Corvus 525 a.k.a. CheckMaster

Date of introduction:  1975 Display technology:  LED-modules
New price:  $39.95 Display size:  6
Size:  3.8" x 2.1" x 0.13"
 94 x 172 x 25 mm3
Weight:  1.4 ounces, 151 grams Serial No:  525-0081597
Batteries:  6*AAA cells Date of manufacture:  mth 06 year 1975
AC-Adapter:   Origin of manufacture:  USA
Precision:  6 Integrated circuits:  Mostek MK6225N
Memories:  1    
Program steps:   Courtesy of:  Hans Bloemen

The Corvus 525 - better known as CheckMaster - looks different to electronic calculators. No doubt, you can't perform even basic calculations with this rare cuty ! The CheckMaster was introduced in 1975 and keeps track of your check book. The three dedicated keys


simply add to memory, subtract from memory and display the balance of the memory. 

CheckMaster_1.jpg (46313 Byte)When not in use the CheckMaster folds together to a stylish and slim unit that keeps the balance in memory even shut off. Due to high power consumption of the memory the CheckMaster is powered by 6 AAA-size batteries.

CheckMaster_PCB.jpg (51391 Byte)Dismantling the CheckMaster reveals a MK6225N custom programmed single-chip calculator circuit, a small 7-segment LED display and lot of space for the batteries. Learn more about Mostek Calculator Integrated Circuits.

About 7 years later, when the power conserving C-MOS electronics was introduced, a lot of calculators appeared with dedicated check book functions. Don't miss the TI-1880 Checkwriter, TI-2200, Canon Checkbook and some sibblings like the National Semiconductor NS-103 A, the Olivetti Chequebook and the Radio Shack EC-430.

Don't miss "real" calculators of the Corvus brand like the 310, 320, 400, 415, 500, and 615 models and the desktop line 300E, 305, and 307.

horizontal rule

If you have additions to the above article please email:

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