Texas Instruments TI-58C (1980)

Date of introduction:  1980 Display technology:  LED-stick
New price:  
 $90 (October 1981)
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:  7899113
Batteries:  BP1A Date of manufacture:  wk 35 year 1982
AC-Adapter:  AC9131 Origin of manufacture:  USA (ATA)
Precision:  13 Integrated circuits:  TMC0501E, TMC0580 (CD2400), TMC0580 (CD2401), TMC0573, TMC0591, Toshiba TC5047AP or NEC uPD445L
Memories:  0-60    
Program steps:  480-0 Courtesy of:  Joerg Woerner
Download leaflet:   (US: 2.0M Bytes) Download manual:  

TI-58C_BACK.jpg (531416 Byte)The main disadvantage of the TI-58, the non-permanent program storage, was corrected with the TI-58C. Using a low-power CMOS memory (a Toshiba TC5047A in this machine), battery drainage caused by the NiCd batteries itself was quicker than drop caused by powering the memory.

TI-58C_PCB.jpg (338295 Byte)The featured calculator manufactured in August 1982 carries a different chip set compared to the TI-58 but the technical data were identical. Read more about your first steps of programming this calculator here

If you are interested in the calculating accuracy of scientific calculators don't miss the Calculator forensics.

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 note 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 four 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 the 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 and incotax calculators use an extender instead the usual 
    drop-in modules. 

The TI-58C carries the connector to the printing cradle. It seems to work on the  PC-100C revision.

American Micro Products introduced with the Module Selector a very interesting product fitting into the charging bay of the printing cradles.

The calculator was available till 1983 before it was discontinued and replaced with the TI-66 Programmable. Don't miss the rare and innovative Franken-Calculator Data Dimensioner.

Andreas Gerlich scanned recently the German documentation of the TI-59, please visit his website. Thanks!

Fellow calculator collector Marek Czeszek prepared wonderful Step-by Step Instructions how to clean a TI-58C.

The TI-58C is featured in the Texas Instruments Incorporated bulletin CL-414 dated 1978.

Find here an excerpt from the Texas Instruments Incorporated leaflet CL-199J dated 1981:

TI Programmable 58C

Advanced programmable calculator with plug in Solid State Software* and Constant Memory*.

Features TI’s exclusive Solid State Software*, tiny, pre-programmed modules you slide into the calculator to extend power, flexibility, and range. It is also keyboard-programmable. Constant Memory* feature retains data and program information even when off.
There are many computer-like features: 170 functions and operations to program up to 480 steps or 60 memories (increases to 5000 more steps with modules). With 4 types of display testing, 6 levels of subroutines, plus 9 levels of parentheses, it can handle almost any problem.
Personal Programming shows how to get the most from the 58C.

* Registered Trademark of Texas Instruments Incorporated

© Texas Instruments, 1981

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If you have additions to the above article please email:

© Joerg Woerner, December 5, 2001. No reprints without written permission.