Vintage 1974 Bowmar MX90 Calculator complete & works, box charger case papers

Description

This item is a Bowmar MX90 Electronic Calculator.  It is in excellent condition in every way and fully functional.  All the keys work fine and all have a consistent feel and sound.  The Bowmar 11 position (10 digits plus sign) "Optostic" LED display is in perfect condition and still very bright.  The internal NiCad batteries have been replaced with three Tenergy 1000mAh NiCad cells that have been fit into the original six position AA battery holder that screws into the bottom half of the MX90 calculator.  Earlier Bowmar calculators used six NiCad cells but later models such as the MX90 that used only three cells still used the original six position hardware.  It comes with the zippered carrying case which is in excellent condition inside and out.  The original Model B901-077-4 wall charger with the very odd polarity plug that fits perfectly into the calculator is included.  The charging port pins have been polished to a bright finish again to make good contact (see last picture).  There is also the original box, instruction booklet, accessories order form and charging instruction card which are all in excellent condition.  The instruction booklet has all of its pages with no tears, rips or writing inside.  The only non-original item is the cardboard carrier for the wall transformer which was made to be very similar to the original missing piece.  All pictures are of the actual items you will receive.  Ships via USPS Priority mail with tracking.
Bowmar was the first manufacturer of small hand held calculators in the U.S.  Their first calculator design (the 901B) was just meant to showcase their "Optostic" red LED (light emitting diode) numeric display.  However, it was so impressive that they began producing it in large volume starting in 1971.  In the first few years of producing calculators, their revenue increased by over 20 times.  However, by the time the MX90 was released in 1974, competition between a then crowded field of competitors was taking its toll on Bowmar, especially with Texas Instruments who was both a supplier of parts to Bowmar as well as their competitor since they had realized a lot of money was to be made selling calculators too and not just the chips.  By 1976, Bowmar had filed for bankruptcy, their fall from dominance in the market just as fast as their earlier rise.  In 1974, the MX90 list price at one point was the same as the Buy-it-Now price listed for this item, .99.  A year later in 1975, it could be had for not much more than a third of that.