The quality of the Timex/Sinclair 2068 video was never great: It was something some reviewers pointed out as observable on TV screens. Modern technology has only made that more obvious. Problem One: Power One of the major contributors to poor video signal quality is the computer’s power supply. The 2068 has two internal power supplies: […]
How to Fix 2068 Video Read More ยป
It is done. I’ve “improved” the 2068 signal as much as I can via converting the RGB to composite. It’s pretty good but not perfect: there’s some ghosting and some halo, both effects of the imperfect conversion/cleaning of the composite signals. However, Don Dindang (maker of the very popular Harlequin Spectrum clone PCBs) turned me
Improved 2068 Video Converter Read More ยป
Rex Naden was vice-president of research and development at Timex during the time they produced the Timex/Sinclair 1500 and 2068 computers. He spent thirty-five years in the semiconductor industry, holds fourteen US patents and earned his BA, MS and PhD degrees in Electrical Engineering from Rice University. Naden developed his affinity for production at an
Interview with Rex Naden Read More ยป
If you read enough of the old Timex/Sinclair newsletters, you’ll notice that two printers were especially popular with 2068 owners: the Gorilla Banana/Seikosha GP-100 and the Olivetti PR-2300 “inkjet”. And you may wonder why those two printers were especially popular. A Printer Named Banana The first is easy: Seiko (a relative of Epson) produced the
2068 Users and Odd-ball Printers Read More ยป
Being retired and finished with my combat pit, I was drawn to get out my ZX81 which had been stored in a plastic tub for 25 years. I was faced with two problems: 1) I had no RF TV sets and 2) did not have a usable cassette recorder. I did the one transistor video
Minstrel 3 Review Read More ยป
The KoalaPad was a resistive touch pad made for home computers like the Apple II, Atari and Commodre 64, first released in 1983. A few years later, Zebra adapted it for use with the TS 2068. Ironically, the KoalaPad’s ancestor, the PrestoDigitizer, began as a product for the Sinclair ZX-80 and other microcomputers. Innovision PrestoDigitizer
The KoalaPad Comes Full Circle Read More ยป
QZX was one of the longest running Sinclair newsletter in the United States, starting in 1981 and published for more than ten years. Many Sinclair computer users never heard of it because it was a special purpose newsletter devoted to the use of Sinclair computers in radio. Most subscribers were amateur radio operators and were
The History of QZX Read More ยป
After Timex exited the market, they disposed of excess inventory as quickly as possible. Parker Electronics incorporated the T/S 1500 into a HVAC controller for Carrier installations. According to a brief mention in the VISTA Newsletter, Parker “used T/S 1000s as control devices and 2040 printers for read-outs.” The company went to the trouble of
Parker Electronics/Carrier Command Center Read More ยป
Lynd Church goes to Scotland to discover just how the ZX-81 is manufactured. In keeping with its philosophy of sub-contracting all manufacturing processes, Sinclair Research appointed Timex to produce the ZX-81 when it was introduced in March 1, 1981.Since that time, production at the Timex plant at Dundee has increased from 10,000 to 60,000 units
A piece of cake in Dundee Read More ยป
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
The Lambda PC8300 Read More ยป
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 ยป
Reprint of an article about a medical practice program written by a practicing ophthalmologist.
ZX81 in an Ophthalmologist’s Office Read More ยป
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 ยป
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 ยป
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 ยป
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 ยป
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 ยป
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 ยป
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 Iโd benefit from a few more capacitors. I also switched from a 3.58mhz
Adventures in 2068 Video, Part II Read More ยป
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 ยป
