Timex Sinclair User Group Meeting — September 5, 2022
David Anderson, Tim Swenson, Andy Hradesky, Joe, Carl Miles, Jamie, Adam Trionfo, Ryan Gray, Evie, Tim Horner, Jeff, Andrew, Willie
Two new faces joined the meeting: Andy Hradesky — formerly of the San Francisco group, the last editor of its Timelines newsletter, and famous on the list for once selling QLs door-to-door through the Air Force — and Joe, who told the story of trying to mount a 64K ZX81 (with a Memotech RAM pack) inside a salvaged Hazeltine 1500 terminal, rebuilding the Stackpole keyboard from TI-99/4A donor switches before frying the RAM card on a power-supply capacitor. Andy is rebuilding his QL setup: he's tracked down both a North American and a European QL (the latter with a Trump Card and Sinclair 3.5" floppies), plus Minerva ROMs, a 640K expansion board, and a 386SX with a QXL card so he can network three QLs again. The group discussed QL emulators (QemuLator, SMSQ/E emulator, sQLux) and SMSQ/E on a Gold Card.
The technical centerpiece was Evie's Backbit cartridge, which now boots and runs TS2068 DCK (dock) files — she demoed Crazy Bugs and Q-Bert. The key to TS2068 support, versus the simpler Spectrum bus, was honoring the ROSCS (ROM chip-select) signal, plus an 8-byte handshake that tells the 2068 to bank-switch to the cartridge and jump to its code. Q-Bert needed a workaround (jumping to the top of memory instead of resetting). Discussion turned to using the BANK ENABLE pin to substitute a Spectrum ROM and turn the 2068 into a Spectrum emulator — Evie plans to offer BIOS-ROM selection from the Backbit menu and will re-add the Kempston joystick port she had dropped from the 2068 adapter. The new boards ship in a couple of weeks; she has roughly 10 cartridges left before her next STM chip order arrives. Brazilian developer Ariel Ranieri's multi-game TS2068 cartridges (menu-selectable via dip switches or a boot menu) also came up.
Tim Horner showed his printer work: an Arduino ZX81-bus shield that drives both a ZX Printer and a TS2040 directly, bypassing the host machine. He's printed replacement ZX Printer belts on his 3D printer (about five cents of rubbery filament), found locally-stocked thermal paper at roughly the right width, and is now building a Windows-to-printer bridge — a Python program that emulates an Epson ESC/P 9-pin impact printer on a serial port so any Windows app can print to a vintage Sinclair printer. The 2040 turned out harder to drive than the ZX Printer despite its simpler thermal head, because each write requires a paired read in the right sequence. This connects to Stewart Neufeld's longstanding Sinclair World bounty for getting his stash of TS2040/Alphacom 32 printers running off modern hosts.
Other threads: Carl shared his recipe for repainting silver TS2068 / 2040 cases (Krylon Short Cuts silver from Michaels, with a clear top coat and a separate grey-green for the two-tone bottom). Tim Horner demoed Hoglet/IanS's Raspberry Pi + CPLD RGB-to-HDMI converter — he's built it into a case with the analog daughterboard and uses it on his Amstrad CPC and ZX81; profiles cover many machines but he hasn't nailed the TS2068 sync timing yet. Carl described an alternative TMS9928-based YUV-to-RGB internal mod for the 2068 that would preserve the BRIGHT bit. Tim also showed his USB-keyboard-to-Sinclair adapter now working on the 2068 after swapping CMOS drivers for TTL to match the SCLD's levels. New member Jeff is teaching himself AROS cartridges by trying to put a Wordle-style BASIC game into one — the group walked through the fact that the Technical Manual documents the AROS/LROS headers but provides no worked BASIC example. David walked Tim through configuring Fuse for the TS2068 (set both the machine and both ROMs — HOME and EXROS) and shared a ~6-line BASIC program that exposes an apparent bug in the 2068's DRAW arc routine, producing geometric artifacts instead of curves for certain parameter values. Next meetings: Sunday September 18 at 2 PM, then Monday October 3.
Highlights
- Andy Hradesky rejoins the community — former editor of San Francisco's Timelines newsletter and one-time door-to-door QL salesman — and is rebuilding a three-QL network.
- Evie demoed Backbit running TS2068 DCK files (Crazy Bugs, Q-Bert), using the ROSCS signal plus an 8-byte cartridge-handshake; Spectrum-ROM substitution via BANK ENABLE is on the roadmap.
- Tim Horner has both a ZX Printer and TS2040 printing from an Arduino, with a Python ESC/P emulator in progress to let any Windows app print to them.
- Tim Horner is running a Raspberry Pi + CPLD RGB-to-HDMI converter (Hoglet/IanS design) across several retro systems; TS2068 sync timing still needs work.
- Walkthrough of configuring Fuse for the TS2068 (machine + both HOME and EXROS ROMs) and a tiny BASIC program that shows the 2068's DRAW-arc routine producing artifacts for certain parameters.
Topics: Cartridges, EPROM & dumping · Pico / modern interfaces (UnoDos, etc.) · Printers & plotters · Video upgrades (composite, RGB, HDMI) · TS2068 / TC2068 · Spectrum emulation & software
Summary generated from the meeting recording; the full transcript is kept in the group's private archive.