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    #1

    Vizio VX32L help, not turning on, no power.

    Hello guys,

    I've enjoyed these forums and have repaired many TVs for friends and family using the information shared, but I have come to a point I need a bit of help.

    I have a Vizio VX32L that is dead, no signs of life, no backlight.

    I've used the measurements from this thread to figure this out :

    https://www.badcaps.net/forum/showth...ighlight=vx32l

    Code:
    Component	SB out	SB in	ON out	ON in	
U10		0	0	2.62	4.99	
U7		0	0	1.24	3.29	
U9		0	0	1.49	3.29	
U33		0	0	3.3	5	
U8		3.3	5	3.3	5.04	
U2		0.12	0	3.33	5	
U4		0	0	3.28	5	
U3 		0		11.93		Pin 1
U3 		0		5.02		Pin 3
U1 		0	?	5	?	Pins 1,3,5,6,7,8
U6 		0	?	1.6	?	Pins 5,6

J1:
   Pin 1      PWR ON (about 3.3V? Mine's 1.7V)
   Pins 2,3,4,5   12V ON
   Pins 6,7,8    GND
   Pins 9,10,11   5V SB

F1: 12V ON
F2: 5V SB
    I measured the output of the power supply and it is providing 5v to the main board.

    If I measure any points on the main board above, I get nothing at all.

    J1, pin1, which is the power on has 0 and should be 3.3.

    J1, Pin 9,10,11 has 5v

    I measured F2 and it has 5v on the left side but not on the other side, a continuity test shows no continuity.

    If I test F1, it has continuity but no measurement (since it's not turned on).

    Can I assume this F1 is the issue, is this a fuse? I've never seen this item so I attached a few pics. It says F3A on it.

    Thanks for any insights.
    Attached Files
    Tags: None
    #2
    Re: Vizio VX32L help, not turning on, no power.

    Originally posted by JohnWp View Post
    I measured F2 and it has 5v on the left side but not on the other side, a continuity test shows no continuity.

    If I test F1, it has continuity but no measurement (since it's not turned on).

    Can I assume this F1 is the issue, is this a fuse? I've never seen this item so I attached a few pics. It says F3A on it.
    A good fuse should measure less than 1.0 Ohms. Turn power off and unplug the TV. Take the resistance measurement. Don't use the continuity feature because some multimeters will "beep" good for continuity if resistance is less than 1800 Ohms.

    F1 and F2 are SMD fuses. F3A, is Fast and 3A is 3 Amperes.

    "F" denotes a fuse on the PCB board. See

    http://en.wikipedia.org/wiki/Electro...e_designations
    Last edited by retiredcaps; 11-24-2011, 01:03 AM.
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      #3
      Re: Vizio VX32L help, not turning on, no power.

      Thank you very much! Especially for the reference designations, that will help me in the future.

      I took the resistance measurement and it does not indicate any resistance, so the fuse must be blown.

      What part would I use to replace this fuse? I was looking at part 125CT-ND from digikey since it's approx 6mm long and 2mm wide :

      http://search.digikey.com/us/en/prod...5CT-ND/2766051

      Would that work?

      Thanks again.

      Comment

        #4
        Re: Vizio VX32L help, not turning on, no power.

        Originally posted by JohnWp View Post
        What part would I use to replace this fuse? I was looking at part 125CT-ND from digikey since it's approx 6mm long and 2mm wide :

        http://search.digikey.com/us/en/prod...5CT-ND/2766051

        Would that work?
        That looks good to me. Just doublecheck the measurements. You might want to order 2 or 3 in case the fuse blows again for some reason.
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          #5
          Re: Vizio VX32L help, not turning on, no power.

          I double checked them and was about to order, but those are backordered until 2012.

          Can I use the following part from digikey, I checked and do have the room for it in the same spot :

          F1169CT-ND

          http://search.digikey.com/scripts/Dk...77546530843096

          Thanks.

          Comment

            #6
            Re: Vizio VX32L help, not turning on, no power.

            Originally posted by JohnWp View Post
            http://search.digikey.com/scripts/Dk...77546530843096
            URL comes back with part not found.

            If you have some old equipment (junk boards, old cd roms, etc), you might find a good SMD fuse.
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              #7
              Re: Vizio VX32L help, not turning on, no power.

              I broke open 3 different cd rom drives with no luck, lol.

              Here's the correct link :

              http://search.digikey.com/us/en/prod...69CT-ND/122777
              Last edited by JohnWp; 11-24-2011, 11:47 PM.

              Comment

                #8
                Re: Vizio VX32L help, not turning on, no power.

                Originally posted by JohnWp View Post
                Here's the correct link :

                http://search.digikey.com/us/en/prod...69CT-ND/122777
                It looks good, but I'm not the one with the measuring tape!

                Some people actual "shoehorn" in a glass fuse, but I think it looks ugly and you should get the right component for a 32 inch TV.

                Again, maybe order a couple in case the fuse blows for some reason.
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                  #9
                  Re: Vizio VX32L help, not turning on, no power.

                  You pointed me towards the dark side!

                  I put in a 3a fast blow bus fuse and the TV comes on.

                  I will buy the correct fuse but it's nice to see it come on.

                  edit :

                  Just tried out the TV and even though it comes on, it does not display anything, nothing happens when I press menu or input, or ch+. I did see on the other thread people with an issue close to that so I'll do some more research.
                  Last edited by JohnWp; 11-25-2011, 05:56 PM.

                  Comment

                    #10
                    Re: Vizio VX32L help, not turning on, no power.

