Sharp LC-60SQ15U TV DPS-167CP - No power

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  • romasik
    Senior Member
    • May 2022
    • 56
    • Ukraine

    #101
    Re: Sharp LC-60SQ15U TV DPS-167CP - No power

    Originally posted by lotas
    Try like this.
    read pm please

    Comment

    • romasik
      Senior Member
      • May 2022
      • 56
      • Ukraine

      #102
      Re: Sharp LC-60SQ15U TV DPS-167CP - No power

      Originally posted by R_J
      PC7904 is used to turn on Q7902 to supply vcc_on so it can be left out of circuit for now.
      If you also remove pc7903 and D7908, pin 4 of ic7903 should be about 7volts, If it does not come up, try isolating just pin4 from the circuit trace, this will eliminate any other component on that line as well.
      What can you say about the removal of the supervisor, maybe maybe that's the reason?

      Comment

      • R_J
        Badcaps Legend
        • Jun 2012
        • 9533
        • Canada

        #103
        Re: Sharp LC-60SQ15U TV DPS-167CP - No power

        This is why I asked you to isolate pin 4 of the ic and check the voltage on just the ic pin4, This would eliminate EVERYTHING else connected to the ic.

        Comment

        • romasik
          Senior Member
          • May 2022
          • 56
          • Ukraine

          #104
          Re: Sharp LC-60SQ15U TV DPS-167CP - No power

          Originally posted by R_J
          This is why I asked you to isolate pin 4 of the ic and check the voltage on just the ic pin4, This would eliminate EVERYTHING else connected to the ic.
          I check 0 Volts

          Comment

          • R_J
            Badcaps Legend
            • Jun 2012
            • 9533
            • Canada

            #105
            Re: Sharp LC-60SQ15U TV DPS-167CP - No power

            Here is the block diagram of the ic I have no idea why you have 0 volts on pin4
            Is R7918 (0Ω) open?
            Are these NEW ic's or used?
            Attached Files

            Comment

            • romasik
              Senior Member
              • May 2022
              • 56
              • Ukraine

              #106
              Re: Sharp LC-60SQ15U TV DPS-167CP - No power

              Originally posted by R_J
              Here is the block diagram of the ic I have no idea why you have 0 volts on pin4
              Is R7918 (0Ω) open?
              Are these NEW ic's or used?
              Seller say these NEW, and say on 5 pin should be 15V for start IC and there will be no voltage on the 4th contact until it starts IC , R7918 not open (0Ω)

              Does it make sense to desolder the supervisor? Or can I just remove the resistors on pins 1 and 3? I read on other forums that it happens to be a common problem his of not give starting IC
              Last edited by romasik; 05-21-2022, 05:41 PM.

              Comment

              • R_J
                Badcaps Legend
                • Jun 2012
                • 9533
                • Canada

                #107
                Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                What do you have in place for D7950? Maybe disconnect whatever is in there and see if the vcc comes up.
                The ic's startup cell IS providing the initial 9volts, (at low current) so there can't be anything on that vcc line killing the voltage or you wouldn't have 9v. something is keeping the ic from oscillating.
                Last edited by R_J; 05-21-2022, 06:43 PM.

                Comment

                • romasik
                  Senior Member
                  • May 2022
                  • 56
                  • Ukraine

                  #108
                  Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                  Originally posted by R_J
                  What do you have in place for D7950? Maybe disconnect whatever is in there and see if the vcc comes up.
                  The ic's startup cell IS providing the initial 9volts, (at low current) so there can't be anything on that vcc line killing the voltage or you wouldn't have 9v. something is keeping the ic from oscillating.
                  On place D7950 i soldered SSL510 (SB5100 not yet in store)

                  Comment

                  • romasik
                    Senior Member
                    • May 2022
                    • 56
                    • Ukraine

                    #109
                    Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                    Originally posted by R_J
                    .
                    Hello Does it make sense to desolder the supervisor? Or can I just remove the resistors on pins 1 and 3 supervisor? And try desolder D7950?

                    Comment

                    • dskall
                      Badcaps Legend
                      • Oct 2016
                      • 2905
                      • usa

                      #110
                      Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                      Have you compared all pin voltages with datasheet?
                      I assume no responsibility for any stupid suggestions I might post.

                      Comment

                      • romasik
                        Senior Member
                        • May 2022
                        • 56
                        • Ukraine

                        #111
                        Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                        Originally posted by dskall
                        Have you compared all pin voltages with datasheet?
                        with datasheet suervisor?

                        Comment

                        • dskall
                          Badcaps Legend
                          • Oct 2016
                          • 2905
                          • usa

                          #112
                          Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                          With STR-A6000. Strike that
                          Last edited by dskall; 05-22-2022, 03:52 PM.
                          I assume no responsibility for any stupid suggestions I might post.

                          Comment

                          • dskall
                            Badcaps Legend
                            • Oct 2016
                            • 2905
                            • usa

                            #113
                            Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                            Originally posted by romasik
                            Hello, please help me i have same problem on my Sharp Aquos 60LC635E No 5V power, tv dead . Blown R7900 and short D7950 . I changed it, than blown R7900 again . D7950 ok. I change IC7903 and cap on 5 leg 50V 47u and R7900 never blown again but 5V not( I do not know what to do . On big two cap 315V, on 5 leg IC7903 9V this very low for start A6069H . Datasheet say min 13V.

                            Please Help me. board power supply dps-162KP B RUNTKA932WJQZ
                            Is that the right resistor wattage R7900? And you double checked that diode D7950 was installed right?
                            I assume no responsibility for any stupid suggestions I might post.

                            Comment

                            • romasik
                              Senior Member
                              • May 2022
                              • 56
                              • Ukraine

                              #114
                              Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                              Originally posted by dskall
                              Is that the right resistor wattage R7900? And you double checked that diode D7950 was installed right?
                              yes all check, resitor 2.2 ohm 0,5W, diode 100V 5A installed right.

                              Comment

                              • romasik
                                Senior Member
                                • May 2022
                                • 56
                                • Ukraine

                                #115
                                Re: Sharp LC-60SQ15U TV DPS-167CP - No power

                                I desolder supervisor and D7950 nothing change ((

                                Comment

                                • 68pishta
                                  Member
                                  • Jan 2012
                                  • 29

                                  #116
                                  I aquired this TV to attempt to fix. Found the R7900 open and D7950 diode shorted. Replaced both (5A diode only available) and this immediately popped IC7903 with a SNAP! Did the 5A diode cause this? There was nothing hooked to power board when it popped. I poked around some more and found D7904 looks to be shorted as well. I measured the pins on the T7901 and they all look good with no internal shorts across its individual windings. Where next? I saw where you can substitute a different style 5V regulator to the IC7903 with adding a resistor to one of the legs. I didnt check the SMD side for any damage, just a very quick repair of the 2 parts i initially found to be faulty.Click image for larger version

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                                  Comment

                                  • weaboth
                                    New Member
                                    • Feb 2023
                                    • 1
                                    • México

                                    #117
                                    Comparto mi experiencia, mi pantalla solo tenia los voltajes de stand by de 5v. Y mostraba un parpadeo corto y uno largo, al final encontre los leds da{ados y errores en la memoria de la main. Y tarde mucho por que crei que era error de los circuitos pfc; ya que les faltaba alimentacion al de pfc y el ncp.

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