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    No Stdby Light Samsung Ue46d5000

    Hey guys,

    I currently have a Samsung UE46D5000 which shows no reaction at all. There's no Standby light and no clicking noise. Already replaced the PSU, because the old one seemed faulty (no STDBY voltage, no other voltages), but it didn't change much.

    With the old PSU and disconnected mainboard the backlight did flash on and off. With the new (used) PSU and disconnected mainboard the backlight stays on.

    When I connect the mainboard the backlight turns off and the TV seems to be shut off.

    I tried to jumper the PSU (PS_On and A5V, which seemed to be 5V_SB), but this killed a small Transistor. The PSU still works.

    I found a damaged double Z-Diode (for the CI) on the mainboard and soldered it out.

    When everything was reassembled I checked the voltages again. The PSU seems to start and delivers all the Voltages correctly to the mainboard, but the IR/Button-board doesn't get any Voltage. It should have 5V(A5V) but instead this pin is shorted to ground. Í guess it shouldn't be shorted.

    Any ideas where to search the fault? I was not able to follow the traces of A5V from PSU to A5V IR board. They have no direct connection.
    Attached Files

    #2
    Re: No Stdby Light Samsung Ue46d5000

    *push*

    Comment


      #3
      Re: No Stdby Light Samsung Ue46d5000

      Originally posted by Fritz23 View Post
      Hey guys,

      I currently have a Samsung UE46D5000 which shows no reaction at all. There's no Standby light and no clicking noise. Already replaced the PSU, because the old one seemed faulty (no STDBY voltage, no other voltages), but it didn't change much.

      With the old PSU and disconnected mainboard the backlight did flash on and off. With the new (used) PSU and disconnected mainboard the backlight stays on.

      When I connect the mainboard the backlight turns off and the TV seems to be shut off.

      I tried to jumper the PSU (PS_On and A5V, which seemed to be 5V_SB), but this killed a small Transistor. The PSU still works.

      I found a damaged double Z-Diode (for the CI) on the mainboard and soldered it out.

      When everything was reassembled I checked the voltages again. The PSU seems to start and delivers all the Voltages correctly to the mainboard, but the IR/Button-board doesn't get any Voltage. It should have 5V(A5V) but instead this pin is shorted to ground. Í guess it shouldn't be shorted.

      Any ideas where to search the fault? I was not able to follow the traces of A5V from PSU to A5V IR board. They have no direct connection.
      Is the A5V pin on the IR/button-board still shorted out when the PCB is disconnected from the mainboard? If it is, the short is on the IR/button-board. If the mainboard has a short, then you can start checking the voltage regulators to find any that have a short. You can remove the regulator to see if it indeed is the regulator that is bad. If it's not bad, then the most likely thing would either be a shorted out IC or a shorted out ceramic capacitor.

      -Ben
      Muh-soggy-knee

      Comment


        #4
        Re: No Stdby Light Samsung Ue46d5000

        Hi there,

        I ended up buying a new mainboard for 25€, which solved the problem in combination with the new power supply.

        Anyways one year later I have the same TV with the same problem again. Still not even a standby light.

        I unmounted the power supply and am testing it on my table. Without anything connected it just makes a silent clicking noise every second. While trying to find a 5V standby line I just saw, that every voltage is jumping around between 0V to ~18V. Even the Power On/Off line jumps between 1.5V and 3V.

        I attached a diagram of the A5V line.

        There are no bulging caps and the main cap is charged to 385V. Checked both fuses.

        I'm quite surprised by this behavior and don't know what to do.
        Attached Files

        Comment


          #5
          Re: No Stdby Light Samsung Ue46d5000

          Check the resistance between GND and the A5V pin to see what you get.
          Pictures provided by shopjimmy.
          Attached Files
          Last edited by budm; 07-25-2016, 09:23 AM.
          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


            #6
            Re: No Stdby Light Samsung Ue46d5000

            GND-A5V -> Around 7 MOhm, but dropping while measuring.

            I did find the schematic online: BN44-00473A schematic

            Comment


              #7
              Re: No Stdby Light Samsung Ue46d5000

              Common issue with these is shorted Cpu and failed bga solder on the Cpu due to poor heatsinking.
              Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

              https://www.facebook.com/Telford-Tel...7894576335359/

              Comment


                #8
                Re: No Stdby Light Samsung Ue46d5000

                Originally posted by Fritz23 View Post
                GND-A5V -> Around 7 MOhm, but dropping while measuring.

                I did find the schematic online: BN44-00473A schematic
                OK, so the output side does not have shorts (no other boards connected to the power supply board at this point), the circuit ticking usually indicates shorts in the output side or bad startup/running caps or some thing is overloading the circuits and cause it to be in startup/shutdown cycle, next you should check the caps CS802, 805 ESR, you can also try heating them with hair dryer to see if the STBY A5V will become steady or just replace the caps.
                BTW, check the resistance between the two legs of cap cp804.
                Last edited by budm; 07-25-2016, 09:35 AM.
                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


                  #9
                  Re: No Stdby Light Samsung Ue46d5000

                  Originally posted by budm View Post
                  OK, so the output side does not have shorts (no other boards connected to the power supply board at this point), the circuit ticking usually indicates shorts in the output side or bad startup/running caps or some thing is overloading the circuits and cause it to be in startup/shutdown cycle, next you should check the caps CS802, 805 ESR, you can also try heating them with hair dryer to see if the STBY A5V will become steady or just replace the caps.
                  BTW, check the resistance between the two legs of cap cp804.
                  I currently don't have an ESR meter. Heating these caps didn't change anything.

