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Calculators: Handheld: Commodore SR-9120D
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Size (approx): | 75mm x
140mm x 30mm (max) (w,h,d) Weight 130g excluding batteries |
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Power: |
9.0V DC, 1 x PP3 size battery. Accepts an adapter/charger (DC640, 7070 or 709) through a socket on the right hand side, about mid way up. | ||
| Case: | A little more style than the normal Commodore button monsters. Two-piece case in matt and smooth black plastic with lots of sculpturing on the edges. It even has its own ledge for the CBM logo which is a reversed out printed metal plate in a recess. Bright and cheerful coloured keys are squishy but very positive. Additional key labelling is raised and printed green but has not survived very well. | ||
| Display: | 10+2 red LED display (with a third and fourteenth for negative sign and error indication) with single linear lens. | ||
| Features: | Standard four functions with change sign, pi, register exchange, reciprocal, square root, nth root, squares, powers, logs, trigs, standard deviations, degree/radian, polar-rectangle coordinates, twin memory, parenthesis and exponents. | ||
| Age: | 1975 | ||
| Manufacturer: | Commodore Japan Limited, made in Japan, ref 200640-02 serial No. 09112. | ||
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Comments:
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A massive 39 keys and stuffed full of useful functions. Lovely flat LED display but the lack of error recovery is unforgivable. The "12" in the model number refers to the number of digits as you could get a 9 or 14 digit version as well. The original case is shaped soft black plastic with popper closing at the top. It is embossed with the Commodore logo on the front and Made in Japan on the back. |
| Components: | 1 x cpu: Commodore GHU-02A 7531
(week 31 of 1975), 40 pin DIL 1 x IC: Commodore GHU-01A ESR N 7531, 8 pin DIL 1 x display driver ICs: ITT 546A-5N (7525 and 7524), 16 pin DIL 1 x 14 digit LED display module 1 x capacitor 1 x resistor |
| Boards: | The keyboard board is attached to the front. The main cpu board (ref PCB 200708) sits loosely on top and is connected via a 21-way ribbon cable. |
| Construction: | Remove the two screws at the bottom rear of the case and gently squeeze in the front piece to lift off the back. |
| Logic comments: | The (C) key operates as a cancel entry function on the first press whilst a second press will clear the calculator |
| Input overflow is suppressed, inputting an eleventh digit is ignored | |
| Negative numbers are shown with a "-" in the far left (fourteenth) digit thereby allowing full ten digit negative numbers. Negative exponents are shown with a "-" in the third digit. | |
| There is no constant function | |
| Divide by zero shows "E" in the fourteenth digit and is not recoverable | |
| Overflow shows "E" in the fourteenth digit and is not recoverable | |
| There is no indication of memory - you have to remember it |
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The manual measures 148mm x 82mm and is printed
one colour, black. It has extensive examples, formula and conversion
tables in its 64 pages. Ref. 200654-01, printed in Japan.
It covers a number of similar models; the 14, 12 and 9 middle numbers being the number of display digits. The D and R suffix standing for disposable or rechargeable (internal) batteries. |
