Casio FX-991MS 2nd Gen Scientific Calculator User Manual

1. Introduction

The Casio FX-991MS 2nd Gen is a non-programmable scientific calculator designed for a wide range of mathematical and scientific applications. It features 401 functions and a clear 2-line display, making it suitable for students and professionals. This manual provides essential information for setup, operation, maintenance, and troubleshooting.

Figure 1: Casio FX-991MS 2nd Gen Scientific Calculator.

1.1 Key Features

• 401 Built-in Functions
• 2-Line Display for enhanced readability
• Solar and Battery Dual Power Source
• Multi-Replay Function for formula recall and editing
• Durable, drop-resistant body with water-resistant printing on keys
• Color-coded keys for intuitive operation

1.2 What's in the Box

• 1 x Casio FX-991MS 2nd Gen Scientific Calculator
• 1 x User Manual (this document)
• 1 x Warranty Card with Serial Number
• 1 x Warranty Term Sheet

2. Setup

The Casio FX-991MS 2nd Gen calculator is designed for immediate use upon unboxing. It operates on both solar power and a nonstandard battery, ensuring continuous functionality.

2.1 Power Source

The calculator utilizes a dual power system: solar power for sufficient light conditions and a built-in nonstandard battery for low-light environments or when solar power is insufficient. No initial battery installation is required as the battery is pre-installed.

2.2 Turning On/Off

• To turn on: Press the ON button.
• To turn off: Press SHIFT then AC (OFF).

3. Operating Instructions

The Casio FX-991MS 2nd Gen offers a wide array of functions accessible through its intuitive key layout and 2-line display. The upper line displays the input expression, and the lower line shows the calculation result.

Figure 2: Calculator with its protective hard case.

3.1 Basic Calculations

Enter numbers and operators in sequence. Press = to obtain the result.

• Addition/Subtraction: Use + and - keys.
• Multiplication/Division: Use × and ÷ keys.
• Parentheses: Use ( and ) for grouping expressions.

3.2 Scientific Functions

Access scientific functions using the dedicated keys or by pressing SHIFT followed by the desired function key.

• Trigonometric Functions: sin, cos, tan and their inverse functions (SHIFT + sin, etc.).
• Logarithmic Functions: log (base 10) and ln (natural logarithm).
• Power and Root Functions: x², x³, √, ³√, xʸ.

Figure 3: Illustration of trigonometric function keys.

3.3 Statistical Calculations

The calculator supports various statistical calculations. To enter STAT mode, press MODE and select the appropriate statistical mode (e.g., SD for standard deviation, REG for regression).

• Data Entry: Input data points using the M+ key.
• Statistical Results: Calculate mean, standard deviation, sum of squares, etc., after data entry.

Figure 4: Illustration of statistical function keys.

3.4 Multi-Replay Function

The Multi-Replay function allows you to recall and edit previously executed formulas. Use the ▲ and ▼ cursor keys to navigate through past calculations. This feature is useful for correcting errors or performing similar calculations with different values.

Figure 5: The Multi-Replay function allows quick recall and editing of previous calculations.

3.5 Constants and Conversions

The calculator includes built-in scientific constants and unit conversion functions. Refer to the detailed function guide for specific constant codes and conversion procedures.

4. Maintenance

Proper maintenance ensures the longevity and optimal performance of your calculator.

4.1 Cleaning

Wipe the calculator's exterior with a soft, dry cloth. Avoid using abrasive cleaners, solvents, or harsh chemicals, as these can damage the casing and water-resistant key printing.

4.2 Storage

Store the calculator in a cool, dry place away from direct sunlight and extreme temperatures. Use the provided protective cover to prevent scratches and damage to the keys and display.

Figure 6: Dimensions of the Casio FX-991MS 2nd Gen Calculator (16.2L x 7.7W Centimeters).

5. Troubleshooting

If you encounter issues with your calculator, refer to the following common problems and solutions.

5.1 Display Issues

• Blank Display: Ensure sufficient light for solar power or that the battery is functional. If the display remains blank, try pressing the ON button.
• Faint Display: The battery may be low. While the calculator uses solar power, a weak battery can affect display clarity in certain conditions.

5.2 Incorrect Results

• Check Mode: Verify that the calculator is in the correct mode (e.g., COMP for general calculations, STAT for statistics). Press MODE to change.
• Angle Unit: Ensure the correct angle unit (DEG, RAD, GRA) is selected for trigonometric calculations. Press MODE multiple times to cycle through options.
• Reset: If issues persist, perform a full reset. Press SHIFT then CLR (MODE) and select All. This will clear all memory and settings.

6. Specifications

7. Warranty and Support

Your Casio FX-991MS 2nd Gen Scientific Calculator comes with a manufacturer's warranty and dedicated support.

7.1 Manufacturer Warranty

The product is covered by a 3-year All India Manufacturer Warranty from the date of purchase. An additional 6 months warranty can be availed by registering your product online.

• To avail warranty: Produce the original bill copy/invoice at an authorized Casio service center. The warranty card and stamp are not mandatory for online purchases.
• Online Registration: Register your product at https://register.casio.in for an extended warranty.

7.2 Customer Support

For any service-related inquiries or feedback, please contact Casio India:

• Helpline Number: 011-66999200
• Email: casiocare@casio.co.in
• Manufacturer Contact Information: Casio India Co Pvt Ltd, A-41, 1st Floor, MCIE, Mathura Road, New Delhi-110044