What is the KCS Power Cartridge?

The KCS Power Cartridge is an iconic utility cartridge for the Commodore 64 and C128, developed by Dutch company Kolff Computer Supplies. It combines a fast-loader, machine code monitor, freeze function, BASIC toolkit, Total Backup and 16 KB of on-cartridge RAM into a distinctive bright red housing.

Who developed the KCS Power Cartridge?

Kolff Computer Supplies (K.C.S.), founded by Krijn Kolff in the Netherlands. Released around 1986, the cartridge was sold primarily in the Benelux region and became one of the most popular utility cartridges for the C64 in the Netherlands.

How much faster does the fast-loader make disk loading?

The built-in fast-loader speeds up disk and tape loading by 4 to 6 times compared to the standard C64 routines. It activates automatically when you boot the C64 with the cartridge inserted and works with all standard C64 disk drives.

How does the freeze function work?

Pressing the white button on the cartridge triggers a freeze that pauses the running program. The complete machine state including CPU registers, stack, I/O registers and RAM pages is saved to the 16 KB on-cartridge RAM buffer. You can then export this snapshot to disk or tape and resume it later.

What can the machine code monitor do?

The built-in monitor provides full access to the C64's memory and supports 6502/6510 disassembly. You can examine and modify memory with EXAM and POKE commands, view hex and ASCII output, set breakpoints, execute single steps and inspect or modify all CPU registers. A disk monitor is also included.

What is Total Backup?

Total Backup is a feature that saves and restores the complete memory contents of the C64. It is useful for developers who want to preserve their work in RAM, for creating game snapshots, or for backing up any running program state to disk or tape.

Is the KCS Power Cartridge compatible with the Commodore 128?

Yes. The KCS Power Cartridge works on both the Commodore 64 and the Commodore 128 in C64 mode via the standard expansion port. Some commercial games with copy protection may conflict with the cartridge.

Can the KCS Power Cartridge be emulated?

Yes. ROM dumps of the KCS Power Cartridge are available in .bin and .crt formats and are compatible with modern C64 hardware such as the 1541 Ultimate II+ and EverDrive cartridges. Emulation is also possible via software emulators that support cartridge ROMs.

KCS Power Cartridge

The KCS Power Cartridge for the Commodore 64

The KCS Power Cartridge by Kolff Computer Supplies is an iconic utility cartridge from the 1980s, beloved by C64 and C128 users across the Benelux region. Its distinctive bright red housing with a white button conceals an impressive set of features: a fast-loader, machine code monitor, freeze function, BASIC toolkit, Total Backup and 16 KB of on-cartridge RAM.

Designed by Krijn Kolff and released around 1986, the KCS Power Cartridge was the Dutch answer to the Final Cartridge 3. The cartridge shipped with manuals in six languages including Dutch, English, German, French, Italian and Swedish, reflecting its wide reach across the European market.

The KCS Power Cartridge in its distinctive bright red housing for the Commodore 64

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KCS Power Cartridge: Key features at a glance

The KCS Power Cartridge packs everything a C64 user needs for productive work into a single plug-in module:

▶Fast-loader: disk and tape loading 4 to 6 times faster
▶Freeze: pause any running program, save state to on-cartridge RAM
▶Total Backup: save and restore complete memory contents
▶Machine code monitor: 6502/6510 disassembler, breakpoints, single-step execution
▶BASIC toolkit: extra commands for programming and debugging
▶Pause function: suspend any program without a full freeze
▶Hardcopy: print screen contents to a Centronics printer
▶16 KB RAM: on-cartridge buffer for snapshots and backups

KCS Power Cartridge startup screen on the Commodore 64

The KCS Power Cartridge startup screen displaying the KCS logo when the C64 boots

Box, PCB and accessories

The KCS Power Cartridge came in a well-presented box complete with manual. The reverse of the box lists all features in detail. On the PCB you can see the ROM chips and the 16 KB RAM modules required for the freeze function.

Machine code monitor and BASIC toolkit

The KCS Power Cartridge machine code monitor is a full-featured tool for experienced C64 programmers. It supports the complete 6502/6510 instruction set, allows inspection and modification of memory and registers, and provides breakpoints and single-step execution for detailed debugging.

The BASIC toolkit extends the C64's standard BASIC 2.0 with useful commands for programmers and advanced users. Together with the disk monitor and hardcopy function, the KCS Power Cartridge turns the C64 into a genuine development platform. The manual covers every function in detail.

Download the manual (PDF):

KCS Power Cartridge PCB close-up showing ROM chips and 16 KB RAM modules

Emulation and modern compatibility

The KCS Power Cartridge lives on in the modern retro world. ROM dumps in .bin and .crt format are available and compatible with the 1541 Ultimate II+, uIEC and EverDrive cartridges. This means the KCS Power Cartridge functionality can be enjoyed on modern hardware.

Original second-hand cartridges are available on retro platforms and collector markets. Condition varies, but the robust design means many units still work perfectly. A contact clean with isopropyl alcohol resolves most issues on older units.

KCS Power Cartridge: Technical specifications

Hardware

Extra RAM	16 KB on-cartridge buffer
Housing	Bright red plastic
Button	White freeze/pause button on front
Expansion port	Standard C64/128 cartridge port
Manuals	Dutch, English, German, French, Italian, Swedish

Fast-loader

Speed	4 to 6 times faster than standard
Method	Efficient block transfer protocol
Disk drives	All standard C64 drives
Tape	Also accelerated
Activation	Automatic on boot

Freeze & Backup

RAM buffer	16 KB on-cartridge
Saves	CPU registers, stack, I/O, RAM pages
Export	To disk or tape
Total Backup	Full memory save and restore
Resume	Continue any frozen program

Machine Code Monitor

CPU	6502/6510 disassembler
Commands	EXAM, POKE, hex and ASCII display
Features	Breakpoints and single-step execution
Registers	Full inspection and modification
Disk monitor	Built-in disk access

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Find a KCS Power Cartridge

Original KCS Power Cartridges can be found on retro marketplaces, from collectors and occasionally on online auction platforms. Browse Amazon for C64 hardware and accessories.

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