MASTFUYI Handheld Smart Digital Multimeter User Manual

1. Introduction

This manual provides essential information for the safe and effective operation of your MASTFUYI Handheld Smart Digital Multimeter. This instrument is a 5999 counts handheld digital intelligent multimeter designed for fast data measurement, featuring a large LCD double display and lighting for easy reading. It includes overload protection and a low battery indicator. It is an ideal multifunctional instrument for professionals, factories, schools, and home use, designed and produced according to the safety requirements of International Electrotechnical Safety Standard (IEC-61010).

Please read this manual thoroughly before use and keep it for future reference.

2. Safety Information

To ensure safe operation, always adhere to the following safety precautions:

• Always inspect the multimeter and test leads for any damage before use. Do not use if damaged.
• Do not apply more than the rated voltage, as marked on the multimeter, between the terminals or between any terminal and earth ground.
• Use caution when working with voltages above 30V AC RMS, 42V peak, or 60V DC. These voltages pose a shock hazard.
• Do not operate the multimeter in explosive gas, vapor, or dust environments.
• Ensure the test leads are properly seated in the correct input jacks for the measurement being performed.
• Disconnect the circuit power and discharge all high-voltage capacitors before measuring resistance, continuity, or diode.
• Replace the batteries when the low battery indicator appears to ensure accurate readings.
• Do not attempt to repair or modify the multimeter. Refer servicing to qualified personnel.

3. Package Contents

Upon opening your package, please verify that all items listed below are present and in good condition:

• 1 x Digital Multimeter (FY128, FY128C, or FY129C model)
• 1 x Pair of Test Leads (Red and Black)
• 1 x Thermocouple (Included with FY129C only)
• 1 x Cloth Bag
• 1 x User Manual (English)

Figure 3.1: Contents of the product package.

4. Product Overview

The MASTFUYI Digital Multimeter is a compact and intelligent device designed for various electrical measurements. It features a large LCD screen for clear readings and a robust design for durability.

Figure 4.1: Front panel and function overview of the FY129C model.

1. NCV (Non-Contact Voltage) indicator
2. Flashlight
3. LCD screen
4. NCV/LIVE key
5. Power on button
6. Data hold key
7. Flashlight button
8. Input jack (for test leads)
9. COM jack (common ground for test leads)

The device also includes a support bracket for convenient hands-free operation.

Figure 4.2: Multimeter with support bracket.

5. Specifications

The following table details the functional parameters for the FY128, FY128C, and FY129C models:

Figure 5.1: Detailed functional parameters for all models.

Figure 5.2: Visual representation of the functional parameters table.

Dimensions: 123 * 61 * 24mm (4.84 * 2.40 * 0.94in)

Figure 5.3: Multimeter dimensions.

6. Setup

6.1 Battery Installation

The multimeter requires two 1.5V AAA batteries (not included). To install:

1. Ensure the multimeter is powered off and disconnect any test leads.
2. Locate the battery compartment cover on the back of the device.
3. Use a screwdriver to open the battery compartment.
4. Insert two AAA batteries, observing the correct polarity (+ and -) as indicated inside the compartment.
5. Replace the battery compartment cover and secure it with the screw.

6.2 Connecting Test Leads

To perform measurements, connect the test leads as follows:

• Insert the black test lead into the 'COM' (common) jack.
• Insert the red test lead into the 'INPUT' jack for most voltage, resistance, frequency, capacitance, and diode measurements.
• For temperature measurements (FY129C only), connect the thermocouple to the designated input jacks, observing polarity if applicable.

Figure 6.1: Correct connection of test leads.

7. Operating Instructions

7.1 Power On/Off

Press the red power button (labeled with a circle and vertical line) to turn the multimeter on or off.

7.2 Measurement Modes

The multimeter supports two primary measurement modes:

• Auto Identification Mode: The multimeter automatically detects and measures AC/DC voltage, frequency, resistance, and continuity. This is the default mode for FY128 and FY128C.
• Manual Switching Mode: For FY129C, you can manually select specific functions like AC/DC voltage, frequency, resistance, continuity, diode, capacitance, and LIVE NCV. Use the 'SEL' button to cycle through these functions.

Figure 7.1: Auto identification vs. Manual switching modes.

7.3 Specific Measurement Functions (FY129C)

• AC/DC Voltage: Connect test leads to the circuit. The multimeter will automatically detect AC or DC voltage in auto mode. For manual mode, select the appropriate voltage function.
• Resistance: Ensure the circuit is de-energized. Connect test leads across the component to measure resistance.
• Frequency: Connect test leads to the signal source.
• Capacitance: Ensure the capacitor is discharged before measurement. Connect test leads across the capacitor terminals.
• Diode: Connect test leads across the diode. The display will show the forward voltage drop.
• Continuity: Connect test leads across the circuit. A beep indicates continuity.
• NCV (Non-Contact Voltage): Hold the multimeter near a live wire. The NCV indicator and audible alarm will activate if voltage is detected.
• Live Wire Checking: Use the red test lead to touch the live wire. The display will show 'LIVE' and an indication of live voltage.
• Temperature: Connect the thermocouple to the designated jacks. The FY129C can measure both ambient and probe temperature.

Figure 7.2: Automatic voltage measurement.

Figure 7.3: Capacitance measurement.

Figure 7.4: Temperature measurement.

Figure 7.5: Live wire checking.

Figure 7.6: NCV insulation safety.

7.4 Additional Functions

• Data Hold: Press the 'HOLD' button to freeze the current reading on the display. Press again to release.
• Flashlight: Press the flashlight button to turn on the built-in flashlight for illuminating dark work areas.
• Screen Backlight: The LCD screen has a backlight for improved visibility in low-light conditions.
• Auto Shutdown: The multimeter will automatically power off after a period of inactivity to conserve battery life.

8. Maintenance

8.1 Cleaning

Wipe the case with a damp cloth and mild detergent. Do not use abrasives or solvents. Keep the input terminals free from dirt and moisture.

8.2 Battery Replacement

When the low battery indicator appears on the display, replace the batteries as described in Section 6.1. Always use new 1.5V AAA batteries.

8.3 Storage

If the multimeter is not used for an extended period, remove the batteries to prevent leakage and damage to the device. Store in a cool, dry place away from direct sunlight.

9. Troubleshooting

• No display or faint display: Check battery installation and replace batteries if necessary.
• Incorrect readings: Ensure test leads are correctly connected and fully inserted. Verify the correct measurement function is selected (if applicable). Check battery level.
• No continuity beep: Ensure the circuit is powered off and the continuity function is selected.
• NCV not detecting: Ensure the NCV/LIVE button is pressed and the multimeter is held close enough to the live source.

10. User Tips

• Always start with the auto-identification mode for general checks, then switch to manual mode for specific measurements if needed (FY129C).
• Utilize the data hold function when taking measurements in hard-to-read locations.
• The built-in flashlight is very useful for working in dimly lit environments, enhancing safety and accuracy.
• For temperature measurements, ensure the thermocouple is securely connected and making good contact with the object being measured.

11. Warranty and Support

For warranty information, technical support, or service inquiries, please contact your original point of purchase or the manufacturer directly. Keep your purchase receipt as proof of purchase.