TS1000 / ZX81 / TS1500
TS1000, ZX81, and TS1500 — the 1K/16K Sinclair machines and Timex equivalents.
259 threads · 1524 messages · 2002-10-27 → 2026-06-29
TS1000 / ZX81 / TS1500 discussion on the list spans both archive eras and splits into three durable streams: hardware repair and modification, software preservation, and clone / international-variant cataloging. On the repair side, the group has converged on a working playbook for the most common dead-1000 symptoms — start with the ULA (V Retro Design's VLA81 replacement from vretrodesign.com is the go-to source, #6651, #6659), check the RF modulator path (NTSC VHF channel 2/3 vs. the UK ASTEC UHF unit), and only then suspect the ROM or 4116 DRAMs. Carl Miles' recapping survey on a TS1500 found only one really bad cap (C20 on the cost-reduced 2-chip-RAM design, #8979), while Patrick Leclerc and Claudius walked Carlos Nunez through the canonical "is my screen black / static / K-cursor?" diagnostic flow (#6651). For keyboards, RWAP and ZX Renew membranes are the standard answer, with tactile-keyboard kits as the upgrade (#1956). Carl's TS1000-to-TS1500 conversion project drops original TS1500 ROM chips into a TS1000 PCB so the TS1510 cartridge adapter auto-runs (#5664), but he warns the result still uses the TS1000 ULA rather than the TS1500 SCLD, so a 16K RAM pack still disables internal RAM the TS1000 way. International variants get equally careful treatment: Carl's teardown of an Argentine Czerweny CZ2000 and CZ1500 (#6736, #6737) documents that the CZ2000 uses a ZX Spectrum Issue 6A PCB with a 6C001E-7 PAL ULA but a US-style VHF modulator for PAL-Nc (3.582056 MHz subcarrier), and Joao Diogo Ramos' canonical correction is that there is no "TC1500" — all TS1500s were assembled in Portugal, while Sinclair-branded machines came out of Dundee, Scotland (#6159, #6751).
Tape preservation for the 1K/16K machines is its own technical sub-discipline because .tap/.tzx workflows that work for the 2068 don't directly work for the TS1000. The community settled on a stack: record the cassette as WAV, feed it through EightyOne (which can export .tzx) or the ZX81 Tape Converter Java tool from zx81stuff.org.uk, and fall back to Martin Vindahl's zx81-dat-tape-reader Node.js tool — which detects the 3.2 kHz frequency rather than amplitude — for marginal tapes (#2784, #6790). Adam Trionfo's archiving of Dan Tandberg's Calliope Software library (Starblasters, Metagraphics, Mazeball) became the proving ground: Starblasters was the first game Adam ever typed in on a real Timex 1000 using Ryan Gray's loaned keyboard overlay (#3061), and Ryan posted an updated .p file with the line-830 correction. Ryan also ported p2txt and hex2rem to Turbo C++ 3.0 so they'd work with modern Unix-line-ending source (#3265), and Dan Tandberg himself wrote in to bless the preservation work and donate a fresh box of tapes (#3549). The open question — which emulators actually consume .tzx for the ZX81 — surfaced again as recently as #4182: ZEsarUX doesn't, but EightyOne does. The Yahoo-era flipside was a 2009 cease-and-desist from Al Hartman of Zebra Systems against zxbruno's Zebra Graphics Designer tape preservation (#1002351), context that explains why modern-era preservation work is careful to seek author blessing first.
BASIC compatibility with the 2068 is asked about every couple of years and Ryan Gray's reply at #2711 is the definitive group answer: TS1000 BASIC is essentially a subset of TS2068 BASIC with three real token-level differences — the "quote image" character vs. doubled quotes, ** (up-arrow / symbol-shift H) vs. ^ for power, and inverse-letters-as-caps replaced by the INVERSE 1 attribute on the 2068. Tim Swenson adds that most TS1000 BASIC programs run unchanged on the 2068 and that even a fair amount of TS1000 assembly does too — RST $10 to print a character is the same on both (#2708, #4877). On the video-quality side, Paul Farrow's Chroma81 / Chroma80 SCART interfaces (fruitcake.plus.com) give ZX80 / ZX81 / TS1000 / TS1500 owners a path to RGB color, and Carl built a Wilco2009 ZX80 clone using one, debugging it down to 74LS93 substitution and pixel-clock potentiometer tweaks (#6152, #6276). The original Sinclair / Timex US-market story gets settled in the Yahoo-era thread #1001208: the original ZX81 did sell in the US briefly before the TS1000, English Micro Connection advertised actual ZX Spectrums on the East Coast in 1982-3, and a $0.30 transistor-and-resistor circuit was enough to feed NTSC machines into modern displays.
