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    Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

    As said, i have a faulty Samsung PSU (BN44-00427A) PD46B2_BSM

    The main fuse was blown. All other fuses are fine. There is a short between + and - of the bridge rectifier (BD8015). I have removed both of the big coils to see if the short is on primary or secondary: Primary short after bridge rectifier is still present. But there´s also something wrong on the secondary side: e.g. Short over D3601. It´s not the diode....!

    Any advise on this one?

    Thank you for ur help!

    #2
    Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

    Check the MOSFETs for the PFC stage, one is likely short. Post some pictures and we can highlight the PFC stage.
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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      #3
      Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

      Please check at Jimmys They have a nice one

      Edit: D3601 is in the top right corner
      Last edited by Mr_K; 09-30-2012, 10:50 AM.

      Comment


        #4
        Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

        This is an LED set? More and more of these are failing nowadays...

        Check the FETs I've highlighted for shorts; you may have to desolder the PFC ones.

        Depending on the topology, the D3601 -could- appear short even if it is OK. If you want, you can remove it from the circuit to test, but for now I'd say focus on the primary short.
        Attached Files
        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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          #5
          Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

          [accidental double post - please ignore]
          Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
          For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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            #6
            Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

            First of all thank you for your quick support.

            One of the "lower" FETs (10NM60N) has a short. The other one is fine. The two other FETs (mdf9n50) have no pass in any direction. This seems a bit strange to me.
            And there is still a short at the diode. I made a mistake. It´s named D9601 not D3901. The one in the top right corner. The diode itself is fine. Even after removing all the FETs.
            Last edited by Mr_K; 09-30-2012, 12:36 PM.

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              #7
              Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

              Can you highlight the faulty one?

              If the diode itself tests fine out of circuit, then that is probably not a problem. The diode might in parallel with a low-ohm resistor, for example.
              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

              Comment


                #8
                Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                These two. Propably the red one, but im not 100% sure. I may have mixed them while measuring...
                Attached Files
                Last edited by Mr_K; 09-30-2012, 12:59 PM.

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                  #9
                  Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                  They look like they are paralleled; in which case, I'd say one failed would make the other look failed. If possible, remove them from the circuit and test. You should be able to run the set for a couple of minutes with the bad fet removed, as long as it didn't damage anything else.
                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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                    #10
                    Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                    I already removed all the 4 FETs with the results posted above. I´ll try to get some replacement parts tomorrow and check the board.

                    Comment


                      #11
                      Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                      Ok, TV is working with the faulty FET removed. I was not able to find a replacement part today, so I have to order them. It´s 10MN60N May I replace it with a IRFBC40? This one is only capable of 6.2Amps.......

                      Comment


                        #12
                        Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                        I wouldn't recommend it. Closest I can find:
                        http://www.digikey.com/product-detai...APBF-ND/812095
                        (9.2A rating, 0.75 ohm)
                        But NOT insulated! So you will need an isolating mica pad.

                        or http://www.digikey.com/product-detai...-E3-ND/2799082
                        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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                          #13
                          Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                          These are not easy to get for me.... Maybe this one?

                          Comment


                            #14
                            Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                            The current rating is too low and the gate charge isn't specified. You didn't mention your country so I can't make suggestions relevant to you.
                            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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                              #15
                              Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                              Please check Reichelt I would like to order from them.....in germany.

                              Comment


                                #16
                                Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                                Do you not have Farnell or RS in Germany?
                                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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                                  #17
                                  Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                                  We have both of them. But i´d prefer Reichelt (i need to order more parts there) OR RS - not Farnell
                                  Last edited by Mr_K; 10-01-2012, 03:37 PM.

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                                    #18
                                    Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                                    well, RS stock 'em;
                                    http://uk.rs-online.com/web/p/mosfet...633D424F544826
                                    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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                                      #19
                                      Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                                      I recieved my FETs today and another problem shows up. With one FET installed the TV is running fine but as soon as both FETs are installed, the short comes back

                                      Comment


                                        #20
                                        Re: Faulty Samsung PSU (BN44-00427A) PD46B2_BSM

                                        After removing the apparently shorted device does it test shorted out of circuit? Maybe there's a physical short on the circuit board, like a damaged trace or solder bridge.
                                        Last edited by tom66; 10-05-2012, 02:13 PM.
                                        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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