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Calculators: Handheld: Commodore GL-979D
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Size (approx): | 75mm x
140mm x 28mm(max) (w,h,d) Weight 128g excluding batteries |
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Power: |
3V DC, using two x AA size batteries. Does accept an adapter but remove batteries first (DC-420B, 2mm plug, centre positive) through socket on the right side in the middle (a bit of an odd position). | ||
| Case: | Three piece sturdy case in black and white matt plastic. The top front has an oversized green plastic display filter that is flush with the case an has a sloping inset section. It gives a bright image and it has the Commodore logo raised and painted silver along with the words "Custom Green Line". Bold red, white and blue keys have their own raised surrounds. They keys are wobbly and squishy but work well enough. Below the keyboard is a black printed metallic sticker with the company name, which sits in its own recess. | ||
| Display: | 7 digit green VFD, with no eighth digit | ||
| Features: | Standard four functions, percentages, reciprocal, square, register exchange, and one function memory. | ||
| Age: | 1975 | ||
| Manufacturer: | Commodore Japan Ltd, made in the Japan, serial No. 69309 label part no. 200557-02. | ||
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Comments:
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Typical member of the Custom Green Line series but this one with smaller even keys and a few extra function. Solid logic but odd memory system. The lack of an extra digit limits it to six digit negative numbers which is a shame as the display has all eight digits present.. |
| Components: | 1 x cpu: Commodore GRBP-67 7540
(week 40 of 1975) 24 pin DIL 1 x 8 digit single round tube VFD display 2 x transistors 6 x diodes 5 x capacitors 2 x SIL resistor arrays 4 x resistors 1 x transformer |
| Boards: | The keyboard board (Ref: KB-6384-01 HM-23-10-RCB is fixed to the front with 10 screws and has numerous link wires. It is connected to the main cpu board (Ref: PCB200432 ART-200433 Rev-B) with a 14-way ribbon cable |
| Construction: | Remove the two screws from the back of the case. Gently squeeze the cream plastic sides and the back will separate eventually. You have to loosen the adapter socket to lift 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 functions | |
| 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 limited to six digit negative numbers. | |
| The (M) key recalls the memory. To store in the memory just press equals twice. - that's why there is no constant function. Alternatively key in (3)(=)(M) to store three. | |
| Memory store is not indicated you have to remember it. | |
| It is possible to store an overflow in the memory and later recover it by continual division by 10 | |
| Divide by zero shows "E000000" (no decimal point) and is recoverable by dividing by one | |
| 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 | |
| (EX) is used to exchange the display with the last stored result | |
| The (%) button divides by 100 so can be used to recover overflows |
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The scan on the left shows a typical early green line layout. The majority of components along the top are the voltage doubling circuitry for the VF display. |