                    Originally posted by JohnWp View Post
                    You pointed me towards the dark side!
                    The dark side would be recommending a solder bridge or a piece of wire like some people have done.

                    Just tried out the TV and even though it comes on, it does not display anything, nothing happens when I press menu or input, or ch+.
                    Doublecheck all your connections. Clean them with alcohol.
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                      #11
                      Re: Vizio VX32L help, not turning on, no power.

                      Edit : I went ahead and cleaned off all the contacts and reseated everything, no change.

                      Also noticed the TV turns itself off after a random amount of time.

                      Edit2 : I think I just screwed up pretty bad, accidentally bridged top two contact on U3, TV turned itself off, now it won't come on at all, it tries to come on for a few seconds but then goes back to standby. Measured F1 and it shows 12v so the board is getting the correct power when turned on, then a few seconds later it drops off and no display.

                      At this point am I better of buying a board?


                      ---
                      I verified all the amc1117 measurements using cadiman' from the other thread :

                      Code:
                      u33 5v in 3.2 out
u2 5v in 3.2 out
u4 5v in 3.2 out
u8 5v in 3.2 out

u7 3.2v in 1.25 out
u9 3.2v in 1.50 out
                      they all seem correct.

                      Not sure where to go from here, any tips on what to check?
                      Last edited by JohnWp; 11-25-2011, 07:02 PM.

                      Comment

                        #12
                        Re: Vizio VX32L help, not turning on, no power.

                        Originally posted by JohnWp View Post
                        Not sure where to go from here, any tips on what to check?
                        1) Post pictures of all your boards individually and then one overall shot so we can see the relationship between them.

                        2) If there is a legend on the power board, take a picture of that too so we can verify the DC voltages.

                        3) What is the power LED doing when this is happening?
                        Last edited by retiredcaps; 11-25-2011, 08:50 PM.
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                          #13
                          Re: Vizio VX32L help, not turning on, no power.

                          Here are the pictures as requested.

                          On the third picture, I have highlighted the area I shorted with the TV on.

                          Right now if you plug the power in, the standby light comes on. After a few presses of the power button the power led will turn on for one second, but no backlights, then go back to standby again and then never come on again with the power button.

                          When the unit is powered up, it does switch to 12V on fuse F1, but then after a few seconds goes down again.

                          Previously the TV did turn on and the backlight came on after replacing fuse F1, but no display, I measured out all the points and all voltages were okay until I shorted it by accident.

                          There is unfortunately no legend anywhere, I used the voltages from the other thread.

                          I've checked the power supply voltages and they are correct, 5V standby, 12V on. 24V is being fed to the back light board. On the back light board, I verified both fuses and they are fine, I verified the power and the board is getting 24V on the fuses, but the back light will not come on.

                          I assume I fried something on the back light board when shorting, but not sure how to proceed to diagnose that other than checking the fuses.

                          Thanks for your time.
                          Attached Files

                          Comment

                            #14
                            Re: Vizio VX32L help, not turning on, no power.

                            On the power board, there is a pin labeled PSON (next to the 12 V rail).

                            1) What is the DC voltage of this pin when the TV is in standby?

                            2) What is the DC voltage of this pin when the TV is turned on?

                            3) What is the DC voltage of this pin when the TV shuts itself down?
                            Last edited by retiredcaps; 11-25-2011, 11:54 PM.
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                              #15
                              Re: Vizio VX32L help, not turning on, no power.

                              4) Just to the left of the glass fuse hack, there is another connector covered in yellow tape. I think that connector goes to the panel board? If yes, there may be more fuses to check.

                              I don't think this will help with the current problem, but you might as well check and take a photo of this board as well. If a fuse is bad on the panel board, you would likely get just a white screen. But then again, since I have never worked on this TV, I can't say for sure.
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                                #16
                                Re: Vizio VX32L help, not turning on, no power.

                                1) 0v
                                2) 3.1v
                                3) 0v
                                Attached Files

                                Comment

                                  #17
                                  Re: Vizio VX32L help, not turning on, no power.

                                  About the only thing I can think of is to recheck your voltage regulators (like in post #1). Report all the numbers and we will take a look.
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                                    #18
                                    Re: Vizio VX32L help, not turning on, no power.

                                    Also check all the fuses again on the main board for continuity or resistance. Most DMM's read resistance along with the continuity beep. I'd check the lcd controller/Tcon board at top center of tv for a fuse also. If you had backlights but no picture, that could be a problem with the tcon. Sometimes it's a bad fuse, sometimes it's something else.

                                    Comment

                                      #19
                                      Re: Vizio VX32L help, not turning on, no power.

                                      Originally posted by rmoody View Post
                                      Most DMM's read resistance along with the continuity beep.
                                      If you use the continuity beep feature, make sure to look at the actual Ohm reading. Some multimeters beep "continuous" for readings less than 1800 Ohms.
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                                        #20
                                        Re: Vizio VX32L help, not turning on, no power.

                                        Sorry it took awhile, I verified all voltages and they are correct.

                                        I also verified the fuses on the main board and the lcd backlight board and they are fine.

                                        I did not find a fuse on the tcon board anywhere.

                                        I found that U3 is not getting any power at all, before the top leg would have 5V and the bottom leg would be 12V (before I shorted those legs)

                                        The TV still exhibits the same behavior, the power light will turn on for a second or two and then after about 5 seconds, the 12v to the mainboard will die and it will go back into standby mode.

                                        I'm starting to think this is a lost cause after I shorted it out.

                                        Comment

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