Commodore Minuteman 1

Date of introduction:  1972 Display technology:  LED modules
New price:  $118.00 Display size:  8
Size:  6.0" x 3.5" x 1.7"
 153 x 90 x 44 mm3
Weight:  15.4 ounces, 436 grams Serial No:  28378
Batteries:  6*AA NiCd Date of manufacture:  mth 06 year 1972
AC-Adapter:   Origin of manufacture:  USA
Precision:  8 Integrated circuits:  TMS0103
Program steps:   Courtesy of:  Joerg Woerner

The Commodore Minuteman 1 followed immediately the Commodore C110, based on the famous Bowmar 901B.

Minuteman1_Label.jpg (69100 Byte)"The Minuteman 1 was the world's first solid-fueled Intercontinental Ballistic Missile (ICBM), and has been the mainstay of the USAF's ICBM force ever since its deployment. Because international arms reduction treaties...." Mark Wade, 2003.

These are first the words of an introduction to the Minuteman 1 missile developed by Boeing in the early 60s. But here we are talking about a very odd calculator manufactured by Commodore Business Machines, Inc. in Santa Clara, California.

Minuteman1_1.jpg (13411 Byte)The Minuteman 1 nicknamed "MM.1" is a big calculator, compared with the sleek Bowmar 901B it adds about 50% of weight and outperforms it in all dimensions. The side-view of the MM.1 gives a good impression of the sheer size.

Minuteman1_Div.jpg (96806 Byte)Exploring the roots of the Minuteman 1 is a funny exercise. Without any tools the two halfes of the housing could be separated. This is accomplished with an additional connector between the batteries and the calculator electronics.

Minuteman1_Compare.jpg (125825 Byte)Removing the coverplate of the front-housing reveals a big surprise. The main printed circuit board (PCB) of the MM.1 is identical with the Bowmar 901C and carries even the original Bowmar part number PM901-400/E.

Minuteman1_Display.jpg (71070 Byte)Turning over the calculators shows some differences between the MM.1 and the Bowmar 901C. The MM.1 makes use of discrete LED-displays manufactured by Texas Instruments, Bowmar relies on their own Opto-stic displays. Please notice the different placement of the switches.
Karl Schmitz - proud owner of two MM.1 reported that they used the Opto-stic display, too. 

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If you have additions to the above article please email:

Joerg Woerner, September 29, 2003. No reprints without written permission.