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Technico SL-881

Date of introduction:  Feb. 1984 Display technology:  LCD
New price:  $19.95 (SRP 1985) Display size:  8
Size:  5.1" x 4.7" x 1.2"
 130 x 120 x 30 mm3
   
Weight:  4.2 ounces, 120 grams Serial No:  
Batteries:  n.a. Date of manufacture:  mth 10 year 1984
AC-Adapter:   Origin of manufacture:  Taiwan
Precision:  8  Integrated circuits:  
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Does this Technico SL-881 calculator look familiar to you? Inventa Electronics Corporation of Taipei, Taiwan started already in 1975 manufacturing and marketing calculators under the Technico brand. Inventa Electronics Co. is today known as Inventec Corporation, one of the World's largest manufacturers of mobile devices and computers. This SL-881 Small Desktop calculator was one of their most successful OEM (Original Equipment Manufacturer) designs, we know this product from at least eleven different calculator brands: Digitech SL881, Elco EOS-880, Hanimex SDL818, IDEA 88-2008, IMA LC 780, M-Office SL881, MBO LC 8090 SP, Omnitech SL 5000, Philips SBC 1830, Privileg Solar 30, and Sears 80. Please compare it with the OEM Design SD9 (Small Desktop 9) from Inventa's main competitor in the 80s, Compal Electronics founded in 1984 in Taipei, Taiwan.

Dismantling the featured SL-881 manufactured in October 1984 by Inventa Electronics Corporation in Taiwan reveals a rather complex design centered around a Toshiba T6853BU single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) with both the LC-Display and solar cells and connected to a second double-sided PCB for the keyboard with a short flat flexible cable (FFC).

Inspecting the PCB of the Technico SL-881 calculator brought our attention to a small mark reading I881B-01C, most likely a reference to Inventa SL-881 and Revision 01C of the design (schematics and layout). We started compiling a list of the PCB-Marks on calculators manufactured by OEMs for Texas Instruments to "Crack the Code" of the TI-1755 SLR.




If you have additions to the above article please email: joerg@datamath.org.

Joerg Woerner, April 23, 2020. No reprints without written permission.