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    Samsung LN32A450C1D Red light

    I have a Samsung LN32A450C1D with just the red light on and does nothing pushing the power button. I thought ok must be bad caps so looking at it all the caps look great so I pulled out the 7 big ones and checked with my ESR70 and all were perfect. I did check voltages and almost nothing on all of them. Fuse is good and no signs of anything hot or cold solder joints. Not sure what to check next.
    Attached Files

    #2
    Re: Samsung LN32A450C1D Red light

    any standby voltage?and for starters ,get rid of that brown glue around some of the components,it will conduct more as it gets older and cause problems
    Last edited by multimeter; 03-14-2014, 12:34 PM.
    fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

    ----------------------------------------------
    please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!

    Comment


      #3
      Re: Samsung LN32A450C1D Red light

      Not sure what one is standby on this connector but the ones marked 12v have nothing and the 2 marked 5.3v only have 1v approx.
      Attached Files

      Comment


        #4
        Re: Samsung LN32A450C1D Red light

        ok,cant quite see them,5.3v is most likely the stb voltage,the 12v for the mainboard,.

        disconnect main board loom,recheck voltages on the 5.3v rails on the power supply,do these re-appear?
        fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

        ----------------------------------------------
        please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!

        Comment


          #5
          Re: Samsung LN32A450C1D Red light

          Think this is the schematic:


          5.3V is generated by LM2576-ADJ (ICM856), a buck converter IC, from 24V rail.

          Check-
          pin 1: input voltage, around 24V.
          pin 2: output switch node, approx 5.3V
          pin 4: adjust, approx 1.25V

          Also check pin 2 to ground for shorts, could be bad DM857
          If input voltage present, but no output and DM857 not shorted suspect bad ICM856
          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


            #6
            Re: Samsung LN32A450C1D Red light

            tom66, you need to dumb it down a bit for me I have noware near your smarts. I can not get a prob in to check DM857 and I do not see ICM856 unless it's on the bottom of the board. Should I pull DM857 out of circuit and test??

            Comment


              #7
              Re: Samsung LN32A450C1D Red light

              Originally posted by CraigR View Post
              tom66, you need to dumb it down a bit for me I have noware near your smarts. I can not get a prob in to check DM857 and I do not see ICM856 unless it's on the bottom of the board. Should I pull DM857 out of circuit and test??
              in the pic,i think its next to the large filter cap,on a heatsink,3rd in from the left,

              datasheet here www.hqew.net/datasheet/LM2576$2dADJ-datasheet-pdf-download-209961.html
              Last edited by multimeter; 03-14-2014, 01:42 PM.
              fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

              ----------------------------------------------
              please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!

              Comment


                #8
                Re: Samsung LN32A450C1D Red light

                ICM856 will be mounted on heatsink near main board output connector.
                DM857 will be near it.

                Whenever testing a voltage is suggested but only a single point is given like above the measurement is to be taken with the red probe on the pin and black probe on the ground like the chassis of the TV.

                Diodes are tested on the diode mode of your multimeter in both directions, note the readings you get.
                Last edited by tom66; 03-14-2014, 01:43 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.

                Comment


                  #9
                  Re: Samsung LN32A450C1D Red light

                  Ok found it right next to DM857 and has 5 legs. Hard to see.

                  Comment


                    #10
                    Re: Samsung LN32A450C1D Red light

                    The 3 legs I can reach with my probe show only in the mV range.

                    Comment


                      #11
                      Re: Samsung LN32A450C1D Red light

                      Pin testing may be easier if you solder wires to the pads underneath and test those instead.
                      Last edited by tom66; 03-14-2014, 02:09 PM. Reason: predictive text is alleys Steiner
                      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


                        #12
                        Re: Samsung LN32A450C1D Red light

                        Originally posted by CraigR View Post
                        The 3 legs I can reach with my probe show only in the mV range.
                        pin #1 is the VCC pin,check for input voltage
                        fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

                        ----------------------------------------------
                        please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!

                        Comment


                          #13
                          Re: Samsung LN32A450C1D Red light

                          OK will pull board and solder on some test wires.

                          Comment


                            #14
                            Re: Samsung LN32A450C1D Red light

                            On DM857 I have 1v on the center leg and on MV on the other 2 legs.

                            Comment


                              #15
                              Re: Samsung LN32A450C1D Red light

                              Originally posted by CraigR View Post
                              On DM857 I have 1v on the center leg and on MV on the other 2 legs.
                              number pins 1-2-3

                              its a 3 legged duel diode

                              diode test on meter

                              measure pins 1-2 reading?

                              measure pins 2-1 reading?

                              measure pins 2-3 reading?

                              measure pins 3-2 reading?
                              fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

                              ----------------------------------------------
                              please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!

                              Comment


                                #16
                                Re: Samsung LN32A450C1D Red light

                                And on the 2 legs of ICM856 I have 1V and the other in mV range.

                                Comment


                                  #17
                                  Re: Samsung LN32A450C1D Red light

                                  Which two legs?
                                  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


                                    #18
                                    Re: Samsung LN32A450C1D Red light

                                    1-2 =144 2-1=ol 2-3=153 3-2=OL


                                    2 legs closest to heat sink.

                                    Comment


                                      #19
                                      Re: Samsung LN32A450C1D Red light

                                      diode seems OK so ICM856 is the prime suspect, but need those voltages on 1,2 and 4 to be sure.
                                      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


                                        #20
                                        Re: Samsung LN32A450C1D Red light

                                        OK give me a min to put this back in the will tap ICM856 voltages.

                                        Comment

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