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Samsung UN50H5203 Blinking Standby light

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    Samsung UN50H5203 Blinking Standby light

    Hi folks,
    I just got this Samsung TV, and all I get out of it is 6 blinks of the red standby light. TV seems responsive to remote and button.

    I started a bit backwards and went right to the LED strips. 90% dead, only 6 LEDs work. I replaced all strips with a new set. Tested with an external tester and they all light up. Put the TV back together and same thing - 6 blinks of the standby light.

    I'd like to rule out the Power Supply board - there is no 'STBY' pin to main board. Can anyone suggest a way to force the backlight on, or help me troubleshoot this TV?
    Thanks
    Attached Files

    #2
    Re: Samsung UN50H5203 Blinking Standby light

    Unplugging the cable between main board and power supply board should cause the backlight to come on. Samsungs don't have blink codes. The blinking is the main board booting up. If the backlights come on with the cable disconnected, the main board is suspect.

    Similar model here. https://www.badcaps.net/forum/showthread.php?t=70123
    Last edited by neilc6; 09-29-2018, 03:54 PM.

    Comment


      #3
      Re: Samsung UN50H5203 Blinking Standby light

      Thanks... backlight does not come on with power cable disconnected between main board and power board

      Comment


        #4
        Re: Samsung UN50H5203 Blinking Standby light

        Measurements of the LED connectors (referenced to Chassis / GND), while unit is turned on (STNDBY LED off)
        Pin 1 (D+): 362.7 V
        Pin 2 (D+): 362.7 V
        Pin 3 (S1-): 344.1 V
        Pin 4 (S2+): 344.1 V
        Pin 5 (NC) : 0.01 V
        Pin 6 (S2-): 353.4 V
        Pin 7 (S3+): 353.4 V
        Pin 8 (D-): 362.3 V
        Pin 9 (D-): 362.3 V

        Does this point to a bad power supply board?
        Last edited by jason123; 09-29-2018, 07:40 PM.

        Comment


          #5
          Re: Samsung UN50H5203 Blinking Standby light

          Last check is for the DRV_ON and PS_ON signals toggling from the main board. This will confirm a PS board fault since the backlights should come on with cable disconnected.

          Comment


            #6
            Re: Samsung UN50H5203 Blinking Standby light

            Sorry, wrong post
            Last edited by yohnsee; 09-30-2018, 12:19 AM.
            Cheers, Janos

            Comment


              #7
              Re: Samsung UN50H5203 Blinking Standby light

              I don't see a DRV_ON signal. Is this the UD pin from Main?

              Comment


                #8
                Re: Samsung UN50H5203 Blinking Standby light

                This post says UD/OD may be an error signal so the board may not have a separate BL_ON signal. I would try replacing the PS but buy from a seller that takes returns.

                https://www.badcaps.net/forum/showth...7&highlight=ud

                Comment


                  #9
                  Re: Samsung UN50H5203 Blinking Standby light

                  So it doesn't seem there is a way to force the Backlight on? The voltages on the Backlight connectors are rather high. What does that mean? these are brand new backlight strips, and I tested them individually prior to installing. Also, backlight doesn't come on with the cable between main and ps is disconnected

                  Comment


                    #10
                    Re: Samsung UN50H5203 Blinking Standby light

                    Unplugging the cable between the PS and main is the way to test the backlights on Samsung TVs. There is no or very low voltage differential to the strips so they aren't getting any voltage. The TV going through the turn on process indicates your main board is probably ok.

                    Comment


                      #11
                      Re: Samsung UN50H5203 Blinking Standby light

                      Thanks .. i will order a new power board. It doesn't seem that it could be anything else. Thanks
                      I am assuming a schematic for BN44-00772a is not available and repairs are not worth it
                      Last edited by jason123; 09-30-2018, 12:58 PM.

