wassup yall, kestrel here :3

The important parts for writing in most cases are the motherboard, processors, RAM, hard drive, and personality chip.

Motherboard

The motherboard is typically the 'base' all the other important parts connect to! It's a big circuit board with a lot of connection points. That's pretty much the start and end of it.

If you wanna get a little more in-depth, the motherboard is also home to a smaller chip, which is referred to by a lot of different names. This chip contains the very basics like system time/date and BIOS settings. (Note: BIOS is sort of the brain stem of the computer, it tells the computer how to access and understand keyboard and mouse inputs and start the operating system.) This chip is powered by a button-cell battery attached to the motherboard. If that battery fails, the chip can't keep count of the time and date, but the other things it handles shouldn't be affected-- by the time the computer needs to access those settings, it's on and routing power to the chip. All this isn't super important to understanding the motherboard, actually, so I better move on.

The motherboard, like pretty much any other part of the computer, is totally replaceable! I've seen several instances in fics where someone's motherboard gets damaged and as a result the character is afflicted with a permanent disability. I absolutely love disability rep in fic, but a motherboard isn't an irreplaceable component and there isn't a lot it can do when broken besides mess up connections with the rest of the body. Considering breaking it would also interfere with the connections between the various 'brain' components, it would probably just flat-out KO them (which to be fair, could totally fry something important).

Processors

I'll be honest, this part isn't one I have an amazing grasp on. What I can tell you is that the processor handles all the instructions from hardware and software, turning input (keyboard strokes, mouse movement/clicks, etc) into output (visuals on the screen, sound, etc). It doesn't contain anything itself, it just points the signals in the right directions.

There are loads of different types of processors, and some are specialized for different things. The ones you are most likely to be familiar with are the CPU (which handles most general tasks) and the GPU (which is specialized for graphics).

Keep in mind that a processor core can only do one operation at a time, they just do it really really fast! Even me typing a word into this draft takes many many different operations happening in sequence. Most modern processors have more than one core so they can do multiple calculations at once.

I've heard of 1, 2, 4, and 8-core processors but there are probably processors out there with more. Given we're talking about sentient animatronics here I'd say it's perfectly fair to give them more cores or just straight up multiple processors. (If you ask me, multiple processors is more plausible and cost-effective, it'd be easier for Fazbear to buy multiple of something easily found on the market than custom-make extra high tech processors).

Like the motherboard, the processors hold nothing essential to an animatronic's being, and are totally replaceable!

RAM

RAM, or Random Access Memory, is to computers what working memory is to us! It's the memory the computer's actively working with, like programs that are currently running and files that are currently open.

For example, let's say you open up a spreadsheet. You're pulling that spreadsheet from long-term memory (hard drive) to working/short-term memory (RAM), making changes, and then saving those changes back to the hard drive.

See above notes on replaceability. RAM does not hold permanent memory!

Hard Drive

The hard drive, to continue the analogy from above, is long-term memory! Hard drives come in a lot of different forms, from big boxes containing what looks like discs to sticks that look kind of like RAM but the long way. Though it's not recommended, you can theoretically use this memory like RAM, but it'd be a whole lot slower.

Basically, RAM is designed to quickly access stuff but not hold onto it, and the hard drive can hold onto stuff but doesn't retrieve stored things as quickly. (Note: Keep in mind that "slow" in the computer world is like. Milliseconds.)

The hard drive is where the operating system (the software that acts as a base for everything else happening on the computer) lives, as well as all the other files and programs on your computer. This is a part that isn't easy to replace. You'd have to carefully transfer everything on it to a new hard drive first.

If you damage this, it's gonna mess your DCA up in a big way. In most interpretations, an animatronic basically is their memories. There are ways to recover that data if you're a tech genius who's super duper extra careful and the damage isn't catastrophic, but success is very unlikely.

If you're going a more realistic route, this baby contains pretty much everything a DCA is, but...

