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    #1

    Vizio VX42L - functions fine, but bad colors

    Have my nieces 42" Vizio. She's had it for several years (2007 mfg I believe). Color recently started to go bad.
    Powers on no issues; sound, no issue; just color issues (across input modes). Remote works fine.


    I've done several hours of research. Found the common issue with Vizio's is the U33 and not powering on completely, but that isn't my symptom, and my meter readings indicate the regulator reads ok, based on values I've seen posted here.

    Powersupply readings
    24V lines both read 23.7v
    2nd 24V lines both read 23.7v
    12V lines both read 11.9

    I've looked over the capacitors, all seem to be flat. No noticable bulging and definitely no bleeding of any kind.

    regulator readings
    U7 - 3.29 / 1.27 / 0.03
    U9 - 3.29 / 1.50 / 0.01
    U33- 5.03 / 3.29 / 2.05
    U8 - 5.08 / 3.30 / 2.06
    U2 - 5.04 / 3.30 / 2.06
    U4 - no chip from factory
    U3 - diff style chip 11.82 / 0.01 / 5.01

    I'm not a electrical technician, but I'm very mechanically inclined, and proficient at soldering, and using meters with a little bit of guidance.
    And I love a new challenge!

    Unit powers on just fine, it's just that the colors are not what they should be, washed out kind of, inconsistent, like someone messed with all the custom settings and intentionally threw it way off. I've done the menu reset and tried each of the different modes of input I had available - PC HDMI, HDMI to cable box, and coax to cable box. PC hdmi was best at rendering good colors, but as soon as I played a DVD through the PC dvd drive, colors were bad again.


    Any feedback would be appreciated on what I might be able to test out.

    Tim

    https://www.badcaps.net/forum/attach...1&d=1419903288
    https://www.badcaps.net/forum/attach...1&d=1419903288
    https://www.badcaps.net/forum/attach...1&d=1419903288
    https://www.badcaps.net/forum/attach...1&d=1419903288
    https://www.badcaps.net/forum/attach...1&d=1419903288
    https://www.badcaps.net/forum/attach...1&d=1419903288
    https://www.badcaps.net/forum/attach...1&d=1419903288
    Attached Files
    Last edited by tjsmith999; 12-29-2014, 07:37 PM. Reason: pics
    Tags: None
    #2
    Re: Vizio VX42L - functions fine, but bad colors

    Top left corner of your AUO Optronics t-con board there is an AS-15 chip, see the copper pads under the two cable connectors, test those voltages and report back.

    Comment

      #3
      Re: Vizio VX42L - functions fine, but bad colors

      Originally posted by Shinju View Post
      Top left corner of your AUO Optronics t-con board there is an AS-15 chip, see the copper pads under the two cable connectors, test those voltages and report back.
      Thanks for the quick response Shinju - I grabbed an image off shopjimmy as I couldn't get my resolution high enough - same setup as mine

      https://www.badcaps.net/forum/attach...1&d=1419967122

      Attached image - R28 values, left (closest to R28) to right:
      0.31
      8.40
      3.94
      5.03
      4.87
      6.30
      6.58
      7.76
      7.98
      9.31
      9.42
      10.41
      15.09
      15.33
      Attached Files

      Comment

        #4
        Re: Vizio VX42L - functions fine, but bad colors

        Yes that is a defective AS15-F
        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

          #5
          Re: Vizio VX42L - functions fine, but bad colors

          Placed an order - will be mid-Jan before I get (overseas).

          I'll be sure to post back my (hopefully) success.

          Thanks to both tom66 and Shinju for your quick responses!!!

          Happy New Year to all!

          Comment

            #6
            Re: Vizio VX42L - functions fine, but bad colors

            IOh shoot, I use a seller for those chips here in the states and they have been 100% solid, be warned chips China have been known to to be bad and fail right out of the box.


            I would order from here and install this one and set the Chinese one on a shelf for a future repair if you find another TV with the bad AS-15f chip

            http://www.ebay.com/itm/100-NEW-IC-A...item35cc8fb341

            These guys are just a little more expensive but I don't mind paying for peace of mind, good luck my friend enjoy the new year!

            Comment

              #7
              Re: Vizio VX42L - functions fine, but bad colors

              OK, I got this TV and my HDMI is blurry, colors are messed up. So I can't find what the voltages are suppose to be. From R28 they read
              0.2
              0.475
              3.84
              4.55
              4.82
              6.46
              6.63
              7.77
              7.90
              12.93
              10.08
              10.51
              10.55
              15.58v

              I checked these with the TV on and on HDMI.
              So from these values can you determine if my AS15-F chip is bad?

