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Calculators: Desktop: Accuron 831
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Size (approx): |
113mm
x 180mm x 34mm (max)
(w,h,d) |
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Power: |
6V DC, 4 x C size batteries. It accepts an adaptor (undefined but 2.5mm plug centre positive) through socket on right side in line with the display. | ||
| Case: | The three-piece case has a black patterned base and white smooth centre piece and smooth black front. A narrow heavily tilted display filter gives a clean, bright display when sat in front of you on a desk. The front section has a small printed metal plate that sits in its own recess with the makers name. A larger brushed aluminium plate sits around the on/off switch and the constant function switch and is also printed black with the labels and model number. They keys are old fashioned square with raised circles like the larger earlier desktops. On my example the (CM) key has blue ink dripping down the side of the circle. They are long travel and very hollow sounding and a bit sticky. | ||
| Display: | 8 digit green VFD, ninth digit for minus and error flags. There is also a discrete red LED for memory indication. | ||
| Features: | Standard four functions, switch constant and three function memory | ||
| Age: | 1974 | ||
| Manufacturer: | No maker's marks, serial no. (inside battery compartment) 37163 | ||
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Comments:
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Early solid feeling calculator which archaic keys and some low quality features. My sample has not survived well mechanically, but cosmetically OK. You can just about see the word "memo" printed on the rear of the green display filter and the red LED barely shows through the green filter - useless! Logic is sound and I like the ability to recover the result from memory overflow. The original cover is brown soft plastic with a flip over top and front popper closing. It has the word "accuron" embossed on the front. |
| Components: | 1 x cpu: Texas TMS0132NC
C7412 (Week 12 of 1974) 24 pin DIL, 0.6" width 1 x IC: Nat Semi LM555CN 412 (same week code) 8 pin DIL 0.3" width (this is a timer circuit) 1 x nine digit single tube round faced VFD display 1 x discrete red LED 18 x transistors 8 x diodes 4 x capacitors 44 x resistors 1 x transformer: Fuji UT9005 made in Japan 4K-08 |
| Boards: | The keyboard assembly (made of a large metal frame) is fixed above the main cpu board (ref 831) by four large screws. |
| Construction: | Remove the two screws at the back concealed under the lower two rubber feet. Hinge the front off from the top being careful not to snap the two top lugs. |
| Logic comments: | There is no cancel entry function (C) is used to clear the whole calculator. The manual says that the key can be used for clear entry but it cannot. |
| There is switched constant on multiply and divide only | |
| Input overflow is suppressed, inputting a ninth digit is ignored | |
| Negative sign is shown in the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| Divide by zero shows zero and "C" in the far left (ninth) digit and is not recoverable | |
| Overflow is shown by the result and "C" (or "E" if negative) in the far left (ninth) digit and is not recoverable | |
| Memory store is indicated by the red LED which can only just be seen behind the green filter. | |
| The (CM) key recalls the memory and cancels it. | |
| You can store an overflow in memory which is indicated by a "n" in the far left (ninth) digit, all keys are disabled except (CM) which on the first press recovers the result with "C" in the far left (ninth) digit, and a second press to clear the calculator - clever! |
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Here's a shot with the front cover removed showing the keyboard holding down the main cpu board (underneath) with four screws. A heap of transistors and resistors sit under the display and the ICs sit under the keyboard assembly. A mystery to me is why did they use the useless red LED to the left of the display tube when they had a spare ninth digit for memory indication? |
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The manual to the left measures 90mm x 140mm and
is printed in two colour (green and black) throughout. It has six
printed fold-out pages with clear but brief examples and instructions.
I imagine this calculator cost quite a bit of money when released so this is
a poor manual for that level of goods.
Printed in Malaysia. Buy a .pdf manual for this calculator |
