Vizio TV E470VL SMPS Flucuation Output Voltage

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  • dholley
    Mr. Blinky
    • Jan 2022
    • 87
    • USA

    #21
    Re: Vizio TV SMPS Flucuation Output Voltage

    Regarding R102, testing on side closest to filter capacitors voltage is 169, testing on side closest to IC voltage fluctuates between 79 and 112 volts . Testing at pin 3 of IC which I think is VCC voltage fluctuates between 9 and 11 volts

    Comment

    • R_J
      Badcaps Legend
      • Jun 2012
      • 9534
      • Canada

      #22
      Re: Vizio TV SMPS Flucuation Output Voltage

      what about the voltage on D102?

      Comment

      • dholley
        Mr. Blinky
        • Jan 2022
        • 87
        • USA

        #23
        Re: Vizio TV SMPS Flucuation Output Voltage

        D102 testing bar / striped side fluctuates between 8 and 9 volts

        Comment

        • R_J
          Badcaps Legend
          • Jun 2012
          • 9534
          • Canada

          #24
          Re: Vizio TV SMPS Flucuation Output Voltage

          Originally posted by dholley
          I just measured, there is NO 5 volt or 12 output. The 5 volt was fluctuating from 3 to 4 volts but is now 0 volts. The big capacitors were at 167 volts they are now at 171 volts. I don't know what happened.
          Are you getting anything on the 5 volt line or is it still 0 volts? If it is 0 volts I suspect the u101 is bad and not switching at all.

          Comment

          • dholley
            Mr. Blinky
            • Jan 2022
            • 87
            • USA

            #25
            Re: Vizio TV SMPS Flucuation Output Voltage

            It is now fluctuating around 4 volts

            Comment

            • dholley
              Mr. Blinky
              • Jan 2022
              • 87
              • USA

              #26
              Re: Vizio TV SMPS Flucuation Output Voltage

              I appreciate your help RJ. I’m signing off for tonight, but will be happy to provide any additional information in the morning. Thank you!!!

              Comment

              • R_J
                Badcaps Legend
                • Jun 2012
                • 9534
                • Canada

                #27
                Re: Vizio TV SMPS Flucuation Output Voltage

                If you are getting around 4v on the secondary, you should be getting around 18v on D102. Check that feedback winding on the transformer, check R105, Check D102. If these parts are good then either C104 is bad and not charging

                That feedback circuit also supplies Q101 collector which is a regulator/switch that supplies vcc2 (on its emitter) to the pfc ic U601
                Last edited by R_J; 01-20-2022, 10:01 PM.

                Comment

                • dholley
                  Mr. Blinky
                  • Jan 2022
                  • 87
                  • USA

                  #28
                  Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                  1. Can you tell me how to test the feedback winding on the transformer?
                  2. R105 is 10.01 ohms tested in circuit
                  3. D102 is fluctuating between 8 - 9 volts
                  4. C104 - with my ESR meter is says it is a good cap with low esr

                  Comment

                  • R_J
                    Badcaps Legend
                    • Jun 2012
                    • 9534
                    • Canada

                    #29
                    Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                    Just check the resistance of the winding, it should check around 1Ω. D102 is a diode, use diode test on your meter to check it. The ic shuts down with only 8 volts of vcc

                    Comment

                    • dholley
                      Mr. Blinky
                      • Jan 2022
                      • 87
                      • USA

                      #30
                      Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                      In measuring the transformer from the bottom side of the board, hot side, I put my lead at the end of the transformer leg nearest the IC and put the other lead on the next closest leg, 0.50 ohms, i used the same method on the opposite end 1.0 ohm.

                      D102 - with the diode test of the multi meter, OL one way and 0.536 volt the other

                      Comment

                      • R_J
                        Badcaps Legend
                        • Jun 2012
                        • 9534
                        • Canada

                        #31
                        Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                        The diode check ok, I just had a closer look at the top third picture and C114 looks damaged? or is that black from something else?

                        Comment

                        • dholley
                          Mr. Blinky
                          • Jan 2022
                          • 87
                          • USA

                          #32
                          Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                          Oh my gosh RJ, GREAT JOB!!!!!!!!!!! It is indeed damaged!!!

                          Comment

                          • dholley
                            Mr. Blinky
                            • Jan 2022
                            • 87
                            • USA

                            #33
                            Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                            Pictured attached
                            Attached Files

                            Comment

                            • R_J
                              Badcaps Legend
                              • Jun 2012
                              • 9534
                              • Canada

                              #34
                              Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                              Is the capacity marked on the other side? if it is it is likely a 1kv cap, replace it with a 2kv is recommended

                              Comment

                              • dholley
                                Mr. Blinky
                                • Jan 2022
                                • 87
                                • USA

                                #35
                                Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                                there is no marking on the other side, but it looks like C106 which is near the big filter cap, next to the red transformer. C106 is a 1kv

                                It looks like, C610 not C106

                                C610 is 101k, 1KV. Do you have a replacement recommendation and they are non-polarized correct?
                                Last edited by dholley; 01-21-2022, 01:36 PM. Reason: Correct Cap reference

                                Comment

                                • dholley
                                  Mr. Blinky
                                  • Jan 2022
                                  • 87
                                  • USA

                                  #36
                                  Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                                  have another 101k 1kv on another board, do you think it would be ok to install it and see if that fixes this boad?

                                  Comment

                                  • dholley
                                    Mr. Blinky
                                    • Jan 2022
                                    • 87
                                    • USA

                                    #37
                                    Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                                    the Damaged cap measured approximately 90 PF, if it is a 101k that is pretty close to the right value

                                    Comment

                                    • dholley
                                      Mr. Blinky
                                      • Jan 2022
                                      • 87
                                      • USA

                                      #38
                                      Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                                      I replaced the cap with one from another board. It measured approximately 115 PF. Powered up the board and there is still fluctuation at the output pin and at vcc

                                      Comment

                                      • nomoresonys
                                        Badcaps Legend
                                        • Jan 2013
                                        • 12088
                                        • U.S.

                                        #39
                                        Re: Vizio TV SMPS Flucuation Output Voltage

                                        Originally posted by nomoresonys
                                        Touch up some of those solder joints.
                                        Did you touch up those suspicious joints? just in case you missed the post.

                                        Comment

                                        • dholley
                                          Mr. Blinky
                                          • Jan 2022
                                          • 87
                                          • USA

                                          #40
                                          Re: Vizio TV E470VL SMPS Flucuation Output Voltage

                                          I re-soldered a couple, can you tell me where exactly that needed attention?

                                          Comment

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