A few threads DRIFT into TS1000 territory rather than originating there. #1793 (Zebra Graphics Designer preservation) is mostly a 2068-era preservation/copyright fight but drifts into a TS1500 hardware variant subthread (#1002408). #1298 (David's archive.org book uploads) repeatedly drifts into ZX81/TS1000 books and the Ottawa-Hull TSUG newsletter. #151 (TS Pico SD card issues) drifts into Tim Swenson's Hot-Z / Hi-Z debugger work on the TS1000 with Carl troubleshooting breakpoint behavior (#8852, #8857). #355 is a typeface thread that drifts into Ryan's ZX81 motherboard provenance discussion — Issue 1 vs. Issue 3 hand-drawn traces, NTSC modulator placement, and the Dundee / England / UK molding labels (#7907). Recurring people across the topic: Carl Miles (clones, conversions, recapping), Ryan Gray (BASIC compatibility, tape tools, ZX81 motherboard history), Adam Trionfo (Calliope/Tandberg archiving, type-ins), Patrick Leclerc and Claudius (TS1000 repair advice), Joao Diogo Ramos (Portugal/Scotland manufacturing history), Paul Farrow (Chroma SCART interfaces), Tim Swenson (Hi-Z debugger, BASIC compatibility doc), zxbruno and Al Hartman (Yahoo-era preservation / copyright tension).
Key threads
- Slightly off topic… TS1000 Help (#6651 on groups.io) — Canonical dead-TS1000 troubleshooting thread — symptoms, RF-vs-composite advice, and V Retro Design's VLA81 ULA replacement as the standard known-good repair part.
- TS1000 -> TS1500 Conversion Project (#5664 on groups.io) — Carl Miles' worked conversion of TS1000 PCBs with original TS1500 ROM chips for TS1510 cartridge auto-run, with the ULA-vs-SCLD caveat spelled out.
- Picked these up recently from Argentina... (#6736 on groups.io) — Carl's deep teardown of the Czerweny CZ2000 (Spectrum Issue 6A PCB, PAL-Nc subcarrier) and CZ1500, with JDR's TC1500 / Portugal-vs-Scotland manufacturing correction at #6751.
- zx81 tape recovery (#2784 on groups.io) — Anchors the modern TS1000 tape-archiving workflow around Martin Vindahl's 3.2 kHz-frequency-detection Node.js tool — the fallback when EightyOne can't decode a marginal cassette.
- Archived "Starblasters" by Dan Tandberg (#3061 on groups.io) — Adam Trionfo's first real-hardware TS1000 type-in (from a 1983 Sync) with Ryan Gray's corrected .p file, and ultimately a letter from Dan Tandberg himself blessing the preservation work (#3549).
- Archiving "Metagraphics" by Calliope Software (#3128 on groups.io) — Documents the full WAV → ZX81 Tape Converter / tzxtools / p2txt / hex2rem pipeline including Ryan's Turbo C++ 3.0 port, plus the unresolved question of which emulators load .tzx for the ZX81 (#4182).
- T/S 1000 and T/S 2068 - How Compatible? (#2707 on groups.io) — Ryan Gray's #2711 reply is the definitive groups.io-era answer on TS1000 vs TS2068 BASIC token differences — quote image, ** vs ^, INVERSE attribute — and surfaced an unscanned Wiley quick-reference card.
- Sinclair ZX80 and the Chroma80 (#6152 on groups.io) — Paul Farrow's Chroma80/Chroma81/Spectra SCART interfaces give the 1K/16K machines real RGB output, and Carl's Wilco2009 ZX80 clone build doubles as a parts-substitution diary (74LS93, pixel-clock pots).
- Other Sinclairs (archive.org) — Yahoo-era (2007) foundational Q&A — NTSC/PAL jumper on the TS1000 motherboard, what Sinclair models actually shipped in the US, English Micro Connection's east-coast Spectrum ads, and Glen Goodwin's $0.30 transistor NTSC circuit.
- Some news. Also looking for Zebra Systems Graphics designer (archive.org) — Yahoo-era (2009) flashpoint where Al Hartman pushed back on zxbruno's preservation of Zebra Graphics Designer tapes — the copyright tension that modern preservation work has carefully avoided by seeking author blessing first.
- TS1000 keyboard repair options? (#1956 on groups.io) — Membrane-replacement sources (RWAP, ZX Renew) plus tactile-keyboard alternatives — the standard answer when a TS1000 mylar delaminates at the motherboard connector.
All threads (259)
↳ marks a thread where this topic begins mid-conversation — the link jumps to the message where it starts.