennas sometimes... at least where I am because we are fairly close to Hannington TX.

                I'm asking about the audio because I recall some Vestel sets used 24V to power the audio too so if this is missing you will get no inverter and no audio.

                No need to remove the device unless results are inconclusive.
                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                Comment

                • sienoki
                  sienoki
                  • Jan 2012
                  • 314

                  #9
                  Re: Acoustic solutions LCD26761HDF no backlight

                  Originally posted by tom66
                  The three legged device on the heatsink near the 24V connector is the device I am referring to.

                  Fingers work as good antennas sometimes... at least where I am because we are fairly close to Hannington TX.

                  I'm asking about the audio because I recall some Vestel sets used 24V to power the audio too so if this is missing you will get no inverter and no audio.

                  No need to remove the device unless results are inconclusive.
                  The diode Q827 connected to heatsink closest to the inverter plug on psu is a STPS20S100CFP-7PAAF-VW is this the diode a power schottky rectifier?
                  if so the readings are R-red..B-black measured with fluke77 series II
                  B1-R2=1.069
                  R1-B2=.261
                  B2-R3=.261
                  R2-B3=1.069
                  Theres another 1 on another heatsink same part no schottky which measures
                  same B-R as above with readings of
                  .570
                  .250
                  .249
                  .555
                  do these readings appear correct?

                  Comment

                  • tom66
                    EVs Rule
                    • Apr 2011
                    • 32560
                    • UK

                    #10
                    Re: Acoustic solutions LCD26761HDF no backlight

                    Is it definitely a "Q"? Might be a MOSFET then not a schottky. More difficult to test. You will need to remove it first to test it.
                    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: Acoustic solutions LCD26761HDF no backlight

                      Are there any labeling on the white pin to the right of the power supply board? The one on the top left is for the 24vdc, dimm, and Backlight_ON connectionS which goes to the inverter board.
                      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

                      • sienoki
                        sienoki
                        • Jan 2012
                        • 314

                        #12
                        Re: Acoustic solutions LCD26761HDF no backlight

                        Originally posted by budm
                        Are there any labeling on the white pin to the right of the power supply board? The one on the top left is for the 24vdc, dimm, and Backlight_ON connectionS which goes to the inverter board.
                        All the mosfetts or schottky attached the the heatsinks are marked Q with no on psu...the white pin out PL816 has no labelling or markings any where on psu for output voltages
                        Attached Files
                        Last edited by sienoki; 02-24-2012, 03:18 PM.

                        Comment

                        • tom66
                          EVs Rule
                          • Apr 2011
                          • 32560
                          • UK

                          #13
                          Re: Acoustic solutions LCD26761HDF no backlight

                          The STPS20S100CFP is a power schottky, see here: https://cdn.badcaps-static.com/pdfs/...b186bda3b6.pdf

                          Post a picture of the underside of the board.

                          It is probably 24V.
                          Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                          For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                          Comment

                          • budm
                            Badcaps Legend
                            • Feb 2010
                            • 40746
                            • USA

                            #14
                            Re: Acoustic solutions LCD26761HDF no backlight

                            One of those pin on the White connector with double-row pin on the right side of the P.S. board will be for PS_ON signal input from the main board, but since the board is not labeled, it will be hard to trace out the connections.
                            The red wires on the balck connector on the left side of the board will be the 24vdc out put.
                            I agree with Tom66, the good clear pictures of the bottom side of the board may help us tracing out the connections.
                            Last edited by budm; 02-24-2012, 03:39 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

                            • sienoki
                              sienoki
                              • Jan 2012
                              • 314

                              #15
                              Re: Acoustic solutions LCD26761HDF no backlight

                              Originally posted by budm
                              One of those pin on the White connector with double-row pin on the right side of the P.S. board will be for PS_ON signal input from the main board, but since the board is not labeled, it will be hard to trace out the connections.
                              The red wires on the balck connector on the left side of the board will be the 24vdc out put.
                              I agree with Tom66, the good clear pictures of the bottom side of the board may help us tracing out the connections.
                              Desoldered that schottky readings are same sequence as 1st test
                              just stays on .OL
                              1 beep .279
                              1 beep .279
                              just stays on .OL
                              Attached Files

                              Comment

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA

                                #16
                                Re: Acoustic solutions LCD26761HDF no backlight

                                The first two pictures are really out off focus, I can hardly trace out the traces from the black connector to the surface mounted components.
                                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

                                • sienoki
                                  sienoki
                                  • Jan 2012
                                  • 314

                                  #17
                                  Re: Acoustic solutions LCD26761HDF no backlight

                                  Originally posted by budm
                                  The first two pictures are really out off focus, I can hardly trace out the traces from the black connector to the surface mounted components.
                                  I,ll have to borrow a decent camera as mine is s..t

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #18
                                    Re: Acoustic solutions LCD26761HDF no backlight

                                    Please make sure to put the camera in MACRO mode for good close up pictures.
                                    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

                                    • sienoki
                                      sienoki
                                      • Jan 2012
                                      • 314

                                      #19
                                      Re: Acoustic solutions LCD26761HDF no backlight

                                      Originally posted by budm
                                      Please make sure to put the camera in MACRO mode for good close up pictures.
                                      From the underside the 1st smd from the black connector is D861 a small black diode im presuming?this reads 806 one way & 198 the other..if this is a diode im guessing this is faulty right?..ive tested the other small smd black diodes & readings 1 way & stays on 1 the other..thx
                                      Tested that diode with my fluke as i tested it prior with my cheapy multimeter..readings from .OL it gives 1 beep & .208 the reverse .722
                                      The only markings on that D861 is AP..thx

                                      Ive found this while googling does it help till i can chase a decent camera thx..it was in another tv forum & said it was same layout..thx
                                      Attached Files
                                      Last edited by sienoki; 02-24-2012, 06:23 PM.

                                      Comment

                                      • sienoki
                                        sienoki
                                        • Jan 2012
                                        • 314

                                        #20
                                        Re: Acoustic solutions LCD26761HDF no backlight

                                        Originally posted by sienoki
                                        From the underside the 1st smd from the black connector is D861 a small black diode im presuming?this reads 806 one way & 198 the other..if this is a diode im guessing this is faulty right?..ive tested the other small smd black diodes & readings 1 way & stays on 1 the other..thx
                                        Tested that diode with my fluke as i tested it prior with my cheapy multimeter..readings from .OL it gives 1 beep & .208 the reverse .722
                                        The only markings on that D861 is AP..thx

                                        Ive found this while googling does it help till i can chase a decent camera thx..it was in another tv forum & said it was same layout..thx
                                        Sorry for measuring white pin out not properly 1-27
                                        1--0v 2--0v
                                        3--0v 4--07.9
                                        5--0v 6--0v
                                        7--0v 8--0v
                                        9--0v 10--0v
                                        11--11.8v 12--11.8v
                                        13--0v 14--05.0v
                                        15--03.2v 16--03.2v
                                        17--05.0v 18--03.3v
                                        19--05.0v 20--03.2v
                                        21--0v 22--03.2v
                                        23--0v 24--0v
                                        25--24.3v 26--24.2v
                                        27--24.3v

                                        Comment

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