When it comes to establishing connections between different layers of a PCB or placement of components, the advantage of laser drilling cannot be overestimated. Laser drilling ensures accuracy even when you need to drill even small holes. It uses concentrated laser energy for PCB laser drilling a hole as opposed to mechanical drilling.
BGA Reballing refers to changing every soldered ball on a grid array circuit. Essentially, a ball grid array circuit is established to make an accurate connection between the PCB & the chip. Very often, it will involve extracting old solder balls and replacing them with new ones.
Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside.