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Thread: Installing alternate SMD LEDS on TCS K1D4?

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    Default Installing alternate SMD LEDS on TCS K1D4?

    I have a Kato SD70ACe that uses a TCS K1D4 decoder. A couple years ago I accidentally snapped the front LED off with a screwdriver trying to remove the decoder.
    It was a blessing in disguise though, because the decoder's stock SMD LEDs emit the "cold white" blueish LED glow, which is a total letdown, and I thought about replacing the stock cold white LEDs with warm white ones.


    I have some 3v warm white SMD LEDs, can I just solder these directly onto the front/rear LED pads on the bottom of the decoder, or do I need a resistor to tone down the voltage? And if so, which pad has the positive polarity?

    Metro Red Ln (Metro Red Line)
    Under the streets of Los Angeles

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    Do you have a digital multi-meter? With that you can easily determine the polarity of the pads and the output voltage.

    Also, the instructions for the decoder should -- but perhaps they don't -- have information as to whether a current-limiting resistor is required and the rating.

    Here's a handy calculator: http://www.hebeiltd.com.cn/?p=zz.led...tor.calculator
    Paul Schmidt

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    If all you broke off is the LED, I'm sure there are already resistors on the board. You just need to put back a new one, the problems are going to be getting one with the right specifications and soldering something that small.

    A multi-meter with needle probes should help you determine polarity and voltage of the LED. The whole board being fed by 3.3v is likely, and thus 3v LEDs being right, but it might also be a 1.7v or 2.4v board these days.

    Soldering is going to be fairly difficult. You'll need a needle tip soldering iron. I would probably not use any new solder, just tin the iron tip and wipe it off, and then attempt to reheat what is there while holding your new part with tweezers.

    You could also e-mail TCS, they might tell you the specs of the LED, or even the part number.

    In short, I'm sure it's possible. People repair more compact and complex electronics every day. But if you don't have experience and the right tools doing that it's going to be quite difficult.
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    Leo Bicknell

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    I always cut the smd led and replace with normal one. Just need to dismantle the cab and cut 4mm from plastic light guide. I do it with 24 SD70ACE and the MRC 1960Sound decoder. Just need a clean cut, a sheet of 1200 grit sand paper, I use to polish the plastic guide on a piece of paper, dry, until is shiny like mirror. Work for me.

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    I use fiber optics and light everything. There's not much room ,but it can be done.

    ___________Just do it in Vinyl!__________


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