The idea of gutting an original Commodore 64 and replacing the motherboard with a Raspberry Pi is far from new. In fact, I have already done it using an old breadbox case (link). However, during the modding process of that machine the case was completely destroyed and it will not be possible to restore it even if I wanted to 🙁 So when I was asked to do the mod all over again, now with the aid of a case friendly 3D printed conversion kit specifically made for modding a Commodore 64 C case with a RasPi, I immediately accepted! I received the 3D prints a few weeks ago from COREi64.com (link) and instantly made a dedicated post on them as they are very well made (link). The 3D conversion kit costs 65$ plus shipping from Canada and they can be ordered in a variety of colors.
I wanted the machine to look just like an original Commodore 64 C on the outside, but with its internals replaced by a Raspberry Pi 3 Model B and the original C64 power supply unit should be used to run the Raspberry Pi. As a little teaser of what to expect, the final mod ended up looking like this – The C64 RetroPie Mod:
Building the Machine:
The components used for making the Commodore 64 RetroPie Mod included an original beige Commodore 64C case, a green 3D printed conversion kit from COREi64.com, a Keyrah V2 from Individual Computers (link), a Neutrik HDMI plug (Neutrik NAHDMI-W-B), a 0.5m HDMI cable, two short USB cables (Type A/Micro B) and the power connector from a broken C64 motherboard.
Powering the RasPi
I have a few broken Commodore 64 motherboards that I use for spare parts when doing repair jobs. Early on I decided to use the power plug from one of these spare boards for powering the RasPi. This way I did not have to go get one of them ugly wall warts! A Dremel was used to separate the female power plug from the mainboard.
As the whole idea of the mod was to keep the Commodore 64 case intact, hereby retaining the option of converting the machine back to its original state, the rear side holes were used for all interface cables. Thus, the ‘Video’ port would accomodate the power inlet.
The 3D printed material is a little brittle, so care should be taken when drilling holes. Heat is another issue that should be avoided (who would have thought…). Using a rotary tool will melt the material within seconds – so be careful!
The female power plug is mounted using an original screw terminal in the case bottom. The black self-tapping screws are not included in the conversion kit from COREi64.com – I got them from China real cheap 🙂
Two pin headers were soldered into the mounting holes of the removed power switch for easy access to Ground and 5V+. Finally a modified USB cable was used to power the RasPi board through a micro USB plug. The RasPi can run power hungry devices through its USB connections of up to 2.5A, but a power supply of 1.2A will provide ample power to run the Raspberry Pi for most applications. In this context, the C64 power supply can provide 1.7A@5V. As I only intend to run a keyboard (and a green power LED) through the USB connection (and maybe a game controller) it should suffice. After about 6 hours of continuous use of the Raspberry Pi, the power supply did not even get lukewarm, so I am not too worried about overloading it 😉
The HDMI connection from the RasPi went through a Neutrik HDMI plug (Neutrik NAHDMI-W-B). Only the central part of the plug was used.
And look – it fits perfectly into the ‘Serial’ port of the original case without doing any modifications…
Finally, some hot glue was used to make sure everything would stay in place. Care was taken that no glue touched the case hereby making it easier to remove everything if I should ever want to convert the machine back to its original state.
Mounting the Raspberry Pi
Next up was mounting the bracket which holds the Raspberry Pi. The 3D printed conversion kit included some 3D printed washers to keep everything in place – nice detail!
The kit also includes black oxide screws and some stainless steel washers which makes it very easy to fasten the Raspberry Pi using the brass heat-set inserts.
The micro SD card of the RasPi can easily be reached from the outside using the small slot in the Cassette port…
In order to have the original Commodore 64 keyboard work as a modern USB PC keyboard, a Keyrah V2 was installed. The Keyrah PCB allows connection of classic computer keyboards (like the Commodore 64) to modern computers via USB. It also supports digital joysticks by translating the joystick events to key strokes.
The conversion kit came with a plate that seals off the gap surrounding the USB connection of the Keyrah.
The second USB cable was modifed with plugs that fitted the pin headers and connected the keyboard to the RasPi. No drivers need to be installed as everything is plug and play…
Power LED mod
To finish off the hardware part of the build, a green power LED was made as the cables of the original LED was too short. The LED cable was made based on this post (link)
See the finished machine and a video of the system in action on the next page…