Please note that there are images with different numbering on the internet.
The original power supply is known to kill all IC’s on the mainboard of the C64 when it dies, the regulator in the power supply mostly fails and all circuits will get more than the supposed 5 Volts.
Audio / Video Connector
The Joystick ports are connected to CIA 1 in parallel to the keyboard matrix.
To read the direction from the joystick you can read the memory locations 56321/DC01 for port 1 and 56320/DC00 for port 2.
The userport PB0-PB7 is connected to the CIA 2 port B and is controllable by setting the right direction bits in the Data Direction Register Byte (DDRB) on address 56579 ($DD03).
And writing or reading the port on address 56577 ($DD01).
Note, when using the RS-232 functions (open 2,2,2) will change the DDRB.