Texas Instruments SR-40 Prototype

Date of introduction:  Never Display technology:  LED-stick
New price:   Display size:  10 + 2
Size:  5.8" x 3.2" x 1.3"
 147 x 81 x 32 mm3
Weight:  8.1 ounces, 231 grams Serial No:  0000030
Batteries:  BP1A Date of manufacture:  wk 24 year 1975
AC-Adapter:  AC9130 Origin of manufacture:  USA
Precision:  10 Integrated circuits:  TMS1111
Memories:  1    
Program steps:   Courtesy of:  Marie Collas

We knew already the SR-40 Prototype with the impressive serial number 001P when fellow collector Marie Collas reported in 2012 the discovery of a second SR-40 Prototype in Mexico. He spent not only a fortune to acquire this rare calculator but arranged shipment directly to the Datamath Calculator Museum. Thanks!

What a surprise to discover with 0000030 a "real" serial number on the back of the calculator.

Dismantling this SR-40 Prototype manufactured in Summer 1975 reveals an identical design to the SR-40 Prototype 001P but the TMS1111 single-chip calculator circuits lacks the socket.

Interested in rare calculators with the "40" designation? Don't miss this model 40.

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Joerg Woerner, March 7, 2013. No reprints without written permission.