Additional Pictures 


This SR-51 Prototype was manufactured in November 1974 by Texas Instruments.

The Main printed circuit board (PCB) of a SR-51 calculator. The brain of the
calculator uses the TMC0501 and a stack of 2 SCOM (TMC0522,523) circuits. 
A second PCB holds the keys, display and driver circuits.

The Display and Keyboard PCB of the SR-51 Prototype with two
TI SN27882 display drivers and fourteen 7-segment LED-Displays. 

The PCB of this SR-51 Clear-Case Prototype reveals production codes 
of week 44 year 1974 on the SCOM chip holding the firmware.

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If you have additions to the above article please email:

Joerg Woerner, November 18, 2018. No reprints without written permission.