Ingo’s Mechanical Keyboard & Kickstarter Plans
Ingo Schmied shared updates on his ZX81/TS-1000 mechanical keyboard project, featuring UV-printed keycaps that replace his water-transfer decal process. The group discussed plans to launch a Kickstarter in April, targeting around $50 CAD per set, with a goal of producing at least 20 sets in a single print run to reduce costs.
Pascal Cross-Compilers for Z80 Machines
We chatted about two Pascal options for Spectrum/ZX machines: a recently released cross-compiler targeting the ZX Spectrum Next (with CPM, ZX48, and ZXNext compilation targets), and a High Soft Pascal port for the Spectrum and 2068.
Using AI (Claude) for Vintage Computing Projects
David Anderson shared several ways he’s been using Claude as a development assistant. He used it to convert a QuickBASIC game called Skirmish to Sinclair BASIC, working around challenges like fixed-length character arrays in Spectrum BASIC (“Procrustean” arrays).
TS-Pico Development & Debugging
A significant portion of the meeting covered ongoing TS-Pico testing. David described a file-loading bug that appeared inconsistently across different TS-2068 units — present on some machines but not others. He walked through a multi-hour debugging session using Claude to add debug logging and identify the root cause. The session produced updated firmware, an API document for third-party developers, and a diff report between firmware versions.
Gustavo Pane raised the possibility of repurposing a TS-Pico board as a lightweight bus debugger using just 11 lines — data, read/write, and I/O port — without needing the full address bus.
32K RAM Expansion on the ZX81/TS-1000
Rich Jelen asked about enabling 32K on a stock TS-1000, prompting a detailed walkthrough of the MemoTech RAM module documentation and the required POKE to set RAM top (POKE 16389, 128). The conversation expanded into the ZX81/1000 memory map, the role of the ULA in the video refresh cycle, the M1-NOT signal, and the complexities of bank switching on Carl Miles’ TS-1068 prototype — which uses a 512K chip providing eight 64K memory spaces, with future plans for software-selectable bank switching via a shift register.
Composite Video Output Tips
Rich also shared a hardware tip for improving composite video on machines using the ULA 2C184: replacing the 555-timer-based modules (which have timing issues) with a simple CMOS Schmitt trigger and a transistor. This combination produces a clean, correctly-timed back porch signal — plug-and-play, no adjustments needed — and has been validated across seven or eight builds.