Mainframe core

The mainframe core is a junk item in Fallout 76.

Characteristics
Completion of the Mission: Countdown quest requires a total of 15 undamaged mainframe cores. These can be obtained in one of two ways: by collecting damaged mainframe cores from the computer consoles in the lower level of Site Alpha, Site Bravo, and Site Charlie, and then repairing them at a tinker's workbench. Alternatively, a small number of undamaged cores can be found scattered in the boxes and shelves that are present within the silos.

In the Nuclear Winter update, mainframe cores can be found in Vault 94 during vault raids, and are used to replace damaged ones in Vault Mission: Dead in the Water.

Crafting
A damaged mainframe core can be repaired for use in the Mission: Countdown quest:

Locations

 * Scattered randomly in the lower level of Site Alpha, Site Bravo, and Site Charlie.
 * In Vault 94 during Vault Mission: Dead in the Water.