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    Sharp LC40LE531E Red/Green flashing LED

    Hi,

    I have the above TV which will not turn on. I understand the flash code is pointing to a faulty inverter board:



    The main connector on the bottom connector has the following readings when the LED is blinking Red/Green (from left to right)

    1. 24v
    2. 24v
    3. 24v
    4. 24v
    5. N/C
    6. GND
    7. GND
    8. GND
    9. N/C
    10. N/C
    11. N/C
    12. 0.013v
    13. 3.3v
    14. N/C

    any ideas where to start?

    Thanks in advance.
    Attached Files

    #2
    Re: Sharp LC40LE531E Red/Green flashing LED

    Do you have 24V on each side of the fuse F1?
    Willing to help but I'm no expert.

    Comment


      #3
      Re: Sharp LC40LE531E Red/Green flashing LED

      your reading of the voltage on CN1 look not correct with pins NO
      you have pins 1-5 24V and from 6-10 GND , pin 11 are error out you wrote N/C

      second read the voltage on CN3 between VCC Pin1(red probe ) and led 1 & 2, same to the next VCC pin5 and led 3 & 4

      Comment


        #4
        Re: Sharp LC40LE531E Red/Green flashing LED

        Fuse F1 is good.

        I have rechecked what I listed for CN1 and i'm correct with the population of pins in the connector.

        With CN3, the connector to the LED strings I think I measured as you requested.
        As you look at the connector, with arrow on the right I used that as my + red reference That is pin1.

        1. VCC (+reference)
        2. LED1 10.50V
        3. LED2 10.56V
        4. NC
        5. VCC 0.0V
        6. LED3 10.58V
        7. LED4 10.55

        ..and the 2 electrolytics are fine ESR/capacitance wise
        Last edited by Nevillet; 01-12-2021, 04:15 PM. Reason: more info

        Comment


          #5
          Re: Sharp LC40LE531E Red/Green flashing LED

          Originally posted by Nevillet View Post
          Fuse F1 is good.

          I have rechecked what I listed for CN1 and i'm correct with the population of pins in the connector.

          With CN3, the connector to the LED strings I think I measured as you requested.
          As you look at the connector, with arrow on the right I used that as my + red reference That is pin1.

          1. VCC (+reference)
          2. LED1 10.50V
          3. LED2 10.56V
          4. NC
          5. VCC 0.0V
          6. LED3 10.58V
          7. LED4 10.55

          ..and the 2 electrolytics are fine ESR/capacitance wise
          CN3 pin 5 VCC , you need to use it as references to measure led 3 &4.
          i forget to mention this test of CN3 you need to put the probe on the test point then plug the set in wall socket to remark the high and low reading at each pins.

          i dont think the issue at inverter.. you have CN2 which i think its connected to the T-CON correct ?

          Comment


            #6
            Re: Sharp LC40LE531E Red/Green flashing LED

            12. 0.013v
            Pin 12 is ENA (BL-ON pin), <1V = Backlights OFF, > 2 ~ 2.5V = Backlights on
            TV is off, Put black probe on the chassis, red probe on PIN 12 (ENA = BL-ON), turn on the TV while watching the meter to see if it jumps up over 2VDC or not.
            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


              #7
              Re: Sharp LC40LE531E Red/Green flashing LED

              If I measure CN3 pin 5 VCC to pin 6 and pin 7 I read the same 10.5v
              This measurement is taken when the front LED is blinking red/green.

              If i disconnect the TV from the wall supply - then reconnect, the front LED goes solid red.
              If I measure CN3 in this state these are the readings:

              1. VCC
              2. LED1 (pin1 to pin2 = 1.75v)
              3. LED2 (pin1 to pin3 = 1.76v)
              4. NC
              5. VCC
              6. LED3 (pin5 to pin6 = 1.8v)
              7. LED4 (pin5 to pin7 = 1.68v)

              CN2 Connects to the T-Con board.

              Measuring CN1 pin12 with reference to ground:
              In standby 0.413v
              In 'on' 0.013v (using a Fluke 187 it does not appear to jump over 2v)

              Comment


                #8
                Re: Sharp LC40LE531E Red/Green flashing LED

                .
                Last edited by dick_barton; 01-13-2021, 07:46 AM.
                Willing to help but I'm no expert.

                Comment


                  #9
                  Re: Sharp LC40LE531E Red/Green flashing LED

                  Hi Dick,

                  I can't read any text in your 1:43 #8 posting.

                  Comment


                    #10
                    Re: Sharp LC40LE531E Red/Green flashing LED

                    Sorry. I initially replied with a comment but then noticed after posting that I had made a mistake. Once posted there is no way to delete the posting other than to blank it.
                    Willing to help but I'm no expert.

                    Comment


                      #11
                      Re: Sharp LC40LE531E Red/Green flashing LED

                      Understood. Many thanks.

