Additional Pictures 


This early TI-81 with the Date code I-0991 was manufactured by Inventec in Taiwan
in September 1991. Please notice the missing backup battery.  

The PCB (printed circuit board) of the TI-81 manufactured  
in September 1991 looks different from the later calculators.

The main components of the TI-81: Toshiba T6A43 Application Specific CPU,  unknown 1991 ROM and Sharp LH5160 RAM. All Integrated Circuits of the main PCB were manufactured not later than April 1991.

This early TI-81 graphing calculator makes use of three display drivers :
Two T7778A column drivers and one T7900 row driver.

horizontal rule

If you have additions to the above article please email:

Joerg Woerner, March 16, 2009. No reprints without written permission.