BOWMAR MX100 ‘SCIENTIFIC BRAIN’ CALCULATOR

Description

BOWMAR MX100 ‘SCIENTIFIC BRAIN’ CALCULATOR
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CELEBRATING 20 YEARS OF SELLING ON EBAY!
BOWMAR MX100 ‘SCIENTIFIC BRAIN’ CALCULATOR
This calculator is very clean. It is being sold as is since we have no power adaptor.
No returns. We are assuming it can be repaired if needed, or can be used for parts.
Or it may work perfectly with the right power adaptor.
The calculator information and reviews as found on the internet:
The MX100 Scientific Brain (also known as Model 92001) was a calculator manufactured in 1974 by the Bowmar Corporation. There was also an identical model EC-450 that appeared later with the Radio Shack branding. The Bowmar MX100 had an 8-digit LED display with full-floating decimal-point, and could handle algebraic and scientific functions. It was a portable pocket-sized unit measuring 1 ¼ -inches × 3-inches × 5-inches, and 4-oz in weight. It had built-in rechargeable NiCad batteries providing 4-hours operation after a 7-hour charge through the supplied mains charger adapter.
Scientific functions
Built-in memory
X and Y register operations
Chain and constant operations allowed
Leading zero suppression
Overflow indicator
Low-battery indicator
Simultaneous charging and usage allowed
Reading the manual, the impression I had was that before the advent of this scientific calculator, scientists usually utilised slide rulers. I thought it was fascinating that they were able to pack such complex functions such as the sine, cosine, tangent, and their inverse trig functions in this little calculator utilising semiconductor technology of that time. This lovely little calculator can also calculate natural and common logs, exponential, square root, reciprocal, and raise y to the power of x. To achieve these functions utilising the digital technology of that time is remarkable and it truly was a scientific brain back then. This calculator utilises the A4001 IC, together with 7340, 7401, and 7402 ICs. Back then, semiconductor technology usually required large voltages including a negative rail to operate; hence, there is a small dc-dc converter circuit to produce the necessary voltage rails from the NiCad batteries.
In the U.S., the Bowmar name was generally associated with quality, and therefore when the MX100 is available for sale, it tends to be desirable. Many people dislike modern membrane keyboards and LCD displays that are barely legible, and this calculator has a clear bright LED display, with a lovely click keyboard, making it the Rolls-Royce of calculators where quality is concerned. A unit in good working order, together with the charging adapter and storage pouch can sell for over thirty pounds and more. A unit in mint condition together with its original box and accessories can of course command a higher premium depending upon the day.
These calculators are very old and consequently the built-in NiCad batteries will very likely require replacing, therefore this is one of the issues to be mindful of when buying. The following pages of this multi-page article shows the inside electronic engineering and what the batteries look like.
PHOTOS OF THE INSIDE:
https://www.petervis.com/Calculators/bowmar-mx100/bowmar-mx100-electronic-engineering.html
PHOTOS OF DISPLAY
https://www.petervis.com/Calculators/bowmar-mx100/bowmar-mx100-led-display.html
PHOTOS OF BATTERIES
https://www.petervis.com/Calculators/bowmar-mx100/bowmar-mx100-batteries.html
PHOTOCOPY OF THE ORIGINAL MANUAL:
http://www.decadecounter.com/vta/pdf/Bowmar%20MX100.pdf
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_gsrx_vers_1292 (GS 8.3.6 (1292))