piątek , 23 luty 2024

Installation of additional Expansion Port inside of Commodore 64

In vacation of 2006 I began with the second approach of soldering additional Expansion Port to my Commodore 64. The first attempt, which took place somewhat earlier, ended in failure: the C64 didn’t started at all and I’ve got damaged my first cartridge named Super Mian Box III. As it turned out, it was my mistake in the soldering. Jak się później okazało, był to mój błąd w lutowaniu. Prototype of this extension was made on 6.03.2005.

The second approach, however, was a success, which resulted in the inclusion of the Action Replay v7.3 inside of my C64. Original Expansion Port remained functional, and what’s more – the two ports, through my efforts are switcheable! I’ve added the switch, by which I can switch between the two ports. When the original Expansion Port has no module connected, it reports to naturally blue screen of C64. Switching is possible if you simply switch 3 signals from the port: +5V (pins 2 and 3), GAME (pin 8) and EXROM (pin 9).

For the whole action of soldering that second port would ever be possible, first I cut the Expansion Port of the another damaged C64. The first approach was carried out by soldering the two ports by using the wires from the hard disk. I do not recommend this technique because of its high fusibility isolation and poor quality of wires. Soon I bought a solid wires (unfortunately, only 12-wire) and set to work. Soldering required a large dose of patience, because I had to make a total of 80 connections of the wires. I moved the Reset and Freeze buttons upon the F1 key of the C64 case. Finally the work ended with a success and since that time I’m working with the cartridge, which is inside of my C64, with the possibility of connecting another module to the original Expansion Port.

In the meantime, I got to the connection of two additional Joystick ports, which commonly operate under the name of „4-player Adapter. I’ve also did some diagnosis of broken 1541 II drives. Commodore 64 was subsequently tested in the open air. Later I’ve unsoldered this addition, because it got refused to work properly.

Also I will tell about the fact that the project was inspired by the available long overdue extensions to C64, for example those ones, which gives you the possibility of connection total amount of 3 cartridges standing vertically, but some of them unfortunately doesn’t work with the selected modules, such as Action Replay. Additional inspiration for the creation of this project was a Rabbi’s C64 which I saw in action at North Party 9. Indeed, Rabbi installed Action Replay inside of his C64, but he did it on a permanent basis.

Plenty of cables: additional Expansion Port and +60k linked on universal plate.
Testing on C64 after modifications on fresh air.
Village mood!
Self-made 4-player adapter.


Special thanx to FMan which two photos of Expander gave me possibility to understand rule of switching signals in Expansion Ports.

Szczecin, 20 February 2009