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Texas Instruments TI-58C Pool Water Analysis

Date of introduction:	1979	Display technology:	LED-stick
New price:		Display size:	10 (8 + 2)
Size:	6.4" x 3.2" x 1.5" 162 x 81 x 37 mm³
Weight:	8.5 ounces, 240 grams	Serial No:	7183855
Batteries:	BP1A	Date of manufacture:	wk 17 year 1979
AC-Adapter:	AC9131	Origin of manufacture:	USA (ATA)
Precision:	13	Integrated circuits:	TMC0501E, TMC0580 (CD2400), TMC0580 (CD2401), TMC0573, TMC0591, RCA 10341XX TMC0540 (ZA5539)
Memories:	0-60
Program steps:	480-0	Courtesy of:	Mark Bollman
		Download manual:	(US: 3.5M Bytes)

The main disadvantage of the TI-58, non-permanent program storage, was corrected with the TI-58C. Replacing the two TMC0598 MULTI-REGISTER chips of the TI-58 manufactured in a power-hungry PMOS process with a low-power CMOS RAM (Random Access Memory) chip, battery drainage caused by the NiCd batteries itself was quicker than drop caused by powering the RAM.

The TI-58C continued the usage of the Solid State Software Modules™ with up to 5000 program steps introduced with the TI-58 and TI-59 already in 1977. On the backside of the TI-58/59 you'll notice a small lid with a place for a module. The Master Library with 25 different programs was included, a lot of other modules were available.

We know five different approaches of the module expansion:

• Standard modules like the Master Library use only the small sticker
   above the A,B,C,D, and E keys.
• Other modules like this Pool Water Analysis developed by Olin Corporation
   make use of a colorful keyboard mask.
• Customized calculators like the USMC AV-8C calculator or insurance calculators
   sold by Allianz and others use special keyboard arrangements.
• The CAL-Q-TAX calculator uses an extender instead the usual drop-in modules.
• The Kodak Q-700 Program Adapter makes use of a snap-on cover with
   an individualized printing.

Dismantling the Pool Water Analysis calculator reveals a standard TI-58C calculator manufactured in Spring 1979. It is one of the very early models, the printed circuit board (PCB) of the calculator was manufactured in Canada and makes use of some blue wires.

The calculator was available till the year 1983.

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