              Comment

                #8
                Re: Vizio VX42L - functions fine, but bad colors

                Well I ordered the AS15-F chip, not sure if this will fix it. I would think the problem would be on the main board but it doesn't hurt to put a new one on because I guess someday if not already it will go bad.

                Is it possible someone could post the correct voltages for this part? Thank you.

                Comment

                  #9
                  Re: Vizio VX42L - functions fine, but bad colors

                  I dont think it is a matter of "correct" voltages as much as the progression so on yours a 12 followed by 3 10s and then a 15 would indicate a problem
                  Please upload pictures using attachment function when ask for help on the repair
                  http://www.badcaps.net/forum/showthread.php?t=39740

                  Comment

                    #10
                    Re: Vizio VX42L - functions fine, but bad colors

                    Thank you for that confirmation. The information you got must be from experience because I downloaded the service manual and I did not see it in there or did not look hard enough. My voltage and tjsmith999 voltages are so different I couldn't use those to compare.

                    After I put the chip in I will post the voltage readings. Maybe others can use those for comparison.

                    I not only am trying to fix these TVs but I really want to understand everything as well. I am going to guess that I fixed about 50 TVs in the last 6 months so I am serious about this. Sites like this one make it so much easier. Thank you.

                    Comment

                      #11
                      Re: Vizio VX42L - functions fine, but bad colors

                      Sorry it took me so long to get back. Holidays, shipping, business trip, life in general :o)

                      So I tried to replace the as15 chip. I should have practiced a bit more. I bought several. I got the first one on, but no picture. I wasn't the happiest with the soldering job. I have to give you guys that do this a major kudos! I had problems even getting the chip off. I eventually had to flow a bunch of solder on and heat in a circular motion to remove the chip. Got the new one on, but not the easiest to just hit the pins. Some people I saw just flooded and cleaned up with solder wick. I cleaned up what I could but no luck - that was the blank screen.

                      I tried to put the second one on, but messed up the leads off the board.
                      Oh well. It was fun to try.

                      Thanks for all the feedback - I do appreciate the time taken to read and respond.

                      Comment

                        #12
                        Re: Vizio VX42L - functions fine, but bad colors

                        I cut my AS15-F chip off with a dremal, that is the easiest way. Then I remove the legs with the soldering iron. Then I use flux and add solder to all the spots but not a whole lot. Then I put it in place and use a 15w iron. I messed one up already but I got another one to try. I think the trick is to lay the chip on the solder spots and just touch each leg for one second enough to make a connection, if you do it longer you may burn up the chip. And I am only going to do one leg at a time. I will do one leg and then wait a minute before I do another one. Just touch it for a second and no more.

                        Comment

                          #13
                          Re: Vizio VX42L - functions fine, but bad colors

                          OK, well I put another chip in the TV and I was real careful like I stated. I put the solder down first on the board, laid the the chip on it and just touched each leg for a second, looks good. I noticed one leg was not connected to anything and I guess I tore that part off the board but from my pictures it does not seem important. But the TV is not working so maybe it was important. It is pin 42 so if anyone has a picture of a board with the chip off or knows I did a boo boo I would appreciate the comment. I added pictures. So now when the TV turns on the logo turns white and the backlights flash once real fast. So I can't get the voltages of a good working board yet because it is not working. I guess I may have to cut this chip off and try again.
                          Attached Files

                          Comment

                            #14
                            Re: Vizio VX42L - functions fine, but bad colors

                            Update: I am still trying to fix this TV. After trying to fix the T-Con board the TV would not turn on at all. So I ordered another T-Con and now the TV turns on but it looks like there is a window screen over the TV. Lines going right to left and up and down like a window screen. I was wondering if this is the AS-15 chip?

                            I tried to take a picture but it doesn't show up.

                            Comment

                              #15
                              Re: Vizio VX42L - functions fine, but bad colors

                              Probably not - could be a bad LCD panel or the T-con you got is bad.

                              The pad you have removed is a no-connect pad so should not cause problems. However I have found the AS15-F chips to be incredibly fussy and often defective out of the package. I would try a second one, if possible.
                              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

                                #16
                                Re: Vizio VX42L - functions fine, but bad colors

                                OK, I have ordered another chip. This time I have a BGA Rework Station so I will try using it this time. I will update when I have some progress.

                                Comment

                                  #17
                                  Re: Vizio VX42L - functions fine, but bad colors

                                  Is the AS15-F IC and RM5101 IC the same?

                                  Comment

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