Now you can check all of the ICs, ROMs and I/O ports (I/O port checks requires a Full Test Harness) on your C64.

The 586220 Diagnostic Cartridge was used by Commodore themselves to test every unit as it came off the assembly line.

Thanks to various contributors over the years, the 586220 has been updated to the 586220++ and provides proper Kernal detection and SX-64 support.

Pair this with our Full Test Harness and you will be well on your way to identifying any issues you might be having with your C64.

We also offer a C128 Diag and a Diag 264 cartridge for the Commodore 128 family and the Commodore C16/+4 family respectively.

Full manual and support can be found on our Support Wiki.