The reasons circuit boards are swapped out instead of being repaired is economics. It cost far less for a new board than to trouble shoot the old board and replace the defective parts. In fact, quality control is to the point with electronics these days that failures are less than 1/1000th of one percent, therefore, the devices are no longer inspected and tested before leaving the factory. They just come off the assembly line, they're packaged and shipped to the distributor. The distributor usually takes care of all warranty problems, advertising, etc... Technology is absolutely amazing, even for old codgers such as myself.

Gary