- EL DORADO TECHNICAL SERVICES, S. E., is a Puerto Rican partnership formed in 1991. The S. E. continued the corporate business of EL DORADO TECHNICAL SERVICES, INC. It is associated with EL DORADO ENGINEERING CORPORATION, which was formed in 1959 and is still registered in several countries in the Caribbean and South America. EL DORADO has been conducting business in Puerto Rico and the Caribbean ...www.eldoradotechnical.com