TSU Meeting SUNDAY — July 20, 2025
David, Paul, Mowgli, John Mark Mobley, Phil, Joe, Ryan, Adam, Christian, Brian, Gustavo, Arnulfo Ordaz, Stuart, Greg, Johnny
The meeting opened with news that the third ZX Spectrum Next Kickstarter had launched the previous day, billed as the last run; Phil reported he had backed it, primarily for the on-board Sinclair QL emulation (multiple QL OS images, SD-card storage, and "plus-three" disk capability of some form). That led into a long discussion of QL floppy formats (essentially Atari ST / IBM-compatible), Shugart-compatible drives, hard- vs. soft-sectored discs, and the Greasaweasel flux imager as a way to archive Oliger, Larken and similar floppies — Mowgli described his Python workflow for decoding Oliger and Larken directories out of the IBM-format dumps the Greasaweasel produces.
The TS-Pico update was the main project report. Ricardo has the Pico-side firmware essentially ready, including an in-place flash-ROM updater that rewrites the Timex ROM without pulling the chip; Gustavo is finishing a ROM bug uncovered in the past few weeks so a single combined update can ship. Tim's new Pico-based board that emulates the ZX Printer / TS2040 (watching the printer data lines, reassembling the bitmap, OCR-ing the text, and serving the result over Wi-Fi to a browser) was demoed and is ready for release, but exposed an LPRINT bug introduced by Gustavo's ROM changes: only the first line/token prints, then garbage, while LLIST is fine. Brian reproduced it without Tim's board on a real 2040, isolating it to the Pico ROM clearing the print buffer too early; reproduction steps are being sent to Ricardo and Gustavo.
Christian showed his "Spectrenstein Mark I" — a DK-Tronics ZX81 keyboard repainted and wired to a ZX/Pico Spectrum board — and walked the group through which keys were dead: S, B, N, M, symbol-shift, space, delete and period. With the Spectrum keyboard matrix on screen (Joe posted the diagrams), the group diagnosed it as a half-row break on the line carrying B–space (address A15 side), plus a separate bad connection at the S key switch; the recommended next step is to buy a cheap multimeter (Harbor Freight, Amazon) and ring out the ribbon and solder joints, possibly adding a bodge wire. Power-supply safety for original 2068s was also covered — the linear bricks are now ~50 years old, rectifier diodes and caps can fail and pump AC or unregulated voltage into the on-board regulators, so members are switching to small 15 V switching supplies; tantalum vs. RIFA capacitor failure modes got a colorful aside.
David then surveyed who used a modem with their Timex (2050, ByteBack, AERCO, external Hayes/USR via a full DB-25 RS-232 for all the handshake/ring-indicator lines) and previewed his own project: a Raspberry Pi Pico W board that emulates the TS2050 over Wi-Fi with Hayes-style AT commands, board designed and most of the firmware written, target demo at VCF Midwest in September — including a test against Fred Nachbaur's ZXTerm80 on the TS1000. VCF Midwest logistics were discussed (parking is tight this year; a Meridian-based on-site phone network with up to four lines per table will let exhibitors run BBSes, POTS, even ISDN between tables). The group welcomed a new attendee, Arnulfo Ordaz, a physics trainer from Mexico City who used a 2068 (acquired grey-market in Mexico in the 1980s) to write Z80 physics simulations for his students; Gustavo offered to be his Spanish-language contact. Stuart (Zebra Systems) checked in about his remaining ZX81 kit inventory — including ~30 assembled (not kit) units he'd like to pair with a non-invasive UHF channel-33 RF-to-HDMI adapter if anyone knows an RF engineer. Finally, the August third-Sunday meeting was moved to August 10th (David is away on the 17th), with the Monday meeting following on August 4th and Labor Day for September TBD.
Highlights
- ZX Spectrum Next third (and reportedly final) Kickstarter launched July 19; Phil backed it for QL emulation
- TS-Pico update nearly ready: Ricardo's firmware can re-flash the ROM in place; Gustavo finishing a ROM bug before release
- Tim's Pico-based ZX Printer / TS2040 emulator demoed — reassembles the bitmap, OCRs it, serves over Wi-Fi; LPRINT bug traced to ROM clearing the print buffer too early
- Christian's "Spectrenstein Mark I" DK-Tronics keyboard diagnosed live as a half-row break (B/N/M/sym-shift/space) plus a separate bad S key
- David previewed a Pi Pico W Wi-Fi modem that emulates the TS2050 with Hayes AT commands, targeting a VCF Midwest demo in September
Projects discussed: TS-Pico Topics: Pico / modern interfaces (UnoDos, etc.) · Printers & plotters · Modems, serial & RS-232 · Repair & restoration · User group meetings & events · Disk & floppy systems (Larken, AERCO, Oliger)
Summary generated from the meeting recording; the full transcript is kept in the group's private archive.