UNI-T UT33B, UT33C, UT33D Operating Manual

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Title

Overview
Unpacking Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The Meter structure
Functional Buttons
Measurement Operation

A. DC Voltage Measurement
B. AC Voltage Measurement
C. DC Current Measurement
D. Measuring Resistance
E. Diodes and Continuity

Measurement

F. Temperature Measurement

G. Battery Test

Table of Contents (1)

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Model UT33B/C/D: OPERATING MANUAL

Table of Contents (2)

Title

H. Square Wave Output
General Specifications
Accuracy Specifications

A. DC Voltage
B. AC Current
C. DC Current
D. Resistance
E. Diodes and Continuity

Measurement

F. Temperature
G. Battery Test
H. Square Wave Output
Maintenance
A. General Service
B. Replacing the Battery
C. Replacing the Fuses

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Model UT33B/C/D: OPERATING MANUAL

Overview

This Operating Manual covers information on safety and cautions. Please read
the relevant information carefully and observe all the Warnings and Notes strictly.

Warning
To avoid electric shock or personal injury , read the “Safety Information” and
“Rules for Safety Operation” carefully before using the Meter.

The Model UT33B, UT33C and UT33D Multimeters (hereafter referred as “the
Meter”) are 3 1/2 digits with steady operations, fashionable design and highly
reliable hand-held measuring instrument. The Meter can measure AC/DC voltage,
AC/DC Current, Resistance, Temperature, Diode and Continuity. It is an ideal
tool for maintenance.
Except where noted, the descriptions and instructions in this Operating Manual
apply to all Model UT33B/UT33C/UT33D.

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Model UT33B/C/D: OPERATING MANUAL

Open the package case and take out the Meter. Check the following items carefully
to see any missing or damaged part:

In the event you find any missing or damage, please contact your dealer immediately .

Unpacking Inspection

Item

1
2
3
4

Description

Qty

1 piece

1 pair
1 piece
1 piece

English Operating Manual
Test Lead
Point Contact Temperature Probe (UT33C only)
Holster

4

Model UT33B/C/D: OPERATING MANUAL

Safety Information(1)

Safety Information

This Meter complies with the standards IEC61010: in pollution degree 2, overvoltage
category (CAT I 600V, CAT II 300V) and double insulation.

CAT. I: Signal level, special equipment or parts of equipment, telecommunication,
electronic, etc., with smaller transient overvoltages than overvoltages CAT. II.

CAT. II: Local level, appliance, PORTABLE EQUIPMENT etc., with smaller transient
overvoltages than CAT. III

Use the Meter only as specified in this operating manual, otherwise the protection
provided by the Meter may be impaired.

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Model UT33B/C/D: OPERATING MANUAL

Safety Information(2)

In this manual, a Warning identifies conditions and actions that pose hazards to the
user, or may damage the Meter or the equipment under test.A Note identifies the
information that user should pay attention on.

International electrical symbols used on the Meter and in this Operating Manual are
explained on page 10.

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Model UT33B/C/D: OPERATING MANUAL

l Before using the Meter inspect the case. Do not use the Meter if it is
damaged or the case (or part of the case) is removed. Look for cracks or
missing plastic. Pay attention to the insulation around the connectors.
l Inspect the test leads for damaged insulation or exposed metal. Check
the test leads for continuity . Replace damaged test leads with identical
model number or electrical specifications before using the Meter.
l Do not apply more than the rated voltage, as marked on the Meter, between
the terminals or between any terminal and grounding.
l The rotary switch should be placed in the right position and no any
changeover of range shall be made during measurement is conducted to

Warning
To avoid possible electric shock or personal injury, and to avoid possible
damage to the Meter or to the equipment under test, adhere to the following
rules:

Rules For Safe Operation (1)

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Model UT33B/C/D: OPERATING MANUAL

prevent damage of the Meter.
l When the Meter working at an effective voltage over 60V in DC or 42V rms
in AC, special care should be taken for there is danger of electric shock.

l Use the proper terminals, function, and range for your measurements.
l Do not use or store the Meter in an environment of high temperature, humidity,

explosive, inflammable and strong magnetic field. The performance of the
Meter may deteriorate after dampened.

l When using the test leads, keep your fingers behind the finger guards.
l Disconnect circuit power and discharge all high-voltage capacitors before

testing resistance, continuity, diodes and current.
l Before measuring current, check the Meter’s fuses and turn off power to
the circuit before connecting the Meter to the circuit.
l Replace the battery as soon as the battery indicator appears. With a low
battery, the Meter might produce false readings that can lead to electric
shock and personal injury.

