The PC8300 was announced at the 1983 Consumer Electronics Show. Marketed, and maybe manufactured, by Unisonic, it was a “clone” of the ZX81. The ROM featured a highly similar BASIC but with the character code table moved to the custom chip. As a clone, it wasn’t particularly compatible with the ZX81: the display file appears […]
MIDI, the Musical Instrument Digital Interface, was conceived in 1981 and appeared in synthesizers and drum machines in 1983. It was a means of connecting synthesizers and other musical instruments using a vendor-agnostic connector/cable and digital information protocol. It allowed a musician to connect his Yamaha keyboard to his Roland drum machine and play them
MIDI on Timex/Sinclair Computers Read More »
Reprint of an article about a medical practice program written by a practicing ophthalmologist.
ZX81 in an Ophthalmologist’s Office Read More »
In testing my latest iteration of an RGB to SVIDEO/composite board, I managed to toast my 2068. Symptoms point to fried RAM chips, according to an article on DIY fixes to the 2068, so I’ve ordered replacements. The circuit boards above, from left to right, are a buffered 2068 expansion bus, an attempt to make
A Temporary Setback Read More »
I’ve revised my RGB->SVIDEO design to be standalone. It uses a through-hole connector with all parts on the “back” of the PCB so it can plug directly into the 2068. No improvement to video quality, though I plan to build up a circuit that uses the Pound HD Link Cable for Sega Saturn to see
A Small Update on Video Read More »
K-2 Electronics Design offered a particularly robust keyboard upgrade to the ZX-81/TS-1000, one that far exceeded the options available from many other manufacturers at the time. The Kradle was more than just a keyboard upgrade: it included an expansion card with 64K RAM, a joystick port, cassette signal conditioning, extra automatically shifted keys and several
K-2 Kradle Keyboard and Enclosure Read More »
The Timex/Sinclair went from product announcement to in stores in just under a year. And then Timex left the market.
Timex Sinclair 2068 Timeline Read More »
The TS1000 keyboard was, unsurprisingly, not the computer’s strongest feature. It required a very specific touch and was finicky. As a result, aftermarket solutions, from full replacement keyboards to “beepers”, were quite popular among serious hobbyists.
Keyboards and Keyboard Accessories for the ZX81 and TS1000 Read More »
The 1K RAM on the ZX81 was not a lot to work with. A number of programs were written to fit in the restricted space but the real solution was more memory. In addition to the Sinclair and Timex/Sinclair RAM packs, many solutions were available, up to 64K RAM.
RAM Packs and Memory Expansion for the ZX81 and TS1000 Read More »
In my previous post, I had revised my converter to use the LM1881 dedicated sync separator. Results, unfortunately, were poor. So, I went back to the data sheets for the AD724 RGB to NTSC/PAL Encoder and the LM1881 Video Sync Separator. Poring over them revealed I’d benefit from a few more capacitors. I also switched from a 3.58mhz
Adventures in 2068 Video, Part II Read More »
John Coffey wrote this note to his customers, in part to explain why it was a few months late. by John Richard Coffey I became interested in computers in 1974 when I saw some of the first Apples demonstrated at a mall in my hometown of Columbus, Indiana. I learned a little BASIC then. Later
A Brief History of JRC Software Read More »
