Power Supply Connector
The C64 is powered through the power supply connector. The connector of the external power supply must only be plugged in this connector. The power supply provides 5 volt direct current (DC) and 9 volt alternating current (AC). The power supply connector is located next to the power switch and is labeled as CN7 on the motherboard.
The power supply connector is a 7 pin DIN connector (DIN 45329).
|4||-||N/A||5V or Not connected|
|5||+ 5V DC||1.5 A||5 Volt direct current|
|6||9V AC1||1.0 A||9 Volt alternating current phase 1|
|7||9V AC2||1.0 A||9 Volt alternating current phase 2|
It should be possible to load the 5 Volt of the external power supply with at least 1.5 Ampere.
The 9 Volt alternating current (AC) is the reference frequency for the internal clock and - after being rectified - it is used to power the SID chip (9 or 12 Volts), partially also the old version (NMOS) of the VIC-II chip as well as the motor of the Datasette (6 Volts).
The pin assignment has been thoroughly checked (pin 1 is between pin 4 and 6, pin 3 is between pin 5 and 7). You can find different assignments on the internet which are just completely wrong. Nevertheless, we cannot warrant the correctness. The inversion of pin 6 and 7 would have no consequences in case of the alternating current, as well as the inversion of pin 4 (unused) and pin 5 (5 Volt) will only cut the C64 from the current supply if you have the motherboard without these linked (all PCASSY before and including 250407-RevA). If you build your own power supply or if you repair a power supply cable, it is recommended to check everything twice, for "nothing dies as silently as a microprocessor."