                      Comment


                        #12
                        Re: Sharp LC40LE531E Red/Green flashing LED

                        Originally posted by Nevillet View Post
                        If I measure CN3 pin 5 VCC to pin 6 and pin 7 I read the same 10.5v
                        This measurement is taken when the front LED is blinking red/green.

                        If i disconnect the TV from the wall supply - then reconnect, the front LED goes solid red.
                        If I measure CN3 in this state these are the readings:

                        1. VCC
                        2. LED1 (pin1 to pin2 = 1.75v)
                        3. LED2 (pin1 to pin3 = 1.76v)
                        4. NC
                        5. VCC
                        6. LED3 (pin5 to pin6 = 1.8v)
                        7. LED4 (pin5 to pin7 = 1.68v)

                        CN2 Connects to the T-Con board.

                        Measuring CN1 pin12 with reference to ground:
                        In standby 0.413v
                        In 'on' 0.013v (using a Fluke 187 it does not appear to jump over 2v)
                        then do both test you mentioned again but you need to turn on the set with RC at time the front LED goes solid red

                        Comment


                          #13
                          Re: Sharp LC40LE531E Red/Green flashing LED

                          Hi,

                          The TV is face down on the bench and to disconnect from the AC outlet I have been pulling out the Live+Neutral connection from the power board.

                          I have not been using the remote control, rather the push buttons on the lower edge of the TV bezel to take it out of standby.

                          Is this not achieving the same results?

                          Comment


                            #14
                            Re: Sharp LC40LE531E Red/Green flashing LED

                            yes of course its same.. so mean all the voltage you posted at your POST#7 after you press power on the side panel of the tv...?

                            Comment


                              #15
                              Re: Sharp LC40LE531E Red/Green flashing LED

                              I remeasured everything. It looks like there is a problem with the Pin 6 measurement. The connector to the LED strings was connected during these readings.

                              Standby
                              Pin-1 VCC
                              Pin-2 V between P1 & P2 0.884v
                              Pin-3 V between P1 & P3 0.836v
                              Pin-4 No Connection
                              Pin-5 V between P7 & P5 0.543v
                              Pin-6 V between P7 & P6 0.010v
                              Pin-7 VCC


                              On
                              Pin-1 VCC
                              Pin-2 V between P1 & P2 10.55v
                              Pin-3 V between P1 & P3 10.24v
                              Pin-4 No Connection
                              Pin-5 V between P7 & P5 10.02v
                              Pin-6 V between P7 & P6 0.020v
                              Pin-7 VCC

                              Comment


                                #16
                                Re: Sharp LC40LE531E Red/Green flashing LED

                                Originally posted by Nevillet View Post
                                I remeasured everything. It looks like there is a problem with the Pin 6 measurement. The connector to the LED strings was connected during these readings.

                                Standby
                                Pin-1 VCC
                                Pin-2 V between P1 & P2 0.884v
                                Pin-3 V between P1 & P3 0.836v
                                Pin-4 No Connection
                                Pin-5 V between P7 & P5 0.543v
                                Pin-6 V between P7 & P6 0.010v
                                Pin-7 VCC


                                On
                                Pin-1 VCC
                                Pin-2 V between P1 & P2 10.55v
                                Pin-3 V between P1 & P3 10.24v
                                Pin-4 No Connection
                                Pin-5 V between P7 & P5 10.02v
                                Pin-6 V between P7 & P6 0.020v
                                Pin-7 VCC
                                are there typo ??
                                the one i remark it with red color ... you mean between pin7 LED 4 and Pin 5 VCC correct?

                                Comment


                                  #17
                                  Re: Sharp LC40LE531E Red/Green flashing LED

                                  as end.. CN3, seem the first group blue pin1 to white & black okay

                                  the second group blue pin 5 to white okay.. and to black pin 7 had open LED

                                  Comment


                                    #18
                                    Re: Sharp LC40LE531E Red/Green flashing LED

                                    No there is no typo. The voltage on P6-P7 is low in both states.

                                    Comment


                                      #19
                                      Re: Sharp LC40LE531E Red/Green flashing LED

                                      Sorry, Sorry.
                                      Crazy mistake on my part.
                                      Pin7 is not VCC for LED 3 & 4.
                                      Pin5 is VCC for pins 6 & 7

                                      I will recheck all tomorrow when I'm not so tired.

                                      Sincere thanks for your help

                                      Comment


                                        #20
                                        Re: Sharp LC40LE531E Red/Green flashing LED

                                        https://www.badcaps.net/forum/attach...0&d=1610474573

                                        What DC Voltage do you get on U3 Middle pin (big tab) with ref. to the negative leg one of 220uf 35V cap (the two caps are connected in parallel so you can use any one of the two caps)?
                                        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

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