Mastech MY67 Instruction Manual

CONTENTS

1. SAFETY INFORMATION…………………………….1

2. DESCRIPTION……………………..…………………3

3. OPERATING INSTRUCTION………………………..6

3.1 MEASURING VOLTAGE……………………….6

3.2 MEASURING CURRENT………………………6

3.3 MEASURING RESISTANCE…………………..7

3.4 MEASURING FREQUENCY……………………7

3.5 MEASURING CAPACITANCE…………………8

3.6 CONTINUITY TEST…..………………………...8

3.7 DOIDE TEST……………………………………..8

3.9 TRANSISTOR TEST…………………………….9

4. SPECIFICATIONS…………………………………….9

5. ACCESSORIES………………………………………13

6. BATTERY & FUSE REPLACEMENT………………14

1. SAFETY INFORMATION

This multimeter has been designed according to
IEC-1010 concerning electronic measuring instruments
with an overvoltage category ( CATⅡ) and pollution 2.
Follow all safety and operating instructions to ensure
that the meter is used safely and is kept in good
operating condition.

1.1 PRELIMINARY

※ When using this meter, the user must observe all
normal safety rules concerning:

— Protection against the dangers of electrical current.
— Protection of the meter against misuse.
※ Full compliance with safety standards can be

guaranteed only if used with test leads supplied. If
necessary, they must be replaced with the same model or
same electronic ratings. Measuring leads must be in
good condition.

1.2 DURING USE

※ Never exceed the protection limit values indicated in
specifications for each range of measurement.
※ When the meter is linked to measurement circuit, do
not touch unused terminals.
※ When the value scale to be measured is unknown
beforehand, set the range selector at the highest
position.
※ Before rotating the range selector to change
functions, disconnect test leads from the circuit under

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test.
※ When carrying out measurements on TV or
switching power circuits, always remember that there
may be high amplitude voltages pulses at test points
which can damage the meter.
※ Never perform resistance measurements on live
circuits.
※ Always be careful when working with voltages
above 60V dc or 30V ac rms. Keep fingers behind the
probe barriers while measuring.

1.3 SYMBOLS

Important safety information, refer to the operating

manual.
Dangerous voltage may be present.

Earth ground
Double insulation (Protection class Ⅱ)

1.4 MAINTENANCE
Before opening the meter, always disconnect test ※

leads from all sources of electric current.

For continue protection against fire, replace fuse ※

only with the specified voltage and current ratings: F1:
2A/250V F2: 10A/250V

If any faults or abnormalities are observed, the ※

meter can not be used any more and it has to be

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checked out.

Never use the meter unless the back cover is in ※

place and fastened fully.

To clean the meter, use a damp cloth and mild ※

detergent only, do not use abrasives or solvents on it.

2. DESCRIPTION

This meter is an autoranging professional instrument
with 3 3/4 digit LCD display, capable of performing
functions:

- DC voltage measurement

- AC voltage measurement

- DC current measurement

- AC current measurement

- Resistance measurement

- Capacitance measurement

- Frequency measurement

- Diode test

- Transistor test

- Audible continuity test

Names of components

1-4. buttons

5. Rotary switch

6. A input jack

7. mA input jack

8. V/Ω/Hz input jack

9. COM input jack

10. Transistor input jack

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2.1 SELECT (Function selection button)

This button is used to select ACA or DCA measuring
mode.

2.2 RANGE (Auto/manual range selection button)

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This key is the auto/manual key. Power on default is
auto measurement, and press one time to switch to the
manual measurement. In manual measurement mode,
the system will jump up one mode for each press until
the highest mode, then return to the lowest mode as a
loop. If press the key over 2 seconds, the system will
switch back to auto measurement status. Frequency
and capacitance measurement cannot use manual
measurement. Fox example, at voltage range the
changes are as the figure.

2.3 REL (Relative value measurement)

The button is for relative value measurement except Hz,
diode and continuity.
Push the button to get relative measurement mode,
“REL” annunciate display on LCD. But store the

displayed reading as a reference value. In the Relative

mode, the value shown on the LCD is always the
difference between the stored reference value and the
present reading. If the new reading is the same as the
reference value, the display will be zero.

2.4 DATA HOLD

When this button is pushed, the display will keep the
last reading and “ ” symbol will appear on the LCD.
Pushing it again returns the meter to normal mode.

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2.5 INPUT JACKS

The unit has four input jacks that are protect against
overload to the limits. During use, connect the black test
lead to the COM jack and the red test lead as shown
below:

Function

Red lead

connection

Input limits

V V/Ω/Hz 1000V dc or 750V rms ac
Ω V/Ω/Hz 250V dc or rms ac

V/Ω/Hz 250V dc or rms ac

V/Ω/Hz 250V dc or rms ac

μA/mA mA 500mA dc or rms ac

A A 10A dc or rms ac

μA/mA and A ranges are protected by fuses.

