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    Vizio vw37l Amber light only will not power on

    Hi all.

    I am trying to diagnose my visio vw37l

    I have only orange light

    5vdc standby voltage present on output of power supply but no "ps on" signal present at power supply when power button pushed.

    I was reading another thread and they suggested unplugging the inverters (the other two output plugs of power supply i'm assuming) with no change.

    anyone have any ideas on what to test to isolate (seems like main pcb maybe?)

    Two fuses i could find on main pcb by the input cable test fine

    I also have my 5vdc control voltage at switch/button board

    thanks

    scott

    Update--- I unhooked all connectors on power supply and hooked 3vdcto "ps on" input pin, the power supply voltages 12vdc and 24vdc are present on output pins of the 3 p/s connectors. so p/s appears to work when it gets the "on" signal..

    any ideas why the "p/s on" is not coming from main pcb?

    Added pics--- Thanks for the reply
    Attached Files
    Last edited by swwww; 03-07-2013, 09:35 PM.

    #2
    Re: Vizio vw37l Amber light only will not power on

    Post a picture of the set layout of the boards internal. Then post pics of the boards close up, starting with the power board.
    The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

    Comment


      #3
      Re: Vizio vw37l Amber light only will not power on

      I would check all the voltage regulators on the main board, please see the link below my signature on how to check the regulators.
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

      Comment


        #4
        Re: Vizio vw37l Amber light only will not power on

        Tested all the v-regs I could find... Aside from u-3 2nd of the largest two risiding on the right side not having any input power ( i am guessing this part of the board is not active in standby) all looks good except u7 which is in the middle upper center just below connector has input but no output. Doe this mean its bad? I was getting readings i that trust/understand trying to test the resistor and cap in the area.. (Differed from other readings (ohms) i tried to sample from caps in circuit next to similar vregs in area )

        Admittedly I am traveling a smidge beyond my experience level so my apologies if i am saying incorrect methods

        thanks for any help
        Attached Files
        Last edited by swwww; 03-08-2013, 12:07 AM.

        Comment


          #5
          Re: Vizio vw37l Amber light only will not power on

          Can you report all the readings in the format as shown by retiredcap: https://www.badcaps.net/forum/showth...999#post300999

          U33 is usually bad, same for U7.
          Never stop learning
          Basic LCD TV and Monitor troubleshooting guides.
          http://www.badcaps.net/forum/showthr...956#post305956

          Voltage Regulator (LDO) testing:
          http://www.badcaps.net/forum/showthr...999#post300999

          Inverter testing using old CFL:
          http://www.badcaps.net/forum/showthr...er+testing+cfl

          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
          http://s807.photobucket.com/user/budm/library/

          TV Factory reset codes listing:
          http://www.badcaps.net/forum/showthread.php?t=24809

          Comment


            #6
            Re: Vizio vw37l Amber light only will not power on

            u7
            amc1117
            pin1 -0v
            pin2 -.5v
            pin3 -3.36v

            u33 and all other amc1117's i could find were all the same readings
            amc1117
            pin1 -2.1v
            pin2 -3.36v
            pin3 -5.15v

            u10
            1084
            pin1-1.41v
            pin2-2.66v
            pin3-5.15v

            u3
            az7805t
            pin1-0v
            pin2-ov
            pin3-85mv

            thanks again

            scott
            Last edited by swwww; 03-08-2013, 02:16 AM.

            Comment


              #7
              Re: Vizio vw37l Amber light only will not power on

              Originally posted by swwww View Post
              u7
              amc1117
              pin1 -0v
              pin2 -.5v
              pin3 -3.36v

              u3
              7585t
              pin1-0v
              pin2-ov
              pin3-85mv
              U7 pin 2 should be 1.25V DC. Double check your readings.

              Check your part number U3.
              --- 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.

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              Comment


                #8
                Re: Vizio vw37l Amber light only will not power on

                u7 readings are as reported...

                Correction on u3
                az7805t

                I'm not sure why your are saying it should be 1.25v at pin 2 All the rest of the 1117's are as reported pin 2- 3.36v when tested in the same way, same fixed regulator ( I am grounding meter to chassis ground) When grounding to the regulator ground leg The other 1117's give the 1.25 you are referring to (which is 2.1v different) with the exception of u7 which is as reported(w/meter ground on chassis).. there must be a 2.10v ground difference from chassis ground an the 1117's ground legs.

                Could a u7 failure cause this ground potential difference or are the(1117's) supposed to run w/ ground leg 2.1v off chassis ground? (i am assuming what I am calling pin 1 is the ground leg)

                strange how u7 pin 3 is 2.1v lower than the rest of the 117's pin 3s.

                thanks for all your help



                thanks
                Last edited by swwww; 03-08-2013, 03:09 AM.

                Comment


                  #9
                  Re: Vizio vw37l Amber light only will not power on

                  Originally posted by swwww View Post
                  u7 readings are as reported...

                  I'm not sure why your are saying it should be 1.25v at pin 2
                  Have another read through the how to test a voltage regulator guide (especially post#1 and post#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: Vizio vw37l Amber light only will not power on

                    I reviewed it

                    did you read all my previous post....
                    Last edited by swwww; 03-08-2013, 03:21 AM.

                    Comment


                      #11
                      Re: Vizio vw37l Amber light only will not power on

                      looks like U7 has a 3.3V input where the others have a 5V input. Pin 2 of U7 should read right around 1.25V.

