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Vivitek LT26PL1A wont turn on

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    Vivitek LT26PL1A wont turn on

    This LCD TV may also be the same/similar to Westinghouse LTV32
    Bought new in 2006'ish

    I can operate a soldering iron and have some electronics from my technologist training and can identify a cap, resistor and transformer.

    {have learned empirically that electronics run on magic smoke. I have determined this because anytime I have seen that bit of smoke come out of the device (my first radio when I was a kid) it stopped working. q.e.d.}

    Actual Symptoms-
    won't turn on,
    blue and and yellow LED on at same time (looks white)
    no noise. clicks, flicker when plugged in
    main board shows some signs of liquid at some point.
    Power caps look good to me
    solder joints all looked good- but re-soldered anyway.

    Tried:
    adding source (tv s-video and xbox)
    leaving plugged in for more than a week
    leaving unplugged for more than week
    researching ideas (this website and others)

    removed and re-installed all connectors on main board and power module
    re-soldered all larger contacts on power module (including T1 transformer and C210) (not including small ones similar to fuses)
    tested all fuses (marked with an "o")- appear good - no resistance

    tested for voltage at 12 5 and 5vds contacts (at connector) against ground.
    voltage only at 5vds (standby power). Since it won't turn on that may be why there is no voltage at 5v and 12v connector.

    HELP!
    Not sure what to try next- please direct to a descriptive trouble shooting guide or give suggestions to what to try (and how)

    ps let me know if you want better pictures- these look clearer on my computer but are a bit fuzzy here
    Attached Files

    #2
    Re: Vivitek LT26PL1A wont turn on

    Did some one work on this power supply board before? Picture #3 top right, the big MOSFET has heat sink compound on it but missing the heat sink.
    Check the Voltage on that large big black DC filter cap in the hot side (deadly voltage, so do not touch anything with your hands) when the TV is plugged in but do not turn it on it should have about 165VDC on the legs, then hit the power switch and see if the voltage will go up to around 390~400vdc.
    The PS_ON signal is generated from the main board, that signal will present when you hit the power switch, this control signal will turn on the PFC Voltage booster, 12V, and 24V power supply circuits.
    Attached Files
    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


      #3
      Re: Vivitek LT26PL1A wont turn on

      Thanks budm

      I took off the heat sinks to get a better look at the caps.

      I will test as requested and let you know (and try to keep my hands clear)

      Comment


        #4
        Re: Vivitek LT26PL1A wont turn on

        Use GFI outlet if you can.
        http://s807.photobucket.com/albums/y...t=DSC00073.jpg
        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


          #5
          Re: Vivitek LT26PL1A wont turn on

          That`s a great idea

          ps- Thanks for the pics- your surface mount work station looks like a better setup than my kitchen table. However it does not look as comfy as my couch where I have been sitting with the voltmeter trying to figure out what the heck is going on with the d-mned tv. Clearly this isn`t my day job!
          Last edited by GregK; 09-19-2012, 10:07 PM.

          Comment

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