Tektronix Model 21 Calculator
The Tektronix Model 21 was basically a MOS/LSI technology re-implementation
of the Cintra/Tektronix 909
calculator developed by Cintra Corporation of Sunnyvale, California.
The Cintra 909 was introduced in November of 1969.
In May of 1971, Cintra was experiencing some financial difficulties,
and the company was acquired by the famous electronic instrumentation
company Tektronix, Inc. of Beaverton, Oregon. Tektronix began selling
the 909 calculator under the Tektronix brand. Not long after acquiring
Cintra, Tektronix began a program to
develop its own calculators. In August of 1973, Tektronix introduced both the
Model 21 and Model 31 calculators.
The Model 21 was a scientific calculator with simple learn-mode
programmability and the ability to store and load programs on magnetic
strips. Tektronix did not find much success in the rapidly changing calculator
marketplace, and exited the market late in 1974. The Model 21 was not a
strong seller, leaving Tek with a large surplus of unsold machines which were
unceremoniously destroyed as a write-off. The Old Calculator Museum is
looking for any examples of the Tektronix Model 21, working or not, as well
as any documentation or sales literature.