                      Comment


                        #12
                        Re: Vizio vw37l Amber light only will not power on

                        Yes, output voltage (pin #2) = pin #1 voltage + 1.25V, as long as regulator has more than ~0.8V between desired output and input.
                        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


                          #13
                          Re: Vizio vw37l Amber light only will not power on

                          Is it just coincidence that the input of u7 is 2.1 v lower than it should be ( which is the same voltage that the other similar 1117s ground legs are reading--2.1v....

                          And why would it be low.. Is that a u7 failure or a indication of associated circuitry failure.

                          Could u7 be shorting 2.1v of its input to ground causing the 2.1v on the other 1117's gound leg?

                          Or as asked in a previous post, is the ground leg supposed to be off zero on these 1117s...

                          thanks

                          Comment


                            #14
                            Re: Vizio vw37l Amber light only will not power on

                            Originally posted by swwww View Post
                            Is it just coincidence that the input of u7 is 2.1 v lower than it should be ( which is the same voltage that the other similar 1117s ground legs are reading--2.1v....
                            Yes. The regulator can be configured to output any voltage and this is determined by the voltage on that pin. All the main regulators put out 3.3V (2.1V + 1.25V), but there's also a 1.25V regulator (U7: 0V + 1.25V), and the failure is with that.

                            Originally posted by swwww View Post
                            And why would it be low.. Is that a u7 failure or a indication of associated circuitry failure.
                            Nobody knows why Vizio have this problem so often, perhaps an instance of "sort by lowest price" on the manufacturer's catalogue, or by accidentally (or deliberately..) buying counterfeit parts. Also, they often run very hot due to being used near their maximum power rating. I have also encountered failed regulators on Samsung and Haier/Bush TVs.

                            Originally posted by swwww View Post
                            Could u7 be shorting 2.1v of its input to ground causing the 2.1v on the other 1117's gound leg?
                            No, each regulator is independent.

                            Originally posted by swwww View Post
                            Or as asked in a previous post, is the ground leg supposed to be off zero on these 1117s...
                            It can be any voltage you like. A 1117 can output anywhere from 1.25V to around 18V, depending on the requirements of the circuit different voltages are used.

                            Replacing U7 should be all that is necessary.
                            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


                              #15
                              Re: Vizio vw37l Amber light only will not power on

                              U7 gets the input voltage from the output of U33. U7 is bad.
                              As shown in post 6, U33 output is 3.36v, THE INPUT OF THE u7 IS 3.36V. If you check out the connection between the output of U33, it will be connected to U7 input pin. Pin 1 (ADJ/ or GND (for fixed regulator) and pin 2 (output pin) will ALWAYS BE 1.25V due to the 1.25V Vref of the regulator.
                              Pin 1 will be grounded for 1117 Fixed regulator, or will have voltage on pin 1 due to resistor network for setting the output voltage for the Adjustable 1117 series.
                              Last edited by budm; 03-08-2013, 11:25 AM.
                              Never stop learning
                              Basic LCD TV and Monitor troubleshooting guides.
                              http://www.badcaps.net/forum/showthr...956#post305956

                              Voltage Regulator (LDO) testing:
                              http://www.badcaps.net/forum/showthr...999#post300999

                              Inverter testing using old CFL:
                              http://www.badcaps.net/forum/showthr...er+testing+cfl

                              Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                              http://s807.photobucket.com/user/budm/library/

                              TV Factory reset codes listing:
                              http://www.badcaps.net/forum/showthread.php?t=24809

                              Comment


                                #16
                                Re: Vizio vw37l Amber light only will not power on

                                Thank you much for all the info . I really appreciate you taking the time to help clear that up

                                Do you think that my assumption of why u-3(the 2nd of the largest two regulators, residing on the upper right corner of board)does not have power input is a correct one?

                                (see my first post) ( i am thinking this part of the board is not active while in standby or is it due to the failure upstream?)


                                thanks much
                                Attached Files
                                Last edited by swwww; 03-08-2013, 12:20 PM.

                                Comment


                                  #17
                                  Re: Vizio vw37l Amber light only will not power on

                                  Yes, that regulator is correctly functioning (as it receives essentially no input, it gives no output.)
                                  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: Vizio vw37l Amber light only will not power on

                                    Ill give u7 a try and see what develops.


                                    not sure i get what you mean

                                    (as it receives essentially no input, it gives no output.) (u3)

                                    so are you are saying no input should not be expected for the conditions ( because of tv not being on) or are you just stating the obvious (no input no output)



                                    Also...

                                    I do not have an air tool... Are the methods I have read regarding hot iron techniques (heating the tab/globing the legs, ect.) viable methods or does anyone have any good methods/links?

                                    thanks

                                    Comment


                                      #19
                                      Re: Vizio vw37l Amber light only will not power on

                                      The best way to get it off is not using hot air. Glob solder across the three main pins, then heat up the tab and those pins alternately. You'll shortly be able to push it off. This video describes it well.

                                      https://www.youtube.com/watch?v=cNFzBJELFoU&t=8m40s
                                      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: Vizio vw37l Amber light only will not power on

                                        I use the same method as Tom, your iron should be 40watts or more with big tip.
                                        Never stop learning
                                        Basic LCD TV and Monitor troubleshooting guides.
                                        http://www.badcaps.net/forum/showthr...956#post305956

                                        Voltage Regulator (LDO) testing:
                                        http://www.badcaps.net/forum/showthr...999#post300999

                                        Inverter testing using old CFL:
                                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                        http://s807.photobucket.com/user/budm/library/

                                        TV Factory reset codes listing:
                                        http://www.badcaps.net/forum/showthread.php?t=24809

                                        Comment

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