No one had very high career aspirations for teenager David A. Weston—except for Weston himself. Growing up in London, he scored low on the U.K. national assessment test given to students finishing primary school. The result meant that his next path was either to become a laborer or attend a vocational school to learn a trade.What Weston really wanted to do was to work as a radio and TV repairman. He was fascinated by how the devices worked. He had taught himself to build an AM radio when he was...