Mastech MS8239B User Manual

MASTECH®

MS8239B

DIGITAL MULTIMETER

USER’S MANUAL

TABLE OF CONTENT

LIMITED WARRANTY AND LIMITATION OF

LIABILITY ................... 錯誤! 尚未定義書籤。

Out of the Box ................................................ 3

Accessories ..................................................... 4

Certification.................................................... 7

INTRODUCTION ........................................... 7

Overview ........................................................ 7

Figures and Components................................ 7

Buttons and Components............................ 8

Display Description ................................... 10

USING THE METER ..................................... 11

Preparation ............................................... 11

DC/AC Voltage Measurement ................... 12

AC/DC Current Measurement ................... 13

Resistance Measurement .......................... 15

Diode ......................................................... 16

Continuity .................................................. 16

1.5V 9V and 12V Battery Test ................... 17

1

SPECIFICATIONS ........................................ 18

General Specification ................................... 18

Technical Specifications ............................... 19

MAINTENANCE AND REPAIR ..................... 23

Repair ........................................................ 23

Test Leads Replacement ............................... 24

Replacing Batteries ..................................... 25

Replacing Fuse ............................................. 25

2

LIMITED WARRANTY AND
LIMITATION OF LIABILITY

This MS8239B product from MASTECH will be free from
defects in material and workmanship for one year from
the date of purchase. This warranty does not cover
fuses, disposable batteries, or damage from drops,
neglect, misuse, alteration, contamination, or abnormal
conditions of operation or handling. Resellers are not
authorized to extend any other warranty on MASTECH’s
behalf. To obtain service during the warranty period,
contact your nearest MASTECH authorized service
center to obtain return authorization information and
then send the product to that Service Center with a
description of the problem.

Out of the Box

Check the Meter and accessories thoroughly before using
the Meter. Contact your local distributor if the Meter or
any components are damaged or malfunction.

3

Accessories

WARNING
TO REDUCE THE RISK OF FIRE, ELECTRICAL SHOCK,
PRODUCT DAMAGE OR PERSONAL INJURY, PLEASE
FOLLOW THE SAFETY INSTRUCTIONS DESCRIBED IN THE
USER’S MANUAL. READ THE USER’S MANUAL BEFORE
USING THE METER.

WARNING
TO ENSURE SAFE OPERATION AND LIFE OF THE METER,
DO NOT PLACE THE METER IN ANY ENVIRONMENT WITH
HIGH PRESSURE, HIGH TEMPERATURE, DUST, EXPLOSIVE
GAS OR VAPOR.

 Test Leads 1set
 1.5V AAA Battery 2pcs
 User’s Manual

Safety Information

4

 Avoid shaking, dropping or any kind of

impacts when using or transporting the Meter.

 To avoid electric shock or personal injury,

repairs or servicing not covered in this manual
should be performed only by qualified
personnel.

 Avoid direct exposure to sunlight to ensure

extended life of the Meter.

 Do not place Meter in a strong magnetic field;

this may cause false readings.

 Use only the batteries indicated in the

Technical Spec.

 Avoid exposing batteries to humidity. Replace

batteries as soon as the low battery indicator
appears.

 Please keep the original packing for future

shipping purposes (ex. Calibration)

 After opening the box, check for any damage

during delivery.

5

Safety Symbols on the Meter

Important safety information, please refers
to the user manual

Earth ground

Indicates compliance with requirements for
double insulation

Possible of high voltage

Fuse must be replaced with ratings specified
in the manual.

Important Safety Information

 Never use the Meter to measure voltages that

might exceed 600V DC/AC above earth
ground.

 Always be careful when working with voltages

above 60V DC or 30V AC RMS. Keep fingers
behind the probe barriers while measuring.

 Never connect the Meter leads across a

voltage source while the rotary switch is in
the resistance, diode or continuity mode.
Doing so can damage the Meter.

 Do not perform resistance, diode and

continuity measurements on powered circuits.

6

 Inspect test leads and probes for cracks,

breaks or crazes on the insulation before
using the Meter.

 Repair or maintenance should be

implemented by trained personnel.

Certification

 CAT III: This meter has meet IEC61010-1

standard with an overvoltage category (600V
CAT III) and pollution degree 2.

 The Meter is compiled to EMC

requirements.

Introduction

Overview

The MS8239B is a compact and portable multifunction
digital multimeter featuring an easy-to-read LCD screen.
Basic functions include: AC/DC voltage, AC/DC current,
resistance, diode, continuity measurements and battery
test. This MS8239B is ideal for any entry level use.

7

Figures and Components

Buttons and Components

1. LCD (liquid-crystal display)

2. HOLD Button

3. Rotary Switch

4. 10A Input Jack

5. COM Input Jack

6. mA/V/Ω/ Input Jack

8

6

5

4

3

2

1

Front Panel

9

Display Description

1.

2. Hold

3. Reading Display

4. Polarity

10

Low Battery Indicator

Using the Meter

Preparation

 Switch on the power by turning the rotary

switch. If the battery voltage is lower than

2.8V, the“ ”symbol will appear and the
batteries should be replaced.

