It's a resistor array and will be connected to your 3P or kick harness connections. Not fixing it will mean one or more of your buttons may not work.
These connections are supplied externally on the DS multi B board so not as much of an issue.
That's correct. The standard is called USB Power Delivery. I've actually been doing some testing with that.
The issue is that USB-C only has a single power output and a maximum of 5A. So if you use 12v as your input voltage and use a regulator/buck converter to get 5v you still only have a...
The PAL jumper is mostly a sound fix, if it's not in place your sounds and some graphics depending on the game will be messed up.
I believe it connects a high/low address line to the PAL that was not needed on earlier games but once 32mbit ROMs started being used in all sections it became...