1. Introduzzjoni
The Brother HD-390D is a high-precision analog multimeter designed for electricians, hobbyists, and home maintenance tasks. It provides accurate measurements for AC/DC voltage, AC/DC current, resistance, and battery levels. This manual provides essential information for safe and effective operation of your device.
2. Informazzjoni dwar is-Sigurtà
WARNING: READ AND UNDERSTAND THIS MANUAL BEFORE USING THE INSTRUMENT. Failure to understand and comply with the WARNING and operating instructions can result in serious or fatal injuries and/or property damage.
- Always ensure the multimeter is set to the correct function and range before connecting to a circuit.
- Teċċedix il-klassifikazzjonijiet massimi tad-dħul għal kwalunkwe funzjoni.
- Use caution when working with live circuits. High voltagJista’ jkun perikoluż.
- Inspect test leads for damage before each use. Replace if insulation is cracked or wires are exposed.
- Kun żgur li l-għatu tal-batterija jkun magħluq sew qabel l-operazzjoni.
- For continued protection against fire, replace fuses only with specified types: 0.5A/250V and 10A/250V.
3. Kontenut tal-Pakkett
Ivverifika li l-oġġetti kollha huma preżenti fil-pakkett tiegħek:
- Brother HD-390D Analog Multimeter
- Wavel tat-Test (Aħmar u Iswed)
- Manwal tal-Istruzzjonijiet tal-Operatur
- Protective Carrying Case (may be included depending on variant)

Figure 3.1: Multimeter with test leads and optional carrying case.
Vidjo 3.1: Unboxing u r-reviżjoni inizjaliview of the Brother HD-390D Analog Multimeter.
4. Prodott Aktarview
The HD-390D features a clear analog display, a central rotary switch for function and range selection, and input jacks for test leads. An Ohm adjustment knob is provided for resistance measurements.

Figure 4.1: Front panel of the HD-390D Multimeter.
Komponenti Ewlenin:
- Display Analog: Large, easy-to-read scale for measurement readings.
- Swiċċ li jdur: Selects measurement function (Voltage, Current, Resistance, Battery) and range.
- Ġakkijiet tad-dħul: Connect test leads. 'COM' for common (black lead), 'VΩmA+' for positive (red lead) for most measurements, '+10A' for high current measurements.
- Ω ADJ Knob: Used to zero the meter for resistance measurements.
- Transistor/Diode Test Sockets: Dedicated sockets for testing transistors (NPN/PNP hFE) and diodes.
5. Setup
5.1 Installazzjoni tal-batterija
The multimeter requires two 1.5V AAA batteries and one 9V battery for operation. These are not included.
- Locate the battery cover on the back of the multimeter.
- Slide the cover down and open as indicated by the 'PULL DOWN' and 'OPEN' markings.
- Insert the two 1.5V AAA batteries and one 9V battery, observing correct polarity.
- Agħlaq l-għatu tal-batterija sew.

Figure 5.1: Back panel with battery and fuse access.
5.2 Konnessjoni tal-wajers tat-test
Always connect the test leads correctly for accurate and safe measurements.
- Insert the black test lead into the 'COM' (Common) jack.
- Għal ħafna kejl (Voltage, Resistance, low Current), insert the red test lead into the 'VΩmA+' jack.
- For high current measurements (up to 10A), insert the red test lead into the '+10A' jack.

Figure 5.2: Multimeter with test leads connected.
6. Istruzzjonijiet Operattivi
Before taking any measurement, ensure the test leads are properly connected and the rotary switch is set to the desired function and range.
6.1 DC Voltage Measurement (DC V)
- Connect the red lead to 'VΩmA+' and the black lead to 'COM'.
- Set the rotary switch to the desired DC V range (e.g., 0.1V, 0.5V, 2.5V, 10V, 50V, 250V, 1000V). Start with the highest range if the voltage mhux magħruf.
- Qabbad il-probi tat-test b'mod parallel mal-komponent jew iċ-ċirkwit li għandu jitkejjel.
- Aqra l-voltage value from the appropriate DC V scale on the analog display.
6.2 AC Voltage Measurement (AC V)
- Connect the red lead to 'VΩmA+' and the black lead to 'COM'.
- Set the rotary switch to the desired AC V range (e.g., 10V, 50V, 250V, 1000V). Start with the highest range if the voltage mhux magħruf.
- Qabbad il-probi tat-test b'mod parallel mal-komponent jew iċ-ċirkwit li għandu jitkejjel.
- Aqra l-voltage value from the appropriate AC V scale on the analog display.
6.3 DC Current Measurement (DC A)
- For currents up to 250mA, connect the red lead to 'VΩmA+' and the black lead to 'COM'. For currents up to 10A, connect the red lead to '+10A' and the black lead to 'COM'.
- Set the rotary switch to the desired DC A range (e.g., 0.05mA, 0.25mA, 2.5mA, 25mA, 250mA, 10A). Start with the highest range if the current is unknown.
- Importanti: Connect the multimeter in series with the circuit to be measured. Break the circuit and insert the meter.
- Read the current value from the appropriate DC A scale.
6.4 AC Current Measurement (AC A)
- For currents up to 250mA, connect the red lead to 'VΩmA+' and the black lead to 'COM'. For currents up to 10A, connect the red lead to '+10A' and the black lead to 'COM'.
- Set the rotary switch to the desired AC A range (e.g., 0.05mA, 0.25mA, 2.5mA, 25mA, 250mA, 10A). Start with the highest range if the current is unknown.
- Importanti: Connect the multimeter in series with the circuit to be measured. Break the circuit and insert the meter.
- Read the current value from the appropriate AC A scale.
6.5 Kejl tar-Reżistenza (Ω)
- Connect the red lead to 'VΩmA+' and the black lead to 'COM'.
- Set the rotary switch to the desired Resistance range (e.g., X1, X10, X1K, X10K, X100K).
- Aġġustament żero: Short the test leads together. While shorted, adjust the 'Ω ADJ' knob until the needle points to '0' on the Ohm scale. This must be done for each resistance range.
- Connect the test probes across the component to be measured (ensure the component is de-energized).
- Read the resistance value from the Ohm scale and multiply by the selected range multiplier.
6.6 Battery Test (BATT)
- Connect the red lead to 'VΩmA+' and the black lead to 'COM'.
- Set the rotary switch to the 'BATT' function (1.5V or 9V).
- Connect the test probes to the battery terminals, observing polarity.
- Aqra l-batterija voltage from the appropriate battery scale.
6.7 Diode and Transistor Check
- Set the rotary switch to the 'Ω X 10' range for transistor and diode checks.
- For transistor hFE measurement, insert the transistor leads into the appropriate NPN or PNP sockets.
- For diode check, use the extra jack as indicated in the specifications.
6.8 Kontroll tal-kontinwità
- Set the rotary switch to the 'Continuity Check' position (often indicated by a speaker icon).
- Qabbad il-probi tat-test madwar iċ-ċirkwit jew il-komponent.
- If the resistance is less than 200 Ohms, the beeper will sound, indicating continuity.
7. Speċifikazzjonijiet
The following table details the technical specifications of the Brother HD-390D Analog Multimeter:

Figura 7.1: DC VoltagSpeċifikazzjonijiet elettroniċi.

Figura 7.2: Vol ACtage, Current, Resistance, and other Specifications.
| Karatteristika | Speċifikazzjoni |
|---|---|
| AC Voltage Meded | 0.1V, 0.5V, 2.5V, 10V, 50V, 250V, 1000V |
| DC Voltage Meded | 0.1V, 0.5V, 2.5V, 10V, 50V, 250V, 1000V |
| Firxiet tal-Kurrent AC | 0.05mA, 0.25mA, 2.5mA, 25mA, 250mA, 10A |
| Firxiet tal-Kurrent DC | 0.05mA, 0.25mA, 2.5mA, 25mA, 250mA, 10A |
| Meded ta 'Reżistenza | X1 (0.2 ~ 2KΩ), X10 (2 ~ 20KΩ), X1K (200 ~ 2MΩ), X10K (2K ~ 20MΩ), X100K (20K ~ 200MΩ) |
| Test tal-batterija | 1.5V, 9V |
| Iċċekkja tat-transistor | hFE: 0-1000 (via extra jack, at Ω X 10 Range) |
| Iċċekkja tad-diode | IF, IR, LI, LV (at Ω X 10 Range) |
| Kontroll ta' Kontinwità | Beeper sounding (<200 Ohm) |
| Provvista tal-Enerġija | 2 x 1.5V AAA batteries, 1 x 9V battery |
| Modalità Operattiva | Firxa Manwali |
| Ċertifikazzjoni | CE |
| Standard Environmental Conditions | 23°C ± 5°C, humidity <75% RH |
| Working Environment Range | 0°C ~ 40°C, humidity <90% RH |
| Dimensjonijiet | 160mm x 105mm x 40mm |
8. Manutenzjoni
8.1 Tindif
Biex tnaddaf il-multimetru, imsaħ il-kaxxa b'adamp drapp u deterġent ħafif. Tużax abrażivi jew solventi. Kun żgur li l-apparat ikun mitfi u skonnettjat minn kwalunkwe ċirkwit qabel ma tnaddaf.
8.2 Sostituzzjoni tal-batterija
When the battery indicator shows low power, replace the batteries promptly to ensure accurate readings. Refer to Section 5.1 for battery installation instructions.
8.3 Sostituzzjoni tal-Fjus
Jekk il-funzjoni tal-kejl tal-kurrent tieqaf taħdem, il-fjus jista' jkun inħaraq. Biex tissostitwixxi l-fjus:
- Ensure the multimeter is powered off and disconnected from all circuits.
- Open the battery cover on the back of the unit (refer to Figure 5.1).
- Neħħi l-fjus(ijiet) il-qadim/qadima bir-reqqa.
- Replace with new fuses of the specified ratings: 0.5A/250V for mA ranges and 10A/250V for the 10A range.
- Agħlaq l-għatu tal-batterija sew.
9 Issolvi l-problemi
- No reading or unstable reading: Check battery levels and replace if necessary. Ensure test leads are securely connected and not damaged. Verify the rotary switch is set to the correct function and range.
- Incorrect resistance reading: Perform Ohm adjustment (zeroing) as described in Section 6.5. Ensure the component being tested is de-energized.
- Il-kejl tal-kurrent mhux qed jaħdem: Check the fuse(s) and replace if blown (refer to Section 8.3). Ensure the meter is connected in series with the circuit.
- Il-labra ma tiċċaqlaqx: Ensure the meter is powered on (if applicable for specific functions) and the test leads are making good contact.
10. Għajnuniet għall-Utenti
- Dejjem ibda bl-ogħla firxa: Meta tkejjel vol mhux magħruftage or current, always start with the highest range setting and then decrease it until you get a suitable reading. This prevents overloading the meter.
- Zero Ohm adjustment: Remember to perform the Ohm adjustment (zeroing) every time you change the resistance range for accurate readings.
- Observe polarity: For DC measurements, observing polarity is important. If the needle deflects backward, reverse the test leads.
- Analog vs. Digital: Analog multimeters are great for observing trends and fluctuating signals, as the needle movement can show changes more dynamically than a digital display.
11. Garanzija u Appoġġ
For warranty information or technical support, please refer to the documentation provided at the point of purchase or contact your vendor. Keep your purchase receipt as proof of purchase.