                  I couldn't find a CP804. In the schematic it says CP804 is "N.C.". I measured the resistance between PFC-VCC and P-GND but it's too high to measure (over 20 Mohm)

                  Originally posted by ReeceyBurger123
                  Common issue with these is shorted Cpu and failed bga solder on the Cpu due to poor heatsinking.
                  Is there any way to check this?

                  Comment


                    #10
                    Re: No Stdby Light Samsung Ue46d5000

                    Originally posted by Fritz23 View Post
                    I currently don't have an ESR meter. Heating these caps didn't change anything.

                    I couldn't find a CP804. In the schematic it says CP804 is "N.C.". I measured the resistance between PFC-VCC and P-GND but it's too high to measure (over 20 Mohm)



                    Is there any way to check this?
                    I have you check the resistance where the CP804 is even though it is not installed is to find out if the PFC IC Vcc pin show low resistance or not, and it is 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


                      #11
                      Re: No Stdby Light Samsung Ue46d5000

                      Connect 100 Ohms resistor between the PS-ON pin and GND pin (this will turn off the PFC circuit), do the same to the BL-ON (BLU ON) pin and see if the A5V will be stable or not.
                      Last edited by budm; 07-25-2016, 10:14 AM.
                      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


                        #12
                        Re: No Stdby Light Samsung Ue46d5000

                        Originally posted by budm View Post
                        I have you check the resistance where the CP804 is even though it is not installed is to find out if the PFC IC Vcc pin show low resistance or not, and it is not.
                        Ok, so this IC is good, right?

                        Originally posted by budm View Post
                        Connect 100 Ohms resistor between the PS-ON pin and GND pin (this will turn off the PFC circuit), do the same to the BL-ON (BLU ON) pin and see if the A5V will be stable or not.
                        With 100 Ohms between PS-ON and GND A5V is stable at 5.26V. With 100 Ohms between BL-ON and GND A5V is still stable at 5.26V.
                        Last edited by Fritz23; 07-25-2016, 10:35 AM.

                        Comment


                          #13
                          Re: No Stdby Light Samsung Ue46d5000

                          Originally posted by Fritz23 View Post
                          Ok, so this IC is good, right?



                          With 100 Ohms between PS-ON and GND A5V is stable at 5.26V. With 100 Ohms between BL-ON and GND A5V is still stable at 5.26V.
                          OK, we are getting some where.
                          Now check the resistance between GND and the Collector of the switched/Linear regulator transistor QM801 (This transistor supplies the VCC to run the ICM801) to see if it shows low resistance.
                          Last edited by budm; 07-25-2016, 10:56 AM.
                          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


                            #14
                            Re: No Stdby Light Samsung Ue46d5000

                            Collector of QM801 to P-GND shows 3.46 kOhms in one way and 9.91 kOhms the other way.

                            Comment


                              #15
                              Re: No Stdby Light Samsung Ue46d5000

                              Is there any way you can disconnect the Collector so that Transistor will not be supplying the VCC to ICM801 and then you can remove the resistor between the PS-ON pin and the GND to see if the A5V will still be at 5V?
                              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


                                #16
                                Re: No Stdby Light Samsung Ue46d5000

                                I disconnected the collector of QM801 (E and B still connected) and removed the 100 ohms resistor between PS-ON and GND. Resistor between BL-ON and GND stays.

                                A5V still stable at 5.26V.

                                Comment


                                  #17
                                  Re: No Stdby Light Samsung Ue46d5000

                                  OK, What DCV do you have on the Collector?
                                  Do you now get about 400VDC between the two legs of the main filter cap? It should since we now should have VCC feeding the PFC IC.
                                  so it is something in the Backlights circuit, I suspect the ICM801 or the filter caps connected to the VCC pin of the ICM801.
                                  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


                                    #18
                                    Re: No Stdby Light Samsung Ue46d5000

                                    I get 14.6 DCV on the collector.
                                    Main cap is charged to 392 VDC.

                                    It wouldn't be the first time that such an IC failed. Is there anything more to check to determine if it's the ICM801 or the caps (you mean the ceramic caps CM802, 803, 804, 805, 806, 809 and 813 or the electrolytic caps CM807, 812 and 814?)

                                    Comment


                                      #19
                                      Re: No Stdby Light Samsung Ue46d5000

                                      You can lift the VCC pin of the IC and then solder the collector back in place to see if the A5V will stay.
                                      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


                                        #20
                                        Re: No Stdby Light Samsung Ue46d5000

                                        Lifted ICM801 Pin7-LVCC, reconnected collector of QM801 and removed 100 ohm resistor between BL-ON and GND. A5V still stable at 5.26V

                                        I guess I have to order a new FSFR1700XSL now, right?

                                        What exactly is the reason for this IC to fail? Since it's in the backlight circuit I suspect it has nothing to do with a shorted CPU or any other fault on the mainboard, right?

                                        Comment

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