Calculators: Desktop: Sharp Compet CS-1109
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Size (approx): |
215mm x 240mm x 30-55mm
(keyboard),
115mm display (w,h,d) |
Power: |
Mains (240V 50Hz, 2.3W) power only through a permanently fixed mains cable of considerable length. | |
Display: | 10 digit green VFD plus a right symbol cluster for memory, negative and error indication. There are also upper commas for thousand indication. | |
Features: | Standard four functions with percentages, square root, count total, four function memory, register exchange, delete, double zero entry. Switches for constant, round/round up/round down. floating /fixed /accounting format, auto-accumulator. Semi-RPM Logic. | |
Age: | 1977 | |
Manufacturer: | Sharp Corporation, Made in Japan, serial No. 70005420. | |
Comments:
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A sturdy workman like calculator which is a bit a design jumble. Solid logic except for the input overflow and the divide to negative zero bug but useful range of functions. Very easy to read tilted display. |
Case and Design: | The two-piece case is made from smooth cream plastic whilst the top section is a mixture of matt and smooth black plastic. There is a very pronounced raised section at the back which tilts the green filtered display at 45 degrees. To the right of the display is a black and yellow printed metallic label that sits in its own recess. There is also another small metallic label printed "Made in Japan" to the far left below the display. |
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Keys and Switches: | The top most switch is for on/off. The next row consists of a constant switch (K), rounding options (up, 5/4, down), decimal point switch (F320A) and memory summation switch. The remaining keys are grouped in four banks; cancel keys, numeric keys (including 00), basic function keys and finally a group of "other functions" and memory control. The whole thing is a bit of a mess really. | |
Construction: | Remove the two screws from the bottom and the third from the top edge and the whole black front section will come off with a gentle pressure to pop the top and bottom lugs. |
Boards: | There is just one board (Sharp F1451CC A) that holds the key assemblies, switches and display unit. It sits loosely inside, not a screw in sight. Oddly enough the components are mounted on the underside. I imagine that this makes connection to the keys easier. The board is shaped to accommodate the mains transformer (top right) which is screwed down. | |
Components: | 1 x cpu: Hitachi
HD38401 7F 35, 36 pin DIL, 0.6" width 1 x 12 digit green VFD display: flat tube with left and right symbol clusters 1 x transistor 14 x diodes 8 x capacitors 4 x resistors 1 x mains transformer: P1417CC 24V7Z T 1 x voltage convertor: 1414 TDK Japan 2 x fuses in holders Minimum components - and most of them are
for the power supply regulation and VFD voltage. The IC is driving
the display direct. |
Logic comments: | (CE) is used once to cancel the last number entered and (C) to clear the whole calculator |
(CT) displays the count total, the number of numbers you have entered - useful for finding averages. | |
(->) deletes the last number entered but can also be used as a error recovery key | |
(00) allows more rapid number entry, especially in automatic decimal mode (A on the points switch) | |
Input overflow is not suppressed, keying an eleventh digit results in an overflow that is recoverable using (->) | |
Constant function is switched in with the "K" switch and operates on multiply and divide only | |
The rounding switch can select round up (^), round up/down (5/4) and round down (v) | |
The decimal point switch can be selected between floating "F", fixed "3,2,,0" and automatic financial mode "A" for $x.xx entry | |
Negative numbers are shown with a minus in the far right symbol cluster allowing full ten digit negative numbers | |
A summation switch "S" (sigma) adds the result of every calculation the memory | |
Divide by zero shows a "0." and "E" in the far right symbol cluster and is not recoverable | |
Overflow shows the result and "E" in the far right symbol cluster and is recoverable using (CE) or (->) | |
Memory storage is indicated by "M" in the far right symbol cluster | |
Overflow in memory flags an error (with "0.") and is not recoverable, but retains the original number | |
The register exchange key (^v) will also exchange the answer for the first number entered | |
Square roots of negative numbers are not allowed; it displays the result and error indicator and is recoverable using (CE) or (->) | |
It suffers the divide to negative zero (once) bug: key in (1)(+=)(2)(-=) to give "-1." now divide repeatedly by ten until you get "-0.", one more division will give you zero showing you the extra level of precision in the complimentary algorithm |
Footnotes: | Same case as the more advanced CS-2109. There was also a CD-1109A version that looks the same on the outside. |