Power supply on lt37hvs

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  • ricosavy
    Badcaps Veteran
    • Jul 2012
    • 457
    • united states
    #1

    Power supply on lt37hvs

    I have a tv model lt37hvs .The problem I am having is everything turns on for about 10 seconds the shuts off.You hear a clicking noise when it shuts off.I looked for bad solder joints the only thing I find is a shorted Zener diode but I can not find a way to identify it so I can replace it.It seems to connect to one of the legs of 20n60c3.power supply model is aep001 9191170013 rev3.looks like a fast acting diode d22 maybe it being shorted is shutting down my power supply.any help is welcomed thanks
    Attached Files
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    • ricosavy
      Badcaps Veteran
      • Jul 2012
      • 457
      • united states
      #2
      Re: Power supply on lt37hvs

      Here pic of 20n60c3
      Attached Files

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA
          #3
          Re: Power supply on lt37hvs

          That is the Gate discharge diode (it is in series with R76) which there is another resistor connected in parallel with that D/R.
          That circuit is the PFC Voltage booster so if the circuit does not work then you will not have >360VDC on the main filter cap, so you need to check that voltage.
          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

            • ricosavy
              Badcaps Veteran
              • Jul 2012
              • 457
              • united states
              #4
              Re: Power supply on lt37hvs

              What happen if the diode is shorted

                Comment

                • ricosavy
                  Badcaps Veteran
                  • Jul 2012
                  • 457
                  • united states
                  #5
                  Re: Power supply on lt37hvs

                  Lifted one leg the doide is not shorted I will pull my esr and check my caps

                    Comment

                    • CapLeaker
                      Leaking Member
                      • Dec 2014
                      • 8028
                      • Canada
                      #6
                      Re: Power supply on lt37hvs

                      That happens, sometimes diodes shows a short in circuit, just to take it out and it may be good. That all depends on the circuit the diode is in.

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA
                          #7
                          Re: Power supply on lt37hvs

                          Gate drive will usually have diode in parallel wit 10 Ohms resistor.
                          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

                            • fluffmeister9
                              Member
                              • Feb 2015
                              • 24
                              • usa
                              #8
                              Re: Power supply on lt37hvs

                              I have a LT37HVS and have replaced the capacitors and while the power light comes on the minute I turn the tv on it shorts out or shuts down totally. I can unplug the tv and plug it back in and the power light comes back on but I get no picture or sound. Any hints?

                                Comment

                                • ricosavy
                                  Badcaps Veteran
                                  • Jul 2012
                                  • 457
                                  • united states
                                  #9
                                  Re: Power supply on lt37hvs

                                  This is what i found on mine the solder joints on the power supply where connectors connect had bad joints so i just resolder them also the heat sink near the power plug had bad solder joints i resoldered it and the tv stays on now.
                                  Attached Files

                                    Comment

                                    • CapLeaker
                                      Leaking Member
                                      • Dec 2014
                                      • 8028
                                      • Canada
                                      #10
                                      Re: Power supply on lt37hvs

                                      great work!

                                        Comment

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