Author Topic: White Powder/Residue on Board and Solder Joints  (Read 833 times)

Offline Gary

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White Powder/Residue on Board and Solder Joints
« on: March 06, 2018, 10:53:01 PM »
This question isn't specific to the F16v1, but perhaps more about solder joints.

When taking apart my display, I noticed that one of my F16v1 Controllers has some white residue in a few places, namely where the pixel string connect, and some spots on where the RJ45 connectors are. I figured that is has something to do with some snow blowing into the marine battery box. None of my other controllers had the same issue, although the controller in question is exposed to higher winds.

Looking at the bottom of the board, most of the the solder joints have a white powder/residue on them. It scrapes off pretty easily with a fingernail. I did notice a strange trail of residue as well. I've had a earthworms and slugs get into my controller boxes in the past, but it seems weird that the trail of residue is the same as the stuff on the solder joints.

What's the white stuff?

Offline AAH

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Re: White Powder/Residue on Board and Solder Joints
« Reply #1 on: March 07, 2018, 04:47:10 AM »
What that is is some odd effect from the flux residue from the soldering process and it looks to me like there has been exposure to moisture for it to look like that. The flux residue can be cleaned off with a toothbrush and either flux cleaner spray, isopropyl alcohol or methylated spirits if the 1st 2 aren't available.

Offline Todd

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Re: White Powder/Residue on Board and Solder Joints
« Reply #2 on: March 07, 2018, 05:56:48 AM »
I agree, looks like a moisture issue. Hopefully it didn't damage the board. How are the sockets where the chips plug into? Make sure there is no corrosion in there.

Some aerosol electrical contact cleaner should help to get under the port sockets to clean that area.
Todd L.
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Falcon F16V3 F48, FPP, X-Lights, LOR, Pi 3B

Offline JonB256

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Re: White Powder/Residue on Board and Solder Joints
« Reply #3 on: March 07, 2018, 07:50:53 AM »
I've seen that on boards before. All had been subject to high humidity or even liquid contact.
It is flux residue. If the moisture has no salt or mineral content, it is pretty much harmless.

Looking at your pictures, I see no indication of current tracking or damage. The solder joints still look good.
Clean as described with a stiff toothbrush and alcohol. It won't happen again.


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