How to connect up two built and tested EasyEDA projects to build a complete replacement 5VDC and 9VAC power supply for the Commodore 64. The design uses the EasyEDA Automotive 12V to USB 5V 2A output power adapter and Precision Commodore 64 Computer Saver PSU overvoltage protection PCBs connected together with a 115V + 115V to 9V + 9V mains transformer, a pair of bridge rectifiers, two 4700uF 25V electrolytic capacitors, two fuses and a mains switch. Both the 5V DC output and the 9V AC outputs are overvoltage protected at 5.7V DC and approximately +/-15V peak AC respectively. The overvoltage limits can be adjusted by changing resistor values in the relevant circuits. The 5V output is overcurrent protected in the hardware of the 5V supply. This overcurrent protection is self resetting. The 9VAC output is overcurrent protected using a 2A fuse. The mains input is fuse protected. The mains transformer primaries are shown connected in series for use on 230V 50Hz - 60Hz mains. Connecting the primaries in parallel (in phase) allows the circuit to be run using 115V 50Hz - 60Hz mains. * For information about the individual EasyEDA projects that this power supply is built from, please see: Automotive 12V to USB 5V 2A output power adapter: https://easyeda.com/example/Automotive_12V_to_USB_5V_2A_output_power_adapter_-L1xrlfxrJ The EasyEDA Precision Commodore 64 Computer Saver PSU overvoltage protection circuit: https://easyeda.com/example/The_EasyEDA_Precision_Commodore_64_Computer_Saver_PSU_overvoltage_protection_circuit-G3pLJ5Paw Note that the overvoltage protection circuit design has been built and successfully tested as part of the Automotive 12V to USB 5V 2A output power adapter.