Spent 4 hours chasing a phantom short in a 2015 MacBook Air only to find a single grain of solder under the logic board

Has anyone else had a tiny, conductive speck cause a full system failure, and what's your best method for cleaning under BGA chips without an ultrasonic bath?

3 comments

3 Comments

ryan_stone2mo ago

Honestly, that sounds like a lucky find and not the real problem. A single grain usually gets vaporized on power-up and wouldn't cause a persistent short. You probably fixed it by reseating the board and the solder was just sitting there. For cleaning under chips, a good flux wash and some high percentage isopropyl alcohol with a soft brush is all you really need.

holly_craig2mo ago

Remember that time a stray cat hair bridged my RAM slots?

brians277d ago

ryan is probably right about the grain not being the main issue, but I've had a tiny speck of solder short a GPIO pin before and it drove me NUTS for hours. For cleaning under BGA chips without an ultrasound bath, I just use a really good flux wash and then blast it with compressed air from multiple angles. You have to be super thorough and check with a magnifier or the short will come back after you button it up. I've had luck with those cheap dental picks from Amazon to gently work under chips too.