DP50747-00 - Symptom Powers on for 3 seconds then protection fault

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  • crepiduse
    Senior Member
    • Nov 2010
    • 69

    #1

    DP50747-00 - Symptom Powers on for 3 seconds then protection fault

    Ok. I have a DP50747 (Sanyo) chassis number 00. I got it for free from a friend when it stopped working. So, it's worth a little to me to fix it if I can under $250 or so.

    The power supply relay clicks off and the circuit goes into power fault protection mode with an error LED of 3. 3 is A12 UVP (undervolt protection).

    I picked up a working LJ44-00132A power supply (same as one in it) and places it in the tv figuring it would be the problem, however the problem still exists. However with the new power supply, if I take off the jumper next to the error led, it will stay on and static comes out of the speakers. no picture though. the error led without the jumper continuously flashes. if I place the jumper back on and turn the tv back on the light will flash 12 times. If I then unplug and wait 1 minute then try again, I am back to 3 flashes A12 UVP error.

    I think the logic board will be the culprit here.... any ideas? I have the FSM available.
  • crepiduse
    Senior Member
    • Nov 2010
    • 69

    #2
    Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

    I replaced the logic and checked all fuses. I now get power for 3secs then 12 blinks on the Main Supply Error LED1.

    There is no ref to what 12 blinks is....... So I am at a loss....

    Comment

    • crepiduse
      Senior Member
      • Nov 2010
      • 69

      #3
      Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

      Does anyone have a FSM on this model? I bought the $5 one and it is incorrect for the DP50747-00......

      Comment

      • crepiduse
        Senior Member
        • Nov 2010
        • 69

        #4
        Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

        Checked all listed voltages and no problems there. All fets test good, all fuses good, and all trails good that I have the ability to test with my equipment. I am beginning to believe an adjustment is out of whack and have had no luck finding the DP50747-00 FSM. Figured I would ask again.

        Comment

        • crepiduse
          Senior Member
          • Nov 2010
          • 69

          #5
          Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

          Decided to work on this one again, replaced power board, and logic board, get 3 flashes A12 UVP.

          Comment

          • cadiman
            Badcaps Veteran
            • Mar 2010
            • 397

            #6
            Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

            Are you working with a Samsung plasma panel?

            You most likely have a y drive or buffer problem or both and you have already replaced too many parts.

            I have worked on some older samsungs and I was able to unplug the y drive and see if the power supply would stay on.

            Find out what panel you have then research the panel, search old posts, etc.

            Logic boards rarely fail.

            Comment

            • crepiduse
              Senior Member
              • Nov 2010
              • 69

              #7
              Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

              I agree that I have replaced too many parts, but I have spent little

              The issue seemed power related as it is 12volt Under Volt Protection.

              If I unplug the y drive it still does the same issue. I have to unplug both y and x.

              It is a samsung panel and there are limited threads here and on the web and much less about the issue I am having. Unfortunately it doesn't seem to be a well worked on model.

              Comment

              • rayrod81
                Badcaps Veteran
                • Oct 2010
                • 205

                #8
                Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                12V failure on a plasma probably means you have a bad main board. These Sanyos have a history of main board failures.

                Comment

                • PlainBill
                  Badcaps Legend
                  • Feb 2009
                  • 7034
                  • USA

                  #9
                  Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                  Originally posted by rayrod81
                  12V failure on a plasma probably means you have a bad main board. These Sanyos have a history of main board failures.
                  That is interesting. Philips has problems with the DC-DC converter on their Small Signal Board. The symptom is an overloaded 12V supply. The repair is actually quite easy.

                  crepiduse, a picture of the main board (top and bottom) would be helpful.

                  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

                  • crepiduse
                    Senior Member
                    • Nov 2010
                    • 69

                    #10
                    Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                    PlainBill, thank you for responding. Which main board? They're the crazy company that labels them all as main. Main Logic, Main Power, Y Main, X Main.....yadda. I will gladly post pics of any you think will help.

                    Comment

                    • PlainBill
                      Badcaps Legend
                      • Feb 2009
                      • 7034
                      • USA

                      #11
                      Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                      Originally posted by crepiduse
                      PlainBill, thank you for responding. Which main board? They're the crazy company that labels them all as main. Main Logic, Main Power, Y Main, X Main.....yadda. I will gladly post pics of any you think will help.
                      The board with the signal input jacks; known variously as the miscellaneous main board, small signal board, etc.

                      I always encourage post an over-all picture of the back TV set with the cover off. That makes it easier to indicate what we are interested in.

                      Note: Attach pictures with 'Manage Attachments'; don't post inline.

                      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

                      • crepiduse
                        Senior Member
                        • Nov 2010
                        • 69

                        #12
                        Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                        Pics
                        Attached Files

                        Comment

                        • PlainBill
                          Badcaps Legend
                          • Feb 2009
                          • 7034
                          • USA

                          #13
                          Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                          Good pictures, but I don't see an obvious problem.

                          One idea (worth every penny you have paid for it), you are looking at an undervoltage error on the 12 Volt line. Where do the 12 volt outputs from the power supply go? If it goes to an audio amplifier, try disconnecting that. If it goes only to the main board see if you can identify where it goes. I would suspect it is used as input power to various voltage regulators.

                          Bill
                          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

                          • crepiduse
                            Senior Member
                            • Nov 2010
                            • 69

                            #14
                            Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                            That is a great idea, and the odd part is all the traces I have found, have the correct voltages

                            Comment

                            • PlainBill
                              Badcaps Legend
                              • Feb 2009
                              • 7034
                              • USA

                              #15
                              Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                              Originally posted by crepiduse
                              That is a great idea, and the odd part is all the traces I have found, have the correct voltages
                              Which would indicate it MIGHT be a detection error.

                              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

                              • crepiduse
                                Senior Member
                                • Nov 2010
                                • 69

                                #16
                                Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                                Ok, and a good way to test that theory?

                                Comment

                                • PlainBill
                                  Badcaps Legend
                                  • Feb 2009
                                  • 7034
                                  • USA

                                  #17
                                  Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                                  Originally posted by crepiduse
                                  Ok, and a good way to test that theory?
                                  Locate the circuit that is generating the problem and verify the 12 Volt line is correct.

                                  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

                                  • CoppellTVRepair
                                    Member
                                    • Dec 2010
                                    • 39

                                    #18
                                    Re: DP50747-00 - Symptom Powers on for 3 seconds then protection fault

                                    If I were you I'd send the power board for test and service here.

                                    Yes I know you've already replaced it, but I still stay on the opinion that this is what needs to be addressed.

                                    To get you a step further I'd try and activate the power board alone to see if it produces all voltages it is supposed to produce; without load from other boards, that is.

                                    if it still fails with an error code...you know I am right.

                                    if it doesn't...well, it gets more complicated , but it also tells you where to look for the trouble - at the 12V load line.

                                    Still doesn't mean the problem is outside of the board...it can only fail under load, for example.

                                    We do offer a repair service for this power, I am pretty certain about that...just find it at www.coppelltvrepair.com ...

                                    Hope this helps.

                                    Again, based on experience, I'd go for a test/service of the power board first.

                                    Comment

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