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    #1

    Taking apart a gv42l and troubleshooting

    Recently I've been "donated" a gv42l from my parents that has a issue. It wont turn on fully and once its on it won't turn off unless you pull the power cable. When I mean it turn on, I mean the screen doesn't come on. The white vizio light comes on and that is about it. I wanted to do some troubleshooting on it but I'm having some issues opening it up. I dont want to damage it so I'm being extra careful. Can anyone point me in the right direction? I have all the right tools:voltmeter, soldering iron, solder, some basic electrical background knowledge.

    Anyways give me a chance guys :P.
    Tags: None
    #2
    Re: Taking apart a gv42l and troubleshooting

    Once you get it apart, take pictures of the insides. I suspect this model has the famous "U33" problem, which is an easy fix.
    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

      #3
      Re: Taking apart a gv42l and troubleshooting

      ya haha. I am having the hardest time getting inside of it. anyone know where I can find a tutorial? To desemble it.

      Comment

        #4
        Re: Taking apart a gv42l and troubleshooting

        The front of the tv is latched on to the back like a computer monitor unfortunatly. Use a popscicle stick or guitar pic, something that won't gouge the plastic to bad.

        Comment

          #5
          Re: Taking apart a gv42l and troubleshooting

          Try one of these:
          http://www.harborfreight.com/automot...kit-95214.html

          Comment

            #6
            Re: Taking apart a gv42l and troubleshooting

            Thanks bill the Popsicle sticks worked great. Cut my hand on the plastic and i think i broke the led visio light on the front. I'll have to fix those later. I finally got her open up and took some initial pics. My camera sucks so forgive me guys. I'm going to assume my problem is the mainboard. So I'll start there.
            Attached Files
            Last edited by Silviyius; 06-10-2012, 08:41 PM.

            Comment

              #7
              Re: Taking apart a gv42l and troubleshooting

              Picture are of little use for troubleshooting - a third of the caps "look" to be leaked - stain on the ends but it might just be the picture.
              Please upload pictures using attachment function when ask for help on the repair
              http://www.badcaps.net/forum/showthread.php?t=39740

              Comment

                #8
                Re: Taking apart a gv42l and troubleshooting

                Sorry about that crapy camera wouldn't focus any further. Here's my phone. I need some advice on a fix for the front light... Its a led but its not really a replaceable part... anyways. I don't really see any leaky caps or bloated on the mainboard or the powersupply.
                Attached Files

                Comment

                  #9
                  Re: Taking apart a gv42l and troubleshooting

                  Does your TV have a U33 regulator?
                  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

                    #10
                    Re: Taking apart a gv42l and troubleshooting

                    well i have 3642-0012-0150 (gc) I hope thats what you mean in the pic haha. If not i need to be educated. XD
                    Attached Files
                    Last edited by Silviyius; 06-11-2012, 11:56 AM.

                    Comment

                      #11
                      Re: Taking apart a gv42l and troubleshooting

                      It doesn't look like it then - anyway these Vizios have a lot of problems with the voltage regulators.

                      Check all the devices similar to DU2. To do this:

                      - Switch TV on and get it into the non functional state
                      - Set your meter to 20 volts DC. Red probe should be in volts/ohms. Black in COM.
                      - Probe each pin, excluding the fat tab at the top, which is connected to the middle pin. Note the voltage on each pin, labelled from 1 thru 3 in a consistent manner on all regulators.
                      - Note down the part # on the device and include it in your post.
                      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: Taking apart a gv42l and troubleshooting

                        u4 pin 1: -3.33v pin 2: 0v pin 3: 1.83v part #: ac 6G9L 17-33L
                        u5 pin 1: -0.41v pin 2: 0v pin 3: 2.70v part #: amc 1117 F0629J
                        u6 pin 1: -3.33v pin 2: 0v pin 3: 1.83v part #: ac 6G9L 17-33L
                        u7 pin 1: -0.55v pin 2: 0v pin 3: 0.85v part #: ac 6F5L 17-18L
                        u8 pin 1: -1.39v pin 2: 0v pin 3: -0.51v part #: ac 6G9L 17-33L
                        u9 pin 1: -0.56v pin 2: 0v pin 3: 0.84v part #: ac 6F5L 17-18L
                        u10 pin 1: -0.56v pin 2: 0v pin 3: 0.84v part #: ac 6F5L 17-18L
                        u16 pin 1: -0.14v pin 2: 0v pin 3: 0.75v part #: ac 6F2L 17-25L
                        DU2 pin 1: -1.30v pin 2: 0v pin 3: -0.48v part #: ac 6G9L 17-33L
                        DU3 pin 1: -0.05v pin 2: 0v pin 3: 0.70v part #: ac 6F2L 17-25L
                        DU4 pin 1: -0.86v pin 2: 0v pin 3: 1.04v part #: amc 1117 F0629J

                        Hopefully I read all these right. I used the settings shown by tom66 on my voltmeter and had my black probe on the fat tab. sorry this took so long also I only have some days off. Can anyone make any sense of these readings? They seem all over the place.
                        Last edited by Silviyius; 06-15-2012, 12:34 AM.

