Raspberry Pi 500: I've tried to add a real time clock battery! surprised! I've been surprised!
Also watch:    • Raspberry Pi 500: How it works? Undocument...  

General hardware application information videos for all Raspberry Pis:

The missing element identified: I've just measured the missing element (marked with "?" (question mark) on the video on Raspberry Pi 5 with 16 GB RAM and it turns out to be 75 ohm resistor. I'm sure it's a better choice then a 0 ohm resistor, because it also limits the battery current.

How to mount an external antenna:    • Adding an external antenna to Raspberry Pi...  
How to mount an external power on button:    • Adding an external power button to Raspber...  
Is Raspberry Pi power on button safe?:    • Is Raspberry Pi 5's Power On Button Safe?!  
How to protect your Raspberry Pi against unwanted power on after a power outage:    • Raspberry Pi 5 Wi-Fi Lock and Power On Man...