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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.