Corvus 305

Date of introduction:  1973 Display technology:  Panaplex II
New price:   Display size:  10
Size:  8.5" x 6.5" x 2.2"    
Weight:  1 pound 9 ounces Serial No:  305-103660
Batteries:   Date of manufacture:  mth 08 year 1973
AC-Adapter:  115 V Origin of manufacture:  USA
Precision:  10 Integrated circuits:  Mostek MK6092P (7335) MK5017
Program steps:   Courtesy of:  Joerg Woerner

Corvus, the consumer division of the famous IC manufacturer MOSTEK, introduced with the Model 300E their first desktop four-function calculator. This unique Model 305 added a clock with calendar function, we know a similar approach from the Texas Instruments TI-3510 and the Garrett 2002.

Corvus_305_PCB.jpg (60605 Byte)Dismantling the calculator reveals a small surprise. The printed circuit board (PCB) is identical with the Corvus 300E and an additional clock module is located piggy back on the main board. 
Learn more about Mostek Calculator Integrated Circuits.

Corvus_305_Label.jpg (63740 Byte)The back side of the calculator gives immediately an explanation of the two mystery holes and the small slit noticed already in the PCB of the Corvus 300E. They occupy the push buttons to adjust the clock and calendar plus a selector switch.

A small switch located near the [=] key selects between the calculator and clock mode:

Corvus_305_1.jpg (16948 Byte)CAL-Position  Normal calculator function known from the 300E.

Corvus_305_2.jpg (13859 Byte)CLK-Position  Reads the time in hours, minutes and seconds.

Corvus_305_3.jpg (11777 Byte)Every 10 seconds  Reads the date in month and day for 3 seconds.

Three different desktop calculators were available from Corvus:

Model 300E: Unusual desktop calculator with square-root function
Model 305: Added full clock function to the 300E
Model 307: Added 4-key memory instead the square-root function

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If you have additions to the above article please email:

Joerg Woerner, March 23, 2003. No reprints without written permission.