Major tech MTD73A User manual

MTD73A
800A AC True RMS
Digital Clamp Meter
Instruction Manual

Safety
International Safety Symbols
This symbol, adjacent to another symbol or
terminal, indicates the user must refer to the
manual for further information.
This symbol, adjacent to a terminal, indicates that,
under normal use, hazardous voltages may be
present.
Double insulation.
Application around and removal from uninsulated
hazardous live conductors is permitted.
SAFETY NOTES
•Do not exceed the maximum allowable input range of
any function.
•Do not apply voltage to meter when resistance
function is selected.
•Set the function switch OFF when the meter is not in
use.
•Remove the battery if meter is to be stored for longer
than 60 days.
WARNINGS
•Set function switch to the appropriate position before
measuring.
•When measuring volts do not switch to
current/resistance modes.
•Do not measure current on a circuit whose voltage
exceeds 600V.
•When changing ranges always disconnect the test
leads from the circuit under test.

CAUTIONS
•Improper use of this meter can cause damage, shock,
injury or death. Read and understand this user manual
before operating the meter.
•Always remove the test leads before replacing the
battery or fuses.
•Inspect the condition of the test leads and the meter
itself for any damage before operating the meter.
Repair or replace any damage before use.
•Use great care when making measurements if the
voltages are greater than 25VAC RMS or 35VDC. These
voltages are considered a shock hazard.
•Always discharge capacitors and remove power from
the device under test before performing Diode,
Resistance or Continuity tests.
•Voltage checks on electrical outlets can be difficult and
misleading because of the uncertainty of connection to
the recessed electrical contacts. Other means should
be used to ensure that the terminals are not "live".
•If the equipment is used in a manner not specified by
the manufacturer, the protection provided by the
equipment may be impaired.
Function
Maximum Input
A AC
800A AC
V DC, V AC
600V DC/AC
Resistance, Capacitance, Frequency,
Diode Test，Temperature.
250V DC/ AC

Description
Meter Description
1. NCV Test
2. Current clamp
3. LED Flashlight
4. Non-contact AC voltage indicator light
5. Clamp trigger
6. Rotary Function switch
7. SELECTOR mode range button / Flashlight
8. Data Hold button
9. REL button for Relative Measurement
10. Flashlight and LCD backlight button
11. LCD display
12. COM input jack
13. V Ω Diode Continuity CAP TEMP Hz% jack
14. Battery Cover

Display icons Description
HOLD Data Hold
Minus sign Negative reading display
0 to 3999 Measurement display digits
NCV Non-Contact Voltage
AUTO Auto Range mode
DC Direct Voltage
AC Alternating Current/Voltage
Low battery
mV or V Milli-volts or Volts (Voltage)
ΩOhms (Resistance)
A Amperes (Current)
F Farad (Capacitance)
Hz/% Hertz (Frequency)/Percent(duty ratio)
oC Celsius units (Temperature)
n, m, μ, M, k Unit of measure prefixes: nano, milli, micro,
mega, and kilo
•))) Continuity test
Diode test
Accessories supplied with Meter
Operating manual, 1 x red and 1 x black test lead set, Air
temperature probe, 2 x 1.5V AAA Batteries, Carrying case

Specifications
Function
Range
Resolution
Accuracy
(% of reading +
digits)
AC
Current
4A
1mA
< 40A: (3.0%
rdg + 5digits)
˃40A: (2% rdg
+ 5 digits)
40A
10mA
400A
100mA
800A
1A
Over range protection: Maximum input 1000A
Accuracy specified from 5% to 100% of the measuring range
Frequency Response: 40Hz to 1kHz True RMS
Function
Range
Resolution
Accuracy
(% of
reading +
digits)
AC Voltage
(Auto
Ranging)
4V
1mV
+1.0% of rdg
+ 5digits
40V
10mV
400V
100mV
600V
1V
Input impedance 10MΩ. Overload protection 1000V DC or
750V AC peak value
Frequency response 600V at 40Hz to 1kHz (sine), other ranges
50/60Hz (all wave)

Function
Range
Resolution
Accuracy
(% of reading +
digits)
DC Voltage
(Auto
Ranging)
400mV
0.1mV
+1.0% of rdg +
5digits
4.00V
1mV
+0.5% of rdg +
5digits
40.0V
10mV
400V
0.1V
600V
1V
Input impedance on 400mV range ˃ 40MΩ all other ranges
10MΩ. Overload protection 1000V DC or 750V AC peak value
Function
Range
Resolution
Accuracy
(% of reading +
digits)
Resistance
(Auto
Ranging)
400Ω
0.1Ω
+0.8% of rdg +
5digits
4kΩ
1Ω
+0.8% of rdg +
3digits
40kΩ
10Ω
400kΩ
100Ω
4MΩ
1kΩ
40MΩ
10kΩ
+1.0% of rdg +
5digits
Input Protection: 250V DC or 250V AC RMS
Note: a. On 400Ω range, short the test leads to measure lead
resistance, then subtract the value from the real measurement
b. When measuring resistance over 1MΩ, it is normal that the
reading reacts slowly, wait until reading is stable.
Warning DO NOT apply voltage to this range

