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Calculators: Handheld: Commodore 776M
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Size (approx): |
65mm
(max) x 137mm x 24mm (max) (w,h,d) Weight 84g excluding batteries. |
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Power: |
9.0V DC, 1xPP3 size battery. It accepts adapter (DC-620 or 505) through a socket on the left hand side, about mid way up. | |
| Case: | Two piece dark brown and beige matt plastic case with black keyboard surround. Silver painted raised logo has survived rather well. The red convex plastic display filter is heavily inset and gives a bright image but with a limited angle of view. Just below the display is a black printed metal plate with company name that sits in its own recess. Coloured keys are wobbly and squishy but positive enough. | |
| Display: | 7 digit red LED with bubble lens and no eighth digit | |
| Features: | Basic four function with three function memory and percentages. | |
| Age: | 1975 | |
| Manufacturer: | Commodore Business Machines Inc., Palo Alto, California. Serial number 484121. Made in USA. | |
| Comments:
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This tall slim shape was used for many early Commodore calculators - primarily to cope with the bulk of the battery at the top.. Box creaked a bit when squashed and the buttons feel squishy but work well enough. Bold three-colour button system works well but the functions are basic. The 15pp manual (minus guarantee return page) was not worth scanning in. Supplied without battery and a 90-day guarantee. The logic is sound but lack of a constant function annoying and arduous memory system a pain |
| Components: | 1
x cpu: Commodore GRBP-67 7549 (week 49 of 1975) 24 pin DIL,
0.6" width 1 x display driver ITT 546a-5N 7535, 16 pin DIL 1 x 9 digit LED with bubble lens display unit |
| Boards: | The keyboard board (Ref 200 467 Commodore 1 750 916) is fixed to the front via three screws and two rivets. It is attached to the main cpu board (Ref: PCB 200864 TW-17 Rev A) |
| Construction: | From the rear remove the single screw in the battery compartment. Gently push aside the two lugs in the recesses and remove the back which is hinged from the top. You will then have to loosen the adapter socket to hinge out the main cpu board. |
| Logic comments: | (C) is used once to cancel the last number entered and a second time to clear the whole calculator. |
| There is no constant on any function | |
| Input overflow is suppressed, inputting an eighth digit is ignored | |
| Negative numbers are shown with a "-" in the immediate left hand digit as there is no eighth digit you are not allowed seven digit negative numbers. | |
| Divide by zero shows "E000000" (no decimal point) and is recoverable by dividing it by 1 | |
| Overflow shows the result with "E" (negative or positive) in the left most (seventh) digit and is recoverable by continual division by 10 (or a multiple) | |
| Memory is not indicated - you have to remember it | |
| To enter data into the memory use (=)(M), to add use (+)(M)(=)(M) to subtract use (-)(M)(=)(M) to clear use (0)(=)(M) | |
| The percentage key divides the result by 100 and can be used to recover overflows. |
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This calculator-sized box measures 140mm x 68mm x 28mm (H x W x D) and is printed in three colours with a "jazz-tech" image. This particular example has printed model number on the top flap. Made in USA. |
