TSU Meeting SUNDAY — July 16, 2023
David Anderson, Adam Trionfo, Jeff Burrell, Jeff Coleman, Ryan Gray, Mike, Ingo, Gustavo, Mark, Rui, David Solly, John Brown
David opened with an oddball history piece: the InnoVision Presto Digitizer (advertised for the ZX80 in Syntax Z80 by David Thornburg, never shipped) and how Thornburg later founded Koala Technologies — connecting the Koala Pad and the Zebra TechDraw/Painter line back to the Sinclair world. From there he moved into a long working session on his ongoing tape-archiving effort: he's been pulling apart user-group library tapes (Capital Area, Long Island/LIST Lib 2.2 2068, and others), running them through tzxtools (tzx-wav) and the Fuse audio-to-tape utility, and falling back to Fuse itself to recover blocks the command-line tools miss. He walked through the painful manual case — opening a WAV in Fuse, browsing the per-program blocks, saving each one out individually, then using the Fort Worth header-reader program to recover load addresses. A tip from the Bally/Astrocade archiving world to try Audacity low-pass filtering on noisy tapes was picked up for future use.
Jeff Burrell demoed the latest revision of his open-hardware video board for the TS2068 — a Timex-bus snooper that mirrors video memory and the video-control ports into onboard RAM and regenerates the signal as VGA, with 80-column text and extra 16-color 128×192 / 4-color 256×192 Timex graphics modes. David and Ryan are the two beta testers. Side-by-side captures showed the board producing a clean image on David's main 2068 while the same machine's composite output is badly degraded; a second mystery 2068 (originally Eric Johnson's, with a ceramic Aug-1983 ROM, a Hitachi X-ROM, and unusual board features) wouldn't display through the board at all. Jeff confirmed all his boards are open hardware and that a small run of video boards may be made available once the bugs are out. The conversation rolled into Gustavo's reminder that the published TS2068 schematic has a wrong resistor value (and Sam's Computer Facts is closer but not perfect), and a warning not to gut the RF modulator since some of those parts are needed for composite generation.
Ingo showed the next iteration of his enlarged TS1000 build: 3D-printed black PETG case (with a clear-PETG experiment), barrel-jack power input, real power switch, removed RF modulator, composite-mod board grounded to the modulator can, right-angle keyboard header, and a planned power LED. He plans to release the 3D models and design files — and got the (semi-serious) suggestion to use an RGB LED driven by a 2068 output port. Mike walked through his prototype RS-232 serial board for the 2068 (Motorola 6850, decoded at ports 126/127), griped about the data-line scrambling on the TS2068 expansion connector, and discussed whether to respin it with an address decoder; David pointed at the two existing Timex-modem terminal programs as candidates for patching to talk to it. Mike's 2040 printer is dead (no 28V from the supply); the group has been using Bob Orfeld's 1980s schematic, which is known to have errors. Stuart reportedly still has new-old-stock 2040s.
Short items: David Solly's Larken Spectrum-emulator daughterboard needs the modification wire re-soldered and a manual that is unclear. Jeff Coleman recapped VCF Dallas — small Sinclair presence (Spectrums including a 128, brought by a member to introduce them to US visitors), and a standout Apollo Guidance Computer reverse-engineering talk (Curious Mark on YouTube). Jeff also has a manual for RPNZL, a Forth for the ZX81, but no software yet. David has recovered the long-thought-lost AMscript word-processor manual (came in a box from Paul) and will archive it; he was testing 68-column AMscript through Jeff's video board. Rui (Portugal) showed his black TC2068 / TC2048; Mark (Netherlands) showed several European variants including a Chilean NTSC 2048. A new attendee, John Brown (Albuquerque), introduced himself: ZX80 kit-built, later ran two TS2068s in the UNM emergency room in the mid-80s as a patient triage/tracking system written largely by Dr. Dan Tanberg, and built a Winchester hard-drive interface for the Sinclair. David plans to get John and Carl Miles on a future call together, and to invite Dan Tanberg to talk about the ER system. Next meeting: Monday, August 7 2023, 9pm Eastern.
Highlights
- David walked through his tape-archiving workflow: tzxtools (tzx-wav), Fuse audio-to-tape, manual per-program extraction in Fuse, and the Fort Worth header-reader trick for load addresses.
- Jeff Burrell demoed a smaller revision of his open-hardware TS2068 VGA video board (80-col text + extra Timex graphics modes); David and Ryan are beta-testing, a small run may follow.
- Ingo showed the next iteration of his enlarged TS1000 — 3D-printed PETG case, real power switch, gutted RF can, composite mod, planned release of design files.
- The long-lost AMscript word-processor manual has surfaced and will be archived; David tested 68-column AMscript through Jeff's video board.
- New attendee John Brown described running two TS2068s as an ER patient-triage system at UNM in the mid-80s (software by Dan Tanberg) and building a Winchester hard-drive interface for the Sinclair.
Projects discussed: Library Tape Archiving Process Topics: Tape & library archiving (TAP/TZX) · Tape, cassette & loading · Video upgrades (composite, RGB, HDMI) · Hardware projects & new boards · Modems, serial & RS-232 · TS2068 / TC2068
Summary generated from the meeting recording; the full transcript is kept in the group's private archive.