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2002TON
1980
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1988

Singer Friden 1200

Brief History
Well-known sewing machine manufacturer, The Singer Corporation established in 1851, due to declining home sewing, they decided to enter new markets, so Singer purchased a calculator manufacturer, Friden Inc. in 1965. The new management saw that they could not compete with japanese manufacturers in long term, so an arrangement between Singer and Hitachi was established to develop and distribute electronic calculators. So Hitachi’s products were sold in the US and Europe under the well-known Friden and Singer brands. Later, more arrangements were concluded with other, mostly japanese calculator manufacturers. Hitachi developed the KK 221B calculator in 1973, which was distributed under the name Singer—Friden 1200 too. It has unique calculating capabilities: the machine has an internal precision of 12 digits (of which 7 can be decimal), but the display capacity is only 8 digits and computes with fixed decimal point. The important ICs were produced by Hitachi, the VFD tube is from Futaba, all internal components are japanese made.
Manufacturer:The Singer Company (USA)
OEM:Hitachi Ltd. (Japan)
OEM model:KK 221B
Mfg. date:1973
Size:11,3×16,8×4 cm
Weight (ready for operate):n.a.
Type:four-function
Capacity:12 digits (input)
8 (12) digits (display)
12 digits (internal precision)
Operating logic:arithmetic
CPU:Hitachi HD3576
Registers:2 standard (with saving the pending operation)
1 constant (with saving the pending operation)
1 memory (with arithmetic and auto-summation)
Features:%calculation with percent Fixfixed-point notation: the listed decimals can be chosen (0-7)
Display:8+1 digit VFD (Futaba 9-CT-01)
Power:battery pack or adaptor

Singer Friden 1200 (only the last 8 digit can be seen on the display of the 12 entered digits)

Inside of the 1200: main PCB on the left, keyboard on the right

Keyboard of the 1200
Detailed description
At power on, the machine calculates with 0 decimal places. All results obtained with += and -= key will be rounded to the specified decimal places. To set the decimal places, place the left switch to leftmost position (DS = Decimal Selection) and press the appropriate number key (0-7). Entering greater number than 7 will result in 7 decimal places. All other keys will be ignored. To calculate without summarizing to memory, the left switch must be in the center position. The numbers keyed in can be other format than the decimal setting, the calculator will automatically rounds the results if needed. Up to 12 digits can be entered, of which 7 can be fractional. Displaying results are unusual if the number exceeded the 8 digit capacity. The first display shows only the leftmost places, and the second shows the 8 lower significant digits. To switch to the second display and vice versa, press the key. Example: (DS 6 setting) 125.55201235 × 15 += 1143.45 += results 3026.730185. The display shows 30 (without decimal point), after pressing the the display changes to 26.730185. The constant switch can be operated as with other calculators used arithmetic logic, so the first keyed number will be the constant for further multiplications or divisions. If the result overflows (if the integer part exceeds 12 digits), a small circle appears in the right of the display. To clear the error sign, press the C key. If the result can not be displayed with the specified decimal digits due to long integer part, the calculator automatically decreased the number of decimal places. If the left switch is in the rightmost setting (∑), the memory automatically accumulates results obtained by pressing the += and -= keys. If the memory contains any value other than 0, an M sign is appears on the right of the display. Pressing T1 shows the contents of the memory, and clears it.
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