DATAMATH CALCULATOR MUSEUM
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DATAMATH CALCULATOR MUSEUM |
Radio Shack EC-300
| Date of introduction: | 1974 | Display technology: | LED-modules + lens |
| New price: | $114.95 | Display size: | 8 |
| Size: | 5.8" x 3.5" x 1.9" 148 x 88 x 48 mm3 |
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| Weight: | 6.7 ounces, 191 grams | Serial No: | 300-17186 |
| Batteries: | 4*AA | Date of manufacture: | wk 20 year 1974 |
| AC-Adapter: | Origin of manufacture: | USA | |
| Precision: | 8 | Integrated circuits: | WD LC1552B |
| Memories: | 1 | ||
| Program steps: | Courtesy of: | Mike Sebastian |
This
EC-300 does not look like a Texas Instruments product and made a great design
evolution compared to the earlier EC-200.
If
we dismantle this calculator, one question will immediately arise: Which company
manufactured this EC-300? Searching the single-chip calculator circuit reveals a
great surprise: The huge IC carries the logo of Western
Digital and is one step ahead the TI chips of that era:
The TI-2550 with similar
complexity (%-key and 4-key memory) was introduced later. Maybe TI had a delay
in the development of the TMS0601, the direct counterpart of the Western
Digital LC1552 used in
the EC-300 and the Montgomery Ward P8P.
Interesting note: Bowmar used with the MX55 the same
chip for a calculator without memory. The keyboard of the calculator is a mixture of the TI-1500
keys and the grid of the Datamath.
In
2001 we were indeed not sure who manufactured the EC-300. The owner of this wonderful
EC-300, Mike Sebastian noticed
a small indicator in the manual of his calculator:
We know this address! Just compare it with the well known Texas Instruments consumer service facilities of the year 1974 and found on a SR-10:
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Texas Instruments Service Facility |
Nevertheless,
this is the Service Center - maybe TI offered just the repair service for Radio
Shack. In 2003 we finally found the answer when we explored the EC-1000,
a desktop calculator matching the design line of this EC-300. This calculator
looks and feels like a TI product but carries no TI logo inside. The secret of
both calculators is a magic number on the printed circuit board (PCB): 13-04-709-479
- read more here.
The battery compartment of the EC-300 sports a small sliding switch to select between "RECHARGABLE NI-CD BATTERIES" and "ALL OTHER BATTERIES". This switch prevents the AC-Adapter from providing a charge to the batteries if the switch is set to "ALL OTHER BATTERIES".
Datamath™ is a trademark of Texas Instruments.
Known serial numbers:
A2 300-02184, A2 300-17186, A2 300-20385
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.