                      Comment


                        #12
                        Re: Samsung UN50H5203 Blinking Standby light

                        https://www.shopjimmy.com/samsung-bn...-led-board.htm
                        If you look at the Voltage chart as printed on the board, the LED Voltage with load is 235VDC, you are getting over 300V which means the LED power supply is not seeing the load. Your LED panel has 3 LED strings (S1, S2, and S3) connected in series to form one large string. I would invest in LED tester that can test each LED string.
                        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


                          #13
                          Re: Samsung UN50H5203 Blinking Standby light

                          Thanks budm. This TV actually has 4 LED strips. They're all replaced with a new set. I thought it was a quick Backlight replacement and I put the Panel back together before checking the connection. I have a current limited power supply that I used to test each strip separately but I don't know how these are connected to the PS board. Any idea what these D, S,... mean?

                          Comment


                            #14
                            Re: Samsung UN50H5203 Blinking Standby light

                            Are not same as string, you can have 2, 3 or 4 strips connected in series to form the string, see how the traces on the bottom side of the board are done, you have 6 wires on that LED connector.
                            The two D+ pins are tied together and then connected to the Node of the LED string, the S1- is the Cathode of the LED string #1 which is then connected to the S2+ which is the Anode of the second string, the S2 - is the Cathode of the S2 string which is connected to S3+ which is the Anode of the 3 rd LED string, the Cathode of the third string is connected to the two D- which are tied together. You have open circuit that is why the Voltage went up over 300V. You need to verify that do have connection between the male pins of the power supply board all the way to the LED string, strips.
                            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


                              #15
                              Re: Samsung UN50H5203 Blinking Standby light

                              Thanks budm. That helps greatly. Applying current-limited supply of 75V to the female connector that plugs to the PS shows the strings turning on. It seems 3 strings are present (sorry about the confusion with strings / strips). one string has 15 LEDs (pin 8 and 7), another string also 15 LEDs (pin 6 and 4) and the last string is 2 strips (30 LEDs, pin 2 and 3.) Verified that the panel wiring is at least as expected as follows:

                              Applying Power to Pin 8 (D-) and pin 7 (S3+) turned one string on.
                              Applying Power to Pin 6 (S2-) and pin 4 (S2+) turned another string on
                              Applying Power to pin 2 (D+) and pin 3 (S1-) turned the last 2 strips (3rd string) on (I had to up the voltage to 95V since they're 30 LED total)

                              It seems they're connected inside the panel correctly, right? It seems the connection is coming to the female plug (that's where the voltage was applied)

                              Could there be another issue with the power supply to yield this result?
                              Last edited by jason123; 09-30-2018, 02:55 PM.

                              Comment


                                #16
                                Re: Samsung UN50H5203 Blinking Standby light

                                Unplug the LED connector from the power supply board, leave black probe on the chassis, red probe on either one of the D+ pin of the board then turn on the TV while watching the meter to see how high the Voltage goes up to then wait 10 seconds to see how low it goes down to then turn off the TV.
                                Now put the red probe on either one of the D- and repeat the test, reports the results.
                                Last edited by budm; 09-30-2018, 03:07 PM.
                                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


                                  #17
                                  Re: Samsung UN50H5203 Blinking Standby light

                                  D+ went to 265 V then up to 362.6 V. It stayed there and persisted. Never dropped down

                                  D- went to 362.1 V. It also stayed there and persisted. Never dropped down.

                                  Comment


                                    #18
                                    Re: Samsung UN50H5203 Blinking Standby light

                                    That is a strange result on the Cathode return line of the LED string to have the same Voltage as the supply side that feed the Anode of the LED string.
                                    TV unplugged TV, no LED connector in place again then check the resistance between D+ and D- pins of the board.
                                    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


                                      #19
                                      Re: Samsung UN50H5203 Blinking Standby light

                                      7.48 kOhm

                                      Comment


                                        #20
                                        Re: Samsung UN50H5203 Blinking Standby light

                                        https://www.badcaps.net/forum/attach...1&d=1538256450
                                        I just look at the picture, it looks like that section of LED driver gets around the diode D9XXand the ferrite beads inductor (B8xxx), please verify that the diode is OK, check it in diode mode and Ohm mode.
                                        Also check that rectangular cap with '2j 104j' printed on top, that cap is connected between D+ and D-, you have to remove the cap and check the resistance (not ESR) to see if it has bad leakage resistance or not.
                                        This is tough troubleshooting without the schematic, I will have to find time to trace out the circuit.
                                        Last edited by budm; 09-30-2018, 03:33 PM.
                                        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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