Rules For Safe Operation (2)

8

Model UT33B/C/D: OPERATING MANUAL

l Remove test leads and temperature probe from the Meter and turn the
Meter power off before opening the Meter case.
l When servicing the Meter, use only the same model number or identical
electrical specifications replacement parts.
l The internal circuit of the Meter shall not be altered at will to avoid damage
of the Meter and any accident.
l Soft cloth and mild detergent should be used to clean the surface of the
Meter when servicing. No abrasive and solvent should be used to prevent
the surface of the Meter from corrosion, damage and accident.

l The Meter is suitable for indoor use.
l Turn the Meter off when it is not in use and take out the battery when not

using for a long time.
l Constantly check the battery as it may leak when it has been using for some
time, replace the battery as soon as leaking appears. A leaking battery
will damage the Meter,

Rules For Safe Operation (3)

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Model UT33B/C/D: OPERATING MANUAL

International Electrical Symbols

Continuity Test

AC Current
DC Current

Double Insulated.

Low Battery.
Diode.
Fuse.

Safety Rules
Conforms to Standards of European Union.

Earth Ground

AC or DC

10

Model UT33B/C/D: OPERATING MANUAL

The Meter Structure (figure 1)

1) LCD Display

2) HOLD Button

3) Display Backlight Button

4) Rotary Switch

5) COM Input Terminal

6) 10A Input Terminal

7) Other Input Terminals

The Meter Structure

(figure 1)

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Model UT33B/C/D: OPERATING MANUAL

7

4

3

1

5

6

2

Functional Buttons

Below table indicated for information about the functional button operations.

Button Operation Performed

HOLD button

l Press BLUE button once to turn the display backlight on.
l Press BLUE button again to turn the display backlight off.
l Display backlight will NOT be automatically off unless pressing

the BLUE button

BLUE button

l Press HOLD once to enter hold mode.
l Press HOLD again to exit hold mode.
l In Hold mode, H is displayed and the present value is shown.

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation(1)

A. DC Voltage Measurement (see figure 2)

Warning
To avoid harms to you or damages to the Meter from electric shock, please do
not attempt to measure voltages higher than 500V although readings may be
obtained.

The DC Voltage ranges are: 200mV, 2000mV, 20V,
200V and 500V. To measure DC voltage, connect
the Meter as follows:

1. Insert the red test lead into theVΩmAterminal
and the black test lead into the COM terminal.

2. Set the rotary switch to an appropriate
measurement position in V range.

3. Connect the test leads across with the object
being measured.
The measured value shows on the display.

(figure 2)

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation (2)

Note

l If the value of voltage to be measured is unknown, use the maximum measurement

position (500V) and reduce the range step by step until a satisfactory reading
is obtained.

l The LCD displays “1” indicating the existing selected range is overload; it is

required to select a higher range in order to obtain a correct reading.

l In each range, the Meter has an input impedance of approx. 10MΩ. This loading

effect can cause measurement errors in high impedance circuits. If the circuit
impedance is less than or equal to 10kΩ, the error is negligible (0.1% or less).

l When DC voltage measurement has been completed, disconnect the connection

between the testing leads and the circuit under test.

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation (3)

B. AC Voltage Measurement (see figure 2)

Warning
To avoid harms to you or damages to the Meter from electric shock, please do

not attempt to measure voltages higher than 500Vrms although readings may
be obtained.

