Texas Instruments TI-508 PLUS

Date of introduction:  1992 Display technology:  LCD
New price:   Display size:  8
Size:  4.9" x 4.2" x 1.0"
 125 x 106 x 25 mm3
Weight:  3.0 ounces, 84 grams Serial No:  
Batteries:  n.a. Date of manufacture:  mth 06 year 1994
AC-Adapter:   Origin of manufacture:  Thailand (C)
Precision:  8 Integrated circuits:  Sharp LI3154
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

This TI-508 PLUS was introduced in 1992 for the European market together with the almost identical TI-1795+ for the American market. It followed the original TI-508 and still hides the secret why more or less identical calculators carry a "Handheld (TI-5xx)" or "Desktop (TI-17xx)" designation.

Dismantling this TI-508 LPUS manufactured in June 1994 by Cal-Comp Electronics in Thailand reveals a very simple construction centered around a Sharp LI3154 single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by solar cells. We noticed this chip during our research about so-called Checkbook Calculators with the Radio Shack EC-455.

Learn more about single-chip calculator circuits used in Account Manager Calculators.

Inspecting the PCB of this TI-508 PLUS calculator brought our attention to a small mark reading SD9L1-10-1, most likely a reference to Type Small Desktop 9. We spotted a very similar PCB-Mark already with the Radio Shack EC-2006A and Privileg SOLAR 31 and started compiling a list of the PCB-Marks on calculators manufactured by OEMs for Texas Instruments.

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If you have additions to the above article please email:

Joerg Woerner, January 12, 2004. No reprints without written permission.