Function
Range
Resolution
Accuracy
(% of reading +
digits)
Capacitance
(Auto-
ranging)
4nF
0.nF
(5% reading +
20 digits)
40nF
0.01nF
400nF
0.1nF
(2.5% reading
+ 5 digits)
4uF
0.001µF
40uF
0.01µF
400uF
100nF
(5% reading +
10 digits)
4mF
1uF
40mF
10uF
Input Protection: 250V DC or 250V AC RMS
Ensure capacitors are discharged before measuring value
Warning DO NOT apply voltage to this range
Function
Range
Resolution
Accuracy
(% of reading +
digits)
Frequency
(Auto
Ranging)
10Hz
0.01Hz
(0.5% reading
+ 4 digits)
100Hz
0.1Hz
1kHz
1Hz
10kHz
10Hz
100kHz
100Hz
1MHz
1kHz
10MHz
10kHz
Input Protection: 250V DC or 250V AC RMS
Input sensitivity ˃ 0.7V
Warning DO NOT apply voltage to this range

Function
Range
Resolution
Accuracy
(% of
reading +
digits)
Temperature
-40°C to 1000°C
1°C
< 400°C:
+1.0% of rdg
+ 5°C
≥ 400°C:
+1.5% of rdg
+ 5°C
Input Protection: 250V DC or 250V AC RMS
Sensor: Type K Banana Plug Thermocouple
Warning DO NOT apply voltage to this range
Input Protection: 250V DC or 250V AC RMS
Warning DO NOT apply voltage to Continuity range
Function
Testing Condition
Reading
Diode
Forward DCA is approx.
0.8mA, open circuit
Voltage MAX. 2.2V
Diode forward voltage
drop
Continuity
Open circuit Voltage
MAX. 2V
Buzzer makes a
continuous sound
while resistance is less
than (50)

General Specifications
Clamp jaw opening 28mm approx.
Display 4000 Count (3-3/4 digits backlit LCD
Low Battery indication is displayed
Over-range indication ‘OL’ display
Measurement rate 3 readings per second, nominal
Temperature sensor Type K thermocouple 4mm terminals
Input Impedance 10M(VDC and VAC)
AC response Average Reading (AAC and VAC)
ACV Bandwidth 2KHZ
Operating Temperature 5oC to 40oC (41oF to 104oF)
Storage Temperature -20oC to 60oC (-4oF to 140oF)
Operating Humidity Max 80% up to 31oC (87oF)
Decreasing linearly to 50% at 40oC
(104oF)
Storage Humidity <80%
Operating Altitude 2000 meters (7000ft.) maximum.
Battery 2 x 1.5V AAA Battery
Battery life Approx. 30h (backlight ON), Approx.
100h (backlight OFF)
Auto power OFF After approx. 15 minutes
Dimensions 123 (W) x 270 (D) x 39 (H)mm
Weight 280g
Safety For indoor use and in the requirement
For double insulation IEC1010-1(2001):
EN61010-2-030, EN61010-2-032,
EN61010-2-033 Overvoltage Category
III 600V, Pollution Degree 2.
Operation
NOTES: Read and understand all Warning and Caution
statements in this operation manual prior to using this
meter. Set the function select switch to the OFF position
when the meter is not in use.

AC Current Measurements
WARNING: Ensure that the test leads are disconnected from the
meter before making current clamp measurements.
1. Set the Function switch to the Range. If the
approx. range of the measurement is not known, select
Auto Range.
2. Press the △/REL button to zero the meter display.
3. Use SELECT Button to select AC
4. Press the trigger to open jaw. Fully enclose only one
conductor. For optimum results, centre the conductor
in the jaw.
5. The clamp meter LCD will display the reading.

AC Voltage Measurement
1. Insert the black test lead into the negative COM
terminal and the red test lead into the positive V/
terminal.
2. Set the function switch to the position.
3. Connect the test leads in parallel to the circuit under
test.
4. Read the voltage measurement on the LCD display.
DC Voltage Measurement
1. Insert the black test lead into the negative COM
terminal and the red test lead into the positive V/
terminal.
2. Set the function switch to the position.
3. Connect the test leads in parallel to the circuit under
test.
4. Read the voltage measurement on the LCD display.