The AC voltage measurement positions are: 200V and 500V. To measure AC Voltage,
connect the Meter as follows:

1. Insert the red test lead into the VΩmA terminal and the black test lead into the
COM terminal.

2. Set the rotary switch to an appropriate measurement position in V range.

3. Connect the test leads across with the object being measured.
The measured value shows on the display, which is effective value of sine wave
(mean value response).

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation (4)

Note

l If the value of voltage to be measured is unknown, use the maximum measurement

position (500V) and reduce the range step by step until a satisfactory reading
is obtained.

l The LCD displays “1” indicating the existing selected range is overload, it is

required to select a higher range in order to obtain a correct reading.

l In each range, the Meter has an input impedance of approx. 10MΩ. This loading

effect can cause measurement errors in high impedance circuits. If the circuit
impedance is less than or equal to 10kΩ, the error is negligible (0.1% or less).

l When AC voltage measurement has been completed, disconnect the connection

between the testing leads and the circuit under test.

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation (5)

C. DC Current Measurement (see figure 3)

Never attempt an in-circuit current
measurement where the voltage between
terminals and ground is greater than 60V.
If the fuse burns out during measurement,
the Meter may be damaged or the operator
himself may be hurt. Use proper terminals,
function, and range for the measurement.
When the testing leads are connected to
the current terminals, do not parallel them
across any circuit.

Warning

( figure 3)

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Model UT33B/C/D: OPERATING MANUAL

The Model UT33B: the current measurement has 3 measurement positions
on the rotary switch: 200µA, 200mA and 10A.
The Model UT33C/UT33D: the current measurement has 4 measurement positions
on the rotary switch: 2000µA, 20mA, 200mA and 10A

To measure current, do the following:

1. Turn off power to the circuit. Discharge all high-voltage capacitors.

2. Insert the red test lead into the VΩmA or 10A terminal and the black test lead

into the COM terminal.

3. Set the rotary switch to an appropriate measurement position in A range.

4. Break the current path to be tested. Connect the red test lead to the more
positive side of the break and the black test lead to the more negative side
of the break.

5. Turn on power to the circuit.
The measured value shows on the display.

Measurement Operation (6)

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Model UT33B/C/D: OPERATING MANUAL

Note

l If the value of current to be measured is unknown, use the maximum measurement
position (10A)

l and reduce the range step by step until a satisfactory reading is obtained.
l When current measurement has been completed, disconnect the connection

between the testing leads
l and the circuit under test.

Measurement Operation (7)

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation (8)

D. Measuring Resistance (see figure 4)

( figure 4)

Warning
To avoid damages to the Meter or to the

devices under test, disconnect circuit
power and discharge all the high-voltage
capacitors before measuring resistance.

The Model UT33B/UT33C: The resistance

measurement positions are: 200Ω, 2000Ω¸,
20kΩ, 200kΩ and 20MΩ
The Model UT33D: The resistance measurement
positions are: 200Ω, 2000Ω, 20kΩ, 200kΩ,20MΩ
and 200MΩ
To measure resistance, connect the Meter as
follows:

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Model UT33B/C/D: OPERATING MANUAL

1. Insert the red test lead into the VΩmA terminal and the black test lead into the
COM terminal.

2. Set the rotary switch to an appropriate measurement position in Ω range.

3. Connect the test leads across with the object being measured.
The measured value shows on the display.

Note

l The test leads can add 0.1Ωto 0.3Ωof error to resistance measurement. To obtain

precision readings in low-resistance measurement, that is the range of 200Ω,

short-circuit the input terminals beforehand and record the reading obtained

(called this reading as X). (X) Is the additional resistance from the test lead.

Then use the equation:

measured resistance value (Y) (X) = precision readings of resistance.

l For high-resistance measurement (>1MΩ), it is normal taking several seconds

to obtain a stable reading.

l When resistance measurement has been completed, disconnect the connection

Measurement Operation (9)

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Model UT33B/C/D: OPERATING MANUAL

between the testing leads and the circuit under test.

Measurement Operation (10)

E. Diodes and Continuity Measurement (see figure 5)

( figure 5)

Testing Diodes

To avoid amages to the Meter or to the
devices under test, disconnect circuit
power and discharge all the high-voltage
capacitors before diodes.

