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Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

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    #21
    Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

    not sure but OFL seems low, could it be a voltage regulator on mainboard?

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      #22
      Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

      Originally posted by nomoresonys View Post
      not sure but OFL seems low, could it be a voltage regulator on mainboard?
      The OFL value is jumped from PD-15 (4.96V) with a ~800ohm resistor, not connected to MB.
      Last edited by beetle1303; 04-20-2022, 02:34 AM.

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        #23
        Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

        my bad, I missed that it wasn't connected to anything in post 13.

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          #24
          Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

          T7701 and T7702 have been known to be a problem on these models, maybe check them closely.

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            #25
            Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

            maybe try heating those looks like 6 electrolytic caps there by the connector on powerboard with a hairdryer, turn on and see if it does anything different, can you trace the ofl from connector to one of those caps, maybe one of them isn't up to par, what voltages are you getting on them with powerboard jumped?

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              #26
              Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

              Originally posted by nomoresonys View Post
              T7701 and T7702 have been known to be a problem on these models, maybe check them closely.
              I am not sure how accurately I checked. With DMM in Ohm mode, both input and output side measures 1-2 ohms only. Both T7701 & T7702 the same.

              When powered-up with jumped PD cable, the reads 0V on input pin-pair, and 0V on output pin-pairs.

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                #27
                Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                Originally posted by nomoresonys View Post
                maybe try heating those looks like 6 electrolytic caps there by the connector on powerboard with a hairdryer, turn on and see if it does anything different, can you trace the ofl from connector to one of those caps, maybe one of them isn't up to par, what voltages are you getting on them with powerboard jumped?
                I have earlier measures the capacitance of these caps, and all are on-par with the stated values. But I dont have the meter for ESR values.

                On powered-up with jumped pins, all these caps measured between 5-13+V, looks quite normal to me.

                What might not be normal is the T7901 - similar to T7701 & T7702, it measures mostly 0V on the input and output pin-pairs.

                What is the correct way to measure transformer in put and output voltages?

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                  #28
                  Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                  you should be getting voltage on some of those, on hot side you use the negative of one of the big filter caps as ground, so neg. probe on that and pos. probe on what you're checking.

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                    #29
                    Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                    if you still have no voltage when powered, maybe trace it to where it stops, which seems to be right after the big caps somewhere in that area.

                    Comment


                      #30
                      Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                      power boards are fine...
                      yours problem at MB, didn't send PS_ON... could be the MB tosted / dead or the SW or too the SPI flash.
                      the front LED when it blink its the first boot sequences of the SPI which it didn't complete... try freeze the SPI

                      Comment


                        #31
                        Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                        Originally posted by nomoresonys View Post
                        if you still have no voltage when powered, maybe trace it to where it stops, which seems to be right after the big caps somewhere in that area.
                        I am not getting any voltages on those 2 transformers. And you're right, after tracing the 400Vdc from the big caps to the component Q7700, and 0v output to the transformer.

                        I tested this transistor:
                        1) Red probe on middle pin:
                        Black probe on either pin - Open

                        2) Black probe on middle pin:
                        Red probe on left pin: 528
                        Red probe on right pin: 732

                        Does it sounds bad or OK?
                        Attached Files

                        Comment


                          #32
                          Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                          Originally posted by Diah View Post
                          power boards are fine...
                          yours problem at MB, didn't send PS_ON... could be the MB toasted / dead or the SW or too the SPI flash.
                          the front LED when it blink its the first boot sequences of the SPI which it didn't complete... try freeze the SPI
                          I am very convinced MB is completed toasted, since there is any shorts that causing fluctuating voltages like it was initially.

                          But I also curious about whether the BL is working since it has no power to he BL section of the PS.

                          From my precedent replying post - does it looks like BL is not working?

                          Question: What's a SPI ?
                          Last edited by beetle1303; 04-20-2022, 08:31 AM.

                          Comment


                            #33
                            Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                            wondering why the backlights didn't come on when powerboard is jumped, sure seems like they should.

                            Comment


                              #34
                              Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                              Originally posted by beetle1303 View Post
                              I am not getting any voltages on those 2 transformers. And you're right, after tracing the 400Vdc from the big caps to the component Q7700, and 0v output to the transformer.

                              I tested this transistor:
                              1) Red probe on middle pin:
                              Black probe on either pin - Open

                              2) Black probe on middle pin:
                              Red probe on left pin: 528
                              Red probe on right pin: 732

                              Does it sounds bad or OK?
                              .
                              Last edited by nomoresonys; 04-20-2022, 08:54 AM.

                              Comment


                                #35
                                Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                                Originally posted by nomoresonys View Post
                                wondering why the backlights didn't come on when powerboard is jumped, sure seems like they should.
                                There is no power supply to those 2 transformers, because Q7700 is either faulty or not triggered?

                                Comment


                                  #36
                                  Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                                  test q7700 again, put black probe on neg. of big cap and red probe on each leg of that fet.

                                  Comment


                                    #37
                                    Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                                    make sure your meter is set to at least 200 if it isn't an auto range meter.

                                    Comment


                                      #38
                                      Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                                      what happened? beer break?

                                      Comment


                                        #39
                                        Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                                        Originally posted by nomoresonys View Post
                                        what happened? beer break?
                                        Black probe on big cap negative, red on middle pin of Q7700 - 402VDC
                                        Black probe on big cap negative, red on either pin of Q7700 - 0VDC

                                        Repeated a few times..

                                        How does this Q7700 works?
                                        Last edited by beetle1303; 04-20-2022, 09:11 AM.

                                        Comment


                                          #40
                                          Re: Sharp LED TV flashing green 2x per second - LC-70LE735X, DPS-222BP, RUNTKA857WJQZ

                                          men... you are really funny... who care on BL if they come on or not when the MB dead.

                                          did you know which pin BL_ON ?? we tested panel 12V. and main 13V are good mean PCB 100% working
                                          what the diffrent if man his legs brocken and you insist to teach him dancing !!!!

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