Sentry Bot (Fallout 4)

Sentry Bots are a type of robot found in the Commonwealth and Nuka-World

Characteristics
If engaged in combat for too long, they will eventually enter a cooldown period, blasting steam and flames out of vents on their chest and back while exposing dual fusion cores on their rear. Upon taking terminal damage, the Sentry Bot will initiate a self-destruct sequence. After a few seconds, they will explode. Additionally, the loss of both main weapons will prompt the Sentry Bot to initialize their self-destruct sequence and charge at their target.

Gunner
Reprogrammed by Gunners and have a faded green tint, similar to a Mister Gutsy.

Siege Breaker
A rare, higher leveled stronger variant of the normal Sentry Bot. This type of Sentry Bot has a higher Perception of 9, higher Damage Resistance and Energy Resistance, and 100 more Hit Points.

Gunner Siege Breaker
They will attack anything that isn't a part of the Gunners.

Annihilator Sentry Bot
A tougher and stronger variant of the Sentry Bot, having 150 more Hit Points (totaling 1000), higher Damage Resistance and Energy Resistance and maxed-out Perception. At closer range, the annihilator may switch to its standard sentry weapons.

Gunner Annihilator Sentry Bot
A Gunner variant of the Annihilator Sentry Bot.

Gunner Annihilator Sentry Bot Mk II
Identical to its counterpart except for it programming to kill everything but Gunners.

Combat Sentry Prototype MkIV
An inactive combat sentry prototype MKIV can be found at the robotics disposal ground. Inside the shed near the entrance to the facility, there is a terminal that has a holotape loaded. Initiating the holotape on the terminal activates the Sentry Bot outside, after which it immediately starts to patrol the area.

By ejecting the holotape from the terminal and using it in the player character's Pip-Boy, the Sole Survivor can command the Sentry Bot to go to different locations in the Commonwealth to clear of enemies, after which it will return to the junkyard. However, these locations are limited to nearby military sites. Once activated, the Sole Survivor can interact with it via the Robotics Expert perk to further the commands for it.

Sentry Bot Lament
The Sentry Bot Lament has been modified by the Rust Devils. They may be found accompanying Rust Devil patrols throughout the Commonwealth.

Sentry Bot Reaper
A powerful variant of the Sentry Bot, usually armed with a Gatling laser and a minigun. Due to its heavy armor covering most of its body, it has a high Ballistic damage resistance.

Space Sentry
The Space Sentry was a prototype of the Sentry Bot that was in development before the Great War. It features a white paint scheme with gold accent colors, redesigned armor, leg mounts and wheels, a plastic dome around the head area resembling a helmet as well as new space laser weaponry and Nuka-launchers.

Space Sentry Breaker
A higher leveled stronger variant of the normal Space Sentry Breaker, with higher Perception, Damage Resistance and Energy Resistance, and 100 more Hit Points.

Space Sentry Annihilator
An even further improved version, the Space Sentry Annihilator has a Gatling laser and is able to launch missiles.

Space Sentry Obliterator
Found in the RobCo Battlezone in the Galactic Zone. Only one exists in the Commonwealth.

Locations

 * Northwest of Murkwater construction site and south of Suffolk County Charter School is what appears to be a partially submerged power station, with only the pylon towers above water. If the player character opens a door in the central pylon tower they will see a cinder block wall, with both a graffiti message that reads "YOU LOOK NICE TODAY!" and the same red skull decal used in Halloween decorations just beneath it. A Sentry Bot will spawn on the opposite side of the tiny building and start attacking the player character. Like other Sentry Bots, this Sentry Bot is level-dependent, e.g. at player character level 63 it is an Annihilator Mark II.
 * Directly northeast of Murkwater construction site is a memorial to fallen soldiers, guarded by an initially inactive Sentry Bot.
 * A Sentry Bot will attack the Sole Survivor after they exit the National Guard armory. When the cell resets, the Sentry Bot can be found patrolling the hill around the armory.
 * West of Somerville Place and east of Vault 95 is a Sentry Bot in a cage, guarding a locked storeroom on a slight hill. Picking the lock and entering the storeroom, or attacking this Sentry Bot directly, will activate and release it.
 * One is guarding an abandoned caravan on top of the small hill west of Medford Memorial Hospital.
 * A Sentry Bot will attack at the top of the 35 Court building.
 * An inactive Sentry Bot is present in Hester's Consumer Robotics, which will immediately explode if attacked.
 * There's a chance of a Sentry Bot spawning near the collapsed highway between Easy City Downs and East Boston police station.
 * Two Sentry Bots attack the player character after obtaining the Beryllium agitator in the Mass Fusion building.
 * Two can be found by and on the bridge southeast of Lynn Pier Parking, there are also an Assaultron and Mister Gutsy on a barge after passing the bridge.
 * North of the South Boston military checkpoint, at an unmarked Red Rocket.
 * On the broken highway just west of Flight 1981 at a Gunner outpost.
 * West of Fairline Hill Estates and northeast of Egret Tours Marina. It is locked inside a maglock-locked building and will attack along with two Protectrons if the terminal controlling the door is hacked.
 * Northwest of Coastal cottage is a Gunner outpost on a freeway that's guarded by a Sentry Bot and Assaultron.
 * One patrols the road west of Fort Hagen that leads up to the Fort Hagen satellite array.
 * One roaming the road southwest from ArcJet Systems/southeast from Federal ration stockpile.
 * An inactive Sentry Bot can be found in the Old Robotics section of the Institute. It can be activated with the robotics terminal. It will fight the synths that are on the assembly floor, but will also be hostile to the player character.
 * A non-hostile Sentry Bot is guarding the outside of Cabot House.
 * At the robotics disposal ground there is a Sentry Bot that is deactivated. It can be activated by using the combat sentry proto MK IV holotape that is in a small building nearby.
 * One is found in the Nuka-World Junkyard, under the ledge of garbage that the large red alien saucer is sitting on.
 * A space sentry can be found in the RobCo Battlezone, in the arena after the other smaller robots are defeated.
 * Behind a limestone wall in Vault 88 in the area before the East sector.

Named

 * Ahab (hostile) - encountered inside the Fort Hagen satellite array.
 * Ironsides (non-hostile) - leader/captain of the USS Constitution.
 * Gus (non-hostile) - in a special encounter, Sentry Bot that roams with the small merchant girl, Kat.
 * Porter (non-hostile, destroyed) - part of Jackson's caravan.
 * Sarge (hostile) - encountered inside the armory of The Castle in the quest Old Guns.
 * Startender (hostile/non-hostile) - encountered in the Starlight Interstellar Theater.
 * Combat sentry prototype Mk. IV (non-hostile) - encountered at the Robotics disposal ground.

Automatron
With Automatron installed, the Sole Survivor can build their own Sentry Bots at any robot workbench. They can then be ordered to follow the Survivor like any other companion.

Appearances
Sentry Bots appear in Fallout 4 and its add-ons Automatron and Nuka-World.

Bugs
At the robotics disposal ground, the prototype Sentry Bot MKIV does not move once powered on. There are a number of fixes including fast travel elsewhere and sleep, using the Robotics Expert perk to disable and then reactivate the Sentry Bot, entering the console and click on the Sentry Bot, type, then , and if activated and it still won't move, deactivate either by hacking or the holotape (may say data corrupted), hit or shoot it once, then activate it.