Resistance Measurement
1. Insert the black test lead into the negative COM
terminal and the red test lead
into the positive V/terminal.
2. Set the function switch to the
position.
3. Use SELECT Button to select 
4. Touch the test probe tips across
the circuit or component under
test. It is best to disconnect one
side of the device under test so
the rest of the circuit will not
interfere with the resistance reading.
5. For Resistance tests, read the resistance on the LCD
display.
Capacitance Measurement
WARNING: To avoid electric shock, discharge the capacitor
under test before measuring.
1. Insert the black test lead into the
negative COM terminal and the
red test lead into the positive
V/terminal.
2. Set the function switch to the
position.
3. Use SELECT Button to select nF
4. Touch the test probe tips across the circuit or
component under test. It is best to disconnect one
side of the device under test so the rest of the circuit
will not interfere with the resistance reading.
5. Capacitance value displayed on the LCD display.

Frequency Measurement
1. Insert the black test lead into the negative COM
terminal and the red test lead into the positive V/
terminal.
2. Set the function switch to the
Hz position.
3. Touch the test probe tips
across the circuit or
component under test. It is
best to disconnect one side
of the device under test so
the rest of the circuit will not
interfere with the resistance
reading.
4. Frequency measurement can
be read on the LCD display.
Temperature Measurements
1. Set the function switch to the oCposition.
2. Insert the Temperature Probe into the negative COM
and the V/positive jacks, observing polarity.
3. Touch the Temperature Probe head to the device
under test. Continue to touch the part under test with
the probe until the reading stabilizes.
4. Read the temperature on the display. The digital
reading will indicate ambient temperature if no probe
is inserted.
WARNING: To avoid electric shock, be sure the thermocouple
probe has been removed before changing to another
measurement function.

Continuity Measurements
1. Insert the black test lead into the negative COM
terminal and the red test lead into the positive V/
terminal.
2. Set the function switch to the position
3. Use SELECT Button to select . The display icons will
change when the SELECT button is pressed.
4. Touch the Test Probe tips across the circuit or
component under test.
5. If the resistance is < 50Ω, the buzzer tone will sound.
Diode Test
1. Insert the black test lead into the negative COM
terminal and the red test lead into the positive V/
terminal
2. Set the function switch to position
3. Use SELECT Button to select . The display icons
will change when the SELECT button is pressed.
4. Touch the test probe tips to the diode or
semiconductor junction under test. Note the meter
reading
5. Reverse the test lead polarity by reversing the red and
black leads. Note the reading
6. The diode or junction can be evaluated as follows:
•If one reading displays a value (typically 0.400V to
0.900V) and the other reading displays OL, the
diode is good.
•If both readings display OL device is open
•If both readings are very small or “0”, the device is
shorted

Non-Contact AC Voltage Measurements
1. Touch the probe tip to the hot (LIVE) conductor or insert
into the hot (LIVE) side of the electrical outlet.
2. If AC voltage is present, the detector red LED light will
illuminate.
a. NOTE: The conductors in electrical cord sets are
often twisted. For best results, rub the probe tip
along a length of the cord to assure placing the tip
in close proximity to the live conductor.
b. NOTE: The detector is designed with high
sensitivity. Static electricity or other sources of
energy may randomly trip the sensor. This is normal
operation
Data HOLD / Key
1. To freeze the LCD reading, press the button. While
data hold is active, the icon appears on the LCD.
Press the button again to return to normal
operation.
2. The LCD is equipped with backlighting for easier viewing,
especially in dimly lit areas. Press the button for 2
seconds to turn the LCD backlight on and off.
Flashlight
Hold down the SELECT Key for 2 seconds to turn on and off
the flashlight.
WARNING: Risk of Electrocution. Before use, always
test the Voltage Detector on a known live circuit to
verify proper operation

REL Mode
This sets the relative point to measure against the next reading.
Press the REL key to enter the Relative Measurement Mode, this
function resets the display to zero.
Automatic Power OFF
In order to conserve battery life, the meter will automatically
turn off after approximately 15 minutes. To turn the meter on
again, turn the rotary function switch to the OFF position and
then to the desired function range.
To cancel the auto power off function, press SELECT button and
turn on the power with the rotary switch at the same time.
Maintenance
WARNING: To avoid electrical shock, disconnect the meter
from any circuit, remove the test leads from the input
terminals, and turn OFF the meter before opening the case.
Do not operate the meter with an open case.
Cleaning and Storage
Periodically wipe the case with a damp cloth and mild detergent;
do not use abrasives or solvents. If the meter is not to be used
for 60 days or more, remove the battery and store it separately.

Battery Replacement
1. When the LCD displays , please replace the
battery to ensure correct readings
2. Remove the Phillips head screw that secures the rear
battery door
3. Open the battery compartment
4. Replace the 2 x 1.5V AAA battery, recommend Alkaline
batteries for longer use
5. Secure the battery compartment