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Dynex DX-LCD32-09 Sound but no Picture

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    #21
    Re: Dynex DX-LCD32-09 Sound but no Picture

    Originally posted by tom66 View Post
    *Usually* with audio, the power supply is okay. For now, leave it alone, as you have no backlight, right? That's the first problem.

    This is confusing. What cables go from the inverter to other boards? Post a CLEAR picture of the connector on the inverter side, clear enough to see the labels next to the pins.
    As you can see, no cables are going to or from the inverter other than the power cable and the pink/blue wires going to the backlights. The multicolored cable on the mainboard (Pictured) is the one going to the T-Con Board. Confusing? Yeah I was scratching my head after looking at the setup.
    Attached Files

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      #22
      Re: Dynex DX-LCD32-09 Sound but no Picture

      Can you post an image of the PSU board, where the connectors go to the inverter, main board, etc. Clear and focused images of the text next to each connector.
      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


        #23
        Re: Dynex DX-LCD32-09 Sound but no Picture

        Originally posted by tom66 View Post
        Can you post an image of the PSU board, where the connectors go to the inverter, main board, etc. Clear and focused images of the text next to each connector.
        This is the best I could do without making them blurry.
        Attached Files

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          #24
          Re: Dynex DX-LCD32-09 Sound but no Picture

          According to ShopJimmy the only part in this TV that is used in other brands is the T-Con board which is also used in the Insignia NS-LCD32, iv'e seen the Insignia in other posts.

          Comment


            #25
            Re: Dynex DX-LCD32-09 Sound but no Picture

            Is the connector with PON, PWM and 24V/GND (5 positions each) the one going to the inverter?
            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.

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              #26
              Re: Dynex DX-LCD32-09 Sound but no Picture

              Originally posted by gorr35 View Post
              According to ShopJimmy the only part in this TV that is used in other brands is the T-Con board which is also used in the Insignia NS-LCD32, iv'e seen the Insignia in other posts.
              I'd be surprised if that's true. Remember that is a list of products that they know about. I've seen boards used in 50 different brands at once! (All in-store brands, apart from two: Sanyo and Hitachi.)
              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


                #27
                Re: Dynex DX-LCD32-09 Sound but no Picture

                Originally posted by tom66 View Post
                Is the connector with PON, PWM and 24V/GND (5 positions each) the one going to the inverter?
                Yes sir that's the one.

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                  #28
                  Re: Dynex DX-LCD32-09 Sound but no Picture

                  Originally posted by gorr35 View Post
                  Yes sir that's the one.
                  Plug the connector in. Measure the voltage at PON and PWM, relative to the case. You may have to pry your probe in where the wire sits, to get good contact. (Practice on the 24V pins first, so you know how to get a good contact.)
                  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


                    #29
                    Re: Dynex DX-LCD32-09 Sound but no Picture

                    Originally posted by tom66 View Post
                    Plug the connector in. Measure the voltage at PON and PWM, relative to the case. You may have to pry your probe in where the wire sits, to get good contact. (Practice on the 24V pins first, so you know how to get a good contact.)
                    relative to the case?

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                      #30
                      Re: Dynex DX-LCD32-09 Sound but no Picture

                      Originally posted by tom66 View Post
                      plug the connector in. Measure the voltage at pon and pwm, relative to the case. You may have to pry your probe in where the wire sits, to get good contact. (practice on the 24v pins first, so you know how to get a good contact.)
                      pon = 4.7
                      pwn = 3.2

                      Comment


                        #31
                        Re: Dynex DX-LCD32-09 Sound but no Picture

                        Originally posted by gorr35 View Post
                        That's why I was wondering if it's the mainboard considering i'm not getting a reading from some of the pins going from the psu to the mainboard as follows:
                        32v = 31.6 - 32.2 (Keeps jumping up & down)
                        9v = 0 (Nothing)
                        5v = 0 (Nothing)
                        16v = 0 (Nothing)
                        5v next to PON = 5.1v

                        Edit: Think I got that backwards....it's the connector on the power supply going to the mainboard that's not getting the good reading, so would it be a psu problem not feeding power to the mainboard? The problem i'm having with that is that i'm still getting audio from the mainboard.
                        Checked power connector going to the mainboard again while plugged into the connector:

                        32v = got 32.5
                        9v = got 9.0
                        5v = got 5.1
                        16v = got 15.7
                        5v = got 5.1
                        PON = got 2.5

                        Comment


                          #32
                          Re: Dynex DX-LCD32-09 Sound but no Picture

                          Originally posted by gorr35 View Post
                          pon = 4.7
                          pwn = 3.2
                          They look okay.

                          The first pin tells the inverter to come on. Probably anything higher than 2V is good.

                          The second pin controls the brightness of the display and it looks okay too. The range might be 0-5V.

                          I'm only speculating, it is possible a high voltage turns the inverter off. However the presence of a PWM signal is encouraging. So I *think* the mainboard is okay.

