C64 Modding

After having bought a couple of defective Commodore 64s and working on repairing them for some time, I decided that I wanted to have one of my C64s modded in different ways. I had found various descriptions of how people modded their C64s, and wanted to put all this together in one of my own machines.

The first thing I made was a switch for dumping cartridges. This was done according to the description at http://markus.brenner.de/cartridge/, and allows dumping both normal and Ultimax cartridges.

In one of my defective C64s there was a reset-switch on the right side of the case, which I decided to use as well. Using the service-diagram I found a place where the reset signal was accessible and wired it to the switch (with the other wire to ground, of course).

Then there was the multi-kernal adapter, as described on my C64 ROM page. The adapter allows multiple kernals, selectable by a switch.

Here is a photo of the C64 with the modifications:

Modded C64 circuit board

You can see my kernal ROM adapter (the EPROM has a silver label) and the switch (located above the serial/floppy connector).

The gray cable between the second switch and the cartridge slot is for the cartridge dump mod.

The gray and red wires connect to the reset-switch, which is locate on the right side of the cabinet, just next to the power-switch.

Finally, if you look very closely (which is difficult with this low-resolution image), you can see that the wires connecting the power LED have been replaced. Actually the LED has been replaced as well, with a multi-color one. With a little logic (the black IC mounted on top of some other logic IC in the middle row, 8th from the left), I was able to make the LED light red under normal circumstances (as normal). During floppy activity (actually any serial activity) it flashes purple, while tape activity will make the LED light blue.

Here is an image of what my modded C64 looks like:

Spiff's Modded C64

Above the serial (floppy) cable is the kernal switch. The switch above the cartridge is for dumping. On the right side you can see the (white) reset-button. The image also shows my Retro Replay cartridge.

Last updated: 2006.01.28