NASA's Through-Hole Workmanship Req (2002)

Every now and again this pops up on a different forum. I wonder how much is actually hand soldered any more vs. pick and place machines with SMT.

Over the years I have seen couple of closeups of various boards on youtube. As electronics is my hobby, I tend to pay attention to this. They all looked hand soldered to me. And the soldering job always looked very, very high quality.

Keep in mind: this stuff has to be as close to perfect as possible because lives depend on it.

Unless you're sending your stuff to space, I suspect you can cut yourself a bit of slack here. :)

Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense), but a quick google revealed quite a bit of study:

https://nepp.nasa.gov/whisker/

I thought they were just one of those low probability items until a Sunday morning when I was running live audio for a church service. Singer was mid verse and BOOOOM! Huge booming sound over speakers startling everyone into nervous laughter. I opened the cable up afterwards and sure enough found these alien crystalline structures growing between the conductors. It had shorted and even the little bit of current in the microphone vaporized about a mm of material.

Really really weird and I'm certain kept some folks up at night over the years.

These are all good rules. Sometimes it can be really hard to tell when a solder is solid. You can get hairline cracks that aren’t visible to the naked eye but cause intermittent problems.