Warning

Use the diode test to check diodes,
transistors, and other semiconductor
devices. The diode test sends a current
through the semiconductor junction, and
then measures the voltage drop

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Model UT33B/C/D: OPERATING MANUAL

across the junction. A good silicon junction
drops between 0.5V and 0.8V.
To test a diode out of a circuit, connect the Meter as follows:

1. Insert the red test lead into the VΩmA terminal and the black test lead into the
COM terminal.

2. Set the rotary switch to (The Model: UT33B) or (The Model: UT33C/
UT33D)

3. For forward voltage drop readings on any semiconductor component, place the
red test lead on the component’s anode and place the black test lead on the
component’s cathode.
The measured value shows on the display.

Note

l In a circuit, a good diode should still produce a forward voltage drop reading of

0.5V to 0.8V; however, the reverse voltage drop reading can vary depending on
the resistance of other pathways between the probe tips.

Measurement Operation (11)

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Model UT33B/C/D: OPERATING MANUAL

l Connect the test leads to the proper terminals as said above to avoid error display .

The LCD will display “1” indicating open-circuit for wrong connection. The unit
of diode is Volt (V), displaying the positive-connection voltage-drop value.

l When diode testing has been completed, disconnect the connection between

the testing leads and the circuit under test.

Measurement Operation (12)

The Model UT33C/UT33D: Testing for Continuity

To test for continuity, connect the Meter as below:

1. Insert the red test lead into the VΩmA terminal and the black test lead into the
COM terminal.

2. Set the rotary switch to .

3. Connect the test leads across with the object being measured.
The buzzer sounds if the resistance of a circuit under test is less than 70Ω.

Note

l The LCD displays “1” indicating the circuit being tested is open.

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Model UT33B/C/D: OPERATING MANUAL

l When continuity testing has been completed, disconnect the connection between

the testing leads and the circuit under test.

Measurement Operation (13)

F. Model UT33C: Temperature Measurement (see figure 6)

To avoid harms to you or damages to the
Meter, please do not attempt to input
voltages higher than 60V in DC or 30V in AC.

Warning

The Temperature measurement range is -40oC
~1000

o

C

or -40

o

F

~1832

o

F

. To measure

temperature, connect the Meter as follows:

1. Insert the red temperature probe into the

VΩmA

terminal and the black temperature

probe into the COM temperature.

( figure 6)

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Model UT33B/C/D: OPERATING MANUAL

2. Set the rotary switch to

o

C

or

o

F

.

3. Place the temperature probe to the object being measured.
The measured value shows on the display.

Note

l The Meter automatically displays the temperature value inside the Meter when

there is no temperature probe connection.

l The included point contact temperature probe can only be used up to 250

o

C(482oF).
For any measurement higher than that, the rod type temperature probe must
be used instead.

l When temperature measurement has been completed, disconnect the connection

between the testing leads and the circuit under test.

Measurement Operation (14)

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Model UT33B/C/D: OPERATING MANUAL

Measurement Operation (15)

G. The Model UT33B: Battery Test (see figure 7)

To avoid harms to you or damages to the Meter,
please do not attempt to input voltages higher
than 60V in DC or 30V in AC.

Warning

( figure 7)

To test the battery, proceed as follows:

1. Insert the red test into the VΩmA terminal and
the black test leads into the COM terminal.

2. Set the rotary switch to an appropriate
measurement position in range.

3. Connect the test leads across with the battery
being measured ensuring the polarity is correct.
The measured value shows on the display, which
is the voltage between the cathode and anode of
the battery.

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Model UT33B/C/D: OPERATING MANUAL

Note

l When battery testing has been completed, disconnect the connection between

the testing leads and the circuit under test.

Measurement Operation (16)

H. The Model UT33D: Square Wave Output

To avoid damages to the Meter, do not allow output terminals (red test lead)
to reach higher than 10V.

Warning

To measure square wave output proceed as follows:

1. Set the rotary switch to OUT.

2. The square wave signal outputs between VΩmA and COM Terminals.

Note

l The frequency is approx. 50Hz.
l The output scope higher than 3Vpp when it is loaded 1MΩ.

