Texas Instruments TI-508

Date of introduction:  1989 Display technology:  LCD
New price:   Display size:  8
Size:  4.7" x 4.1" x 1.0"
 120 x 106 x 25 mm3
Weight:  3.0 ounces, 86 grams Serial No:  
Batteries:  n.a. Date of manufacture:  mth 06 year 1990 (B)
AC-Adapter:   Origin of manufacture:  Taiwan (C)
Precision:  8 Integrated circuits:  Sharp LI3135MS
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Nevertheless the identification number TI-508 points to a handheld calculator, it could be called a "small desktop" machine. The calculator is based on the earlier TI-502.

Dismantling this TI-508 manufactured in June 1990 by Cal-Comp Electronics , an OEM (Original Equipment Manufacturer) in Taiwan, reveals a clean design centered around Sharp LI3135MS single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by solar cells.

Inspecting the PCB of this TI-508 calculator brought our attention to a small mark reading SD9T-10, most likely a reference to Type Small Desktop 9, Texas Instruments and Revision 1.0 of the design (schematics and layout). We spotted this PCB-Mark already with the first TI-1795 and its near identical offspring Radio Shack EC-2006A and started compiling a list of the PCB-Marks on calculators manufactured by OEMs for Texas Instruments.

An identical calculator was sold as TI-1795 in the Americas, an identification number clearly borrowed from the desktop line. 

Production of the TI-508 and its twin TI-1795 was shifted in 1991 from Taiwan to Thailand, just before the slightly redesigned TI-508 PLUS was introduced.

Don't miss the odd TI-808 and the TI-510.


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If you have additions to the above article please email:

Joerg Woerner, December 5, 2001. No reprints without written permission.