Westinghouse A190E3-H01 no backlight / shutdown

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  • caphair
    Badcaps Legend
    • Nov 2011
    • 1249

    #1

    Westinghouse A190E3-H01 no backlight / shutdown

    This monitor powers on to green led you see a very quick backlight flicker but only if you're looking for it, there is an image (used flashlight to confirm) but soon after it goes into standby with orange led.

    Powering on and off will continue with same symptoms. You can also hear a high pitched noise.

    No bulging caps, I've tested the two P605 mosfet ic drivers in and out of circuit using a DMM set to diode range. They both tested fine, but could they still be bad? Only thing I can think of for this symptom and the associated high pitched noise. Any feedback would be appreciated.
    Attached Files
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Westinghouse A190E3-H01 no backlight / shutdown

    Do you smell Ozone? May be the tube's wire is arcing?
    Last edited by budm; 12-17-2014, 03:59 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

    • caphair
      Badcaps Legend
      • Nov 2011
      • 1249

      #3
      Re: Westinghouse A190E3-H01 no backlight / shutdown

      Originally posted by budm
      Do you smell Ozone? May be the tube is arcing?
      Hmm no I don't smell anything

      Comment

      • caphair
        Badcaps Legend
        • Nov 2011
        • 1249

        #4
        Re: Westinghouse A190E3-H01 no backlight / shutdown

        I removed the smd timer capacitor and made a solder bridge in it's place which connects to terminal 1 of inverter ic which is the timer pin. This prevented the monitor from quickly going into standby, and you can see an image with a flashlight but no backlight at all.

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Westinghouse A190E3-H01 no backlight / shutdown

          The transformer high voltage side winding tested OK on both inverter transformer?
          You may have to use two test lamps or build two of these to find out if it is the circuit problem or lamp problem.
          https://www.badcaps.net/forum/showth...er+testing+cfl
          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

          • caphair
            Badcaps Legend
            • Nov 2011
            • 1249

            #6
            Re: Westinghouse A190E3-H01 no backlight / shutdown

            Originally posted by budm
            The transformer high voltage side winding tested OK on both inverter transformer?
            You may have to use two test lamps or build two of these to find out if it is the circuit problem or lamp problem.
            https://www.badcaps.net/forum/showth...er+testing+cfl
            How exactly do I test the transformers? Does it matter which pins I measure resistance at? Am I looking for low or high ohms?

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: Westinghouse A190E3-H01 no backlight / shutdown

              Can get the numbers as printed on the transformer?
              Last edited by budm; 12-17-2014, 05:01 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

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #8
                Re: Westinghouse A190E3-H01 no backlight / shutdown

                I am surprised that your board looks so clean, I would still change a set of caps.
                Same board is also used in this one.
                http://s807.photobucket.com/user/bud...?sort=3&page=1
                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

                • caphair
                  Badcaps Legend
                  • Nov 2011
                  • 1249

                  #9
                  Re: Westinghouse A190E3-H01 no backlight / shutdown

                  Originally posted by budm
                  can get the numbers as printed on the trasnformer?
                  2874001501
                  mb710a

                  Comment

                  • caphair
                    Badcaps Legend
                    • Nov 2011
                    • 1249

                    #10
                    Re: Westinghouse A190E3-H01 no backlight / shutdown

                    I did not get any ohm reading while trying to measure secondary side of transformers.

                    There are four pins and I tried ever possible combination and meter didn't move from overload.

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: Westinghouse A190E3-H01 no backlight / shutdown

                      Originally posted by caphair
                      2874001501
                      mb710a
                      I see letter A on the side.
                      Nothing comes up with 2874001501.
                      Last edited by budm; 12-17-2014, 05:06 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

                      • retiredcaps
                        Badcaps Legend
                        • Apr 2010
                        • 9271

                        #12
                        Re: Westinghouse A190E3-H01 no backlight / shutdown

                        It should be in the 610 to 650 ohms range. These two start with same first 4 digits and should be good enough for a ball park estimate.

                        http://lcdparts.net/TransformerDetai...ProductID=3359

                        http://lcdparts.net/TransformerDetai...ProductID=3360
                        --- begin sig file ---

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                        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.

