First was the fundamental electronics courses. If you passed those courses you progressed into the systems work. If you did not have your security clearance you waited. (And did chores in the clinics or mess hall.) If you flunked out you got orders for "BB Stacker" duty in Vietnam. No one wanted 'nam...no one wanted to take the risk.
Our fundamental electronics classroom building. Watched our classes on TV's and then had labs.
Sytem training was at Department of Special Instruments. Detachment offices on the left...classroom warehouse building stretched to the right.
Detachment HQ. Note the "security" split door. You never got in until you had your security clearance. And even then you were lucky to see more than a room or two.