Addo
Addo and Addo-X
Anthea Agrell has kindly provided the following information about Addo:
"My grandfather, Hugo Agrell, founded Addo AB in Malmö, Sweden in 1918. My father took it to the US in 1950. As far as I know the company in the UK, in Cirencester, was a subsidiary of the Swedish company where my uncle became the MD.
What I do know with certainty is that my grandmother received the ceremonial keys to the town of Cirencester - where the factory which manufactured the machines was located - as a token of their enthusiasm that jobs were being created. I also remember the name of the British agents as being Ian Bulmer and his brother. They were located in London. I believe they did a pretty good job since as late as 1990 Addo-X's were still in use !"
Addo are mainly known for their mechanical calculators. The full-keyboard machines have the name Addo and the 10-key machines have the name Addo-X (X from the Roman numeral for 10, maybe). However, they did have a few models of electronic calculators:
- Addo Ten/3.
- Addo-X 9354J was made in Japan and is similar to the Sharp QT-8D.
- Addo-X 9364 was made in Japan and is similar to the Sharp EL-8.
- Addo-X 9675, described below, was manufactured in Britain.
ADDO-X 9675
Addo-X 9675
Power source - AC.
Display is 10 digits, "Nixie"- type tubes.
4-functions, %, memory.
Main integrated circuits - Plessey 7-item chipset with MP931B, MP932B, MP933B, MP934B, MP935B, MP936B, MP937B.
275 x 197 x 97 mm (11.8" x 7.75" x 3.8").
Made in the United Kingdom.
Made about 1972.
Here the cover has been removed to reveal the "Nixie"-type tubes, with display-driver board behind under the power supply, and the main calculating board right underneath.
The main calculating board with the 7-piece chip-set manufactured by Plessey.
This is one of the few calculator chip-sets manufactured by Plessey. It looks to be quite costly since it requires 7 ceramic encased integrated circuits. This calculator is believed to date from about 1972, and by then both Mostek and Texas Instruments were putting the electronics of a 4-function calculator in one small plastic encapsulated integrated circuit. So a chip-set like this would then not have been competitive.
Plessey was a major company in Britain involved in radio and television-chassis production, but is especially noted for being at the forefront of developments in electronic telephone exchanges throughout the 1960s, 1970s, and 1980s. It was taken over by GEC-Siemens in 1989.
