MARTINDALE MM42 User manual

Operating Instructions
Model MM42
Digital Multimeter
SAFETY INFORMATION
The following safety information must be observed
to ensure maximum personal safety during the
operation of this meter:
Do not use the meter if the meter or test leads look
damaged, or if you suspect that the meter is not
operating properly.
Never ground yourself when taking electrical
measurements. Do not touch exposed metal pipes,
outlets, fixtures, etc, which might be at ground
potential. Keep your body isolated from ground by
using dry clothing, rubber shoes, rubber mats, or
any insulating material.
Turn off power to the circuit under test before
cutting, unsoldering, or breaking the circuit. Small
amounts of current could be dangerous.
Use caution when working above 30V AC rms or
60V DC. Such voltages pose a shock hazard.
When using the probes, keep your fingers behind
the finger guards on the probes.
MM42 REV3 7/05
NOTE
This instrument is only to be used by a suitably
trained and competent person.
The symbols used on this instrument are:
Measuring voltage which exceeds the limits of the
multimeter may damage the meter and expose the
operator to a shock hazard. Always recognise the meter
voltage limits as stated on the front of the meter.
HIGH ENERGY SYSTEMS
GS38 advises fused test leads to be used when
working on high energy systems. Suitable leads are
Martindale TL55.
SPECIFICATIONS
Display: 3½ digit liquid crystal display (LCD) with a
maximum reading of 1999.
Polarity: Automatic, positive implied, negative
polarity indication.
Overrange: (1) or (-1) is displayed.
Zero: automatic.
Low Battery Indication: The is displayed when
the battery voltage drops below the operating level.
Measurement rate: 2.5 times per second, nominal.
Operating environment: 0°C to 50°C at < 70% R.H.
Storage temperature: -20°C to 60°C, 0 to 80% R.H.
with battery removed from meter.
Installation Categories: Category III: Fixed wiring
and installations within a building.
Accuracy: Stated accuracy at 23°C ± 5°C, < 75% R.H.
Battery life: 300 hours typical with carbon-zinc.
Battery: Single standard 9-volt battery, NEDA 1604,
JIS 006P, IEC 6F22, PP3.
Dimensions: 147mm (H)x 70mm (W)x 39mm (D).
Weight: Approx. 340g including battery and holster.
Accessories: One pair test leads, One spare fuse, 9V
battery (installed) and Operating Instructions.
DC VOLTS
Ranges: 2V, 20V, 200V, 600V
Resolution: 1mV (on 2V range)
Accuracy: ± (1.2% rdg + 1 dgt)
Input impedance: 1MΩ
Overload protection: 600VDC or AC rms
AC VOLTS: (50Hz - 500Hz)
Ranges: 200V, 600V
Resolution: 100mV (on 200mV range)
Accuracy: ± (2.0% rdg + 4 dgts)
Input impedance: 450kΩ
Overload protection: 600V DC or AC rms
DC CURRENT
Ranges: 2A
Resolution: 1mA
Accuracy: ± (2.5% rdg + 2 dgts)
Input protection: 2A/600V fast blow ceramic fuse
RESISTANCE
Ranges: 200Ω, 2kΩ, 20kΩ, 200kΩ, 2000kΩ
Resolution: 100mΩ (on 200Ωrange)
Accuracy: ± (1.5% rdg + 3 dgts) on 200Ωrange
± (1.5% rdg + 1 dgt) on 2kΩto 2000kΩ ranges
Open Circuit volts: 0.3V DC (3.0V DC on 200Ω
range)
Overload Protection: 500V DC or AC rms
DIODE TEST
Test current: 1.0mA ± 0.6mA
Accuracy: ± (3.0% rdg + 1 dgt)
Open circuit volts: 3.3V DC typical
Overload protection: 500V DC or AC rms
TRANSISTOR hFE
Ranges: 0 - 1000
Base current: 10µA DC approx. (Vce = 3.0V DC)
BATTERY TEST
Ranges: 1.5V, 9V
Resolution: 1mV, 10mV
Accuracy: ± (3.0% rdg + 2 dgts)
Loaded Current:150mA typical for 1.5V range
6mA typical for 9V range
Caution, risk of electric shock
Caution, refer to accompanying
documents
Equipment protected throughout
by Double Insulation (Class II)
Alternating current
Direct current
Ground
z
~
The instrument meets the requirements for double
insulation to BS EN 61010-1 at 600V Installation
Category III. Installation Category III (distribution
level) relates to transient overvoltage likely to be
found in fixed installation wiring.

