Changing The Battery - Hartig+Helling VM 42 D Bedienungsanleitung

Read the current measurement
from the display.
Max. permissible current 10A!
Important!
In the case of measurements up
to 200 mA, the unit is protected
by an internal fuse (200 mA/
250 V, quick-acting).
The 10 mA range is not fuse-
protected. You should therefore
ensure the correct connection,
otherwise accidents could occur.
Replace defective fuses only
against a fuse of the same type.
Measuring resistances
Test circuit:
VM 42 D
unknown
resistance
1. Connect the black test lead to
the ground jack " ".
COM
2. Connect the red test lead to jack
V Ω mA
" ".
3. Set the measuring range selector
Ω
to the " " range and select a
measuring range which
corresponds to the maximum
anticipated resistance.
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4. If the resistance is in a circuit,
disconnect all voltages and
discharge all capacitors.
5. Ensure that you do not get any
faulty readings as a result of the
circuit.
6. Avoid contact with your skin as
this may introduce contact
resistance into the measurement.
7. Connect the test lines with the
test item and read the value from
the display.
If the test heads are interconnected,
the test unit must display a value
of between " ".
000 - 006
If the display remains at " " or
1
shows a value larger than " ",
006
either the fuse or the test line could
be faulty. The battery could also
be flat.
The maximum test voltage in the
ohm range is around 3.2V!
The unit is equipped with an
audible continuity tester. To use
this tester, move the measuring
range selector to the " " range.
If the measured resistance is below
1.5 kΩ, a signal sounds and
continuity exists. If no signal
sounds, no connection exists.
This function is very useful for
locating related cable sections in
multi-pole lines.
The diode tester is a further useful
facility in the ohm range. To use
this function, set the measuring
range selector to the " 2k" range.
This position is ideal for testing
diodes. The display will show the
resistance of the diode.
Transistor tester
1. Select the " hFE " range with the
measuring range selector.
2. Plug the transistor to be tested
into the relevant test socket.
Ensure the correct connection
( E/B/C ) and transistor type
( ).
NPN/PNP
The test unit indicates the
transistor's current gain. If the value
is infinitely large (display " 1.... ") or
0 (display " 000 "), you can assume
that the transistor is faulty. If
necessary, compare the value with
a transistor of the same type.
The basic value for the display is
=10 µA.
as follows: Vce = 3.0V, I
b
Under no circumstances should
you plug a transistor into the
socket and at the same time
measure the voltage or current
with the test heads. This would
destroy the semi-conductor.
Hold a measurement value
If you want to hold a measurement
value in the display please press
the " HOLD " key. The display shows
the symbol " H ".
The value doesn't change now and
you can e. g. notice it very calmly.
After pressing the Hold key again
you can continue measuring.

Changing the battery

Change the battery if " " appears
on the display or measured values
differ excessively (example: you
measure 178 V AC at a 220 V AC
household socket).
1. Disconnect your test unit from
possible test circuits and remove
the test lines.
2. Loosen the two recessed head
screws on the rear of the unit.
3. Lift off the bottom of the casing.
4. Remove the old battery from the
unit.
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