13
OPERATING INSTRUCTIONS
SAFETY PRECAUTIONS
W A R N I N G
The following precautions must be observed
to help prevent electric shock.
1.
When the oscilloscope is used to make measurements in
equipment that contains high voltage, there is al-ways a
certain amount of danger from electrical shock. The person
using the oscilloscope in such conditions should be a
qualified electronics technician or other-wise trained and
qualified to work in such circumstances. Observe the
TEST INSTRUMENT SAFETY recommendations listed
on the inside front cover of this manual.
2.
Do not operate this oscilloscope with the case removed
unless you are a qualified service technician. High voltage
up to 2100 volts is present when the unit is operating with
the case removed.
3.
The ground wire of the 3-wire ac power plug places the
chassis and housing of the oscilloscope at earth ground.
Use only a 3-wire outlet, and do not attempt to defeat the
ground wire connection or float the oscilloscope; to do so
may pose a great safety hazard.
4.
Special precautions are required to measure or observe
line voltage waveforms with any oscilloscope. Use the
following procedure:
a.
Do not connect the ground clip of the probe to either
side of the line. The clip is already at earth ground and
touching it to the hot side of the line may “weld” or
“disintegrate” the probe tip and cause possible injury,
plus possible damage to the scope or probe.
b.
Insert the probe tip into one side of the line voltage
receptacle, then the other. One side of the receptacle
should be “hot” and produce the waveform. The other
side of the receptacle is the ac return and no waveform
should result.
EQUIPMENT PROTECTION PRECAUTIONS
The following precautions will help avoid
damage to the oscilloscope.
1.
Never allow a small spot of high brilliance to remain
stationary on the screen for more than a few seconds. The
screen may become permanently burned. A spot will
occur when the scope is set up for X Y operation and no
signal is applied. Either reduce the intensity so the spot is
barely visible, apply signal, or switch back to normal
sweep operation. It is also advisable to use low intensity
with
AUTO
triggering and no signal applied for long
periods. A high intensity trace at the same position could
cause a line to become permanently burned onto the
screen.
2.
Do not obstruct the ventilating holes in the case, as this
will increase the scope’s internal temperature.
3.
Excessive voltage applied to the input jacks may
dam-age the oscilloscope. The maximum ratings of the
inputs are as follows:
CH 1 and CH2:
400 V dc + ac peak.
EXT TRIG:
300 V dc + ac peak.
Z-AXIS INPUT:
30 V ( dc and ac peak).
4.
Always connect a cable from the ground
terminal of the oscilloscope to the chassis of the
equipment under test. Without this precaution, the entire
current for the equipment under test may be drawn
through the probe clip leads under certain circumstances.
Such conditions could also pose a safety hazard, which the
ground cable will prevent.
5.
The probe ground clips are at oscilloscope and earth
ground and should be connected only to the earth ground
or isolated common of the equipment under test. To
measure with respect to any point other than the common,
use CH 2 – CH 1 subtract operation
(ADD
mode and
invert channel 2), with the channel 2 probe to the point of
measurement and the channel 1 probe to the point of
reference. Use this method even if the reference point is a
dc voltage with no signal.
