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Dynex DX-L40-10A Won't turn on.

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    Dynex DX-L40-10A Won't turn on.

    Hello all. I am in need of your help. I picked up a free tv from work because it was being replaced, it won't turn on, and I can't find the cause of the problem.

    I hear a click when I plug it in but the red stand by light comes on and neither the remote or the touch pad will turn the set on or change the light to blue. I don't hear any other sounds from the circuitry when trying to power it up but in the dozen or so times I've plugged/unplugged it it's made sounds from the speakers a couple of times.

    I took a few voltage readings and there does seem to be something wrong to me. On the PS board the connector going to the main board is supposed to have 12v on at least 2 of those pins. I'm reading 9.8 on both pins labeled 12v.

    I don't really see any obvious damage but on the underside of the PS board there's some oily residue in one small area, like the part on the other side got too hot and cooked that spot, but nothing looks fried per say. That spot is in the first pic under the yellow banded piece in the upper left corner.

    I'm not sure what to check next and could use some guidance.
    Attached Files

    #2
    Re: Dynex DX-L40-10A Won't turn on.

    Need better pics with pinout from the PS connector going to the main board. Basically you can unplug this connector and force the power supply on with a 1k Ohm resistor between PSon and STBY voltage (5v), BLon (back light) and 5V. That should turn on the power supply rails and the backlight should be on. Then measure voltages again.

    I think your case is a main board problem.

    Comment


      #3
      Re: Dynex DX-L40-10A Won't turn on.

      I'll get better pics when I get home from work.

      Comment


        #4
        Re: Dynex DX-L40-10A Won't turn on.

        I had the same problem same set. Try to heat up the lower left of the main board.
        Attached Files

        Comment


          #5
          Re: Dynex DX-L40-10A Won't turn on.

          Pictures of the whole backside of the TV?
          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


            #6
            Re: Dynex DX-L40-10A Won't turn on.

            Originally posted by CapLeaker View Post
            Need better pics with pinout from the PS connector going to the main board. Basically you can unplug this connector and force the power supply on with a 1k Ohm resistor between PSon and STBY voltage (5v), BLon (back light) and 5V. That should turn on the power supply rails and the backlight should be on. Then measure voltages again.

            I think your case is a main board problem.
            Do you mean 2 resistors?

            Comment


              #7
              Re: Dynex DX-L40-10A Won't turn on.

              Yes, two resistors.
              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


                #8
                Re: Dynex DX-L40-10A Won't turn on.

                Originally posted by CapLeaker View Post
                Need better pics with pinout from the PS connector going to the main board. Basically you can unplug this connector and force the power supply on with a 1k Ohm resistor between PSon and STBY voltage (5v), BLon (back light) and 5V. That should turn on the power supply rails and the backlight should be on. Then measure voltages again.

                I think your case is a main board problem.
                Does it matter which 5v I use?

                Comment


                  #9
                  Re: Dynex DX-L40-10A Won't turn on.

                  Nvm it's clear to me now after reading it enough times! Lol

                  Comment


                    #10
                    Re: Dynex DX-L40-10A Won't turn on.

                    Just tried doing the resistor trick and I do hear the click noise as if the boards were hooked together but there's no backlight and it doesn't come on still.

                    One thing to ask tho did I need to leave the cable plugged or unplugged. I tried it unplugged.

                    I was also using 1/2W resistors

                    Comment


                      #11
                      Re: Dynex DX-L40-10A Won't turn on.

                      Unplugged from main.

                      You are tricking the PSU into thinking the mainboard is causing load on the connections thus initiating them.

                      Did you test voltages again? If so readings?

                      Also picture of the connector from PSU to main so we can see the voltage legends

                      Comment


                        #12
                        Re: Dynex DX-L40-10A Won't turn on.

                        Trying to upload pics from my phone and there's bad lighting.

                        I'm not having any luck with trying to upload from the phone so I'll have to do it at work tomorrow.

                        With the resistors in I am getting 5.3v at pin STB and still pulling 9.8v at both 5V S pins. All the rest read 0. That's on the PS board.

                        Comment


                          #13
                          Re: Dynex DX-L40-10A Won't turn on.

                          PS board pinout

                          GND
                          GND
                          STB
                          5V S
                          5V S
                          12V
                          12V
                          GND
                          BR1? BRL?
                          SW
                          GND
                          GND
                          5V M
                          5V M

                          Main board pinout

                          +5V
                          +5V
                          GND
                          GND
                          BL ON/OFF
                          DIMM
                          GND
                          +12V
                          +12V
                          +5VSB
                          +5VSB
                          ON/OFF
                          GND
                          GND

                          Comment


                            #14
                            Re: Dynex DX-L40-10A Won't turn on.

                            So you are saying that you unplugged the main board from the power supply and forced the power supply on and you are still getting 9.8v where you should get 12v?

                            Comment


                              #15
                              Re: Dynex DX-L40-10A Won't turn on.

                              Yes was going to ask the same, Did you mean the 12v pins rather than the 5V S?

                              Comment


                                #16
                                Re: Dynex DX-L40-10A Won't turn on.

                                Yes still getting 9.8 on the pins 3,4&5 down from the top. That would be the 5v pins on the PS board. If u want readings from the main board I'll have to do that tomorrow. Already closed it up for tonight.

                                Just so I'm on the same page the PS board is the tan one that the power wire connects to correct?
                                Last edited by Funda; 02-12-2015, 09:50 PM.

                                Comment


                                  #17
                                  Re: Dynex DX-L40-10A Won't turn on.

                                  Well I'm not getting 9.8 in pin 3. That's 5.3

                                  Comment


                                    #18
                                    Re: Dynex DX-L40-10A Won't turn on.

                                    Sorry for all the edits and extra posts. It's been a long day and I've had a few doses of "medicine" and a couple shots so I'm remembering things late and staggered. Lol

                                    Comment


                                      #19
                                      Re: Dynex DX-L40-10A Won't turn on.

                                      Pics would really help with labels of what voltage you get at each one as you previously stated :

                                      Originally posted by Funda View Post
                                      I'm reading 9.8 on both pins labeled 12v.

                                      Comment


                                        #20
                                        Re: Dynex DX-L40-10A Won't turn on.

                                        Now I am confused. First the 9.8v are on the 12v rail, now they are on the 5v rail? Make some new pictures. Also use your PS pinout list in post 13 and fill in all the voltages.
                                        Last edited by CapLeaker; 02-13-2015, 04:21 AM.

                                        Comment

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