Corvus 400

Date of introduction:  September, 1974 Display technology:  LED-stick
New price:  $39.95 Display size:  8
Size:  5.0" x 3.0" x 0.9"    
Weight:  3.7 ounces Serial No:  400-016025
Batteries:  4*N cells Date of manufacture:  mth 12 year 1974
AC-Adapter:  6V DC, 75mA Origin of manufacture:  USA
Precision:  8 Integrated circuits:  Mostek MK50280A
Memories:  1    
Program steps:   Courtesy of:  Peter Muckermann

Corvus_400_1_PCB.jpg (73217 Byte)The Corvus 400 uses four small N-sized batteries compared to the larger AA-sized cells of the Corvus 310 line. The result is a very small LED-type calculator similar to the Texas Instruments TI-1500. It uses a MK50280A single-chip calculator circuit and one digit driver circuits. Learn more about Mostek Calculator Integrated Circuits.

The Corvus 400 introduced the "N"-key known from desktop calculators. It instructs the calculator to display a count of entries made in a chain. This feature is used in obtaining averages. 

The later Corvus 400 got the MK50282A calculator circuit instead the MK50280. The differences are not yet discovered. Within some month the four unusual N-batteries were replaced with a standard 9V battery. Don't miss the Corvus 406.

The Corvus 400 was sold under the label of Radio Shack, don't miss the EC-230.

Other calculators sold under the Corvus brand are the 320, 415, 500, and 615 models. 

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If you have additions to the above article please email:

Joerg Woerner, October 17, 2002. No reprints without written permission.