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Casio fx-991MS (S-V.P.A.M.)

Casio fx-991MS
Image: Wikimedia CC BY-SA 3.0

The Casio fx-991MS is a scientific calculator with 12 digits precision and formula input logic. It has 401 functions, 50 keys, and an LCD (liquid crystal) display. The power source is Solar + LR44. The calculator was manufactured in China. Note: Older MS model still available in 2009

Facts at a glance:

FeatureValue
TypeScientific
Functions401
Keys50
Precision12
LogicFormula
Display typeLCD
Length154mm
Width77mm
Thickness12mm
Weight105g
Power Consumption0.000030W
Power SourceSolar + LR44
CountryChina
Year introduced2000

User Manual

You can download the Casio fx-991MS manual from this external link.

Diagnostics

Note that diagnostic tests generally delete any data on the calculator. Be sure to back up any important information held in the calculator before running these tests.

While holding SHIFT and 7 keys (or just SHIFT key for early models) press the ON key. Pressing the SHIFT key cycles through the 14 display test patterns. Press SHIFT one more time to change the display from 0 to 1 for the start of the keypad test - the numbers then increase as each key is pressed in the correct order (omitting the ON key which exits test mode).

Replacements:

If you have a Casio fx-991MS that is no longer working, you can consider replacing the calculator with a modern equivalent. We suggest the following current model as a replacement:

See other calculators by Casio