Texas Instruments TI-1757 II

The TI-1757 II "Melody Calculator" followed the original TI-1757 "Melody Card" and added to the similar TI-1755 the capabilities to play own melodies or the "Happy Birthday..." rhyme. The music function gives 10 notes of a scale. With 2 notes below the octave and one above you can play simple tunes. Another key allows you to play either flat (b) or sharp (#). This transforms the basic key of C to F and G by flattening the B to Bb in the first case and sharpening the F to F# in the second case. Thus most tunes can be played with a little practice.

The keys are marked Do Re Mi Fa Sol La Si Do etc. 
When the calculator is playing "Happy Birthday" it is impossible to stop it or turn it off! As the individual notes decay it is possible to hear a digitized sound in the background.
John Ashton

Dismantling this TI-1757 II manufactured in or around 1983 by a non-disclosed OEM (Original Equipment Manufacturer) 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 two LR54 (LR1130) batteries.

Inspecting the PCB of this TI-1757 II calculator brought our attention to a small mark reading IO0612A-01C, we spotted a similar PCB-Mark IO0800-02D already with the TI-2130 and its twin Technico F-800. We are almost positive that the TI-1757 II and its unknown siblings were manufactured by Inventa Electronics Corporation of Taipei, Taiwan. 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, January 3, 2002. No reprints without written permission.