                        Comment

                          #13
                          Re: Taking apart a gv42l and troubleshooting

                          Originally posted by Silviyius View Post
                          Hopefully I read all these right. I used the settings shown by tom66 on my voltmeter and had my black probe on the fat tab.
                          Redo them all with your black probe on a main board ground screw (leave it there for all readings). You should not be getting negative voltages.
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                            #14
                            Re: Taking apart a gv42l and troubleshooting

                            haha thanks XD. *feels stupid*

                            Comment

                              #15
                              Re: Taking apart a gv42l and troubleshooting

                              Originally posted by Silviyius View Post
                              haha thanks XD. *feels stupid*
                              No worries. At least you didn't blow up (some exaggeration on my part) your board with your multimeter like one person trying the measure the large high voltage filter cap did in another thread less than 24 hours ago.
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                              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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                                #16
                                Re: Taking apart a gv42l and troubleshooting

                                u4 pin 1: 0v pin 2: 3.33v pin 3: 5.16v part #: ac 6G9L 17-33L
                                u5 pin 1: 0.23v pin 2: 0.64v pin 3: 3.33v part #: amc 1117 F0629J
                                u6 pin 1: 0v pin 2: 3.33v pin 3: 5.16v part #: ac 6G9L 17-33L
                                u7 pin 1: 0v pin 2: 0.51v pin 3: 1.34v part #: ac 6F5L 17-18L
                                u8 pin 1: 0v pin 2: 1.34v pin 3: 0.84v part #: ac 6G9L 17-33L
                                u9 pin 1: 0v pin 2: 0.51v pin 3: 1.34v part #: ac 6F5L 17-18L
                                u10 pin 1: 0v pin 2: 0.51v pin 3: 1.34v part #: ac 6F5L 17-18L
                                u16 pin 1: 0v pin 2: 0.11v pin 3: 0.84v part #: ac 6F2L 17-25L
                                DU2 pin 1: 0v pin 2: 1.15v pin 3: 0.70v part #: ac 6G9L 17-33L
                                DU3 pin 1: 0v pin 2: 0.03v pin 3: 0.69v part #: ac 6F2L 17-25L
                                DU4 pin 1: 0v pin 2: 0.90v pin 3: 1.94v part #: amc 1117 F0629J

                                there my readings should be right now. u5 is making me worry.

                                Comment

                                  #17
                                  Re: Taking apart a gv42l and troubleshooting

                                  Hello all, I am a NOOB and trying to understand how to check the U33 and, also, where to find a replacement

                                  I finally found the U33 which has 3 legs soldered onto the board and the top. Is there any replacement available for this part?

                                  Thank you much
                                  This Forum absolutely the best and, the most helpful forum I have ever found anywhere. thanks to all the fantastic members here
                                  Help keep these from the landfills

                                  Comment

                                    #18
                                    Re: Taking apart a gv42l and troubleshooting

                                    Originally posted by Silviyius View Post
                                    u5 pin 1: 0.23v pin 2: 0.64v pin 3: 3.33v part #: amc 1117 F0629J
                                    u7 pin 1: 0v pin 2: 0.51v pin 3: 1.34v part #: ac 6F5L 17-18L
                                    u8 pin 1: 0v pin 2: 1.34v pin 3: 0.84v part #: ac 6G9L 17-33L
                                    u9 pin 1: 0v pin 2: 0.51v pin 3: 1.34v part #: ac 6F5L 17-18L
                                    u10 pin 1: 0v pin 2: 0.51v pin 3: 1.34v part #: ac 6F5L 17-18L
                                    u16 pin 1: 0v pin 2: 0.11v pin 3: 0.84v part #: ac 6F2L 17-25L
                                    DU2 pin 1: 0v pin 2: 1.15v pin 3: 0.70v part #: ac 6G9L 17-33L
                                    DU3 pin 1: 0v pin 2: 0.03v pin 3: 0.69v part #: ac 6F2L 17-25L
                                    DU4 pin 1: 0v pin 2: 0.90v pin 3: 1.94v part #: amc 1117 F0629J
                                    The suffix in the part number denotes the correct output voltage. For example, -18 denotes 1.8V should be the correct voltage. Most voltage regulators are +/- 1%.

                                    Since every regulator "after" U5 is way way off, U5 would be a good starting point. Since there is no suffix in U5's part number, that is an adjustable voltage regulator.

                                    Budm explains how it works here ...

                                    https://www.badcaps.net/forum/showpo...4&postcount=65
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                                    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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                                      #19
                                      Re: Taking apart a gv42l and troubleshooting

                                      Originally posted by electronicsurplus View Post
                                      Hello all, I am a NOOB and trying to understand how to check the U33 and, also, where to find a replacement
                                      It doesn't matter if you are new or experienced, one thing we don't like here is multiple cross postings for the same problem. It only confuses people and makes much more work for the regulars who are all unpaid volunteers.

                                      Pick one thread and leave it there.
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                                      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 ---

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                                        #20
                                        Re: Taking apart a gv42l and troubleshooting

                                        Thanks Retiredcaps for the datasheet. I appreciate it. Its late here so I'll have to continue tomorrow. I hope DU4 doesn't give me trouble also.

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