Tuesday 3 May 2016

VIC20 Diagnostics Cartridge and Test Harness Kits

This is an old post, preserved for reference.
The products and services mentioned within are no longer available.

The first batch of VIC20 diagnostics cartridge kits sold out faster than I was expecting, and it's taken ages to get a new batch of PCBs after being messed around by the PCB house. I have now had the PCBs made elsewhere, so they are now back in stock.
The boards are now a fetching shade of blue, to match the edge connectors. The loopback plugs fit into the various connectors around the VIC20 and allow testing of all the ports.
The keyboard connector can be omitted if you don't want to open the case.
The software then runs through a series of tests, identifying any faults with your VIC20.
The test keeps looping around, so you can use this for burn in testing.
I've written a user guide for the VIC20 Diagnostics cartridge to try to explain what all of these tests indicate

The kit will be available in two versions, the same loopback plugs with a choice of cartridges.

Dedicated diagnostics cartridge kit

This version comes with a dedicated diagnostics cartridge, with the VIC20 diagnostics ROM and the RAM it requires to run.
This is designed to be used as a bare board plugged into the cartridge slot, or can also be fitted into a standard cartridge shell.

ROM/RAM Cartridge with diagnostics loopback kit

The other version comes with the DIP switch controlled ROM/RAM cartridge. Using the DIP switches, a series of ROM cartridges can be selected, includes the diagnostics ROM and a few games cartridges to test the system. It can also be used as a 27K or 32K RAM cartridge.
You can also replace the ROM chip and add your own selection of up to eight 4K or 8K ROM images.
The DIP switch controlled cartridge is used here as the menu driven Penultimate Cartridge does not include the diagnostics ROM (you can't navigate the menu if your VIC20 is not working or if you have the keyboard loopback installed).

VIC20 diagnostics kit with ROM/RAM cart
Both versions are available from my Tindie store, either as PCBs, kits of parts, or assembled and tested sets.

2022 Update: The Penultimate Cartridge includes a Dead Test that can run from the menu or by holding down reset. This is now available from  The Future Was 8 bit