1. Introduction
Thank you for choosing the CEM DT-663H / DT-660B Handheld Digital Multimeter. This device is a high-precision, multifunctional electrical meter designed for a wide range of applications including electronic repair, HVAC, electrical engineering, environmental monitoring, quality inspection, and scientific research/education. The DT-663H model features True RMS measurement, 4000 counts display, and 0.5% high precision, along with advanced functions like capacitance, frequency, K-type temperature, and battery testing.
This manual provides essential information for the safe and effective use of your multimeter. Please read it thoroughly before operation and keep it for future reference.
2. Safety Information
Always observe safety precautions when using any electrical testing equipment. Failure to do so may result in injury or damage to the meter or equipment under test.
- Ensure the meter is in good working condition before use.
- Do not apply more than the rated voltage, as marked on the meter, 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.
- Always disconnect the test leads from the circuit before changing functions or ranges.
- Do not operate the meter with the case open or if the battery cover is not securely closed.
- Replace the battery as soon as the low battery indicator appears to ensure accurate readings.
- The meter features smart anti-burn and overload protection. However, always select the appropriate function and range to prevent damage.
3. Product Overview
The CEM DT-663H / DT-660B is a compact and robust digital multimeter designed for precision and ease of use. It features a large backlit LCD display for clear readings in various lighting conditions and a durable protective casing for enhanced shock resistance.
3.1. Key Features
- True RMS Measurement (DT-663H): Provides accurate readings for non-sinusoidal waveforms.
- 4000 Counts Display (DT-663H): Offers higher resolution for precise measurements.
- Auto-ranging: Automatically selects the correct measurement range.
- Backlit LCD Display: Ensures readability in dimly lit environments.
- Overload Protection: Safeguards the meter against damage from excessive input.
- Data Hold (HOLD): Freezes the current reading on the display.
- MAX/MIN Function: Records maximum and minimum values during a measurement session.
- Multifunction Rotary Switch: Intuitive selection of measurement modes.
- Durable Design: Protective rubber sleeve for shock resistance.
3.2. Meter Components
- LCD Display: Shows measurement readings, units, and function indicators.
- RANGE Button: Manually selects measurement range (disables auto-ranging).
- MODE Button: Toggles between different functions within a single rotary switch position (e.g., AC/DC voltage, diode/continuity).
- Rotary Function Switch: Selects the primary measurement function.
- 10A Input Jack: For high current measurements (up to 10A).
- MAX/MIN Button: Toggles between maximum, minimum, and current readings.
- HOLD/Backlight Button: Freezes the display reading; long press activates/deactivates backlight.
- V, Ω, Hz, CAP, Diode, Continuity, mA, uA Input Jack: For voltage, resistance, frequency, capacitance, diode, continuity, and low current measurements.
- COM Input Jack: Common (negative) input for all measurements.
4. Setup
4.1. Battery Installation
The multimeter requires batteries for operation (batteries are not included). To install or replace batteries:
- Ensure the multimeter is turned OFF and disconnect all test leads.
- Locate the battery compartment cover on the back of the meter.
- Unscrew the retaining screw(s) and remove the cover.
- Insert the correct type and number of batteries, observing polarity markings.
- Replace the battery cover and secure it with the screw(s).
4.2. Connecting Test Leads
Always connect the test leads correctly for accurate and safe measurements.
- Insert the black test lead into the COM (Common) input jack.
- For most measurements (voltage, resistance, continuity, diode, capacitance, frequency, mA/uA current), insert the red test lead into the V, Ω, Hz, CAP, Diode, Continuity, mA, uA input jack.
- For high current measurements (up to 10A), insert the red test lead into the 10A input jack.
5. Operating Instructions
Before taking any measurement, ensure the test leads are correctly connected and the rotary switch is set to the desired function.
5.1. Basic Measurements
- AC/DC Voltage Measurement:
Set the rotary switch to V~ (AC Voltage) or V- (DC Voltage). Connect the test leads in parallel to the circuit or component. The DT-663H model provides True RMS for AC voltage.
- Resistance Measurement:
Set the rotary switch to Ω. Ensure the circuit is de-energized. Connect the test leads across the component to measure its resistance.