Personality Chip

Now, this one ventures more into made-up territory. I can't really come up with an equivalent in a real-world computer. The best I can equate this to is a specialized processor with the capacity for holding memories. Sort of a fusion of the hard drive and CPU?

How this component works is entirely up to interpretation. Maybe it holds all the animatronic's memories and acts as its 'mind' like a real brain. Maybe it just carries the base code that an animatronic's AI starts with. Maybe how it works is not important, you just need something small your Y/N can easily snatch from the DCA's destroyed body so they can smuggle their boys home to rebuild. I won't judge! Fazbear has the technology to create sentient animatronics, it's not out of the realm of possibility that they can make something so tiny contain the entirety of that sentient AI.

Maybe this part is replaceable in a similar way to a hard drive. Maybe it's absolutely irreplaceable and any damage to it is a death sentence. Up to you!

Endoskeleton

There are lots of screenshots floating around of FNAF animatronics' insides, and we got a pretty decent look at some of the DCA's inner workings through Ruin Eclipse.

I had a hard time locating close-ups, but we can get a good look at what goes on with the endoskeleton on Eclipse.

There's solid structure underneath much of the sculpting, but behind the teeth there's a second set of teeth, for some reason. The mask is probably rigid, but the fact that it has metal structure underneath it holding its shape could imply that it's made of a softer material.

Through holes in the arm casing and the mostly missing leg you can see springs coiled around the endoskeleton arms and legs, most likely shock absorbers to accommodate the acrobatic nature of the DCA and protect them from the inevitable high drops that come with giving them a tether to the ceiling.

What goes on with the endoskeleton and the way it moves is largely out of my wheelhouse, and I'm pretty sure FNAF-style endoskeletons aren't realistically functional anyway, but I will say whatever's going on to give the daycare attendants such insane dexterity in the hands must have cost a LOT of money.

Unfortunately, what goes on inside the torso/chest cavity is still not super visible.

So, onto the guesswork!

Oil/Coolant

An animatronic like the DCA is probably going to have oil and coolant lines running throughout. Machinery gets hot, and I'd imagine that's especially true for super advanced animatronics! Every major moving or thinking part is gonna need cooling, and considering the lack of visible vent holes on their casing, liquid coolant running throughout makes sense, at least to me.

Oil or coolant for the optics could be a plausible reason to give them the ability to cry, if you want to go that route!

Speaking of eyes,

Optics

Their eyes are high-tech cameras, and if they're anything like Freddy's, they also possess the ability to scan Pizzaplex guests for information. I'd argue it's even more important for a caretaker bot like the daycare attendant to have those features!

Rays

The rays rest between the main faceplate and the back of the head. They are able to retract with what might be an iris mechanism, considering how they overlap on the model (Note: I traced the rays on my drawing from an actual screenshot of the rays after hiding the rest of the faceplate on the model in Blender).

The rays basically cut the head in half along the sides like burger buns. Working around them to get wires through to the eyes or anything else in the front half of the head is likely a pain. Keep in mind both the rays and face can spin independently!

Misc. Head Components

The head is also going to be home to other sensory components like audial receptors and olfactory sensors (if you want to include that). If you want, for your writing, you could plausibly cram facial movement into the front of the face; it may be flat overall but there is some volume there to work with. The head is also where you're most likely going to find access ports for maintenance and updates. (See: the Fazwrench port on Ruin Eclipse)

There's a lot to fit up there with just what I've mentioned, especially if you look at the rays and the movement mechanisms they imply taking up valuable real estate, but that's okay! I actually don't think the important computing bits (hard drive, processors, what have you) are in the head at all, as strange as that might sound.

The head is the most natural place to assume the thinking bits are located, but for them, it's a comically bad place to put that stuff, given the bendy straw neck and the whole exposed circuit board situation. (Actually, the visible wires sticking out and the breadboards on the back of the head imply that the DCA is more of a prototype, but that's further into theory territory than I'd prefer to go. Who knows, maybe all that stuff is sticking out in the game because whoever's in charge of repair took the head cover off to try and fix them and didn't bother to put it back since they weren't repaired yet.)

