Olympia SL674CK

Does this Olympia SL674CK 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. We discovered the Technico SL-674CK and its numerous offspring like IMA LC 685S, KMC 8000, Levi SL1673, MBO Solar SP20, Migros SL 671 and this Olympia SL674CK 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 Technico SL-674CK, Olympia SL674CK (basically identical to the Technico SL674CK but from a later manufacturing run) and the TI-1755 SLR to learn more about their relationship.

Dismantling the featured SL674CK manufactured in 1983 by Inventa Electronics Corporation in Taiwan reveals a clean design centered around an unknown (most likely Sharp) single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) with just a few additional discrete components and powered by five rather large solar cells.

Inspecting the PCB of the Olympia SL674CK calculator brought our attention to a small mark reading I6745A-02B compared to SL6745 of the first generation Technico SL-674CK. We assume to read the I6745A-02B PCB-Mark as Inventa Model 674, Alternative Design (Sharp chip instead of Toshiba or NEC) and Revision 02B of the PCB and more general:

We 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 16, 2020. No reprints without written permission.