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Model UT33B/C/D: OPERATING MANUAL

l When square wave output testing has been completed, disconnect the connection

between the testing leads and the circuit under test.

General Specifications(1)

l Maximum Voltage (including transient overvoltage) between any Terminals

and Grounding: 500V rms.

l Fused Protection for VΩmA Input Terminal: 315mA, 250V fast type, φ5x20 mm
l 10A Terminal: Un-fused.
l Range: Manual ranging
l Maximum Display: Display: 1999.
l Measurement Speed: Updates 2~3 times /second.
l Temperature:

Operating: 0oC~40oC (32oF~104 oF).

Storage: -10oC~50oC (14oF~122oF).

l Relative Humidity: 75% @ 0

o

C - 30oC; 50% @ 31 - 40oC.

General Specifications

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Model UT33B/C/D: OPERATING MANUAL

l Altitude:Operating: 2000 m.

Storage: 10000 m.

l Battery Type: One piece of 9V Battery NEDA 1604 or 6F22 or 006P.
l Battery Deficiency: Display: .
l Negative reading: Display: .
l Overloading: Display: 1.
l Dimensions (HxWxL): 130 x 73.5 x 35mm.
l Weight: Approx. 156g (battery included).
l Safety/Compliances: IEC61010 CAT.I 600V overvoltage and double insulation

standard.

l Certification:

General Specifications(2)

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Model UT33B/C/D: OPERATING MANUAL

Accuracy: (a% reading + b digits), guarantee for 1 year.
Operating temperature: 23oC 5oC.
Relative humidity: <75%.
Temperature coefficient: 0.1 x (specified accuracy) / 1oC.

Accuracy Specifications(1)

A. DC Voltage

Remark: Input impedance: 10MΩ.

Range Resolution

200mV

2000mV

20V
200V
500V

Accuracy

UT33B UT33C UT33D

Overload

Protection

100µV

1mV

10mV

100mV

1V

(0.5%+2)

(0.8%+2)

250V DC or AC

500V DC or AC

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Model UT33B/C/D: OPERATING MANUAL

B. AC Voltage

Accuracy Specifications(2)

Remarks:

l Input impedance: approx. 5MΩ.
l Displays effective value of sine wave (mean value response).
l Frequency response 40Hz ~ 400Hz.

Range Resolution

Accuracy

UT33B UT33C UT33D

Overload

Protection

200V
500V

100mV

1V

(1.2%+10) 500V DC or AC

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Model UT33B/C/D: OPERATING MANUAL

Accuracy Specifications(3)

C. DC Current

Remark:

l At 10A Range: For continuous measurement 10 seconds and interval not less

than 15 minutes.

Range Resolution

200µA

2000µA

20mA

200mA

10A

Accuracy

UT33B UT33C UT33D

Overload

Protection

(1.2%+2)

(2%+5)

0.1µA
1µA

10µA

100µA

10mA

315mA, 250V

fast type fuse:

φ 5x20mm

Un-Fused

(1%+2)

(1%+2)

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Model UT33B/C/D: OPERATING MANUAL

D. Resistance

Accuracy Specifications(4)

Range Resolution

200Ω

2000Ω

20kΩ

200kΩ

20MΩ

200MΩ

Accuracy

UT33B UT33C UT33D

Overload

Protection

0.1Ω
1Ω

10Ω
100Ω
10kΩ

100kΩ

(0.8%+5)

(1%+5)

(0.8%+2)

[5%(reading-10)+10]

250V DC

or AC

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Model UT33B/C/D: OPERATING MANUAL

E. Diodes and Continuity Measurement (Continuity test only for UT33C/UT33D)

F. The Model UT33C: Temperature

1Ω Buzzer beeps at <70Ω

Range Resolution Remark Overload Protection

1mV

Displays approximate forward

voltage drop: 0.5V~0.8V.