- Continuity Test:
Set the rotary switch to the continuity symbol (usually shared with diode/resistance). Touch the test leads to the two points of the circuit. A continuous beep indicates a complete circuit. - Diode Test:
Set the rotary switch to the diode symbol (usually shared with continuity/resistance). Connect the red lead to the anode and the black lead to the cathode of the diode. The display will show the forward voltage drop. Reverse the leads to check for open circuit. - AC/DC Current Measurement (DT-663H):
Set the rotary switch to A~ (AC Current) or A- (DC Current) or mA/uA. Connect the meter in series with the circuit. Use the 10A jack for high currents and the V, Ω, Hz, CAP, Diode, Continuity, mA, uA jack for low currents. - Capacitance Measurement (DT-663H):
Set the rotary switch to CAP. Ensure the capacitor is discharged before connecting the test leads. - Frequency Measurement (DT-663H):
Set the rotary switch to Hz%. Connect the test leads to the signal source. - Temperature Measurement (DT-663H):
Set the rotary switch to °C/°F. Connect the K-type thermocouple probe to the appropriate input jacks (usually marked with temperature symbols).
- Battery Test (DT-663H):
Set the rotary switch to the battery symbol. Connect the test leads to the battery terminals to check its voltage under a small load.
5.2. Special Functions
- MODE Button: Press to switch between AC/DC voltage, diode/continuity, or other sub-functions available at a single rotary switch position.
- RANGE Button: In auto-ranging mode, press to switch to manual ranging. Subsequent presses cycle through available ranges. Long press to return to auto-ranging.
- HOLD Button: Press briefly to freeze the current reading on the display. Press again to release.
- Backlight: Long press the HOLD button to turn the LCD backlight ON or OFF.
- MAX/MIN Button: Press to cycle through maximum, minimum, and current readings captured since the function was activated.
6. Maintenance
Proper maintenance ensures the longevity and accuracy of your multimeter.
6.1. 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.
6.2. Battery Replacement
When the low battery indicator appears on the display, replace the batteries immediately to maintain measurement accuracy. Refer to section 4.1 for battery installation instructions.
6.3. Test Lead Inspection
Regularly inspect the test leads for any signs of damage, such as cracked insulation or exposed metal. Replace damaged leads immediately to prevent electrical shock hazards.
6.4. Storage
If the meter is not to be used for an extended period, remove the batteries to prevent leakage and damage to the device. Store the meter in a cool, dry place.
7. Troubleshooting
If you encounter issues with your multimeter, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No display or dim display | Dead or low batteries; Incorrect battery installation | Replace batteries; Check battery polarity. |
| Incorrect readings | Wrong function/range selected; Damaged test leads; External interference | Select correct function/range; Inspect and replace test leads; Move away from strong electromagnetic fields. |
| "OL" or "OVER" displayed | Overload (input exceeds selected range) | Select a higher range or ensure input is within meter's specifications. |
| Meter does not respond | Meter frozen; Internal fault | Turn off and on again; Remove and reinsert batteries. If problem persists, contact support. |
8. Specifications
| Feature | Specification |
|---|---|
| Brand | CEM |
| Models | DT-663H, DT-660B |
| DIY Supplies | Electrical |
| Origin | Mainland China |
| Display Counts | 4000 (DT-663H) |
| Precision | 0.5% (DT-663H) |
| True RMS | Yes (DT-663H) |
| Auto-ranging | Yes |
| Backlight | Yes |
| Overload Protection | Yes |
| Functions (DT-663H) | AC/DC Voltage, AC/DC Current, Resistance, Capacitance, Frequency, K-type Temperature, Diode Test, Continuity Test, Battery Test, Data Hold, MAX/MIN |
| Functions (DT-660B) | AC/DC Voltage, Resistance, Diode Test, Continuity Test, Data Hold, MAX/MIN |
| Package Dimensions (approx.) | 30cm (L) x 15cm (W) x 15cm (H) |
| Package Weight (approx.) | 0.39 kg |
9. User Tips
- Always Start with the Highest Range: When measuring an unknown voltage or current, start with the highest range setting and work your way down to avoid overloading the meter.
- Check Test Leads: Before each use, perform a quick continuity test on your test leads by touching the tips together. This ensures they are not broken internally.
- De-energize Circuits for Resistance/Continuity: Always ensure the circuit or component is completely de-energized before measuring resistance or continuity to prevent damage to the meter.
- Use Data Hold for Unstable Readings: If readings are fluctuating, use the HOLD function to capture a stable value for easier recording.
- Mind the Input Jacks: Double-check that your test leads are in the correct input jacks (e.g., 10A for high current, VΩmA for most other functions) before making a measurement.
10. Warranty and Support
For technical support, service, or warranty inquiries, please contact the seller or manufacturer directly. Keep your purchase receipt as proof of purchase.
While specific warranty details are not provided in this manual, general support for product issues is typically available. For any issues with the product, such as damage or non-delivery, please reach out to the point of purchase for assistance.
