Texas Instruments (TI) SR-10
In the end of 1972, Texas Instruments
launched the first scientific pocket calculator, which was made in several versions.
The SR-10 displayed here belongs to the second version, which was made in Italy.
This version carries the "SR-10" logo on the keyboard plate.
The SR-10 offers an inside view, which is typical for pocket
calculator of that age: Inside, there's a case-filling PCB, on which a handful of
ICs (TMS 0120NC as CPU and four display driver SR75494N, which were made in
December 1973), many transistors and even more diodes and resistors are mounted.
Unlike the other simpler pocket
calculators, the SR-10 offered an extended calculating range (up to 10^99) and
a square and square root function. The entries are made by standard algebraic entry
logics, where at the end of a calculation, the "=" key has to be pressed. A wrong
entry can corrected by the "CD" key.
|inside and batteries|
The SR-10 works with three NiCD accus, which can be loaded by an external
power device. The socket is secured against wrong poling by a diode.
Unfortunately in the SR-10 displayed here, the accus (the original ones as well as
the replacement accus) leaked and did not only corrode the contacts, but damaged the
electronics so much, that only the pattern 0.0.0.0.0.0.0.0-00 is displayed - maybe
this is familiar to you and you can help in restoring my SR-10?
|does not work any more...|
|Manufacturer||Texas Instruments (TI)|
|Display||8+3 digit LED|
|Number of keys ||23|
|Functions||+-*/ INV SQRT SQR|
|Power supply ||3xAA (internal)|