250V DC or AC

Accuracy Specifications(5)

Range Resolution Remark Overload Protection

250V DC or AC

-40oC~150oC

150oC~1000oC

-40

o

F

~302

o

F

302

o

F

~1832

o

F

1

o

C

1

o

F

(1%+3)

(1.5%+15)

(1%+4)

(1.5%+15)

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Model UT33B/C/D: OPERATING MANUAL

G. The Model UT33B: Battery Test

Accuracy Specifications(6)

Range Resolution Internal Resistance

12V

9V

1.5V

10mV
10mV
10mV

H. The Model UT33D: Square Wave Output

Range

Illustration

Approx. output 50Hz square wave signal. As a simple signal
source with 47kΩ resistance output.

OUT

Remark:

l No overload protection.
l Make sure voltage output of calibrated equipment level is less than 10V to avoid

damages to the meter.

240Ω

1.8kΩ
30Ω

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Model UT33B/C/D: OPERATING MANUAL

This section provides basic maintenance information including battery and fuse
replacement instruction.

Maintenance(1)

A. General Service

l Periodically wipe the case with a damp cloth and mild detergent. Do not use

abrasives or solvents.

l To clean the terminals with cotton bar with detergent, as dirt or moisture in the

terminals can affect readings.

l Turn the Meter to OFF position when it is not in use and take out the battery

when not using for a long time.

Do not attempt to repair or service your Meter unless you are qualified to do
so and have the relevant calibration, performance test, and service information.
To avoid electrical shock or damage to the Meter, do not get water inside the
case.

Warning

37

Model UT33B/C/D: OPERATING MANUAL

l Do not store the Meter in a place of humidity, high temperature, explosive,

inflammable and strong magnetic field.

B. Replacing the Battery (see figure 8)

T o avoid false readings, which could lead to
possible electric shock or personal injury,
replace the battery as soon as the battery
indicator “ ”appears.

( figure 8)

Warning

Screw

To replace the battery:

1. Disconnect the connection between the
testing leads and the circuit under test,
and remove the testing leads away from
the input terminals of the Meter.

Maintenance(2)

38

Model UT33B/C/D: OPERATING MANUAL

2. Turn the Meter to OFF position.

3. Remove the screw from case bottom, and separate the case bottom from the
case top.

4. Remove the battery from the battery compartment.

5. Replace the battery with a new 9V battery (NEDA 1604 or 6F22 or 006P).

6. Rejoin the case bottom and case top, and reinstall the screw.

C. Replacing the Fuses (See figure 8)

Maintenance(3)

To avoid electrical shock or arc blast, or personal injury or damage to the
Meter, use specified fuses ONLY in accordance with the following procedure.

Warning

To replace the Meter’s fuse:

1. Disconnect the connection between the testing leads and the circuit under test,
and remove the testing leads away from the input terminals of the Meter.

2. Turn the Meter to OFF position.

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Model UT33B/C/D: OPERATING MANUAL

3. Remove the screw from case bottom, and separate the case bottom from the
case top.

4. Remove the fuse by gently prying one end loose, and then take out the fuse
from its bracket.

5. Install ONLY replacement fuses with the identical type and specification as
follows and make sure the fuse is fixed firmly in the bracket. 315mA, 250V, fast
type, φ 5x20mm.

6. Rejoin the case bottom and case top, and reinstall the screw.

Replacement of the fuses is seldom required. Burning of a fuse always results from
improper operation.

** END **

Maintenance(4)

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Model UT33B/C/D: OPERATING MANUAL

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Model UT33B/C/D: OPERATING MANUAL

Copyright 2002 Uni-Trend Group Limited.

All rights reserved.
Manufacturer:

Uni-Trend Technology (Dongguan) Limited
Dong Fang Da Dao
Bei Shan Dong Fang Industrial Development District
Hu Men Town, Dongguan City
Guang Dong Province
China
Postal Code: 523 925

Headquarters:
Uni-Trend Group Limited
Rm901, 9/F, Nanyang Plaza
57 Hung To Road
Kwun Tong
Kowloon, Hong Kong
Tel: [phone]
Fax: [phone]
Email: [e-mail]
http://www.uni-trend.com

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Model UT33B/C/D: OPERATING MANUAL