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Thread: What is causing this?

  1. #1
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    Default What is causing this?

    I made up these pixel extenders last year. They are enclosed with adhesive lined heat shrink. I needed to shorten a few and I recall I was having an issue with a couple of extenders. After cutting off the heat shrink I found a couple that looks like they are shorting out. The picture shows what the issue is. The top 2 have this white stuff, whatever you want to call it, on them. It almost looks like oxidation. The bottom one looks clean. Any idea what and why this is happening?

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    Last edited by pmiller; 09-18-2019 at 08:13 PM.

  2. #2
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    Default Re: What is causing this?

    Water can wick long distances, also if the heat shrink is going just over the individual wires and not the outer covering youíll get it wicking between the individual wires.

    I have different ones but the same construction concept and lost a few to moisture.

  3. #3
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  4. #4
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    Default Re: What is causing this?

    Quote Originally Posted by StickyWicket View Post
    Water can wick long distances, also if the heat shrink is going just over the individual wires and not the outer covering youíll get it wicking between the individual wires.

    I have different ones but the same construction concept and lost a few to moisture.
    The adhesive lined heat shrink goes about 1.5-2 inches over the outer covering on each side.

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  5. #5
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    Default Re: What is causing this?

    I agree it looks like moisture. A while back Rob posted (and I believe it was added to the wiki) on how he prepares line drivers.
    Included in his post was this. I have some now and put it on a lot of stuff but no history how good it works.
    https://www.ebay.com/itm/MG-Chemical....c100012.m1985

    In the wiki at other site.
    https://www.diychristmas.org/wiki/in...er/line_driver
    Last edited by rayhjr; 09-18-2019 at 08:48 PM.
    Rayhjr I Love This Stuff!

  6. #6
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    Default Re: What is causing this?

    Thanks bud. I'll have to order that stuff and remake my extenders. 2 of them are really bad because the side with the electronic parts mounted look terrible. I'll just throw them out. I have plenty of replacements.

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  7. #7
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    Default Re: What is causing this?

    Definitely water intrusion. Water + power accellerates corosion. I can even see in my pixels which ones are not so waterproof.
    Last edited by aknflyer; 09-19-2019 at 12:23 AM.

  8. #8
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    Default Re: What is causing this?

    The conformal coating will work to help but another "option" would to be to use dielectric grease on the boards and then glue lined heat shrink. I use that "method" on splices and it has held up for years with no water issues. I find that the grease is easier to get off in case I need to make a change.
    I do also use conformal coating on my controllers (LOR units) which works just as well. It is not hard to work with in case you need to solder anything that is coated with it.

  9. #9
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    Default Re: What is causing this?

    Quote Originally Posted by beeiilll View Post
    The conformal coating will work to help but another "option" would to be to use dielectric grease on the boards and then glue lined heat shrink. I use that "method" on splices and it has held up for years with no water issues. I find that the grease is easier to get off in case I need to make a change.
    I do also use conformal coating on my controllers (LOR units) which works just as well. It is not hard to work with in case you need to solder anything that is coated with it.
    Yes I agree, and at the time I could not find a link to the grease so I searched for the wiki post. In Robs wiki he uses both.
    While we are on the subject, I'm curious how many of you think water gets in or it's condensation. I tend to believe it's the latter. Maybe I will start a new thread on the subject. Just curious.

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  10. #10
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    Default Re: What is causing this?

    I brush liquid electrical tape on the ends of all of my heat shrinks and never had any issues. It may be overkill but in Wisconsin with rain, snow, cold, warm at Christmas time you canít protect enough.


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