One of the three power sources was down for testing and maintenance at the time of the episode. The second power source failed unexpectedly. When technicians attempted to bring the third power source on-line, a faulty circuit board in Critical Power Panel failed, preventing power from being restored. (#1) The reason for these failures appears to be examples of problems with aged computers being used for air-traffic control. (#2)

All radar and radio communications at Oakland Center were shut down as the result of a 45-minute power outage. All radar screens went dark and all radio communications were cut off. Lights and telephones were unaffected. It took 45 minutes to restore radio and the backup DARC (direct access radar channel) radar system and it was more than an hour before the NAS computerized radar was restored. (#1)
The center lost all radar and radio contact with airborne planes within an 18-million square-mile area. (#2)