1. Introduction
This manual provides detailed instructions for the OSALO OS-20TV Office Desktop Calculator. Designed for office, home, and school use, this portable calculator features a large 12-digit display, dual power supply (solar and battery), and a range of standard and advanced functions including tax calculation, memory functions, and grand total calculations.
Figure 1: OSALO OS-20TV Calculator Overview
2. Setup and Power Supply
The OS-20TV calculator operates using a dual power system: solar power and a single AA battery. For optimal performance and continuous use, it is recommended to install a battery.
2.1 Battery Installation
- Ensure the calculator is turned off.
- Locate the battery compartment cover on the back of the calculator.
- Slide or lift the cover to open the compartment.
- Insert one (1) AA battery, ensuring the correct polarity (+/-) as indicated inside the compartment.
- Replace the battery compartment cover securely.
The calculator will automatically switch to solar power in sufficient light conditions, conserving battery life.
3. Operating Instructions
Familiarize yourself with the calculator's key layout and functions for efficient operation.
Figure 2: Key Functions and Features
3.1 Basic Functions
- ON/AC (Power On/All Clear): Turns the calculator on and clears all entries and memory.
- C (Clear): Clears the last entry.
- +/- (Sign Change): Changes the sign of the displayed number (positive to negative, or vice versa).
- 0-9, . (Number Keys): Enters numerical values and decimal points.
- + (Addition), - (Subtraction), × (Multiplication), ÷ (Division): Performs basic arithmetic operations.
- = (Equals): Completes a calculation and displays the result.
- 00 (Double Zero): Enters two zeros simultaneously, useful for large numbers.
3.2 Advanced Functions
- % (Percent Key): Used for percentage calculations.
- To calculate a percentage of a number (e.g., 10% of 200): Enter 200 × 10 %.
- To add a percentage (e.g., 200 + 10%): Enter 200 + 10 %.
- To subtract a percentage (e.g., 200 - 10%): Enter 200 - 10 %.
- TAX+ (Tax Plus) / TAX- (Tax Minus): Used for tax calculations.
- To set the tax rate: Press RATE, enter the tax rate (e.g., 5 for 5%), then press RATE again.
- To add tax: Enter amount, then press TAX+.
- To subtract tax: Enter amount, then press TAX-.
- GT (Grand Total): Accumulates the results of all calculations performed since the last GT clear. Pressing GT displays the grand total. Pressing AC clears the grand total.
- M+ (Memory Plus): Adds the displayed number to the memory.
- M- (Memory Minus): Subtracts the displayed number from the memory.
- MRC (Memory Recall/Clear):
- Press once to recall the value stored in memory.
- Press twice to clear the memory.
- RECALL: Recalls the last entered number or result.
3.3 Decimal and Rounding Switches
The calculator features two slide switches located above the number pad to control decimal places and rounding behavior.
| Switch | Settings | Description |
|---|---|---|
| Decimal Selector | F, 4, 2, 0, ADD |
|
| Rounding Selector | ↑, 5/4, ↓ |
|
4. Maintenance
4.1 Cleaning
To maintain the calculator's appearance and functionality:
- Wipe the calculator with a soft, dry cloth.
- For stubborn dirt, slightly dampen the cloth with water or a mild, non-abrasive cleaner.
- Do not use strong solvents, alcohol, or abrasive cleaners, as these can damage the casing or display.
- Avoid getting moisture into the calculator's openings.
Figure 3: Durable Plastic Keys and Rubber Feet
4.2 Battery Replacement
If the display becomes dim or unresponsive in low light conditions, the AA battery may need replacement. Follow the battery installation steps in Section 2.1.
5. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Display is blank or dim. | Insufficient light for solar power, or dead/low battery. | Move to a brighter area or replace the AA battery. |
| Calculator does not respond to key presses. | Battery issue or temporary malfunction. | Replace the battery. Press the ON/AC button to reset the calculator. |
| Incorrect decimal places or rounding. | Decimal or rounding switches are set incorrectly. | Adjust the Decimal Selector and Rounding Selector switches to the desired settings (refer to Section 3.3). |
| Memory (M) indicator is on, but I don't need it. | A value is stored in memory. | Press MRC twice to clear the memory. |
6. Specifications
| Feature | Detail |
|---|---|
| Model Number | OS-20TV |
| Brand Name | OSALO |
| Max. Digits | 12 |
| Power Source | Dual Power Supply (Solar & 1 x AA Battery) |
| Battery Included | No |
| Material | ABS Plastic, Metal Panel |
| Style | Desktop/Portable |
| Dimensions (L x W x H) | 169mm x 105mm x 20mm |
| Weight | Approx. 0.19 kg |
| Certification | CE |
Figure 4: Product Dimensions
7. User Tips
Based on common usage patterns and feedback:
- For prolonged use in dimly lit environments, always ensure a fresh AA battery is installed.
- Utilize the "00" key for faster entry of large monetary values.
- Experiment with the decimal and rounding switches (F, 4, 2, 0, ADD and ↑, 5/4, ↓) to find the best setting for your specific accounting or calculation needs.
- The tilted display is designed for ergonomic viewing on a desktop.
8. Warranty and Support
For any issues, questions, or support regarding your OSALO OS-20TV calculator, please contact the seller or manufacturer directly. Keep your purchase receipt as proof of purchase for warranty claims.