3. OPERATING INSTRUCTION

3.1 MEASURING VOLTAGE

1. Connect the black test lead to the COM jack and the

red test lead to the V/Ω jack.

2. Set the rotary switch at the desired V or V ~

range position and connect test leads across the
source or load under measurement.

3. Read LCD display. The polarity of the red connection

will be indicated when making a dc voltage
measurement.

3.2 MEASURING CURRENT

1. Connect the black test lead to the COM jack and the

read test lead to the mA jack for a maximum of 500mA.

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For a maximum of 10A, move the red lead to the A jack.

2. Set the function switch at μA, mA or A range to be

used and push “SELECT” button to select DCA or ACA
measuring mode.

3. Connect test leads in series with the load under

measurement.

4. Read LCD display. The polarity of the red lead

connection will be indicated when making a DC
measurement.

3.3 MEASURING RESISTANCE

1. Connect the black test lead to the COM jack and the

red test lead to the V/Ω/Hz jack. (NOTE: The polarity of
red lead connection is positive “＋”)

2. Set the rotary switch at Ω position and connect test

leads across the resistance under measurement. Read
LCD display.

NOTE:

1. For resistance above 1MΩ, the meter may take a few

seconds to stabilize reading.

2. When the input is not connected, i.e. at open circuit,

the figure “OL” will be displayed for the overrange
condition.

3. When checking in - circuit resistance, be sure the

circuit under test has all power removed and all
capacitors are full discharged.

3.4 MEASURING FREQUENCY

1. Connect the black test leads to the COM jack and the

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red test lead to the V /Ω/Hz jack.

2. Set the rotary switch at Hz position and connect test

leads across the source or load under measurement.

3.5 MEASURING CAPACITANCE

1. Set the rotary switch at desired position.

2. Before inserting capacitor under measurement into

capacitance testing socket, be sure that the capacitor
has been discharged fully.

3. When measuring capacitors with shorter leads, a

testing adapter is provided with the meter. Insert the
adapter into the capacitance testing socket on the front
panel to continue measurements.

WARNING!

To avoid shock, be sure the capacitor measuring
adapter has been removed before changing to another
function measurement.

3.6 CONTINUITY TEST

1. Connect the black test lead to the COM jack and the

red test lead to the V/Ω/Hz jack (Note: the polarity of
red lead connection is positive “+”).

2. Set the rotary switch at position and connect test

leads across two points of the circuit under testing. If
continuity exists ( i.e. resistance less than about 50Ω ),
built — in buzzer will sound.

3.7 DIODE TEST

1. Connect the black test lead to the COM jack and the

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red test lead to the V/Ω/Hz jack. ( NOTE: The polarity of
red lead connection is positive“ + ”)

2. Set the rotary switch at position and connect the

red lead to the anode, the black lead to the cathode of
the diode under testing. The meter will show the approx.
Forward voltage drop of the diode.

3.8 TRANSISTOR TEST

1. Set the rotary switch at hFE position.

2. Identify whether the transistor is NPN or PNP type

and locate Emitter, Base and Collector lead. Insert
leads of the transistor to be tested into proper holes of
the testing socket on the front panel.

3. LCD display will show the approximate hFE value at

the test condition of base current 10µA and Vce 3.2V.

4. SPECIFICATIONS

Accuracy is specified for a period of one year after
calibration and at 18°C to 28°C (64°F to 82°F) with
relative humidity to 80%.
Accuracy specifications are given as:
± % of reading ± number of least significant digits.

4.1 GENERAL

MAXIMUM VOLTAGE BETWEEN TERMINALS AND
EARTH GROUND: 1000V DC or 700 rms AC (sine)
FUSE PROTECTION: µA, mA: F 500mA/250V

A: F 10A/250V

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POWER SUPPLY: 9V battery, NEDA 1604 or 6F22
DISPLAY: LCD, 3999 counts MAX, updates 2-3/sec
MEASURING METHOD:
Dual - slope integration A/D converter
OVERRANGE INDICATION:
“OL” figure only on the display
POLARITY INDICATION:
“—” displayed for negative polarity
LOW BATTERY INDICATION:“ ”displayed
OPERATING TEMPERATURE:
0°C to 40°C (32°F to 104°F)
STORAGE TEMPERATURE:

-10°C to 50°C (14°F to 122°F)

DIMENSION: 91×189×31.5mm
WEIGHT: 310g (including battery)