                          It seems you have either a faulty inverter, or faulty CCFLs. 80% of the time, the inverter is at fault, although occasionally the CCFLs are at fault. Are there any part #'s on the inverter board which might help in tracking down spares?

                          Do you notice any burn marks or hot spots on the board? Hot spots are usually easy to seen: the normally white silkscreen turns brown or grey, and the blue colour of the PCB can discolour, usually getting darker.

                          Originally posted by gorr35 View Post
                          Checked power connector going to the mainboard again while plugged into the connector:

                          32v = got 32.5
                          9v = got 9.0
                          5v = got 5.1
                          16v = got 15.7
                          5v = got 5.1
                          PON = got 2.5
                          Yes, plugging it in does help :p.
                          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.

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                            #33
                            Re: Dynex DX-LCD32-09 Sound but no Picture

                            tomm66 Thank you very much for the help and time you put into it! Yeah I have the part#
                            VIT68001.95.....I was hoping that if it was the inverter that I would be able to pinpoint the problem rather than spen $70.00 on a replacement. I'll shop around though.

                            Comment


                              #34
                              Re: Dynex DX-LCD32-09 Sound but no Picture

                              Originally posted by gorr35 View Post
                              tomm66 Thank you very much for the help and time you put into it! Yeah I have the part#
                              VIT68001.95.....I was hoping that if it was the inverter that I would be able to pinpoint the problem rather than spen $70.00 on a replacement. I'll shop around though.
                              Yeah don't spend $70 on an inverter, that's a rip off. (I get TVs with broken screens for next to nothing, filled with perfectly good boards, so selling an inverter for $70 would be easy money, these guys are just ripping people off.)

                              Please check the inverter for any burn marks before you buy. It's possible with a soldering iron to replace components relatively easily or at least determine if a new inverter is needed - otherwise the tubes need to be replaced (which isn't easy, it requires complete disassembly of the LCD panel module.)

                              More than happy to help .
                              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


                                #35
                                Re: Dynex DX-LCD32-09 Sound but no Picture

                                Originally posted by gorr35 View Post
                                relative to the case?
                                When I say that, I mean negative (black) lead is attached to the metal case of the TV. Red lead goes on each pin.
                                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


                                  #36
                                  Re: Dynex DX-LCD32-09 Sound but no Picture

                                  Originally posted by tom66 View Post
                                  When I say that, I mean negative (black) lead is attached to the metal case of the TV. Red lead goes on each pin.
                                  I'm OK with testing most parts, but I have to admit i'm not real familiar with testing Transformers on the inverter board....can someone tell me the correct way to test these things? As you can see in the picture, pins 1-4 are on the bottom and 5-6 on top. Do I set the ohm setting to 200? what multimeter probes go where? What numbers am I looking for? Is it better to remove them from the board to test them?
                                  Attached Files

                                  Comment


                                    #37
                                    Re: Dynex DX-LCD32-09 Sound but no Picture

                                    Originally posted by gorr35 View Post
                                    I'm OK with testing most parts, but I have to admit i'm not real familiar with testing Transformers on the inverter board....can someone tell me the correct way to test these things? As you can see in the picture, pins 1-4 are on the bottom and 5-6 on top. Do I set the ohm setting to 200? what multimeter probes go where? What numbers am I looking for? Is it better to remove them from the board to test them?
                                    No need to remove them from the board. Set the DMM to the 2000 ohm range and measure the resistance between pins 5 and 6. Adjust the range if necessary to get maximum resolution. I'd expect all of them to read the same. You're looking for one that is significantly different.

                                    PlainBill
                                    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                                    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                                    Comment


                                      #38
                                      Re: Dynex DX-LCD32-09 Sound but no Picture

                                      Originally posted by PlainBill View Post
                                      No need to remove them from the board. Set the DMM to the 2000 ohm range and measure the resistance between pins 5 and 6. Adjust the range if necessary to get maximum resolution. I'd expect all of them to read the same. You're looking for one that is significantly different.

                                      PlainBill
                                      I tested the transformers at both 200 and 2000 ohms and here's what I got (pictured)

                                      BTW: I did do the light trick in front of the screen and I do see a faint picture.
                                      Attached Files
                                      Last edited by gorr35; 09-12-2011, 03:16 PM.

                                      Comment


                                        #39
                                        Re: Dynex DX-LCD32-09 Sound but no Picture

                                        Originally posted by gorr35 View Post
                                        I tested the transformers at both 200 and 2000 ohms and here's what I got (pictured)

                                        BTW: I did do the light trick in front of the screen and I do see a faint picture.
                                        Those numbers make no sense whatsoever. Please attach a picture of your DMM to your next post.

                                        PlainBill
                                        For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                                        Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                                        Comment


                                          #40
                                          Re: Dynex DX-LCD32-09 Sound but no Picture

                                          Originally posted by PlainBill View Post
                                          Those numbers make no sense whatsoever. Please attach a picture of your DMM to your next post.

                                          PlainBill
                                          I was affraid you'd say that!
                                          Attached Files

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