Usagi Electric’s latest TM990 video is a satisfying reminder that a vintage computer is most interesting when it does something. After replacing a failed RAM chip, the creator gets the Texas Instruments system talking to a Hazeltine 1500 terminal, works through further troubleshooting, and finally runs a one-dimensional Life program on a printer.
From repair to a running program
The 24-minute video, published on 27 September 2026, starts with the replacement RAM. The creator then uses BASIC to dump the machine’s ROM contents. That program only just fits in the original memory: BASIC reports 14 bytes free. An added RAM expansion board lets BASIC report 7,852 bytes free, although the creator says it is not yet clear whether the system is using the board’s full capacity.
The payoff is a one-dimensional Life program printing its evolving pattern. The creator adapts a version previously run on a Data General machine, changing BASIC syntax and improvising a source of pseudo-random values because TM990 BASIC lacks a random-number operator. The printed result is a more memorable proof of life than a boot prompt alone.
Still more to explore
The video does not settle every hardware question. A second ROM board remains to be investigated, and an eight-inch floppy drive is a future project, not something demonstrated here. For now, it is a compact story of fault-finding, memory limits and getting an old system back to useful work.
Watch the original: “The TM990 Plays 1D Life!” — Usagi Electric, 27 September 2026. Evilpigeon.dk has not tested this hardware itself.