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                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #13
                          Re: Westinghouse A190E3-H01 no backlight / shutdown

                          Hi Retiredcaps, his transformer is not the same as LCdparts:
                          https://www.badcaps.net/forum/attach...3&d=1418851047
                          Last edited by budm; 12-17-2014, 05:21 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

                          • caphair
                            Badcaps Legend
                            • Nov 2011
                            • 1249

                            #14
                            Re: Westinghouse A190E3-H01 no backlight / shutdown

                            I don't see any other numbers than I've posted
                            Attached Files

                            Comment

                            • retiredcaps
                              Badcaps Legend
                              • Apr 2010
                              • 9271

                              #15
                              Re: Westinghouse A190E3-H01 no backlight / shutdown

                              Originally posted by budm
                              Hi Retiredcaps, his transformer is not the same as LCdparts:
                              https://www.badcaps.net/forum/attach...3&d=1418851047
                              Ahh, I couldn't tell on a little 9 inch netbook screen when I posted. Now that I'm on a bigger 19 inch monitor, I can see the pinouts are different.
                              --- begin sig file ---

                              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

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA

                                #16
                                Re: Westinghouse A190E3-H01 no backlight / shutdown

                                OK, try reading between point A and point B.
                                Attached Files
                                Last edited by budm; 12-17-2014, 09:58 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

                                • caphair
                                  Badcaps Legend
                                  • Nov 2011
                                  • 1249

                                  #17
                                  Re: Westinghouse A190E3-H01 no backlight / shutdown

                                  Originally posted by budm
                                  OK, try reading between point A and point B.
                                  I get .367 ohms for both on the 2k ohm scale

                                  How important are all those globs of glue? Had to remove it to measure
                                  Last edited by caphair; 12-17-2014, 10:21 PM.

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #18
                                    Re: Westinghouse A190E3-H01 no backlight / shutdown

                                    The glue are there to reduce the arc over between the pins of the high voltage.
                                    So they have the same resistance (367 Ohms) within 3%.
                                    But I re-read your post 1 again on this statement "
                                    This monitor powers on to green led you see a very quick backlight flicker but only if you're looking for it, there is an image (used flashlight to confirm) but soon after it goes into standby with orange led." if the inverter circuit is not working, the unit should not go into standby since there is no feedback signal that goes back to the logic board to tell the logic board to go into standby due to no backlights.
                                    So it still can be due to unstable power supply when the inverter is turned on and start drawing lots of current and cause the power supply to squeal.
                                    The power supply is always on the minute you plug into the outlet, when the power switch is activated, then the inverter will start drawing current, the T-CON also starts drawing current too.
                                    So try disconnecting the cable that goes to the T-CON board on the LCD panel and see if you can power up the monitor.
                                    At this point it may be wise to re-cap the board.
                                    BTW, when you check the MOSFET, what resistance do you get between the Source pin and the Drain pin?
                                    Last edited by budm; 12-17-2014, 10:50 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

                                    • caphair
                                      Badcaps Legend
                                      • Nov 2011
                                      • 1249

                                      #19
                                      Re: Westinghouse A190E3-H01 no backlight / shutdown

                                      Originally posted by budm
                                      The glue are there to reduce the arc over between the pins of the high voltage.
                                      So they have the same resistance (367 Ohms) within 3%.
                                      But I re-read your post 1 again on this statement "
                                      This monitor powers on to green led you see a very quick backlight flicker but only if you're looking for it, there is an image (used flashlight to confirm) but soon after it goes into standby with orange led." if the inverter circuit is not working, the unit should not go into standby since there is no feedback signal that goes back to the logic board to tell the logic board to go into standby due to no backlights.
                                      So it still can be due to unstable power supply when the inverter is turned on and start drawing lots of current and cause the power supply to squeal.
                                      The power supply is always on the minute you plug into the outlet, when the power switch is activated, then the inverter will start drawing current, the T-CON also starts drawing current too.
                                      So try disconnecting the cable that goes to the T-CON board on the LCD panel and see if you can power up the monitor.
                                      At this point it may be wise to re-cap the board.
                                      BTW, when you check the MOSFET, what resistance do you get between the Source pin and the Drain pin?
                                      I thought there should be no reading between primary and secondary side of a transformer? The 367 ohms doesn't mean they're shorted?

                                      I unplugged t-con and same issue with backlights.

                                      Mosfet Ics I measure:
                                      S1-D1(Two D1 pins) 570ohms
                                      S2-D2(Two D2 pins) 530 ohms

                                      S1-D1(Two D1 pins) 570 ohms
                                      S2-D2(Two D2 pins) 529 ohms

                                      Comment

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #20
                                        Re: Westinghouse A190E3-H01 no backlight / shutdown

                                        "Mosfet Ics I measure:
                                        S1-D1(Two D1 pins) 570ohms
                                        S2-D2(Two D2 pins) 530 ohms

                                        S1-D1(Two D1 pins) 570 ohms
                                        S2-D2(Two D2 pins) 529 ohms"

                                        Those are tested off the board and probe in both directions? There is body Diode on Source and Drain pin, so in one direction it should show as open circuit.
                                        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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