TSU Meeting MONDAY — August 5, 2024

David Anderson, Carl Miles, Ryan Gray, Joe, Gustavo, Adam Trionfo, Jack, Tim Swenson, Johnny Red

Most of the meeting was a deep dive into the TS1510 cartridge clone and the work around running real software from it. Carl walked through the differences between the Superflow and Claudius cartridge designs, the A14/A15 decoding bug that prevented Flight Simulator (the only stock 16K Timex cartridge) from working, and his bodge fix using two diodes and a pull-up to OR the upper and lower 8K chip-selects together. Joe is iterating an EDA version of the same board; Carl will send him a sketch of the diode-AND. The group also confirmed that adding RAM beyond the built-in 16K conflicts with the cartridge address map, except for the Wilf Rigter 32K design, which Carl has verified works.

Ryan presented his ROMifier for turning .P tape images into cartridge ROM images. His first version emulated the hand-rolled init/copy loaders Timex used on the four original cartridges (Chess, States & Capitals, Backgammon, Flight Simulator) and split programs across the 8K boundary as needed. After hitting programs the original style couldn't handle (ViewCalc/ViewFile's load-verification trick, several Bobstuff games), he rewrote it as a tape-style loader that drops the P-file's system variables and program/display/variables blocks into ROM almost verbatim — and that now works on essentially everything except Quicksilver games, which need their own add-on hardware. A nice side-effect: programs converted with the tape-style loader start instantly on a TS1500 (no five-second RAM-zeroing pause), prompting discussion of stripping the memory-zero step from the older converted ROMs and adding an optional TS1500-ROM swap to the interface board. Adam, Carl and Ryan met in person on Saturday and played Impact, Crossy Road, Crazy Kong and Frogger on real hardware via the 1510 clone; an Atari-style joystick port (mapped to the cursor keys) is now planned for the next interface PCB revision.

Carl then gave a status update on his TS2000 prototype recreation, based on a Czerweny (Cerenzi) CZ2000 case from Argentina with a Spectrum board, an NTSC ULA, swapped crystals (3.58 MHz colorburst + 14.111 MHz main) and the VHF modulator the Argentine cases already accommodate. Most of the discussion was a long, good-natured argument about the prototype's case colour in the one surviving CES press photo — silver vs. black vs. "space grey" — with Gustavo and Johnny Red's Argentine references and Ryan's lighting/backscatter analysis weighing in. Carl is sticking with silver, using domed rainbow stickers in place of the inlaid colour dots, masking the red "TIMEX 2000" lettering, and noting the Czerweny shielding paint (which complicates the old "FCC delays killed the 2000" story attributed to Danny Ross). David also clarified that the "2000-series" model numbers (2048/2072/2068) were largely marketing — Danny Ross coined "2068" at announcement.

Wrap-up items: Jack confirmed he shipped David two fire-damaged FDD3000s and a melted box of 3-inch disks (carrying on the Bill Miller-style preservation ethic of saving even the wrecked hardware); Tim Swenson reported back from a local computer festival where he met two nearby Sinclair owners (one with a QL + vDrive); and Ryan walked the group through photo tours of The National Museum of Computing at Bletchley Park and the Centre for Computing History in Cambridge, including the John Grant Spectrum prototype (with disk-drive support in its later ROM) and a wide cross-section of Sinclair, Acorn, Amstrad, Apple, SGI and other machines. Next meeting: Sunday Aug 18, 2 pm Eastern.

Highlights

Carl's TS1510 clone: diode-OR bodge fixes Flight Simulator's 16K paging; Joe iterating his EDA version next
Ryan's ROMifier rewritten as a tape-style loader — now handles ViewCalc, Bobstuff games, everything except Quicksilver
Side-effect discovery: tape-style loader makes cartridges start instantly on TS1500 (no RAM-zero pause)
Joystick port (mapped to cursor keys) and optional TS1500-ROM swap planned for next interface PCB
Carl's TS2000 prototype recreation in a Czerweny CZ2000 case with NTSC ULA + swapped crystals is underway

Projects discussed: TS1510 Cartridge Interface Clone Topics: TS1510 cartridge interface · Cartridges, EPROM & dumping · Prototypes & rarities · Hardware projects & new boards · Machine code, Z80 & assemblers · Other retro computers

Summary generated from the meeting recording; the full transcript is kept in the group's private archive.