Are you guys doing a teardown of this? Or is it too expensive to do so?

It looks like (from pictures) that the Apple TV 4K has a vent on the bottom. I’m wondering if it has an active cooling...

Try unpairing it and repairing it from the computer. If that doesn't fix the problem, bring it to an Apple Genius and see what he/she would say. -Reid

Try bringing it to an Apple Genius and see what they say.

Replace the batteries, then try again.

I don't believe there is. Apple stopped putting them in starting with the iPad 2.

If you didn't use your battery for 2 months than you probably got your battery stuck in a deep sleep. This is what Apple says about storing batteries: "Store it half-charged when you store it long term. If you want to store your device long term, two key factors will affect the overall health of your battery: the environmental temperature and the percentage of charge on the battery when it’s powered down for storage. Therefore, we recommend the following: Do not fully charge or fully discharge your device’s battery — charge it to around 50%. If you store a device when its battery is fully discharged, the battery could fall into a deep discharge state, which renders it incapable of holding a charge. Conversely, if you store it fully charged for an extended period of time, the battery may lose some capacity, leading to shorter battery life. Power down the device to avoid additional battery use. Place your device in a cool, moisture-free environment that’s less than 90° F (32° C). If you plan to store your...

The exact same thing happened to my iPhone 5c. It was very hot and made random buzzing sounds and noises. Unfortunately there is nothing to do about it, as I brought mine to the Apple Store and they said it was broken and couldn't be repaired.

Make sure you're using a charger that has an output that matches the input on the phone. The output is usually 5 volts. If you have a 5 volt adapter and it still doesn't charge try a different USB or adapter and if it still doesn't charge try a different outlet and if it still doesn't charge try bringing the phone to Microsoft.

Give it another day -- phones do that sometimes. If tomorrow it does the same thing lmk. -- thereidfleish

I think you would have to go to the Apple Store and ask them to figure it out, because the phone may have shut off because it detects someone tampering and adding new parts to it. A similar Thing happened to my phone. The screen on my iPhone 5c broke off and when I charged it, the phone got abnormally hot like you said. My 5c also was going erratic after the screen detached (it vibrated randomly and make random sounds without me touching it). So bring it to an Apple Store and lmk how it went. - thereidfleish