 The “ ” symbol next to the input lead

shows that the input voltage or current should
not exceed the specified value in order to
protect the internal circuit from damage.

 Turn the rotary switch to the required

function and range to be measured.

 Choose the highest range when the value to

be measured is unknown.

 When making connection, connect the

common test lead first and then the powered
test lead.

 Removed the charged test lead first when

disconnecting.

11

Readings Hold

WARNING
USE CAUTION WHEN MEASUREING HIGH VOLTAGE
CIRCUITS TO AVOID ELECTRICAL SHOCK AND
INJURY. DO NOT TEST VOLTAGES HIGHER THAN
DC/AC 600V.

 Press “HOLD” button to hold the readings of

current measurement.

 Press “HOLD” button again to release the hold.

DC/AC Voltage Measurement

 Plug the black test lead into “COM” jack and

the red test lead into “V” jack.

 Set the rotary switch to “V~” (AC), or “V ”

(DC) position in the corresponding range.

 Connect the test leads to the voltage source

or load for measurement.

 Read the result on the LCD. The polarity

symbol denotes the polarity of the end
connected by the red test lead.

12

NOTE:

WARNING
USE CAUTION WHEN MEASUREING HIGH VOLTAGE
CIRCUITS. TO AVOID ELECTRICAL SHOCK AND
INJURY. DO NOT TEST VOLTAGES HIGHER THAN
DC/AC 600V.

o At a small voltage range, unsteady readings

will appear before the test leads makes
contact with the circuit. This is normal since
the Meter is highly sensitive. When the test
leads are connected to the circuit, the true
reading will be shown.

o Under any range mode, when ‘1.’ is shown on

the LCD it means the measurement has
exceeded the allowable range. A higher range
should be selected.

o When the value to be measured is unknown,

select the highest range first and lower the
range accordingly.

AC/DC Current Measurement

13

 Plug the black test lead into the “COM” jack.
 Set the rotary switch to “A~” (AC) or “A ”

(DC) position in the corresponding range. For
example, when the current to be measured is
under 200mA, plug the red test lead into “mA”
jack and turn the switch to “200mA”; when
the current to be measured is over 200mA but
under 10A, plug the red test lead into the
“10A” jack and turn the switch to “10A”.

 Connect the test leads to the circuit.
 Read the result on the display.
 The polarity symbol denotes the polarity of

the red test lead.

NOTE:

o Under any range mode, when‘1.’is shown on

the LCD it means the measurement has
exceeded the allowable range; a higher range
should be selected.

o When the value to be measured is unknown,

select the highest range first and then lower
the range accordingly.

o “ ” indicates the maximum current of the

mA jack is 200mA and the maximum
current of the 10A jack is10A.At the 10A

14

jack, current exceeding the limit will blow the

WARNING
TO AVOID ELECTRICAL SHOCK AND INJURY
POWER OFF THE CIRCUIT AND DISCHARGE THE
CAPACITANCE BEFORE MEASURING RESISTANCE.

fuse.

Resistance Measurement

 Plug the black test lead into the “COM” jack

and the red test lead into the “Ω” jack.

 Set the rotary switch to the “Ω” position with

corresponding range.

 Connect the test leads to the ends of the

resistor or circuit.

 Read the numbers on the LCD.

NOTE:

Under any range mode, when only ‘1.’ is shown on the
LCD, it means the measurement has exceeded the range
and a higher range should be selected. When the input is
open, ‘1.’is displayed on the LCD to indicate overload.

For measuring resistance above 1MΩ, it may take a few

seconds to get a steady reading. This is normal for high
resistance measurements.

15

WARNING
TO AVOID ELECTRICAL SHOCK AND INJURY
POWER OFF THE CIRCUIT AND DISCHARGE THE
CAPACITANCE BEFORE MEASURING CONTINUITY

Diode

 Plug the black test lead into the COM jack and

the red test lead into the jack.

 Set the rotary switch to the range

position and select a proper range.

 Connect the red test lead to the anode and

the black test lead to the cathode of the diode
for testing.

 Read the result on the LCD.

NOTE:

o The Meter will show approximate forward

voltage drop of the diode.

o When the test leads are reversed or opened,

‘1.’will appear on the LCD.

Continuity

 Plug the black test lead into the “COM” jack

and the red test lead into “mA/V/Ω/ ”jack.

16

 Set the rotary switch to the “ ” position.
 Connect the test leads to two ends of the

circuit. If resistance of the circuit is less than
50Ωthe built-in buzzer will sound.

1.5V 9V and 12V Battery Test

 To check if the battery is in good or bad condition,

switch the rotary switch to “BATT” and choose the

voltage according to the battery type.

 Connect the red lead (+) to the (+) side of battery

and black lead (-) to the (-) side.

 Read off the result from the display.

17

Specifications

General Specification

 Maximum voltage between terminals and

earth ground: 600V DC/AC

 Operating altitude: max. 2000 meters (7000

ft.)

 Display: 3.5’’ LCD
 Maximum value of display: 1999
 Polarity indication: automatic; ‘-‘for negative

polarity.

