Texas Instruments TI-5230

Date of introduction:  1977 Display technology:  Fluorescent
New price:   Display size:  12
Size:  12.0" x 12.3" x 3.3" Printer technology:  Thermal
Weight:  6 pounds 2 ounces Serial No:  
Batteries:   Date of manufacture:  
AC-Adapter:  120 V or 220 V Origin of manufacture:  USA
Precision:  12 Integrated circuits:  TMC0501, TMC0572, TMC0587, TMC0588, 7*TMC0598, TMC0255, TMC1376
Program steps:  200 Courtesy of:  Joerg Woerner

This rare TI-5230 seems to be an enhanced version of the TI-5225. We notice 16 added keys compared with the basic calculator but [START], [STOP] and [ENTER] are not common labels for a simple desktop calculator.

We decided to dismantle the TI-5230 to reveal its true genes and found a real surprise under the cover of the huge housing. Please watch the following 4 pictures carefully.

The internal construction of the TI-5230 is a typical design of Texas Instruments. We know the style from the TI-5225 but notice two stacked printed circuit boards (PCB's).

TI-5230_1.jpg (159896 Byte)

The lower PCB makes use of two single-chip calculator chips to control both the thermal printer and the display. TI-5230_2.jpg (143895 Byte)
The upper PCB mixes some 28-pin devices with 10 smaller devices. A known releation ship... TI-5230_PCB.jpg (155156 Byte)
Looking closer on the upper PCB gives with the TMC0501 Arithmetic chip and lots of memory a real surprise !  TI-5230_IC.jpg (116448 Byte)

With the TMC0501 building blocks Texas Instruments created a novel architecture for scalable scientific calculators. The architecture used minimum a 2 chip design with the Arithmetic chip and the SCOM (scanning read only memory) but was expandable to a maximum of 8 SCOM's, additional RAM as program memory for programmable calculators, additional RAM for general purpose registers and even a chip driving a printer. Most scientific and programmable calculators from Texas Instruments between the years 1974 and 1982 rely on these chips. Please find all known calculators using the TMC0501 architecture here.

Combining all numbers found on the integrated circuits of the TI-5230 adds to an impressive calculator:

Part Number Amount Desciption
TMC0501 1 Arithmetic chip with up to 13 digits precision based on
Chip set for scientifical calculators
TMC0572 1 Bare Read Only Memory (BROM) with 1k*13 instruction memory
TMC0582 1 Double Scanning and Read Only Memory (DSCOM) with 2.5k*13 instruction memory and 16*16 digits constants
TMC0583 1 Double Scanning and Read Only Memory (D SCOM) with 2.5k*13 instruction memory and 16*16 digits constants
TMC0598 7 External Random Access Memory for user programms with 240*8 of read/write memory (240 program steps or 30 data registers) each
TMC0255 1 Driver for thermal printer
TMC1376 1 Driver for display based on Third generation single chip calculators

Overall the complexity is centered between the well known TI-59 and the flagship SR-60A!

Printer paper:

The thermal paper used with this printer (TP-30250 2-1/2" wide and 14 Feet length) was discontinued long time ago. In 2008 Appleton (Appleton, WI) manufactured with the Alpha 800-2.4 paper still a compatible paper.

horizontal rule

If you have additions to the above article please email:

Joerg Woerner, June 11, 2005. No reprints without written permission.