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Winbook 46d1 LCD TV Inverter Problem

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    #1

    Winbook 46d1 LCD TV Inverter Problem

    I have a Winbook 46D1. It does not go into protect. Instead it turns on, shows the logo and stays "on".

    I tested this TV and found that it tries to fire up the lamps a couple of times and quits. The PSU seems to output 12v, 5v, and 24v. The PSU fuse was blown and "replaced". The large 450v cap seems bloated. The large inductor beside it had one wire disconnected and is bent upward. I ghetto soldered it back on and it didn't remedy the situation. Both 24V outputs seem to be running off 1 transistor and there is a place for another one.

    The inverter(s) has several little voltage regulators as shown. One of them outputs only 6v but it does jump up to 24 when the TV tries to fire up the lamps. I've thought about replacing the 1000uf 35v caps and then maybe the big cap. As well as the 6v regulator. They are all marked DA. I cant find a service manual even though the power supply and inverter boards (Samsung) are common to several models.


    Anyone seen this before or have a service manual for a similar tv?

    http://drop.io/jtsuahy

    has the top of the PSU.
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    #2
    Re: Winbook 46d1 LCD TV Inverter Problem

    Originally posted by NxB
    I have a Winbook 46D1. It does not go into protect. Instead it turns on, shows the logo and stays "on".

    I tested this TV and found that it tries to fire up the lamps a couple of times and quits. The PSU seems to output 12v, 5v, and 24v. The PSU fuse was blown and "replaced". The large 450v cap seems bloated. The large inductor beside it had one wire disconnected and is bent upward. I ghetto soldered it back on and it didn't remedy the situation. Both 24V outputs seem to be running off 1 transistor and there is a place for another one.

    The inverter(s) has several little voltage regulators as shown. One of them outputs only 6v but it does jump up to 24 when the TV tries to fire up the lamps. I've thought about replacing the 1000uf 35v caps and then maybe the big cap. As well as the 6v regulator. They are all marked DA. I cant find a service manual even though the power supply and inverter boards (Samsung) are common to several models.


    Anyone seen this before or have a service manual for a similar tv?

    http://drop.io/jtsuahy

    has the top of the PSU.
    Q103 and Q104 aren't voltage regulators, they are transistors. That circuit looks strange. It would be interesting to know where the top pin of Q103 actually goes.

    By your description, this sounds like it could be the 'two seconds to black' problem; do the CCFLs actually light?

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment

      #3
      Re: Winbook 46d1 LCD TV Inverter Problem

      They do light and try to light again. I know Q103 and Q104 are connected to the caps on there and f101.

      Comment

        #4
        Re: Winbook 46d1 LCD TV Inverter Problem

        Originally posted by NxB
        They do light and try to light again. I know Q103 and Q104 are connected to the caps on there and f101.
        Even a guy with cataracts can see that the collectors of Q103 and Q104 are each connected to the power supply through 4 220 ohm resistors in series. That arrangement is odd - it appears designed to dissipate a lot of power (well, more than the individual resistors normally can dissipate). It is also curious that by your readings, base and emitter might be shorted - or are you just rounding the numbers off like I tend to do on a cursory check?

        Now, all of this may be a non-issue. Certainly the fact that the CCFLs come on briefly would say it is. But why are they turning off? And what is with the drive arrangement for the transformers - it appears the primaries are wired in series. There appears to be a different type of transformer to the right, but you haven't shown the entire board.

        PlainBill
        For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

        Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

        Comment

          #5
          Re: Winbook 46d1 LCD TV Inverter Problem

          I did round off the readings. The transistor doesn't seem shorted but I did want to replace it. I just can't identify the component.

          Here are pics of the entire board.

          http://drop.io/n5eha1g

          Comment

            #6
            Re: Winbook 46d1 LCD TV Inverter Problem

            Have you gotten any further with troubleshooting? I have a unit that sounds like it has the exact same issue that you are experiencing and I haven't tore into it that much yet but from what I have noticed it appears that the power supply and mainboard might be OK. It seems like it is possibly an inverter board type problem. There is a 2 wire connector on the upper right of the mainboard (brown and black wires) that I can unplug and when I plug it back in the backlights will come on for a second and I see "TV No Signal" on the top of the screen. What really stinks is that this problem started about a month after the TV was out of warranty. It's going on 4AM and I couldn't sleep so I decided tear into this and this is where I am at so far. I hope to look at it some more later today.

            Comment

              #7
              Re: Winbook 46d1 LCD TV Inverter Problem

              Hello all

              NxB, I was wondering if you (Or anyone) happen to have the part number of the inverter boards for the 46D1?

              Comment

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