The company Kolf Computer Supplies (KCS) in the Netherlands made a series of cartridges for the Commodore C64 computer.

Examples are: Tape Queen, Tape Speedsaver, Speedmon, Tape Speedsaver Combi, Disk Speedloader and the Disk Speedloader Combi.

All the cartridges use the same hardware which is basically a PCB with an 4 kB or 8 kB EPROM, an On/Off switch (with LED) and a Reset switch. You can view the schematic and PCB-layout of the cartridges below.

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To make a replica PCB, you need to know where all the copper-traces connect to. For the bottom side, this is not so difficult, you only need to remember to draw the mirror image in a PCB drawing program. I measured all the locations of the holes and via's and drew them in the PCB drawing program. After that, I connected all the copper-traces to the holes and via's.

The upper-side of the PCB is more difficult, because the components are obscuring the copper-traces. You can use a multi-meter and measure all the connections, but that is not that easy and can lead to mistakes if the components themselves connect different holes internally. For that reason, I removed all the components from the upper-side of the PCB.

The replica PCB is very close to the original, but there are some small differences. The PCB drawings are made with EasyEDA, which is a free online PCB development program.
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After drawing the replica PCB, I also have drawn the schematic. The schematic is also drawn with EasyEDA.
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Building your own KCS cartridge replica is possible with the information above. I did spend hours and hours making and checking the PCB and schematic, but I can't guarantee that the drawings are perfect. If you build a KCS cartridge replica with this information, it is on your own risk. You also must consider that the company KCS is still active, and has all the rights to the design of the KCS cartridge.

But if you are successful, let me know!

The technical files for the KCS cartridge.
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