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Diablo HyType II

In my youth in the mid 80ies my father brought home an old word processing system made by Logica. It had a multbus cardcage with 8080 processor. It also had a big daisy wheel printer. The system was scrapped for parts to play with but the printer was left untouched for some reason. Now 30 years later I found it a bit more dusty and with some light rust.

When looking into it I found that it had som interesting mechanics and thought it could be interesting to revive this poor thing.


Before starting the restoration I did some research on Diablo as a company and the HyType II printer. While doing this I found an interesting document, Oral History of George E Comstock, one of the founders of Diablo Systems Incorporated. The interview had been done by Computer History Museum in California, USA. It had some interesting details on the start of the company and the invention of the Daisy Wheel printer. 

Diablo was founded in 1969 by George E. Comstock. Wikipedia mentions some more people being involved in founding the company but the document above does not give a clue in. It might be likely that there were some other people levaing Friden (the calculator maker) and joining the new startup company. The outset from the very beginning was to make disk drives and printers. Already at Friden George E. Comstock and his team had been working on disk drives and and since Friden also was involved in printing terminals, various aspects of printing technology was well known. 

The daisy print wheel was prior knowledge at this time. Fredrick P Wilcox had patented an equipment with using a daisy wheel already in 1960. (US patent #3,461,235). This printer was based on a continuously rotating wheel. Comstock and his team did some work with this type of technology at Friden but recognized that the continuous movement was a problem to get a reliable and fast printer.

The the man who solved this problem was the Hungarian born Dr Andrew Gabor. He created a servo controlled positioning system to control both the wheel movement and carriage movement. For this he were awarded two patents (US patent #3,663,880 and #3,954,163). The same tape of servo controlled system that Andrew Gabor designed was used in the highly successful disk drive manufactured by Diablo.

Already in 1972 Xerox decided that the want to purchase the entire company which became a part of Xerox.

While comparing the history presented in the interview above and what is written on Daisy Wheel printing technology it is apparent that something has gone wrong. Wikipedia claims that David Lee is the man behind the Daisy wheel technology. According to the interview he joined 1971 when the printer was production ready. The fact that Andre Gabor holds two patents also speaks against this claim. 

For technical details it was just to check the usual goto when it comes to old technical documents, bitsavers. I found the technical manual as well as the schematic for the power supply there.

Dirt and rust removal


Plenty of dust due to 30 years in storage. Some steel parts had light rust as well. The old grease was hard. Blowing away dust and then degreasing liquid made it look better. The rust remover on rusty parts.

Powering up