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Can Water Contamination Cause Failure?
Board Talk
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TranscriptPhil Welcome to Board Talk with Jim Hall and Phil Zarrow of ITM Consulting, the Assembly Brothers Place and Pick coming to you today from the ITM Elegant Ballroom high atop Mount Rialto. We're here to talk about electronic assembly, materials, equipment, components, practices and procedures and maybe some other things. And what exactly are we talking about today, Jim? Jim Well it comes from H.M. We have an operational circuit board that was accidentally exposed to rainwater for a few hours. The circuit board was subsequently dried and has now been operational for 14 months. Is there a greater likelihood of failure at this stage compared to other circuit boards? I assume they mean other circuit boards that haven't been exposed to rain. Phil I guess my first impression is that the key operative thing here is properly dried. We don't know the details, but we'll take H.M.'s word for it that it was an appropriate procedure and it seems to have been effective. Jim I can't think of anything that could have failure mode resulting from water exposure that wouldn't have showed up in 14 months. Assuming there's some regular operation and this isn't an emergency device that sits on the shelf for most of its time. The main thing is that it was dried and if it wasn't dried properly it would have failed pretty quickly I would suspect. The other thing would be contamination. Whatever is going to happen, dendrites or corrosion, it should have happened by now. Let's be honest. Most circuit boards are perfectly able to be water washed. It's very common so there really aren't any problems with water and circuit boards as long as they're clean. But extended exposure, again, you have to dry them out so that when you first turn the things on you don't boil or expand that water too quickly and crack or delaminate something. The 14 months to me is the indicator. If it hasn't failed by now, it's probably just as good as - maybe better. Maybe the rain water dissolved off some bad stuff that had been there before and now it's actually cleaner and less susceptible to corrosive attack. Phil Who knows, maybe HM was an area where they have de-ionized rainwater. You never know about these things. Well hopefully we answered that question. That's our opinion and I suspect there might be some input on this in our comment section. You've been listening to Phil and Jim on Board Talk, the Assembly Brothers. Whatever you do and however you decide to clean off your boards with saponified water or rain water, don't reflow and don't wave solder and don't hand solder like my brother. Jim Don't solder like my brother. |
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