Commodore Minuteman 2 (Version 1)

Commodore Business Machines (CBM) introduced with the C110 already in September 1971 their first portable electronic calculator, actually a rebranded Bowmar 901B, better known as Bowmar Brain.

While the C110 was a rather short-lived product, did it pave the way to an incredible success story. Its successor Minuteman 1 was introduced within just a few months and started a completely different design language but still using Bowmar electronics. The next evolution - consequently named Minuteman 2 - replaced first the Bowmar electronics and then the Texas Instruments Klixon™ keyboard with Commodore's own designs. It took another iteration with the Minuteman 2SR to drop even the Texas Instruments calculator chips and replace it with a design from MOS Technology, a company Commodore acquired in October 1976 and fueling in October 1977 a revolution with the PET2001 (Personal Electronic Transactor), the best selling "Personal Computer" of its time.

The next iteration of Commodore's design language was introduced in 1974 with the Minuteman 3 series of calculators.

Dismantling the featured Minuteman 2 (MM.2 Version 1) manufactured in June 1972 by Commodore reveals a major change compared to its predecessor MM.1. While the the MM.1 made use of the electronics known from the Bowmar 901C, uses this MM.2 a printed circuit board (PCB) with a bold mark reading RAVEN 11870.

The main components of the two calculators are pretty similar but Commodore dropped with the MM.2 the [D] button for the power-saving mode and covered the respective key on the Texas Instruments Klixon™ keyboard with a sticker.

The display module of the MM.2 looks familiar to us, it is still using an array of 9 Monsanto MAN-3A 7-Segment LED modules.

In an additional effort to reduce manufacturing costs of their offerings, Commodore even changed the charger power supply design and replaced the original Bowmar chargers with a much more compact MM-Type A product.

Klixon™ is a trademark of Texas Instruments.

If you have additions to the above article please email: joerg@datamath.org.

© Joerg Woerner, October 30, 2021. No reprints without written permission.