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Fungus Among Us or what the heck is this?

S

Shadow Lord

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So while doing repairs on my 5322 I ran across this:

IMG_9314 (Custom).jpg

IMG_9315 (Custom).jpg

Initially I thought that the jumpers had a white plastic base that was breaking apart but it turns out it is actually a white coating on the jumpers:

IMG_9318 (Custom).jpg

IMG_9317 (Custom).jpg

So what do we have here? Fungus, a baby Crystalline Entity, or something else entirely?
 
I've seen that on different boards in the past, It's probably some sort of sealant used in production.
 
eeguru said:
So what does it taste like? That might narrow it down :)
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Hmmm... Good question. I am happy to forward some to you for "analysis". You should be able to sprinkle it on like salt! Of course if it turns out to taste like Truffles I may have to charge you ;)
 
I like the sealant theory but... it seems to really only occur on the once glossy black headers. There appears to be a little that has fallen off and speckled the area nearby.

So I'd expect that black plastic had a dipped-coating that has dried out or broken down. It appears superficial and while interesting, something that does no damage and can be brushed or blown away.

Maybe it was a coating to keep the plastic from melting so quickly during wave-solder or manufacturing steps.
 
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JDallas said:
So I'd expect that black plastic had a dipped-coating that has dried out or broken down. It appears superficial and while interesting, something that does no damage and can be brushed or blown away.

Maybe it was a coating to keep the plastic from melting so quickly during wave-solder or manufacturing steps.
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My gut feeling is that it's either a coating like that, or it's a breakdown product of the plastic base itself. If it reappears in another 20 years after washing it off, then that would help support my hypothesis.
 
NF6X said:
...or it's a breakdown product of the plastic base itself. If it reappears in another 20 years after washing it off, then that would help support my hypothesis.
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True. Probably of note is the remains of the header plastic now. While obviously dried out, if its a different plastic material core it would make some sense. In other words it might be a two plastic molding.

But I've cut and dug into the plastic of those things too many times over the years... never saw anything suggesting two different plastics in use; it appeared to be a homogeneous single material molding.

Anyhow, let's both check back in 20 years and compare notes. :)
 
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I wouldn't worry about it, I've never noticed any adverse effect's in cleaning it off, It may be a protective coating as JDallas said, Some of the pin headers i've seen have had quite a thick coating of the stuff more like a sealant and others not so thick.

Shadow Lord said:
So is the white stuff how it is supposed to be or is that the sealant breaking down?
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Malc said:
I wouldn't worry about it, I've never noticed any adverse effect's in cleaning it off, It may be a protective coating as JDallas said, Some of the pin headers i've seen have had quite a thick coating of the stuff more like a sealant and others not so thick.
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Well, I cleaned it off as seen in the second set of pictures and looks like no harm is done. The stuff would literally brush away to the touch so no point in trying to preserve it. I just wanted to make sure I am not going to end up in the ICU next week w/ chemical pneumonitis! ;)

I'll f/u in ~20 years with new pictures to see if it returns...
 
Shadow Lord said:
Well, I cleaned it off as seen in the second set of pictures and looks like no harm is done. The stuff would literally brush away to the touch so no point in trying to preserve it. I just wanted to make sure I am not going to end up in the ICU next week w/ chemical pneumonitis! ;)

I'll f/u in ~20 years with new pictures to see if it returns...
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Probably mildew.
 
MikeS said:
Probably mildew.
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...or dried out firmware.

You know... I've heard that those EPROM stickers over the transparent windows are necessary to keep the JMP instructions inside.
 
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