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Westinghouse VR-4085DF (version TW-61951-A040D)

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    Westinghouse VR-4085DF (version TW-61951-A040D)

    Hello,

    I have a Westinghouse VR-4085DF. I've torn it open, expecting to find some bad caps, but didn't. I now suspect the inverter and just wanted confirmation if my logic was sound.

    The TV powers on, the main logo is displayed, and if you hit menu real quick like, you can see the menu, however, the display dies really quick like. The power light is still blue, I can still turn the television off, etc.

    If I hit menu again, I see the menu screen go away. So I know it's something relating with backlighting....

    The bad news is the inverter part number is LS-1940T04001-064-S060078-15979-03

    ShopJimmy doesn't carry it, they used to, they're not planning on getting anymore, and they cannot recommend a substitute. I imagine this is probably because the inverter's design is flawed.

    I could probably purchase the same inverter off ebay or some place, but if the design is flawed, it'll just happen all over again.

    Do you guys agree that I'm on the right track here, thinking it's a bad inverter? Or could it be something else?


    The connector pin that connects it goes to the logic board and the power board. Tracing it, from the PSU, I see ~24.50VDC going into the inverter at all times, even after I loose display.

    From the logic board, I see ~4.81VDC and ~3.35VDC going into it at all times, even after it loses power.

    There's test pads by the mini-transformers that leave the inverter board. I test them, and ~0VDC after we lose power. I can't seem to test them quick enough to see what they read before hand. I suspect maybe one of them might be bad or something.

    I can provide pictures if anyone wants them. But to me, it seems like it's definitely an inverter issue. The voltage going in doesn't change, but the voltage leaving does.
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

    #2
    Re: Westinghouse VR-4085DF (version TW-61951-A040D)

    Yes it does appear to be n inverter/backlight issue.

    Comment


      #3
      Re: Westinghouse VR-4085DF (version TW-61951-A040D)

      Originally posted by Andrew F. Ali View Post
      Yes it does appear to be n inverter/backlight issue.
      Thank you. It is too bad ShopJimmy couldn't recommend a newer / alternative part.

      I'm afraid I'm just going to have to find a source for the same possibly faulty designed product.
      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

      Comment


        #4
        Re: Westinghouse VR-4085DF (version TW-61951-A040D)

        Inverter has been replaced. Same issue. Going to have to assume bad CCFL bulb(s) now.

        Inverter has ten tabs. Does that mean ten bulbs? Probably should replace them all at this point, right?

        It's just a little odd that the main display turns on for a few seconds, then goes dark. Almost wondered if the brightness was turned all the way down, but not sure how to check that. If there was a a pin labeled DIM, I'd throw a voltmeter on there and see what it shows, but I don't got any labeling like that.
        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

        Comment


          #5
          Re: Westinghouse VR-4085DF (version TW-61951-A040D)

          I found a Samsung datasheet for the LTA400HM01 board, which gives pinouts for the 14-pin inverter connector, and I believe this document is for a little bit newer LTA400HM01 main board. It mentions LED lights, instead of CCFLs, but the voltages are all the same it seems. The pinout is a _little_ different though.

          For example, the document lists pin 14 as NC, although there is a connection. And the voltages for the 24V all check out, the voltage for Backlight On / Off and Dimming Control seem to be switched, but I'm assuming the pinouts just different.

          I get a 3.3V going to where the sheet lists backlighting control, which shows ON at 2.4VDC - 5.25VDC. The 4.something volt is within that range. Then the sheet shows the dimming control as having a max of 3.3V, which I get on another wire.

          So I'm thinking bad bulbs at this point, unless someone has another suggestion on what to check. If I couldn't see the image with the flashlight, I'd check out the TCON / main board some more.


          SMPS board has pinouts, and they all check out, even the 5V STDBY. If I remember correctly, there should be a 5V going to the inverter, a control signal I believe it's called, to tell the inverters to kick on. I believe that's what that 4.81VDC is....I see that at the inverter board, so I can only think bad CCFLs.
          Last edited by Spork Schivago; 08-06-2018, 05:16 AM.
          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

          Comment


            #6
            Re: Westinghouse VR-4085DF (version TW-61951-A040D)

            That one wire on the inverter measures 5.03VDC until the backlight kicks off, then it measures around 4.7VDC - 4.8VDC. I believe that's the control wire. That should be high enough to keep the backlighting on, shouldn't it?
            -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

            Comment

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