MAINTENANCE
Battery Replacement
Power is supplied by a 9 volt "transistor" battery.
(NEDA 1604, IEC 6F22, PP3). The appears on
the LCD display when replacement is needed. To
replace the battery, remove the three screws from the
back of the meter and lift off the front case. Remove
the battery from case bottom.
Fuse Replacement
If no current measurements are possible, check for a
blown overload protection fuse. For access to fuse,
remove the three screws from the back of the meter
and lift off the front case. Replace only with the
original type 2A/600V, fast acting ceramic fuse. The
use of other fuses may cause damage to the meter,
invalidate the warranty and impair the instrument’s
safety. Domestic “Plug Top” fuses should not be
used.
OPERATION
Before taking any measurements, read the Safety
Information Section. Always examine the instrument
for damage, contamination (excessive dirt, grease,
etc.) and defects. If any abnormal conditions exist
do not attempt to make any measurements.
Voltage Measurements
1. Connect the red test lead to the "VΩA" socket and
the black test lead to the "COM" socket.
2. Set the Function/Range switch to the desired
voltage type (AC or DC) and range. If magnitude of
voltage is not known, set switch to the highest range
and reduce until a satisfactory reading is obtained.
3. Connect the test leads to the device or circuit
being measured.
4. For DC, a (-) is displayed for negative polarity;
positive polarity is implied.
Current Measurements
1. Connect the red test lead to the “VΩA” socket and
the black test lead to the “COM” socket.
2. Set the Function/Range switch to the 2A DC
range.
3. Remove power from the circuit under test and
open the normal circuit path where the
measurement is to be taken. Connect the meter IN
SERIES with the circuit.
4. Apply power and read the value from the display.
Resistance Measurements
1. Set the Function/Range switch to the desired
resistance range.
2. Remove power from the equipment under test.
3. Connect the red test lead to the "VΩA" socket and
the black test lead to the "COM" socket.
4. Connect the test leads to the points of
measurements and read the value from the display.
Diode Tests
1. Connect the red test lead to the "VΩA" socket and
the black test lead to the "COM" socket.
2. Set the Function/Range switch to the position.
3. Turn off power to the circuit under test. External
voltage across the components causes invalid
readings.
4. Touch probes to the diode. A forward-voltage drop
is about 0.6V (typical for a silicon diode).
5. Reverse probes. If the diode is good, "I" is
displayed. If the diode is shorted, ".000" or another
number is displayed.
6. If the diode is open, "I" is displayed in both
directions.
Transistor Gain Measurements
1. Set the Function/Range switch to the desired hFE
range (PNP or NPN type transistor).
2. Never apply an external voltage to the hFE sockets.
Damage to the meter may result.
3. Plug the transistor directly into the hFE sockets.
The sockets are labelled E, B and C for emitter, base
and collector.
4. Read the transistor hFE directly from the display.
Battery Test
1. Connect the red test lead to the "VΩA" socket and
the black test lead to the "COM" socket.
2. Set the Function/Range switch to the desired 1.5V
or 9V battery test range.
3. Connect the test leads to the 1.5Vdc battery under
test. Normally, a good 1.5Vdc battery will read above
1.25Vdc. Consult the battery manufacturer for
complete battery specifications to determine actual
battery life remaining and condition of battery.
Instrument Repairs and Spare Parts
Apart from the battery and fuse, there are no user
serviceable parts inside. If you suspect that the meter
is not operating properly, please check fuse, battery
and leads.
If the meter is still suspected of being faulty please
contact:
Metrohm House, Penfold Trading Estate,
Imperial Way, Watford, Herts. WD24 4YY, UK.
Tel: [phone] Fax: [phone]
E-mail: [email protected]
Web Site: http://www.martindale-electric.co.uk
MM42 REV3 7/05
Accessories
F1 - 1 x 1/4” 2A 600V ceramic - Ref: FUSE2600
(pack of 3)
Replacement original leads - Ref: TL16
Fused test leads to GS38 specification - Ref: TL55
Soft foam lined carry case - Ref: TC55
WARNING
Remove test leads before changing battery or
fuse or performing any servicing.