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Texas Instruments TI-10 Profit Guide

The TI-10 Profit Guide looks familiar to us and seems to be a mix of the basic TI-1746 with the calculating functions of a BA-20 Profit Manager missing the clock module.

Three special percentage calculations are implemented with six extra keys:

• Calculation of cost limit for given selling-price and a targeted margin (CST column of extra keys):<selling-price> SEL <target margin> MAR => cost
limit• Calculation of required selling-price for given cost and a targeted margin ( SEL column of extra keys):<cost> CST <target margin> MAR => required
selling-price• Calculation of achieved margin for given selling-price and cost ( MAR column of extra keys):<cost> CST <selling-price> SEL => achieved margin |

**
**Dismantling
the featured TI-10 Profit Guide manufactured in July 1986 by
Inventec Corporation in
Taiwan reveals a typical design of OEM (Original Equipment Manufacturer) calculators
developed in the 80s. Unfortunately the calculator chip is soldered in reverse
on the printed circuit board (PCB) but we suspect it is the Sharp LI3163 used
with the BA-20 Profit Manager, too.

Inspecting
the PCB of this TI-10 Profit Guide calculator brought our attention to a small mark reading
**IOTI10-02A**, we spotted similar PCB-Marks already with the
TI-1796 and
TI-1798 manufactured in 1986, too. We started compiling a list of the
PCB-Marks on calculators manufactured by OEMs for Texas Instruments.

The designation TI-10
was used in 2002 again for a scientific calculator.

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

© Joerg Woerner, June 9, 2004. No reprints without written permission.