The rare KU14194HB C64 Motherboard. Retraced in and imported from SprintLayout.

PCBWay note: Please note that for the following instructions from the designer: "It is necessary to cut a trace above R37 on the bottom side, and add a 1K resistor from R37 up to a via. See the images folder for where to cut and add a resistor. Piggyback a 100nF capacitor over CR1," the customer will need to perform these modifications and installations themselves.

Note:

This PCB is a replica. It includes the mistakes that Commodore made.

It is necessary to cut a trace above R37 on the bottom side, and add a 1K resistor from R37 and up to a via. See the images folder to where to cut and add a resistor.

Piggyback a 100nF capacitor over CR1.

Notice how the main crystal oscillator Y1 body is grounded with a wire.

In later designs 250407 Reb B I think, 4 piggybacked diodes were introduced to protect the serial lines when hotplugging the disc drive. I haven't added these myself, but I see the value of having those. I might add instructions here later on how to add the diodes.

more info can be found here:

https://github.com/bwack/KU-14194HB-RevB-KiCad