 Overload indication: ‘1.’
 Sampling time: approx. 3 times/ second
 Function and Unit display
 Fuse protection 1: F200mA/250V

 Fuse protection 2: FF10A/600V
 Power Supply : 1.5V×2 AAA batteries
 Battery low indication: “
 Operating Temperature: 0°C to 40°C (32°F to

104°F )

 Storage Temperature: -10°C to 60°C (10°F to

140°F )

 Dimension: 147×76.2×41mm (5.8 x 3 x 1.6 in.)

18

” on LCD

 Weight: approximate 230g (7.6oz) including

Range

Resolution

Accuracy

200mV

0.1mV

± (0.5% of reading + 3

digits)

2V

1mV

20V

10mV

200V

100mV

600V

1V

± (0.8% of reading + 3

digits)

Technical Specifications

DC Voltage

Input Impedance: 1MΩ
Maximum input voltage: 600V DC or AC RMS.

NOTE:

o At small voltages range, unsteady readings

19

batteries

will appear before the test leads make contact
with the circuit. This is normal since the meter
is highly sensitive. When the test leads
connect to the circuit, the true reading will be
shown.

Range

Resolution

Accuracy

200V

0.1V

± (1.2% of reading + 10
digits)

600V

1V

Range

Resolution

Accuracy

200mA

0.1mA

±(1.2% of reading +5 digits)

AC Voltage

Input Impedance: 1MΩ
Maximum input voltage: 600V DC or AC RMS.
Frequency response: 40Hz~400Hz, sine wave RMS
(Average response)

NOTE:

o At small voltage ranges, unsteady readings

will appear before the test leads make contact
with the circuit. This is normal since the meter
is highly sensitive. When the test leads
connect to the circuit, the true reading will be
shown.

AC Current

20

10A

10mA

±(2.5% of reading +10
digits)

Range

Resolution

Accuracy

200mA

100μA

±(1.0% of reading + 5 digits)

10A

10mA

±(2.0% of reading + 10 digits)

Overload protection:

o mA: Fuse (F200mA/250V)
o 10A: Fuse (FF10A/600V) protection.

Maximum input current:

o mA: 200mA DC or AC RMS
o 10A: 10A DC or AC RMS

Frequency response: 40Hz~400Hz, sine wave RMS
(Average response)

NOTE:

When measured current is greater than 2A, continuous
measurement time cannot be more than2 minutes.
Disconnect the current and wait 10 minutes before
making another measurement.

DC Current

Overload protection:

21

o mA: Fuse (F200mA/250V)

Range

Resolution

Accuracy

200Ω

0.1Ω

±(0.8% of reading + 5 digits)

2kΩ

1Ω

20kΩ

10Ω

200kΩ

100Ω

2MΩ

1kΩ

Max. V

Resolution

Function

o 10A: Fuse (FF10A/600V)

Maximum input current:

o mA: 200mA DC or AC RMS
o 10A: 10A DC or AC RMS

NOTE:

When measured current is greater than 2A, continuous
measurement time cannot be more than2 minutes.
Disconnect the current and wait 10 minutes before
making another measurement.

Resistance

Open circuit voltage: ~0.25V
Overload protection: 250V DC or RMS AC

Diode Test

22

2V

1mV

Displaying approximate
forward voltage of
diode

Overload Protection: 250V DC or RMS AC

Function

Built-in buzzer will sound if resistance is lower
than 60Ω.

Measuring
Range

Resolution

Built-in Load
Resistance

12V

0.01V

300Ω

9V

0.01V

1.8kΩ

1.5V

0.001V

36Ω

Continuity Test

Overload Protection: 250V DC or RMS AC

Battery Test

Maintenance and Repair

Repair

Please follow these steps closely if the Meter is not
functioning properly:

23

WARNING

REPLACE THE TEST LEADS WITH IDENTICAL OR

COMPATIBLE LEADS. LEAD SPEC：1000V 10A.

 Check batteries; replace with new batteries if

low battery indicator “ ” appears.

 Follow User’s Manual to confirm all

procedures.

 Before sending Meter back for repair, include

a description of the problems encountered.
Remove batteries and pack Meter well to
avoid damage in delivery, Dawson does not
cover damage due to delivery.

 Repair or service not covered in this manual

should be performed only by the authorized
service center or qualified personnel.

Test Leads Replacement

Replace new leads if the current leads are worn.

24

Replacing Batteries

Follow these steps to replace batteries:

 Turn off the Meter.
 Loosen the battery compartment door screw, and

remove the door from the case bottom.

 Remove the batteries and replace the batteries

with new batteries.

 Reattach the battery compartment door to the case

bottom and tighten the screw.

Replacing Fuse

Fuses rarely need replacement. Almost all blows are the
result of operation error.

 Loosen the battery compartment door screws

like in the Replace Batteries.

 Remove the red rubber cover.
 Remove the screws located in the back.
 Replace the blown fuse with one at the

specified rating.

 Replace and tighten the screws located in the

back.

 Put back on the red rubber cover.
 Put the battery cover back and tighten the

screws.

25

Do not recycle

26