Collection Item 

Fate Microcifra 4 & 10
Brand:  Fate (Fábrica Argentina de Telas Engomadas), a local manufacturer of tires for cars. 
Model:  Microcifra 4 (basic) & 10 "Científica" (Scientist). 
Origin:  Argentina. 
Introduction:  1975, 1976? 
Type:  Pocket size calculator with LED display. Both operates with 6 (Yes: 6!) AA bateries or AC power with 9v adapter. 
Functions:  Microcifra 4: 4Basic functions, percent, constant and memory with algebraic notation. Microcifra 10: 4Basic functions, trascendental functions and memory with RPN notation. 
Display:  One block of 8 red LED digit with 9 magnify glasses (leftmost digit not used!). 
Keyboard:  Both machines have 22 keys on flexible cooper switch plus On/Off switch with attractive colors and rare vertical layout. Also the Microcifra 4 has some explanations on the keys: "Ingresa cifra en Memoria" (Input number in memory), "Muestra cifra en memoria" (Show number in memory) and "Activa visor" (Resume display). The Microcifra 10 has a F key for a 2nd function in most keys. Please compare with the Microcifra 3 Dodge. 
Main chips:  Unknown, both machines are unopened, but Fate used Rockwell chips in other similar models. 
Logic comments:  Microcifra 4: Simple algebraic input, constant in the 4 functions with the k= key. Memory with limited functionality: Only "Ingresa cifra en Memoria" and "Muestra cifra en memoria", there is no M+ or M keys. A brief description of the keyboard: 0 to 9 and ,: Numerals and decimal point. Note: Latin american notation uses a comma "," instead of a point "." for decimals. However, the display shows a point, not a comma. +, , x, ÷: 4 basic functions. =: Equal key, completes a calculation. k=: Equal in constant mode. %: Percent. m with down arrow: "Ingresa cifra en Memoria", Memory input. m with up arrow and o: "Muestra cifra en memoria", Memory recall. c: Clear machine. v: "Visor" (display), resumes display after automatic display off. Microcifra 10: RPN notation with a 4level stack (X, Y, Z, T registers like the HP35), basic functions plus SIN/COS/TAN and inverses, LN/LOG, e^x, y^x, angle convertion, Square root, Reciprocal, Pi, exchange X and Y registers. There is no % key like the Microcifra 4! Memory with more functionality: Diamond M for Memory Display, Arrow M for Memory Input and +M and M keys for Memory Add and Subtract. The clear function is divided in two keys: C* for all clear and C to clear the last input or clear function if you previously press F. There is no scientific notation with exponent, so the range is limited to a maximum of 8 digits. A brief description of the keyboard: 0 to 9 and ,: Numerals and decimal point. Note: Latin american notation uses a comma "," instead of a point "." for decimals. However, the display shows a point, not a comma. +, , x, ÷: 4 basic functions. E: "Entrada" (input), the input key in RPN notation. C*: Clear machine. C: Clear last entry. V: "Visor" (display), resumes display after automatic display off. F: Function key, enables the 2nd. function of the most keys. Diamond M: Memory display. +/: Change sign. 2nd. functions: cos, sen, tg, arc cos, arc sen, arc tg: Trigonometric functions. log, ln, y^x, e^x, Square root, 1/x, Pi: Other functions. x<>y: Exchange X and Y registers. Right arrow M, +M, M: Input, add and subtract to the memory content. g>r, r>g: Converts between degrees and radians. cf: Clear function key. Both models: Negative numbers are represented with "" at the left of the first digit. The display uses only 8 digit, so you can display a negative number with a maximum of 7 digits. Overflow is indicated with all decimal points on and is recoverable, just press C to continue. There is no 0 bug, but both machines have the ghost decimal position bug: 2.25 + 3.75 gives 6.00, not simply 6. Automatic display off to preserve batteries, just press V to resume. 
Remarks:  Fate made differents pocketsize models with the same casing and keyboard design but with very differents colors and layouts: Model 3 (very basic), 4 (basic with memory), 6 (financial) and 10 (scientific). Curiously the model 4 has two variants: White body without memory and Black body with memory. In this page you can see the black body version, soon I'll post the white body version to compare. The Microcifra 10 is recognized as the world's second pocketsize calculator with RPN notation after the HP 35! I read about this but I want to confirm from other sources. Please write me if you have some information about this point. Please see the Microcifra 3 Dodge. 
Size:  5.71 x 2.56 x 1.18 in, 145 x 65 x 30 mm. 
Accesories:  Cardboard box, pouch and user manual for both calculators. Also I have the original warranty for the Microcifra 4 and the original AC adapter for the Microcifra 10. The 9v voltage adapter is the same for both calculators but the plug size is different (please see the pictures), so I can't use this adapter on the Microcifra 4! 
Condition:  (9/10) Mint, very good, full working. 