This is a diagnostic harness and the description of the diagnostic cartridge for the Commodore VIC-20, based on the original Commodore diagnostic harness and software.
The Diagnostic Cartridge is based on the design for the VIC-20 Super Expander II design.
Alternatively, the Hyper Expander Cartridge can be used as a Diagnostic cartridge, too. All RAM (except the BLK5 8K block) can be installed for the Diagnostic.
The general description of the VIC-20 Diagnostics can be found in the "Top-Level Project" folder.
The Rev. 1 of the User Port PCB just has a reduced part count.and a new logo.
Please find the (C64) cassette port adapter here.
Please also refer to my website