Other Combat Weapons and Equipment (p. 99)
After the first paragraph insert the following new section:
SPECIAL: SHUTTING OFF EQUIPMENT
During the End Phase of any turn, a player may announce that they are powering down a weapon or piece of equipment on a unit they control (or powering up a previously powered-down item). The change must be marked on the unit’s record sheet. A powered-down weapon may not fire, but powered-down weapons and equipment do not explode if they suffer a critical hit. Powered-down electronics do not function, and are not valid targets for anti-radiation missiles.
A powered-down item is still destroyed if it takes a critical hit. Ammunition, fuel, cargo, etc., may not be powered down and explosive ammunition, fuel, or cargo will always explode if it takes a critical hit.
Thanks for your patience on this one.