How to Fix 2068 Video

How to Fix 2068 Video

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:

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Interview with Rex Naden

Interview with Rex Naden

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

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Minstrel 3 Review

Minstrel 3 Review

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

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The History of QZX

The History of QZX

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

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A piece of cake in Dundee

A piece of cake in Dundee

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

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The Lambda PC8300

The Lambda PC8300

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

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A Temporary Setback

A Temporary Setback

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

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