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Technico SB-847

Date of introduction:  1985 Display technology:  LCD
New price:   Display size:  8
Size:  6.4" x 4.0" x 0.45"
 162 x 102 x 12 mm3
   
Weight:  3.7 ounces, 105 grams Serial No:  
Batteries:  LR54  Date of manufacture:  mth 09 year 1985
AC-Adapter:   Origin of manufacture:  Taiwan
Precision:  8  Integrated circuits:  
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Does this Technico SB-847 small desktop calculator look familiar to you? Yes, it is another variation of the SB-1027 sporting an 8-digit LC-Display and dropping the "MARK UP" functionality. Both were manufactured by Inventa Electronics Corporation of Taipei, Taiwan a leading calculator manufacturer in the Seventies and today better known as Inventec Corporation, one of the World's largest manufacturers of mobile devices and computers.

We discovered the SB-1027, and most important the SL-674CK, on our quest to learn more about the roots of the TI-1755 SLR introduced in 1983. While we found proof that TI-1754, TI-1755, TI-1756 and TI-1757 II are actually rebranded Inventa calculators, doesn't fit the TI-1755 SLR into the line. We decided for a thorough tear-down of the SL-674CK and the TI-1755 SLR to learn more about their relationship.

Dismantling the featured Technico SB-847 manufactured in September 1985 by Inventa Electronics Corporation in Taiwan reveals a clean design centered around an unknown single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by five solar cells and a small LR54 (LR1130) backup battery.

Inspecting the PCB of the Technico SB-847 calculator brought our attention to a small mark reading IO0847-02B. We found a similar PCB-Mark reading I074F-02B with the LC-741CK and started compiling a list of the PCB-Marks on calculators manufactured by OEMs for Texas Instruments.



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

Joerg Woerner, April 6, 2024. No reprints without written permission.