Announcement

Collapse
No announcement yet.

Samsung LN-T3242H power supply

Collapse
X
Collapse
 
  • Page of 2
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 template Next
    #1

    Samsung LN-T3242H power supply

    Hi,
    I have a samsung LN-T3242H that keeps blowing the fuse on the power supply board. the power supply board is model BN44-00192A. nothing on the board has any visible sign of damage. does anyone have an idea of where to start troubleshooting? Thanks!
    Attached Files
    Tags: None
    #2
    Re: Samsung LN-T3242H power supply

    Originally posted by zachn View Post
    Hi,
    nothing on the board has any visible sign of damage. does anyone have an idea of where to start troubleshooting?
    1) What is that stuff on the VX801 component?

    2) Check BD801S for shorts using ohms. Number the pins 1-4. With power off and lcd unplugged check 1-2, 1-3, 1-4, 2-3, 2-4, and 3-4. If any reading is less than 30 ohms, it suggests a shorted bridge rectifier.
    --- begin sig file ---

    If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

    We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

    Please do not post inline and offsite as they slow down the loading of pages.

    --- end sig file ---

    Comment

      #3
      Re: Samsung LN-T3242H power supply

      thanks for the reply!

      1. that is some glue on VX801, i had swapped that part with a know good board to see if anything changed.

      2. i will test the rectifier and post my findings! thanks

      Comment

        #4
        Re: Samsung LN-T3242H power supply

        should i remove the rectifier from the board for testing?

        Comment

          #5
          Re: Samsung LN-T3242H power supply

          Originally posted by zachn View Post
          should i remove the rectifier from the board for testing?
          You can test it "in circuit". If the readings are under 30 ohms, then desolder to verify.
          --- begin sig file ---

          If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

          We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

          Please do not post inline and offsite as they slow down the loading of pages.

          --- end sig file ---

          Comment

            #6
            Re: Samsung LN-T3242H power supply

            Check the FETs and replace the caps. I worked on one of these a few months ago and the caps were splitting at the top.

            Comment

              #7
              Re: Samsung LN-T3242H power supply

              I tested the rectifier and there was a short between the 1-4 pins. I removed the part and tested again but it tested good. the short is somewhere else on the board. I suspect the part QHAD01216 is where the short is. How do I properly test that component?

              Comment

                #8
                Re: Samsung LN-T3242H power supply

                What is that part? (I don't have my maual handy). If it is a FET, remove it from the board and test again. Most of these switching supplies use a pair of FETs. If one is bad, so is the other.

                Comment

                  #9
                  Re: Samsung LN-T3242H power supply

                  Originally posted by zachn View Post
                  I tested the rectifier and there was a short between the 1-4 pins. I removed the part and tested again but it tested good.
                  What reading did you get out of circuit for pins 1-4?
                  --- begin sig file ---

                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                  We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                  Please do not post inline and offsite as they slow down the loading of pages.

                  --- end sig file ---

                  Comment

                    #10
                    Re: Samsung LN-T3242H power supply

                    pin 1-4 out of circuit was open. can you help me identify the part at RP819? it has 5W0.12ohmJ written on top.

                    Comment

                      #11
                      Re: Samsung LN-T3242H power supply

                      QHAD01216 is the small transformer, i took that off the board and tested for shorts and it looked good.

                      Comment

                        #12
                        Re: Samsung LN-T3242H power supply

                        Originally posted by zachn View Post
                        pin 1-4 out of circuit was open. can you help me identify the part at RP819? it has 5W0.12ohmJ written on top.
                        I would say that bridge rectifiers, FETs, and diodes would be the most likely candidates causing the fuse to blow.

                        The power FET is QP801S. The diodes are DT805, DT806, DP801, DP8?? (just left of QP801S).

                        Check all these for shorts "in circuit". Again, if you get suspicious readings, remove and retest out of circuit.
                        --- begin sig file ---

                        If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                        We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                        Please do not post inline and offsite as they slow down the loading of pages.

                        --- end sig file ---

                        Comment

                          #13
                          Re: Samsung LN-T3242H power supply

                          Originally posted by zachn View Post
                          pin 1-4 out of circuit was open. can you help me identify the part at RP819? it has 5W0.12ohmJ written on top.
                          That sounds like a .12 ohm 5 Watt resistor. It's probably used to sense current through the main switching FET.

                          PlainBill
                          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                          Comment

                            #14
                            Re: Samsung LN-T3242H power supply

                            You have an excellent clear picture of the component side of the board. Could you post the bottom side picture as well.
                            The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

                            Comment

                              #15
                              Re: Samsung LN-T3242H power supply

                              Originally posted by zachn View Post
                              pin 1-4 out of circuit was open.
                              If the bridge rectifier is still out of circuit, try tracing the "circuit path" from pin 1 to pin 4 using the soldering pads.

                              That might give a clue as to what is possibly shorted.
                              --- begin sig file ---

                              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                              We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                              Please do not post inline and offsite as they slow down the loading of pages.

                              --- end sig file ---

                              Comment

                                #16
                                Re: Samsung LN-T3242H power supply

                                Originally posted by retiredcaps View Post
                                If the bridge rectifier is still out of circuit, try tracing the "circuit path" from pin 1 to pin 4 using the soldering pads.

                                That might give a clue as to what is possibly shorted.
                                Correct. Odds are it's the main SMPS FET.

                                PlainBill
                                For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                                Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                                Comment

                                  #17
                                  Re: Samsung LN-T3242H power supply

                                  You guys are correct. the FET at QP801S is shorted, once i have a replacement installed i will post an update. Thanks!

                                  Comment

                                    #18
                                    Re: Samsung LN-T3242H power supply

                                    Don't forget to replace the caps also. They will fail soon also.

                                    Comment

                                      #19
                                      Re: Samsung LN-T3242H power supply

                                      Update

                                      I have replaced the FET at QP801S and the board is not shorting or popping the fuse anymore. However the tv does not fully power on, the standby light is on but doesnt power up. where would you recommend checking next?

                                      Comment

                                        #20
                                        Re: Samsung LN-T3242H power supply

                                        Originally posted by zachn View Post
                                        Update

                                        I have replaced the FET at QP801S and the board is not shorting or popping the fuse anymore. However the tv does not fully power on, the standby light is on but doesnt power up. where would you recommend checking next?
                                        The power supply appears to have four output connectors. Typically these connectors have a legend that indicates the function of each pin. You would be looking for a pin labeled something like On , Power on, On/Off, etc. The voltage at that pin would be a good start.

                                        Of course, good pictures of the bottom of the supply would help, as would pictures of the legends.

                                        PlainBill
                                        For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                                        Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                                        Comment

                                        Previous 1 2 template Next
                                        Working...
                                        X