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DATAMATH CALCULATOR MUSEUM

Texas Instruments TI-1000 (silver)

Date of introduction:	1978	Display technology:	LED-stick
New price:	$9.77	Display size:	8
Size:	5.4" x 2.8" x 1.3" 138 x 72 x 32 mm³
Weight:	3.0 ounces, 84 grams	Serial No:
Batteries:	9V	Date of manufacture:	wk 43 year 1978
AC-Adapter:	AC9180	Origin of manufacture:	USA (LTA)
Precision:	8	Integrated circuits:	TMC1992
Memories:
Program steps:		Courtesy of:	Joerg Woerner
		Download manual:	(US: 0.8M Bytes)

While the original TI-1000 introduced in June 1977 sports a golden trim around the keyboard, changed Texas Instruments the design in Summer 1978 to a silver-gray finish.

Dismantling both generations of the TI-1000 reveals a surprise! The earlier model uses an internal construction with a small printed circuit board (PCB) similar to the TI-30 while later model looks with its larger flexible PCB more like a TI-50. The picture shows on the left a TI-1000 manufactured in 1977, the TI-1000 on the right was assembled in 1978.

The most important difference are the two single-chip calculator circuits used with the early and later TI-1000s:

• TI-1000 (1977): TMC1991 packaged in 28-pin SPDIP (Shrink Plastic Dual In-line Package) with Die-up (standard pinout) on a two-sided Rigid-PCB
• TI-1000 (1978): TMC1992 packaged in 28-pin SPDIP (Shrink Plastic Dual In-line Package) with Die-down (reverse pinout) on a single-sided Flex-PCB

The use of a single-sided PCB was made possible with an unconventional approach of scanning the keyboard switch-matrix with 10 dedicated pins (6 row outputs, 4 column inputs) instead of using either the digit-driver outputs or segment-driver outputs for the keyboard rows.

Calculators with different keyplates were sold from Western Auto as Citation.

The two different internal designs of the TI-1000 calculators are used with the Little Professor (1978), too.

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