I was playing ACNL this morning on the train to work, and when I opened a letter from Colton, the screen went black for a second? Both screens (top & bottom) did that for a sec & then things went back to normal.
I've never had this happen before with my 3Ds... I've dropped it once or twice, but not from a great height (from sofa to floor). I think I've had my 3DS for about 2 years now? I got it before X&Y's release.
Were you close to a magnet? That happens to me occasionally whenever I'm too close to my iPad which has a magnetic close. Or your laptop can have something magnetic in it. If it's that short of a time that it went black, I wouldn't worry too much. Your ad card might also be slightly loose maybe? So you could also check that. Make sure to power off before trying to mess with the sd card though.
Er I was inside an underground train, maybe that was it? I've been travelling to work for about 2 weeks now in the same way, and I've never had that happen before so it slightly freaked me out. But yea, it was only about 1 or 2 seconds.
As for my SD card, I've never taken it out, so I didn't check if it was loose. I'll check it @ lunch.
Perhaps it happened because of the side where you were sitting on the train and it passed by a strong magnet? Hmm, I'm not entirely sure though, but if this is the first time that happened since you've had the 3ds, I'm pretty sure you'll be fine. Don't worry too much, but if nothing else back up your stuff just to err on the side of caution.
And no problem^^ I hope everything's fine for you and that doesn't hapoen again.