Removal of the case or rear cover of an instru-
After soldering, disconnect the iron from its
ment not equipped with an interlock will allow
power supply and let it cool before you store it.
access to circuits carrying voltages dangerous
to human life.
Do not change tubes or make adjustments in-
Test equipment is precision equipment that must
side equipment with the high-voltage supply
be handled with care if it is to perform its designed
Under certain conditions, dangerous potentials
Some hazards to avoid when using test equipment
may exist in circuits. With the power controls
include rough handling, moisture, and dust. Bumping
in the OFF position, capacitors can still retain
or dropping a test instrument may distort the
their charge. Therefore, to avoid electrical
calibration of the meter or short-circuit the elements
shock, always de-energize the circuit, discharge
of an electron tube within the instrument.
the capacitors, and ground the circuit before
Moisture effects are minimized in some types of
working on it.
electronic test equipment, such as signal generators
Only authorized maintenance personnel with
and oscilloscopes, by built-in heaters. These heaters
proper approval should be permitted to gain
should be operated for several minutes before high
access to enclosures, connect test equipment, or
voltage is applied to the equipment.
test energized circuits or equipment.
Meters are the most delicate parts of test
Circuits should be de-energized and checked
equipment. You should protect a meter by ensuring
that the amplitude of the input signal being tested is
within the range of the meter.
energized and checked for voltage at various
Since the moving coils of the meter in electronic
test equipment are of the limited-current type, they can
When a circuit or a piece of equipment is
be permanently damaged by excessive current. To
energized, NEVER service, adjust, or work on
avoid such an occurence, you should observe the
it without the assistance of another person.
following safety precautions and procedures when
using test equipment:
Never place a meter near a strong magnetic
As an IC Electrician, you will be working with
Whenever possible, make the connections
various hand tools on a daily basis. For your safety,
when the circuit is de-energized.
you should take certain precautions when working
with hand tools.
When connecting an ammeter or the current
coil of a wattmeter or other current-measuring
Keep your tools in good condition, and never use
device, always connect the coils in series with
damaged tools. Tools having plastic or wooden
the load--NEVER ACROSS THE LINE.
handles that are cracked, chipped, splintered, or
broken may result in injuries to personnel from cuts,
When voltmeters are used, they should always
bruises, particles striking the eye, and the like.
be connected in parallel with the line.
Use each tool only for the job for which it was
Extend wires attached to an instrument over the
designed. Be careful to avoid placing tools where they
back of the workbench or worktable on which
could fall into mechanical or electrical equipment.
the instrument is placed and away from
observers--never over the front of the work-
Metallic tools used for working on electrical or
electronic equipment must be covered with an
electrical insulating material. The tools must be coated
Place a mat or folded cloth under the test instru-
with platisol or covered with tape, If tape is used, two
ment when it is used in high-vibration areas.
layers of rubber or vinyl plastic tape, half-lapped, is
required. Cover the handle and as much of the shaft of
Remember that interlocks are not always
the tool as practical.
provided and that they do not always work.