This is in contrast to the Glamrock animatronics, who I think do plausibly have the space required to put those components up there, not to mention their heads are much more securely attached. Also, Gregory did steal Freddy's head in one of the endings of Security Breach and Freddy got on just fine like that from the looks of it.

Torso Components

The torso is where I think you're going to find the computing parts of a DCA, the music box, the oil/coolant pumps, the fans, the battery, and so on. I'm probably missing some things, but those are the parts you'll likely be most concerned with if you write about the DCA.

It's miles better than the head in terms of space, but that's not a high bar. Here, you'll find the endoskeleton and the oil/coolant lines and the many many wires needed to connect everything to everything take up a majority of the space. It's also important to keep in mind that the daycare attendant is flexible, so everything in the torso is going to need to be very carefully arranged and secured in a way that won't impede that.

The computing parts (discussed in part 1) are likely contained in something like a black box (used on planes to preserve recorded flight data in the event of a disaster). The AIs Fazbear has made and the technology needed to keep them running independently, entirely contained in a relatively small autonomous body, are incredibly valuable. It's important to keep that investment safe from the elements.

If you're going the 'personality chip contains everything' route (valid! It's good for the plot), I would suggest still having a black box like this for support so a single tiny chip isn't doing all the work to run a sentient AI. Perhaps the personality chip is basically the hard drive, or it stores the essentials and certain key memories, while a secondary hard drive contains redundant and nonessential files. What the personality chip does and doesn't do is up to you! The personality chip by itself is small enough that I feel like it'd be okay to put on the head if you wanted, though it's still a pretty risky spot in my opinion.

Casing

The casing is basically the colorful outer shell that covers up and holds together all the internal organs. I'd interpret this as a thick plastic with a silicon outer coating (to soften the surface up, since they interact directly with children), but I've seen people interpret the casing as all sorts of different materials. A common one I see is that it's just straight up painted metal. Whatever makes most sense to you works!

You're likely going to find touch sensory webs embedded throughout the casing, if your version of the DCA has touch sensors at all. If they do have them, note that connecting those sensor webs to the 'brain' means replacing the casing is also likely going to involve getting some things plugged and/or unplugged. The sensory webs could be attached to a wire you have to plug into the endo first, or maybe there's just a plug sticking directly out of the casing you have to carefully line up instead.

Oh, I almost forgot about the color changing! This can go a lot of different ways, maybe it's color-shifting paint based on temperature, maybe it's some technology embedded in the plastic like the sensory webbing. This is another mystery that I'll leave up to creative interpretation!

Similar concepts apply for the pants, though the idea that the DCA has to plug in their pants somehow is very uncomfortable. I'm gonna say that part is either a temperature color-shift thing or bluetooth fabric and call it a day.

Damaging the DCA

It's not easy to give a disability to a character whose parts can all be replaced and repaired. So, if you can't give your beloved DCA model a permanent disability with most kinds of hardware damage, how can you do it? Through the software, of course!

The thing about being sentient AIs is that they learn, and not always in constructive ways. Perhaps they do receive physical damage elsewhere and have to work around it for a while, so by the time the physical part is fixed, their AI has grown around it like a broken bone growing together wrong. It's like a bad habit on steroids. And it's hard, if not impossible, to break a 'habit' you have no conscious control over. For instance, consider a joint or set of joints sending pain signals because they were left damaged for a long period, and the system learned that those parts are supposed to hurt under pressure. No matter how many times the joints are replaced, it doesn't overwrite that code. This can go for just about any part you wanna break!

Of course, there's also the classic can't afford to repair/replace this part conundrum, or maybe the people around that DCA don't know how to do the repairs.

It's good to remember that every part on an animatronic is intentional! A human being had to make decisions on every component to make the final result fashionable, functional, and cost-effective.