4.2 AC VOLTAGE

Range Resolution Accuracy

400mV

0.1mV --

4V 1mV

40V

10mV

400V

100mV

± 0.5 % of rdg ±

0.2% of full

scale ± 2 digit

750V

1V ± 0.8 % of rdg ± 2 digits

Input Impedance: 10MΩ.
Frequency Range: 40Hz to 400Hz
Response: Average, calibrated in rms of sine wave

4.3 DC VOLTAGE

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Range Resolution Accuracy

400mV

0.1mV ± 0.8 % of rdg ± 2 digit

4V 1mV ± 0.5 % of rdg ± 2 digit

40V

10mV ± 0.5 % of rdg ± 2 digit

400V

100mV ± 0.5 % of rdg ± 2 digit

1000V

1V ± 0.8 % of rdg ± 2 digits

Input impedance: 10MΩ, more than 100MΩ at 400mV
range.

4.4 DC CURRENT

Range Resolution

Accuracy

400µA 0.1µA ± 0.8 % of rdg ± 2 digits

4mA 1µA ± 0.8 % of rdg ± 2 digits

40mA 10µA ± 0.8 % of rdg ± 2 digits

400mA

0.1mA ± 1.2% of rdg ± 2 digits

10A 10mA ± 2.0 % of rdg ± 5 digits

Overload protection: F 500mA fuse for µ A and mA
ranges, F 10 A fuse for A range.

4.5 AC CURRENT

Range Resolution

Accuracy

400µA 0.1µA

± (0.8~8.0)% of rdg

± 3 digits

4mA 1µA ± 0.8% of rdg ± 3 digits

40mA 10µA ± 0.8% of rdg ± 3 digits

400mA 0.1mA ± 1.2% of rdg ± 3 digits

10A 10mA ± 2.0 % of rdg ± 5 digits

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Overload protection: F 500mA fuse for µ A and mA
ranges, F 10 A fuse for A range.
Frequency Range: 40Hz to 400Hz
Response: Average, calibrated in rms of sine wave

4.6 RESISTANCE

Range Resolution Accuracy

400Ω 0. 1Ω ± 0.8% of rdg ± 3 digits

4KΩ 1Ω ± 0.8% of rdg ± 1 digits

40KΩ 10Ω ± 0.8% of rdg ± 1 digits

400KΩ 100Ω ± 0.8% of rdg ± 1 digits

2MΩ 1KΩ ± 0.8% of rdg ± 1 digits

40MΩ 10KΩ ± 1.2% of rdg ± 2 digits

Max. open circuit voltage: 3.2V

4.7 CAPACITANCE

Range Resolution Accuracy

4nF 1pF

40nF 10pF

400nF 100pF

4µF 1nF

40µF 10nF

200µF 100nF

± 3.0% ± 20

4.8 FREQUENCY

Range Resolution Accuracy

100kHz 1Hz ± 2 % ± 5

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4.9 DIODE

Function Resolution Test

current

Open circuit
voltage

1mV 25µA 3.0V

4.10 AUDIBLE CONTINUITY

Function

Description

If resistance is lower than 50Ω, built-in

buzzer will sound.

4.11 TRANSISTOR

Function Range Base current Vce

hFE 1 to 1000

25µA 3.0V

5. ACCESSORIES

5.1 SUPPLIED WITH THE MULTIMETER

Test leads Electric Rating 1500V, 10A 1 couple
Battery 9V NEDA 1604 or 6F22 1 pcs
Operating Manual 1 pcs
Holster 1 pcs
Capacitance Testing Adapter 1 pcs

5.2 HOW TO USE THE HOLSTER

The holster is used to protest the meter and to make the
measurement more comfortable, it comes with tow
stands installed together. The figure shows how to use
the holster to:

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A: Support the meter with a standard angle.
B: Support the meter with a small angle using the little
stand
C: Hang the meter on the wall using the little stand.
Take the little stand off from the back side of the large
and insert it into holes located upper on the holster.
D. hold test leads

6. BATTERY & FUSE REPLACEMENT

If the sign“ ” appears on the LCD display, it
indicates that battery should be replaced.
Remove screws on the back cover and open the case.
Replace the exhausted battery with a new one.

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Fuse rarely need replacement and blow almost always
as a result of the operator’s error. Open the case as
mentioned above, and then take the PCB out from the
front cover. Replace the blown fuse with same ratings.

WARNING

Before attempting to open the case, be sure that test
leads have been disconnected from measurement
circuits to avoid electric shock hazard.
For protection against fire, replace fuse only with
specified ratings:
F1: 200mA/250V (quick acting)
F2: F20A/250V

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