A good architect should lead by example, he/she should be able to fulfil any of the positions within his/her team from wiring the network, and configuring the build process to writing the unit tests. Without a good understanding of the full range of technology an architect is little more than a project manager. It is perfectly acceptable for team members to have more in depth knowledge in their specific areas but it's difficult to imaging how team members can have confidence in their architect if they don't understand the technology. As has been said elsewhere the architect is the interface between the business and the technology team, the architect must understand every aspect to be able to serve the business without having to refer others. Similarly the architect must understand the business in order to drive the team toward their goal of serving the business.