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Calculators: Handheld: Brother 827R
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Size (approx): | 78mm x
127mm x 17-22mm (w,h,d) Weight 150g excluding batteries |
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Power: |
4.5V DC, 3 x (almost) AA size batteries. I cannot get AAs to fit so I think this may have used a special rechargeable battery pack. Does accept an adapter (undefined but 4mm plug, centre negative) through socket on the top side at the far right. A label in the battery compartment states "Only Rechargeable Battery 4 x 1.2V". The battery compartment has a small block of foam to stop you putting in four batteries. | |
| Case: | The case is two piece cream (originally white?) smooth plastic with the lower section having prominent grip-ridges on the sides. An oversized, wrap around red display filter gives a clear enough display even though the digits are quite small. Keys are loose, squishy and bouncy like the Commodore's but work very well. A small printed a brushed aluminium panel holds the name and model number and sits in an inset recess. Quite block-shaped but nevertheless nice to hold. There are two switches, one for on/off and one for memory summation (sigma) with raised labels that might have been highlighted but now worn away. | |
| Display: | 8 digit bubble lens red LED ninth digit for negative sign. An additional isolated LED pin-point is used to indicate memory usage. | |
| Features: | Standard four functions with percentages and four function memory. Switch for memory summation. | |
| Age: | 1974 | |
| Manufacturer: | Brother International Corp, made in Hong Kong. Serial No. 4445596. | |
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Comments:
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Nice brick-shaped calculator with mostly sound logic. Original black plastic case has top flap with popper closing and gold printed Brother logo. Battery type appears a bit odd as I cannot fit the three AAs it looks like it should take. |
| Components: | 1 x cpu: Texas TMS 0603NC B 7437
(date code week 37 1974) 28 pin DIL 2 x Texas SN75494 7346 (display driver?) 16 pin DIL chip 1 x 9 digit bubble lens LED display 2 x transistors 5 x diodes 6 x capacitors 0 x resistor arrays 11 x resistors 1 x transformer |
| Boards: | The keyboard board (GICO 49.10.14) is secured to the keyboard by six screws and to the main board by 17 strong bare wires. |
| Construction: | Loosen the two screws on the back (you do not have to fully remove them and hinge up the back at the top. the front then lifts off easily. Watch out for the very small plastic strip that holds over the display filter as it can be very easily broken. |
| Logic comments: | The (C) key operates as a cancel entry function on the first press and all clear on the second |
| Input overflow is suppressed, inputting a ninth digit is ignored | |
| Negative numbers are shown with a "-" in the ninth (far left) digit thereby allowing eight digit negative numbers. | |
| There is automatic constant on all four functions | |
| Divide by zero shows a "C" in the ninth (far left) digit and is not recoverable | |
| Overflow displays the result and "C" (or "E" for negative overflows) in the ninth (far left) digit and is not recoverable | |
| The memory is indicated by a far right point LED | |
| Memory overflow is indicated by an upper "n" in the ninth (far left) digit and is not recoverable (the error state stays even when you cancel and carry on doing other calculations). | |
| The percentage function divides the current register by 100. | |
| There is a switch to change the memory into summation (sigma) mode. Every answer accumulates into the memory. |
