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Calculators: Handheld: Federal Compact
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| Size (approx): |
75mm
x 130mm x 20mm (w,h,d) Weight 108g excluding batteries |
| Power: | 3.0V, 2 x AA size batteries. It accepts an adapter (3V DC, 100mA, 3.5mm plug centre positive, 0.2W) through a socket on the top side to the far right. |
| Case: | Slab shaped calculator made from a two-piece black matt plastic case. The top and bottom end panels have a square ridged design. An oversized, wrap around green plastic display filter is flat and flush and gives a clean bright image. Below the display is a ridged area with a small recess for a black printed metallic sticker bearing the brand and model name. A large wrap around brushed aluminium panel surrounds the keyboard and has black printed text for the on /off switch label. The keys are short travel, squishy and in my example work well. |
| Display: | 8 digit green VFD, with a ninth digit for minus and error indication. |
| Features: | 4 function calculator with percentages and square roots |
| Age: | 1976 |
| Manufacturer: | Made in Japan, serial number 8695506 |
| Comments: | Cheap and cheerful calculator which is not any more compact that the other models in its range. The logic is OK apart from the pseudo fixed decimal and trailing zeros bugs. The original cover is think black plastic with open top and half-moon cut-outs. I know of at least two other models from Federal that used the same case (The Federal Student and Federal Memory). |
| Components: | 1 x cpu; Sharp LI2006 6A2 023
(date code January 1976) , 28 pin DIL, 0.6" width 1 x 9 digit VFD; single round faced tube: Itron DP95M, Japan 1 x transistor 5 x diodes 7 x capacitors 10 x resistors 2 x resistor arrays 1 x transformer |
| Boards: | The keyboard assembly (171-4Y-810R) (GICO 51.5.10 L32) (date code 10 May 1976) sits on top of the main cpu board (Y-810)and is connected by 16-way ribbon cable. This main board also sits lose in the case. |
| Construction: | Very difficult to open as it is held together by internal lugs only and the sides are so stiff that you cannot pop them easily at all. Be warned damage may result so don't bother! The easiest way I found was to lever the bottom edge off just enough to pop the lower side lug by squeezing in the rear section. Eventually the front will left off. Do not be tempted to pop the lugs you see inside the battery compartment as they are just attaching the display filter to the front section. |
| Logic comments: | The (CE) button is used to clear last entry of a number and the (C) clear the whole calculator. |
| Overflow on number input is suppressed as inputting a ninth digit is ignored | |
| An overflow shows the result with a “C” (or “E” if negative) in the far left (ninth) digit and is not recoverable | |
| Divide by zero results in zero and a "C” in the far left (ninth) digit and is not recoverable | |
| There is automatic constant on multiply and divide only | |
| Negative square roots are not allowed. The result is a zero with a “C” in the far left (ninth) digit and is not recoverable | |
| Negative numbers are shown by a "-" in the far left (ninth) digit thereby allowing full eight digit negative numbers. | |
| It suffers the pseudo fixed decimal bug: key in (1)(+)(0)(.)(0)(0)(0)(=) to give “1.000” which remains a three digit fixed decimal number until more digits are needed | |
| It suffers the trailing zeros square root bug: key in (1)(.)(0)(SQRT) and you get “1.0000000” as the answer |
